WorldWideScience

Sample records for network antenna starts

  1. Scheduling and Topology Design in Networks with Directional Antennas

    Science.gov (United States)

    2017-05-19

    Wireless Mesh Networks , IEEE ICC 2006. [7] E. Gelal, et. al., “Topology Management in Directional Antenna-Equipped Ad Hoc Networks , IEEE Trans. Mobile...Scheduling and Topology Design in Networks with Directional Antennas Thomas Stahlbuhk, Nathaniel M. Jones, Brooke Shrader Lincoln Laboratory...Massachusetts Institute of Technology Lexington, Massachusetts 02420–9108 Abstract—In multihop wireless networks equipped with direc- tional antennas, network

  2. On Connectivity of Wireless Sensor Networks with Directional Antennas

    Directory of Open Access Journals (Sweden)

    Qiu Wang

    2017-01-01

    Full Text Available In this paper, we investigate the network connectivity of wireless sensor networks with directional antennas. In particular, we establish a general framework to analyze the network connectivity while considering various antenna models and the channel randomness. Since existing directional antenna models have their pros and cons in the accuracy of reflecting realistic antennas and the computational complexity, we propose a new analytical directional antenna model called the iris model to balance the accuracy against the complexity. We conduct extensive simulations to evaluate the analytical framework. Our results show that our proposed analytical model on the network connectivity is accurate, and our iris antenna model can provide a better approximation to realistic directional antennas than other existing antenna models.

  3. Optimum Antenna Downtilt Angles for Macrocellular WCDMA Network

    Directory of Open Access Journals (Sweden)

    Niemelä Jarno

    2005-01-01

    Full Text Available The impact of antenna downtilt on the performance of cellular WCDMA network has been studied by using a radio network planning tool. An optimum downtilt angle has been evaluated for numerous practical macrocellular site and antenna configurations for electrical and mechanical antenna downtilt concepts. The aim of this massive simulation campaign was expected to provide an answer to two questions: firstly, how to select the downtilt angle of a macrocellular base station antenna? Secondly, what is the impact of antenna downtilt on system capacity and network coverage? Optimum downtilt angles were observed to vary between – depending on the network configuration. Moreover, the corresponding downlink capacity gains varied between – . Antenna vertical beamwidth affects clearly the required optimum downtilt angle the most. On the other hand, with wider antenna vertical beamwidth, the impact of downtilt on system performance is not such imposing. In addition, antenna height together with the size of the dominance area affect the required downtilt angle. Finally, the simulation results revealed how the importance of the antenna downtilt becomes more significant in dense networks, where the capacity requirements are typically also higher.

  4. Interference in wireless ad hoc networks with smart antennas

    KAUST Repository

    Alabdulmohsin, Ibrahim

    2014-08-01

    In this paper, we show that the use of directional antennas in wireless ad hoc networks can actually increase interference due to limitations of virtual carrier sensing. We derive a simple mathematical expression for interference in both physical and virtual carrier sense networks, which reveals counter-intuitively that receivers in large dense networks with directional antennas can experience larger interference than in omnidirectional networks unless the beamwidth is sufficiently small. Validity of mathematical analysis is confirmed using simulations.

  5. Wind-induced Dynamics Of A Deep Space Network Antenna

    Science.gov (United States)

    Gawronski, W.; Bienkiewicz, B.; Hill, R. E.

    1994-11-01

    Accurate spacecraft tracking by the NASA Deep Space Network (DSN) antennas must be assured during changing weather conditions. Wind disturbances are the main source of antenna vibrations, and consequently tracking errors. A wind force model is developed, and simulation results of wind-induced vibrations and pointing errors of the DSN antennas are presented. The antenna model includes the antenna structure, the elevation and azimuth servos, and the tracking controller. Simulation results show that pointing errors due to wind gusts are of the same order as errors due to wind steady state pressure, and that (similarly to steady state wind pressure) these errors satisfy the velocity quadratic law. The methodology presented is next used for wind disturbance estimation and for design of an antenna controller with wind disturbance rejection properties.

  6. Neural Networks for Synthesis and Optimization of Antenna Arrays

    Directory of Open Access Journals (Sweden)

    S. A. Djennas

    2007-04-01

    Full Text Available This paper describes a usual application of back-propagation neural networks for synthesis and optimization of antenna array. The neural network is able to model and to optimize the antennas arrays, by acting on radioelectric or geometric parameters and by taking into account predetermined general criteria. The neural network allows not only establishing important analytical equations for the optimization step, but also a great flexibility between the system parameters in input and output. This step of optimization becomes then possible due to the explicit relation given by the neural network. According to different formulations of the synthesis problem such as acting on the feed law (amplitude and/or phase and/or space position of the radiating sources, results on antennas arrays synthesis and optimization by neural networks are presented and discussed. However ANN is able to generate very fast the results of synthesis comparing to other approaches.

  7. On network representations of antennas inside resonating environments

    Directory of Open Access Journals (Sweden)

    F. Gronwald

    2007-06-01

    Full Text Available We discuss network representations of dipole antennas within electromagnetic cavities. It is pointed out that for a given configuration these representations are not unique. For an efficient evaluation a network representation should be chosen such that it involves as few network elements as possible. The field theoretical analogue of this circumstance is the possibility to express electromagnetic cavities' Green's functions by representations which exhibit different convergence properties. An explicit example of a dipole antenna within a rectangular cavity clarifies the corresponding interrelation between network theory and electromagnetic field theory. As an application, current spectra are calculated for the case that the antenna is nonlinearly loaded and subject to a two-tone excitation.

  8. Electromagnetics of body area networks antennas, propagation, and RF systems

    CERN Document Server

    Werner, Douglas H

    2016-01-01

    The book is a comprehensive treatment of the field, covering fundamental theoretical principles and new technological advancements, state-of-the-art device design, and reviewing examples encompassing a wide range of related sub-areas. In particular, the first area focuses on the recent development of novel wearable and implantable antenna concepts and designs including metamaterial-based wearable antennas, microwave circuit integrated wearable filtering antennas, and textile and/or fabric material enabled wearable antennas. The second set of topics covers advanced wireless propagation and the associated statistical models for on-body, in-body, and off-body modes. Other sub-areas such as efficient numerical human body modeling techniques, artificial phantom synthesis and fabrication, as well as low-power RF integrated circuits and related sensor technology are also discussed. These topics have been carefully selected for their transformational impact on the next generation of body-area network systems and beyo...

  9. Topology Design for Directional Range Extension Networks with Antenna Blockage

    Science.gov (United States)

    2016-11-01

    Topology Design for Directional Range Extension Networks with Antenna Blockage Thomas Shake MIT Lincoln Laboratory shake@ll.mit.edu Abstract...associated electronics into small aircraft to perform such range extension. In particular, the paper examines trade-offs in network topology design...aircraft, and the topology characteristics of the aerial relay network. The analysis suggests that low-degree air topologies such as rings and strings

  10. Radio propagation and adaptive antennas for wireless communication networks

    CERN Document Server

    Blaunstein, Nathan

    2014-01-01

    Explores novel wireless networks beyond 3G, and advanced 4G technologies, such as MIMO, via propagation phenomena and the fundamentals of adapted antenna usage.Explains how adaptive antennas can improve GoS and QoS for any wireless channel, with specific examples and applications in land, aircraft and satellite communications.Introduces new stochastic approach based on several multi-parametric models describing various terrestrial scenarios, which have been experimentally verified in different environmental conditionsNew chapters on fundamentals of wireless networks, cellular and non-cellular,

  11. Linking Environmental Orientation to Start-ups’ Networking Activities

    DEFF Research Database (Denmark)

    Dickel, Petra; Ritter, Thomas

    generation as their primary focus. Addressing this research gap, we develop hypotheses on the different networking activities of environmentally oriented start-ups arguing that their societal focus has a positive impact on the frequency of their networking and the size of their network. For empirically...... investigating such networking differences, we use data from 179 technology-based start-ups and show that start-ups with a strong external environmental orientation have significantly higher networking frequency and build larger networks. On the contrary, strong internal environmental orientation is linked...

  12. Research on optic antenna of space laser communication networking

    Science.gov (United States)

    Meng, Li-Xin; Li, Long; Zhang, Li-zhong; Zhao, Shan-shan; Jiang, Hui-lin

    2013-08-01

    With the highlights of the high transmission rate, large capacity, strong anti-interference and anti-capture ability, good security and small light, space laser communication becomes an important hotspot. At present, the focus of research of the laser communication system is point to point communication structure. However, from the application point of view, both the realization of space laser communication among multiple points and the establishment of the information transmission network can really have the practical value. Aiming at the problem of space laser communication network, this article puts forward the general idea about optical antenna to achieve multiple tracking goals at the same time. Through the analysis of the optical antenna, and the comparing of the current commonly used mirror driving mechanism, a new mirror driving mechanism is designed. The azimuth motion, containing circular grating feedback, is driven by torque motor,voice coil motor of fan produces pitch motion that has fan-shaped grating feedback, so that compression of the structure size to improve the efficiency of the reflector assembly. Through the establishment of the driving mechanism and the kinematic model of 3D entity, the relationship between the single drive azimuth and pitch angle following the angle of incident light is explained. The biggest ideal view area affecting the optical antenna is obtained by the simulation analysis of the kinematics model using MATLAB. The several factors of field overlap area and blind area offers a theoretical basis for structure optimization and control system for the subsequent optical antenna design.

  13. Significant performance improvement obtained in a wireless mesh network using a beamswitching antenna

    CSIR Research Space (South Africa)

    Lysko, AA

    2012-09-01

    Full Text Available The paper describes the performance enhancement obtained by adding an electronically controlled beamswitching antenna to a laboratory set up of a wireless mesh network. The antenna permits several modes offering several beam shapes and directions...

  14. Multi-platform laser communication networking optical antenna system design

    Science.gov (United States)

    Zhang, Tao

    2016-10-01

    In this paper, a new conclusion based on rotating parabolic model and a different scheme of laser communication networking antenna system has been put forward in the paper. Based on rotating parabolic antenna, a new theory of the optical properties have been deduced, which can realize larger dynamic, duplex, networking communications among multiple platforms in 360° azimuth and pitch range. Meanwhile, depending on the operation mode of the system, multiple mathematical optimization models have been established. Tracking communication range, emission energy efficiency and receiving energy efficiency have been analyzed and optimized. Relationship among opening up and low apertures, the lens unit aperture, focal length of lens unit as well as rotating parabolic focal length have been analyzed. Tracking pitching range and emission energy utilization has carried on the theoretical derivation and optimization and networking platform link between energy receiver and transmitter has been analyzed. Taking some parameters of this new system into calculation, optimized results can be utilized with MATLAB software for its application and system of communication engineering. The rotating parabolic internal can form a hollow structure, which is utilized for miniaturization, light-weighted design and realize duplex communication in a wide range and distance. Circular orbit guidance is the modern way used in dynamic tracking system. The new theory and optical antenna system has widespread applications value as well.

  15. Cold-start link prediction in multi-relational networks

    Science.gov (United States)

    Wu, Shun-yao; Zhang, Qi; Wu, Mei

    2017-10-01

    During the last decade, interaction data have accumulated exponentially in many fields and provide a new opportunity for cold start link prediction. It seems necessarily to take full advantages of diversified information. However, correlation between different interactions has to be pre-tested. Therefore, this paper abstracts complex systems as multi-relational networks, and employs latent space network model to extract low-dimensional factors of sub-networks and adopts likelihood ratio test to examine correlation between factors. Then, regression between target sub-networks and correlated auxiliary sub-networks could be established for cold start link prediction. Experiments on 8 bioinformatic data sets validate the effectiveness and potential of our strategy for network correlation analysis and cold-start link prediction.

  16. A Study on the Distributed Antenna Based Heterogeneous Cognitive Wireless Network Synchronous MAC Protocol

    Directory of Open Access Journals (Sweden)

    Lian-Fen Huang

    2015-01-01

    Full Text Available This paper introduces distributed antennas into a cognitive radio network and presents a heterogeneous network. The best contribution of this paper is that it designs a synchronous cognitive MAC protocol (DAHCWNS-MAC protocol: distributed antenna based heterogeneous cognitive wireless network synchronous MAC protocol. The novel protocol aims at combining the advantages of cognitive radio and distributed antennas to fully utilize the licensed spectrum, broaden the communication range, and improve throughput. This paper carries out the mathematical modeling and performance simulation to demonstrate its superiority in improving the network throughput at the cost of increasing antenna hardware costs.

  17. Three-Dimensional Analysis of Deep Space Network Antenna Coverage

    Science.gov (United States)

    Kegege, Obadiah; Fuentes, Michael; Meyer, Nicholas; Sil, Amy

    2012-01-01

    There is a need to understand NASA s Deep Space Network (DSN) coverage gaps and any limitations to provide redundant communication coverage for future deep space missions, especially for manned missions to Moon and Mars. The DSN antennas are required to provide continuous communication coverage for deep space flights, interplanetary missions, and deep space scientific observations. The DSN consists of ground antennas located at three sites: Goldstone in USA, Canberra in Australia, and Madrid in Spain. These locations are not separated by the exactly 120 degrees and some DSN antennas are located in the bowl-shaped mountainous terrain to shield against radiofrequency interference resulting in a coverage gap in the southern hemisphere for the current DSN architecture. To analyze the extent of this gap and other coverage limitations, simulations of the DSN architecture were performed. In addition to the physical properties of the DSN assets, the simulation incorporated communication forward link calculations and azimuth/elevation masks that constrain the effects of terrain for each DSN antenna. Analysis of the simulation data was performed to create coverage profiles with the receiver settings at a deep space altitudes ranging from 2 million to 10 million km and a spherical grid resolution of 0.25 degrees with respect to longitude and latitude. With the results of these simulations, two- and three-dimensional representations of the area without communication coverage and area with coverage were developed, showing the size and shape of the communication coverage gap projected in space. Also, the significance of this communication coverage gap is analyzed from the simulation data.

  18. An inkjet-printed UWB antenna on paper substrate utilizing a novel fractal matching network

    KAUST Repository

    Cook, Benjamin Stassen

    2012-07-01

    In this work, the smallest reported inkjet-printed UWB antenna is proposed that utilizes a fractal matching network to increase the performance of a UWB microstrip monopole. The antenna is inkjet-printed on a paper substrate to demonstrate the ability to produce small and low-cost UWB antennas with inkjet-printing technology which can enable compact, low-cost, and environmentally friendly wireless sensor network. © 2012 IEEE.

  19. A Pattern-Reconfigurable Slot Antenna for IoT Network Concentrators

    Directory of Open Access Journals (Sweden)

    Le Huy Trinh

    2017-11-01

    Full Text Available In this paper, a directional pattern-reconfigurable slot antenna at 2.4 GHz is presented. The antenna can provide three evenly-separated directional patterns and one omnidirectional pattern. The proposed solution is fully suitable for the integration in Internet of things (IoT network base stations to increase the communication range and reduce packet collisions. The performance of the proposed antenna is numerically and experimentally assessed.

  20. Tri-Band PCB Antenna for Wireless Sensor Network Transceivers in Home Automation Applications

    DEFF Research Database (Denmark)

    Rohde, John; Toftegaard, Thomas Skjødeberg

    2012-01-01

    A novel tri-band antenna design for wireless sensor network devices in home automation applications is proposed. The design is based on a combination of a conventional monopole wire antenna and discrete distributed load impedances. The load impedances are employed to ensure the degrees of freedom...

  1. PARAMETRIC ANALYSIS OF A MINIATURIZED INVERTED II SHAPED ANTENNA FOR WIRELESS SENSOR NETWORK APPLICATIONS

    Directory of Open Access Journals (Sweden)

    M. Shanmugapriya

    2015-06-01

    Full Text Available A compact and simple design of a CPW-fed planar antenna for wireless sensor network antenna application with a better size reduction is presented. The proposed antenna consists of an inverted ? shaped metal patch on a printed circuit board fed by a 50-O coplanar waveguide (CPW. The parametric analysis of length and width are made. The designed antenna’s physical dimensions are 32 mm (length x 26 mm (width x 1.6 mm (height. The antenna structure has been modeled and fabricated and its performance has been evaluated using a method of moment based electromagnetic simulator, IE3D .The return loss of -22.5 dB and VSWR of 1.34 dB are noted. The radiation pattern of the antenna proves that it radiates in all direction. The antenna is fabricated and tested and the measured results go in good agreement with simulated one.

  2. Tri Band Dual Polarized Patch Antenna System For Next Generation Cellular Networks

    Directory of Open Access Journals (Sweden)

    Syed Daniyal Ali Shah

    2017-12-01

    Full Text Available In fifth generation networks much emphasis is given to reduce the handset and base station sizes while incorporating even more features for ubiquitous connectivity. Polarization diversity is one of the methods in which a single multi-polarized antenna brings the advantages of antenna diversity. The multiband handset antennas can be made dual-polarized for improved compensation of fading effects of propagation environment especially in terrestrial bands. This paper focuses on the outcomes of the development of a horizontal and vertical polarized patch antenna scheme that operates on 3 bands 900 MHz 1.8 GHz and 2.4 GHz. The antenna system is tested for gain directivity reflection loss polarization radiation pattern and other parameters. The results are published and found are found to satisfy the requirements of cellular and data communication networks in the specified bands.

  3. Wireless Sensor Network Security Enhancement Using Directional Antennas: State of the Art and Research Challenges.

    Science.gov (United States)

    Curiac, Daniel-Ioan

    2016-04-07

    Being often deployed in remote or hostile environments, wireless sensor networks are vulnerable to various types of security attacks. A possible solution to reduce the security risks is to use directional antennas instead of omnidirectional ones or in conjunction with them. Due to their increased complexity, higher costs and larger sizes, directional antennas are not traditionally used in wireless sensor networks, but recent technology trends may support this method. This paper surveys existing state of the art approaches in the field, offering a broad perspective of the future use of directional antennas in mitigating security risks, together with new challenges and open research issues.

  4. Wireless Sensor Network Security Enhancement Using Directional Antennas: State of the Art and Research Challenges

    Directory of Open Access Journals (Sweden)

    Daniel-Ioan Curiac

    2016-04-01

    Full Text Available Being often deployed in remote or hostile environments, wireless sensor networks are vulnerable to various types of security attacks. A possible solution to reduce the security risks is to use directional antennas instead of omnidirectional ones or in conjunction with them. Due to their increased complexity, higher costs and larger sizes, directional antennas are not traditionally used in wireless sensor networks, but recent technology trends may support this method. This paper surveys existing state of the art approaches in the field, offering a broad perspective of the future use of directional antennas in mitigating security risks, together with new challenges and open research issues.

  5. SCRLH-TL Based Sequential Rotation Feed Network for Broadband Circularly Polarized Antenna Array

    Directory of Open Access Journals (Sweden)

    B. F. Zong

    2016-04-01

    Full Text Available In this paper, a broadband circularly polarized (CP microstrip antenna array using composite right/left-handed transmission line (SCRLH-TL based sequential rotation (SR feed network is presented. The characteristics of a SCRLH-TL are initially investigated. Then, a broadband and low insertion loss 45º phase shifter is designed using the SCRLH-TL and the phase shifter is employed in constructing a SR feed network for CP antenna array. To validate the design method of the SR feed network, a 2×2 antenna array comprising sequentially rotated coupled stacked CP antenna elements is designed, fabricated and measured. Both the simulated and measured results indicate that the performances of the antenna element are further enhanced when the SR network is used. The antenna array exhibits the VSWR less than 1.8 dB from 4 GHz to 7 GHz and the 3 dB axial ratio (AR from 4.4 GHz to 6.8 GHz. Also, high peak gain of 13.7 dBic is obtained. Besides, the normalized radiation patterns at the operating frequencies are symmetrical and the side lobe levels are low at φ=0º and φ=90º.

  6. Circularly Polarized Antenna Array Fed by Air-Bridge Free CPW-Slotline Network

    Directory of Open Access Journals (Sweden)

    Yilin Liu

    2017-01-01

    Full Text Available A novel design of 1×2 and 2×2 circularly polarized (CP microstrip patch antenna arrays is presented in this paper. The two CP antenna arrays are fed by sequentially rotated coplanar waveguide (CPW to slotline networks and are processed on 1 mm thick single-layer FR4 substrates. Both of the two arrays are low-profile and lightweight. An air-bridge free CPW-slotline power splitter is appropriately designed to form the feeding networks and realize the two CP antenna arrays. The mechanism of circular polarization in this design is explained. The simulated and measured impedance bandwidths as well as the 3 dB axial ratio bandwidths and the radiation patterns of the two proposed antenna arrays are presented. This proposed design can be easily extended to form a larger plane array with good performance owing to its simple structure.

  7. A Genetic Algorithm-based Antenna Selection Approach for Large-but-Finite MIMO Networks

    KAUST Repository

    Makki, Behrooz

    2016-12-29

    We study the performance of antenna selectionbased multiple-input-multiple-output (MIMO) networks with large but finite number of transmit antennas and receivers. Considering the continuous and bursty communication scenarios with different users’ data request probabilities, we develop an efficient antenna selection scheme using genetic algorithms (GA). As demonstrated, the proposed algorithm is generic in the sense that it can be used in the cases with different objective functions, precoding methods, levels of available channel state information and channel models. Our results show that the proposed GAbased algorithm reaches (almost) the same throughput as the exhaustive search-based optimal approach, with substantially less implementation complexity.

  8. Major technological innovations introduced in the large antennas of the Deep Space Network

    Science.gov (United States)

    Imbriale, W. A.

    2002-01-01

    The NASA Deep Space Network (DSN) is the largest and most sensitive scientific, telecommunications and radio navigation network in the world. Its principal responsibilities are to provide communications, tracking, and science services to most of the world's spacecraft that travel beyond low Earth orbit. The network consists of three Deep Space Communications Complexes. Each of the three complexes consists of multiple large antennas equipped with ultra sensitive receiving systems. A centralized Signal Processing Center (SPC) remotely controls the antennas, generates and transmits spacecraft commands, and receives and processes the spacecraft telemetry.

  9. Resonant RF network antennas for large-area and large-volume inductively coupled plasma sources

    Science.gov (United States)

    Hollenstein, Ch; Guittienne, Ph; Howling, A. A.

    2013-10-01

    Large-area and large-volume radio frequency (RF) plasmas are produced by different arrangements of an elementary electrical mesh consisting of two conductors interconnected by a capacitor at each end. The obtained cylindrical and planar RF networks are resonant and generate very high RF currents. The input impedance of such RF networks shows the behaviour of an RLC parallel resonance equivalent circuit. The real impedance at the resonance frequency is of great advantage for power matching compared with conventional inductive devices. Changes in the RLC equivalent circuit during the observed E-H transition will allow future interpretation of the plasma-antenna coupling. Furthermore, high power transfer efficiencies are found during inductively coupled plasma (ICP) operation. For the planar RF antenna network it is shown that the E-H transition occurs simultaneously over the entire antenna. The underlying physics of these discharges induced by the resonant RF network antenna is found to be identical to that of the conventional ICP devices described in the literature. The resonant RF network antenna is a new versatile plasma source, which can be adapted to applications in industry and research.

  10. Novel Cross-Type Network for Wide-Tuning-Range Reconfigurable Multiband Antennas

    Directory of Open Access Journals (Sweden)

    Chieh-Sen Lee

    2014-01-01

    Full Text Available This paper presents a cross-type network design with a novel reconfigurable functionality to realize a tunable multiband antenna. By attaching a reconfigurable network at the feeding port of a broadband antenna, multi-input impedance adjustment enables the production of multimatching operating bands. Each band can be independently controlled by a single component with a considerably wide tuning range and high selectivity. The experiments in this study involved using an ultra-wideband (UWB antenna connected to the proposed cross-type network. The tunable antenna operates in a dual band of fL (1.39 to 2.34 GHz and fH (2.1 to 3.6 GHz with tunable frequency ratios of 168% and 132%, respectively. The average bandwidths at fL and fH are approximately 50 MHz and 148 MHz, respectively, implying narrowband operation. The measured radiation pattern revealed that the tunable antenna exhibits a nearly omnidirectional radiation pattern at both 1.8 and 3.5 GHz. The network circuit architecture can be extended to the multiband function type by adopting this matching approach. The amount of shunt matches determines the number of operation bands.

  11. The Myth of Spatial Reuse with Directional Antennas in Indoor Wireless Networks

    Science.gov (United States)

    Lakshmanan, Sriram; Sundaresan, Karthikeyan; Rangarajan, Sampath; Sivakumar, Raghupathy

    Interference among co-channel users is a fundamental problem in wireless networks, which prevents nearby links from operating concurrently. Directional antennas allow the radiation patterns of wireless transmitters to be shaped to form directed beams. Conventionally, such beams are assumed to improve the spatial reuse (i.e. concurrency) in indoor wireless networks. In this paper, we use experiments in an indoor office setting of Wifi Access points equipped with directional antennas, to study their potential for interference mitigation and spatial reuse. In contrast to conventional wisdom, we observe that the interference mitigation benefits of directional antennas are minimal. On analyzing our experimental traces we observe that directional links do not reduce interference to nearby links due to the lack of signal confinement due to indoor multipath fading. We then use the insights derived from our study to develop an alternative approach that provides better interference reduction in indoor networks compared to directional links.

  12. Optimal Multiuser Zero Forcing with Per-Antenna Power Constraints for Network MIMO Coordination

    Directory of Open Access Journals (Sweden)

    Kaviani Saeed

    2011-01-01

    Full Text Available We consider a multicell multiple-input multiple-output (MIMO coordinated downlink transmission, also known as network MIMO, under per-antenna power constraints. We investigate a simple multiuser zero-forcing (ZF linear precoding technique known as block diagonalization (BD for network MIMO. The optimal form of BD with per-antenna power constraints is proposed. It involves a novel approach of optimizing the precoding matrices over the entire null space of other users' transmissions. An iterative gradient descent method is derived by solving the dual of the throughput maximization problem, which finds the optimal precoding matrices globally and efficiently. The comprehensive simulations illustrate several network MIMO coordination advantages when the optimal BD scheme is used. Its achievable throughput is compared with the capacity region obtained through the recently established duality concept under per-antenna power constraints.

  13. Hardware Neural Networks Modeling for Computing Different Performance Parameters of Rectangular, Circular, and Triangular Microstrip Antennas

    Directory of Open Access Journals (Sweden)

    Taimoor Khan

    2014-01-01

    Full Text Available In the last one decade, neural networks-based modeling has been used for computing different performance parameters of microstrip antennas because of learning and generalization features. Most of the created neural models are based on software simulation. As the neural networks show massive parallelism inherently, a parallel hardware needs to be created for creating faster computing machine by taking the advantages of the parallelism of the neural networks. This paper demonstrates a generalized neural networks model created on field programmable gate array- (FPGA- based reconfigurable hardware platform for computing different performance parameters of microstrip antennas. Thus, the proposed approach provides a platform for developing low-cost neural network-based FPGA simulators for microwave applications. Also, the results obtained by this approach are in very good agreement with the measured results available in the literature.

  14. The optical antenna system design research on earth integrative network laser link in the future

    Science.gov (United States)

    Liu, Xianzhu; Fu, Qiang; He, Jingyi

    2014-11-01

    Earth integrated information network can be real-time acquisition, transmission and processing the spatial information with the carrier based on space platforms, such as geostationary satellites or in low-orbit satellites, stratospheric balloons or unmanned and manned aircraft, etc. It is an essential infrastructure for China to constructed earth integrated information network. Earth integrated information network can not only support the highly dynamic and the real-time transmission of broadband down to earth observation, but the reliable transmission of the ultra remote and the large delay up to the deep space exploration, as well as provide services for the significant application of the ocean voyage, emergency rescue, navigation and positioning, air transportation, aerospace measurement or control and other fields.Thus the earth integrated information network can expand the human science, culture and productive activities to the space, ocean and even deep space, so it is the global research focus. The network of the laser communication link is an important component and the mean of communication in the earth integrated information network. Optimize the structure and design the system of the optical antenna is considered one of the difficulty key technologies for the space laser communication link network. Therefore, this paper presents an optical antenna system that it can be used in space laser communication link network.The antenna system was consisted by the plurality mirrors stitched with the rotational paraboloid as a substrate. The optical system structure of the multi-mirror stitched was simulated and emulated by the light tools software. Cassegrain form to be used in a relay optical system. The structural parameters of the relay optical system was optimized and designed by the optical design software of zemax. The results of the optimal design and simulation or emulation indicated that the antenna system had a good optical performance and a certain

  15. Using a modified Hewlett Packard 8410 network analyzer as an automated farfield antenna range receiver

    Science.gov (United States)

    Terry, John D.; Kunath, Richard R.

    1990-01-01

    A Hewlett Packard 8410 Network Analyzer was modified to be used as an automated far-field antenna range receiver. By using external mixers, analog to digital signal conversion, and an external computer/controller, the HP8410 is capable of measuring signals as low as -110 dBm. The modified receiver is an integral part of an automated far-field range which features computer controlled test antenna positioning, system measurement parameters, and data acquisition, as well as customized measurement file management. The system described was assembled and made operational, taking advantage of off-the-shelf hardware available at minimal cost.

  16. A thresholding-based antenna switching in MIMO cognitive radio networks with SWIPT-enabled secondary receiver

    KAUST Repository

    Benkhelifa, Fatma

    2017-07-31

    Simultaneous wireless power and information transfer (SWIPT) in a cognitive radio (CR) network is considered where a multiple antenna energy harvesting (EH) secondary receiver (SR) harvests the energy using the antenna switching (AS) technique. In fact, the AS technique selects a subset of the SR antennas to decode the information (namely the information decoding (ID) antennas) and the rest to harvest the energy (namely the EH antennas). In this context, we propose a thresholding-based antenna selection strategy, termed as the prioritizing data selection (PDS) scheme, which selects the ID antennas such that the received power from the secondary transmitter (ST) at these antennas is above a certain threshold. For this scheme, we derive the analytic expressions of the probability mass function (PMF) of the selected ID antennas, the average harvested energy, and the outage probability. In the simulation results, we illustrate the performance of the PDS scheme and we compare it to the prioritizing energy selection (PES) scheme which selects the EH antennas such that the received power from ST at these antennas is above a certain threshold. For both schemes, we show that there is a tradeoff between the outage probability and the average harvested energy.

  17. Circular antenna array pattern analysis using radial basis function neural network

    Science.gov (United States)

    Rama Sanjeeva Reddy, B.; Vakula, D.; Sarma, N. V. S. N.

    2013-04-01

    A method is proposed to design circular antenna array for the given gain and beam width using Artificial Neural Networks. In optimizing circular arrays, the parameters to be controlled are excitation of the elements, their separation, lengths and the circle radius. This paper deals about finding the parameters of radiation pattern of given uniform circular antenna array. Initially, the network is trained with a set of input-output data pairs. The trained network is used for testing. The training data set is generated from MATLAB simulation with number of elements N=5, 10, 15 and 20 elements of uniform circular array, respectively, distributed over a given circle, assuming 20 training cases. The number of input nodes, hidden nodes and output nodes are 20, 20 and 1, respectively. Predicted values of the neural network are compared with those of MATLAB simulation results and are found to be in agreement. This work establishes the application of Radial Basis Function Neural Network (RBFNN) for circular array pattern optimization. RBFNN is able to predict the output values with 97% of accuracy. This work proves that RBFNN can be used for circular antenna array design.

  18. Design of a Wideband Antenna for Wireless Network-On-Chip in Multimedia Applications

    Directory of Open Access Journals (Sweden)

    Fernando Gutierrez

    2017-03-01

    Full Text Available To allow fast communication—at several Gb/s—of multimedia content among processors and memories in a multi-processor system-on-chip, a new approach is emerging in literature: Wireless Network-on-Chip (WiNoC. With reference to this scenario, this paper presents the design of the key element of the WiNoC: the antenna. Specifically, a bow-tie antenna is proposed, which operates at mm-waves and can be implemented on-chip using the top metal layer of a conventional silicon CMOS (Complementary Metal Oxide Semiconductor technology. The antenna performance is discussed in the paper and is compared to the state-of-the-art, including the zig-zag antenna topology that is typically used in literature as a reference for WiNoC. The proposed bow-tie antenna design for WiNoC stands out for its good trade-off among bandwidth, gain, size and beamwidth vs. the state-of-the-art.

  19. Informal Networks and Start-Up Entrepreneurs in Spain: Networking Other Entrepreneurs and Angel Investors

    OpenAIRE

    Aliaga Isla, Rocio

    2014-01-01

    This paper contributes by containing an examination of the impact of informal networks, such as personally knowing other entrepreneurs and having access to business angel investors, have upon start-up entrepreneurs in Spain. In addition, a pseudo-panel approach is used with micro data from the Spanish Global Entrepreneurship Monitor (GEM) adult population survey over the period 2006-2009. This technique overcomes limitations found when using cross-sectional data. Moreover, this includes a sho...

  20. Design of Beam-Forming Networks for Multibeam Antenna Arrays Using Coherently Radiating Periodic Structures

    Directory of Open Access Journals (Sweden)

    A. Arce

    2012-03-01

    Full Text Available The design of a beam-forming network (BFN for a multibeam-steerable antenna array using Coherently Radiating Periodic Structures (CORPS is presented. In this design, the input ports of the feeding network are optimized using the particle swarm optimization (PSO algorithm. A two-beam design configuration of CORPS-BFN for a multibeamsteerable linear array is proposed and analyzed. The results shown in this paper present certain interesting characteristics in the array factor response, in terms of sidelobe level (SLL and directivity (D, for the scannable multibeam linear array and the feeding network simplification for the design of BFN based on CORPS.

  1. Design of Multilevel Sequential Rotation Feeding Networks Used for Circularly Polarized Microstrip Antenna Arrays

    Directory of Open Access Journals (Sweden)

    Aixin Chen

    2012-01-01

    Full Text Available Sequential rotation feeding networks can significantly improve performance of the circularly polarized microstrip antenna array. In this paper, single, double, and multiple series-parallel sequential rotation feeding networks are examined. Compared with conventional parallel feeding structures, these multilevel feeding techniques present reduction of loss, increase of bandwidth, and improvement of radiation pattern and polarization purity. By using corner-truncated square patch as the array element and adopting appropriate level of sequential rotation series-parallel feeding structures as feeding networks, microstrip arrays can generate excellent circular polarization (CP over a relatively wide frequency band. They can find wide applications in phased array radar and satellite communication systems.

  2. Smart Multifunction Antenna for Lunar/Planetary Surface Network Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA is planning a series of human and robotic missions to explore the Moon and later Mars. According to NASA SBIR topic O1.10, surface networks are needed for these...

  3. Social Network Sites: A Starting Point for Career Development Practitioners

    Science.gov (United States)

    Strehlke, Christina

    2010-01-01

    This action research study explores the career influence of social network sites (SNSs) by examining 14 web-based articles that consider the risks and opportunities of SNSs from a job search perspective. Three themes are discussed: user visibility, self-presentation, and network connections. Practical strategies are identified to help career…

  4. Simplified Antenna Group Determination of RS Overhead Reduced Massive MIMO for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Byung Moo Lee

    2017-12-01

    Full Text Available Massive multiple-input multiple-output (MIMO systems can be applied to support numerous internet of things (IoT devices using its excessive amount of transmitter (TX antennas. However, one of the big obstacles for the realization of the massive MIMO system is the overhead of reference signal (RS, because the number of RS is proportional to the number of TX antennas and/or related user equipments (UEs. It has been already reported that antenna group-based RS overhead reduction can be very effective to the efficient operation of massive MIMO, but the method of deciding the number of antennas needed in each group is at question. In this paper, we propose a simplified determination scheme of the number of antennas needed in each group for RS overhead reduced massive MIMO to support many IoT devices. Supporting many distributed IoT devices is a framework to configure wireless sensor networks. Our contribution can be divided into two parts. First, we derive simple closed-form approximations of the achievable spectral efficiency (SE by using zero-forcing (ZF and matched filtering (MF precoding for the RS overhead reduced massive MIMO systems with channel estimation error. The closed-form approximations include a channel error factor that can be adjusted according to the method of the channel estimation. Second, based on the closed-form approximation, we present an efficient algorithm determining the number of antennas needed in each group for the group-based RS overhead reduction scheme. The algorithm depends on the exact inverse functions of the derived closed-form approximations of SE. It is verified with theoretical analysis and simulation that the proposed algorithm works well, and thus can be used as an important tool for massive MIMO systems to support many distributed IoT devices.

  5. Efficient MAC Protocols for Wireless Sensor Networks Endowed with Directive Antennas: A Cross-Layer Solution

    Directory of Open Access Journals (Sweden)

    Manes Gianfranco

    2007-01-01

    Full Text Available This paper deals with a novel MAC layer protocol, namely, directive synchronous transmission asynchronous reception (D-STAR able to space-time synchronize a wireless sensor network (WSN. To this end, D-STAR integrates directional antennas within the communications framework, while taking into account both sleep/active states, according to a cross-layer design. After characterizing the D-STAR protocol in terms of functional characteristics, the related performance is presented, in terms of network lifetime gain, setup latency, and collision probability. It has shown a remarkable gain in terms of energy consumption reduction with respect to the basic approach endowed with omnidirectional antennas, without increasing the signaling overhead nor affecting the setup latency.

  6. Efficient MAC Protocols for Wireless Sensor Networks Endowed with Directive Antennas: A Cross-Layer Solution

    Directory of Open Access Journals (Sweden)

    Gianfranco Manes

    2007-07-01

    Full Text Available This paper deals with a novel MAC layer protocol, namely, directive synchronous transmission asynchronous reception (D-STAR able to space-time synchronize a wireless sensor network (WSN. To this end, D-STAR integrates directional antennas within the communications framework, while taking into account both sleep/active states, according to a cross-layer design. After characterizing the D-STAR protocol in terms of functional characteristics, the related performance is presented, in terms of network lifetime gain, setup latency, and collision probability. It has shown a remarkable gain in terms of energy consumption reduction with respect to the basic approach endowed with omnidirectional antennas, without increasing the signaling overhead nor affecting the setup latency.

  7. An LTCC Based Compact SIW Antenna Array Feed Network for a Passive Imaging Radiometer

    KAUST Repository

    Abuzaid, Hattan

    2013-02-05

    Passive millimeter-wave (PMMW) imaging is a technique that allows the detection of inherent millimeter-wave radiation emitted by bodies. Since different bodies with varying properties emit unequal power intensities, a contrast can be established to detect their presence. The advantage of this imaging scheme over other techniques, such as optical and infrared imaging, is its ability to operate under all weather conditions. This is because the relatively long wavelengths of millimeter-waves, as compared to visible light, penetrate through clouds, fog, and sandstorms. The core of a PMMW camera is an antenna, which receives the electromagnetic radiation from a scene. Because PMMW systems require high gains to operate, large antenna arrays are typically employed. This mandatory increase of antenna elements is associated with a large feeding network. Therefore, PMMW cameras usually have a big profile. In this work, two enabling technologies, namely, Substrate integrated Waveguide (SIW) and Low Temperature Co-fired Ceramic (LTCC), are coupled with an innovative design to miniaturize the passive front-end. The two technologies synergize very well with the shielded characteristics of SIW and the high density multilayer integration of LTCC. The proposed design involves a novel multilayer power divider, which is incorporated in a folded feed network structure by moving between layers. The end result is an efficient feeding network, which footprint is least affected by an increase in array size. This is because the addition of more elements is accommodated by a vertical expansion rather than a lateral one. To characterize the feed network, an antenna array has been designed and integrated through efficient transitions.The complete structure has been simulated and fabricated. The results demonstrate an excellent performance, manifesting in a gain of 20 dBi and a bandwidth of more than 11.4% at 35 GHz. These values satisfy the general requirements of a PMMW system.

  8. Radio/Antenna Mounting System for Wireless Networking under Row-Crop Agriculture Conditions

    Directory of Open Access Journals (Sweden)

    Daniel K. Fisher

    2015-07-01

    Full Text Available Interest in and deployment of wireless monitoring systems is increasing in many diverse environments, including row-crop agricultural fields. While many studies have been undertaken to evaluate various aspects of wireless monitoring and networking, such as electronic hardware components, data-collection procedures, power management, and communication protocols, little information related to physical deployment issues has been reported. To achieve acceptable wireless transmission capability, the radio/antenna must be positioned properly relative to the ground surface or crop canopy to minimize degradation of the radio signal, usually requiring the mounting of the radio/antenna above the canopy. This results in the presence of obstacles to normal agricultural equipment traffic and production operations and potential damage to the wireless monitoring system. A simple and rugged radio/antenna mounting system was designed which could be subjected to encounters with agricultural equipment without suffering physical damage. The mounting system was deployed and tested, and operated successfully following repeated encounters with various agricultural machines and implements. The radio/antenna mount is simple and inexpensive to fabricate using locally available components.

  9. Neural Networks in Antennas and Microwaves: A Practical Approach

    Directory of Open Access Journals (Sweden)

    Z. Raida

    2001-12-01

    Full Text Available Neural networks are electronic systems which can be trained toremember behavior of a modeled structure in given operational points,and which can be used to approximate behavior of the structure out ofthe training points. These approximation abilities of neural nets aredemonstrated on modeling a frequency-selective surface, a microstriptransmission line and a microstrip dipole. Attention is turned to theaccuracy and to the efficiency of neural models. The association ofneural models and genetic algorithms, which can provide a global designtool, is discussed.

  10. Network effects on Entrepreneurial Processes: Start-ups in the Dutch ICT Industry 1990-2000

    NARCIS (Netherlands)

    W. Hulsink (Wim); T. Elfring (Tom)

    2003-01-01

    textabstractThe value of networks as an integral part of the explanation of entrepreneurial success is widely acknowledged. It is unclear, however, in what way certain networks influence the success of start-up companies. The question of this paper is: 'in what way does the entrepreneur's network

  11. The DNA bank network: the start from a german initiative.

    Science.gov (United States)

    Gemeinholzer, Birgit; Dröge, Gabriele; Zetzsche, Holger; Haszprunar, Gerhard; Klenk, Hans-Peter; Güntsch, Anton; Berendsohn, Walter G; Wägele, Johann-Wolfgang

    2011-03-01

    The explicit aim of the DNA Bank Network is to close the divide between biological specimen collections and molecular sequence databases. It provides a technically optimized DNA and tissue collection service facility in the interest of all biological research, with access to well-documented DNA-containing samples and voucher specimens as well as to corresponding molecular data stored in public sequence databases. The Network enables scientists to (i) query and order DNA samples of organisms collected from natural habitats via a shared Web portal, (ii) store DNA samples for reference under optimal conditions after project completion or data publication, (iii) obtain DNA material to conduct new studies or to extend and complement previous investigations, and (iv) support good scientific practice as the deposition of DNA samples and related specimens facilitates the verification of published results.

  12. A Dual Band Frequency Reconfigurable Origami Magic Cube Antenna for Wireless Sensor Network Applications

    Directory of Open Access Journals (Sweden)

    Syed Imran Hussain Shah

    2017-11-01

    Full Text Available In this paper, a novel dual band frequency reconfigurable antenna using an origami magic cube is proposed for wireless sensor network (WSN applications. The proposed origami antenna consists of a meandered monopole folded onto three sides of the magic cube. A microstrip open-ended stub is loaded on the meandered monopole. The proposed origami magic cube can be mechanically folded and unfolded. The proposed antenna operates at 1.57 GHZ and 2.4 GHz in the folded state. In the unfolded state, the proposed antenna operates at 900 MHz and 2.3 GHz. The resonant frequency of the second band can be tunable by varying the length and position of the open stub. The origami magic cube is built on paper. Its performance is numerically and experimentally demonstrated from S-parameters and radiation patterns. The measured 10 dB impedance bandwidth of the proposed origami antenna is 18% (900–1120 MHz and 15% (2.1–2.45 GHz for the unfolded state and 20% (1.3–1.6 GHz and 14% (2.3–2.5 GHz for the folded state. The measured peak gain at 900 MHz and 2.3 GHz are 1.1 dBi and 2.32 dBi, respectively, in the unfolded state. The measured peak gain at 1.5 GHz and 2.4 GHz are 3.28 dBi and 1.98 dBi, respectively, in the folded state.

  13. OAFP starts practice-based resource/research network.

    Science.gov (United States)

    Mold, J W; Barton, E D

    1996-12-01

    The Oklahoma Academy of Family Physicians, in collaboration with the University of Oklahoma Health Sciences Center, has established a primary care practice-based research network with thirteen family practice offices currently participating. The practices are connected to each other and to the Health Sciences Center campuses in Oklahoma City and Tulsa by electronic mail and have begun their first research project involving the diagnosis and treatment of brown recluse spider bites in the primary care setting.

  14. Identification of Abnormal System Noise Temperature Patterns in Deep Space Network Antennas Using Neural Network Trained Fuzzy Logic

    Science.gov (United States)

    Lu, Thomas; Pham, Timothy; Liao, Jason

    2011-01-01

    This paper presents the development of a fuzzy logic function trained by an artificial neural network to classify the system noise temperature (SNT) of antennas in the NASA Deep Space Network (DSN). The SNT data were classified into normal, marginal, and abnormal classes. The irregular SNT pattern was further correlated with link margin and weather data. A reasonably good correlation is detected among high SNT, low link margin and the effect of bad weather; however we also saw some unexpected non-correlations which merit further study in the future.

  15. Antenna arrays in the SIGMA-eye applicator: interactions and transforming networks.

    Science.gov (United States)

    Wust, P; Fähling, H; Wlodarczyk, W; Seebass, M; Gellermann, J; Deuflhard, P; Nadobny, J

    2001-08-01

    In multiantenna applicators such as the SIGMA-60 or SIGMA-Eye, which consist of 4 or 12 pairs of antennas shunt to 4 or 12 amplifiers ("antenna couplets"), phases and amplitudes in the feed points of these antennas under certain conditions can significantly differ from the values selected at the multichannel amplifier (forward parameters), mainly due to coupling. In the SIGMA-Eye, this interaction is particularly affected by the transforming networks between the generators and the feed points, thus hampering the control of the feed point parameters. In this work, we perform measurements at existing applicators, present a formalism to describe the facts numerically, and investigate modifications of the transforming networks to improve the performance. We prepared an experimental setup for the SIGMA-Eye applicator that is fed by forward waves of a 12-channel amplifier system. In this setup, we made the water bolus, the interior of the tissue-equivalent phantom, and the entire transforming network accessible for measuring probes. Then, we constructed various alternative transforming networks such as Pawsey loops, LC matching networks, and power dividers and compared them with the original matching network of the SIGMA-Eye applicator. In particular, we utilized a high-resistive probe to determine the disturbances and influences caused by some channels with respect to some selected feed points of the SIGMA-Eye dipoles. In the original SIGMA-Eye applicator, the influences of coupling channels on the phases and voltages in the feed point of a particular antenna are largest for adjacent longitudinal channels. Here, the +/- 10 degrees phase shift and +/- 30% voltage change were observed if the reference channel (i.e., the disturbed channel) and disturbing channel are equally powered. The changes eminently increased to -30 degrees to + 100 degrees phase shift and -80% to +50% voltage change if the reference channel is fed with much lower power (four to eight-fold) than the

  16. A Design Of Feeding Network For A Dual-Linear Polarization, Stacked, Probe-Fed Microstrip Patch Antenna Array

    DEFF Research Database (Denmark)

    Jaworski, G.; Krozer, Viktor

    2004-01-01

    Components of multilayer feed network are presented for application in broad-band dual-linear polarized stacked C-band antenna. Measurement results of wide band matching circuits and different types of power divider networks constituting parts of BFN demonstrate wideband operation. Suitable...

  17. Radio Capacity Estimation for Millimeter Wave 5G Cellular Networks Using Narrow Beamwidth Antennas at the Base Stations

    Directory of Open Access Journals (Sweden)

    AlMuthanna Turki Nassar

    2015-01-01

    Full Text Available This paper presents radio frequency (RF capacity estimation for millimeter wave (mm-wave based fifth-generation (5G cellular networks using field-level simulations. It is shown that, by reducing antenna beamwidth from 65° to 30°, we can enhance the capacity of mm-wave cellular networks roughly by 3.0 times at a distance of 220 m from the base station (BS. This enhancement is far much higher than the corresponding enhancement of 1.2 times observed for 900 MHz and 2.6 GHz microwave networks at the same distance from the BS. Thus the use of narrow beamwidth transmitting antennas has more pronounced benefits in mm-wave networks. Deployment trials performed on an LTE TDD site operating on 2.6 GHz show that 6-sector site with 27° antenna beamwidth enhances the quality of service (QoS roughly by 40% and more than doubles the overall BS throughput (while enhancing the per sector throughput 1.1 times on average compared to a 3-sector site using 65° antenna beamwidth. This agrees well with our capacity simulations. Since mm-wave 5G networks will use arbitrary number of beams, with beamwidth much less than 30°, the capacity enhancement expected in 5G system when using narrow beamwidth antennas would be much more than three times observed in our simulations.

  18. Near-field antenna testing using the Hewlett Packard 8510 automated network analyzer

    Science.gov (United States)

    Kunath, Richard R.; Garrett, Michael J.

    1990-01-01

    Near-field antenna measurements were made using a Hewlett-Packard 8510 automated network analyzer. This system features measurement sensitivity better than -90 dBm, at measurement speeds of one data point per millisecond in the fast data acquisition mode. The system was configured using external, even harmonic mixers and a fiber optic distributed local oscillator signal. Additionally, the time domain capability of the HP8510, made it possible to generate far-field diagnostic results immediately after data acquisition without the use of an external computer.

  19. Cognitive Multiple-Antenna Network with Outage and Rate Margins at the Primary System

    DEFF Research Database (Denmark)

    Maham, Behrouz; Popovski, Petar

    2015-01-01

    for the primary base station (BS): space-time coding, antenna selection, and beamforming, each of them with different channel information requirements. We first consider the case in which the primary BS uses a fixed rate and we analyze the outage probability. In high-SNR scenario, we derive closed-form asymptotic...... BS and introduce a suitable rate margin and a consistent requirement for primary throughput, for which we determine the outage probability. To be able to accommodate the secondary network, a rate margin is assumed at the primary link. We calculate the exact outage probabilities and average throughput...

  20. Earth-Mars Telecommunications and Information Management System (TIMS): Antenna Visibility Determination, Network Simulation, and Management Models

    Science.gov (United States)

    Odubiyi, Jide; Kocur, David; Pino, Nino; Chu, Don

    1996-01-01

    This report presents the results of our research on Earth-Mars Telecommunications and Information Management System (TIMS) network modeling and unattended network operations. The primary focus of our research is to investigate the feasibility of the TIMS architecture, which links the Earth-based Mars Operations Control Center, Science Data Processing Facility, Mars Network Management Center, and the Deep Space Network of antennae to the relay satellites and other communication network elements based in the Mars region. The investigation was enhanced by developing Build 3 of the TIMS network modeling and simulation model. The results of several 'what-if' scenarios are reported along with reports on upgraded antenna visibility determination software and unattended network management prototype.

  1. Topology Control with Anisotropic and Sector Turning Antennas in Ad-hoc and Sensor Networks

    Directory of Open Access Journals (Sweden)

    V. Černý

    2011-01-01

    Full Text Available During the last several years, technological advances have allowed the development of small, cheap, embedded, independent and rather powerful radio devices that can self-organise into data networks. Such networks are usually called ad-hoc networks or, sometimes, depending on the application field, sensor networks. One of the first standards for ad-hoc networks to impose itself as a fully industrial framework for data gathering and control over such devices is IEEE 802.15.4 and, on top of it, its pair network architecture: ZigBee. In the case of multiple radio devices clamped into a small geographical area, the lack of radio bandwidth becomes a major problem, leading to multiple data losses and unnecessary power drain from the batteries of these small devices. This problem is usually perceived as interference. The deployment of appropriate topology control mechanisms (TC can solve interference. All of these algorithms calculate TC on the basis of isotropic antenna radiation patterns in the horizontal plane.

  2. Neighbor Discovery Algorithm in Wireless Local Area Networks Using Multi-beam Directional Antennas

    Science.gov (United States)

    Wang, Jin; Peng, Wei; Liu, Song

    2017-10-01

    Neighbor discovery is an important step for Wireless Local Area Networks (WLAN) and the use of multi-beam directional antennas can greatly improve the network performance. However, most neighbor discovery algorithms in WLAN, based on multi-beam directional antennas, can only work effectively in synchronous system but not in asynchro-nous system. And collisions at AP remain a bottleneck for neighbor discovery. In this paper, we propose two asynchrono-us neighbor discovery algorithms: asynchronous hierarchical scanning (AHS) and asynchronous directional scanning (ADS) algorithm. Both of them are based on three-way handshaking mechanism. AHS and ADS reduce collisions at AP to have a good performance in a hierarchical way and directional way respectively. In the end, the performance of the AHS and ADS are tested on OMNeT++. Moreover, it is analyzed that different application scenarios and the factors how to affect the performance of these algorithms. The simulation results show that AHS is suitable for the densely populated scenes around AP while ADS is suitable for that most of the neighborhood nodes are far from AP.

  3. S-Parameter Uncertainties in Network Analyzer Measurements with Application to Antenna Patterns

    Directory of Open Access Journals (Sweden)

    N. Yannopoulou

    2008-04-01

    Full Text Available An analytical method was developed to estimate uncertainties in full two-port Vector Network Analyzer measurements, using total differentials of S-parameters. System error uncertainties were also estimated from total differentials involving two triples of standards, in the Direct Through connection case. Standard load uncertainties and measurement inaccuracies were represented by independent differentials. Complex uncertainty in any quantity, differentiably dependent on S-parameters, is estimated by the corresponding Differential Error Region. Real uncertainties, rectangular and polar, are estimated by the orthogonal parallelogram and annular sector circumscribed about the Differential Error Region, respectively. From the user's point of view, manufactures' data may be used to set the independent differentials and apply the method. Demonstration results include: (1 System error differentials for Short, matching Load and Open pairs of opposite sex standards; (2 System error uncertainties for VNA extended by two lengthy transmission lines of opposite sex end-connectors; (3 High uncertainties in Z-parameters against frequency of an appropriately designed, DC resistive, T-Network; (4 Moderate uncertainties in amplitude and phase patterns of a designed UHF radial discone antenna (azimuthally rotated by a built positioner, under developed software control of a built hardware controller polarization coupled with a constructed gain standard antenna (stationary into an anechoic chamber.

  4. Antenna Radiation Pattern Influence on the Localization Accuracy in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    COCA, E.

    2013-05-01

    Full Text Available Localization or position determination is one of the most common applications for the wireless sensor networks. Many investigations have been made during the last decade, most of the effort being concentrated in the direction of improving the accuracy of the positioning results by using complex filtering and correction algorithms, and other techniques such as radio maps or directive antennas for the reference nodes. The most common sources of errors include reflections on nearby objects, radio frequency noise, and variable characteristics of the communication channel. In the vast majority of cases, several assumptions have been made in order to simplify the computing algorithms or the complexity of nodes, and finally their cost. The omnidirectional radiation pattern of the node antennas is such an assumption. In this paper we investigate theoretically and validate by measurements the influence of the radiation pattern on the localization accuracy of a wireless sensor node network. By taking into consideration the orientation of nodes, which could be provided by a local digital compass on each node, we demonstrate that the position accuracy could be improved with a minimum of resources. All measurements were made in radio emissions controlled environment - a semi-anechoic chamber, without affecting the generality of the proposed solution.

  5. Galileo satellite antenna modeling

    Science.gov (United States)

    Steigenberger, Peter; Dach, Rolf; Prange, Lars; Montenbruck, Oliver

    2015-04-01

    The space segment of the European satellite navigation system Galileo currently consists of six satellites. Four of them belong to the first generation of In-Orbit Validation (IOV) satellites whereas the other two are Full Operational Capability (FOC) satellites. High-precision geodetic applications require detailed knowledge about the actual phase center of the satellite and receiver antenna. The deviation of this actual phase center from a well-defined reference point is described by phase center offsets (PCOs) and phase center variations (PCVs). Unfortunately, no public information is available about the Galileo satellite antenna PCOs and PCVs, neither for the IOV, nor the FOC satellites. Therefore, conventional values for the IOV satellite antenna PCOs have been adopted for the Multi-GNSS experiment (MGEX) of the International GNSS Service (IGS). The effect of the PCVs is currently neglected and no PCOs for the FOC satellites are available yet. To overcome this deficiency in GNSS observation modeling, satellite antenna PCOs and PCVs are estimated for the Galileo IOV satellites based on global GNSS tracking data of the MGEX network and additional stations of the legacy IGS network. Two completely independent solutions are computed with the Bernese and Napeos software packages. The PCO and PCV values of the individual satellites are analyzed and the availability of two different solutions allows for an accuracy assessment. The FOC satellites are built by a different manufacturer and are also equipped with another type of antenna panel compared to the IOV satellites. Signal transmission of the first FOC satellite has started in December 2014 and activation of the second satellite is expected for early 2015. Based on the available observations PCO estimates and, optionally PCVs of the FOC satellites will be presented as well. Finally, the impact of the new antenna model on the precision and accuracy of the Galileo orbit determination is analyzed.

  6. [Nutrition in pregnancy - Practice recommendations of the Network "Healthy Start - Young Family Network"].

    Science.gov (United States)

    Koletzko, B; Bauer, C-P; Bung, P; Cremer, M; Flothkötter, M; Hellmers, C; Kersting, M; Krawinkel, M; Przyrembel, H; Rasenack, R; Schäfer, T; Vetter, K; Wahn, U; Weißenborn, A; Wöckel, A

    2012-06-01

    Nutrition, physical activity and lifestyle in pregnancy influence maternal and child health. The "Healthy start - Young Family Network" supported by the German Government with the national action plan IN FORM developed recommendations on nutrition in pregnancy. Folic acid supplements (400 µg/day) should be started before pregnancy and continue for at least the first trimester. Iodine rich foods and salt and an iodine supplement (100-150 µg/day) are recommended. Long-chain omega-3 fatty acids should be provided with ≥ 1 weekly portion of oily sea fish, or a DHA-supplement if regular fish consumption is avoided. Vitamin D supplementation is advisable unless there is regular exposure to sunlight. Iron supplements should be used based on medical history and blood testing. Vegetarian diets with nutritional supplements can provide adequate nutrition, but counselling is recommended. In contrast, a vegan diet is inadequate and requires additional micronutrient supplementation. For risk reduction of listeriosis and toxoplasmosis, raw animal foods, soft cheeses and packed fresh salads should be avoided; fresh fruit, vegetables and salad should be washed well and consumed promptly. Pregnant women should remain physically active and perform sports with moderate intensity. They should avoid alcohol, active and passive smoking. Up to 3 daily cups of coffee are considered harmless, but energy drinks should be avoided. Childhood allergy is not reduced by avoiding certain foods in pregnancy whereas oily sea fish is recommended. Health care professions should lead parents to health-promoting lifestyles. Subjects of part 1 of the article are practice recommendations on nutrition, on energy needs, micronutrient needs and body weight/weight gain in pregnancy. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Pole discontinuity removal using artificial neural networks for microstrip antenna design

    Science.gov (United States)

    Kulshrestha, Sanjeev; Chheda, Deven J.; Chakrabarty, S. B.; Jyoti, Rajeev; Sharma, S. B.

    2011-12-01

    This article presents the use of artificial neural networks for the evaluation of integrals with finite number of pole singularities while formulating the integral equation for the electric surface current density. A feed-forward single-layer back-propagated artificial neural network (ANN) model has been trained to approximate the discontinuous integrand function. Generation of a soft continuous function obtained from the ANN model and closed-loop expressions for the evaluation of the integrals are presented. The proposed technique is applied to compute the input impedance of microstrip antenna and results have been compared with IE3D. Integration has been performed using n-point Gaussian quadrature rule for evaluating the reaction matrix.

  8. Experimental Evaluation of Optically Polished Aluminum Panels on the Deep Space Network's 34 Meter Antenna

    Science.gov (United States)

    Vilnrotter, V.

    2011-01-01

    The potential development of large aperture ground?based "photon bucket" optical receivers for deep space communications has received considerable attention recently. One approach currently under investigation is to polish the aluminum reflector panels of 34?meter microwave antennas to high reflectance, and accept the relatively large spotsize generated by state of?the?art polished aluminum panels. Theoretical analyses of receiving antenna pointing, temporal synchronization and data detection have been addressed in previous papers. Here we describe the experimental effort currently underway at the Deep Space Network (DSN) Goldstone Communications Complex in California, to test and verify these concepts in a realistic operational environment. Two polished aluminum panels (a standard DSN panel polished to high reflectance, and a custom designed aluminum panel with much better surface quality) have been mounted on the 34 meter research antenna at Deep?Space Station 13 (DSS?13), and a remotely controlled CCD camera with a large CCD sensor in a weather?proof container has been installed next to the subreflector, pointed directly at the custom polished panel. The point?spread function (PSF) generated by the Vertex polished panel has been determined to be smaller than the sensor of the CCD camera, hence a detailed picture of the PSF can be obtained every few seconds, and the sensor array data processed to determine the center of the intensity distribution. In addition to estimating the center coordinates, expected communications performance can also been evaluated with the recorded data. The results of preliminary pointing experiments with the Vertex polished panel receiver using the planet Jupiter to simulate the PSF generated by a deep?space optical transmitter are presented and discussed in this paper.

  9. Prioritizing Data/Energy Thresholding-Based Antenna Switching for SWIPT-Enabled Secondary Receiver in Cognitive Radio Networks

    KAUST Repository

    Benkhelifa, Fatma

    2017-12-04

    Simultaneous wireless power and information transfer (SWIPT) is considered in cognitive radio networks with a multi-antenna energy harvesting (EH) secondary receiver (SR). The SR harvests the energy from the secondary transmitter and primary transmitter. The SR uses the antenna switching technique which selects a subset of antennas to decode the information (namely the information decoding (ID) antennas) and the rest to harvest the energy (namely the EH antennas). The AS technique is performed via a thresholding-based strategy inspired from the maximum ratio combining technique with an output threshold (OT-MRC) which is proposed in two ways: the prioritizing data selection (PDS) scheme, and the prioritizing energy selection (PES) scheme. For both schemes, we study the expressions and the asymptotic results of the probability mass function of the selected ID antennas, the average harvested energy, the power outage probability, and the data outage probability. We deduce the performance of the joint PDS and PES scheme. We evaluate all performance metrics for the Rayleigh and Nakagami fading channels. Through the simulation results, we show the impact of different simulation parameters on the performance metrics. We also show that there is a tradeoff between the data and energy performance metrics.

  10. A Thresholding-Based Antenna Switching in SWIPT-Enabled MIMO Cognitive Radio Networks with Co-Channel Interference

    KAUST Repository

    Benkhelifa, Fatma

    2016-10-23

    In this paper, we consider the simultaneous wireless power and information transfer (SWIPT) for spectrum sharing (SS) in cognitive radio (CR) networks with a multiple antenna SWIPT-Enabled secondary receiver (SR). The SR harvests the energy from the signals sent from the secondary transmitter (ST) and the interfering signals sent from the primary transmitter (PT). Moreover, the ST uses the antenna switching (AS) technique which selects a subset of the antennas to decode the information and the rest to harvest the energy. The antenna selection is performed via a thresholding strategy inspired from the maximum ratio combining (MRC) technique with an output threshold (OT-MRC). The thresholding-based antenna selection strategy is proposed in two ways: one is prioritizing the information data and the other is prioritizing the harvested energy. For the two proposed selection schemes, we study the probability mass function of the selected antennas, the average harvested energy, and the data transmission outage probability. Through the analytic expressions and the simulation results, we show that there is a tradeoff between the outage probability and the harvested energy for both schemes. We see also that the preference of one scheme on the other is also affected by this energy-data trade off.

  11. On Secure Underlay MIMO Cognitive Radio Networks with Energy Harvesting and Transmit Antenna Selection

    KAUST Repository

    Lei, Hongjiang

    2017-03-20

    In this paper, we consider an underlay multipleinput- multiple-output (MIMO) cognitive radio network (CRN) including a pair of primary nodes, a couple of secondary nodes, and an eavesdropper, where the secondary transmitter is powered by the renewable energy harvested from the primary transmitter in order to improve both energy efficiency and spectral efficiency. Based on whether the channel state information (CSI) of wiretap links are available or not, the secrecy outage performance of the optimal antenna selection (OAS) scheme and suboptimal antenna selection (SAS) scheme for underlay MIMO CRN with energy harvesting are investigated and compared with traditional space-time transmission scheme. The closed-form expressions for exact and asymptotic secrecy outage probability are derived. Monte-Carlo simulations are conducted to testify the accuracy of the analytical results. The analysis illustrates that OAS scheme outperforms SAS scheme. Furthermore, the asymptotic result shows that no matter which scheme is considered, the OAS and SAS schemes can achieve the same secrecy diversity order.

  12. Total Differential Errors in One-Port Network Analyzer Measurements with Application to Antenna Impedance

    Directory of Open Access Journals (Sweden)

    P. Zimourtopoulos

    2007-06-01

    Full Text Available The objective was to study uncertainty in antenna input impedance resulting from full one-port Vector Network Analyzer (VNA measurements. The VNA process equation in the reflection coefficient ρ of a load, its measurement m and three errors Es, determinable from three standard loads and their measurements, was considered. Differentials were selected to represent measurement inaccuracies and load uncertainties (Differential Errors. The differential operator was applied on the process equation and the total differential error dρ for any unknown load (Device Under Test DUT was expressed in terms of dEs and dm, without any simplification. Consequently, the differential error of input impedance Z -or any other physical quantity differentiably dependent on ρ- is expressible. Furthermore, to express precisely a comparison relation between complex differential errors, the geometric Differential Error Region and its Differential Error Intervals were defined. Practical results are presented for an indoor UHF ground-plane antenna in contrast with a common 50 Ω DC resistor inside an aluminum box. These two built, unshielded and shielded, DUTs were tested against frequency under different system configurations and measurement considerations. Intermediate results for Es and dEs characterize the measurement system itself. A number of calculations and illustrations demonstrate the application of the method.

  13. Multiwavelength optical beam forming network with ring resonator-based binary-tree architecture for broadband phased array antenna systems

    NARCIS (Netherlands)

    Burla, M.; Khan, M.R.H.; Zhuang, L.; Roeloffzen, C.G.H.

    2008-01-01

    Integrated optical beam forming networks (OBFNs) offer many advantages for phased array applications. ORR-based true-time-delay units can be cascaded in a binary tree topology and tuned for continuously-adjustable broadband time delay. Nonetheless, with large number of antenna elements, the OBFN may

  14. Software-based microwave CT system consisting of antennas and vector network analyzer.

    Science.gov (United States)

    Ogawa, Takahiro; Miyakawa, Michio

    2011-01-01

    We have developed a software-based microwave CT (SMCT) that consists of antennas and a vector network analyzer. Regardless of the scanner type, SMCT collects the S-parameters at each measurement position in the frequency range of interest. After collecting all the S-parameters, it calculates the shortest path to obtain the projection data for CPMCT. Because of the redundant data in SMCT, the calculation of the projection is easily optimized. Therefore, the system can improve the accuracy and stability of the measurement. Furthermore, the experimental system is constructed at a reasonable cost. Hence, SMCT is useful for imaging experiments for CP-MCT and particularly for basic studies. This paper describes the software-based microwave imaging system, and experimental results show the usefulness of the system.

  15. Cooperative beamforming for dual-hop amplify-and-forward multi-antenna relaying cellular networks

    KAUST Repository

    Xing, Chengwen

    2012-11-01

    In this paper, linear beamforming design for amplify-and-forward relaying cellular networks is considered, in which base station, relay station and mobile terminals are all equipped with multiple antennas. The design is based on minimum mean-square-error criterion, and both uplink and downlink scenarios are considered. It is found that the downlink and uplink beamforming design problems are in the same form, and iterative algorithms with the same structure can be used to solve the design problems. For the specific cases of fully loaded or overloaded uplink systems, a novel algorithm is derived and its relationships with several existing beamforming design algorithms for conventional MIMO or multiuser systems are revealed. Simulation results are presented to demonstrate the performance advantage of the proposed design algorithms. © 2012 Published by Elsevier B.V. All rights reserved.

  16. Collaborative Localization in Wireless Sensor Networks via Pattern Recognition in Radio Irregularity Using Omnidirectional Antennas

    Directory of Open Access Journals (Sweden)

    Tzu-Yun Lai

    2010-01-01

    Full Text Available In recent years, various received signal strength (RSS-based localization estimation approaches for wireless sensor networks (WSNs have been proposed. RSS-based localization is regarded as a low-cost solution for many location-aware applications in WSNs. In previous studies, the radiation patterns of all sensor nodes are assumed to be spherical, which is an oversimplification of the radio propagation model in practical applications. In this study, we present an RSS-based cooperative localization method that estimates unknown coordinates of sensor nodes in a network. Arrangement of two external low-cost omnidirectional dipole antennas is developed by using the distance-power gradient model. A modified robust regression is also proposed to determine the relative azimuth and distance between a sensor node and a fixed reference node. In addition, a cooperative localization scheme that incorporates estimations from multiple fixed reference nodes is presented to improve the accuracy of the localization. The proposed method is tested via computer-based analysis and field test. Experimental results demonstrate that the proposed low-cost method is a useful solution for localizing sensor nodes in unknown or changing environments.

  17. Study of the Start-Up Ecosystem in Lima, Peru: Analysis of Interorganizational Networks

    Directory of Open Access Journals (Sweden)

    Carlos Hernandez

    2017-04-01

    Full Text Available According to the literature, In the context of changes at a global level the formation of new businesses drives the economy, being important start-ups, which are linked to a community of entrepreneurs, mentors, incubators, accelerators, providers of common services, angel investors, venture capitalists, universities and public support entities, which together configure an ecosystem that is linked to other ecosystems. In this way, this work focuses on the Lima, Peru ecosystem with the aim of providing an understanding of the interorganizational networks that are established based on the analysis of the interactions that occur in the LinkedIn social network. Definitions, methodology, results and conclusions are presented.

  18. Substrate integrated antennas and arrays

    CERN Document Server

    Cheng, Yu Jian

    2015-01-01

    Substrate Integrated Antennas and Arrays provides a single source for cutting-edge information on substrate integrated circuits (SICs), substrate integrated waveguide (SIW) feeding networks, SIW slot array antennas, SIC traveling-wave antennas, SIW feeding antennas, SIW monopulse antennas, and SIW multibeam antennas. Inspired by the author's extensive research, this comprehensive book:Describes a revolutionary SIC-based antenna technique with the potential to replace existing antenna technologiesExamines theoretical and experimental results connected to electrical and mechanical performanceExp

  19. A Dual-Band Antenna for RF Energy Harvesting Systems in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    A. Bakkali

    2016-01-01

    Full Text Available In this paper, we focus on ambient radio frequency energy available from commercial broadcasting stations in order to provide a system based on RF energy harvesting using a new design of receiving antenna. Several antenna designs have been proposed for use in RF energy harvesting systems, as a pertinent receiving antenna design is highly required since the antenna features can affect the amount of energy harvested. The proposed antenna is aimed at greatly increasing the energy harvesting efficiency over Wi-Fi bands: 2.45 GHz and 5 GHz. This provides a promising alternative energy source in order to power sensors located in harsh environments or remote places, where other energy sources are impracticable. The dual-band antenna can be easily integrated with RF energy harvesting system on the same circuit board. Simulations and measurements were carried out to evaluate the antenna performances and investigate the effects of different design parameters on the antenna performance. The receiving antenna meets the required bandwidth specification and provides peak gain of more than 4 dBi across the operating band.

  20. Optically controlled reconfigurable antenna for 5G future broadband cellular communication networks

    DEFF Research Database (Denmark)

    Costa, I.F. da; Spadoti, D. H.; Cerqueira Sodre Jr., Arismar

    2017-01-01

    This paper presents an optically controlled reconfigurable antenna for millimetre-wave frequency range. Silicon switches are used to control the optical reconfiguration, modifying the frequency response and radiation pattern of the antenna design. Therefore, the system can switch between the ligh...

  1. Using adaline neural network for performance improvement of smart antennas in TDD wireless communications.

    Science.gov (United States)

    Kavak, Adnan; Yigit, Halil; Ertunc, H Metin

    2005-11-01

    In time-division-duplex (TDD) mode wireless communications, downlink beamforming performance of a smart antenna system at the base station can be degraded due to variation of spatial signature vectors corresponding to mobile users especially in fast fading scenarios. To mitigate this, downlink beams must be controlled by properly adjusting their weight vectors in response to changing propagation dynamics. This can be achieved by modeling the spatial signature vectors in the uplink period and then predicting them to be used as beamforming weight vectors for the new mobile position in the downlink transmission period. We show that ADAptive LInear NEuron (ADALINE) network modeling based prediction of spatial signatures provides certain level of performance improvement compared to conventional beamforming method that employs spatial signature obtained in previous uplink interval. We compare the performance of ADALINE with autoregressive (AR) modeling based predictions under varying channel propagation (mobile speed, multipath angle spread, and number of multipaths), and filter order/delay conditions. ADALINE modeling outperforms AR modeling in terms of downlink SNR improvement and relative error improvement especially under high mobile speeds, i.e., V = 100 km/h.

  2. An Effective Recommender Algorithm for Cold-Start Problem in Academic Social Networks

    Directory of Open Access Journals (Sweden)

    Vala Ali Rohani

    2014-01-01

    Full Text Available Abundance of information in recent years has become a serious challenge for web users. Recommender systems (RSs have been often utilized to alleviate this issue. RSs prune large information spaces to recommend the most relevant items to users by considering their preferences. Nonetheless, in situations where users or items have few opinions, the recommendations cannot be made properly. This notable shortcoming in practical RSs is called cold-start problem. In the present study, we propose a novel approach to address this problem by incorporating social networking features. Coined as enhanced content-based algorithm using social networking (ECSN, the proposed algorithm considers the submitted ratings of faculty mates and friends besides user’s own preferences. The effectiveness of ECSN algorithm was evaluated by implementing it in MyExpert, a newly designed academic social network (ASN for academics in Malaysia. Real feedbacks from live interactions of MyExpert users with the recommended items are recorded for 12 consecutive weeks in which four different algorithms, namely, random, collaborative, content-based, and ECSN were applied every three weeks. The empirical results show significant performance of ECSN in mitigating the cold-start problem besides improving the prediction accuracy of recommendations when compared with other studied recommender algorithms.

  3. The use of antenna radiation pattern in node localisation algorithms for wireless sensor networks

    CSIR Research Space (South Africa)

    Mwila, MK

    2014-08-01

    Full Text Available due to the limited accuracy inherent to the current ranging model. These models, however, make the assumption that the antenna radiation pattern is omnidirectional targeted to simplifying the complexity of the algorithms. An increasing number of sensor...

  4. Some considerations regarding the choice of a matching network for electrically small loop antennas

    CSIR Research Space (South Africa)

    Bowles, BA

    1978-11-01

    Full Text Available with the antennas is analysed by means of a desk-top calculator. Graphical plots of the important parameters indicate the simple series tuned circuit to have important advantages. Furthermore, narrowband radio frequency modulation techniques are shown...

  5. Fully non-inductive plasma start-up with lower-hybrid waves using the outboard-launch and top-launch antennas on the TST-2 spherical tokamak

    Directory of Open Access Journals (Sweden)

    Tsujii Naoto

    2017-01-01

    Full Text Available Removal of the central solenoid is essential to realize an economical spherical tokamak fusion reactor, but non-inductive plasma start-up is a challenge. On the TST-2 spherical tokamak, non-inductive plasma start-up using lower-hybrid (LH waves has been investigated. Using the capacitively-coupled combline (CCC antenna installed at the outboard midplane, fully non-inductive plasma current ramp-up up to a quarter of that of the typical Ohmic discharges has been achieved. Although it was desirable to keep the density low during the plasma current ramp-up to avoid the LH density limit, it was recognized that there was a maximum current density that could be carried by a given electron density. Since the density needed to increase as the plasma current was ramped-up, the achievable plasma current was limited by the maximum operational toroidal field of TST-2. The top-launch CCC antenna was installed to access higher density with up-shift of the parallel index of refraction. Numerical analysis of LH current drive with the outboard-launch and top-launch antennas was performed and the results were qualitatively consistent with the experimental observations.

  6. Compact, Slotted, Printed Antennas for Dual-Band Communication in Future Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Constantine G. Kakoyiannis

    2013-01-01

    Full Text Available Inverted-F antennas (IFAs are a primary choice to implement the radiating system of portable devices. A tried and tested idea can remain topical if proven useful in modern applications. This paper shows that printed IFAs (PIFAs are capable of forming robust, compact, dual-band radiating systems for wireless microsensors with an adjustable spacing between bands. Reactive tuning was applied by inductively loading the structures with prefractal slots; inductive slot loading degenerates higher-order resonances and increases the fractional bandwidth (FBW. The current distributions revealed that most of the element area is used for radiation at both resonances. In radiation terms, the antennas provide satisfactory gains and high efficiencies (≥82%. A simple figure of merit is used to compare the performance of the three PIFAs head to head. Operation at 2.5 GHz and 5.5 GHz indicated that changes in slot geometry almost double the FBW. The proposed antennas serve both the 5.15–5.35 GHz U-NII and the 5.8 GHz ISM bands; at the lower band, their size is less or equal to the half-wavelength dipole. This study of dual-band antennas also showed that the aggregate FBW of a PIFA is bounded; by degenerating higher-order modes, the designer redistributes whatever bandwidth is available by the antenna itself to the desired bands.

  7. Radio interferometric determination of intercontinental baselines and earth orientation utilizing deep space network antennas - 1971 to 1980

    Science.gov (United States)

    Sovers, O. J.; Thomas, J. B.; Fanselow, J. L.; Cohen, E. J.; Purcell, G. H., Jr.; Rogstad, D. H.; Skjerve, L. J.; Spitzmesser, D. J.

    1984-01-01

    Progress has been made toward the realization of the potential of radio interferometry for measuring crustal motions and global rotations of the earth with accuracies at the centimeter level. In this connection, a series of experiments, primarily with NASA's Deep Space Network (DSN) antennas, has been conducted to develop two generations of very long baseline interferometric (VLBI) systems. A description is presented of the employed techniques, an analysis of the experiments, and the results of geophysical significance. Attention is given to the interferometry technique, the geometric delay model, propagation media calibrations, and the observing strategy.

  8. Terminal Antennas in ACE2

    Directory of Open Access Journals (Sweden)

    M. Martinez-Vazquez

    2008-06-01

    Full Text Available The ACE Network of Excellence was a European Commission funded Network of Excellence, which lasted from 2004 to 2007. One of the activities performed by this Network was in the frame of terminal antennas. In this activity, three aspects were covered in three projects: Small antenna technologies, small terminal antenna technologies and benchmarking of small terminal antennas measurement facilities. The overall aim was to identify the newest trends in antenna design and measurement for personal communications devices, and suggest novel solutions and design methodologies for various applications. The results of this work are presented in this paper.

  9. GOFC-GOLD/LCLUC/START Regional Networking: building capacity for science and decision-making.

    Science.gov (United States)

    Justice, C. O.; Vadrevu, K.; Gutman, G.

    2016-12-01

    Over the past 20 years, the international GOFC-GOLD Program and START, with core funding from the NASA LCLUC program and ESA have been developing regional networks of scientists and data users for scientific capacity building and sharing experience in the use and application of Earth Observation data. Regional networks connect scientists from countries with similar environmental and social issues and often with shared water and airsheds. Through periodic regional workshops, regional and national projects are showcased and national priorities and policy drivers are articulated. The workshops encourage both north-south and south-south exchange and collaboration. The workshops are multi-sponsored and each include a training component, targeting early career scientists and data users from the region. The workshops provide an opportunity for regional scientists to publish in peer-reviewed special editions focused on regional issues. Currently, the NASA LCLUC program funded "South and Southeast Asia Regional Initiative (SARI)" team is working closely with the USAID/NASA SERVIR program to implement some capacity building and training activities jointly in south/southeast Asian countries to achieve maximum benefit.

  10. Feed-forward control upgrade of the deep space network antennas

    Science.gov (United States)

    Gawronski, W.

    1992-01-01

    In order to improve the accuracy of high-rate tracking of NASA's DSN antennas, the position-loop controller has been upgraded with a feed-forward loop. Conditions for perfect and approximate tracking with the feed-forward loop are presented. The feed-forward loop improves tracking performance and preserves wind disturbance rejection properties of the previous closed-loop system.

  11. Double dipole antenna for dual-band wireless local area networks applications

    CSIR Research Space (South Africa)

    Steyn, JM

    2009-09-01

    Full Text Available band dipole is rhombus shaped and radiates above a planar ground plane, while radiation from the rectangular higher band dipole is directed through the use of a passive director. The antenna is characterized in terms of impedance bandwidth, gain...

  12. Implementation of an Optical-Wireless Network with Spectrum Sensing and Dynamic Resource Allocation Using Optically Controlled Reconfigurable Antennas

    Directory of Open Access Journals (Sweden)

    E. Raimundo-Neto

    2014-01-01

    Full Text Available This work proposes the concept and reports the implementation of an adaptive and cognitive radio over fiber architecture. It is aimed at dealing with the new demands for convergent networks by means of simultaneously providing the functionalities of multiband radiofrequency spectrum sensing, dynamic resource allocation, and centralized processing capability, as well as the use of optically controlled reconfigurable antennas and radio over fiber technology. The performance of this novel and innovative architecture has been evaluated in a geographically distributed optical-wireless network under real conditions and for different fiber lengths. Experimental results demonstrate reach extension of more than 40 times and an enhancement of more than 30 dB in the carrier to interference plus noise ratio parameter.

  13. Multiband Antennas for SDR Applications

    Directory of Open Access Journals (Sweden)

    E. Surducan

    2009-01-01

    Full Text Available We present multiband antennas configurations for SDR applications. Using a composite folded dipole structure as starting point, we derived more complex antenna configurations to support multiple communication protocols for mobile application with linear and circular polarizations. Prototypes as single antenna with circular polarization, tunable single antenna with PIN diode and MIMO systems with three and four antennas, all derivatives of the same basic structure, were produced in an iterative fashion until the desired parameters were achieved. These antennas are suitable for microstrip circuit realizations and can be included in the printed circuit board (PCB of the device, or used as stand alone. The shapes and measurement results are presented throughout the paper. From the illustrated graphs it can be seen that the stand-alone antennas exhibit positive gain for all the frequency bands of interest while the separation between antennas, for the multiple-input multiple-output (MIMO case, is better than 15 dB.

  14. Experimental Evaluation of the "Polished Panel Optical Receiver" Concept on the Deep Space Network's 34 Meter Antenna

    Science.gov (United States)

    Vilnrotter, Victor A.

    2012-01-01

    The potential development of large aperture ground-based "photon bucket" optical receivers for deep space communications has received considerable attention recently. One approach currently under investigation proposes to polish the aluminum reflector panels of 34-meter microwave antennas to high reflectance, and accept the relatively large spotsize generated by even state-of-the-art polished aluminum panels. Here we describe the experimental effort currently underway at the Deep Space Network (DSN) Goldstone Communications Complex in California, to test and verify these concepts in a realistic operational environment. A custom designed aluminum panel has been mounted on the 34 meter research antenna at Deep-Space Station 13 (DSS-13), and a remotely controlled CCD camera with a large CCD sensor in a weather-proof container has been installed next to the subreflector, pointed directly at the custom polished panel. Using the planet Jupiter as the optical point-source, the point-spread function (PSF) generated by the polished panel has been characterized, the array data processed to determine the center of the intensity distribution, and expected communications performance of the proposed polished panel optical receiver has been evaluated.

  15. Passive Component Network for Antenna Isolation in MIMO Systems for Handheld Terminals

    DEFF Research Database (Denmark)

    Tatomirescu, Alexandru; Pelosi, Mauro; Knudsen, Mikael B.

    2011-01-01

    This paper presents an improved method to isolate the ports for a MIMO antenna in hand-held devices using lumped components. It has been analyzed through simulation and measurement. The total efficiency and the envelope correlation have been evaluated. Compared to the case with no decoupling...... mechanism, the efficiency from the scattering parameters increases significantly and the envelope correlation coefficient decreases dramatically. Nevertheless, when choosing the components, the ohmic losses must receive extra consideration in order to maximize the system’s total efficiency. Furthermore...

  16. How network-based incubation helps start-up performance : a systematic review against the background of management theories

    NARCIS (Netherlands)

    Eveleens, Chris P.; van Rijnsoever, Frank J.; Niesten, Eva M M I

    2017-01-01

    The literature on how network-based incubation influences the performance of technology-based start-ups has recently grown considerably and provided valuable insights. However, at the same time this literature has become quite fragmented, inconsistently conceptualised, and theoretically

  17. Smart antennas

    CERN Document Server

    Godara, Lal Chand

    2004-01-01

    INTRODUCTION Antenna GainPhased Array AntennaPower Pattern Beam Steering Degree of Freedom Optimal AntennaAdaptive AntennaSmart AntennaSummary NARROWBAND PROCESSINGSignal Model Conventional BeamformerNull Steering BeamformerOptimal BeamformerOptimization Using Reference SignalBeam Space Processing Effect of ErrorsNotation and AbbreviationsReferencesADAPTIVE PROCESSINGSample Matrix Inversion AlgorithmUnconstrained Least Mean Squares AlgorithmNormalized Least Mean Squares AlgorithmConstrained

  18. An Eight Element S-Band Antenna Array for Evaluating Directional Mesh Networking Using Software Definded Radios

    Science.gov (United States)

    2014-12-01

    MHZ / NORMALIZED. ............................................................ 10 FIGURE 15: ANTENNA TESTING IN AFRL’S ANECHOIC CHAMBER ...required for taking pattern measurements in the anechoic chamber , given that the antenna would be mounted at the top of a model tower and therefor...were made to characterize antenna array and beamformer performance. Testing was conducted in AFRL Rome Research Site’s anechoic chamber . Data was

  19. A new jamming technique for secrecy in multi-antenna wireless networks

    KAUST Repository

    Bakr, Omar

    2010-06-01

    We consider the problem of secure wireless communication in the presence of an eavesdropper when the transmitter has multiple antennas, using a variation of the recently proposed artificial noise technique. Under this technique, the transmitter sends a pseudo-noise jamming signal to selectively degrade the link to the eavesdropper without affecting the desired receiver. The previous work in the literature focuses on ideal Gaussian signaling for both the desired signal and the noise signal. The main contribution of this paper is to show that the Gaussian signaling model has important limitations and propose an alternative "induced fading" jamming technique that takes some of these limitations into account. Specifically we show that under the Gaussian noise scheme, the eavesdropper is able to recover the desired signal with very low bit error rates when the transmitter is constrained to use constant envelope signaling. Furthermore, we show that an eavesdropper with multiple antennas is able to use simple, blind constant-envelope algorithms to completely remove the Gaussian artificial noise signal and thus defeat the secrecy scheme. We propose an alternative scheme that induces artificial fading in the channel to the eavesdropper, and show that it outperforms the Gaussian noise scheme in the sense of causing higher bit error rates at the eavesdropper and is also more resistant to constant modulus-type algorithms. © 2010 IEEE.

  20. Characterization and Calibration of the 12-m Antenna in Warkworth, New Zealand

    Science.gov (United States)

    Gulyaev, Sergei; Natusch, Tim; Wilson, David

    2010-01-01

    The New Zealand 12-m antenna is scheduled to start participating in regular IVS VLBI sessions from the middle of 2010. Characterization procedures and results of calibration of the New Zealand 12- m radio telescope are presented, including the main reflector surface accuracy measurement, pointing model creation, and the system equivalent flux density (SEFD) determination in both S and X bands. Important issues of network connectivity, co-located geodetic systems, and the use of the antenna in education are also discussed.

  1. Entrepreneur online social networks: structure, diversity and impact on start-up survival

    NARCIS (Netherlands)

    Song, Y.; Vinig, T.

    2012-01-01

    In this paper, we discuss the results of a pilot study in which we use a novel approach to collect entrepreneur online social network data from LinkedIn, Facebook and Twitter. We studied the size and structure of entrepreneur social networks by analysing the online network industry and location

  2. Network brokers or hit makers? Analyzing the influence of incubation on start-up investments

    NARCIS (Netherlands)

    Van Rijnsoever, Frank J.|info:eu-repo/dai/nl/314100334; Van Weele, Marijn A.; Eveleens, Chris P.|info:eu-repo/dai/nl/369284704

    Incubators are a prominent way to support technology based start-ups. Yet, it remains unclear to what extent these incubators enhance start-up performance, nor is it known through which mechanisms this would occur. In this paper we test two mechanisms to explain the relationship between incubation

  3. Layout Of Antennas And Cables In A Large Array

    Science.gov (United States)

    Logan, Ronald T., Jr.

    1995-01-01

    Layout devised to minimize total land area occupied by large phased array of antennas and to minimize total length of cables in array. In original intended application, array expanded version of array of paraboloidal-dish microwave communication antennas of Deep Space Network. Layout also advantageous for other phased arrays of antennas and antenna elements, including notably printed-circuit microwave antenna arrays.

  4. Deployable antenna

    Science.gov (United States)

    Fink, Patrick W. (Inventor); Dobbins, Justin A. (Inventor); Lin, Greg Y. (Inventor); Chu, Andrew W. (Inventor); Scully, Robert C. (Inventor)

    2006-01-01

    A deployable antenna and method for using wherein the deployable antenna comprises a collapsible membrane having at least one radiating element for transmitting electromagnetic waves, receiving electromagnetic waves, or both.

  5. How network-based incubation helps start-up performance: a systematic review against the background of management theories

    OpenAIRE

    Eveleens, Chris P.; Frank J. van Rijnsoever; Niesten, Eva M M I

    2017-01-01

    The literature on how network-based incubation influences the performance of technology-based start-ups has recently grown considerably and provided valuable insights. However, at the same time this literature has become quite fragmented, inconsistently conceptualised, and theoretically underdeveloped. Therefore, this article uses three management theories to structure the literature, improve the theoretical underpinning and develop an agenda for further research. The management theories are ...

  6. Next Generation Radio over Fiber Network Management for a Distributed Antenna System

    DEFF Research Database (Denmark)

    Santiago, Carlos; Gangopadhyay, Bodhisattwa; arsenio, Artur

    2009-01-01

    Dette dokument beskriver funktioner og procedurer i futon Radio Over Fiber Manager til at operere med det øvre (net) og nederste (fysiske) lag, der anvendes til transport af trådløse signaler mellem en central enhed (CU) og Remote Antenna Units. Også, det giver nogle mekanismer og procedurer, der...... skal anvendes i tilfælde af fejl, samtidig med at end-to-end service problemløsning og service kvalitetsstyring af Futon Middleware. En oversigt over aktuelle ROF Management-løsninger er i første omgang præsenteres. Det papir, så på nogle af de udfordringer, der i [1], nemlig specifikationen af Radio......-over-Fibre (ROF) leder virksomheden funktioner, der kontrollerer futon optisk infrastruktur definition af interoperabilitet med futon Middleware og Radio Resource Management, og definitionen af ROF Management funktioner, som er tæt korreleret og integreret med radio-og optiske interface, fysiske lag algoritmer på...

  7. Adaptive multi-channel downlink assignment for overloaded spectrum-shared multi-antenna overlaid cellular networks

    KAUST Repository

    Radaydeh, Redha Mahmoud

    2012-10-19

    Overlaid cellular technology has been considered as a promising candidate to enhance the capacity and extend the coverage of cellular networks, particularly indoors. The deployment of small cells (e.g. femtocells and/or picocells) in an overlaid setup is expected to reduce the operational power and to function satisfactorily with the existing cellular architecture. Among the possible deployments of small-cell access points is to manage many of them to serve specific spatial locations, while reusing the available spectrum universally. This contribution considers the aforementioned scenario with the objective to serve as many active users as possible when the available downlink spectrum is overloaded. The case study is motivated by the importance of realizing universal resource sharing in overlaid networks, while reducing the load of distributing available resources, satisfying downlink multi-channel assignment, controlling the aggregate level of interference, and maintaining desired design/operation requirements. These objectives need to be achieved in distributed manner in each spatial space with as low processing load as possible when the feedback links are capacity-limited, multiple small-cell access points can be shared, and data exchange between access points can not be coordinated. This contribution is summarized as follows. An adaptive downlink multi-channel assignment scheme when multiple co-channel and shared small-cell access points are allocated to serve active users is proposed. It is assumed that the deployed access points employ isotropic antenna arrays of arbitrary sizes, operate using the open-access strategy, and transmit on shared physical channels simultaneously. Moreover, each active user can be served by a single transmit channel per each access point at a time, and can sense the concurrent interference level associated with each transmit antenna channel non-coherently. The proposed scheme aims to identify a suitable subset of transmit channels

  8. Influence of the Antenna Impedance Variation and Input Matching Network Q on LNA Key Figures

    DEFF Research Database (Denmark)

    Ruaro, Andrea; Kvist, Søren Helstrup; Gülstorff, Steen

    2012-01-01

    In this paper we present an analysis of the behaviour of a 2:4 GHz Low Noise Amplifier (LNA) for Wireless Body Area Network (WBAN) applications facing antennadetuning issue. An amplifier with ultra-low power, low voltage, and with reduced component count is prototyped to validate simulation resul...

  9. Radio/antenna mounting system for wireless networking under row-crop agriculture conditions

    Science.gov (United States)

    Interest in and deployment of wireless monitoring systems is increasing in many diverse environments, including row-crop agricultural fields. While many studies have been undertaken to evaluate various aspects of wireless monitoring and networking, such as electronic hardware components, data-colle...

  10. Tiny Integrated Network Analyzer for Noninvasive Measurements of Electrically Small Antennas

    DEFF Research Database (Denmark)

    Buskgaard, Emil Feldborg; Krøyer, Ben; Tatomirescu, Alexandru

    2016-01-01

    the system. The tiny integrated network analyzer is a stand-alone Arduino-based measurement system that utilizes the transmit signal of the system under test as its reference. It features a power meter with triggering ability, on-board memory, universal serial bus, and easy extendibility with general...

  11. Stability Properties of Network Diversity Multiple Access with Multiple-Antenna Reception and Imperfect Collision Multiplicity Estimation

    Directory of Open Access Journals (Sweden)

    Ramiro Samano-Robles

    2013-01-01

    Full Text Available In NDMA (network diversity multiple access, protocol-controlled retransmissions are used to create a virtual MIMO (multiple-input multiple-output system, where collisions can be resolved via source separation. By using this retransmission diversity approach for collision resolution, NDMA is the family of random access protocols with the highest potential throughput. However, several issues remain open today in the modeling and design of this type of protocol, particularly in terms of dynamic stable performance and backlog delay. This paper attempts to partially fill this gap by proposing a Markov model for the study of the dynamic-stable performance of a symmetrical and non-blind NDMA protocol assisted by a multiple-antenna receiver. The model is useful in the study of stability aspects in terms of the backlog-user distribution and average backlog delay. It also allows for the investigation of the different states of the system and the transition probabilities between them. Unlike previous works, the proposed approach considers the imperfect estimation of the collision multiplicity, which is a crucial process to the performance of NDMA. The results suggest that NDMA improves not only the throughput performance over previous solutions, but also the average number of backlogged users, the average backlog delay and, in general, the stability of random access protocols. It is also shown that when multiuser detection conditions degrade, ALOHA-type backlog retransmission becomes relevant to the stable operation of NDMA.

  12. An Application of Artificial Neural Network to Compute the Resonant Frequency of E-Shaped Compact Microstrip Antennas

    Science.gov (United States)

    Akdagli, Ali; Toktas, Abdurrahim; Kayabasi, Ahmet; Develi, Ibrahim

    2013-09-01

    An application of artificial neural network (ANN) based on multilayer perceptrons (MLP) to compute the resonant frequency of E-shaped compact microstrip antennas (ECMAs) is presented in this paper. The resonant frequencies of 144 ECMAs with different dimensions and electrical parameters were firstly determined by using IE3D(tm) software based on the method of moments (MoM), then the ANN model for computing the resonant frequency was built by considering the simulation data. The parameters and respective resonant frequency values of 130 simulated ECMAs were employed for training and the remaining 14 ECMAs were used for testing the model. The computed resonant frequencies for training and testing by ANN were obtained with the average percentage errors (APE) of 0.257% and 0.523%, respectively. The validity and accuracy of the present approach was verified on the measurement results of an ECMA fabricated in this study. Furthermore, the effects of the slots loading method over the resonant frequency were investigated to explain the relationship between the slots and resonant frequency.

  13. IT Career JumpStart An Introduction to PC Hardware, Software, and Networking

    CERN Document Server

    Alpern, Naomi J; Muller, Randy

    2011-01-01

    A practical approach for anyone looking to enter the IT workforce Before candidates can begin to prepare for any kind of certification, they need a basic understanding of the various hardware and software components used in a computer network. Aimed at aspiring IT professionals, this invaluable book strips down a network to its bare basics, and discusses this complex topic in a clear and concise manner so that IT beginners can confidently gain an understanding of fundamental IT concepts. In addition, a base knowledge has been established so that more advanced topics and technologies can be lea

  14. Starting Online: Exploring the Use of a Social Networking Site to Facilitate Transition into Higher Education

    Science.gov (United States)

    Knight, John; Rochon, Rebecca

    2012-01-01

    It has been widely recognised that transition into higher education (HE) can be challenging for incoming students. Literature identifies three main areas where students may benefit from support: social, practical and academic. This paper discusses a case study that explores the potential of a social networking environment to provide support in…

  15. Sylvan Learning Systems To Start a Network of For-Profit Universities Overseas.

    Science.gov (United States)

    Lively, Kit; Blumenstyk, Goldie

    1999-01-01

    Sylvan Learning Systems, a company best known for its tutoring and testing operations, plans to create a network of private, for-profit universities in a dozen countries overseas, at the rate of about one institution a year. The director of the U.S. Information Agency will leave his post to head the venture. The plan has received mixed reactions.…

  16. Implications of the Dynamics of the New Networked Economy for E-Business Start-Ups: The Case of Philips' Access Point.

    Science.gov (United States)

    Tovstiga, George; Fantner, Ernest J.

    2000-01-01

    Examines implications of the networked economy for e-commerce business start-ups. Revisits the notion of "value" and "value creation" in a network context. Examines "value" relative to technological innovation. Looks at implications of the network environment for the organization and transformation of the enterprise's…

  17. Antenna toolkit

    CERN Document Server

    Carr, Joseph

    2006-01-01

    Joe Carr has provided radio amateurs and short-wave listeners with the definitive design guide for sending and receiving radio signals with Antenna Toolkit 2nd edition.Together with the powerful suite of CD software, the reader will have a complete solution for constructing or using an antenna - bar the actual hardware! The software provides a simple Windows-based aid to carrying out the design calculations at the heart of successful antenna design. All the user needs to do is select the antenna type and set the frequency - a much more fun and less error prone method than using a con

  18. Antenna Calibration and Measurement Equipment

    Science.gov (United States)

    Rochblatt, David J.; Cortes, Manuel Vazquez

    2012-01-01

    A document describes the Antenna Calibration & Measurement Equipment (ACME) system that will provide the Deep Space Network (DSN) with instrumentation enabling a trained RF engineer at each complex to perform antenna calibration measurements and to generate antenna calibration data. This data includes continuous-scan auto-bore-based data acquisition with all-sky data gathering in support of 4th order pointing model generation requirements. Other data includes antenna subreflector focus, system noise temperature and tipping curves, antenna efficiency, reports system linearity, and instrument calibration. The ACME system design is based on the on-the-fly (OTF) mapping technique and architecture. ACME has contributed to the improved RF performance of the DSN by approximately a factor of two. It improved the pointing performances of the DSN antennas and productivity of its personnel and calibration engineers.

  19. Some Recent Developments of Microstrip Antenna

    Directory of Open Access Journals (Sweden)

    Yong Liu

    2012-01-01

    Full Text Available Although the microstrip antenna has been extensively studied in the past few decades as one of the standard planar antennas, it still has a huge potential for further developments. The paper suggests three areas for further research based on our previous works on microstrip antenna elements and arrays. One is exploring the variety of microstrip antenna topologies to meet the desired requirement such as ultrawide band (UWB, high gain, miniaturization, circular polarization, multipolarized, and so on. Another is to apply microstrip antenna to form composite antenna which is more potent than the individual antenna. The last is growing towards highly integration of antenna/array and feeding network or operating at relatively high frequencies, like sub-millimeter wave or terahertz (THz wave regime, by using the advanced machining techniques. To support our points of view, some examples of antennas developed in our group are presented and discussed.

  20. A neural network-based approach to noise identification of interferometric GW antennas: the case of the 40 m Caltech laser interferometer

    CERN Document Server

    Acernese, F; Rosa, M D; Rosa, R D; Eleuteri, A; Milano, L; Tagliaferri, R

    2002-01-01

    In this paper, a neural network-based approach is presented for the real time noise identification of a GW laser interferometric antenna. The 40 m Caltech laser interferometer output data provide a realistic test bed for noise identification algorithms because of the presence of many relevant effects: violin resonances in the suspensions, main power harmonics, ring-down noise from servo control systems, electronic noises, glitches and so on. These effects can be assumed to be present in all the first interferometric long baseline GW antennas such as VIRGO, LIGO, GEO and TAMA. For noise identification, we used the Caltech-40 m laser interferometer data. The results we obtained are pretty good notwithstanding the high initial computational cost. The algorithm we propose is general and robust, taking into account that it does not require a priori information on the data, nor a precise model, and it constitutes a powerful tool for time series data analysis.

  1. A neural network-based approach to noise identification of interferometric GW antennas: the case of the 40 m Caltech laser interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Acernese, F [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Barone, F [Istituto Nazionale di Fisica Nucleare, sez. Napoli, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Rosa, M de [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Rosa, R De [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Eleuteri, A [Istituto Nazionale di Fisica Nucleare, sez. Napoli, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Milano, L [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Complesso Universitario di Monte S Angelo, via Cintia, I-80126 Naples (Italy); Tagliaferri, R [Dipartimento di Matematica ed Informatica, Universita di Salerno, via S Allende, I-84081 Baronissi (Salerno) (Italy)

    2002-06-21

    In this paper, a neural network-based approach is presented for the real time noise identification of a GW laser interferometric antenna. The 40 m Caltech laser interferometer output data provide a realistic test bed for noise identification algorithms because of the presence of many relevant effects: violin resonances in the suspensions, main power harmonics, ring-down noise from servo control systems, electronic noises, glitches and so on. These effects can be assumed to be present in all the first interferometric long baseline GW antennas such as VIRGO, LIGO, GEO and TAMA. For noise identification, we used the Caltech-40 m laser interferometer data. The results we obtained are pretty good notwithstanding the high initial computational cost. The algorithm we propose is general and robust, taking into account that it does not require a priori information on the data, nor a precise model, and it constitutes a powerful tool for time series data analysis.

  2. Tracking and Data Relay Satellite System user impact and network compatibility study. [antenna design and telecommunication links

    Science.gov (United States)

    1973-01-01

    The report contains data on antenna configurations for the low data rate users of the Tracking and Data Relay Satellite System (TDRSS). It treats the coverage and mutual visibility considerations between the user satellites and the relay satellites and relates these considerations to requirements of antenna beamwidth and fractional user orbital coverage. A final section includes user/TDRS telecommunication link budgets and forward and return link data rate tradeoffs.

  3. Wide-frequency range, dynamic matching network and power system for the "Shoelace" radio frequency antenna on the Alcator C-Mod tokamak.

    Science.gov (United States)

    Golfinopoulos, Theodore; LaBombard, Brian; Burke, William; Parker, Ronald R; Parkin, William; Woskov, Paul

    2014-04-01

    A wide-frequency range (50-300 kHz) power system has been implemented for use with a new RF antenna - the "Shoelace" antenna - built to drive coherent plasma fluctuations in the edge of the Alcator C-Mod tokamak. A custom, dynamically tunable matching network allows two commercial 1 kW, 50-Ω RF amplifiers to drive the low-impedance, inductive load presented by the antenna. This is accomplished by a discretely variable L-match network, with 81 independently selected steps available for each of the series and parallel legs of the matching configuration. A compact programmable logic device provides a control system that measures the frequency with better than 1 kHz accuracy and transitions to the correct tuning state in less than 1 ms. At least 85% of source power is dissipated in the antenna across the operational frequency range, with a minimum frequency slew rate of 1 MHz/s; the best performance is achieved in the narrower band from 80 to 150 kHz which is of interest in typical experiments. The RF frequency can be run with open-loop control, following a pre-programmed analog waveform, or phase-locked to track a plasma fluctuation diagnostic signal in real time with programmable phase delay; the amplitude control is always open-loop. The control waveforms and phase delay are programmed remotely. These tools have enabled first-of-a-kind measurements of the tokamak edge plasma system response in the frequency range and at the wave number at which coherent fluctuations regulate heat and particle transport through the plasma boundary.

  4. A Network of Direct Broadcast Antenna Systems to Provide Real-Time Infrared and Microwave Sounder Data for Numerical Weather Prediction

    Science.gov (United States)

    Gumley, L.

    2013-12-01

    The Space Science and Engineering Center at the University of Wisconsin-Madison is creating a network of direct broadcast satellite data reception stations to acquire and process infrared and microwave sounder data in real-time from polar orbiting meteorological satellites and deliver the resulting products to NOAA with low latency for assimilation in NCEP numerical weather prediction models. The network will include 4 antenna sites that will be operated directly by SSEC, including Madison WI, Honolulu HI, Miami FL, and Mayaguez PR. The network will also include partner antenna sites not directly controlled by SSEC, including Corvallis OR, Monterey CA, Suitland MD, Fairbanks AK, and Guam. All of the antenna sites will have a combined X/L-band reception system capable of receiving data via direct broadcast from polar orbiting satellites including Suomi NPP and JPSS-1, Metop-A/B, POES,Terra, and Aqua. Each site will collect raw data from these satellites locally, process it to Level 1 (SDR) and Level 2 (EDR) products, and transmit the products back to SSEC for delivery to NOAA/NCEP. The primary purpose of the antenna systems is to provide real-time infrared and microwave sounder data from Metop and Suomi-NPP to NOAA to support data assimilation for NOAA/NCEP operational numerical weather prediction models. At present, NOAA/NCEP use of advanced infrared (CrIS, IASI, AIRS) and microwave (ATMS, AMSU) sounder data over North America in NWP data assimilation is limited because of the latency of the products in relation to the cutoff times for assimilation runs. This network will deliver infrared and microwave sounder data to NCEP with the lowest latency possible, via the reception and processing of data received via direct broadcast. CIMSS/SSEC is managing the procurement and installation of the antenna systems at the two new sites, and will operate the stations remotely. NOAA will establish the reception priorities (Metop and SNPP will be at the highest priority) and

  5. Antenna arraying performance for deep space telecommunications systems

    Science.gov (United States)

    Stelzried, C. T.; Berman, A. L.; Noreen, G. K.

    1983-01-01

    Antenna arraying is a crucial Deep Space Network technique in maximizing the science return of planetary and comet encounters. The equations which describe the total figure of merit for a multiple system of arrayed antennas are developed. An example is given for three Canberra DSN antennas and the Parkes 64-m antenna to be arrayed for the Voyager 2 Uranus flyby.

  6. Characterizing charge centroids from lightning using a slow antenna network and the Levenberg-Marquardt inverse method

    Science.gov (United States)

    Lapierre, J. L.; Sonnenfeld, R. G.; Hager, W. W.; Morris, K.

    2011-12-01

    Researchers have long studied the copious and complex electric field waveforms caused by lightning. By combining electric-field measurements taken at many different locations on the ground simultaneously [Krehbiel et al., 1979], we hope to learn more about charge sources for lightning flashes. The Langmuir Electric Field Array (LEFA) is a network of nine field-change measurement stations (slow-antennas) arranged around Langmuir Laboratory near Magdalena, New Mexico. Using a mathematical method called the Levenberg-Marquardt (LM) method, we can invert the electric field data to determine the magnitude and position of the charge centroid removed from the cloud. We analyzed three return strokes (RS) following a dart-leader from a storm occurring on October 21st 2011. RS 'A' occurred at 07:17:00.63 UT. The altitude of the charge centroid was estimated to be 5 km via LMA data. Because the LM method requires a prediction, the code was run with a wide range of values to verify the robustness of the method. Predictions varied from ±3 C for the charge magnitude and ±20 km N-S and E-W for the position (with the coordinate origin being the Langmuir Laboratory Annex). The LM method converged to a charge magnitude of -5.5 C and a centroid position of 3.3 km E-W and 12 km, N-S for that RS. RS 'B' occurred at 07:20:05.9 UT. With an altitude of 4 km, the predictions were again varied; ±3 C, ±15 km N-S and E-W. Most runs converged to -27.5 C, 4 km E-W, and 10.9 km N-S. Finally, while results seem best for events right over the array, success was had locating more distant events. RS 'C' occurred at 02:42:46.8 UT. Assuming an altitude of 5 km and varying the predictions as with RS 'A', the results converged to -9.2 C, 35.5 km E-W, and 9 km N-S. All of these results are broadly consistent with the LMA and the NLDN. By continuing this type of analysis, we hope to learn more about how lightning channels propagate and how the charges in the cloud respond to the sudden change in

  7. A Cold Start Context-Aware Recommender System for Tour Planning Using Artificial Neural Network and Case Based Reasoning

    Directory of Open Access Journals (Sweden)

    Zahra Bahramian

    2017-01-01

    Full Text Available Nowadays, large amounts of tourism information and services are available over the Web. This makes it difficult for the user to search for some specific information such as selecting a tour in a given city as an ordered set of points of interest. Moreover, the user rarely knows all his needs upfront and his preferences may change during a recommendation process. The user may also have a limited number of initial ratings and most often the recommender system is likely to face the well-known cold start problem. The objective of the research presented in this paper is to introduce a hybrid interactive context-aware tourism recommender system that takes into account user’s feedbacks and additional contextual information. It offers personalized tours to the user based on his preferences thanks to the combination of a case based reasoning framework and an artificial neural network. The proposed method has been tried in the city of Tehran in Iran. The results show that the proposed method outperforms current artificial neural network methods and combinations of case based reasoning with k-nearest neighbor methods in terms of user effort, accuracy, and user satisfaction.

  8. Circularly polarized antennas

    CERN Document Server

    Gao, Steven; Zhu, Fuguo

    2013-01-01

    This book presents a comprehensive insight into the design techniques for different types of CP antenna elements and arrays In this book, the authors address a broad range of topics on circularly polarized (CP) antennas. Firstly, it introduces to the reader basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antennas (QHA), printed quadrifilar helix antennas (PQHA), spiral antenna, CP slot antennas, CP dielectric resonator antennas, loop antennas, crossed dipoles, monopoles and CP horns. Adva

  9. Antenna theory and practice

    Science.gov (United States)

    Chatterjee, Rajeswari

    The fundamental operating principles and applications of antennas are examined in an introductory textbook for undergraduate engineering students. The theory of EM fields and radiation is reviewed, and consideration is given to thin linear, cylindrical, and biconical antennas; antenna arrays; loop, helical, slot, microstrip, horn, reflector, and lens antennas; leaky-wave and surface-wave antennas; dielectric and dielectric-loaded metallic antennas; and wideband antennas. Also discussed are antenna synthesis, practical antennas for different wavebands, antenna measurements, EM wave propagation, and problems in antenna design. Diagrams, drawings, graphs, and sample problems are provided.

  10. Metamaterial-inspired SRR-based Small Antenna

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2009-01-01

    A self-resonant miniaturized antenna composed of a broadside-coupled split ring resonator (SRR) and an excitation truncated loop is presented. Being λ0/17 in size the antenna is tuned to 50 Ohms without any matching network.......A self-resonant miniaturized antenna composed of a broadside-coupled split ring resonator (SRR) and an excitation truncated loop is presented. Being λ0/17 in size the antenna is tuned to 50 Ohms without any matching network....

  11. Metamaterial-Inspired Efficient Electrically Small Antenna

    DEFF Research Database (Denmark)

    Erentok, Aycan; Ziolkowski, R. W.

    2008-01-01

    Planar two-dimensional (2D) and volumetric three-dimensional (3D) metamaterial-inspired efficient electrically-small antennas that are easy to design; are easy and inexpensive to build; and are easy to test; are reported, i.e., the EZ antenna systems. The proposed 2D and 3D electrical- and magnetic......-based EZ antennas are shown to be naturally matched to a 50 source, i.e., without the introduction of a matching network. It is demonstrated numerically that these EZ antennas have high radiation efficiencies with very good impedance matching between the source and the antenna and, hence, that they have...... high overall efficiencies. The reported 2D and 3D EZ antenna designs are linearly scalable to a wide range of frequencies and yet maintain their easy-to-build characteristics. Several versions of the 2D EZ antennas were fabricated and tested. The measurement results confirm the performance predictions...

  12. Independent Peer Review of Communications, Navigation, and Networking re-Configurable Testbed (CoNNeCT) Project Antenna Pointing Subsystem (APS) Integrated Gimbal Assembly (IGA) Structural Analysis

    Science.gov (United States)

    Raju, Ivatury S.; Larsen, Curtis E.; Pellicciotti, Joseph W.

    2010-01-01

    Glenn Research Center Chief Engineer's Office requested an independent review of the structural analysis and modeling of the Communications, Navigation, and Networking re-Configurable Testbed (CoNNeCT) Project Antenna Pointing Subsystem (APS) Integrated Gimbal Assembly (IGA) to be conducted by the NASA Engineering and Safety Center (NESC). At this time, the IGA had completed its critical design review (CDR). The assessment was to be a peer review of the NEi-NASTRAN1 model of the APS Antenna, and not a peer review of the design and the analysis that had been completed by the GRC team for CDR. Thus, only a limited amount of information was provided on the structural analysis. However, the NESC team had difficulty separating analysis concerns from modeling issues. The team studied the NASTRAN model, but did not fully investigate how the model was used by the CoNNeCT Project and how the Project was interpreting the results. The team's findings, observations, and NESC recommendations are contained in this report.

  13. Combined Calibration Method and its Realization for Direction Finding Antenna Systems with Patch Antennas

    Directory of Open Access Journals (Sweden)

    R. Seller

    2007-09-01

    Full Text Available A novel radio channel compensation method aiming to give optimal calibration for microstrip antenna array systems is presented in this paper, realized for an actual DOA measurement antenna system using microstrip antennas to sample the electromagnetic field, operating at 4.5GHz. This new approach considers mismatch between antennas and channel RF ports, channel transmission inequalities, and also decreases the effects of multipath propagation components of calibration reference signals by placing the calibration reference signal feeding network on the microstrip antenna array bearer, directly beside the antenna patches. It is combined with orthogonal spread spectrum calibration signal utility for continuous uninterrupted measurements. The spread spectrum calibration signal is orthogonal to the continuous wave (CW signal to be measured, therefore, the 2 signals can be separated in the receiver, enabling them to be present simultaneously. DOA measurement results are shown, measured with the realized integrated microstrip patch antenna array with calibration network hardware.

  14. An Adaptive B-Spline Neural Network and Its Application in Terminal Sliding Mode Control for a Mobile Satcom Antenna Inertially Stabilized Platform

    Science.gov (United States)

    Zhang, Xiaolei; Zhao, Yan; Guo, Kai; Li, Gaoliang; Deng, Nianmao

    2017-01-01

    The mobile satcom antenna (MSA) enables a moving vehicle to communicate with a geostationary Earth orbit satellite. To realize continuous communication, the MSA should be aligned with the satellite in both sight and polarization all the time. Because of coupling effects, unknown disturbances, sensor noises and unmodeled dynamics existing in the system, the control system should have a strong adaptability. The significant features of terminal sliding mode control method are robustness and finite time convergence, but the robustness is related to the large switching control gain which is determined by uncertain issues and can lead to chattering phenomena. Neural networks can reduce the chattering and approximate nonlinear issues. In this work, a novel B-spline curve-based B-spline neural network (BSNN) is developed. The improved BSNN has the capability of shape changing and self-adaption. In addition, the output of the proposed BSNN is applied to approximate the nonlinear function in the system. The results of simulations and experiments are also compared with those of PID method, non-singularity fast terminal sliding mode (NFTSM) control and radial basis function (RBF) neural network-based NFTSM. It is shown that the proposed method has the best performance, with reliable control precision. PMID:28452931

  15. An Adaptive B-Spline Neural Network and Its Application in Terminal Sliding Mode Control for a Mobile Satcom Antenna Inertially Stabilized Platform.

    Science.gov (United States)

    Zhang, Xiaolei; Zhao, Yan; Guo, Kai; Li, Gaoliang; Deng, Nianmao

    2017-04-28

    The mobile satcom antenna (MSA) enables a moving vehicle to communicate with a geostationary Earth orbit satellite. To realize continuous communication, the MSA should be aligned with the satellite in both sight and polarization all the time. Because of coupling effects, unknown disturbances, sensor noises and unmodeled dynamics existing in the system, the control system should have a strong adaptability. The significant features of terminal sliding mode control method are robustness and finite time convergence, but the robustness is related to the large switching control gain which is determined by uncertain issues and can lead to chattering phenomena. Neural networks can reduce the chattering and approximate nonlinear issues. In this work, a novel B-spline curve-based B-spline neural network (BSNN) is developed. The improved BSNN has the capability of shape changing and self-adaption. In addition, the output of the proposed BSNN is applied to approximate the nonlinear function in the system. The results of simulations and experiments are also compared with those of PID method, non-singularity fast terminal sliding mode (NFTSM) control and radial basis function (RBF) neural network-based NFTSM. It is shown that the proposed method has the best performance, with reliable control precision.

  16. Normal heights for GNSS reference station antennas

    Science.gov (United States)

    Balodis, J.; Morozova, K.; Reiniks, M.; Normand, M.

    2017-10-01

    The GNSS reference station ellipsoidal heights are of the mm precision quality due to their continuous operation and monitoring of their coordinates in the international terrestrial reference frame. The GNSS reference station data is mostly used for rover positioning. The reference stations are very important also as a fitting points for the geoid modelling developments. Unfortunately, the importance of the referencing of antenna heights to the national levelling network are sometimes neglected. Usually the antennas are fixed on the roof of high buildings in urban environment. It is quite difficult to make a high precision levelling procedures and sometimes the direct geodetic measurements of antenna normal heights are not performed. Actually, for the most of Latvian GNSS reference network antennas the normal heights are not tied to the national levelling network. The aim of this research is to use the collected data of GNSS/levelling points for the determination of the normal heights of continuously operating reference station antennas.

  17. Fano Bounds for Compact Antennas. Phase I

    Science.gov (United States)

    2007-10-01

    Sons. [4] Balabanian, Norman & Theodore A. Bickart [1981] Linear Network The- ory, Matrix Publishers, Inc., Beaverton, OR. [5] Carlin, Herbert J...Systems with Coupled Antennas and Noisy Amplifiers, IEEE Transactions on Antennas and Propagation, 53(1), pages 545–552. [19] Newcomb , Robert W. [1966

  18. Superluminal antenna

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, John; Earley, Lawrence M.; Krawczyk, Frank L.; Potter, James M.; Romero, William P.; Wang, Zhi-Fu

    2017-03-28

    A superluminal antenna element integrates a balun element to better impedance match an input cable or waveguide to a dielectric radiator element, thus preventing stray reflections and consequent undesirable radiation. For example, a dielectric housing material can be used that has a cutout area. A cable can extend into the cutout area. A triangular conductor can function as an impedance transition. An additional cylindrical element functions as a sleeve balun to better impedance match the radiator element to the cable.

  19. Novel Electrically Small Spherical Electric Dipole Antenna

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2010-01-01

    This paper introduces a novel electrically small spherical meander antenna. Horizontal sections of the meander are composed of wire loops, radii of which are chosen so that the whole structure is conformal to a sphere of radius a. To form the meander the loops are connected by wires at a meridian...... plane. The antenna operates as an electric dipole, i.e. it radiates the TM10 spherical mode. The antenna is self-resonant and can be matched to a wide range of input feed lines without an external matching network. In this paper, a spherical meander antenna of the size ka = 0.27 and the input impedance...

  20. Miniaturized Planar Split-Ring Resonator Antenna

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2009-01-01

    A miniaturized planar antenna based on a broadside-coupled split ring resonator excited by an arc-shaped dipole is presented. The excitation dipole acts as a small tuning capacitor in series with a parallel RLC circuit represented by the SRR. The antenna resonance frequency and dimensions...... a essentially determined by the SRR, while by varying the dipole arm length the input resistance is changed in a wide range, thus matching the antenna to a feed line and compensating for simulation and manufacturing inaccuracies. No additional matching network is required. Theoretically, there is no limit...... on how small this antenna can be. In practice, the lower bound is set by losses in utilized materials and manufacturing inaccuracies. As an example, an antenna of ka=0.09 was designed, fabricated and tested. Although the initially fabricated antenna prototype had the input impedance of 43 ohms...

  1. Beamforming and Antenna Grouping Design for the Multi-Antenna Relay with Energy Harvesting to Improve Secrecy Rate

    Directory of Open Access Journals (Sweden)

    Weijia Lei

    2016-07-01

    Full Text Available The physical security strategy in the wireless network with a single-antenna eavesdropper is studied. The information transmits from a single-antenna source to a single-antenna destination, and an energy-limited multi-antenna relay is employed to forward information. The antennas of the relay are divided into two groups. One group receives and forwards information, and the other converts the received signal into energy. Beamforming is used by the relay to prevent the eavesdropper from intercepting confidential information. For the purpose of maximizing the secrecy rate, antenna grouping and beamforming vectors are designed. A low complexity scheme of antenna grouping is presented. The simulation results show that the secrecy rate can be significantly improved by arranging part of the antennas for energy harvesting, and part for forwarding and optimizing the beamforming vector at the relay. The antenna grouping scheme significantly reduces the computational complexity at the cost of acceptable performance loss.

  2. Antennas in inhomogeneous media

    CERN Document Server

    Galejs, Janis; Fock, V A; Wait, J R

    2013-01-01

    Antennas in Inhomogeneous Media details the methods of analyzing antennas in such inhomogeneous media. The title covers the complex geometrical configurations along with its variational formulations. The coverage of the text includes various conditions the antennas are subjected to, such as antennas in the interface between two media; antennas in compressible isotropic plasma; and linear antennas in a magnetoionic medium. The selection also covers insulated loops in lossy media; slot antennas with a stratified dielectric or isotropic plasma layers; and cavity-backed slot antennas. The book wil

  3. A truncation method for modelling effective antenna patterns in urban areas

    NARCIS (Netherlands)

    Mantel, O.C.; Rijken, M.; Matic, D.; Mawira, A.

    2004-01-01

    Signal level predictions for sector antennas in mobile networks strongly depend on the antenna pattern used in the prediction tool. For built-up areas, reflections and scattering often lead to a significant energy component at the back of the antenna, and the theoretical antenna pattern does not

  4. Mobile Phone Antenna Performance 2016

    DEFF Research Database (Denmark)

    Pedersen, Gert F.

    This study investigates the antenna performance of a number of mobile phones widely used in the Nordic Countries. The study is supported by the Nordic Council of Ministers. The antenna performance of the phones is vital for the phones ability to ensure radio coverage in low signal situations....... The study is based on the mobile systems in the Nordic mobile networks and on both speech and data services. The selected phone models are among the most popular new phones at the time of this study....

  5. A scalable-low cost architecture for high gain beamforming antennas

    KAUST Repository

    Bakr, Omar

    2010-10-01

    Many state-of-the-art wireless systems, such as long distance mesh networks and high bandwidth networks using mm-wave frequencies, require high gain antennas to overcome adverse channel conditions. These networks could be greatly aided by adaptive beamforming antenna arrays, which can significantly simplify the installation and maintenance costs (e.g., by enabling automatic beam alignment). However, building large, low cost beamforming arrays is very complicated. In this paper, we examine the main challenges presented by large arrays, starting from electromagnetic and antenna design and proceeding to the signal processing and algorithms domain. We propose 3-dimensional antenna structures and hybrid RF/digital radio architectures that can significantly reduce the complexity and improve the power efficiency of adaptive array systems. We also present signal processing techniques based on adaptive filtering methods that enhance the robustness of these architectures. Finally, we present computationally efficient vector quantization techniques that significantly improve the interference cancellation capabilities of analog beamforming architectures. © 2010 IEEE.

  6. Highly Compact Composite Antenna

    OpenAIRE

    Pigeon, Mélusine; Morlaas-Courties, Christophe; Aubert, Hervé; Souny, Bernard

    2009-01-01

    International audience; The highly compact antenna proposed in this communication consists of a judicious association of equivalent magnetic current source with equivalent electric current source. This composite antenna presents a directivity radiation pattern analogous to one of the microstrip ceramic antennas but can be used at low frequencies. The antenna measurements confirm the promising performances obtained from electromagnetic simulations.

  7. After Shaking his hand, start counting your fingers. Trust and Images in Indian business networks, East Africa 1900-2000

    NARCIS (Netherlands)

    G. Oonk (Gijsbert)

    2004-01-01

    textabstractIn this study I examine how ‘ethnic’ trading networks are created and recreated, but may also fracture and fall apart. This occurred among some Indian groups in East Africa, who initially strengthened their economic and cultural ties with India by maintaining intensive trade relations

  8. MIMO wireless networks channels, techniques and standards for multi-antenna, multi-user and multi-cell systems

    CERN Document Server

    Clerckx, Bruno

    2013-01-01

    This book is unique in presenting channels, techniques and standards for the next generation of MIMO wireless networks. Through a unified framework, it emphasizes how propagation mechanisms impact the system performance under realistic power constraints. Combining a solid mathematical analysis with a physical and intuitive approach to space-time signal processing, the book progressively derives innovative designs for space-time coding and precoding as well as multi-user and multi-cell techniques, taking into consideration that MIMO channels are often far from ideal. Reflecting developments

  9. Matching Parasitic Antenna for Single RF MIMO

    DEFF Research Database (Denmark)

    Han, Bo; Kalis, A; Nielsen, Rasmus Hjorth

    2012-01-01

    Single RF MIMO communication emerges a novel low cost communication method which does not consume as much power as the conventional MIMO. The implementation of such single RF MIMO system is done by mapping the weighting factors to the polarizations or the radiation patterns of the antennas....... In order to have such performance, an antenna with rich pattern modes is required by the system, thus the ESPAR antenna is investigated. The critical part on such antenna is parasitic element impedance matching. Unlike the conventional smith-chart matching method which assumes the minimal resistance...... is zero and with goal of 50 ohm or 75 ohm matching, matching on such parasitic antenna will adopt negative value as well. This paper presents a matching network with controllable impedance even to the range of negative values....

  10. A metamolecule antenna for coplanar waveguides.

    Science.gov (United States)

    Maple, L C; Berry, S A; Stenning, G B G; Bowden, G J; de Groot, P A J; Apostolopoulos, V

    2014-12-15

    We report on a metamolecule antenna, based on a fish-scale design but augmented with two split-ring resonators (SRRs) placed within the fish-scale loops. The properties of the antenna resonator, with and without additional SRRs, were examined using finite element method simulations (COMSOL Multiphysics). The simulation findings were subsequently confirmed experimentally, using a vector network analyser coupled to an antenna-loaded coplanar waveguide (CPW). The addition of SRRs to the fish-scale meta-molecule leads to a demonstrably large increase in microwave-absorption. It is shown that the fish-scale/SRR/CPW combination performs as a microwave antenna. Simulations of the antenna gain and far-field emission are presented and discussed.

  11. Wideband Monopole Fractal Heptagonal Antenna Implementation in X-Band Frequency Range

    Science.gov (United States)

    Iqbal, Muhammad Naeem; Ur-Rahman, Hamood; Tauqeer, T.; Ramer, Rodica

    2017-10-01

    A wideband heptagonal fractal monopole antenna with coplanar waveguide feed is designed and fabricated in X-band frequency range. Comparison of heptagonal fractal monopole antennas with two different substrates to achieve optimum efficiency for UWB applications is presented. FR4 and RT/Duroid 5880 substrates are used for antenna design and fabrication. Four iterations of base shape are used. Fractal antenna has omni-directional radiation pattern. Simulated and measured results showed that monopole fractal antenna with RT/Duroid 5880 substrate has better performance than fractal antenna with FR4 substrate in terms of bandwidth and return loss. Major application area of proposed antenna is wireless body area networks.

  12. to start

    Indian Academy of Sciences (India)

    Click here to start. Table of contents. Slide 1 · Slide 2 · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Slide 8 · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Slide 15 · Slide 16 · Slide 17 · Slide 18 · Slide 19.

  13. Integrated Solar-Panel Antenna Array for CubeSats

    Science.gov (United States)

    Baktur, Reyhan

    2016-01-01

    The goal of the Integrated Solar-Panel Antenna Array for CubeSats (ISAAC) project is to design and demonstrate an effective and efficien toptically transparent, high-gain, lightweight, conformal X-band antenna array that is integrated with the solar panels of a CubeSat. The targeted demonstration is for a Near Earth Network (NEN)radio at X-band, but the design can be easilyscaled to other network radios for higher frequencies. ISAAC is a less expensive and more flexible design for communication systemscompared to a deployed dish antenna or the existing integrated solar panel antenna design.

  14. Design of an Antenna Measurement System

    Science.gov (United States)

    Patel, Kyle

    Modern communication systems require next generation antenna, whose performance can only be verified through specialized equipment and methodology. For example, a vector network analyzer can be used to determine metrics such as the impedance bandwidth of an antenna. However, a vector network analyzer provides only a portion of the operational characteristics of an antenna. Instead, controlled environments known as anechoic chambers are used to ascertain the radiation characteristics of an antenna under test. These facilities typically incorporate a variety of different instruments to facilitate the measurement process. Rotary tables, linear actuators, vector network analyzers, and amplifiers are examples of typical components that are used in an anechoic chamber. While one could certainly manually control these components, it is more efficient to automate the measurement procedure. This saves time and increases repeatability of measurements. This thesis presents a complete software design for automated antenna measurement system for use in anechoic chambers. This developed software is both modular and flexible, which allows for easy adaptation for new equipment over time and allows the system to run in a simulation mode if some hardware components are not present. The system has also proven its capability by successfully measuring the radiation pattern of a dipole antenna, even in an anechoic chamber lacking wall-to-wall absorbers.

  15. [Microstrip antenna design and system research of radio frequency identification temperature sensor].

    Science.gov (United States)

    Yang, Hao; Yang, Xiaohe; Chen, Yuquan; Pan, Min

    2008-12-01

    Radio frequency identification sensor network, which is a product of integrating radio frequency identification (RFID) with wireless sensor network (WSN), is introduced in this paper. The principle of radio frequency identification sensor is analyzed, and the importance of the antenna is emphasized. Then three kinds of common antennae, namely coil antenna, dipole antenna and microstrip antenna, are discussed. Subsequently, according to requirement, we have designed a microstrip antenna in a wireless temperature-monitoring and controlling system. The measurement of factual effect showed the requirement was fulfilled.

  16. Joint ACE ground penetrating radar antenna test facility at the Technical University of Denmark

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter; Sarri, A.

    2005-01-01

    A ground penetrating radar (GPR) antenna test facility, established within the ACE network at the Technical University of Denmark (DTU), is described. Examples of results from the facility obtained from measurements of eight different GPR antennas are presented.......A ground penetrating radar (GPR) antenna test facility, established within the ACE network at the Technical University of Denmark (DTU), is described. Examples of results from the facility obtained from measurements of eight different GPR antennas are presented....

  17. Synthesis of an aperiodic antenna array - Application to microstrip antennas

    Science.gov (United States)

    Mekkioui, Zahera; Bendimerad, Fethi-Tarik

    1992-10-01

    Several methods for synthesizing aperiodic arrays are proposed with application to microstrip antennas. Their particular feature is to take into account the field pattern issued by the primary source. By stating the feed law and by acting solely on the position parameter we are able to make the radiation pattern of the antenna array conform to a number of given requirements. The duplication of the spatial distribution sets constraints linked to the criteria for nonoverlapping sources. Starting with two different formulations regarding the problem of synthesis we propose two solution techniques: minimax (top down based on subgradient) and relaxation under constraints. The various methods are compared and an extension to a plane array is derived.

  18. The solar probe antenna

    Science.gov (United States)

    Imbriale, W. A.; Randolph, J. E.; Embuido, E.

    2004-01-01

    This paper details the design of the antenna intended for use on the Solar Probe Mission. The antenna consists of a carbon-carbon reflector jointly used as the antenna and thermal shield and helical feed using tungsten wire and ceramic matrix composite (CMC) materials for the back plate, coaxial cable waveguide. A complete prototype feed assembly was fabricated and tested.

  19. Height dependence of antenna factors of antennas for disturbance measurement

    Science.gov (United States)

    Tejima, Teruo; Harima, Katsushige; Koike, Kunimasa; Masuzawa, Hiroshi

    1995-06-01

    This paper investigates the height dependence of various antenna factors for tuned-dipole antennas, shortened-dipole antennas and the biconical antennas commonly used for electro-magnetic disturbance measurements from 30 MHz to 300 MHz. This height dependence is measured by the three-antenna method at an open-field-test site. Our results indicate tuned-dipole antenna strongly depend on antenna height, and biconical antenna depend on antenna height above 75 MHz. This study is based on the assumption that the antennas are properly calibrated.

  20. Press Start

    Science.gov (United States)

    Harteveld, Casper

    This level sets the stage for the design philosophy called “Triadic Game Design” (TGD). This design philosophy can be summarized with the following sentence: it takes two to tango, but it takes three to design a meaningful game or a game with a purpose. Before the philosophy is further explained, this level will first delve into what is meant by a meaningful game or a game with a purpose. Many terms and definitions have seen the light and in this book I will specifically orient at digital games that aim to have an effect beyond the context of the game itself. Subsequently, a historical overview is given of the usage of games with a serious purpose which starts from the moment we human beings started to walk on our feet till our contemporary society. It turns out that we have been using games for all kinds of non-entertainment purposes for already quite a long time. With this introductory material in the back of our minds, I will explain the concept of TGD by means of a puzzle. After that, the protagonist of this book, the game Levee Patroller, is introduced. Based on the development of this game, the idea of TGD, which stresses to balance three different worlds, the worlds of Reality, Meaning, and Play, came into being. Interested? Then I suggest to quickly “press start!”

  1. to start

    Indian Academy of Sciences (India)

    Click here to start. Table of contents. Slide 1 · Slide 2 · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Slide 8 · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Slide 15 · Slide 16 · Slide 17 · Slide 18 · Slide 19 · Slide 20 · Slide 21 · Slide 22 · Slide 23 · Slide 24 · Slide 25 · Slide 26 · Slide 27 · Slide 28 · Slide 29 · Slide 30.

  2. Starting electronics

    CERN Document Server

    Brindley, Keith

    2005-01-01

    Starting Electronics is unrivalled as a highly practical introduction for hobbyists, students and technicians. Keith Brindley introduces readers to the functions of the main component types, their uses, and the basic principles of building and designing electronic circuits. Breadboard layouts make this very much a ready-to-run book for the experimenter; and the use of multimeter, but not oscilloscopes, puts this practical exploration of electronics within reach of every home enthusiast's pocket. The third edition has kept the simplicity and clarity of the original. New material

  3. Novel Microstrip Patch Antennas with Frequency Agility, Polarization Reconfigurability, Dual Null Steering Capability and Phased Array Antenna with Beam Steering Performance

    Science.gov (United States)

    Babakhani, Behrouz

    Nowadays the wireless communication technology is playing an important role in our daily life. People use wireless devices not only as a conventional communication device but also as tracking and navigation tool, web browsing tool, data storage and transfer tool and so for many other reasons. Based on the user demand, wireless communication engineers try to accommodate as many as possible wireless systems and applications in a single device and therefore, creates a multifunctional device. Antenna, as an integral part of any wireless communication systems, should also be evolved and adjusted with development of wireless transceiver systems. Therefore multifunctional antennas have been introduced to support and enhance the functionality on modern wireless systems. The main focus and contribution of this thesis is design of novel multifunctional microstrip antennas with frequency agility, polarization reconfigurablity, dual null steering capability and phased array antenna with beam steering performance. In this thesis, first, a wide bandwidth(1.10 GHz to 1.60 GHz) right-handed circularly polarized (RHCP) directional antenna for global positioning system (GPS) satellite receive application has been introduced which covers all the GPS bands starting from L1 to L5. This design consists of two crossed bow-tie dipole antennas fed with sequentially phase rotated feed network backed with an artificial high impedance surface (HIS) structure to generate high gain directional radiation patterns. This design shows good CP gain and axial ratio (AR) and wide beamwidth performance. Although this design has good radiation quality, the size and the weight can be reduced as future study. In the second design, a frequency agile antenna was developed which also covers the L-band (L1 to L5) satellite communication frequencies. This frequency agile antenna was designed and realized by new implementation of varactor diodes in the geometry of a circular patch antenna. Beside wide frequency

  4. Phase shifter for antenna beam steering

    Energy Technology Data Exchange (ETDEWEB)

    Jindal, Ravi, E-mail: rjindal21@gmail.com [Master’s(MS) in System Electronics and General Electrical, Ecole Polytechnique of university of Nantes France, IETR, Nantes (France); Razban, Tchanguiz, E-mail: tchanguiz.razban-haghighi@univ-nantes.fr [Electronics and Telecommunication Institute of Rennes (IETR-UMR 6164), Ecole Polytechnique of university of Nantes France, IETR, Nantes (France)

    2016-03-09

    Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.

  5. Visualization of electromagnetic exposure near LTE antennae

    Science.gov (United States)

    Zvezdina, M. Yu; Shokova, Yu A.; Nazarova, O. Yu; Al-Ali, H. T. A.; Al-Farhan, G. H. A.

    2018-01-01

    Technical progress in wireless data transfer has given an opportunity to apply information and communication technologies in various areas of economics. Digital economy is linked to the 4th and 5th generation mobile network deployment. The peculiarities of the abovementioned standards decrease BTS antenna range three times in dense developed areas and worsen electromagnetic background in big cities. In the paper the comparative assessment results for rooftop electromagnetic exposure near BTS LTE and BTS GSM antennae are given. It is shown, that at the same level of transmitter power, energy flux density for LTE standard is three times less than the one for GSM. Moreover, the conclusion is made that the rooftop could be considered safe for people for indefinite time if antenna is placed more than 5 meters above the rooftop. The value of antenna height is taken to be on the safe side, as it is required by an application of “preventive principle”.

  6. Microwave RF antennas and circuits nonlinearity applications in engineering

    CERN Document Server

    Aluf, Ofer

    2017-01-01

    This book describes a new concept for analyzing RF/microwave circuits, which includes RF/microwave antennas. The book is unique in its emphasis on practical and innovative microwave RF engineering applications. The analysis is based on nonlinear dynamics and chaos models and shows comprehensive benefits and results. All conceptual RF microwave circuits and antennas are innovative and can be broadly implemented in engineering applications. Given the dynamics of RF microwave circuits and antennas, they are suitable for use in a broad range of applications. The book presents analytical methods for microwave RF antennas and circuit analysis, concrete examples, and geometric examples. The analysis is developed systematically, starting with basic differential equations and their bifurcations, and subsequently moving on to fixed point analysis, limit cycles and their bifurcations. Engineering applications include microwave RF circuits and antennas in a variety of topological structures, RFID ICs and antennas, micros...

  7. Dielectrically Loaded Biconical Antennas

    Science.gov (United States)

    Nusseibeh, Fouad Ahmed

    1995-01-01

    Biconical antennas are of great interest to those who deal with broadband applications including the transmission/reception of pulses. In particular, wide-angle conical antennas are an attractive choice in many applications including Electronic Support Measures (ESM) and the measurements of transient surface currents and charge densities on aircraft. Dielectric loading in the interior region of a conical antenna can be used to reduce the size of the antenna especially at low frequencies and/or for structural strength. Therefore, having an analytical solution for the input impedance and the frequency response is very helpful in optimizing the design and understanding the behavior of the antenna. From the quasi-analytical solution for the input impedance and the electric field of a wide-angle conical antenna, it can be seen that the dielectric loading in the antenna region improves the input impedance at low frequencies, but increases the number of resonance points and the magnitude of these peaks. When an inhomogeneous dielectric load is used, the magnitude of the resonance peaks is decreased (depending on the way the load is distributed), improving the input impedance of the antenna significantly. Introducing a dielectric load in the interior region of an electrically short receiving cone makes the antenna behave as an electrically longer antenna. However, this is not true for the case for electrical1y long antennas. For the case of pulse transmission, the dielectric load affects only the amplitude. Of course, if the dielectric fills the whole space, both transmitting and receiving antennas behave as electrically longer antennas.

  8. Absolute Antenna Calibration at the US National Geodetic Survey

    Science.gov (United States)

    Mader, G. L.; Bilich, A. L.

    2012-12-01

    Geodetic GNSS applications routinely demand millimeter precision and extremely high levels of accuracy. To achieve these accuracies, measurement and instrument biases at the centimeter to millimeter level must be understood. One of these biases is the antenna phase center, the apparent point of signal reception for a GNSS antenna. It has been well established that phase center patterns differ between antenna models and manufacturers; additional research suggests that the addition of a radome or the choice of antenna mount can significantly alter those a priori phase center patterns. For the more demanding GNSS positioning applications and especially in cases of mixed-antenna networks, it is all the more important to know antenna phase center variations as a function of both elevation and azimuth in the antenna reference frame and incorporate these models into analysis software. Determination of antenna phase center behavior is known as "antenna calibration". Since 1994, NGS has computed relative antenna calibrations for more than 350 antennas. In recent years, the geodetic community has moved to absolute calibrations - the IGS adopted absolute antenna phase center calibrations in 2006 for use in their orbit and clock products, and NGS's CORS group began using absolute antenna calibration upon the release of the new CORS coordinates in IGS08 epoch 2005.00 and NAD 83(2011,MA11,PA11) epoch 2010.00. Although NGS relative calibrations can be and have been converted to absolute, it is considered best practice to independently measure phase center characteristics in an absolute sense. Consequently, NGS has developed and operates an absolute calibration system. These absolute antenna calibrations accommodate the demand for greater accuracy and for 2-dimensional (elevation and azimuth) parameterization. NGS will continue to provide calibration values via the NGS web site www.ngs.noaa.gov/ANTCAL, and will publish calibrations in the ANTEX format as well as the legacy ANTINFO

  9. Miniaturised self-resonant split-ring resonator antenna

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2009-01-01

    A self-resonant miniaturized antenna composed of a broadside-coupled split-ring resonator (SRR) and an excitation arc-shaped monopole is presented. The size of the antenna and its resonance frequency is essentially defined by the SRR dimensions and geometry, while the input resistance...... at the resonance is governed by the arc length of the monopole. Numerical and experimental results are presented for an antenna configuration of 1/23.4 wavelength in diameter (ka~0.134). The antenna is tuned to 50 ohms without any matching network, and its efficiency is measured to be 17.5%....

  10. Design of a Broadband Inverted Conical Quadrifilar Helix Antenna

    Directory of Open Access Journals (Sweden)

    Jingyan Mo

    2016-01-01

    Full Text Available This paper introduces the design of a broadband inverted conical circularly polarized quadrifilar helix antenna (QHA. The antenna has many good characteristics, including wide beam and broad bandwidth, which are achieved by utilizing inverted conical geometry and adjusting the dimensions of the inverted conical support. The antenna is fed by a wideband network to provide 90° phase difference between the four arms with constant amplitude. The antenna impedance and axial ratio bandwidth values are more than 39% and 31.5%, respectively. The measured results coincide well with the simulated ones, which verified the effectiveness of the proposed design.

  11. Broadband Monopole Antenna

    Science.gov (United States)

    2017-09-14

    whose dominant axis is aligned with the z direction, the axis of the antenna inside. The material is indicated as having multiple resonances with at...least one resonance above that of the uncoated monopole. In this antenna, the diameter of the engineered material cylinder is much smaller than the... ground plane Attorney Docket No. 300161 3 of 13 that includes a monopole extending perpendicularly from the ground plane. The antenna feed is

  12. Highly decoupled cosited antennas

    Science.gov (United States)

    Campbell, Donn V.; Dubowicz, Palemon W.; Hoverter, Robert T.

    1986-08-01

    Two cosited omnidirectional biconical antennas are respectively tilted plus and minus 45 degrees (+ or - 45 deg.) with respect to the vertical and, therefore, are perpendicular (90 deg.) with respect to each other to effect polarization mismatch and near field decoupling. In combination with the described antennae orientation, high impedance cable chokes are added in series with the coaxial cable antennae feed lines to suppress induced parasitic RF currents.

  13. Compact Antenna Range

    Data.gov (United States)

    Federal Laboratory Consortium — Facility consists of a folded compact antenna range including a computer controlled three axis position table, parabolic reflector and RF sources for the measurement...

  14. Tunable Handset Antenna

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Foroozanfard, Ehsan; Morris, Art

    2017-01-01

    With the future LTE auction for TV white spaces at 600 MHz, there is a strong need for efficient handset antennas operating at very low frequencies. This paper shows a tunable antenna covering the LTE bands from 600 MHz to 2.6 GHz. The antenna uses state-of-the-art MEMS tunable capacitors in order...... to reconfigure its operating frequency. In this work, the design mitigates the tuning loss with a tunable extended ground plane. The resulting dual-resonant antenna exhibits a peak total efficiency of -3.9 dB at 600 MHz....

  15. Tunable Handset Antenna

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Foroozanfard, Ehsan; Morris, Art

    2017-01-01

    With the future LTE auction for TV white spaces at 600 MHz, there is a strong need for efficient handset antennas operating at very low frequencies. This paper shows a tunable antenna covering the LTE bands from 600 MHz to 2.6 GHz. The antenna uses state-of-the-art MEMS tunable capacitors in orde...... to reconfigure its operating frequency. In this work, the design mitigates the tuning loss with a tunable extended ground plane. The resulting dual-resonant antenna exhibits a peak total efficiency of -3.9 dB at 600 MHz....

  16. Wide sector coverage antennas

    Science.gov (United States)

    Yaw, D. F.

    1984-09-01

    The general design and performance characteristics of transmit and receive antennas that are currently used in electronic warfare systems are reviewed. Among transmit antennas, three-to-one bandwidth, asymmetric-beam, and circularly polarized horns are discussed, as are extremely broadband monopoles and spiral antennas. In a discussion of receive antennas, attention is given to flat and conical spirals, including cavity-backed flat spirals operating over the 2.5-18 GHz range; log periodic dipoles; and biconical horns. Finally, the design configurations and performance of interferometer direction-finding systems are briefly discussed.

  17. MSU Antenna Pattern Data

    Science.gov (United States)

    Mo, Tsan; Kleespies, Thomas J.; Green, J. Philip

    2000-01-01

    The Microwave Sounding Unit (MSU) antenna pattern data for nine MSU Flight Models (FMs) have been successfully rescued from 22-year old 7-track and 9-track magnetic tapes and cartridges. These antenna pattern data were unpacked into user-friendly ASCII format, and are potentially useful for making antenna pattern corrections to MSU antenna temperatures in retrieving the true brightness temperatures. We also properly interpreted the contents of the data and show how to convert the measured antenna signal amplitude in volts into relative antenna power in dB with proper normalization. It is found that the data are of high quality with a 60-dB drop in the co-polarized antenna patterns from the central peak value to its side-lobe regions at scan angles beyond 30 deg. The unpacked antenna pattern data produced in this study provide a useful database for data users to correct the antenna side-lobe contribution to MSU measurements. All of the data are available to the scientific community on a single CD-ROM.

  18. Design of a Microstrip Bowtie Antenna for Indoor Radio-Communications

    OpenAIRE

    Fraga-Rosales Hector; Reyes-Ayala Mario; Hernandez-Valdez Genaro; Andrade-Gonzalez Edgar Alejandro; Miranda-Tello Jose Raul; Cruz-Perez Felipe Alejandro; Castellanos-Lopez Sandra Lirio

    2017-01-01

    In this paper, a microstrip bowtie patch antenna (MBPA) for wireless indoor communications is carried out. Here, a microstrip transmission-line feed network was designed in order to match the MBPA. The proposed antenna uses a ground plane with the aim of narrowing down the back lobes in comparison with bowtie sheet antennas, which radiation pattern is omni-directional. The far-field pattern of the antenna was simulated using a finite-element numerical algorithm and obtained by interpolation e...

  19. Rethinking antenna requirements for medical implant systems

    NARCIS (Netherlands)

    Scanlon, W.G.

    2011-01-01

    This paper examines the basic medical implant communication service (MICS) link budgets for both uplink and downlink, with some recent advances in implant antenna technology and most importantly, the nature of the in body to out of body propagation path. The paper also discusses the emerging network

  20. Nimbus-7 SMMR Antenna Temperatures

    Data.gov (United States)

    National Aeronautics and Space Administration — The SMMR Antenna Temperatures (Nimbus-7) data set consists of antenna temperatures from passive microwave radiometers aboard NOAA's Nimbus-7 satellite. The...

  1. Annular Planar Monopole Antennas

    OpenAIRE

    Chen, Z. N.; Ammann, Max; Chia, W.Y. W.; See, T. S.P.

    2002-01-01

    A type of annular planar monopole antenna is presented. The impedance and radiation characteristics of the monopole with different holes and feed gaps are experimentally examined. The measured results demonstrate that the proposed antenna is capable of providing significantly broad impedance bandwidth with acceptable radiation performance.

  2. MEMS Tunable Antennas

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert Frølund

    2014-01-01

    Addressing low frequency bands is challenging on small platforms. Tunability is a promising solution to cover the bandwidth required for 4G mobile communication. The work presents two designs and shows that for comparable efficiency and bandwidth, the tunable antenna occupies half the volume...... required by the wide-band antenna....

  3. Printed Triband Terminal Antenna

    OpenAIRE

    John, Matthias; Ammann, Max; Farrell, R.

    2005-01-01

    This paper presents a printed triple-band multibranch monopole for use in modern wireless systems. The antenna is designed to operate in three bands which cover virtually all wireless channels. Parameters of the antenna geometry are varied and the effects of these variations on the impedance bandwidth are shown.

  4. Deployable Wide-Aperture Array Antennas

    Science.gov (United States)

    Fink, Patrick W.; Dobbins, Justin A.; Lin, Greg Y.; Chu, Andrew; Scully, Robert C.

    2005-01-01

    Inexpensive, lightweight array antennas on flexible substrates are under development to satisfy a need for large-aperture antennas that can be stored compactly during transport and deployed to full size in the field. Conceived for use aboard spacecraft, antennas of this type also have potential terrestrial uses . most likely, as means to extend the ranges of cellular telephones in rural settings. Several simple deployment mechanisms are envisioned. One example is shown in the figure, where the deployment mechanism, a springlike material contained in a sleeve around the perimeter of a flexible membrane, is based on a common automobile window shade. The array can be formed of antenna elements that are printed on small sections of semi-flexible laminates, or preferably, elements that are constructed of conducting fabric. Likewise, a distribution network connecting the elements can be created from conventional technologies such as lightweight, flexible coaxial cable and a surface mount power divider, or preferably, from elements formed from conductive fabrics. Conventional technologies may be stitched onto a supporting flexible membrane or contained within pockets that are stitched onto a flexible membrane. Components created from conductive fabrics may be attached by stitching conductive strips to a nonconductive membrane, embroidering conductive threads into a nonconductive membrane, or weaving predetermined patterns directly into the membrane. The deployable antenna may comprise multiple types of antenna elements. For example, thin profile antenna elements above a ground plane, both attached to the supporting flexible membrane, can be used to create a unidirectional boresight radiation pattern. Or, antenna elements without a ground plane, such as bow-tie dipoles, can be attached to the membrane to create a bidirectional array such as that shown in the figure. For either type of antenna element, the dual configuration, i.e., elements formed of slots in a conductive

  5. Handbook of antenna technologies

    CERN Document Server

    Liu, Duixian; Nakano, Hisamatsu; Qing, Xianming; Zwick, Thomas

    2016-01-01

    The Handbook of Antenna Technologies aims to present the rapid development of antenna technologies, particularly in the past two decades, and also showcasing the newly developed technologies and the latest applications. The handbook will provide readers with the comprehensive updated reference information covering theory, modeling and optimization methods, design and measurement, new electromagnetic materials, and applications of antennas. The handbook will widely cover not only all key antenna design issues but also fundamentals, issues related to antennas (transmission, propagation, feeding structure, materials, fabrication, measurement, system, and unique design challenges in specific applications). This handbook will benefit the readers as a full and quick technical reference with a high-level historic review of technology, detailed technical descriptions and the latest practical applications.

  6. A computer-controlled adaptive antenna system

    Science.gov (United States)

    Fetterolf, P. C.; Price, K. M.

    The problem of active pattern control in multibeam or phased array antenna systems is one that is well suited to technologies based upon microprocessor feedback control systems. Adaptive arrays can be realized by incorporating microprocessors as control elements in closed-loop feedback paths. As intelligent controllers, microprocessors can detect variations in arrays and implement suitable configuration changes. The subject of this paper is the application of the Howells-Applebaum power inversion algorithm in a C-band multibeam antenna system. A proof-of-concept, microprocessor controlled, adaptive beamforming network (BFN) was designed, assembled, and subsequent tests were performed demonstrating the algorithm's capacity for nulling narrowband jammers.

  7. Smart antennas in aerospace applications

    NARCIS (Netherlands)

    Verpoorte, Jaco; Schippers, Harmen; Roeloffzen, C.G.H.; Marpaung, D.A.I.

    2010-01-01

    The interest in Smart Antennas for aerospace applications is growing. This paper describes smart antennas which can be used on aircraft. Two aerospace applications are discussed in more detail: a phased array antenna with optical beam forming and a large vibrating phased array antenna with

  8. Optimisation of Microstrip Antenna

    Directory of Open Access Journals (Sweden)

    H. El Hamchary

    1996-04-01

    Full Text Available When choosing the most appropriate microstrip antenna configuration for particular applications, the kind of excitation of the radiating element is an essential factor that requires careful considerations. For controlling the distribution of energy of the linear or planar array of elements and for coupling energy to the individual elements, a wide variety of feed mechanisms are available. In this paper, the coaxial antenna feeding is assumed and the best (optimised feeding is found. Then, antenna characteristics such as radiation pattern, return loss, input impedance, and VSWR are obtained.

  9. Introduction to smart antennas

    CERN Document Server

    Balanis, Constantine A

    2007-01-01

    As the growing demand for mobile communications is constantly increasing, the need for better coverage, improved capacity, and higher transmission quality rises. Thus, a more efficient use of the radio spectrum is required. Smart antenna systems are capable of efficiently utilizing the radio spectrum and is a promise for an effective solution to the present wireless systems' problems while achieving reliable and robust high-speed high-data-rate transmission. The purpose of this book is to provide the reader a broad view of the system aspects of smart antennas. In fact, smart antenna systems co

  10. Getting Started with Netduino

    CERN Document Server

    Walker, Chris

    2012-01-01

    Start building electronics projects with Netduino, the popular open source hardware platform that's captured the imagination of makers and hobbyists worldwide. This easy-to-follow book provides the step-by-step guidance you need to experiment with Netduino and the .NET Micro Framework. Through a set of simple projects, you'll learn how to create electronic gadgets-including networked devices that communicate over TCP/IP. Along the way, hobbyists will pick up the basics of .NET programming, and programmers will discover how to work with electronics and microcontrollers. Follow the projects in

  11. Antennas from theory to practice

    CERN Document Server

    Huang, Yi

    2008-01-01

    Practical, concise and complete reference for the basics of modern antenna design Antennas: from Theory to Practice discusses the basics of modern antenna design and theory. Developed specifically for engineers and designers who work with radio communications, radar and RF engineering, this book offers practical and hands-on treatment of antenna theory and techniques, and provides its readers the skills to analyse, design and measure various antennas. Key features: Provides thorough coverage on the basics of transmission lines, radio waves and propag

  12. Dielectric Covered Planar Antennas

    Science.gov (United States)

    Llombart Juan, Nuria (Inventor); Lee, Choonsup (Inventor); Chattopadhyay, Goutam (Inventor); Gill, John J. (Inventor); Skalare, Anders J. (Inventor); Siegel, Peter H. (Inventor)

    2014-01-01

    An antenna element suitable for integrated arrays at terahertz frequencies is disclosed. The antenna element comprises an extended spherical (e.g. hemispherical) semiconductor lens, e.g. silicon, antenna fed by a leaky wave waveguide feed. The extended spherical lens comprises a substantially spherical lens adjacent a substantially planar lens extension. A couple of TE/TM leaky wave modes are excited in a resonant cavity formed between a ground plane and the substantially planar lens extension by a waveguide block coupled to the ground plane. Due to these modes, the primary feed radiates inside the lens with a directive pattern that illuminates a small sector of the lens. The antenna structure is compatible with known semiconductor fabrication technology and enables production of large format imaging arrays.

  13. Antenna pattern study

    Science.gov (United States)

    Harper, Warren

    1988-01-01

    Prediction of antenna radiation patterns has long been an important function in the design of command, communication, and tracking systems for rocket vehicles and spacecraft. An acceptable degree of assurance that a radio link will provide the required quality of data or certainty of correct command execution must be acquired by some means if the system is to be certified as reliable. Two methods have been used to perform this function: (1) Theoretical analysis, based on the known properties of basic antenna element types and their behavior in the presence of conductive structures of simple shape, and (2) Measurement of the patterns on scale models of the spacecraft or rocket vehicle on which the antenna is located. Both of these methods are ordinarily employed in the antenna design process.

  14. Shipboard Antenna Concepts: Structurally Independent 2- to 6-MHz Transmit Antenna Design.

    Science.gov (United States)

    1991-06-01

    degree of conductivity) of the ship composite structures are known, this antenna design can be modified to optimize its performance. Both scale ...modeling arid numerical mod- eling on computers are used extensively to design antennas. Present scale models and numerical models are adequate to develop...dielectric ct~ atlg MCLP1remcflts. A-7 IA-S CH 22 UF 04.477 3 i2.194 n~ 82.534 pF go 10.000 000 MHz C2?-528n Avg ;2.1n 10.310 - 3,- n START 1.000 000 MHz STOP

  15. Closing the Loop for ALMA - Three antennas working in unison open new bright year for revolutionary observatory

    Science.gov (United States)

    2010-01-01

    . The combination of the signals received at the individual antennas is crucial to achieve images of astronomical sources of unprecedented quality at its designed observing wavelengths. The three-antenna linkup is a critical step towards the observatory's operations as an interferometer. Although the first, successful measurements employing just two antennas were obtained at the ALMA high site from October 2009 (see ESO Announcement) and demonstrated the excellent performance of the instruments, the addition of the third antenna is a leap of vital importance into the future of the observatory. This major milestone for the project is known as "phase closure" and provides an important independent check on the quality of the interferometry. "The use of a network of three (or more) antennas in an interferometer dramatically enhances its performance over a simple pair of antennas," explains Wolfgang Wild, the European ALMA Project Manager. "This gives astronomers control over possible features which degrade the quality of the image, arising due to the instrument or to atmospheric turbulence. By comparing the signals received simultaneously by the three individual antennas, these unwanted effects can be cancelled out - this is completely impossible using only two antennas." To achieve this crucial goal, astronomers observed the light coming from a distant extragalactic source, the quasar QSO B1921-293, well known to astronomers for its bright emission at very long wavelengths, including the millimetre/submillimetre range probed by ALMA. The stability of the signal measured from this object shows that the antennas are working impressively well. Several additional antennas will be installed on the Chajnantor plateau over the next year and beyond, allowing astronomers to start producing early scientific results with the ALMA system around 2011. After this, the interferometer will steadily grow to reach its full scientific potential, with at least 66 antennas. ALMA, an

  16. ALMA Observatory Equipped with its First Antenna

    Science.gov (United States)

    2008-12-01

    antenna handover enables the observatory team to proceed with integrating the rest of the components, including the sensitive receivers that will collect the faint cosmic signals from space. "It marks the start of the next phase of the ALMA project. We have the front-end electronics and back-end electronics inside that antenna and now we can start the push to the high site, to get three antennas joined together interferometrically and start the process of science commissioning," said Russell. The antennas are tested at the Operations Support Facility, at an altitude of 9,500 feet, before being moved to the plateau of Chajnantor at 16,500 feet, a location where extreme dryness and altitude offer excellent conditions for observing the submillimeter-wavelength light for which the telescope is designed. ALMA's Operations Support Facility will also be the observatory’s control center. The wide plateau at Chajnantor also offers ample space for the construction of the antenna array, which is spread out and linked together over distances of more than 10 miles. “The ALMA antennas must withstand the harsh conditions at Chajnantor with strong winds, cold temperatures and a thin atmosphere with half as much oxygen as at sea level. This forbidding environment also poses challenges for the workers building ALMA,” said de Graauw. The antennas, which each weigh about 100 tons, can be moved to different positions in order to reconfigure the ALMA telescope. This will be carried out by two custom-designed transporters, each of which is some 33 feet wide, 66 feet long, and has 28 wheels. The ALMA Project is a partnership between the scientific communities of East Asia, Europe and North America with Chile. ALMA is funded in North America by the U.S. National Science Foundation in cooperation with the National Research Council of Canada and the National Science Council of Taiwan. ALMA construction and operations are led on behalf of North America by the National Radio Astronomy

  17. 5G antenna array with wide-angle beam steering and dual linear polarizations

    KAUST Repository

    Klionovski, Kirill

    2017-10-25

    In this paper, we present the design of a switched-beam antenna array at millimeter-wave frequencies for future 5G applications. The proposed antenna array is based on wideband patch antenna elements and a Butler matrix feed network. The patch antenna has a broad radiation pattern for wide-angle beam steering and allows the simultaneous operation with two orthogonal linear polarizations. A combination of two separated Butler matrices provides independent beam steering for both polarizations in the wide operating band. The antenna array has a simple multilayer construction, and it is made on a low-cost Rogers laminate.

  18. Directivity of Antenna Arrays

    Science.gov (United States)

    Bulgakova, A. A.; Gorobets, N. N.; Katrich, V. A.; Lyashchenko, V. A.

    2016-12-01

    Purpose: Theoretical investigation of directive gains of linear and planar antenna arrays depending on the distance between radiators and wavelength. Design/methodology/approach: Computing methods in applied mathematics in MathCad were used to calculate the twofold integrals of the radiation pattern over power throughout the whole space observed, defining the directivity in the most general terms. Patterns of radiators, i. e. elements of antenna arrays, are specified by mathematical models. The calculation accounts for the subintegral fast oscillating function. Findings: Calculations and analysis of a directive gain according to the number of radiators and distances between them in fractions of wavelength are made. It is shown that at the ratio of distance between radiators to wave-length being d/λ =0.5 the directivity of array of isotropic radiators is 1.5N², N - number of radiators. When increasing the d/λ to 0.65÷0.97 the directivity increases according to the law close to the linear one up to the maximum possible value for the specified number of radiators. With the increase of d/λ to the values greater than one, the directivity is significantly reduced (the “blinding” effect of non-phased antenna arrays) and its dependence with the growth of d/λ is decaying and oscillating in character. By that, the transfer function of antenna arrays has some vital difference from the transfer function of continuous antennas. Conclusions: Antenna arrays distort the waveform and spectrum of radiated and received signals as a result of irregular changes of their directivity depending on wavelength. The detected “blinding” effect of non-phased antenna arrays of large electrical dimensions must be taken into account in wideband and superwideband radio-electronics systems, especially in radio astronomy, telecommunications systems and superwideband radar.

  19. Antenna for Ultrawideband Channel Sounding

    DEFF Research Database (Denmark)

    Zhekov, Stanislav Stefanov; Tatomirescu, Alexandru; Pedersen, Gert F.

    2016-01-01

    A novel compact antenna for ultrawideband channel sounding is presented. The antenna is composed of a symmetrical biconical antenna modified by adding a cylinder and a ring to each cone. A feeding coaxial cable is employed during the simulations in order to evaluate and reduce its impact on the a......A novel compact antenna for ultrawideband channel sounding is presented. The antenna is composed of a symmetrical biconical antenna modified by adding a cylinder and a ring to each cone. A feeding coaxial cable is employed during the simulations in order to evaluate and reduce its impact...

  20. Explore the Capability of ESPAR Antennas for Low Cost Communication

    DEFF Research Database (Denmark)

    Han, Bo; Kalis, A; Papadias, C.

    . However, for higher modulation schemes like 16-QAM, more radiation patterns are needed which require a wider control range on the parasitic antenna load. In order to explore the capability of ESPAR antennas, negative resistance was proposed, but their values cannot be easily controlled both on the real...... and imaginary part. So a matching network is required to control the load value. This paper presents an idea of adjusting the parasitic ESPAR antenna loads with controllable passive elements. According to simulation, the control circuit consumes less than 1mW power on 64 patterns selection, which explores...

  1. The Starting Early Starting Smart Story.

    Science.gov (United States)

    Casey Family Programs, Seattle, WA.

    Starting Early Starting Smart (SESS) is an early childhood public/private initiative designed to identify new, empirical knowledge about the effectiveness of integrating substance abuse prevention, addictions treatment, and mental health services with primary health care and childcare service settings (e.g., Head Start, day care, preschool) to…

  2. AIS Algorithm for Smart Antenna Application in WLAN

    Directory of Open Access Journals (Sweden)

    Evizal Abdul Kadir

    2015-07-01

    Full Text Available Increasing numbers of wireless local area networks (WLAN replacing wired networks have an impact on wireless network systems, causing issues such as interference. The smart antenna system is a method to overcome interference issues in WLANs. This paper proposes an artificial immune system (AIS for a switch beam smart antenna system. A directional antenna is introduced to aim the beam at the desired user. The antenna consists of 8 directional antennas, each of which covers 45 degrees, thus creating an omnidirectional configuration of which the beams cover 360 degrees. To control the beam switching, an inexpensive PIC 16F877 microchip was used. An AIS algorithm was implemented in the microcontroller, which uses the received radio signal strength of the mobile device as reference. This is compared for each of the eight beams, after which the AIS algorithm selects the strongest signal received by the system and the microcontroller will then lock to the desired beam. In the experiment a frequency of 2.4 GHz (ISM band was used for transmitting and receiving. A test of the system was conducted in an outdoor environment. The results show that the switch beam smart antenna worked fine based on locating the mobile device.

  3. Geodetic antenna calibration test in the Antarctic environment

    Science.gov (United States)

    Grejner-Brzezinska, A.; Vazquez, E.; Hothem, L.

    2006-01-01

    TransAntarctic Mountain DEFormation (TAMDEF) Monitoring Network is the NSF-sponsored OSU and USGS project, aimed at measuring crustal motion in the Transantarctic Mountains of Victoria Land using GPS carrier phase measurements. Station monumentation, antenna mounts, antenna types, and data processing strategies were optimized to achieve mm-level estimates for the rates of motion. These data contributes also to regional Antarctic frame definition. Significant amount of data collected over several years allow the investigation of unique aspects of GPS geodesy in Antarctica, to determine how the error spectrum compares to the mid-latitude regions, and to identify the optimum measurement and data processing schemes for Antarctic conditions, in order to test the predicted rates of motion (mm-level w.r.t. time). The data collection for the TAMDEF project was initiated in 1996. The primary antenna used has been the Ashtech L1/L2 Dorne Margolin (D/M) choke ring. A few occupations involved the use of a Trimble D/M choke ring. The data were processed using the antenna calibration data available from the National Geodetic Survey (NGS). The recent developments in new antenna designs that are lighter in weight and lower in cost are being considered as a possible alternative to the bulkier and more expensive D/M choke ring design. In November 2003, in situ testing of three alternative models of L1/L2 antennas was conducted at a site located in the vicinity of McMurdo Station, Antarctica (S77.87, E166.56). The antenna models used in this test were: Ashtech D/M choke ring, Trimble D/M choke ring, Trimble Zephyr, and the NovAtel GPS-702. Two stations, spaced within 30 meters, were used in the test. Both had the characteristics similar to the stations of the TAMDEF network, i.e., the UNAVCO fixed-height, force-centered level mounts with a constant antenna offset were used, ensuring extreme stability of the antenna/ mount/pin set up. During each of the four 3-day test data collection

  4. Mode Matching for Optical Antennas.

    Science.gov (United States)

    Feichtner, Thorsten; Christiansen, Silke; Hecht, Bert

    2017-11-24

    The emission rate of a point dipole can be strongly increased in the presence of a well-designed optical antenna. Yet, optical antenna design is largely based on radio-frequency rules, ignoring, e.g., Ohmic losses and non-negligible field penetration in metals at optical frequencies. Here, we combine reciprocity and Poynting's theorem to derive a set of optical-frequency antenna design rules for benchmarking and optimizing the performance of optical antennas driven by single quantum emitters. Based on these findings a novel plasmonic cavity antenna design is presented exhibiting a considerably improved performance compared to a reference two-wire antenna. Our work will be useful for the design of high-performance optical antennas and nanoresonators for diverse applications ranging from quantum optics to antenna-enhanced single-emitter spectroscopy and sensing.

  5. Hemispheric ultra-wideband antenna.

    Energy Technology Data Exchange (ETDEWEB)

    Brocato, Robert Wesley

    2006-04-01

    This report begins with a review of reduced size ultra-wideband (UWB) antennas and the peculiar problems that arise when building a UWB antenna. It then gives a description of a new type of UWB antenna that resolves these problems. This antenna, dubbed the hemispheric conical antenna, is similar to a conventional conical antenna in that it uses the same inverted conical conductor over a ground plane, but it also uses a hemispheric dielectric fill in between the conductive cone and the ground plane. The dielectric material creates a fundamentally new antenna which is reduced in size and much more rugged than a standard UWB conical antenna. The creation of finite-difference time domain (FDTD) software tools in spherical coordinates, as described in SAND2004-6577, enabled this technological advance.

  6. Wireless Distributed Antenna MIMO

    DEFF Research Database (Denmark)

    2015-01-01

    The present disclosure relates to system applications of multicore optical fibers. One embodiment relates to a base transceiver station for a wireless telecommunication system comprising a plurality of antenna units arranged in a MIMO configuration and adapted for transmission and/or reception...... of radio-frequency signals, an optical transmitter in the form of an electro-optic conversion unit for each of said plurality of antenna units, each electro-optic conversion unit adapted for converting an RF signal into an optical signal, a plurality of a single core optical fibers for guiding the optical...

  7. Printed MIMO antenna engineering

    CERN Document Server

    Sharawi, Mohammad S

    2014-01-01

    Wireless communications has made a huge leap during the past two decades. The multiple-input-multiple-output (MIMO) technology was proposed in the 1990's as a viable solution that can overcome the data rate limit experienced by single-input-single-output (SISO) systems. This resource is focused on printed MIMO antenna system design. Printed antennas are widely used in mobile and handheld terminals due to their conformity with the device, low cost, good integration within the device elements and mechanical parts, as well as ease of fabrication.A perfect design companion for practicing engineers

  8. Antennas on circular cylinders

    DEFF Research Database (Denmark)

    Knudsen, H. L.

    1959-01-01

    antenna in a circular cylinder. By a procedure similar to the one used by Silver and Saunders, expressions have been derived for the field radiated from an arbitrary surface current distribution on a cylinder surface coaxial with a perfectly conducting cylinder. The cases where the space between the two...... cylindrical surfaces have the sane characteristic constants and different constants are treated separately. Extensive numerical computations of the field radiated from the slot antennas described here are being carried out, but no numerical results are yet available...

  9. Antenna (Selected Articles),

    Science.gov (United States)

    1981-11-04

    random layout of the antenna (i.e. ’I=O). It is apparent from the figure that in the region of optimal N, the quantities AN and a2 change slowly. With a...introducing phase distribution of the field along the antenna equal to Z2W we can, in the limits of small angles in the region 0o O0 at distance R0 (focal...Shifrin, Ya. S. "Question of the Effect of Fluctuations on the Diffraction Image of a Focusing System," Trudy ARTA No. 46, 1960. 4. Tatarskiy, V. I. Teoria

  10. Non-standard antennas

    CERN Document Server

    Le Chevalier, Francois; Staraj, Robert

    2013-01-01

    This book aims at describing the wide variety of new technologies and concepts of non-standard antenna systems - reconfigurable, integrated, terahertz, deformable, ultra-wideband, using metamaterials, or MEMS,  etc, and how they open the way to a wide range of applications, from personal security and communications to multifunction radars and towed sonars, or satellite navigation systems, with space-time diversity on transmit and receive. A reference book for designers  in this lively scientific community linking antenna experts and signal processing engineers.

  11. A modified Wheeler cap method for radiation efficiency measurement of balanced electrically small antennas

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Pivnenko, Sergey; Breinbjerg, Olav

    2010-01-01

    Measurement of radiation efficiency for ultra small antennas represents a great challenge due to influence of the feeding cable. The Wheeler cap method is often used to measure the radiation efficiency of small antennas. However, it is well applicable for antennas on a ground plane......, but not for balanced antennas like loops or dipoles. In this paper, a modified Wheeler cap method is proposed for the radiation efficiency measurement of balanced electrically small antennas and a three-port network model of the Wheeler cap measurement is introduced. The advantage of the modified method...... is that it is wideband, thus does not require any balun, and both the antenna input impedance and radiation efficiency can be obtained. An electrically small loop antenna and a wideband dipole were simulated and measured according to the proposed method and the results of measurements and simulations are presented...

  12. Wireless communication with multiple antennas

    Indian Academy of Sciences (India)

    admin

    Wireless communications has seen a very rapid growth, both in practice and theory, during the past one decade. Most of the present wireless communication systems use one transmit antenna and one receive antenna. However, communication with multiple transmit and multiple receive antennas can enormously increase ...

  13. Validation of Emulated Omnidirectional Antenna Output Using Directive Antenna Data

    DEFF Research Database (Denmark)

    Hejselbæk, Johannes; Karstensen, Anders; Nielsen, Jesper Ødum

    2017-01-01

    In this paper, we present validation of a method for constructing a virtual omnidirectional antenna in the azimuth plane. The virtual omnidirectional antenna utilizes a combination of data from directive horn antennas. The aim is to utilize the high gain of the horn antenna to improve the dynamic...... range of channel sounding measurements conducted in the centimeter and millimeter wave bands. The resulting complex impulse response from the virtual omnidirectional antenna is used to find the power-delay-profile (PDP). This is then compared to measurements conducted at the same time using a real...... omnidirectional antenna. The validation shows that the synthesized omnidirectional is capable of predicting main components and the slope of the PDP. Further, it is shown that by choosing angular sampling steps corresponding to the half power beam width (HPBW) of the used antenna similar power levels can...

  14. Antenna feeds and receivers

    Science.gov (United States)

    Mccall, B.

    1972-01-01

    The results of 7 months of study, tradeoffs, test design, and fabrication are presented for an effort to modify three ground stations in support of the ATS-F program. As a result of tests on the existing feed system of the Rosman No. 2 85-foot antenna and on the transportable ground station (TGS) 40-foot antenna, it was determined that modifications of the existing phase-compensating rotary joints at Rosman are feasible. Other components must be completely replaced. In the TGS antenna feed system, it was found to be feasible to broadband the existing monopulse comparator by adding simple irises and posts; both spare and active comparators were modified. The TGS polarizers can be broadbanded by adjusting existing pins and adding two new pins. These modifications are also directly applicable to the Mojave 40-foot antenna. Detailed electrical and mechanical characteristics are presented for the new equipment, as well as installation plans to enable NASA and its contractors to determine the adequacy of the designs and to confirm that planned locations are both available and compatible with planned operational concepts.

  15. Frequency scanning microstrip antennas

    DEFF Research Database (Denmark)

    Danielsen, Magnus; Jørgensen, Rolf

    1979-01-01

    The principles of using radiating microstrip resonators as elements in a frequency scanning antenna array are described. The resonators are cascade-coupled. This gives a scan of the main lobe due to the phase-shift in the resonator in addition to that created by the transmission line phase...

  16. Biconical receiving antenna

    Science.gov (United States)

    Grimes, Dale M.

    1982-05-01

    The modal solution to a biconical receiving antenna with arbitrary arm angles and lengths is presented in the form of sums over special functions; sums which are exact in the sense that no electromagnetic approximations are made. The antenna load is confined within a sphere of small radius centered at the apices of the cones. The analytical formulation is presented, along with solutions for ψ very small and very large, and certain selected numerical data. The general solution permits calculation of all detailed fields near and far, both receiving and transmitting current modes on the antenna arms and caps and the power and the momentum absorbed by the antenna from an incoming plane wave. It is shown that the receiving current modes are necessary for electromagnetic momentum to be conserved during power reception. Detailed calculation of comparative receiving and transmitting admittances confirms that they are identical, as predicted by the reciprocity theorem. The radiation patterns, however, for retransmission during reception and for transmission differ.

  17. Antenna theory analysis and design

    CERN Document Server

    Balanis, Constantine A

    2005-01-01

    The discipline of antenna theory has experienced vast technological changes. In response, Constantine Balanis has updated his classic text, Antenna Theory, offering the most recent look at all the necessary topics. New material includes smart antennas and fractal antennas, along with the latest applications in wireless communications. Multimedia material on an accompanying CD presents PowerPoint viewgraphs of lecture notes, interactive review questions, Java animations and applets, and MATLAB features. Like the previous editions, Antenna Theory, Third Edition meets the needs of e

  18. Quartz antenna with hollow conductor

    Science.gov (United States)

    Leung, Ka-Ngo; Benabou, Elie

    2002-01-01

    A radio frequency (RF) antenna for plasma ion sources is formed of a hollow metal conductor tube disposed within a glass tube. The hollow metal tubular conductor has an internal flow channel so that there will be no coolant leakage if the outer glass tube of the antenna breaks. A portion of the RF antenna is formed into a coil; the antenna is used for inductively coupling RF power to a plasma in an ion source chamber. The antenna is made by first inserting the metal tube inside the glass tube, and then forming the glass/metal composite tube into the desired coil shape.

  19. Electromagnetic reciprocity in antenna theory

    CERN Document Server

    Stumpf, Martin

    2018-01-01

    The reciprocity theorem is among the most intriguing concepts in wave field theory and has become an integral part of almost all standard textbooks on electromagnetic (EM) theory. This book makes use of the theorem to quantitatively describe EM interactions concerning general multiport antenna systems. It covers a general reciprocity-based description of antenna systems, their EM scattering properties, and further related aspects. Beginning with an introduction to the subject, Electromagnetic Reciprocity in Antenna Theory provides readers first with the basic prerequisites before offering coverage of the equivalent multiport circuit antenna representations, EM coupling between multiport antenna systems and their EM interactions with scatterers, accompanied with the corresponding EM compensation theorems.

  20. Self-Resonant Electrically Small Loop Antennas for Hearing-Aids Application

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Breinbjerg, Olav

    2010-01-01

    using any additional matching network and lumped components. The dimension of the proposed antenna is 0.10λ0×0.03λ0, and it is designed to be resonant at 900 MHz. Both the analytical model and numerical simulations are discussed and explained. The antenna is also fabricated and measured in an anechoic...... chamber. The measurement methods for electrically small antennas are reported....

  1. Use of microstrip patch antennas in grain and pulverized materials permittivity measurement

    Science.gov (United States)

    El Sabbagh, M.A.; Ramahi, O.M.; Trabelsi, S.; Nelson, S.O.; Khan, L.

    2003-01-01

    A free-space microwave system developed for the measurement of the relative complex permittivity of granular materials and of pulverized materials was reported. The system consists of a transmitting antenna and a receiving antenna separated by a space filled by the sample to be characterized and a network analyzer for transmission measurement. The receiving antenna was mounted on a movable plate, which gives the flexibility of having different sample thicknesses.

  2. A Compact Annular Ring Microstrip Antenna for WSN Applications

    Directory of Open Access Journals (Sweden)

    Daihua Wang

    2012-06-01

    Full Text Available A compact annular ring microstrip antenna was proposed for a wireless sensor network (WSN application in the 2.4 GHz band. In this paper the major considerations of the conformal antenna design were the compact size and the impact on antenna’s performance of a steel installation base. By using a chip resistor of large resistance (120 Ω the antenna size was reduced to 38% of that a conventional annular ring patch antenna. With the addition of the steel installation base the resonant frequency of the antenna increases about 4.2% and the bandwidth reduces from 17.5% to 11.7% by adjusting the load resistance simultaneously. Several key parameters were discussed and optimized, and the antenna was fabricated and its performance measured. The antenna is well matched at 2.4 GHz with 34.2 dB return loss and –2.5 dBi peak gain. Meanwhile, it exhibits excellent radiation patterns with very low cross-polarization levels.

  3. Circular Microstrip Antenna with Fractal Slots for Multiband Applications

    Science.gov (United States)

    Singh, Sivia Jagtar; Singh, Gurpreet; Bharti, Gurpreet

    2017-10-01

    In this paper, a multiband, fractal, slotted, Circular Microstrip Patch Antenna for GSM, WiMAX, C and X bands (satellite communication applications) is presented. A cantor set theory is used to make fractal slots for obtaining the desired multiband. The projected antenna is simulated using Ansys HFSS v13.0 software. Simulation test of this antenna has been carried out for a frequency range of 1 GHz-10 GHz and a peak gain of 9.19 dB at a resonance frequency of 1.9 GHz is obtained. The antenna also resonates at 3.7 GHz, 6.06 GHz and 7.9 GHz with gains of 3.04 dB, 5.19 dB and 5.39 dB respectively. Parameters like voltage standing wave ratio, return loss, and gain are used to compare the results of the projected antenna with conventional CMPA's of same dimensions with full and defective grounds. The projected antenna is fabricated on a glass epoxy material and is tested using Vector Network Analyzer. The performance parameters of the antenna are found to in good agreement with each both using simulated and measured data.

  4. Co-simulation of a complete rectenna with a circular slot loop antenna in CPW technology

    Science.gov (United States)

    Rivière, Jérôme; Douyère, Alexandre; Cazour, Jonathan; Alicalapa, Frédéric; Luk, Jean-Daniel Lan Sun

    2017-05-01

    This study starts with the design of a planar and compact CPW antenna fabricated on Arlon AD1000 substrate, ɛr=10.35. The antenna is a coplanar waveguide (CPW) fed circular slot loop antenna matched to the standard impedance 50 Ω by two stubs. The goal is to implement this antenna with a CPW RF/DC rectifier to build an optimized low power level rectenna. The rectenna design is restricted to allow easy and fast fabrication of an array with a high reproducibility. The full rectenna is simulated and achieves 10% effciency at -20 dBm.

  5. Radiofrequency magnetic resonance coils and communication antennas: Simulation and design strategies.

    Science.gov (United States)

    Giovannetti, Giulio; Tiberi, Gianluigi

    2017-12-01

    Coils simulation and design is a fundamental task to maximize Signal-to-Noise Ratio in Magnetic Resonance applications. In the meantime, in the last years the issue of accurate communication antennas analysis has grown. Coil design techniques take advantage of computer simulations in dependence on the magnetic field wavelength and coil sizes. In particular, since at high frequencies coils start to behave as antennas, modern Magnetic Resonance coil development exploits numerical methods typically employed for antennas simulation. This paper reviews coil and antenna performance parameters and focuses on the different simulation approaches in dependence on the near/far field zones and operating frequency. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Large-Aperture Membrane Active Phased-Array Antennas

    Science.gov (United States)

    Karasik, Boris; McGrath, William; Leduc, Henry

    2009-01-01

    Large-aperture phased-array microwave antennas supported by membranes are being developed for use in spaceborne interferometric synthetic aperture radar systems. There may also be terrestrial uses for such antennas supported on stationary membranes, large balloons, and blimps. These antennas are expected to have areal mass densities of about 2 kg/sq m, satisfying a need for lightweight alternatives to conventional rigid phased-array antennas, which have typical areal mass densities between 8 and 15 kg/sq m. The differences in areal mass densities translate to substantial differences in total mass in contemplated applications involving aperture areas as large as 400 sq m. A membrane phased-array antenna includes patch antenna elements in a repeating pattern. All previously reported membrane antennas were passive antennas; this is the first active membrane antenna that includes transmitting/receiving (T/R) electronic circuits as integral parts. Other integral parts of the antenna include a network of radio-frequency (RF) feed lines (more specifically, a corporate feed network) and of bias and control lines, all in the form of flexible copper strip conductors on flexible polymeric membranes. Each unit cell of a prototype antenna (see Figure 1) contains a patch antenna element and a compact T/R module that is compatible with flexible membrane circuitry. There are two membrane layers separated by a 12.7-mm air gap. Each membrane layer is made from a commercially available flexible circuit material that, as supplied, comprises a 127-micron-thick polyimide dielectric layer clad on both sides with 17.5-micron-thick copper layers. The copper layers are patterned into RF, bias, and control conductors. The T/R module is located on the back side of the ground plane and is RF-coupled to the patch element via a slot. The T/R module is a hybrid multilayer module assembled and packaged independently and attached to the membrane array. At the time of reporting the information for

  7. Smart adaptive array antennas for wireless communcations

    Science.gov (United States)

    Christodoulou, Christos G.; Georgiopoulos, Michael

    2001-08-01

    This paper discusses an experimental neural network based smart antenna capable of performing direction finding and the necessary beamforming. The Radial Basis Function Neural Network (RBFNN) algorithm is used for both tasks and for multiple signals. The algorithm operates in two stages. The field of view of the antenna array is divided into spatial sectors, then each network is trained in the first stage to detect signals emanating from sources in that sector. According to the outputs of the first stage, one or more networks of the second stage can be activated so as to estimate the exact location of the sources. No a priori knowledge is required about the number of sources, and the networks can be designed to arbitrary angular resolution. Some experimental results are shown and compared with other algorithms, such as, the Fourier Transform and the MUSIC algorithm. The comparisons show the superior performance of the RBFNN and its ability to overcome many limitations of the conventional and other superresolution techniques, specifically by reducing the computational complexity and the ability to deal with a large number of sources.

  8. Planar C-Band Antenna with Electronically Controllable Switched Beams

    Directory of Open Access Journals (Sweden)

    Mariano Barba

    2009-01-01

    Full Text Available The design, manufacturing, and measurements of a switchable-beam antenna at 3.5 GHz for WLL or Wimax base station antennas in planar technology are presented. This antenna performs a discrete beam scan of a 60∘ sector in azimuth and can be easily upgraded to 5 or more steps. The switching capabilities have been implemented by the inclusion of phase shifters based on PIN diodes in the feed network following a strategy that allows the reduction of the number of switches compared to a classic design. The measurements show that the design objectives have been achieved and encourage the application of the acquired experience in antennas for space applications, such as X-band SAR and Ku-band DBS.

  9. Miniaturized Balanced Antenna with Integrated Balun for Practical LTE Applications

    Directory of Open Access Journals (Sweden)

    I. T. E. Elfergani

    2017-06-01

    Full Text Available A design of dual-band balanced antenna structure operating in the 700 and 2600MHz LTE bands is studied and investigated. The overall dimensions of the radiator are 50 × 18 × 7 mm^3 allowing it to be easily concealed within mobile handsets. A broad-band balun is designed and integrated with the antenna handset in order to provide the feeding network and perform the measurements of the antenna radiation performance. Prototypes of proposed antenna with and without balun are fabricated and verified. The simulated and practical results with and without the handheld effects in terms of reflection coefficient, power gain and radiation pattern, are studied and shown reasonable agreement.

  10. DSN Antenna Array Architectures Based on Future NASA Mission Needs

    Science.gov (United States)

    MacNeal, Bruce E.; Abraham, Douglas S.; Cesarone, Robert J.

    2007-01-01

    A flexible method of parametric, full life-cycle cost analysis has been combined with data on NASA's future communication needs to estimate the required number and operational dates of new antennas for the Deep Space Network (DSN). The requirements were derived from a subset of missions in the Integrated Mission Set database of NASA's Space Communications Architecture Working Group. Assuming that no new antennas are 'constructed', the simulation shows that the DSN is unlikely to meet more than 20% of mission requirements by 2030. Minimum full life-cycle costs result when antennas in the diameter range, 18m-34m, are constructed. Architectures using a mixture of antenna diameters produce a slightly lower full life-cycle cost.

  11. Relative vs Absolute Antenna Calibrations: How, when, and why do they differ? A Comparison of Antenna Calibration Catalogs

    Science.gov (United States)

    Mader, G. L.; Bilich, A. L.

    2013-12-01

    Since 1994, NGS has computed relative antenna calibrations for more than 350 antenna models used by NGS customers and geodetic networks worldwide. In a 'relative' calibration, the antenna under test is calibrated relative to a standard reference antenna, the AOA D/M_T chokering. The majority of NGS calibrations have been made publicly available at the web site www.ngs.noaa.gov/ANTCAL as well as via the NGS master calibrations file ant_info.003. In the mid-2000's, institutions in Germany began distributing 'absolute' antenna calibrations, where the antenna under test is calibrated independent of any reference antenna. These calibration methods also overcame some limitations of relative calibrations by going to lower elevation angles and capturing azimuthal variations. Soon thereafter (2008), the International GNSS Service (IGS) initiated a geodetic community movement away from relative calibrations and toward absolute calibrations as the defacto standard. The IGS now distributes a catalog of absolute calibrations taken from several institutions, distributed as the IGS master calibrations file igs08.atx. The competing methods and files have raised many questions about when it is or is not valid to process a geodetic network using a combination of relative and absolute calibrations, and if/when it is valid to combine the NGS and IGS catalogs. Therefore, in this study, we compare the NGS catalog of relative calibrations against the IGS catalog of absolute calibrations. As of the writing of this abstract, there are 77 antenna+radome combinations which are common to both the NGS relative and IGS absolute catalogs, spanning 16 years of testing (1997 to present). 50 different antenna models and 8 manufacturers are represented in the study sample. We apply the widely-accepted standard method for converting relative to absolute, then difference the calibrations. Various statistics describe the observed differences between phase center offset (PCO), phase center variation

  12. Two-Way Multi-Antenna Relaying with Simultaneous Wireless Information and Power Transfer

    Directory of Open Access Journals (Sweden)

    Thanaphat Srivantana

    2017-03-01

    Full Text Available In this paper, we propose various kinds of two-way multi-antenna relaying with simultaneous wireless information and power transfer (SWIPT and investigate their performance. Specifically, we first consider a two-way relay network where two single-antenna end nodes communicate with each other through a multi-antenna relay node that is energy constrained. This relay node harvests energy from the two end nodes and use the harvested energy for forwarding their information. Six relaying schemes that support the considered network then build on the power splitting-based relaying and time switching-based relaying protocols. The average bit error rates of these schemes are evaluated and compared by computer simulations considering several network parameters, including the number of relay antennas, power splitting ratio, and energy harvesting time. Such evaluation and comparison provide useful insights into the performance of SWIPT-based two-way multi-antenna relaying.

  13. Enhanced Antenna Performances Using Planar Circularly Symmetric EBG's

    NARCIS (Netherlands)

    Maagt, P. de; Llombart, N.; Neto, A.; Gerini, G.

    2005-01-01

    Planar circularly symmetric (PCS) electromagnetic band-gap (EBG) substrates have recently been proposed to suppress surface waves (Llombart, N. et al., 2004). The application of PCS-EBG to reduce the surface waves excited by an antenna printed on a dielectric slab is discussed. The study starts from

  14. Start-up story: IP and access challenges: introducing RedLink Network – a new community-based registry to create efficiencies for libraries

    Directory of Open Access Journals (Sweden)

    Kent Anderson

    2017-03-01

    Full Text Available A major pain point for librarians and publishers is the work involved in keeping authentication credentials (IP addresses, Shibboleth and link resolvers current and ensuring their accuracy. Yet, the infrastructure of the internet has solved similar problems like this before. RedLink Network is a free, community-driven platform, run by a public benefit company. It allows librarians to broadcast their access credentials and branding, track uptake across their publishers and platforms, and solve access issues collaboratively. It also enables mapping of hierarchies (consortia and subsidiaries. This article describes what inspired the creation of RedLink Network, how it benefits librarians and publishers and, ultimately, how it can help ensure access for students, researchers and knowledge workers.

  15. Microstrip Antennas with Polarization Diversity across a Wide Frequency Range and Phased Array Antennas for Radar and Satellite Communications

    Science.gov (United States)

    Ho, Kevin Ming-Jiang

    The thesis comprises of 3 projects; an L-band microstrip antenna with frequency agility and polarization diversity, X-band phased array antennas incorporating commercially packaged RFIC phased array chips, and studies for Ku/Ka-band shared aperture antenna array. The first project features the use of commercially packaged RF-MEMS SPDT switches, that boasts of high reliability, high linearity, low losses, hermetically packaged and fully compatible for SMTA processes for mass-assembly and production. Using the switches in a novel manner for the feed network, microstrip antennas with polarization diversity are presented. Frequency agility is achieved with the use of tuning diodes to provide capacitive loading to the antenna element. Additional inductance effects from surface-mounted capacitors, and its impact, is introduced. Theoretical cross-polarization of probe-fed antenna elements is presented for both linear and circular polarized microstrip antennas. Designs and measurements are presented, for microstrip antennas with polarization diversity, wide frequency tuning range, and both features. Replacement of the tuning diodes with commercially-packaged high Q RF MEMS tunable capacitors will allow for significant improvements to the radiation efficiency. In another project, multi-channel CMOS RFIC phased-array receiver chips are assembled in QFN packages and directly integrated on the same multi-layered PCB stack-up with the antenna arrays. Problems of isolation from the PCB-QFN interface, and potential performance degradation on antenna array from the use of commercial-grade laminates for assembly requirements, namely potential scan blindness and radiation efficiency, are presented. Causes for apparent drift of dielectric constant for microstrip circuits, and high conductor losses observed in measurements, are introduced. Finally, studies are performed for the design of a Ku/Ka-Band shared aperture array. Different approaches for developing dual-band shared apertures

  16. Collinear Microstrip Patch Antenna

    Directory of Open Access Journals (Sweden)

    M. Mazanek

    2005-12-01

    Full Text Available The paper presents a brief overview of the development of so calledcollinear types of antenna arrays. A new type of this structure inmicrostrip technology is further introduced. The principle of theantenna operation is explained via surface current distribution ofexcited modes. Such distribution is reached via geometricalperturbation of a radiating element by slots introduced in such a waythat they e liminate radiation from even half current wavelengths . Theinitial design and optimization of the prototype operating in RFID band(869 MHz has been performed in planar simulator Zeland IE3D. Aprototype has been realized and measured. The reached results show thatthe presented antenna has directional character as it can be expecteddue to the proposed technology and the presence of a planar groundplane.

  17. The Gain Estimation of a Fabry-Perot Cavity (FPC Antenna with a Finite Dimension

    Directory of Open Access Journals (Sweden)

    Taek-Sun Kwon

    2017-10-01

    Full Text Available In this paper, we have presented an equation for estimating the gain of a Fabry-Perot cavity (FPC antenna with a finite dimension. When an FPC antenna has an infinite dimension and its height is half of a wavelength, the maximum gain of that FPC antenna can be obtained theoretically. If the FPC antenna does not have a dimension sufficient for multiple reflections between a partially reflective surface (PRS and the ground, its gain must be less than that of an FPC antenna that has an infinite dimension. In addition, the gain of an FPC antenna increases as the dimension of a PRS increases and becomes saturated from a specific dimension. The specific dimension where the gain starts to saturate also gets larger as the reflection magnitude of the PRS becomes closer to one. Thus, it would be convenient to have a gain equation when considering the dimension of an FPC antenna in order to estimate the exact gain of the FPC antenna with a specific dimension. A gain versus the dimension of the FPC antenna for various reflection magnitudes of PRS has been simulated, and the modified gain equation is produced through the curve fitting of the full-wave simulation results. The resulting empirical gain equation of an FPC antenna whose PRS dimension is larger than 1.5λ0 has been obtained.

  18. Towards an ultra-low-power electronically controllable array antenna for WSN

    CSIR Research Space (South Africa)

    Lysko, AA

    2012-09-01

    Full Text Available This paper discusses steps towards a low-power beam-switching array antenna suitable for wireless sensor network (WSN) applications. Such an antenna will help to improve the signal to noise ratio (SNR), and thus throughput, latency and other...

  19. Numerical analysis of patch antenna as antenna array element

    OpenAIRE

    Kizimenko, V.; Bobkov, Y

    2009-01-01

    The patch antennas as antenna array element can be modeling by finite element method (programs Microwave Office, Ansoft HFSS and other). But this method need to use fast computer with memory large size. In this work the authors make an attempt to use thin wire integral equation method for patch antenna analysis. The results of modeling by proposed method are compared with the same of modeling by finite elements method and experimental results.

  20. Low Profile Antenna Performance Study Part 2. Broadband Antenna Techniques Survey

    Science.gov (United States)

    1977-10-01

    shaped radiators, presented in the literature [141, [15], and depicted in Figs. 3b and c, resemble the biconical antenna and Alford’s tapered-horn...V Research and Development Technical Report .ECOM-4542 LOW PROFILE ANTENNA PERFORMANCE STUDY PART I1: BROADBAND ANTENNA TECHNIQUES SURVEY C. M...Small antenna , low-profile antenna , broadband matching, folded antennas , multi- element antennas , antenna loading. 90. ABSTRACT (Conlinu en revere, side

  1. Paper-based inkjet-printed ultra-wideband fractal antennas

    KAUST Repository

    Maza, Armando Rodriguez

    2012-01-01

    For the first time, paper-based inkjet-printed ultra-wideband (UWB) fractal antennas are presented. Two new designs, a miniaturised UWB monopole, which utilises a fractal matching network and is the smallest reported inkjet-printed UWB printed antenna to date, and a fourth-order Koch Snowflake monopole, which utilises a Sierpinski gasket fractal for ink reduction, are demonstrated. It is shown that fractals prove to be a successful method of reducing fabrication costs in inkjet-printed antennas, while retaining or enhancing printed antenna performance. © 2012 The Institution of Engineering and Technology.

  2. Highly sensitive antenna using inkjet overprinting with particle-free conductive inks.

    Science.gov (United States)

    Komoda, Natsuki; Nogi, Masaya; Suganuma, Katsuaki; Otsuka, Kanji

    2012-11-01

    Printed antennas with low signal losses and fast response in high-frequency bands have been required. Here we reported on highly sensitive antennas using additive patterning of particle-free metallo-organic decomposition silver inks. Inkjet overprinting of metallo-organic decomposition inks onto copper foil and silver nanowire line produced antenna with mirror surfaces. As a result, the overprinted antennas decreased their return losses at 0.5-4.0 GHz and increased the speed of data communication in WiFi network.

  3. Reconstruction of neutron spectra using neural networks starting from the Bonner spheres spectrometric system; Reconstruccion de espectros de neutrones usando redes neuronales a partir del sistema espectrometrico de esferas de Bonner

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz R, J.M.; Martinez B, M.R.; Arteaga A, T.; Vega C, H.R.; Hernandez D, V.M.; Manzanares A, E. [Universidad Autonoma de Zacatecas, A.P. 336, 98000 Zacatecas (Mexico)

    2005-07-01

    The artificial neural networks (RN) have been used successfully to solve a wide variety of problems. However to determine an appropriate set of values of the structural parameters and of learning of these, it continues being even a difficult task. Contrary to previous works, here a set of neural networks is designed to reconstruct neutron spectra starting from the counting rates coming from the detectors of the Bonner spheres system, using a systematic and experimental strategy for the robust design of multilayer neural networks of the feed forward type of inverse propagation. The robust design is formulated as a design problem of Taguchi parameters. It was selected a set of 53 neutron spectra, compiled by the International Atomic Energy Agency, the counting rates were calculated that would take place in a Bonner spheres system, the set was arranged according to the wave form of those spectra. With these data and applying the Taguchi methodology to determine the best parameters of the network topology, it was trained and it proved the same one with the spectra. (Author)

  4. Stretchable antenna for wearable electronics

    KAUST Repository

    Hussain, Muhammad Mustafa

    2017-04-13

    Various examples are provided for stretchable antennas that can be used for applications such as wearable electronics. In one example, a stretchable antenna includes a flexible support structure including a lateral spring section having a proximal end and at a distal end; a metallic antenna disposed on at least a portion of the lateral spring section, the metallic antenna extending along the lateral spring section from the proximal end; and a metallic feed coupled to the metallic antenna at the proximal end of the lateral spring section. In another example, a method includes patterning a polymer layer disposed on a substrate to define a lateral spring section; disposing a metal layer on at least a portion of the lateral spring section, the metal layer forming an antenna extending along the portion of the lateral spring section; and releasing the polymer layer and the metal layer from the substrate.

  5. Miniaturization of Spherical Magnetodielectric Antennas

    DEFF Research Database (Denmark)

    Hansen, Troels Vejle

    The fundamental limitations in performance of electrically small antennas (ESAs) - and how far these may be approached - have been of great interest for over a century. Particularly over the past few decades, it has become increasingly relevant and important, to approach these limits in view...... to the important antenna parameters of radiation efficiency e and impedance bandwidth. For single-mode antennas the fundamental minimum Q is the Chu lower bound. In this Ph.D. dissertation, the topic is miniaturization of spherical antennas loaded by an internal magnetodielectric core. The goal is to determine......, quantify, and assess the effects of an internal material loading upon antenna performance, including its potentials towards miniaturization. Emphasis have been upon performing an exhaustive and exact analysis of rigorous validity covering a large class of spherical antennas. In the context of this study...

  6. A Compact UWB Diversity Antenna

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2014-01-01

    Full Text Available A compact printed ultrawideband (UWB diversity antenna with a size of 30 mm × 36 mm operating at a frequency range of 3.1–10.6 GHz is proposed. The antenna is composed of two semielliptical monopoles fed by two microstrip lines. Two semicircular slots, two rectangular slots, and one stub are introduced in the ground plane to adjust the impedance bandwidth of the antenna and improve the isolation between two feeding ports. The simulated and measured results show that impedance bandwidth of the proposed antenna can cover the whole UWB band with a good isolation of < −15 dB. The radiation patterns, peak antenna gain, and envelope correlation coefficient are also measured and discussed. The measured results show that the proposed antenna can be a good candidate for some portable MIMO/diversity UWB applications.

  7. Near Field Antenna Measurement System.

    Science.gov (United States)

    1978-01-11

    provided which , while designed pr imar ily to support the AN/ TPQ-36 and AN/TPQ-37 antenna s, can readily be used with other antennas. This antenna...tJ~~ ct .nt.r. d In Block 20, Ii dill spans from Raport) Same 13. S U P P L E M E N T A R Y N OT E S None 19. KEY WORDS (Conti nua on revere, side if

  8. Antenna arrays a computational approach

    CERN Document Server

    Haupt, Randy L

    2010-01-01

    This book covers a wide range of antenna array topics that are becoming increasingly important in wireless applications, particularly in design and computer modeling. Signal processing and numerical modeling algorithms are explored, and MATLAB computer codes are provided for many of the design examples. Pictures of antenna arrays and components provided by industry and government sources are presented with explanations of how they work. Antenna Arrays is a valuable reference for practicing engineers and scientists in wireless communications, radar, and remote sensing, and an excellent textbook for advanced antenna courses.

  9. Bandwidth Enhancement of Antenna Arrays Utilizing Mutual Coupling between Antenna Elements

    Directory of Open Access Journals (Sweden)

    Min Wang

    2010-01-01

    Full Text Available The mutual coupling effect between antenna elements on an array's bandwidth is investigated using scattering parameters instead of the mutual impedance. First, an approximate expression is derived for matched voltage standing wave ratio (VSWR bandwidth of a tuned antenna, which reveals that the bandwidth is inversely proportional to the magnitude |Γ0'(ω0| of the frequency derivative of the reflection coefficient. Next, considering linear antenna arrays with corporate feed as an example, closed-form expressions of the reflection coefficient are derived at the input port of the feeding network, which shows that the active reflection coefficient of an array is the linear superposition of elements' passive reflection coefficient S11 and the mutual coupling coefficient S12 from adjacent elements. The VSWR bandwidth expressions for an array imply that bandwidth enhancement of the overall array can be achieved when the element passive reflection coefficient S11 and mutual coupling S12 are cancelled, as well as the frequency derivatives S11' and S12' also cancel each other. Slot arrays and a two-element Vivaldi array are investigated to verify the validity of our theoretical analysis. Numerical and experimental results are presented to successfully demonstrate the bandwidth enhancement of antenna arrays utilizing mutual coupling effect.

  10. Development and coupling analysis of active skin antenna

    Science.gov (United States)

    Zhou, Jinzhu; Huang, Jin; He, Qingqang; Tang, Baofu; Song, Liwei

    2017-02-01

    An active skin antenna is a multifunctional composite structure that can provide load-bearing structure and steerable beam pointing functions, and is usually installed in the structural surface of aircraft, warships, and armored vehicles. This paper presents an innovative design of the active skin antenna, which consists of a package layer, control and signal processing layer, and RF (radio frequency) layer. The RF layer is fabricated by low temperature co-fired ceramics, with 64 microstrip antenna elements, tile transmitting and receiving modules, microchannel heat sinks, and feeding networks integrated into a functional block 2.8 mm thick. In this paper, a full-sized prototype of an active skin antenna was designed, fabricated, and tested. Moreover, a coupling analysis method was presented to evaluate the mechanical and electromagnetic performance of the active skin antenna subjected to aerodynamic loads. A deformed experimental system was built to validate the effectiveness of the coupling analysis method, which was also implemented to evaluate the performance of the active skin antenna when subjected to aerodynamic pressure. The fabricated specimen demonstrated structural configuration feasibility, and superior environmental load resistance.

  11. Antenna array geometry optimization for a passive coherent localisation system

    Science.gov (United States)

    Knott, Peter; Kuschel, Heiner; O'Hagan, Daniel

    2012-11-01

    Passive Coherent Localisation (PCL), also known as Passive Radar, making use of RF sources of opportunity such as Radio or TV Broadcasting Stations, Cellular Phone Network Base Stations, etc. is an advancing technology for covert operation because no active radar transmitter is required. It is also an attractive addition to existing active radar stations because it has the potential to discover low-flying and low-observable targets. The CORA (Covert Radar) experimental passive radar system currently developed at Fraunhofer-FHR features a multi-channel digital radar receiver and a circular antenna array with separate elements for the VHF- and the UHF-range and is used to exploit alternatively Digital Audio (DAB) or Video Broadcasting (DVB-T) signals. For an extension of the system, a wideband antenna array is being designed for which a new discone antenna element has been developed covering the full DVB-T frequency range. The present paper describes the outline of the system and the numerical modelling and optimisation methods applied to solve the complex task of antenna array design: Electromagnetic full wave analysis is required for the parametric design of the antenna elements while combinatorial optimization methods are applied to find the best array positions and excitation coefficients for a regular omni-directional antenna performance. The different steps are combined in an iterative loop until the optimum array layout is found. Simulation and experimental results for the current system will be shown.

  12. A Reconfigurable Spiral Antenna for Adaptive MIMO Systems

    Directory of Open Access Journals (Sweden)

    Qian JY

    2005-01-01

    Full Text Available We present a reconfigurable spiral antenna for use in adaptive MIMO systems. The antenna is capable of changing the sense of polarization of the radiated field. It is fabricated by using an RF-MEMS technology compatible with microwave laminate substrates developed within the author's group. The proposed antenna structure is built on a number of rectangular-shaped bent metallic strips interconnected to each other with RF-MEMS actuators. Two senses of polarization, RHCP and LHCP, are achieved by configuring the physical structure of the antenna, that is, by changing the winding sense of the spiral, through judicious activation of MEM actuators. The fabrication process for the monolithic integration of MEM actuators with bent microstrip pixels on RO4003-FR4 microwave laminate substrate is described. The measured and calculated radiation and impedance characteristics of the antenna are given. The operating frequency of the presented antenna design can easily be adjusted to be compatible with popular IEEE networking standards such as 802.11a.

  13. Consistent Long-Time Series of GPS Satellite Antenna Phase Center Corrections

    Science.gov (United States)

    Steigenberger, P.; Schmid, R.; Rothacher, M.

    2004-12-01

    The current IGS processing strategy disregards satellite antenna phase center variations (pcvs) depending on the nadir angle and applies block-specific phase center offsets only. However, the transition from relative to absolute receiver antenna corrections presently under discussion necessitates the consideration of satellite antenna pcvs. Moreover, studies of several groups have shown that the offsets are not homogeneous within a satellite block. Manufacturer specifications seem to confirm this assumption. In order to get best possible antenna corrections, consistent ten-year time series (1994-2004) of satellite-specific pcvs and offsets were generated. This challenging effort became possible as part of the reprocessing of a global GPS network currently performed by the Technical Universities of Munich and Dresden. The data of about 160 stations since the official start of the IGS in 1994 have been reprocessed, as today's GPS time series are mostly inhomogeneous and inconsistent due to continuous improvements in the processing strategies and modeling of global GPS solutions. An analysis of the signals contained in the time series of the phase center offsets demonstrates amplitudes on the decimeter level, at least one order of magnitude worse than the desired accuracy. The periods partly arise from the GPS orbit configuration, as the orientation of the orbit planes with regard to the inertial system repeats after about 350 days due to the rotation of the ascending nodes. In addition, the rms values of the X- and Y-offsets show a high correlation with the angle between the orbit plane and the direction to the sun. The time series of the pcvs mainly point at the correlation with the global terrestrial scale. Solutions with relative and absolute phase center corrections, with block- and satellite-specific satellite antenna corrections demonstrate the effect of this parameter group on other global GPS parameters such as the terrestrial scale, station velocities, the

  14. FINANCIRANJE START - UP PODJETIJ

    OpenAIRE

    Kraner, Simona

    2016-01-01

    V magistrskem delu ugotavljamo specifike start-up podjetij ter njihov vpliv na dostopnost in primernost posameznih virov financiranja. Ko ugotovimo in razdelamo poglavitne specifike, ki na splošno veljajo za start-up podjetja, se lotimo proučevanja faz financiranja, skozi katera start-up prehajajo. Vsako od sedmih tipičnih faz financiranja start-up podjetij opredelimo z vidika značilnosti, ki za start-up podjetja v specifični razvojni fazi veljajo. Prvo polovico teoretičnega dela zaključi...

  15. Measurements of Antenna Parameters in GTEM Cell

    OpenAIRE

    Živković, Zlatko; Šarolić, Antonio

    2010-01-01

    The paper presents the method for measuring parameters (gain, antenna factor, impedance and radiation pattern) of small antennas in GTEM cell, which is a novel method and environment for antenna measurements. In order to investigate the suitability of GTEM cell for this kind of measurement, the measurement results for a biconical dipole, microstrip patch antennas and small loop antenna were compared with those obtained by calibration inside fully absorber lined anechoic site, two-antenna meas...

  16. Microelectromechanical Systems Actuator Based Reconfigurable Printed Antenna

    Science.gov (United States)

    Simons, Rainee N. (Inventor)

    2005-01-01

    A polarization reconfigurable patch antenna is disclosed. The antenna includes a feed element, a patch antenna element electrically connected to the feed element, and at least one microelectromechanical systems (MEMS) actuator, with a partial connection to the patch antenna element along an edge of the patch antenna element. The polarization of the antenna can be switched between circular polarization and linear polarization through action of the at least one MEMS actuator.

  17. Ultra wideband antennas design, methodologies, and performance

    CERN Document Server

    Galvan-Tejada, Giselle M; Jardón Aguilar, Hildeberto

    2015-01-01

    Ultra Wideband Antennas: Design, Methodologies, and Performance presents the current state of the art of ultra wideband (UWB) antennas, from theory specific for these radiators to guidelines for the design of omnidirectional and directional UWB antennas. Offering a comprehensive overview of the latest UWB antenna research and development, this book:Discusses the developed theory for UWB antennas in frequency and time domainsDelivers a brief exposition of numerical methods for electromagnetics oriented to antennasDescribes solid-planar equivalen

  18. Design of a Compact Wideband Antenna Array for Microwave Imaging Applications

    Directory of Open Access Journals (Sweden)

    J. Puskely

    2013-12-01

    Full Text Available In the paper, wideband antenna arrays aimed at microwave imaging applications and SAR applications operating at Ka band were designed. The antenna array feeding network is realized by a low-loss SIW technology. Moreover, we have replaced the large feed network comprised of various T and Y junctions by a simple broadband network of compact size to more reduce losses in the substrate integrated waveguide and also save space on the PCB. The designed power 8-way divider is complemented by a wideband substrate integrated waveguide to a grounded coplanar waveguide transition and directly connected to the antenna elements. The measured results of antenna array are consistent with our simulation. Obtained results of the developed array demonstrated improvement compared to previously developed binary feed networks with microstrip or SIW splitters.

  19. Multifunctional Antenna Techniques

    Science.gov (United States)

    2015-11-25

    which provides data on the state of the UAV to an application on an Android smart phone. Fig. 11. Spiral antenna mounted to a flying wing UAV...operating at 2.4 GHz was constructed using low-cost off-the- shelf components. Fig. 36 shows a diagram of the physical set-up and block diagram of the system... smart phone applications are underway. This includes using the smart phone to control complex RF systems. An ongoing collaboration between the PI

  20. Ultra wide band antennas

    CERN Document Server

    Begaud, Xavier

    2013-01-01

    Ultra Wide Band Technology (UWB) has reached a level of maturity that allows us to offer wireless links with either high or low data rates. These wireless links are frequently associated with a location capability for which ultimate accuracy varies with the inverse of the frequency bandwidth. Using time or frequency domain waveforms, they are currently the subject of international standards facilitating their commercial implementation. Drawing up a complete state of the art, Ultra Wide Band Antennas is aimed at students, engineers and researchers and presents a summary of internationally recog

  1. Nimbus-7 SMMR Antenna Temperatures, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The SMMR Antenna Temperatures (Nimbus-7) data set consists of antenna temperatures from passive microwave radiometers aboard NOAA's Nimbus-7 satellite. The...

  2. Slot-Coupled Barbel Antenna

    DEFF Research Database (Denmark)

    Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne

    2016-01-01

    A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant.......A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant....

  3. Tunable Antennas for Mobile Devices

    DEFF Research Database (Denmark)

    Morris, Art; Barrio, Samantha Caporal Del; Shin, J

    2014-01-01

    Modern mobile terminal design has been driven by the user interface and broadband connectivity. Real world RF performance has substantially fallen recently which impacts data rates, battery life and often causes lost connections. This has been caused by changing antenna location and reduced antenna...

  4. Backfire antennas with dipole elements

    DEFF Research Database (Denmark)

    Nielsen, Erik Dragø; Pontoppidan, Knud

    1970-01-01

    A method is set up for a theoretical investigation of arbitrary backfire antennas based upon dipole structures. The mutual impedance between the dipole elements of the antenna is taken into account, and the field radiated due to a surface wave reflector of finite extent is determined by calculating...

  5. Coupling between minimum scattering antennas

    DEFF Research Database (Denmark)

    Andersen, J.; Lessow, H; Schjær-Jacobsen, Hans

    1974-01-01

    Coupling between minimum scattering antennas (MSA's) is investigated by the coupling theory developed by Wasylkiwskyj and Kahn. Only rotationally symmetric power patterns are considered, and graphs of relative mutual impedance are presented as a function of distance and pattern parameters. Crossed......-dipoles and helices are considered in order to establish a correspondence with simple antenna structures....

  6. Optical antenna enhanced spontaneous emission.

    Science.gov (United States)

    Eggleston, Michael S; Messer, Kevin; Zhang, Liming; Yablonovitch, Eli; Wu, Ming C

    2015-02-10

    Atoms and molecules are too small to act as efficient antennas for their own emission wavelengths. By providing an external optical antenna, the balance can be shifted; spontaneous emission could become faster than stimulated emission, which is handicapped by practically achievable pump intensities. In our experiments, InGaAsP nanorods emitting at ∼ 200 THz optical frequency show a spontaneous emission intensity enhancement of 35 × corresponding to a spontaneous emission rate speedup ∼ 115 ×, for antenna gap spacing, d = 40 nm. Classical antenna theory predicts ∼ 2,500 × spontaneous emission speedup at d ∼ 10 nm, proportional to 1/d(2). Unfortunately, at d < 10 nm, antenna efficiency drops below 50%, owing to optical spreading resistance, exacerbated by the anomalous skin effect (electron surface collisions). Quantum dipole oscillations in the emitter excited state produce an optical ac equivalent circuit current, I(o) = qω|x(o)|/d, feeding the antenna-enhanced spontaneous emission, where q|x(o)| is the dipole matrix element. Despite the quantum-mechanical origin of the drive current, antenna theory makes no reference to the Purcell effect nor to local density of states models. Moreover, plasmonic effects are minor at 200 THz, producing only a small shift of antenna resonance frequency.

  7. The Ultrawideband Leaky Lens Antenna

    NARCIS (Netherlands)

    Bruni, S.; Neto, A.; Marliani, F.

    2007-01-01

    A novel directive and nondispersive antenna is presented: the ultrawideband (UWB) leaky lens. It is based on the broad band Cherenkov radiation occurring at a slot printed between different infinite homogeneous dielectrics. The first part of the paper presents the antenna concept and the UWB design.

  8. Wireless Communication with Multiple Antennas

    Indian Academy of Sciences (India)

    2013-07-05

    Jul 5, 2013 ... Outline of presentation. 1 Information, Uncertainty, and Communication. 2 Capacity of multi-antenna systems. 3 Codes for multi-antenna systems. 4 Well known codes from ECE. 5 Recent patents and concluding remarks. B. Sundar Rajan (ECE). IASc Talk, 05 July 2013. 2 / 31 ...

  9. Antennas for light and plasmons

    NARCIS (Netherlands)

    Dikken, D.J.W.

    2015-01-01

    Antennas have been used for over a century as emitters, scatterers and receivers of electromagnetic waves. All wireless communication devices, such as radio, mobile phones and satellite communication are strongly dependent on the capability of an antenna to localize propagating electromagnetic waves

  10. Minimum Q Electrically Small Antennas

    DEFF Research Database (Denmark)

    Kim, O. S.

    2012-01-01

    Theoretically, the minimum radiation quality factor Q of an isolated resonance can be achieved in a spherical electrically small antenna by combining TM1m and TE1m spherical modes, provided that the stored energy in the antenna spherical volume is totally suppressed. Using closed-form expressions...... for the stored energies obtained through the vector spherical wave theory, it is shown that a magnetic-coated metal core reduces the internal stored energy of both TM1m and TE1m modes simultaneously, so that a self-resonant antenna with the Q approaching the fundamental minimum is created. Numerical results...... for a multiarm spherical helix antenna confirm the theoretical predictions. For example, a 4-arm spherical helix antenna with a magnetic-coated perfectly electrically conducting core (ka=0.254) exhibits the Q of 0.66 times the Chu lower bound, or 1.25 times the minimum Q....

  11. Spectrum Sensing in relation to Distributed Antenna System for Coverage Predictions

    DEFF Research Database (Denmark)

    Kumar, Ambuj; Mihovska, Albena D.; Prasad, Ramjee

    2014-01-01

    (BTS)/Nodes at one location known as BTS hotel and the antennas are distributed all over target area by fiber optic network, is discussed. The very concept of splitting Base Station (BS) from its antenna system and putting it at one location (BS Hotel) and distributing antenna as nodes (Remote Unit......, or RU) that can be easily mounted on any pre-existing support structure that may be a street furniture like public or private street poles, hoardings, facilities or even Shop Display Frame, is very attractive in its own way. The ease of installation, high utilization of network resources, multi...

  12. The Study and Implementation of Electrically Small Printed Antennas for an Integrated Transceiver Design

    Energy Technology Data Exchange (ETDEWEB)

    Speer, Pete [Univ. of Kansas, Lawrence, KS (United States)

    2009-04-28

    This work focuses on the design and evaluation of the inverted-F, meandering-monopole, and loop antenna geometries. These printed antennas are studied with the goal of identifying which is suitable for use in a miniaturized transceiver design and which has the ability to provide superior performance using minimal Printed Circuit Board (PCB) space. As a result, the main objective is to characterize tradeoffs and identify which antenna provides the best compromise among volume, bandwidth and efficiency. For experimentation purposes, three types of meandering-monopole antenna are examined resulting in five total antennas for the study. The performance of each antenna under study is evaluated based upon return loss, operational bandwidth, and radiation pattern characteristics. For our purposes, return loss is measured using the S11-port reflection coefficient which helps to characterize how well the small antenna is able to be efficiently fed. Operational bandwidth is measured as the frequency range over which the antenna maintains 2:1 Voltage Standing Wave Ratio (VSWR) or equivalently has 10-dB return loss. Ansoft High Frequency Structure Simulator (HFSS) is used to simulate expected resonant frequency, bandwidth, VSWR, and radiation pattern characteristics. Ansoft HFSS simulation is used to provide a good starting point for antenna design before actual prototype are built using an LPKF automated router. Simulated results are compared with actual measurements to highlight any differences and help demonstrate the effects of antenna miniaturization. Radiation characteristics are measured illustrating how each antenna is affected by the influence of a non-ideal ground plane. The antenna with outstanding performance is further evaluated to determine its maximum range of communication. Each designs range performance is evaluated using a pair of transceivers to demonstrate round-trip communication. This research is intended to provide a knowledge base which will help

  13. Engine Cold Start

    Science.gov (United States)

    2015-09-01

    UNCLASSIFIED UNCLASSIFIED ENGINE COLD START INTERIM REPORT TFLRF No. 469 by Douglas M. Yost Gregory A. T. Hansen U.S...not return it to the originator. UNCLASSIFIED UNCLASSIFIED ENGINE COLD START INTERIM REPORT TFLRF No. 469 by Douglas M. Yost...TITLE AND SUBTITLE Engine Cold Start 5a. CONTRACT NUMBER W56HZV-09-C-0100 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Douglas

  14. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications.

    Science.gov (United States)

    Eom, Seung-Hyun; Seo, Yunsik; Lim, Sungjoon

    2015-12-10

    In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM) simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch.

  15. Wearable Antennas for Remote Health Care Monitoring Systems

    Directory of Open Access Journals (Sweden)

    Laura Corchia

    2017-01-01

    Full Text Available Remote monitoring of the elderly in telehealth applications requires that the monitoring must not affect the elderly’s regular habits. To ensure this requirement, the components (i.e., sensor and antenna necessary to carry out such monitoring should blend in with the elderly’s daily routine. To this end, an effective strategy relies on employing wearable antennas that can be fully integrated with clothes and that can be used for remotely transmitting/receiving the sensor data. Starting from these considerations, in this work, two different methods for wearable antenna fabrication are described in detail: the first resorts to the combined use of nonwoven conductive fabrics and of a cutting plotter for shaping the fabric, whereas the second considered fabrication method resorts to the embroidery of conductive threads. To demonstrate the suitability of the considered fabrication techniques and to highlight their pros and cons, numerical and experimental results related to different wearable antennas are also reported and commented on. Results demonstrate that the presented fabrication techniques and strategies are very flexible and can be used to obtain low-cost wearable antennas with performance tailored for the specific application at hand.

  16. Correlation properties of dual polarized antennas with finite pattern orthogonality in mobile fading channels

    Directory of Open Access Journals (Sweden)

    G. Armbrecht

    2007-06-01

    Full Text Available Starting from planar broadband log.-per. antenna design, offering the possibility of dual-polarized reception properties, in this article a generalized mathematical approach for rapidly estimating the resulting signal correlation coefficient in a stochastically modeled propagation environment solely based on measured or simulated radiation characteristics of one single antenna element is presented. The obtained results are marking an upper limit and are describing the worst-case scenario according to the signal correlation at the antenna feeding points in terms of line-of-sight (LOS reception in main beam direction. The knowledge of the derived relationship may be helpful especially for antenna designers to combine antenna performance values with the significant communication system performance parameters, as e.g. in case of Multiple-Input Multiple-Output (MIMO and diversity configurations.

  17. Smart Coat with a Fully-Embedded Textile Antenna for IoT Applications.

    Science.gov (United States)

    Loss, Caroline; Gonçalves, Ricardo; Lopes, Catarina; Pinho, Pedro; Salvado, Rita

    2016-06-22

    The Internet of Things (IoT) scenario is strongly related with the advance of the development of wireless sensor networks (WSN) and radio frequency identification (RFID) systems. Additionally, in the WSN context, for a continuous feed, the integration of textile antennas for energy harvesting into smart clothing is a particularly interesting solution when the replacement of batteries is not easy to practice, such as in wearable devices. This paper presents the E-Caption: Smart and Sustainable Coat. It has an embedded dual-band textile antenna for electromagnetic energy harvesting, operating at global system for mobile communication (GSM) 900 and digital cellular system (DCS) 1800 bands. This printed antenna is fully integrated, as its dielectric is the textile material composing the coat itself. The E-Caption illustrates the innovative concept of textile antennas that can be manipulated as simple emblems. Seven prototypes of these "emblem" antennas, manufactured by lamination and embroidering techniques are also presented. It is shown that the orientation of the conductive fabric does not influence the performance of the antenna. It is also shown that the direction and number of the stitches in the embroidery may influence the performance of the antenna. Moreover, the comparison of results obtained before and after the integration of the antenna into cloth shows the integration does not affect the behavior of the antenna.

  18. Cirlularly Polarized Proximity- Fed Microstrip Array Antenna for LAPAN TUBSAT Micro Satellite System

    Directory of Open Access Journals (Sweden)

    Endra Wijaya

    2013-11-01

    Full Text Available The design microstrip of array antenna circular polarization characteristic developed for support LAPAN TUBSAT micro satellite system. The antenna on the micro satellite systems transmit data to ground stations operating at S band frequencies.The antenna is designed for impedance matching at frequencies of 2:25 GHz.The four elements of the square patch antenna array composed using linear methods, where the design of the transmission lines used by federal corporate structure model network consisting of three elements of the quarter wave transformer of a power divider. The feeding techniques for antenna designed using proximity coupling method, which for the type of substrate material used is similar. Circularly polarized antenna characteristics are influenced by the truncated corner pieces on the patch. To design the overall antenna used simulated method of moments in microwave office software applications. The results of measurements and simulations obtained antenna parameters, such as: bandwidth of return loss under 10 dB is 200 MHz (shifted 35%, bandwidth of axial ratio under 3dB is 1.7% and maximum gain directivity is 9 dB. Overall results obtained antenna parameters to meet the specifications of LAPAN TUBSAT micro satellite system.

  19. Design of a Microstrip Bowtie Antenna for Indoor Radio-Communications

    Directory of Open Access Journals (Sweden)

    Fraga-Rosales Hector

    2017-01-01

    Full Text Available In this paper, a microstrip bowtie patch antenna (MBPA for wireless indoor communications is carried out. Here, a microstrip transmission-line feed network was designed in order to match the MBPA. The proposed antenna uses a ground plane with the aim of narrowing down the back lobes in comparison with bowtie sheet antennas, which radiation pattern is omni-directional. The far-field pattern of the antenna was simulated using a finite-element numerical algorithm and obtained by interpolation employing near-field equipment. The experimental results are described in detail intending to agree well with the simulated predictions. The antenna was designed, measured and built and its far field performance was evaluated with a 2.11 GHz resonant frequency. The azimuth and elevation antenna patterns, antenna gain and, the matching frequency were the main parameters obtained to analyze the antenna behaviour. The antenna has a gain approximately equal to 8.77 dBi and its beam-widths are higher than 100° in E plane.

  20. Smart Coat with a Fully-Embedded Textile Antenna for IoT Applications

    Directory of Open Access Journals (Sweden)

    Caroline Loss

    2016-06-01

    Full Text Available The Internet of Things (IoT scenario is strongly related with the advance of the development of wireless sensor networks (WSN and radio frequency identification (RFID systems. Additionally, in the WSN context, for a continuous feed, the integration of textile antennas for energy harvesting into smart clothing is a particularly interesting solution when the replacement of batteries is not easy to practice, such as in wearable devices. This paper presents the E-Caption: Smart and Sustainable Coat. It has an embedded dual-band textile antenna for electromagnetic energy harvesting, operating at global system for mobile communication (GSM 900 and digital cellular system (DCS 1800 bands. This printed antenna is fully integrated, as its dielectric is the textile material composing the coat itself. The E-Caption illustrates the innovative concept of textile antennas that can be manipulated as simple emblems. Seven prototypes of these “emblem” antennas, manufactured by lamination and embroidering techniques are also presented. It is shown that the orientation of the conductive fabric does not influence the performance of the antenna. It is also shown that the direction and number of the stitches in the embroidery may influence the performance of the antenna. Moreover, the comparison of results obtained before and after the integration of the antenna into cloth shows the integration does not affect the behavior of the antenna.

  1. Hybrid Maritime Satellite Communication Antenna

    DEFF Research Database (Denmark)

    Smith, Thomas Gunst

    is incorporated in a parabolic FSS reflector antenna that is investigated by full-wave analysis tools, and the antenna shows performance comparable to conventional reflector antennas within its frequency band of operation. A planar prototype FSS is manufactured and measured with particular attention to the impact......Hybrid antennas for a maritime satellite communication terminal with simultaneous operation at L- and Ka-band have been investigated. The frequency bands of interest are 1; 525:0 1; 660:5 MHz (RX+TX, RHCP), 19:7 20:2 (RX, LHCP) and 29:5 30:0 GHz (TX, RHCP), which are all part of the Inmarsat BGAN...... on the performance of an L-band antenna radiating through the FSS. From these investigations, it is concluded that the FSS antenna concept is well suited for hybrid L- and Ka-band operation. A printed reflectarray antenna with FSS ground-plane is demonstrated. The reflectarray produces a collimated beam as a curved...

  2. Head Start in Action.

    Science.gov (United States)

    Riley, Clara M. D.; Epps, Frances M. J.

    Records and observations from a summer Head Start program, conducted in Los Angeles by Delta Sigma Theta, are delineated in this book. It relates firsthand experiences of the participating personnel as they developed and implemented a Head Start program for some 300 children. The book is divided into three sections. Section I,…

  3. Composite antenna feed

    Science.gov (United States)

    Jakstys, V. J. (Inventor)

    1973-01-01

    A composite antenna feed subsystem concentrated in a small area at the prime focus of the parabola of a satellite parabolic reflector accomodates a plurality of frequency bands. The arrays comprising the subsystem are mounted on the top cover of a communication module. A multimode horn is arranged at the center of the subsystem axis which functions at X- And C-band frequencies, and a cross array consisting of individual elements form the S-band feed, with one arm of the S-band array containing an element mutually shared with the L-band array. Provision is also made for UHF frequencies, and a dipole arrangement for VHF frequencies is arranged around the S-band arms.

  4. Experimental Multiport Bicone Antenna

    Science.gov (United States)

    Eskelinen, Pekka; Ylinen, Juhana

    2013-01-01

    A practical, easily manufactured multiport bicone antenna suitable for many receiving tasks such as direction finding systems can be made by using sharp-edged metal fins on the feeding coax center conductor to provide a tapered transition and connection path to coaxial probes. This construction resembles an arrow's tail. Already four mutually orthogonal fins can give full 360 degree azimuth coverage with suitable -3 dB port pattern overlap. Five experimental constructions working at Ku and Ka bands, each with fractional bandwidths of 23 to 31 per cent, are shown with full dimensional details. Suitable fin tapering is close to the full air gap in the coax and fin thickness should be less than 1/16th of the outer conductor diameter.

  5. Rydberg Dipole Antennas

    Science.gov (United States)

    Stack, Daniel; Rodenburg, Bradon; Pappas, Stephen; Su, Wangshen; St. John, Marc; Kunz, Paul; Simon, Matt; Gordon, Joshua; Holloway, Christopher

    2017-04-01

    Measurements of microwave frequency electric fields by traditional methods (i.e. engineered antennas) have limited sensitivity and can be difficult to calibrate properly. A useful tool to address this problem are highly-excited (Rydberg) neutral atoms which have very large electric-dipole moments and many dipole-allowed transitions in the range of 1-500 GHz. Using Rydberg states, it is possible to sensitively probe the electric field in this frequency range using the combination of two quantum interference phenomena: electromagnetically induced transparency and the Autler-Townes effect. This atom-light interaction can be modeled by the classical description of a harmonically bound electron. The classical damped, driven, coupled-oscillators model yields significant insights into the deep connections between classical and quantum physics. We will present a detailed experimental analysis of the noise processes in making such measurements in the laboratory and discuss the prospects for building a practical atomic microwave receiver.

  6. Mutual Coupling Effects for Radar Cross Section (RCS of a Series-Fed Dipole Antenna Array

    Directory of Open Access Journals (Sweden)

    H. L. Sneha

    2012-01-01

    Full Text Available The estimation of RCS of a phased array depends on various parameters, namely, array geometry, operational frequency, feed network, mutual coupling between the antenna elements and so fourth. This paper presents the estimation of RCS of linear dipole array with series-feed network by tracing the signal path from the antenna aperture into the feed network. The effect of mutual coupling exhibited by the dipole antenna is considered for three configurations namely, side by side, collinear, and parallel in echelon. It is shown that the mutual coupling affects the antenna pattern (and hence RCS significantly for larger scan angles. Further it is inferred that the RCS of phased array can be optimized by (i reducing the length of the dipole, (ii termination of the isolation port of the coupler with a suitable load, and (iii using suitable amplitude distribution.

  7. Metamaterial antennas: the most successful metamaterial technology?

    DEFF Research Database (Denmark)

    Breinbjerg, Olav

    2015-01-01

    The Thomson Reuters Web of Science™ lists more than 1500 journal articles related to metamaterial antennas from 2001 to 2015; this paper overviews some major objectives of such antennas.......The Thomson Reuters Web of Science™ lists more than 1500 journal articles related to metamaterial antennas from 2001 to 2015; this paper overviews some major objectives of such antennas....

  8. 47 CFR 73.816 - Antennas.

    Science.gov (United States)

    2010-10-01

    ... manufacturer. In no event may composite antennas (i.e., antennas that consist of multiple stacked and/or phased... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antennas. 73.816 Section 73.816... Low Power FM Broadcast Stations (LPFM) § 73.816 Antennas. (a) Permittees and licensees may employ...

  9. Thermal Loss in High-Q Antennas

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Bahramzy, Pevand; Svendsen, Simon

    2014-01-01

    Tunable antennas are very promising for future generations of mobile communications, where antennas are required to cover a wide range operating bands. This letter aims at characterizing the loss mechanism of tunable antennas. Tunable antennas typically exhibit a high Quality factor (Q), which can...

  10. Double Structure Broadband Leaky Wave Antenna

    NARCIS (Netherlands)

    Neto, A.; Dijk, R. van; Filippo, M.

    2011-01-01

    A leaky wave antenna contains a first and a second leaky wave antenna structure back to back against each other. Each antenna structure comprises a dielectric body and an elongated wave carrying structure, such as a slot in a conductive ground plane. In each leaky wave antenna structure the body and

  11. Radar Transponder Antenna Systems Evaluation Handbook

    Science.gov (United States)

    2006-07-01

    Trajectory Measurements Group; antenna principles; antenna patterns; EWR 127-1 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as...utility. 15. SUBJECT TERMS Electronic Trajectory Measurements Group; antenna principles; antenna patterns; EWR 127-1 16. SECURITY CLASSIFICATION OF...Considerations of Existing Guideline Documents .......................................... 7-2 7.3 Suggested References To EWR 127-1 Document

  12. 47 CFR 73.510 - Antenna systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 73.510 Section 73.510... Noncommercial Educational FM Broadcast Stations § 73.510 Antenna systems. (a) All noncommercial educational... § 73.316 concerning antenna systems contained in subpart B of this part. (b) Directional antenna. No...

  13. Moths smell with their antennae

    Science.gov (United States)

    Spencer, Thomas; Ballard, Matthew; Alexeev, Alexander; Hu, David

    2015-11-01

    Moths are reported to smell each other from over 6 miles away, locating each other with just 200 airborne molecules. In this study, we investigate how the structure of the antennae influences particle capture. We measure the branching patterns of over 40 species of moths, across two orders of magnitude in weight. We find that moth antennae have 3 levels of hierarchy, with dimensions on each level scaling with body size. We perform lattice-Boltzman simulations to determine optimal flow patterns around antennae branches allowing for capture of small particles.

  14. Smart antennas based on graphene

    Energy Technology Data Exchange (ETDEWEB)

    Aldrigo, Martino; Dragoman, Mircea, E-mail: mircea.dragoman@imt.ro [National Institute for Research and Development in Microtechnology (IMT), P.O. Box 38-160, 023573 Bucharest (Romania); Dragoman, Daniela [Physics Faculty, University of Bucharest, P.O. Box MG-11, 077125 Bucharest (Romania)

    2014-09-21

    We report two configurations of smart graphene antennas, in which either the radiation pattern of the antenna or the backscattering of the periodic metallic arrays is controlled by DC biases that induce metal-insulator reversible transitions of graphene monolayers. Such a transition from a high surface resistance (no bias) to a low surface resistance state (finite bias voltage) causes the radiation pattern of metallic antennas backed with graphene to change dramatically, from omnidirectional to broadside. Moreover, reflectarrays enhance the backscattered field due to the same metal-dielectric transition.

  15. Large inflated-antenna system

    Science.gov (United States)

    Hinson, W. F.; Keafer, L. S.

    1984-01-01

    It is proposed that for inflatable antenna systems, technology feasibility can be demonstrated and parametric design and scalability (scale factor 10 to 20) can be validated with an experiment using a 16-m-diameter antenna attached to the Shuttle. The antenna configuration consists of a thin film cone and paraboloid held to proper shape by internal pressure and a self-rigidizing torus. The cone and paraboloid would be made using pie-shaped gores with the paraboloid being coated with aluminum to provide reflectivity. The torus would be constructed using an aluminum polyester composite that when inflated would erect to a smooth shell that can withstand loads without internal pressure.

  16. Absorption Efficiency of Receiving Antennas

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Frandsen, Aksel

    2005-01-01

    A receiving antenna with a matched load will always scatter some power. This paper sets an upper and a lower bound on the absorption efficiency (absorbed power over sum of absorbed and scattered powers), which lies between 0 and 100% depending on the directivities of the antenna and scatter...... patterns. It can approach 100% as closely as desired, although in practice this may not be an attractive solution. An example with a small endfire array of dipoles shows an efficiency of 93%. Several examples of small conical horn antennas are also given, and they all have absorption efficiencies less than...

  17. Measurement of mobile antenna systems

    CERN Document Server

    Arai, Hiroyuki

    2012-01-01

    If you're involved with the design, installation or maintenance of mobile antenna systems, this thoroughly revised and updated edition of a classic Artech book offers you the most current and comprehensive coverage of all the mandatory measurement techniques you need for your work in the field. This Second Edition presents critical new material in key areas, including radiation efficiency measurement, mobile phone usage position, and MIMO (multiple-input/multiple-output) antennas.This unique resource provides in-depth examinations of all relevant mobile antenna measurement theories, along with

  18. Design and Analysis of Printed Yagi-Uda Antenna and Two-Element Array for WLAN Applications

    Directory of Open Access Journals (Sweden)

    Cai Run-Nan

    2012-01-01

    Full Text Available A printed director antenna with compact structure is proposed. The antenna is fed by a balanced microstrip-slotline and makes good use of space to reduce feeding network area and the size of antenna. According to the simulation results of CST MICROWAVE STUDIO software, broadband characteristics and directional radiation properties of the antenna are explained. The operating bandwidth is 1.8 GHz–3.5 GHz with reflection coefficient less than −10 dB. Antenna gain in band can achieve 4.5–6.8 dBi, and the overall size of antenna is smaller than 0.34λ0×0.58λ0. Then the antenna is developed to a two-element antenna array, working frequency and relative bandwidth of which are 2.15–2.87 GHz and 28.7%, respectively. Compared with antenna unit, the gain of the antenna array has increased by 2 dB. Thus the proposed antenna has characteristics of compact structure, relatively small size, and wideband, and it can be widely used in PCS/UMTS/WLAN/ WiMAX fields.

  19. Design and Fabrication of a Reconfigurable MEMS-Based Antenna

    KAUST Repository

    Martinez, Miguel Angel Galicia

    2011-06-22

    This thesis presents the design and fabrication of a customized in house Micro-Electro-Mechanical-Systems (MEMS) process based on-chip antenna that is both frequency and polarization reconfigurable. It is designed to work at both 60 GHz and 77 GHz through MEMS switches. This antenna can also work in both horizontal and vertical linear polarizations by utilizing a moveable plate. The design is intended for Wireless Personal Area Networks (WPAN) and automotive radar applications. Typical on-chip antennas are inefficient and difficult to reconfigure. Therefore, the focus of this work is to develop an efficient on-chip antenna solution, which is reconfigurable in frequency and in polarization. A fractal bowtie antenna is employed for this thesis, which achieves frequency reconfigurability through MEMS switches. The design is simulated in industry standard Electromagnetic (EM) simulator Ansoft HFSS. A novel concept for horizontal to vertical linear polarization agility is introduced which incorporates a moveable polymer plate. For this work, a microprobe is used to move the plate from the horizontal to vertical position. For testing purposes, a novel mechanism has been designed in order to feed the antenna with RF-probes in both horizontal and vertical positions. A simulated gain of approximately 0 dB is achieved at both target frequencies (60 and 77 GHz), in both horizontal and vertical positions. In all the cases mentioned above (both frequencies and positions), the antenna is well matched (< -10 dB) to the 50 Ω system impedance. Similarly, the radiation nulls are successfully shifted by changing the position of the antenna from horizontal to vertical. The complete design and fabrication of the reconfigurable MEMS antenna has been done at KAUST facilities. Some challenges have been encountered during its realization due to the immaturity of the customized MEMS fabrication process. Nonetheless, a first fabrication attempt has highlighted such shortcomings. According

  20. Novel Compact Spider Microstrip Antenna with New Defected Ground Structure

    Science.gov (United States)

    Ghoname, R. S.; Mohamed, M. A.; Hennawy, A. El.

    2012-08-01

    Two novel Defected Ground Structures (DGS) were first proposed, which have better results than that of the dumbbell (published shape). Using the general model of DGS, its equivalent parameters were extracted. The two new proposed shapes of DGS were then used to design a novel compact spider microstrip antenna to minimize its area. The size of the developed antenna was reduced to about 90.5% of that of the conventional one. This antenna with two different novel shapes of DGS was designed and simulated by using the ready-made software package Zeland-IE3D. Finally, it was fabricated by using thin film and photolithographic technique and measured by using vector network analyzer. Good agreements were found between the simulated and measured results.

  1. FTTA System Demo Using Optical Fiber-Coupled Active Antennas

    Directory of Open Access Journals (Sweden)

    Niels Neumann

    2014-08-01

    Full Text Available The convergence of optical and wireless systems such as Radio-over-Fiber (RoF networks is the key to coping with the increasing bandwidth demands due to the increasing popularity of video and other high data rate applications. A high level of integration of optical technologies enables simple base stations with a fiber-to-the-antenna (FTTA approach. In this paper, we present a complete full-duplex RoF–FTTA system consisting of integrated active fiber-coupled optical receiving and transmitting antennas that are directly connected to a standard single mode fiber optical link. Data rates up to 1 Gbit/s could be shown without advanced modulation formats on a 1.5 GHz carrier frequency. The antennas as well as the whole system are explained and the results of the system experiments are discussed.

  2. Magnetic materials for mobile communication antennas substrate application

    Science.gov (United States)

    Chen, Hui; Liang, Difei; Li, Weijia; Pang, Chao

    2017-11-01

    In this work, 3Ba0.7Sr0.3O·2CoO·10.8Fe2O3 and Ba2Co2Fe12O22 had been fabricated successfully by conventional ceramic process. Crystallographic structure and electromagnetic properties of two kind of hexagonal ferrite with different sintering temperature were investigated. X-ray Diffraction (XRD), Agilent-N5230A Network Analyzer were used to measure ferrite samples. The mobile phone antenna performance was analysed by HFSS. The results revealed that the main phase of two ferrite samples generated at lower temperature due to additive. The optimized parameters of ferrite are sintering temperature at 1000°C. And to emulate antenna model by HFSS find that Z-type and Y-type ferrite substrate can contribute to antenna frequency shifting, radiation efficiency were affected a little.

  3. Group Delay of High Q Antennas

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert Frølund

    2013-01-01

    become an issue, when working with high Q antennas, because of the steep phase shift over the frequency. In this paper, it is measured how large group delay variations can become, when going from a low Q antenna to a high Q antenna. The group delay of a low Q antenna is shown to be around 1.3 ns, whereas...... a high Q antenna has group delay of around 22 ns. It is due to this huge group delay variation characteristics of high Q antennas, that signal distortion might occur in the radio system with high Q antennas....

  4. Analysis and design of low profile multiband multifunctional antenna arrays

    Science.gov (United States)

    Hunsicker, Walker F.

    Light-weight phased array antennas for aerospace and mobile applications require utilizing the same antenna aperture to provide multiple functions with dissimilar radiation pattern specifications (e.g., multiband operation for communications and tracking). Multi-functional antennas provide advantages over aggregate antenna clusters by reducing space requirements, and can aid in the optimal placement of all required apertures to provide adequate isolation between channels. Furthermore, the combination of antenna apertures into a common geometry mitigates co-site installation issues by addressing interference within the integrated radiator design itself as opposed to the extensive analysis which is required to configure multiple radiators in close proximity. The combination of multiple radiators into a single aperture can only be achieved with the proper selection of antenna topology and accompanying feed network design. This research proposes a new technique for the design of multiband arrays in which a common aperture is used. Highlighted by this method is the integration of a tri-band array comprised of an X-band (12 GHz) microstrip patch array on a superstrate above printed dual-band (1 and 2 GHz) slot loop antenna arrays in an octave-spaced lattice. The selection of a ground backing reflector is considered for improved gain and system packaging, but restricts the utility of the design principally due to the lambda/4 depth of the ground plane. Therefore, a novel multiband high impedance surfaces (HIS) is proposed to load the slot apertures for reduced height. The novel techniques proposed here will enable the design of a low profile and conformal single aperture supporting multi-band and multi-functional operations.

  5. Improved Systematic Pointing Error Model for the DSN Antennas

    Science.gov (United States)

    Rochblatt, David J.; Withington, Philip M.; Richter, Paul H.

    2011-01-01

    New pointing models have been developed for large reflector antennas whose construction is founded on elevation over azimuth mount. At JPL, the new models were applied to the Deep Space Network (DSN) 34-meter antenna s subnet for corrections of their systematic pointing errors; it achieved significant improvement in performance at Ka-band (32-GHz) and X-band (8.4-GHz). The new models provide pointing improvements relative to the traditional models by a factor of two to three, which translate to approximately 3-dB performance improvement at Ka-band. For radio science experiments where blind pointing performance is critical, the new innovation provides a new enabling technology. The model extends the traditional physical models with higher-order mathematical terms, thereby increasing the resolution of the model for a better fit to the underlying systematic imperfections that are the cause of antenna pointing errors. The philosophy of the traditional model was that all mathematical terms in the model must be traced to a physical phenomenon causing antenna pointing errors. The traditional physical terms are: antenna axis tilts, gravitational flexure, azimuth collimation, azimuth encoder fixed offset, azimuth and elevation skew, elevation encoder fixed offset, residual refraction, azimuth encoder scale error, and antenna pointing de-rotation terms for beam waveguide (BWG) antennas. Besides the addition of spherical harmonics terms, the new models differ from the traditional ones in that the coefficients for the cross-elevation and elevation corrections are completely independent and may be different, while in the traditional model, some of the terms are identical. In addition, the new software allows for all-sky or mission-specific model development, and can utilize the previously used model as an a priori estimate for the development of the updated models.

  6. Fiber to the antenna

    DEFF Research Database (Denmark)

    Kardaras, Georgios; Soler, José; Brewka, Lukasz Jerzy

    2010-01-01

    During the evolution of mobile networks, reusability of network components has been always a main concern. At the same time, keeping operational and maintenance cost at reasonable levels is a major task. This paper presents and quantifies the advantages of using multimode remote radios capable of...

  7. System-Level Performance of Antenna Arrays in CDMA-Based Cellular Mobile Radio Systems

    Science.gov (United States)

    Czylwik, Andreas; Dekorsy, Armin

    2004-12-01

    Smart antennas exploit the inherent spatial diversity of the mobile radio channel, provide an antenna gain, and also enable spatial interference suppression leading to reduced intracell as well as intercell interference. Especially, for the downlink of future CDMA-based mobile communications systems, transmit beamforming is seen as a well-promising smart antenna technique. The main objective of this paper is to study the performance of diverse antenna array topologies when applied for transmit beamforming in the downlink of CDMA-based networks. In this paper, we focus on uniform linear array (ULA) and uniform circular array (UCA) topologies. For the ULA, we consider three-sector base stations with one linear array per sector. While recent research on downlink beamforming is often restricted to one single cell, this study takes into account the important impact of intercell interference on the performance by evaluating complete networks. Especially, from the operator perspective, system capacity and system coverage are very essential parameters of a cellular system so that there is a clear necessity of intensive system level investigations. Apart from delivering assessments on the performance of the diverse antenna array topologies, in the paper also different antenna array parameters, such as element spacing and beamwidth of the sector antennas, are optimized. Although we focus on the network level, fast channel fluctuations are taken into account by including them analytically into the signal-to-interference calculation.

  8. System-Level Performance of Antenna Arrays in CDMA-Based Cellular Mobile Radio Systems

    Directory of Open Access Journals (Sweden)

    Dekorsy Armin

    2004-01-01

    Full Text Available Smart antennas exploit the inherent spatial diversity of the mobile radio channel, provide an antenna gain, and also enable spatial interference suppression leading to reduced intracell as well as intercell interference. Especially, for the downlink of future CDMA-based mobile communications systems, transmit beamforming is seen as a well-promising smart antenna technique. The main objective of this paper is to study the performance of diverse antenna array topologies when applied for transmit beamforming in the downlink of CDMA-based networks. In this paper, we focus on uniform linear array (ULA and uniform circular array (UCA topologies. For the ULA, we consider three-sector base stations with one linear array per sector. While recent research on downlink beamforming is often restricted to one single cell, this study takes into account the important impact of intercell interference on the performance by evaluating complete networks. Especially, from the operator perspective, system capacity and system coverage are very essential parameters of a cellular system so that there is a clear necessity of intensive system level investigations. Apart from delivering assessments on the performance of the diverse antenna array topologies, in the paper also different antenna array parameters, such as element spacing and beamwidth of the sector antennas, are optimized. Although we focus on the network level, fast channel fluctuations are taken into account by including them analytically into the signal-to-interference calculation.

  9. Lean start-up

    DEFF Research Database (Denmark)

    Rasmussen, Erik Stavnsager; Tanev, Stoyan

    2016-01-01

    The risk of launching new products and starting new firms is known to be extremely high. The Lean Start-up approach is a way of reducing these risks and enhancing the chances for success by validating the products and services in the market with customers before launching it in full scale. The main...... and the final business model. In other words: The start-up must first nail the problem together with the customers, then develop the solution and test, and then in the end scale it to a full-grown business model....

  10. Electrically floating, near vertical incidence, skywave antenna

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.

    2014-07-08

    An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.

  11. Dipoles, unintentional antennas and EMC

    Directory of Open Access Journals (Sweden)

    Berend Danker

    2008-01-01

    Full Text Available Radiated emissions from equipment commonly originate from electronic circuits that act as electric dipoles created by the signal voltage between the signal conductors or as magnetic dipoles formed by the signal current flowing in a loop. Direct emission is mostly small, but circuits often couple to long conductors or large wiring loops which act as antennas and are efficient radiators. A comparable situation exists when short dipole antennas or small wiring loops receive ambient noise (susceptibility. Usually the amplitude of noise sources or the susceptibility of circuits is an invariable. The dipole strength increases with the distance between the conductors and the area. Shielding and proper grounding decreases the interaction via unintentional antennas. Short-circuiting and the insertion of lossy ferrite cores reduce the efficiency of unintentional antennas.

  12. Configurable Conformal Impulse Receive Antenna

    National Research Council Canada - National Science Library

    Kirk, G. H

    2005-01-01

    Among leading-edge research concerns in ultra-wideband (UWB) radiofrequency (RF) methods, it has recently become important to devise antennas to satisfy the following conditions as much as possible: (a) be UWB responsive; (b...

  13. Analysis of biconical microstrip antennas

    Science.gov (United States)

    Lin, Y.; Shafai, L.

    1992-12-01

    Biconical microstrip antennas having a conical patch over a conical substrate are investigated. Analytical expressions for the field distribution inside the conical cavity are developed in a spherical coordinate system and used to determine the eigenvalues of the resonant modes. It is found that, in addition to the axially symmetric modes, TE modes can also resonate which are asymmetric and dependent on the azimuthal angle. For coaxial probe excitation of the cavity its analytic expressions for the field components are determined and used to investigate the antenna input parameters and radiation patterns. The special case of a conical patch microstrip antenna with a planar substrate is also studied. It is shown that, in comparison with circular disk microstrip antennas, a conical patch yields a wider impedance bandwidth and higher gain.

  14. Diversity Gain through Antenna Blocking

    Directory of Open Access Journals (Sweden)

    V. Dehghanian

    2012-01-01

    Full Text Available As part of the typical usage mode, interaction between a handheld receiver antenna and the operator's RF absorbing body and nearby objects is known to generate variability in antenna radiation characteristics through blocking and pattern changes. It is counterintuitive that random variations in blocking can result in diversity gain of practical applicability. This diversity gain is quantified from a theoretical and experimental perspective. Measurements carried out at 1947.5 MHz verify the theoretical predictions, and a diversity gain of 3.1 dB was measured through antenna blocking and based on the utilized measurement setup. The diversity gain can be exploited to enhance signal detectability of handheld receivers based on a single antenna in indoor multipath environments.

  15. Early Head Start Evaluation

    Data.gov (United States)

    U.S. Department of Health & Human Services — Longitudinal information from an evaluation where children were randomly assigned to Early Head Start or community services as usual;direct assessments and...

  16. Head Start Impact Study

    Data.gov (United States)

    U.S. Department of Health & Human Services — Nationally representative, longitudinal information from an evaluation where children were randomly assigned to Head Start or community services as usual;direct...

  17. FEMA DFIRM Station Start

    Data.gov (United States)

    Minnesota Department of Natural Resources — This table contains information about station starting locations. These locations indicate the reference point that was used as the origin for distance measurements...

  18. Improved Gain Microstrip Patch Antenna

    Science.gov (United States)

    2015-08-06

    PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION...08-2015 Publication Improved Gain Microstrip Patch Antenna David A. Tonn Naval Under Warfare Center Division, Newport 1176 Howell St., Code 00L...Distribution A An antenna for mounting on a ground plane includes a dielectric substrate for mounting on the ground plane. A conductive patch

  19. Antenna design for mobile devices

    CERN Document Server

    Zhang, Zhijun

    2017-01-01

    - Integrates state-of-the-art technologies with a special section for step-by-step antenna design - Features up-to-date bio-safety and electromagnetic compatibility regulation compliance and latest standards - Newly updated with MIMO antenna design, measurements and requirements - Accessible to readers of many levels, from introductory to specialist - Written by a practicing expert who has hired and trained numerous engineers

  20. Omnidirectional antenna for radar applications

    Science.gov (United States)

    Vitiello, R.

    The development of an omnidirectional antenna for sidelobe blanking is described. The results of electrical measurements for an S-band and L-band configuration are given. The antenna architecture consists of eight printed radiating elements arranged in a biconical fashion. The single radiating element is a pseudo log periodic microstrip array fed by means of capacitive coupling. Modularity and flexibility are the outstanding characteristics of the design.

  1. Radar techniques using array antennas

    CERN Document Server

    Wirth, Wulf-Dieter

    2013-01-01

    Radar Techniques Using Array Antennas is a thorough introduction to the possibilities of radar technology based on electronic steerable and active array antennas. Topics covered include array signal processing, array calibration, adaptive digital beamforming, adaptive monopulse, superresolution, pulse compression, sequential detection, target detection with long pulse series, space-time adaptive processing (STAP), moving target detection using synthetic aperture radar (SAR), target imaging, energy management and system parameter relations. The discussed methods are confirmed by simulation stud

  2. Living antennas on communication satellites

    DEFF Research Database (Denmark)

    Lumholt, Michael

    2003-01-01

    Crises change the global pattern of communication. The communications problems occur because the satellites are optimized to cover specific geographic areas, and these areas cannot be altered once the satellites are in Earth orbit. An effective solution to the problem is to equip communication...... satellites with "living" antennas that can adjust their radiation coverage areas according to the new demands. The development of living antennas is, therefore, among the focus areas identified and supported by the European Space Agency, ESA....

  3. Getting started with Unity

    CERN Document Server

    Felicia, Patrick

    2013-01-01

    Getting Started with Unity is written in an easy-to-follow tutorial format.""Getting Started with Unity"" is for[ 3D game developers[/color] who would like to learn how to use Unity3D and become familiar with its core features. This book is also suitable for intermediate users who would like to improve their skills. No prior knowledge of Unity3D is required.

  4. Direction of Arrival Estimation with a Novel Single-Port Smart Antenna

    Directory of Open Access Journals (Sweden)

    Chen Sun

    2004-08-01

    Full Text Available A novel direction of arrival (DOA estimation technique that uses the conventional multiple-signal classification (MUSIC algorithm with periodic signals is applied to a single-port smart antenna. Results show that the proposed method gives a high-resolution (1 degree DOA estimation in an uncorrelated signal environment. The novelty lies in that the MUSIC algorithm is applied to a simplified antenna configuration. Only 1 analogue-to-digital converter (ADC is used in this antenna, which features low power consumption, low cost, and ease of fabrication. Modifications to the conventional MUSIC algorithm do not bring much additional complexity. The proposed technique is also free from the negative influence by the mutual coupling among antenna elements. Therefore, it offers an economical way to extensively implement smart antennas into the existing wireless mobile communications systems, especially at the power consumption limited mobile terminals such as laptops in wireless networks.

  5. Reconfigurable micromachined antenna with polarization diversity for mm-wave applications

    KAUST Repository

    Sallam, Mai O.

    2012-03-01

    In this paper a novel MEMS antenna with reconfigurable polarization operating at 60 GHz is presented. This antenna can provide vertical linear polarization, horizontal linear polarization, left hand circular polarization (LHCP), or right hand circular polarization (RHCP) based on the states of the switches present in the feeding network. The proposed antenna is characterized by having its radiating elements isolated from the feeding circuitry via a ground plane without the need for wafer bonding or hybrid integration. Such advantage results in good electric performance while maintains low fabrication cost. The antenna parameters are optimized using HFSS and the results are cross-validated using CST. The good agreement between the two simulators, confirms that the proposed antenna enjoys attractive radiation characteristics for all polarization senses. © 2012 IEEE.

  6. Review on Millimeter Wave Antennas- Potential Candidate for 5G Enabled Applications

    Directory of Open Access Journals (Sweden)

    M. A. Matin

    2016-12-01

    Full Text Available The millimeter wave (mmWave band is considered as the potential candidate for high speed communication services in 5G networks due to its huge bandwidth. Moreover, mmWave frequencies lead to miniaturization of RF front end including antennas. In this article, we provide an overview of recent research achievements of millimeter-wave antenna design along with the design considerations for compact antennas and antennas in package/on chip, mostly in the 60 GHz band is described along with their inherent benefits and challenges. A comparative analysis of various designs is also presented. The antennas with wide bandwidth, high-gain, compact size and low profile with easiness of integration in-package or on-chip with other components are required for 5G enabled applications.

  7. Characterization of polymer silver pastes for screen printed flexible RFID antennas

    Science.gov (United States)

    Janeczek, Kamil; Jakubowska, Małgorzata; Futera, Konrad; MłoŻniak, Anna; Kozioł, GraŻyna; Araźna, Aneta

    Radio Frequency Identification (RFID) systems have become more and more popular in the last few years because of their wide application fields, such as supply chain management and logistics. To continue their development further investigations of new conductive materials for fabrication of RFID transponders' antennas are necessary to be carried out. These materials should provide high flexibility and good radiation performance of printed antennas. In this paper, two polymer silver pastes based on silver flakes were characterized with regard to manufacturing of flexible RFID antennas with screen printing technique. Foil and paper were used as a substrate materials. Surface profile of the printed antennas was measured using an optical profilometer and their resistance was measured with a four-point-probe method. Antenna flexibility was evaluated in cyclic bending tests and its performance with reflection coefficient measurements with the use of differential probe connected to a vector network analyzer. In addition, a maximum read distance of a fabricated RFID transponder was measured.

  8. Electromagnetic antenna modeling (EAM) system

    Science.gov (United States)

    Packer, Malcolm; Powers, Robert; Tsitsopoulos, Paul

    1994-12-01

    The determination of foreign communications capabilities and intent is an important assessment function performed by the USAF National Air Intelligence Center (NAIC). In this context, Rome Laboratory became the NAIC engineering agent for the development of an NAIC requirement for the rapid analysis and evaluation of antenna structures based on often vague to sometimes detailed dimensional information. To this end, the Rome Laboratory sponsored development of the Electromagnetic Antenna Modeling (EAM) System, a state-of-the-art Pascal program with an MS Windows graphical user interface (GUI) pre- and post-processor. Users of NAIC capabilities initiate antenna analysis efforts that range from simple parametric studies to more complex, detailed antenna design and communication-system evaluations. Accordingly, EAM provides a modeling capability 'matched' to the sophistication of the individual analyst, with features appropriate for users ranging from nontechnical analysts to experienced antenna engineers. This capability is particularly valuable in the military-intelligence environment, in which high-speed assessments are required. In particular, EAM meets the specific antenna-analysis requirements of NAIC with a versatile graphical user interface.

  9. Third generation of correlators for six antennas

    Science.gov (United States)

    Torres, Marc

    2000-07-01

    The technical evolution of the correlators of the Plateau de Bure interferometer since the first fringes, 14 years ago, is shortly presented. The progressive addition of antennas over this period has allowed the Grenoble correlator group to undertake several 'start-from-scratch' designs, which have replaced on-site equipment as it came obsolete. The tradeoff between design cycle time and lifetime of such equipment is discussed. The latest design is described in detail. The new correlator can be set to analyze up to eight simultaneous windows, adjustable in size and center frequency, thanks to a 2 X 220 MHz image rejection mixer. Advantages of analog IF processing are presented. The frequency plan of the IF processor has been designed to be fully compatible with MarkIV VLBI recording. The correlator is then used to sum up the signals of the 6 antennas over 256 MHz. The digital section mainly uses an IRAM-designed low-power, low-cost ASIC. Delay lines use FPGA's and phase rotators use DDS's. Surface-mount technology is used everywhere. A commercial CPU module runs the real-time software under Linux. A 21-slot VME chassis hosts the hardware. Test results and measurements of performance on the full-size machine are presented. The difficulties encountered in achieving this kind of machine within schedule in today's industrial environment are retrospectively analyzed.

  10. Feed Structure For Antennas

    Science.gov (United States)

    Fink, Patrick W. (Inventor); Chu, Andrew W. (Inventor); Dobbins, Justin A. (Inventor); Lin, Greg Y. (Inventor)

    2005-01-01

    A novel feed structure, for an antenna having a resonant electric field structure, comprising a patch element, an integrated circuit attached to the patch element, at least one inner conductor electrically connected to and terminating at the integrated circuit on a first end of the at least one inner conductor, wherein the at least one inner conductor extends through and is not electrically connected to the patch element, and wherein the at least one inner conductor is available for electrical connectivity on a second end of the at least one inner conductor, and an outer conductor electrically connected to and terminating at the patch element on a first end of the outer conductor, wherein the outer conductor is available for electrical connectivity on a second end of the outer conductor, and wherein the outer conductor concentrically surrounds the at least one inner conductor from the second end of the at least one inner conductor available for electrical connectivity to the first end of the outer conductor terminating at the patch element.

  11. Performance enhancement of implantable medical antenna using differential feed technique

    Directory of Open Access Journals (Sweden)

    Shankar Bhattacharjee

    2016-03-01

    Full Text Available The health care industry is continuously revolutionizing and advancing towards developing more efficient system suitable for human body. Today implantable devices have become a more interesting topic in health care services which primarily started with the pacemakers. Since then it is continuously evolving due to its non-invasive nature, instant monitoring and diagnosis, and periodic simulation. The main goal of these implantable devices is to efficiently monitor or inspect various ailments in the body and then transmits this to the server or base station. For proper communication between the implant and the base station, antenna design is of prime importance. In this paper MEMS based differentially fed dual band antenna has been proposed and can be used both in Medical Implant Communication Service (MICS band for transmission of data and industrial, scientific and medical (ISM band for wake-up purpose. The proposed antenna has been simulated for free space scenario and has been found to radiate in both MICS & ISM band with S11 of −17.62 dB and −14.31 dB respectively. Subsequently the antenna is inserted within a skin mimicking model with equivalent dielectric features and the results show variation in radiation characteristics between free space condition and within skin phantom. The design of the antenna has been optimized in such a way that minimum deviation occurs between the two conformal conditions. With the use of differential feeding technique performance of the antenna is quite enhanced in terms of various parameters when compared with single feed.

  12. Antenna Miniaturization in Complex Electromagnetic Environments

    DEFF Research Database (Denmark)

    Zhang, Jiaying

    with stringent specifications makes the antenna size reduction a significant challenge. Antenna miniaturization is thus one of the key technologies in designing a successful wireless unit for the hearing-aid application. This dissertation is focused on three areas that are related to the integration of a wire......- less communication system into the heading-aids, and these are the antenna miniaturization, the measurement techniques for electrically small antennas and the influence of complex environments on the characteristics of electrically small antennas, respectively. Antenna Miniaturization......In this dissertation, we present several novel designs of electrically small loop antennas for the hearing-aid application. First antenna design is a two-dimensional (2-D) planar differential-fed electrically small loop. The working mechanism of this antenna is based on the capacitive loading and the induc- tive...

  13. 77 GHz MEMS antennas on high-resistivity silicon for linear and circular polarization

    KAUST Repository

    Sallam, M. O.

    2011-07-01

    Two new MEMS antennas operating at 77 GHz are presented in this paper. The first antenna is linearly polarized. It possesses a vertical silicon wall that carries a dipole on top of it. The wall is located on top of silicon substrate covered with a ground plane. The other side of the substrate carries a microstrip feeding network in the form of U-turn that causes 180 phase shift. This phase-shifter feeds the arms of the dipole antenna via two vertical Through-Silicon Vias (TSVs) that go through the entire wafer. The second antenna is circularly polarized and formed using two linearly polarized antennas spatially rotated with respect to each other by 90 and excited with 90 phase shift. Both antennas are fabricated using novel process flow on a single high-resistivity silicon wafer via bulk micromachining. Only three processing steps are required to fabricate these antennas. The proposed antennas have appealing characteristics, such as high polarization purity, high gain, and high radiation efficiency. © 2011 IEEE.

  14. COMPACT DUAL-BAND INVERTED L SHAPED MONOPOLE ANTENNA FOR WLAN APPLICATIONS

    Directory of Open Access Journals (Sweden)

    K Sumathi

    2015-12-01

    Full Text Available A highly compact and an optimized design of an Inverted L shaped printed monopole antenna with a simple compact ground plane is proposed. To make the designed antenna suitable for implantation it is embedded in FR-4 substrate and is presented. The antenna is designed for dual-band operation at 2.4GHz and 5.2GHz. It is suitable for Wireless Local Area Network (WLAN applications with return loss (S11 < -10dB. The antenna has two different resonant current paths that support two resonances at 2.44GHz and 5.18GHz (forming an F-shaped structure. The size of the antenna is 32.5mm × 19.6mm × 1.6mm. The antenna design is simulated using the tool Advanced Design System (ADS 2014. This antenna design has good return loss and radiation characteristics in both the required frequency bands. The radiation pattern obtained from the proposed antenna is an Omni directional radiation pattern in the E and H plane over the frequency ranges 2.4GHz and 5.2GHz.

  15. Design of a rectenna system for GSM-900 band using novel broadside 2 × 1 array antenna

    Directory of Open Access Journals (Sweden)

    Manish Singh

    2017-05-01

    Full Text Available In this study, a rectenna operating at the GSM-900 frequency band has been fabricated and tested. This rectenna composed of a 2 × 1 T-shaped monopole array antenna and an energy processing circuit. In order to reduce the gap between adjacent antenna elements in the array structure, the proposed array antenna uses a ground stub. Compared with other array antennas, the proposed array antenna with the ground stub reduces the size up to 50% without affecting the gain and bandwidth. An antenna prototype is fabricated and experimentally tested. The measured antenna's gain and bandwidth are 3.2 and 152 MHz, respectively, hence showing its suitability for radio-frequency (RF energy harvesting application. For this to be feasible, the developed array antenna is matched with the rectifier at GSM-900 using a single stub matching network. The measured result demonstrates that the proposed rectifier circuit offers the conversion efficiency of 21.2 and 63.6% for an input power of −20 and 0 dBm, respectively. Finally, the rectifier performance is attested experimentally with the developed array antenna. The rectenna's measured RF-to-dc conversion efficiency was found to be 60% at the far-field distance from the transmitting antenna.

  16. Vehicle antenna development for mobile satellite applications

    Science.gov (United States)

    Woo, K.

    1988-01-01

    The paper summarizes results of a vehicle antenna program at JPL in support of a developing U.S. mobile satellite services (MSS) designed to provide telephone and data services for the continental United States. Two classes of circularly polarized vehicle antennas have been considered for the MSS: medium-gain, satellite-tracking antennas with 10-12-dBic gain; and low-gain, azimuthally omnidirectional antennas with 3-5-dBic gain. The design and performance of these antennas are described, and the two antennas are shown to have peculiar advantages and disadvantages.

  17. Let's play with the parabolic antenna!

    Science.gov (United States)

    Ishihara, Yuko

    2006-03-01

    By collaborating with the Nobeyama Radio Observatory, we developed a teaching material where one can play and learn how a parabolic antenna collects radio waves. The antenna is now on exhibit at Koriyama City Fureai Science Center. Superballs help the user to visualize the mechanism of a parabolic antenna. The antenna used in the exhibit was originally a part of a radio telescope. More than a year has passed since the development and the exhibition. We report about the applied use of the antenna inside and outside our science center and about parabolic antennas in other museums and observatories.

  18. Modern lens antennas for communications engineering

    CERN Document Server

    Thornton, John

    2012-01-01

    The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

  19. VAlidation STandard antennas: Past, present and future

    DEFF Research Database (Denmark)

    Drioli, Luca Salghetti; Ostergaard, A; Paquay, M

    2011-01-01

    designed for validation campaigns of antenna measurement ranges. The driving requirements of VAST antennas are their mechanical stability over a given operational temperature range and with respect to any orientation of the gravity field. The mechanical design shall ensure extremely stable electrical....../V-band of telecom satellites. The paper will address requirements for future VASTs and possible architecture for multi-frequency Validation Standard antennas........ In the beginning, ad-hoc available antennas were shipped around the various ranges. Soon it became clear that the comparisons were restricted by the properties of the antenna. The European Space Agency (ESA) stimulated and supported the development of a dedicated VAlidation STandard (VAST) antenna, specifically...

  20. The Italian VLBI Network: First Results and Future Perspectives

    Science.gov (United States)

    Stagni, Matteo; Negusini, Monia; Bianco, Giuseppe; Sarti, Pierguido

    2016-12-01

    A first 24-hour Italian VLBI geodetic experiment, involving the Medicina, Noto, and Matera antennas, shaped as an IVS standard EUROPE, was successfully performed. In 2014, starting from the correlator output, a geodetic database was created and a typical solution of a small network was achieved, here presented. From this promising result we have planned new observations in 2016, involving the three Italian geodetic antennas. This could be the beginning of a possible routine activity, creating a data set that can be combined with GNSS observations to contribute to the National Geodetic Reference Datum. Particular care should be taken in the scheduling of the new experiments in order to optimize the number of usable observations. These observations can be used to study and plan future experiments in which the time and frequency standards can be given by an optical fiber link, thus having a common clock at different VLBI stations.

  1. Microwave sensor for tangerine classification based on coupled-patch antennas

    Science.gov (United States)

    Leekul, Prapan; Chivapreecha, Sorawat; Krairiksh, Monai

    2016-08-01

    This paper deals with a microwave sensor for classifying tangerines by flavour using coupled-patch antennas. The operating frequency of the antennas is 2.45 GHz. The sensor determines the flavour of each tangerine by measuring the magnitudes of coupled signals of the antennas with the tangerine fruit at the centre. The sorting is carried out using an artificial neural network implemented on a field programmable gate array. The classification performance of the sensor is 95% accurate, so it has potential for use in sorting tangerines by flavour. In addition, the system uncertainty is analysed to determine optimal operating conditions.

  2. ATLAS starts moving in

    CERN Multimedia

    2004-01-01

    The first large active detector component was lowered into the ATLAS cavern on 1 March. It consisted of the 8 modules forming the lower part of the central barrel of the tile hadronic calorimeter. The work of assembling the barrel, which comprises 64 modules, started the following day.

  3. Jump Starting Entrepreneurship

    DEFF Research Database (Denmark)

    Burcharth, Ana Luiza Lara De Araújo; Smith, Pernille; Frederiksen, Lars

    -hanging opportunity seeking entrepreneurs”, and 3) the “jump-start entrepreneurs”. Whereas the two first categories could be expected, the third one shows that, despite hesitance to be self-employed, being uneasy with it, risk adverse and having strong identification to the previous organization, these entrepreneurs...

  4. Waco Head Start Program.

    Science.gov (United States)

    Porter, Para

    The Economic Opportunity Act of 1964 led to the formation of three separate Head Start Programs in Waco, Texas. The first year, 1,500 children were involved. Of these, 40 percent were Negro, 30 percent Latin American, and 30 percent white. All teachers received a week of preparatory study at the University of Texas. The program involved four areas…

  5. Starting up the upstarts.

    Science.gov (United States)

    Greene, J

    1997-12-20

    Venture capitalists pour $1 billion a year into health care--and that investment may be the most overlooked indicator of new business opportunities. Signs show that companies focused on consolidation and cost-cutting are off the A list for risk capital. Instead, venture capitalists are targeting start-ups that save money on the front lines by truly managing care.

  6. Getting started with UDOO

    CERN Document Server

    Palazzetti, Emanuele

    2015-01-01

    If you are an Android developer who wants to learn how to use UDOO to build Android applications that are capable of interacting with their surrounding environment, then this book is ideal for you. Learning UDOO is the next great step to start building your first real-world prototypes powered by the Android operating system.

  7. Getting started with Go

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    No, not the Chinese boardgame, the programming language that ironically Google made difficult to google for. You may have heard of Golang, and are wondering whether you should learn it. The answer is that of course you should, and this talk should explain why and point you at the best resources to get started.

  8. Evaluation of Concrete Consolidation: DSS-35 Antenna Reinforced Concrete Pedestal, Canberra Deep Space Communications Complex, Australia

    Science.gov (United States)

    Saldua, B. P.; Dodge, E. C.; Kolf, P. R.; Olson, C. A.

    2016-02-01

    Antenna structures for the Deep Space Network track spacecraft that are millions of miles away. Therefore, these structures have tight specifications for translation, rotation, and differential settlement. This article presents several nondestructive test methods that were used to evaluate, locate, and repair imperfections in the reinforced concrete pedestal that supports the DSS-35 antenna structure. These methods include: (1) impulse response (IR), (2) ultrasonic shear-wave tomography (MIRA), and (3) ground-penetrating radar (GPR).

  9. Design of LTCC Based Fractal Antenna

    KAUST Repository

    AdbulGhaffar, Farhan

    2010-09-01

    The thesis presents a Sierpinski Carpet fractal antenna array designed at 24 GHz for automotive radar applications. Miniaturized, high performance and low cost antennas are required for this application. To meet these specifications a fractal array has been designed for the first time on Low Temperature Co-fired Ceramic (LTCC) based substrate. LTCC provides a suitable platform for the development of these antennas due to its properties of vertical stack up and embedded passives. The complete antenna concept involves integration of this fractal antenna array with a Fresnel lens antenna providing a total gain of 15dB which is appropriate for medium range radar applications. The thesis also presents a comparison between the designed fractal antenna and a conventional patch antenna outlining the advantages of fractal antenna over the later one. The fractal antenna has a bandwidth of 1.8 GHz which is 7.5% of the centre frequency (24GHz) as compared to 1.9% of the conventional patch antenna. Furthermore the fractal design exhibits a size reduction of 53% as compared to the patch antenna. In the end a sensitivity analysis is carried out for the fractal antenna design depicting the robustness of the proposed design against the typical LTCC fabrication tolerances.

  10. A notch-wire composite antenna for polarization diversity reception

    OpenAIRE

    Kuga, Nobuhiro; Arai, H; Goto, N

    1998-01-01

    This paper presents a notch-wire composite antenna for polarization diversity reception in an indoor base-station system, A three-notched disk antenna and a wire antenna are proposed as component antennas for the horizontal and the vertical polarization, respectively. These component antennas are unified as a single composite diversity antenna by mounting the wire antenna on the notched disk. Antenna characteristics are calculated using the method of moments (MoM) with wire grid models and ex...

  11. Prototyping Neuroadaptive Smart Antenna for 3G Wireless Communications

    Directory of Open Access Journals (Sweden)

    To William

    2005-01-01

    Full Text Available This paper describes prototyping of a neuroadaptive smart antenna beamforming algorithm using hardware-software implemented RBF neural network and FPGA system-on-programmable-chip (SoPC approach. The aim is to implement the adaptive beamforming unit in a combination of hardware and software by estimating its performance against the fixed real-time constraint based on IMT-2000 family of 3G cellular communication standards.

  12. Compact Low Frequency Radio Antenna

    Science.gov (United States)

    Punnoose, Ratish J.

    2008-11-11

    An antenna is disclosed that comprises a pair of conductive, orthogonal arches and a pair of conductive annular sector plates, wherein adjacent legs of each arch are fastened to one of the annular sector plates and the opposite adjacent pair of legs is fastened to the remaining annular sector plate. The entire antenna structure is spaced apart from a conductive ground plane by a thin dielectric medium. The antenna is driven by a feed conduit passing through the conductive ground plane and dielectric medium and attached to one of the annular sector plates, wherein the two orthogonal arched act as a pair of crossed dipole elements. This arrangement of elements provides a radiation pattern that is largely omni-directional above the horizon.

  13. Characterization of biconical transmitting antennas

    Science.gov (United States)

    Grimes, Dale M.; Badii, Vahid; Tomiyama, Ken

    1991-01-01

    We have obtained a general, numerical solution of an ideal biconical transmitting antenna, with arbitrary arm length and conic angle. The solution evaluates the field coefficients associated with the electric multipolar expansion terms both within the antenna region and external to it; the set must necessarily be truncated, and we truncate our set with 16 terms. From the field coefficients we obtain surface current and charge densities resulting from a normalized input current, for several antennas. We evaluate resonant frequencies versus cone angle for the first three resonances. Using a normalized input voltage, we obtain the complex power at all radii; conservation of energy, in turn, permits us to solve for the reactive energy of the field per unit radius.

  14. Biogenic Amines in Insect Antennae

    Directory of Open Access Journals (Sweden)

    Marianna I. Zhukovskaya

    2017-06-01

    Full Text Available Insect antenna is a multisensory organ, each modality of which can be modulated by biogenic amines. Octopamine (OA and its metabolic precursor tyramine (TA affect activity of antennal olfactory receptor neurons. There is some evidence that dopamine (DA modulates gustatory neurons. Serotonin can serve as a neurotransmitter in some afferent mechanosensory neurons and both as a neurotransmitter and neurohormone in efferent fibers targeted at the antennal vessel and mechanosensory organs. As a neurohormone, serotonin affects the generation of the transepithelial potential by sensillar accessory cells. Other possible targets of biogenic amines in insect antennae are hygro- and thermosensory neurons and epithelial cells. We suggest that the insect antenna is partially autonomous in the sense that biologically active substances entering its hemolymph may exert their effects and be cleared from this compartment without affecting other body parts.

  15. Multifrequency Printed Antennas Loaded with Metamaterial Particles

    Directory of Open Access Journals (Sweden)

    D. Segovia-Vargas

    2009-06-01

    Full Text Available This paper provides a review of printed antennas loaded with metamaterial particles. This novel technique allows developing printed antennas with interesting features such as multifrequency (simultaneous operation over two or more frequency bands and multifunctionality (e. g. radiation pattern diversity. Moreover, compactness is also achieved and the main advantages of conventional printed antennas (light weight, low profile, low cost ... are maintained. Different types of metamaterial-loaded printed antennas are reviewed: printed dipoles and patch antennas. Several prototypes are designed, manufactured and measured showing good results. Furthermore, simple but accurate equivalent models are proposed. These models allow an easy and quick design of metamaterial-loaded printed antennas. Finally, two interesting applications based on the proposed antennas are reviewed: the patch antennas are used as radiating elements of emerging active RFID systems in the microwave band and the metamaterial-loaded printed dipoles are employed to increase the performance of log-periodic arrays.

  16. Mode-matching for Optical Antennas

    CERN Document Server

    Feichtner, Thorsten; Hecht, Bert

    2016-01-01

    The emission rate of a point dipole can be strongly increased in presence of a well-designed optical antenna. Yet, optical antenna design is largely based on radio-frequency rules, ignoring e.g.~ohmic losses and non-negligible field penetration in metals at optical frequencies. Here we combine reciprocity and Poynting's theorem to derive a set of optical-frequency antenna design rules for benchmarking and optimizing the performance of optical antennas driven by single quantum emitters. Based on these findings a novel plasmonic cavity antenna design is presented exhibiting a considerably improved performance compared to a reference two-wire antenna. Our work will be useful for the design of high-performance optical antennas and nanoresonators for diverse applications ranging from quantum optics to antenna-enhanced single-emitter spectroscopy and sensing.

  17. VLBI Antenna Calibration via GPS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to investigate and develop an inexpensive system to determine: 1)VLBI antenna properties such as axis-offset, non-intersection of axis and antenna...

  18. Getting started with OrientDB

    CERN Document Server

    Tesoriero, Claudio

    2013-01-01

    A standard tutorial aimed at making you an OrientDB expert, through the use of practical examples, explained in a step-by-step format.Getting Started with OrientDB 1.3.0 is great for database designers, developers, and systems engineers. It is assumed that you are familiar with NoSQL concepts, Java, and networking principles.

  19. Application of the SWE-to-PWE antenna diagnostics technique to an offset reflector antenna

    DEFF Research Database (Denmark)

    Cappellin, Cecilia; Frandsen, Aksel; Breinbjerg, Olav

    2008-01-01

    Electrical and mechanical errors in an antenna may seriously affect the antenna's performance. Although their presence is usually detected by anomalies in the antenna's far-field pattern, their identification is normally possible only through an analysis of the antenna's extreme near field...

  20. Design considerations for low antenna correlation and mutual coupling reduction in multi antenna terminals

    DEFF Research Database (Denmark)

    Thaysen, Jesper; Jakobsen, Kaj Bjarne

    2007-01-01

    The influence of mutual coupling on the envelope correlation between two identical planar inverted F-antennas (PIFA) are investigated. The capacity of a multiple-input multiple-output (MIMO) antenna system strongly depends on the correlation between the antennas. By placing two antennas in a fixe...

  1. Accurate determination of antenna directivity

    DEFF Research Database (Denmark)

    Dich, Mikael

    1997-01-01

    The derivation of a formula for accurate estimation of the total radiated power from a transmitting antenna for which the radiated power density is known in a finite number of points on the far-field sphere is presented. The main application of the formula is determination of directivity from power......-pattern measurements. The derivation is based on the theory of spherical wave expansion of electromagnetic fields, which also establishes a simple criterion for the required number of samples of the power density. An array antenna consisting of Hertzian dipoles is used to test the accuracy and rate of convergence...

  2. 47 CFR 73.685 - Transmitter location and antenna system.

    Science.gov (United States)

    2010-10-01

    ... antenna system. In the case of a composite antenna composed of two or more individual antennas, this means that the patterns for the composite antenna, not the patterns for each of the individual antennas, must... 47 Telecommunication 4 2010-10-01 2010-10-01 false Transmitter location and antenna system. 73.685...

  3. 47 CFR 73.6025 - Antenna system and station location.

    Science.gov (United States)

    2010-10-01

    ..., including the manufacturer and model number of the proposed directional antenna. In the case of a composite antenna composed of two or more individual antennas, the antenna should be described as a “composite... composite antenna composed of two or more individual antennas, this means that the patterns for the...

  4. Gain Estimation of Doubly Curved Reflector Antenna

    Directory of Open Access Journals (Sweden)

    V. Schejbal

    2008-09-01

    Full Text Available A simple formula of approximate gain estimation is verified for the doubly curved reflector antenna. Numerical simulations using physical optics and experimental results of the shaped-beam doubly curved reflector antenna are compared with the simple approximation of gain. That approximation could be very valuable for system engineers to accurately estimate antenna gain and coverage pattern and perform EMC calculations (estimations of interferences and susceptibilities even for the operation and out of operation frequency bands of shapedbeam antenna.

  5. Rectangular dielectric resonator antennas theory and design

    CERN Document Server

    Yaduvanshi, Rajveer S

    2016-01-01

    This book covers resonating modes inside device and gives insights into antenna design, impedance and radiation patterns. It discusses how higher-order modes generation and control impact bandwidth and antenna gain. The text covers new approaches in antenna design by investigation hybrid modes, H_Z and E_Z fields available simultaneously, and analysis and modelling on modes with practical applications in antenna design. The book will be prove useful to students, researchers and professionals alike.

  6. Estimation of complex permittivity using loop antenna

    DEFF Research Database (Denmark)

    Lenler-Eriksen, Hans-Rudolph; Meincke, Peter

    2004-01-01

    A method for estimating the complex permittivity of materials in the vicinity of a loop antenna is proposed. The method is based on comparing measured and numerically calculated input admittances for the loop antenna.......A method for estimating the complex permittivity of materials in the vicinity of a loop antenna is proposed. The method is based on comparing measured and numerically calculated input admittances for the loop antenna....

  7. Inductively Shorted Bicone Fed Tapered Dipole Antenna

    Science.gov (United States)

    2012-05-23

    DATES COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Inductively Shorted Bicone Fed Tapered Dipole Antenna 5a. CONTRACT NUMBER 5b. GRANT...Attorney Docket No. 84449 1 INDUCTIVELY SHORTED BICONE FED TAPERED DIPOLE ANTENNA STATEMENT OF GOVERNMENT INTEREST [0001] The invention described...Invention [0003] The invention generally relates to RF antennas and more specifically to bicone and dipole antennas. (2) Description of the Prior Art

  8. Cylindrical Antenna Using Near Zero Index Metamaterial

    Science.gov (United States)

    2012-07-24

    about their vertical axes could also be used. These include, but are not be limited to, dipole antennas and biconical antennas . [0022] The anomalous...COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Cylindrical Antenna Using Near Zero Index Metamaterial 5a. CONTRACT NUMBER 5b. GRANT...1 Attorney Docket No. 101380 CYLINDRICAL ANTENNA USING NEAR ZERO INDEX METAMATERIAL STATEMENT OF GOVERNMENT INTEREST [0001] The invention

  9. Click here to start

    Indian Academy of Sciences (India)

    Click here to start. Table of contents. Slide 1 · Slide 2 · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Slide 8 · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Slide 15 · Slide 16 · Slide 17 · Slide 18 · Slide 19 · Slide 20.

  10. Getting started with Hazelcast

    CERN Document Server

    Johns, Mat

    2013-01-01

    Written as a step-by-step guide, Getting Started with Hazelcast will teach you all you need to know to make your application data scalable.This book is a great introduction for Java developers, software architects, or developers looking to enable scalable and agile data within their applications. You should have programming knowledge of Java and a general familiarity with concepts like data caching and clustering.

  11. Instant Start Thyratron Switch.

    Science.gov (United States)

    1981-01-01

    COVEHRID Intnt Start Thyratron SicInterim 1st & 2nd Triannual R pt Swich *1 September 1979 - 1 May 1980 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR( S OTAC...White Oak Laboratory Electronic Warfare Lab, ERADCOM ATTN: Library, Code WX-21 White Sand Missile Range, Silver Spring, MD 20910 NM 88002 010 Defense...Documentation Center 001 Defense Communications Agency ATTN: DDC-TCA Technical Library Center Cameron Station (Bldg 5) Code 205 (P.A. Tolovi) Alexandria

  12. Getting started with JUCE

    CERN Document Server

    Robinson, Martin

    2013-01-01

    his book is a fast-paced, practical guide full of step-by-step examples which are easy to follow and implement.This book is for programmers with a basic grasp of C++. The examples start at a basic level, making few assumptions beyond fundamental C++ concepts. Those without any experience with C++ should be able to follow and construct the examples, although you may need further support to understand the fundamental concepts.

  13. Getting started with Simulink

    CERN Document Server

    Zamboni, Luca

    2013-01-01

    This practical and easy-to-understand learning tutorial is one big exciting exercise for students and engineers that are always short on their schedules and want to regain some lost time with the help of Simulink.This book is aimed at students and engineers who need a quick start with Simulink. Though it's not required in order to understand how Simulink works, knowledge of physics will help the reader to understand the exercises described.

  14. International Mapping of Antenna-Measurement Facilities

    DEFF Research Database (Denmark)

    Boccia, Luigi; Breinbjerg, Olav; Di Massa, Giuseppe

    2006-01-01

    in the field of antenna measurements. It has been established to provide the scientific and industrial community with an efficient means to improve and facilitate their research and development activities in the field of antennas. The mapping will constitute a new service for all potential users of antenna...

  15. Future Vogues in Handset Antenna Systems

    DEFF Research Database (Denmark)

    Pelosi, Mauro; Pedersen, Gert Frølund

    2011-01-01

    This paper exemplifies future trends in handset antenna systems, contextualizing their historical evolution and anticipating novel paradigms. It is shown through numerical simulations how narrow-band antennas used in transceiver separation mode can reduce the total loss in presence of the user......’s hand, improving at the same time the antenna isolation....

  16. Numerical Study of Planar GPR Antenna Measurements

    DEFF Research Database (Denmark)

    Meincke, Peter; Hansen, Thorkild

    2004-01-01

    The formulation of planar near-field measurements of GPR antennas determines the plane-wave spectra of the GPR antenna in terms of measurements obtained with a buried probe as the GPR antenna moves over a scan plane on the ground. A numerical study investigates how the formulation is affected by (1...

  17. 47 CFR 74.641 - Antenna systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 74.641 Section 74.641... Stations § 74.641 Antenna systems. (a) For fixed stations operating above 2025 MHz, the following standards... elevation planes. (2) New periscope antenna systems will be authorized upon a certification that the...

  18. 47 CFR 78.105 - Antenna systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 78.105 Section 78.105... SERVICE Technical Regulations § 78.105 Antenna systems. (a) For fixed stations operating in the 12.7-13.2... planes. (2) New periscope antenna systems will be authorized upon a certification that the radiation, in...

  19. Orthogonal antenna architecture for MIMO handsets

    DEFF Research Database (Denmark)

    Tatomirescu, Alexandru; Alrabadi, Osama; Pedersen, Gert Frølund

    2012-01-01

    The paper presents a method for decorrelating the antenna elements of a MIMO system in a compact handheld terminal at low bands. The architecture of the antenna system induces orthogonal currents over the closely spaced antennas resulting in a correlation free system. Nevertheless, due to the small...

  20. Wireless link design using a patch antenna

    Energy Technology Data Exchange (ETDEWEB)

    Hall, E

    2000-08-11

    A wireless link was designed using a patch antenna. In the process, several different models were tested. Testing proved a patch antenna was a viable solution for building a wireless link within the design specifications. Also, this experimentation provided a basis for future patch antenna design.

  1. Antenna Construction and Propagation of Radio Waves.

    Science.gov (United States)

    Marine Corps Inst., Washington, DC.

    Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on antenna construction and propagation of radio waves is designed to provide communicators with instructions in the selection and/or construction of the proper antenna(s) for use with current field radio equipment. Introductory materials include…

  2. Start and the restriction point.

    Science.gov (United States)

    Johnson, Amy; Skotheim, Jan M

    2013-12-01

    Commitment to division requires that cells sense, interpret, and respond appropriately to multiple signals. In most eukaryotes, cells commit to division in G1 before DNA replication. Beyond a point, known as Start in yeast and the restriction point in mammals, cells will proceed through the cell cycle despite changes in upstream signals. In metazoans, misregulated G1 control can lead to developmental problems or disease, so it is important to understand how cells decipher the myriad external and internal signals that contribute to the fundamental all-or-none decision to divide. Extensive study of G1 control in the budding yeast Saccharomyces cerevisiae and mammalian culture systems has revealed highly similar networks regulating commitment. However, protein sequences of functional orthologs often indicate a total lack of conservation suggesting significant evolution of G1 control. Here, we review recent studies defining the conserved and diverged features of G1 control and highlight systems-level aspects that may be common to other biological regulatory networks. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Gravitational waves and antennas

    CERN Multimedia

    CERN. Geneva

    2003-01-01

    Gravitational waves and their detection represent today a hot topic, which promises to play a central role in astrophysics, cosmology and theoretical physics. Technological developments have enabled the construction of such sensitive detectors that the detection of gravitational radiation and the start of a new astronomy could become a reality during the next few years. This is expected to bring a revolution in our knowledge of the universe by allowing the observation of hiterto unseen phenomena such as coalescence of compact objects (neutron stars and black holes) fall of stars into supermassive black holes, stellar core collapses, big bang relics and the new and unexpected. In these lectures I give a brief overview of this challenging field of modern physics. Topics : Basic properties of gravitational radiation. Astrophysical sources. Principle of operation of detectors. Interferometers (both ground based and space-based), bars and spheres. Present status of the experiments, their recent results and their f...

  4. Installing the antenna for STELLA

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    The 3 metre diameter antenna for the STELLA satellite communication project is lowered into position on the roof of the Computer Building (see Weekly Bulletin 48/79 and CERN Courier 19 (1979) 444). STELLA stands for Satellite Transmission Experiment Linking Laboratories.

  5. The NOAA TOGA antenna array

    Science.gov (United States)

    Ecklund, W. L.; Carter, D. A.; Balsley, B. B.

    1986-01-01

    The Aeronomy Laboratory recently installed a 100 x 100 meter array antenna with limited beam steering on Christmas Island as a part of the TOGA (Tropical Ocean and Global Atmosphere) program. The array and the associated beam steering and indicating hardware are described.

  6. Photogrammetry Of A Parabolic Antenna

    Science.gov (United States)

    Merrick, W. D.; Lansing, F. L.; Stoller, F. W.; Lobb, V. B.

    1988-01-01

    Surface measured with accuracy better than 10 to the negative fifth power times diameter. Report describes use of advanced close-range photogrammetry to determine deviations of 34-m-diameter antenna main reflector and subreflector from nominal paraboloidal shapes. Measurements enable removal of linear offsets and angular misalignments of subreflector, with consequent increase of 4 percent in aperture efficiency.

  7. Getting started with Arduino

    CERN Document Server

    Banzi, Massimo

    2011-01-01

    Arduino is the open-source electronics prototyping platform that's taken the design and hobbyist world by storm. This thorough introduction, updated for Arduino 1.0, gives you lots of ideas for projects and helps you work with them right away. From getting organized to putting the final touches on your prototype, all the information you need is here! Inside, you'll learn about: Interaction design and physical computingThe Arduino hardware and software development environmentBasics of electricity and electronicsPrototyping on a solderless breadboardDrawing a schematic diagram Getting started

  8. Getting Started with Processing

    CERN Document Server

    Reas, Casey

    2010-01-01

    Learn computer programming the easy way with Processing, a simple language that lets you use code to create drawings, animation, and interactive graphics. Programming courses usually start with theory, but this book lets you jump right into creative and fun projects. It's ideal for anyone who wants to learn basic programming, and serves as a simple introduction to graphics for people with some programming skills. Written by the founders of Processing, this book takes you through the learning process one step at a time to help you grasp core programming concepts. You'll learn how to sketch wi

  9. Getting Started with Roo

    CERN Document Server

    Long, Josh

    2011-01-01

    Spring Roo goes a step beyond the Spring Framework by bringing true Rapid Application Development to Java-just as Grails has done with Groovy. This concise introduction shows you how to build applications with Roo, using the framework's shell as an intelligent and timesaving code-completion tool. It's an ideal RAD tool because Roo does much of the tedious code maintenance. You'll get started by building a simple customer relationship management application, complete with step-by-step instructions and code examples. Learn how to control any part of the application with Roo's opt-in feature, w

  10. En god start

    DEFF Research Database (Denmark)

    Sievertsen, Hans Henrik

    I Danmark er det muligt at afvige fra reglen om, at barnet skal starte i skole det kalenderår, hvor barnet fylder 6 år. Det gør 10-15 procent af en årgang, mens 80-90 procent af børnene følger normen, og 2-3 procent starter i skole et år tidligere end normen, viser en analyse baseret på børn født i...

  11. Antenna Miniaturization with MEMS Tunable Capacitors

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert Frølund

    2014-01-01

    In today’s mobile device market, there is a strong need for efficient antenna miniaturization. Tunable antennas are a very promising way to reduce antenna volume while enlarging its operating bandwidth. MEMS tunable capacitors are state-ofthe- art in terms of insertion loss...... and their characteristics are used in this investigation. This paper uses field simulations to highlight the trade-offs between the design of the tuner and the design of the antenna, especially the impact of the location of the tuner and the degree of miniaturization. Co-designing the tuner and the antenna is essential...

  12. Multi-antenna synthetic aperture radar

    CERN Document Server

    Wang, Wen-Qin

    2013-01-01

    Synthetic aperture radar (SAR) is a well-known remote sensing technique, but conventional single-antenna SAR is inherently limited by the minimum antenna area constraint. Although there are still technical issues to overcome, multi-antenna SAR offers many benefits, from improved system gain to increased degrees-of-freedom and system flexibility. Multi-Antenna Synthetic Aperture Radar explores the potential and challenges of using multi-antenna SAR in microwave remote sensing applications. These applications include high-resolution imaging, wide-swath remote sensing, ground moving target indica

  13. Forward Scattering of Loaded and Unloaded Antennas

    DEFF Research Database (Denmark)

    Gustafsson, Mats; Andersen, Jørgen Bach; Kristensson, Gerhard

    2012-01-01

    Forward scattering of antennas is related to antenna performance via the forward-scattering sum rule. The forward-scattering sum rule is an integral identity that shows that a weighted integral of the extinction cross section over all spectrum is proportional to the static polarizability...... of the antenna structure. Here, the forward-scattering sum rule is experimentally verified for loaded, short-circuit, and open-circuit cylindrical dipole antennas. It is also shown that the absorption efficiency cannot be greater than 1/2 for reciprocal linearly polarized lossless matched antennas...

  14. All printed antenna based on silver nanoparticles for 1.8 GHz applications

    Science.gov (United States)

    Hassan, Arshad; Ali, Shawkat; Bae, Jinho; Lee, Chong Hyun

    2016-08-01

    In this paper, we propose a novel printed antenna for 1.8 GHz band applications. The proposed antenna is made of silver nanoparticle-based radiating element and 0.04-mm thin, transparent and flexible polyethylene terephthalate (PET) substrate. The proposed antenna is designed and simulated by finite-element-method-based high-frequency structure simulator (HFSS). We obtain reflection coefficient of -23 dB, gain of 2.72 dBi and efficiency of 93.33 %. The resonance frequency of the antenna is also verified through national instrument (NI) Multisim simulation on the proposed equivalent circuit. We realize the antenna in a single process by commercial Dimatix material inkjet printer (DMP-3000) at ambient condition and characterize it by using vector network analyzer and spectrum analyzer. The measured reflection coefficient and -10 dB bandwidth are -32.2 dB and 190.5 MHz, respectively, which shows good agreement with HFSS and NI Multisim results. The proposed compact and optimum antenna printed on thin, transparent and fully bendable PET substrate becomes very attractive since it can overcome the limits of cost and size. These results suggest that the proposed antenna is well suitable for electronic devices operating over 1.8 GHz band such as Telos-B and other wearable printed devices.

  15. Microstrip Antenna for Remote Sensing of Soil Moisture and Sea Surface Salinity

    Science.gov (United States)

    Ramhat-Samii, Yahya; Kona, Keerti; Manteghi, Majid; Dinardo, Steven; Hunter, Don; Njoku, Eni; Wilson, Wiliam; Yueh, Simon

    2009-01-01

    This compact, lightweight, dual-frequency antenna feed developed for future soil moisture and sea surface salinity (SSS) missions can benefit future soil and ocean studies by lowering mass, volume, and cost of the antenna system. It also allows for airborne soil moisture and salinity remote sensors operating on small aircraft. While microstrip antenna technology has been developed for radio communications, it has yet to be applied to combined radar and radiometer for Earth remote sensing. The antenna feed provides a key instrument element enabling high-resolution radiometric observations with large, deployable antennas. The design is based on the microstrip stacked-patch array (MSPA) used to feed a large, lightweight, deployable, rotating mesh antenna for spaceborne L-band (approximately equal to 1 GHz) passive and active sensing systems. The array consists of stacked patches to provide dual-frequency capability and suitable radiation patterns. The stacked-patch microstrip element was designed to cover the required L-band center frequencies at 1.26 GHz (lower patch) and 1.413 GHz (upper patch), with dual-linear polarization capabilities. The dimension of patches produces the required frequencies. To achieve excellent polarization isolation and control of antenna sidelobes for the MSPA, the orientation of each stacked-patch element within the array is optimized to reduce the cross-polarization. A specialized feed-distribution network was designed to achieve the required excitation amplitude and phase for each stacked-patch element.

  16. Sub-Surface Microwave Imaging Using Four-Slot Vivaldi Antenna with Improved Directivity

    Science.gov (United States)

    Akhter, Zubair; Kumar, Pankaj; Akhtar, M. Jaleel

    2017-01-01

    The conventional tapered slot Vivaldi antenna is well known for its ultra-wide band characteristics with low directivity. To improve the directivity of the conventional Vivaldi antenna, a four-slot Vivaldi antenna (FSVA) is proposed here to operate in the frequency range of 2-11 GHz. For feeding the FSVA, a binomial three-section V-shaped even mode power divider with progressing T-junctions is also designed and tested here, which is then integrated with the antenna. The proposed antenna prototype is designed and fabricated on a 1-mm thick FR-4 substrate (ɛr=4.3, tanδ=0.025), and the return loss and radiation characteristics are investigated in the anechoic environment. The measured result shows a good agreement with the numerical simulation performed using the EM Simulator i. e. CST MWS-2015. It is found that the directivity of FSVA is approximately doubled as compared to that of the conventional Vivaldi antenna having the same dimensions. From the application point of view, the fabricated antenna is used to image various metallic objects hidden inside the sand using a vector network analyzer and associated RF components. The obtained 2D microwave images of the test media successfully show that the hidden objects can effectively be located and detected using the proposed FSVA in conjunction with a simple imaging scheme.

  17. An Orbital Angular Momentum (OAM) Mode Reconfigurable Antenna for Channel Capacity Improvement and Digital Data Encoding.

    Science.gov (United States)

    Liu, Baiyang; Lin, Guoying; Cui, Yuehui; Li, RongLin

    2017-08-29

    For purpose of utilizing orbital angular momentum (OAM) mode diversity, multiple OAM beams should be generated preferably by a single antenna. In this paper, an OAM mode reconfigurable antenna is proposed. Different from the existed OAM antennas with multiple ports for multiple OAM modes transmitting, the proposed antenna with only a single port, but it can be used to transmit mode 1 or mode -1 OAM beams arbitrary by controlling the PIN diodes on the feeding network through a programmable microcontroller which control by a remote controller. Simulation and measurement results such as return loss, near-field and far-field radiation patterns of two operating states for mode 1 and mode -1, and OAM mode orthogonality are given. The proposed antenna can serve as a candidate for utilizing OAM diversity, namely phase diversity to increase channel capacity at 2.4 GHz. Moreover, an OAM-mode based encoding method is experimentally carried out by the proposed OAM mode reconfigurable antenna, the digital data are encoded and decoded by different OAM modes. At the transmitter, the proposed OAM mode reconfigurable antenna is used to encode the digital data, data symbol 0 and 1 are mapped to OAM mode 1 and mode -1, respectively. At the receiver, the data symbols are decoded by phase gradient method.

  18. The design of RFID convey or belt gate systems using an antenna control unit.

    Science.gov (United States)

    Park, Chong Ryol; Lee, Seung Joon; Eom, Ki Hwan

    2011-01-01

    This paper proposes an efficient management system utilizing a Radio Frequency Identification (RFID) antenna control unit which is moving along with the path of boxes of materials on the conveyor belt by manipulating a motor. The proposed antenna control unit, which is driven by a motor and is located on top of the gate, has an array structure of two antennas with parallel connection. The array structure helps improve the directivity of antenna beam pattern and the readable RFID distance due to its configuration. In the experiments, as the control unit follows moving materials, the reading time has been improved by almost three-fold compared to an RFID system employing conventional fixed antennas. The proposed system also has a recognition rate of over 99% without additional antennas for detecting the sides of a box of materials. The recognition rate meets the conditions recommended by the Electronic Product Code glbal network (EPC)global for commercializing the system, with three antennas at a 20 dBm power of reader and a conveyor belt speed of 3.17 m/s. This will enable a host of new RFID conveyor belt gate systems with increased performance.

  19. Design Optimization and Trade-Offs of Miniaturized Wideband Antenna for Internet of Things Applications

    Directory of Open Access Journals (Sweden)

    ul Haq Muhammad Aziz

    2017-09-01

    Full Text Available Internet of Things (IoT will play an important role in modern communication systems. Thousands of devices will talk to each other at the same time. Clearly, smart and efficient hardware will play a vital role in the development of IoT. In this context, the importance of antennas increases due to them being essential parts of communication networks. For IoT applications, a small size with good matching and over a wide frequency range is preferred to ensure reduced size of communication devices. In this paper, we propose a structure and discuss design optimization of a wideband antenna for IoT applications. The antenna consists of a stepped-impedance feed line, a rectangular radiator and a ground plane. The objective is to minimize the antenna footprint by simultaneously adjusting all geometry parameters and to maintain the electrical characteristic of antenna at an acceptable level. The obtained design exhibits dimensions of only 3.7 mm × 11.8 mm and a footprint of 44 mm2, an omnidirectional radiation pattern, and an excellent pattern stability. The proposed antenna can be easily handled within compact communication devices. The simulation results are validated through measurements of the fabricated antenna prototype.

  20. Optical slot antenna and its application

    Science.gov (United States)

    Park, Yeonsang; Kim, Jineun; Roh, Young-Geun; Park, Q.-Han

    2017-02-01

    We present an optical slot antenna and its application. By measuring transmission spectra and far-field radiation pattern of metallic slots with nanometer scale, we show that a metallic nanoslot has the properties of an antenna, which are resonance, polarization, and bidirectional far-field radiation pattern, and can be regarded as a magnetic dipole in optical region. Additionally, we also make the unidirectional radiation by adapting the geometry of RF Yagi-Uda antenna and applying slot antenna. By the aid of phase analysis based on 3-dimensional finite-difference time-domain simulation, we can increase the front-to-back ratio of an optical slot Yagi-Uda antenna up to about 5. As the application of a slot antenna, we integrate a metal-insulator-metal plasmonic waveguide with a slot antenna. A surface plasmon waveguide mode propagating in MIM structure is well-coupled to a slot antenna and radiates into free-space in form of dipole radiation. By adding an auxiliary structure that has the role of reflector as like a slot Yagi-Uda antenna, the direction of radiation from a slot antenna integrated with a plasmonic waveguide can be controlled efficiently. Besides the possibility of integration with a waveguide, we expect that a slot antenna can be applied to active devices such as light emitting diodes or lasers for the future.

  1. Broad band antennas and feed methods

    Science.gov (United States)

    Benzel, David M.; Twogood, Richard E.

    2017-04-18

    Two or more Vivaldi antennas, consisting of two plates each, each with the antenna's natural impedance of approximately 100 ohms, are placed in parallel to achieve a 50 ohm impedance in the case of two antennas or other impedances (100/n ohms) for more than two antennas. A single Vivaldi antenna plate (half Vivaldi antenna) over a ground plane can also be used to achieve a 50 ohm impedance, or two or more single plates over a ground plane to achieve other impedances. Unbalanced 50 ohm transmission lines, e.g. coaxial cables, can be used to directly feed, the dual Vivaldi (four plate) antenna in a center fed angled center departure, or more desirably, a center fed offset departure configuration.

  2. Broad band antennas and feed methods

    Energy Technology Data Exchange (ETDEWEB)

    Benzel, David M.; Twogood, Richard E.

    2017-04-18

    Two or more Vivaldi antennas, consisting of two plates each, each with the antenna's natural impedance of approximately 100 ohms, are placed in parallel to achieve a 50 ohm impedance in the case of two antennas or other impedances (100/n ohms) for more than two antennas. A single Vivaldi antenna plate (half Vivaldi antenna) over a ground plane can also be used to achieve a 50 ohm impedance, or two or more single plates over a ground plane to achieve other impedances. Unbalanced 50 ohm transmission lines, e.g. coaxial cables, can be used to directly feed, the dual Vivaldi (four plate) antenna in a center fed angled center departure, or more desirably, a center fed offset departure configuration.

  3. Isolation between three antennas at 700 MHz

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Svendsen, Simon; Pedersen, Gert F.

    2015-01-01

    To address the antenna design challenges posed by many frequency bands, introduced with long-term evolution deployment, this study proposes the use of separate transmit (Tx) and receive (Rx) narrow-band antennas. In addition, a diversity Rx (Dx) antenna is needed for multiple-input multiple......-output performance. Although the isolation between two antennas at low frequencies (700 MHz) is crucial for the successful implementation of 4G in handheld terminals, it becomes more challenging when considering isolation among three antennas (one Tx and two Rx antennas) at low frequencies. Hence, a method...... that improves the isolation between the ports of one Tx and two Rx antennas is presented here. Publishe...

  4. A millimeter-wave connected antenna array for 5G applications

    KAUST Repository

    Ikram, Muhammad

    2017-10-25

    In this work, a beam switched antenna system based on a planar connected antenna array (CAA) is proposed at 28 GHz for 5G applications. The antenna system consists of a 4 × 4 connected slot antenna elements. It is covering frequency band from 27.4 GHz to 28.23 GHz with at least −10dB bandwidth of 830 MHz. It is modeled on a commercially available RO3003 substrate with ∊r equal to 3.3. The dimensions of the board are equal to 61×54×0.13 mm3. The proposed design is compact and low profile. A Butler matrix based feed network is used to steer the beam at different locations.

  5. Compact Dual-Band Planar Inverted-e-Shaped Antenna Using Defected Ground Structure

    Directory of Open Access Journals (Sweden)

    Wen Piao Lin

    2014-01-01

    Full Text Available This paper presents a novel dual-band planar inverted-e-shaped antenna (PIEA using defected ground structure (DGS for Bluetooth and wireless local area network (WLAN applications. The PIEA can reduce electromagnetic interferences (EMIs and it is constructed on a compact printed circuit board (PCB size of 10 × 5 × 4 mm3. Experimental results indicate that the antenna with a compact meandered slit can improve the operating impedance matching and bandwidths at 2.4 and 5.5 GHz. The measured power gains at 2.4 and 5.5 GHz band are 1.99 and 3.71 dBi; antenna efficiencies are about 49.33% and 55.23%, respectively. Finally, the good performances of the proposed antenna can highly promote for mobile device applications.

  6. Study of a Flexible Low Profile Tunable Dipole Antenna Using Barium Strontium Titanate Varactors

    Science.gov (United States)

    Cure, David; Weller, Thomas; Miranda, Felix A.

    2014-01-01

    In this paper a flexible low profile dipole antenna using a frequency selective surface (FSS) with interdigital barium strontium titanate (BST) varactor-tuned unit cells is presented. The varactor chips were placed only along one dimension of the FSS to avoid the use of vias and simplify the DC bias network. The antenna uses overlapping metallic plates that resemble fish scales as a ground plane to improve the flexibility of the multi-material stack structure. The measured data of the antenna demonstrate tunability from 2.42 GHz to 2.66 GHz and 1.3 dB gain drop when using overlapping metallic plates instead of continuous ground plane. The total antenna thickness is approximately lambda/24.

  7. Characterization of Miniature Millimeter-Wave Vivaldi Antenna for Local Multipoint Distribution Service

    Science.gov (United States)

    Simon, Rainee N.; Lee, Richard Q.

    1997-01-01

    The paper presents first, an efficient measurement technique to characterize the input impedance of a Vivaldi antenna, second, a simple technique to impedance match a Vivaldi antenna to a 50 Ohm feed line and lastly, a desktop arrangement to determine the directional gain of a Vivaldi antenna. The characterization is done using a microwave wafer probe station, a ground-signal microwave probe, impedance standard substrate and an automatic network analyzer. The Vivaldi antenna with a matching transformer has a VSVIR close to unity and a gain of about 10 dB over the frequency band of 27.5 to 28.35 GHz which is allocated for local multipoint distribution service (LMDS).

  8. The Healthy Start project

    DEFF Research Database (Denmark)

    Olsen, Nanna J; Buch-Andersen, Tine; Händel, Mina N

    2012-01-01

    , and to intervene not only by improving diet and physical activity, but also reduce stress and improve sleep quality and quantity. METHODS: Based on information from the Danish national birth registry and administrative birth forms, children were selected based on having either high birth weight, a mother who......-going, but it is estimated that 394 children will be included. The intervention took place over on average 11/2 year, between 2009 and 2011, and consisted of optional individual guidance in optimizing diet and physical activity habits, reducing chronic stress and stressful events and improving sleep quality and quantity....... The intervention also included participation in cooking classes and play arrangements. Information on dietary intake, meal habits, physical activity, sleep habits, and overall stress level was obtained by 4-7 day questionnaire dairies and objective measurements. DISCUSSION: If the Healthy Start project...

  9. RF Antenna Design for a Helicon Plasma Source

    Science.gov (United States)

    Godden, Katarina; Stassel, Brendan; Warta, Daniel; Yep, Isaac; Hicks, Nathaniel; Munk, Jens

    2017-10-01

    A helicon plasma source is under development for the new Plasma Science and Engineering Laboratory at the University of Alaska Anchorage. The helicon source is of a type comprising Pyrex and stainless steel cylindrical sections, joined to an ultrahigh vacuum chamber. A radio frequency (RF) helical antenna surrounds the Pyrex chamber, as well as DC solenoidal magnetic field coils. This presentation focuses on the design of the RF helical antenna and RF matching network, such that helicon wave power is coupled to argon plasma with minimal reflected power to the RF amplifier. The amplifier output is selectable between 2-30 MHz, with forward c.w. power up to 1.5 kW. Details and computer simulation of the antenna geometry, materials, and power matching will be presented, as well as the matching network of RF transmission line, tuning capacitors, and cooling system. An initial computational study of power coupling to the plasma will also be described. Supported by U.S. NSF/DOE Partnership in Basic Plasma Science and Engineering Grant PHY-1619615, by the Alaska Space Grant Program, and by UAA Innovate 2017.

  10. A Review on the Development of Rotman Lens Antenna

    Directory of Open Access Journals (Sweden)

    Shruti Vashist

    2014-01-01

    Full Text Available Rotman lenses are the beguiling devices used by the beamforming networks (BFNs. These lenses are generally used in the radar surveillance systems to see targets in multiple directions due to its multibeam capability without physically moving the antenna system. Now a days these lenses are being integrated into many radars and electronic warfare systems around the world. The antenna should be capable of producing multiple beams which can be steered without changing the orientation of the antenna. Microwave lenses are the one who support low-phase error, wideband, and wide-angle scanning. They are the true time delay (TTD devices producing frequency independent beam steering. The emerging printed lenses in recent years have facilitated the advancement of designing high performance but low-profile, light-weight, and small-size and networks (BFNs. This paper will review and analyze various design concepts used over the years to improve the scanning capability of the lens developed by various researchers.

  11. The Lean and Global Start-up

    DEFF Research Database (Denmark)

    Tanev, Stoyan; Rasmussen, Erik Stavnsager

    For several decades researchers have studied start-up companies with a focus on international markets, suppliers and networks from their inception and on companies that are establishing new, agile business models. This has resulted in two streams of research: The Born Global and International New...... Ventures research and research with a focus on the Lean Start-up company. It is our intention in this paper to give a short presentation of the two research streams and show how they can be merged into one with a focus on newly established technology oriented firms that are lean and global from...

  12. Radio pill antenna range test

    Science.gov (United States)

    Cummins, W. F.; Kane, R. J.

    1992-05-01

    In order to investigate the potential of a proposed 'radio pill' beacon transmitter, a range test experiment was devised and carried out in the VHF frequency range. Calculations and previous work indicated that optimum sensitivity and, thus, distance would be obtained in this frequency range provided body radio-frequency (RF) absorption was not too great. A ferrite-core loop antenna is compatible with a pill geometry and has better radiation efficiency than an air core loop. The ferrite core may be a hollow cylinder with the electronics and batteries placed inside. However, this range test was only concerned with experimentally developing test range data on the ferrite core antenna itself. A one turn strap loop was placed around a 9.5 mm diameter by 18.3 mm long stack of ferrite cores. This was coupled to a 50 Omega transmission line by 76 mm of twisted pair line and a capacitive matching section. This assembly was excited by a signal generator at output levels of -10 to +10 dBm. Signals were received on a VHF receiver and tape recorder coupled to a 14 element, circularly polarized Yagi antenna at a height of 2.5 m. Field strength measurements taken at ranges of 440, 1100, and 1714 m. Maximum field strengths referenced to 0 dBm transmitter level were -107 to -110 dB at 440 m, -124 to -127 dBm at 1100 m, and -116 to -119 dBm at 1714 m when the antenna cylinder was horizontal. Field strengths with a vertical antenna were about 6 dB below these values. The latter transmit site was elevated and had a clear line-of-site path to the receiving site. The performance of this test antenna was better than that expected from method-of-moment field calculations. When this performance data is scaled to a narrow bandwidth receiving system, ground level receiving ranges of a few to 10 km can be expected. Clear line-of-sight ranges where either or both the transmitter and receiver are elevated could vary from several km to 100 km.

  13. Performance of Adaptive Antennas in FH-GSM Using Conventional Beamforming

    DEFF Research Database (Denmark)

    Mogensen, Preben Elgaard; Leth-Espensen, P; Zetterberg, P.

    2000-01-01

    This paper presents the performance of adaptive antennas in a 1/3 reuse frequency hopping GSM network using conventional beamforming. It mainly focuses on C/I improvement for the purpose of capacity enhancement. The performance evaluation has been conducted by means of network computer simulations...... for low azimuth spread values. For large values of azimuth spread (relative to the antenna beamwidth), the performance gain is reduced significantly. For an azimuth spread of 10 degrees-12 degrees, which has been measured in urban macro-cellular environments, the C/I gain for M = 8 is reduced to approx. 5...

  14. Aligning a Receiving Antenna Array to Reduce Interference

    Science.gov (United States)

    Jongeling, Andre P.; Rogstad, David H.

    2009-01-01

    A digital signal-processing algorithm has been devised as a means of aligning (as defined below) the outputs of multiple receiving radio antennas in a large array for the purpose of receiving a desired weak signal transmitted by a single distant source in the presence of an interfering signal that (1) originates at another source lying within the antenna beam and (2) occupies a frequency band significantly wider than that of the desired signal. In the original intended application of the algorithm, the desired weak signal is a spacecraft telemetry signal, the antennas are spacecraft-tracking antennas in NASA s Deep Space Network, and the source of the wide-band interfering signal is typically a radio galaxy or a planet that lies along or near the line of sight to the spacecraft. The algorithm could also afford the ability to discriminate between desired narrow-band and nearby undesired wide-band sources in related applications that include satellite and terrestrial radio communications and radio astronomy. The development of the present algorithm involved modification of a prior algorithm called SUMPLE and a predecessor called SIMPLE. SUMPLE was described in Algorithm for Aligning an Array of Receiving Radio Antennas (NPO-40574), NASA Tech Briefs Vol. 30, No. 4 (April 2006), page 54. To recapitulate: As used here, aligning signifies adjusting the delays and phases of the outputs from the various antennas so that their relatively weak replicas of the desired signal can be added coherently to increase the signal-to-noise ratio (SNR) for improved reception, as though one had a single larger antenna. Prior to the development of SUMPLE, it was common practice to effect alignment by means of a process that involves correlation of signals in pairs. SIMPLE is an example of an algorithm that effects such a process. SUMPLE also involves correlations, but the correlations are not performed in pairs. Instead, in a partly iterative process, each signal is appropriately weighted

  15. Impact of different individual GNSS receiver antenna calibration models on geodetic positioning

    Science.gov (United States)

    Baire, Q.; Pottiaux, E.; Bruyninx, C.; Defraigne, P.; Aerts, W.; Legrand, J.; Bergeot, N.; Chevalier, J. M.

    2012-04-01

    Since April 2011, the igs08.atx antenna calibration model is used in the routine IGS (International GNSS Service) data analysis. The model includes mean robot calibrations to correct for the offset and phase center variations of the GNSS receiver antennas. These so-called "type" calibrations are means of the individual calibrations available for a specific antenna/radome combination. The GNSS data analysis performed within the EUREF Permanent Network (EPN) aims at being as consistent as possible with the IGS analysis. This also applies to the receiver antenna calibrations. However, when available, individual antenna calibrations are used within the EPN analysis instead of the "type" calibration. When these individual calibrations are unavailable, then the EPN analysis falls back to (type) calibrations identical as the ones used within the IGS (igs08.atx). The aim of this study is to evaluate the significance of the offset caused by using different receiver antenna calibration models on the station position. Using the PPP (Precise Point Positioning) technique, we first investigate the differences in positioning obtained when switching between individual antenna calibrations and type calibrations. We analyze the observations of the 43 EPN stations equipped with receiver antenna individually calibrated over the period covering from 2003 to 2010 and we show that these differences can reach up to 4 mm in horizontal and 10 mm in vertical. Secondly, we study the accuracy of the individual calibrations models and we evaluate the effect of different sets of individual calibrations on the positioning. For that purpose, we use the data from 6 GNSS stations equipped with an antenna which has been individually calibrated at two calibration facilities recognized by the IGS: GEO++ and Bonn institute.

  16. Design of shape memory alloy actuated intelligent parabolic antenna for space applications

    Science.gov (United States)

    Kalra, Sahil; Bhattacharya, Bishakh; Munjal, B. S.

    2017-09-01

    The deployment of large flexible antennas is becoming critical for space applications today. Such antenna systems can be reconfigured in space for variable antenna footprint, and hence can be utilized for signal transmission to different geographic locations. Due to quasi-static shape change requirements, coupled with the demand of large deflection, shape memory alloy (SMA) based actuators are uniquely suitable for this system. In this paper, we discuss the design and development of a reconfigurable parabolic antenna structure. The reflector skin of the antenna is vacuum formed using a metalized polycarbonate shell. Two different strategies are chosen for the antenna actuation. Initially, an SMA wire based offset network is formed on the back side of the reflector. A computational model is developed using equivalent coefficient of thermal expansion (ECTE) for the SMA wire. Subsequently, the interaction between the antenna and SMA wire is modeled as a constrained recovery system, using a 1D modified Brinson model. Joule effect based SMA phase transformation is considered for the relationship between input voltage and temperature at the SMA wire. The antenna is modeled using ABAQUS based finite element methodology. The deflection found through the computational model is compared with that measured in experiment. Subsequently, a point-wise actuation system is developed for higher deflection. For power-minimization, an auto-locking device is developed. The performance of the new configuration is compared with the offset-network configuration. It is envisaged that the study will provide a comprehensive procedure for the design of intelligent flexible structures especially suitable for space applications.

  17. Phased-array-fed antenna configuration study, volume 2

    Science.gov (United States)

    Sorbello, R. M.; Zaghloul, A. I.; Lee, B. S.; Siddiqi, S.; Geller, B. D.

    1983-01-01

    Increased capacity in future satellite systems can be achieved through antenna systems which provide multiplicity of frequency reuses at K sub a band. A number of antenna configurations which can provide multiple fixed spot beams and multiple independent spot scanning beams at 20 GHz are addressed. Each design incorporates a phased array with distributed MMIC amplifiers and phasesifters feeding a two reflector optical system. The tradeoffs required for the design of these systems and the corresponding performances are presented. Five final designs are studied. In so doing, a type of MMIC/waveguide transition is described, and measured results of the breadboard model are presented. Other hardware components developed are described. This includes a square orthomode transducer, a subarray fed with a beamforming network to measure scanning performance, and another subarray used to study mutual coupling considerations. Discussions of the advantages and disadvantages of the final design are included.

  18. Omnidirectional antenna having constant phase

    Energy Technology Data Exchange (ETDEWEB)

    Sena, Matthew

    2017-04-04

    Various technologies presented herein relate to constructing and/or operating an antenna having an omnidirectional electrical field of constant phase. The antenna comprises an upper plate made up of multiple conductive rings, a lower ground-plane plate, a plurality of grounding posts, a conical feed, and a radio frequency (RF) feed connector. The upper plate has a multi-ring configuration comprising a large outer ring and several smaller rings of equal size located within the outer ring. The large outer ring and the four smaller rings have the same cross-section. The grounding posts ground the upper plate to the lower plate while maintaining a required spacing/parallelism therebetween.

  19. Distributed antenna system and method

    Science.gov (United States)

    Fink, Patrick W. (Inventor); Dobbins, Justin A. (Inventor)

    2004-01-01

    System and methods are disclosed for employing one or more radiators having non-unique phase centers mounted to a body with respect to a plurality of transmitters to determine location characteristics of the body such as the position and/or attitude of the body. The one or more radiators may consist of a single, continuous element or of two or more discrete radiation elements whose received signals are combined. In a preferred embodiment, the location characteristics are determined using carrier phase measurements whereby phase center information may be determined or estimated. A distributed antenna having a wide angle view may be mounted to a moveable body in accord with the present invention. The distributed antenna may be utilized for maintaining signal contact with multiple spaced apart transmitters, such as a GPS constellation, as the body rotates without the need for RF switches to thereby provide continuous attitude and position determination of the body.

  20. Plasmonic Antenna Coupling for QWIPs

    Science.gov (United States)

    Hong, John

    2007-01-01

    In a proposed scheme for coupling light into a quantum-well infrared photodetector (QWIP), an antenna or an array of antennas made of a suitable metal would be fabricated on the face of what would otherwise be a standard QWIP. This or any such coupling scheme is required to effect polarization conversion: Light incident perpendicularly to the face is necessarily polarized in the plane of the face, whereas, as a matter of fundamental electrodynamics and related quantum selection rules, light must have a non-zero component of perpendicular polarization in order to be absorbed in the photodetection process. In a prior coupling scheme, gratings in the form of surface corrugations diffract normally gles, thereby imparting some perpendicular polarization. Unfortunately, the corrugation- fabrication process increases the overall nonuniformity of a large QWIP array. The proposed scheme is an alternative to the use of surface corrugations.

  1. Antenna Arrays and Automotive Applications

    CERN Document Server

    Rabinovich, Victor

    2013-01-01

    This book throws a lifeline to designers wading through mounds of antenna array patents looking for the most suitable systems for their projects. Drastically reducing the research time required to locate solutions to the latest challenges in automotive communications, it sorts and systematizes material on cutting-edge antenna arrays that feature multi-element communication systems with enormous potential for the automotive industry. These new systems promise to make driving safer and more efficient, opening up myriad applications, including vehicle-to-vehicle traffic that prevents collisions, automatic toll collection, vehicle location and fine-tuning for cruise control systems. This book’s exhaustive coverage begins with currently deployed systems, frequency ranges and key parameters. It proceeds to examine system geometry, analog and digital beam steering technology (including "smart" beams formed in noisy environments), maximizing signal-to-noise ratios, miniaturization, and base station technology that ...

  2. On the Effectiveness of a Z element for Enhancement of Matching, Gain and Reactive Near Fields of a Small Antenna

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Bonev, Ivan Bonev

    2010-01-01

    In this paper, an electrically small antenna with a parasitic Z-shaped element is presented. Compared to the previously proposed design, it has been proved that even if the Z element is disconnected from the ground plane, it still works as a natural matching network for the antenna. Two designs f...... decrease of the radiation toward the hand. Moreover, for the antenna with the Z element, the reduction in the magnetic RNF at distance 15 mm is almost 2 dB A/m compared to the antenna itself....... for two different frequency bands have been presented. The natural matching property has been demonstrated for an antenna working at 5.11 GHz and then another design tuned to 2.45 GHz has been investigated. The gain and the Reactive Near Fields (RNF) of the second design is studied, showing a high...

  3. Dual Mode Slotted Monopole Antenna

    Science.gov (United States)

    2017-01-05

    of 15 DUAL MODE SLOTTED MONOPOLE ANTENNA STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and used by...REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention is directed...such as this that is capable of radiating at a different frequency below this cutoff. The present invention provides a means by which the overall

  4. DSS 13 Microprocessor Antenna Controller

    Science.gov (United States)

    Gosline, R. M.

    1984-01-01

    A microprocessor based antenna controller system developed as part of the unattended station project for DSS 13 is described. Both the hardware and software top level designs are presented and the major problems encounted are discussed. Developments useful to related projects include a JPL standard 15 line interface using a single board computer, a general purpose parser, a fast floating point to ASCII conversion technique, and experience gained in using off board floating point processors with the 8080 CPU.

  5. Genetic Optimization of Wire Antennas

    Directory of Open Access Journals (Sweden)

    Z. Raida

    1998-09-01

    Full Text Available The presented submission describes how genetic algorithms can be applied to the optimization and design of wire antennas. The proposed optimization method is easily programmable and well understandable on one hand, but relatively slowly converging and depending on the parameters of the genetic algorithms on the other hand. The disadvantages of the method are deeply discussed and their elimination is discussed in the paper.

  6. LEP dismantling starts

    CERN Multimedia

    2000-01-01

    Since the end of November, various teams have been getting stuck into dismantling the LEP accelerator and its four experiments. After making the installations safe, the dismantling and removal of 40,000 tonnes of equipment is underway. Down in the tunnel, it is a solemn moment. It is 10 o'clock on 13 December and Daniel Regin, one of those heading the dismantling work, moves in on a magnet, armed with a hydraulic machine. Surrounded by teams gathered there for a course in dismantling, he makes the first cut into LEP. The great deconstruction has begun. In little over than a year, the accelerator will have been cleared away to make room for its successor, the LHC. The start of the operation goes back to 27 November. Because before setting about the machine with hydraulic shears and monkey wrenches, LEP had first to be made safe - it was important to make sure the machine could be taken apart without risk. All the SPS beam injection systems to LEP were cut off. The fluids used for cooling the magnets and superc...

  7. Starting physiology: bioelectrogenesis.

    Science.gov (United States)

    Baptista, Vander

    2015-12-01

    From a Cartesian perspective of rational analysis, the electric potential difference across the cell membrane is one of the fundamental concepts for the study of physiology. Unfortunately, undergraduate students often struggle to understand the genesis of this energy gradient, which makes the teaching activity a hard task for the instructor. The topic of bioelectrogenesis encompasses multidisciplinary concepts, involves several mechanisms, and is a dynamic process, i.e., it never turns off during the lifetime of the cell. Therefore, to improve the transmission and acquisition of knowledge in this field, I present an alternative didactic model. The design of the model assumes that it is possible to build, in a series of sequential steps, an assembly of proteins within the membrane of an isolated cell in a simulated electrophysiology experiment. Initially, no proteins are inserted in the membrane and the cell is at a baseline energy state; the extracellular and intracellular fluids are at thermodynamic equilibrium. Students are guided through a sequence of four steps that add key membrane transport proteins to the model cell. The model is simple at the start and becomes progressively more complex, finally producing transmembrane chemical and electrical gradients. I believe that this didactic approach helps instructors with a more efficient tool for the teaching of the mechanisms of resting membrane potential while helping students avoid common difficulties that may be encountered when learning this topic. Copyright © 2015 The American Physiological Society.

  8. An impressive start

    CERN Multimedia

    2011-01-01

    This has been an excellent week for the LHC, with a succession of fills rapidly increasing the number of proton bunches to 194 per beam. This has allowed the experiments to reach a peak luminosity of 2.5 × 1032 cm-2s-1, thereby surpassing the record for 2010 where we reached 2.0 × 1032 cm-2s-1. At the time of writing, the integrated luminosity delivered by the LHC in 2011 is around 28 inverse picobarns, which is already more than half of the total 2010 dataset.   These are impressive numbers, but what impresses me most is how quickly the LHC operators are now able to turn the machine around between fills, and how well LHC running has been incorporated into the overall operation of CERN’s accelerator complex. The flexibility of the LHC was illustrated on Thursday when we started a short phase of running at 1.38 TeV per beam, equivalent to the energy-per-nucleon of a lead-ion run. This lower energy data will be used by the experiments, in particular by ALICE, to compare...

  9. ATLAS starts moving in

    CERN Multimedia

    Della Mussia, S

    2004-01-01

    The first large active detector component was lowered into the ATLAS cavern on 1st March. It consisted of the 8 modules forming the lower part of the central barrel of the tile hadronic calorimeter. The work of assembling the barrel, which comprises 64 modules, started the following day. Two road trailers each with 64 wheels, positioned side by side. This was the solution chosen to transport the lower part of the central barrel of ATLAS' tile hadronic calorimeter from Building 185 to the PX16 shaft at Point 1 (see Figure 1). The transportation, and then the installation of the component in the experimental cavern, which took place over three days were, to say the least, rather spectacular. On 25 February, the component, consisting of eight 6-metre modules, was loaded on to the trailers. The segment of the barrel was transported on a steel support so that it wouldn't move an inch during the journey. On 26 February, once all the necessary safety checks had been carried out, the convoy was able to leave Buildi...

  10. Membrane Shell Reflector Segment Antenna

    Science.gov (United States)

    Fang, Houfei; Im, Eastwood; Lin, John; Moore, James

    2012-01-01

    The mesh reflector is the only type of large, in-space deployable antenna that has successfully flown in space. However, state-of-the-art large deployable mesh antenna systems are RF-frequency-limited by both global shape accuracy and local surface quality. The limitations of mesh reflectors stem from two factors. First, at higher frequencies, the porosity and surface roughness of the mesh results in loss and scattering of the signal. Second, the mesh material does not have any bending stiffness and thus cannot be formed into true parabolic (or other desired) shapes. To advance the deployable reflector technology at high RF frequencies from the current state-of-the-art, significant improvements need to be made in three major aspects: a high-stability and highprecision deployable truss; a continuously curved RF reflecting surface (the function of the surface as well as its first derivative are both continuous); and the RF reflecting surface should be made of a continuous material. To meet these three requirements, the Membrane Shell Reflector Segment (MSRS) antenna was developed.

  11. Curved spiral antennas for underwater biological applications

    Science.gov (United States)

    Llamas, Ruben

    We developed curved spiral antennas for use in underwater (freshwater) communications. Specifically, these antennas will be integrated in so-called mussel backpacks. Backpacks are compact electronics that incorporate sensors and a small radio that operate around 300 MHz. Researchers attach these backpacks in their freshwater mussel related research. The antennas must be small, lightweight, and form-fit the mussel. Additionally, since the mussel orientation is unknown, the antennas must have broad radiation patterns. Further, the electromagnetic environment changes significantly as the mussels burrow into the river bottom. Broadband antennas, such a spiral antennas, will perform better in this instance. While spiral antennas are well established, there has been little work on their performance in freshwater. Additionally, there has been some work on curved spiral antennas, but this work focused on curving in one dimension, namely curving around a cylinder. In this thesis we develop spiral antennas that curve in two dimensions in order to conform the contour of a mussel's shell. Our research has three components, namely (a) an investigation of the relevant theoretical underpinning of spiral antennas, (b) extensive computer simulations using state-of-the art computational electromagnetics (CEM) simulation software, and (c) experimental validation. The experimental validation was performed in a large tank in a laboratory setting. We also validated some designs in a pool (~300,000 liters of water and ~410 squared-meter dive pool) with the aid of a certified diver. To use CEM software and perform successful antenna-related experiments require careful attention to many details. The mathematical description of radiation from an antenna, antenna input impedance and so on, is inherently complex. Engineers often make simplifying assumptions such as assuming no reflections, or an isotropic propagation environment, or operation in the antenna far field, and so on. This makes

  12. A multi octaves directive dielectric lens: The Pyramid Antenna

    NARCIS (Netherlands)

    Marliani, L.; Bruni, S.; Neto, A.

    2005-01-01

    Leaky wave antennas have been investigated for a long time and are typically an inexpensive solution for beam scanning antennas. We have designed a novel antenna topology, named the pyramid antenna, based on the broadband leaky concept. The pyramid antenna, currently covered by a patent application,

  13. From Head Start to Sure Start: Reflections on Policy Transfer

    Science.gov (United States)

    Welshman, John

    2010-01-01

    This article uses the history of debates over the US Head Start programme (1965), Early Head Start (1994) and the UK Sure Start initiative (1998), as a window on to policy transfer. In all the three, the aim was that early intervention could offer a means of boosting children's educational attainment and of countering the wider effects of poverty…

  14. Modeling and Analysis of Cellular Networks using Stochastic Geometry: A Tutorial

    KAUST Repository

    Elsawy, Hesham

    2016-11-03

    This paper presents a tutorial on stochastic geometry (SG) based analysis for cellular networks. This tutorial is distinguished by its depth with respect to wireless communication details and its focus on cellular networks. The paper starts by modeling and analyzing the baseband interference in a baseline single-tier downlink cellular network with single antenna base stations and universal frequency reuse. Then, it characterizes signal-to-interference-plus-noise-ratio (SINR) and its related performance metrics. In particular, a unified approach to conduct error probability, outage probability, and transmission rate analysis is presented. Although the main focus of the paper is on cellular networks, the presented unified approach applies for other types of wireless networks that impose interference protection around receivers. The paper then extends the unified approach to capture cellular network characteristics (e.g., frequency reuse, multiple antenna, power control, etc.). It also presents numerical examples associated with demonstrations and discussions. To this end, the paper highlights the state-of-the- art research and points out future research directions.

  15. Metamaterial Embedded Wearable Rectangular Microstrip Patch Antenna

    Directory of Open Access Journals (Sweden)

    J. G. Joshi

    2012-01-01

    Full Text Available This paper presents an indigenous low-cost metamaterial embedded wearable rectangular microstrip patch antenna using polyester substrate for IEEE 802.11a WLAN applications. The proposed antenna resonates at 5.10 GHz with a bandwidth and gain of 97 MHz and 4.92 dBi, respectively. The electrical size of this antenna is 0.254λ×0.5λ. The slots are cut in rectangular patch to reduce the bending effect. This leads to mismatch the impedance at WLAN frequency band; hence, a metamaterial square SRR is embedded inside the slot. A prototype antenna has been fabricated and tested, and the measured results are presented in this paper. The simulated and measured results of the proposed antenna are found to be in good agreement. The bending effect on the performance of this antenna is experimentally verified.

  16. Millimeter-wave antennas configurations and applications

    CERN Document Server

    du Preez, Jaco

    2016-01-01

    This book comprehensively reviews the state of the art in millimeter-wave antennas, traces important recent developments and provides information on a wide range of antenna configurations and applications. While fundamental theoretical aspects are discussed whenever necessary, the book primarily focuses on design principles and concepts, manufacture, measurement techniques, and practical results. Each of the various antenna types scalable to millimeter-wave dimensions is considered individually, with coverage of leaky-wave and surface-wave antennas, printed antennas, integrated antennas, and reflector and lens systems. The final two chapters address the subject from a systems perspective, providing an overview of supporting circuitry and examining in detail diverse millimeter-wave applications, including high-speed wireless communications, radio astronomy, and radar. The vast amount of information now available on millimeter-wave systems can be daunting for researchers and designers entering the field. This b...

  17. Compact Miniaturized Antenna for 210 MHz RFID

    Science.gov (United States)

    Lee, Richard Q.; Chun, Kue

    2008-01-01

    This paper describes the design and simulation of a miniaturized square-ring antenna. The miniaturized antenna, with overall dimensions of approximately one tenth of a wavelength (0.1 ), was designed to operate at around 210 MHz, and was intended for radio-frequency identification (RFID) application. One unique feature of the design is the use of a parasitic element to improve the performance and impedance matching of the antenna. The use of parasitic elements to enhance the gain and bandwidth of patch antennas has been demonstrated and reported in the literature, but such use has never been applied to miniaturized antennas. In this work, we will present simulation results and discuss design parameters and their impact on the antenna performance.

  18. Mobile satellite communications - Vehicle antenna technology update

    Science.gov (United States)

    Bell, D.; Naderi, F. M.

    1986-01-01

    This paper discusses options for vehicle antennas to be used in mobile satellite communications systems. Two types of antennas are identified. A non-steerable, azimuthally omnidirectional antenna with a modest gain of 3 to 5 dBi is suggested when a low cost is desired. Alternatively, mechanically or electronically steerable antennas with a higher gain of 10 to 12 dBi are suggested to alleviate power and spectrum scarcity associated with mobile satellite communications. For steerable antennas, both open-loop and closed-loop pointing schemes are discussed. Monopulse and sequential lobing are proposed for the mechanically steered and electronically steered antennas, respectively. This paper suggests a hybrid open-loop/closed-loop pointing technique as the best performer in the mobile satellite environment.

  19. A Review of Antennas for Picosatellite Applications

    Directory of Open Access Journals (Sweden)

    Abdul Halim Lokman

    2017-01-01

    Full Text Available Cube Satellite (CubeSat technology is an attractive emerging alternative to conventional satellites in radio astronomy, earth observation, weather forecasting, space research, and communications. Its size, however, poses a more challenging restriction on the circuitry and components as they are expected to be closely spaced and very power efficient. One of the main components that will require careful design for CubeSats is their antennas, as they are needed to be lightweight, small in size, and compact or deployable for larger antennas. This paper presents a review of antennas suitable for picosatellite applications. An overview of the applications of picosatellites will first be explained, prior to a discussion on their antenna requirements. Material and antenna topologies which have been used will be subsequently discussed prior to the presentation of several deployable configurations. Finally, a perspective and future research work on CubeSat antennas will be discussed in the conclusion.

  20. Numerical Modeling of Ultra Wideband Combined Antennas

    Science.gov (United States)

    Zorkal'tseva, M. Yu.; Koshelev, V. I.; Petkun, A. A.

    2017-12-01

    With the help of a program we developed, based on the finite difference method in the time domain, we have investigated the characteristics of ultra wideband combined antennas in detail. The antennas were developed to radiate bipolar pulses with durations in the range 0.5-3 ns. Data obtained by numerical modeling are compared with the data of experimental studies on antennas and have been used in the synthesis of electromagnetic pulses with maximum field strength.

  1. NLO Antenna Subtraction with Massive Fermions

    OpenAIRE

    Ridder, A. Gehrmann-De; Ritzmann, M.

    2009-01-01

    We present an extension of the antenna subtraction formalism at NLO to include massive final state fermions. The basic ingredients to the subtraction terms, the NLO massive final-final antenna functions are derived and integrated over the corresponding factorised phase space. Those antenna functions account for all soft, collinear and quasi-collinear limits of the QCD matrix elements involving massive fermions in the final state.

  2. Quadric Resistive Sheet Profile for Wideband Antennas

    Directory of Open Access Journals (Sweden)

    Z. Raida

    2007-09-01

    Full Text Available A new type of a nonreflecting resistive dipole antenna with quadric continuous resistivity profile is presented in this paper. The antenna is mathematically described and compared with the antenna originally proposed by Wu and King. The verification of a proposed theory and the comparison between Wu-King and quadric profile are carried out by simulation models that were designed for this purpose. The attention is turned to the proper attenuation of a wave excited on the resistive sheet, especially.

  3. Spherical near-field antenna measurements — The most accurate antenna measurement technique

    DEFF Research Database (Denmark)

    Breinbjerg, Olav

    2016-01-01

    The spherical near-field antenna measurement technique combines several advantages and generally constitutes the most accurate technique for experimental characterization of radiation from antennas. This paper/presentation discusses these advantages, briefly reviews the early history and present...... status, and addresses future challenges for spherical near-field antenna measurements; in particular, from the viewpoint of the DTU-ESA Spherical Near-Field Antenna Test Facility....

  4. Near Field HF Antenna Pattern Measurement Method Using an Antenna Pattern Range

    Science.gov (United States)

    2015-12-01

    TECHNICAL REPORT 3006 December 2015 Near-Field HF Antenna Pattern Measurement Method Using an Antenna Pattern Range Ani Siripuram Michael Daly...link budget. This report focuses on computing absolute gain for HF antennas measured on the APR. Recent research efforts by SSC Pacific’s Applied...Electromagnetics Branch (Code 52250) show that the APR extends to accurate measurement of normalized far-field radiation patterns of HF antennas. The

  5. Energy efficient design for MIMO two-way AF multiple relay networks

    KAUST Repository

    Alsharoa, Ahmad M.

    2014-04-01

    This paper studies the energy efficient transmission and the power allocation problem for multiple two-way relay networks equipped with multi-input multi-output antennas where each relay employs an amplify-and-forward strategy. The goal is to minimize the total power consumption without degrading the quality of service of the terminals. In our analysis, we start by deriving closed-form expressions of the optimal powers allocated to terminals. We then employ a strong optimization tool based on the particle swarm optimization technique to find the optimal power allocated at each relay antenna. Our numerical results illustrate the performance of the proposed scheme and show that it achieves a sub-optimal solution very close to the optimal one.

  6. A Design of Double Broadband MIMO Antenna

    Directory of Open Access Journals (Sweden)

    Yanfeng Geng

    2015-01-01

    Full Text Available The MIMO antenna applied to LTE mobile system should be miniaturization and can work in the current communication frequency band; isolation between each antenna unit also should be good so as to reduce loss of radio wave energy and improve the antenna performance of the MIMO system. This paper puts forward the design scheme of a broadband MIMO double antenna. And the design of antenna unit and debugging and related technical measures, such as bending antenna bracket, are both presented; the integration design of high isolation of ultra broadband MIMO antenna is realized on the plate with the volume of 100 × 52 × 0.8 mm3; antenna working bands are 698 MHz~960 MHz and 1710 MHz~2700 MHz; in the whole spectrum, the 10 dB of port isolation can be basically achieved; in low frequency band, the isolation degree of antenna port can reach 12 dB.

  7. Antenna Showers with Hadronic Initial States

    CERN Document Server

    Ritzmann, M; Skands, P

    2013-01-01

    We present an antenna shower formalism including contributions from initial-state partons and corresponding backwards evolution. We give a set of phase-space maps and antenna functions for massless partons which define a complete shower formalism suitable for computing observables with hadronic initial states. We focus on the initial-state components: initial-initial and initial-final antenna configurations. The formalism includes comprehensive possibilities for uncertainty estimates. We report on some preliminary results obtained with an implementation in the Vincia antenna-shower framework.

  8. Three-dimensional winged nanocone optical antennas.

    Science.gov (United States)

    Huttunen, Mikko J; Lindfors, Klas; Andriano, Domenico; Mäkitalo, Jouni; Bautista, Godofredo; Lippitz, Markus; Kauranen, Martti

    2014-06-15

    We introduce 3D optical antennas based on winged nanocones. The antennas support particle plasmon oscillations with current distributions that facilitate transformation of transverse far-field radiation to strong longitudinal local fields near the cone apices. We characterize the optical responses of the antennas by their extinction spectra and by second-harmonic generation microscopy with cylindrical vector beams. The results demonstrate a new 3D polarization-controllable optical antenna for applications in apertureless near-field microscopy, spectroscopy, and plasmonic sensing.

  9. Broadband slant linearly polarized biconical antenna

    Science.gov (United States)

    Lakshminarayana, D.; Prasad, R. V. H.; Murthy, T. G. K.

    1993-06-01

    A broadband biconical antenna with a slant linear polarizer, operating over 2-26 GHz range was designed and fabricated. The results of tests are presented, including the return loss plot of the antenna, radiation patterns at 2, 10, and 26 GHz for vertical and horizontal polarizations in azimuth and elevation planes, and curves indicating the elevation beam-width and gain of the antenna vs. frequency. The antenna gives an omni deviation of +/- 3 dB over 2-26 GHz. It is highly compact, and thus is suitable for systems where space requirements are very stringent.

  10. Vivaldi Antenna for RF Energy Harvesting

    Directory of Open Access Journals (Sweden)

    J. Schneider

    2016-12-01

    Full Text Available Energy harvesting is a future technology for capturing ambient energy from the environment to be recycled to feed low-power devices. A planar antipodal Vivaldi antenna is presented for gathering energy from GSM, WLAN, UMTS and related applications. The designed antenna has the potential to be used in energy harvesting systems. Moreover, the antenna is suitable for UWB applications, because it operates according to FCC regulations (3.1 – 10.6 GHz. The designed antenna is printed on ARLON 600 substrate and operates in frequency band from 0.810 GHz up to more than 12 GHz. Experimental results show good conformity with simulated performance.

  11. Design of reconfigurable antennas using graph models

    CERN Document Server

    Costantine, Joseph; Christodoulou, Christos G; Christodoulou, Christos G

    2013-01-01

    This lecture discusses the use of graph models to represent reconfigurable antennas. The rise of antennas that adapt to their environment and change their operation based on the user's request hasn't been met with clear design guidelines. There is a need to propose some rules for the optimization of any reconfigurable antenna design and performance. Since reconfigurable antennas are seen as a collection of self-organizing parts, graph models can be introduced to relate each possible topology to a corresponding electromagnetic performance in terms of achieving a characteristic frequency of oper

  12. Antenna technology for advanced mobile communication systems

    Science.gov (United States)

    Rammos, Emmanuel; Roederer, Antoine; Rogard, Roger

    1988-01-01

    The onboard antenna front end is the key subsystem conditioning configuration and performance of mobile communication satellites. The objectives of this paper are to demonstrate this key role and to review L-band satellite antenna technology for earth coverage and regional applications. Multibeam arrays are first discussed, then unfurlable and inflatable reflector antennas are described. These technologies are now qualified in Europe for future mobile systems, for which the optimum choice of antenna technology has been found to be the key to efficient use of spectrum and power resources.

  13. Vertical Meandering Approach for Antenna Size Reduction

    Directory of Open Access Journals (Sweden)

    Li Deng

    2012-01-01

    Full Text Available A novel vertical meandering technique to reduce the lateral size of a planar printed antenna is presented. It is implemented by dividing a conventional spiral patch into a different number of segments and placing them on different sides of the microwave substrate with vias as the connections. To confirm the validity of this technique, measured electrical performance and radiation characteristics of five antennas with different numbers of segments are compared. The smallest antenna is reduced in size by 84% when compared with the conventional printed spiral antenna.

  14. Printed-Circuit Cross-Slot Antenna

    Science.gov (United States)

    Foy, Wong; Chung, Hsien-Hsien; Peng, Sheng Y.

    1990-01-01

    Coupling between perpendicular slots suppressed. Balanced feed configuration minimizes coupling between slots of printed-circuit cross-slot antenna unit. Unit and array have conventional cavity-backed-printed-circuit, crossed-slot antenna design. Strip-line feeders behind planar conductive antenna element deliver power to horizontal slot in opposite phase. As result, little or no power propagates into vertical slot. Similar considerations apply to strip lines that feed vertical slot. Units of this type elements of phased-array antennas for radar, mobile/satellite communications, and other applications requiring flush mounting and/or rapid steering of beams with circular polarization.

  15. Considerations for millimeter wave printed antennas

    Science.gov (United States)

    Pozar, D. M.

    1983-01-01

    Calculated data are presented on the performance of printed antenna elements on substrates which may be electrically thick, as would be the case for printed antennas at millimeter wave frequencies. Printed dipoles and microstrip patch antennas on polytetrafluoroethylene (PTFE), quartz, and gallium arsenide substrates are considered. Data are given for resonant length, resonant resistance, bandwidth, loss due to surface waves, loss due to dielectric heating, and mutual coupling. Also presented is an optimization procedure for maximizing or minimizing power launched into surface waves from a multielement printed antenna array. The data are calculated by a moment method solution.

  16. Handbook of smart antennas for RFID systems

    CERN Document Server

    2010-01-01

    The Handbook of Smart Antennas for RFID Systems is a single comprehensive reference on the smart antenna technologies applied to RFID. This book will provide a timely reference book for researchers and students in the areas of both smart antennas and RFID technologies. It is the first book to combine two of the most important wireless technologies together in one book. The handbook will feature chapters by leading experts in both academia and industry offering an in-depth description of terminologies and concepts related to smart antennas in various RFID systems applications.

  17. A SIW Antipodal Vivaldi Array Antenna Design

    Directory of Open Access Journals (Sweden)

    Ying Suo

    2016-01-01

    Full Text Available A kind of compact SIW (substrate integrated waveguide Vivaldi array antenna is proposed and analyzed. The antenna consisted of 4 Vivaldi structure radiation elements fed by an equal power divider with SIW technology. The radiation element is composed of antipodal index gradient microstrip lines on both sides of the substrate. The measured reflection coefficient of the array antenna is less than −10 dB from 8.88 GHz to 10.02 GHz. The measured gain of the array antenna is 13.3 dB on 9.5 GHz.

  18. X-band printed phased array antennas using high-performance CNT/ion gel/Ag transistors

    Science.gov (United States)

    Grubb, Peter M.; Bidoky, Fazel; Mahajan, Ankit; Subbaraman, Harish; Li, Wentao; Frisbie, Daniel; Chen, Ray T.

    2016-05-01

    This paper reports a fully printed phased array antenna developed on a 125 micron thick flexible Kapton substrate. Switching for the phase delay lines is accomplished using printed carbon nanotube transistors with ion gel dielectric layers. Design of each element of the phased array antenna is reported, including a low loss constant impedance power divider, a phase shifter network, and patch antenna design. Steering of an X-band PAA operating at 10GHz from 0 degrees to 22.15 degrees is experimentally demonstrated. In order to completely package the array with electrical interconnects, a single substrate interconnect scheme is also investigated.

  19. A Planar Reconfigurable Radiation Pattern Dipole Antenna with Reflectors and Directors for Wireless Communication Applications

    Directory of Open Access Journals (Sweden)

    Imen Ben Trad

    2014-01-01

    Full Text Available A planar printed dipole antenna with reflectors and directors, able to steer its radiation pattern in different directions, is proposed for telecommunication applications. Starting from a dual-beam printed dipole antenna achieved by combining two elementary dipoles back to back, and by loading four PIN diodes, three modes of reconfigurable radiation patterns are achieved at the frequency 2.56 GHz thanks to switches states. A prototype of the structure was realized and characterized; an efficiency of 75% is obtained. Simulation and measured results of the results are presented and discussed.

  20. Reconfigurable Yagi-Uda antenna based on a silicon reflector with a solid-state plasma.

    Science.gov (United States)

    Kim, Da-Jin; Park, Jang-Soon; Kim, Cheol Ho; Hur, Jae; Kim, Choong-Ki; Cho, Young-Kyun; Ko, Jun-Bong; Park, Bonghyuk; Kim, Dongho; Choi, Yang-Kyu

    2017-12-08

    This paper describes the fabrication and characterization of a reconfigurable Yagi-Uda antenna based on a silicon reflector with a solid-state plasma. The silicon reflector, composed of serially connected p-i-n diodes, forms a highly dense solid-state plasma by injecting electrons and holes into the intrinsic region. When this plasma silicon reflector is turned on, the front-realized gain of the antenna increases by more than 2 dBi beyond 5.3 GHz. To achieve the large gain increment, the structure of the antenna is carefully designed with the aid of semiconductor device simulation and antenna simulation. By using an aluminum nitride (AlN) substrate with high thermal conductivity, self-heating effects from the high forward current in the p-i-n diode are efficiently suppressed. By comparing the antenna simulation data and the measurement data, we estimated the conductivity of the plasma silicon reflector in the on-state to be between 104 and 105 S/m. With these figures, silicon material with its technology is an attractive tunable material for a reconfigurable antenna, which has attracted substantial interest from many areas, such as internet of things (IoT) applications, wireless network security, cognitive radio, and mobile and satellite communications as well as from multiple-input-multiple-output (MIMO) systems.

  1. A Double-Negative Metamaterial-Inspired Mobile Wireless Antenna for Electromagnetic Absorption Reduction.

    Science.gov (United States)

    Alam, Touhidul; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2015-07-29

    A double-negative metamaterial-inspired antenna is presented for mobile wireless applications. The antenna consists of a semi-circular radiating patch and a 3 × 4 hexagonal shaped metamaterial unit cell array in the ground plane. The antenna is fed with a 50 Ω microstrip feed line. The electric dimensions of the proposed antenna are 0.20λ × 0.26λ × 0.004λ, at the low-end frequency. The proposed antenna achieves a -10 dB impedance with a bandwidth of 2.29 GHz at the lower band and 1.28 GHz at the upper band and can operate for most of the mobile applications such as upper GSM bands, WiMAX, Bluetooth, and wireless local area network (WLAN) frequency bands. The focused novelties of the proposed antenna are its small size, multi-standard operating bands, and electromagnetic absorption reduction at all the operating frequencies using the double-negative metamaterial ground plane.

  2. Design and Analysis of Ultra-wideband Micro Strip Patch Antenna with Notch Band Characteristics

    Directory of Open Access Journals (Sweden)

    Kumar Omprakash

    2016-01-01

    Full Text Available A new design of ultra-wideband (UWB micro strip patch antenna with notch band characteristic for wireless local area network (WLAN application is presented in this paper. The proposed antenna consists of a rectangular patch with a partial ground plane that is fed by 50 Ω micro strip line. A notch band function is created by inserting overlapped one U-shape and one C-shape slot on the radiator patch, added additional patch to the ground plane side and slit in truncated ground plane. The proposed antenna potentially minimized frequency interference between WLAN and UWB system. This antenna with the size of 26 mm × 32 mm (W×L and the simulated results show that the antenna can operate over the frequency band between 3.1 and 10.45 GHz for voltage standing wave ratio (VSWR > 2 with band notch 5.06-5.825 GHz. Besides in the working band, the antenna shows good radiation pattern in the H-plane and the E-plane and has good time domain characteristic.

  3. Optimum Element Distribution for Circular Adaptive Antenna Systems

    National Research Council Canada - National Science Library

    Ulrey, Jonathan A; Gupta, Inder J

    2005-01-01

    The performance of circular, planar adaptive antennas is studied. The individual antenna elements are biconical antennas and the weights are adapted using space-only processing or space-time adaptive processing...

  4. School Starting Age and Crime

    DEFF Research Database (Denmark)

    Landersø, Rasmus; Nielsen, Helena Skyt; Simonsen, Marianne

    This paper investigates the effects of school starting age on crime while relying on variation in school starting age induced by administrative rules; we exploit that Danish children typically start first grade in the calendar year they turn seven, which gives rise to a discontinuity in children......’s school starting age. Analyses are carried out using register-based Danish data. We find that higher age at school start lowers the propensity to commit crime, but that this reduction is caused by incapacitation while human capital accumulation is unaffected. Importantly, we also find that the individuals...

  5. Analysis of a biconical antenna for EMC measurements

    Science.gov (United States)

    Gyoda, Koichi; Yamanaka, Yukio; Shinozuka, Takashi; Sugiura, Akira

    1995-06-01

    Broadband antennas, such as biconical antennas are widely used in automatic EMC measurements. However, there has been very little investigation of these types of antennas so far. Therefore, a numerical analysis is performed on a biconical antenna using moment methods. This paper presents calculation results of the input impedance, current distribution, height pattern of received voltage, and antenna factor. Measurement results of the height pattern and antenna factor are also presented and show very good agreement with calculated results.

  6. Proceedings of the 1985 Antenna Applications Symposium. Volume 1.

    Science.gov (United States)

    1985-12-01

    by tapering the center nomex honeycomb core such that the spacing varies from 0.92 inches to 1.34 inches as the angle of incidence varies from 20 to...Continue on rguerse if necessary and identify by block number) FIELD GROUP SUB. GR. Antennas Microstrip Multibeam Antennas U9 03 Satellite Antennas...1985 Antenna Applications Symposium is a collection of state-of-the-art papers relating to phased array antennas, multibeam antennas, satellite

  7. Experimental application of QCD antennas

    Energy Technology Data Exchange (ETDEWEB)

    Bobrovskyi, Sergei

    2010-02-15

    A serious problem in searches for new physics at the LHC is the rejection of QCD induced multijet events. In this thesis the formalism of QCD antenna variables based on the SPHEL approximation of QCD matrix elements is applied for the rst time on experimentally reconstructed jets in order to discriminate QCD from supersymmetric processes. The new observables provide additional information with respect to traditional event shape variables. Albeit correlated with experimentally measured missing transverse energy, the variables can be used to improve the signal to background ratio. (orig.)

  8. Near Field Antenna Measurement System.

    Science.gov (United States)

    1982-03-01

    points; the hard copy unit provides 200 dots /inch, across the 2-4 11-inch page and may generate as long a plot as required. These graphic peripherals have...Raster PHCUT pur.ose 37 36 XT 36D XT 37D UPSET arious MASTR HSCAN DEUCE _S.7 PM 1) Software supplied by Hewlett-Packard as part of the coriputer...program called DEUCE or special purpose analysis programs which provide production test data on the TPQ-36 or TPQ-37 antennas. These special programs

  9. Large space deployable antenna systems

    Science.gov (United States)

    1978-01-01

    The design technology is described for manufacturing a 20 m or larger space erectable antenna with high thermal stability, high dynamic stiffness, and minimum stowed size. The selected approach includes a wrap rib design with a cantilever beam basic element and graphite-epoxy composite lenticular cross section ribs. The rib configuration and powered type operated deploying mechanism are described and illustrated. Other features of the parabolic reflector discussed include weight and stowed diameter characteristics, structural dynamics characteristics, orbit thermal aperture limitations, and equivalent element and secondary (on axis) patterns. A block diagram of the multiple beam pattern is also presented.

  10. Antenna pattern study, task 2

    Science.gov (United States)

    Harper, Warren

    1989-01-01

    Two electromagnetic scattering codes, NEC-BSC and ESP3, were delivered and installed on a NASA VAX computer for use by Marshall Space Flight Center antenna design personnel. The existing codes and certain supplementary software were updated, the codes installed on a computer that will be delivered to the customer, to provide capability for graphic display of the data to be computed by the use of the codes and to assist the customer in the solution of specific problems that demonstrate the use of the codes. With the exception of one code revision, all of these tasks were performed.

  11. Solar energy collection by antennas

    Energy Technology Data Exchange (ETDEWEB)

    Corkish, R.; Green, M.A.; Puzzer, T. [University of New South Wales, Sydney (Australia). Centre for Advanced Silicon Photovoltaics and Photonics

    2002-12-01

    The idea of collecting solar electromagnetic radiation with antenna-rectifier (rectenna) structures was proposed three decades ago but has not yet been achieved. The idea has been promoted as having potential to achieve efficiency approaching 100% but thermodynamic considerations imply a lower limit of 85.4% for a non-frequency-selective rectenna and 86.8% for one with infinite selectivity, assuming maximal concentration in each case. This paper reviews the history and technical context of solar rectennas and discusses the major issues: thermodynamic efficiency limits, rectifier operation at optical frequencies, harmonics production and electrical noise. (author)

  12. Photonics-assisted wireless link based on mm-wave reconfigurable antennas

    DEFF Research Database (Denmark)

    Feliciano daCosta, Igor; Cerqueira Sodré, Arismar; Rodriguez Páez, Juan Sebastián

    2017-01-01

    is optically reconfigured by using photoconductive switches. In this way, the optical backhaul can either be used for high data rate transmission and remotely controlling the antenna operation. Experimental results on 40 Mbaud with complex modulation formats up to 64-QAM wireless transmission supported by PDC...... for access networks in the mm-wave frequency range....

  13. Apparatus and methods for packaging integrated circuit chips with antenna modules providing closed electromagnetic environment for integrated antennas

    Science.gov (United States)

    Gaucher, Brian P. (Inventor); Grzyb, Janusz (Inventor); Liu, Duixian (Inventor); Pfeiffer, Ullrich R. (Inventor)

    2008-01-01

    Apparatus and methods are provided for packaging IC chips together with integrated antenna modules designed to provide a closed EM (electromagnetic) environment for antenna radiators, thereby allowing antennas to be designed independent from the packaging technology.

  14. 4G antennas for wireless eyewear devices and related SAR

    Science.gov (United States)

    Cihangir, Aykut; Whittow, Will; Panagamuwa, Chinthana; Jacquemod, Gilles; Gianesello, Frédéric; Luxey, Cyril

    2015-11-01

    In this paper, we first present a feasibility study to design 4G antennas (700-960 MHz and 1.7-2.7 GHz) for eyewear devices. Those eyewear devices should be connected to the last generation cellular networks, Wireless Local Area Networks or wireless hotspots. Three coupling element type antennas with their matching networks are evaluated in terms of reflection coefficient and total radiation efficiency when the eyewear is placed on the user's head. We also present Specific Absorption Rate (SAR) simulations when the eyewear is positioned over a homogeneous SAM phantom and over a heterogeneous VH (Visible Human) phantom: the SAR levels are compared to international limit values. In a second step, we present experimental results obtained with 3D printed eyewear and coupling elements etched on a classical PCB substrate where the matching circuits are optimized close to the feeding point of the coupling element. Simulated and measured values are in very good agreement: 7 to 16% and 9 to 35% total efficiency are respectively obtained for the low- and high-frequency bands. However, simulated SAR values are somewhat higher than authorized levels with preoccupant high electromagnetic field distribution close to the eye of the user.

  15. A Geometrical-based Vertical Gain Correction for Signal Strength Prediction of Downtilted Base Station Antennas in Urban Areas

    DEFF Research Database (Denmark)

    Rodriguez, Ignacio; Nguyen, Huan Cong; Sørensen, Troels Bundgaard

    2012-01-01

    Base station antenna downtilt is one of the most important parameters for optimizing a cellular network with tight frequency reuse. By downtilting, inter-site interference is reduced, which leads to an improved performance of the network. In this study we show that a simple geometrical-based exte...

  16. Enabling Technologies for Fabrication of Large Area Flexible Antennas Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Flexible, foldable, and/or inflatable antenna systems open up a wealth of opportunities. Integrating antenna elements and related electronics onto flexible...

  17. Antenna allocation in MIMO radar with widely separated antennas for multi-target detection.

    Science.gov (United States)

    Gao, Hao; Wang, Jian; Jiang, Chunxiao; Zhang, Xudong

    2014-10-27

    In this paper, we explore a new resource called multi-target diversity to optimize the performance of multiple input multiple output (MIMO) radar with widely separated antennas for detecting multiple targets. In particular, we allocate antennas of the MIMO radar to probe different targets simultaneously in a flexible manner based on the performance metric of relative entropy. Two antenna allocation schemes are proposed. In the first scheme, each antenna is allocated to illuminate a proper target over the entire illumination time, so that the detection performance of each target is guaranteed. The problem is formulated as a minimum makespan scheduling problem in the combinatorial optimization framework. Antenna allocation is implemented through a branch-and-bound algorithm and an enhanced factor 2 algorithm. In the second scheme, called antenna-time allocation, each antenna is allocated to illuminate different targets with different illumination time. Both antenna allocation and time allocation are optimized based on illumination probabilities. Over a large range of transmitted power, target fluctuations and target numbers, both of the proposed antenna allocation schemes outperform the scheme without antenna allocation. Moreover, the antenna-time allocation scheme achieves a more robust detection performance than branch-and-bound algorithm and the enhanced factor 2 algorithm when the target number changes.

  18. EFFECT OF THE SUN UPON ANTENNA TEMPERATURE

    Science.gov (United States)

    temperature distributions over the sun at several frequencies are presented. The method by which antenna temperature is evaluated, using the Philco...calculate the variation of carrier-to-noise ratio as an antenna scans toward the sun while receiving signals from a deep-space probe and from a random-orbit satellite.

  19. Antenna Solar Energy to Electricity Converter (ASETEC)

    Science.gov (United States)

    1989-11-01

    electricity was produced. G. Conclusion: This technology needs further investigation to determine the most cost effective materials and the optimum...Electron Micrograph of Antenna Sensilla from Corn Earworm Moth............. 14 Greater Magnification Showing Fine Structure of Insect Antenna...Array................ 48 Measured Polar Diagram Tapered Rod and Different Wavelengths................... 49 Effect of Tube Wall Thickness on the

  20. ADAPTIVE ANTENNA ARRAY ALGORITHMS AND THEIR IMPACT ...

    African Journals Online (AJOL)

    direction of arrival of the signal on the antenna array. The matlab .... adaptive antenna is capable of automatically forming beams in the directions of the desired signals and forming nulls in the direction of the interfering signals. Hence by using the .... processing problems may be categorized as follows. Given the sampled ...

  1. Koch-Fractal Yagi-Uda Antenna

    DEFF Research Database (Denmark)

    Teisbæk, Henrik Bjørn; Jakobsen, Kaj Bjarne

    2009-01-01

    A Yagi-Uda antenna constructed of three Koch fractal elements is presented. Simulated and measured characteristics of the antenna shows a half-power beam-width of 64◦ achieved with dimensions below a third of a wavelength. Furthermore, the Koch dipole and its size miniaturization capabilities...

  2. GUI design exploration software for microwave antennas

    Directory of Open Access Journals (Sweden)

    Bo Liu

    2017-10-01

    Full Text Available Optimizers in commercial electromagnetic (EM simulation software packages are the main tools for performing antenna design exploration today. However, these general purpose optimizers are facing challenges in optimization efficiency, supported optimization types and usability for antenna experts without deep knowledge on optimization. Aiming to fill the gaps, a new antenna design exploration tool, called Antenna Design Explorer (ADE, is presented in this paper. The key features are: (1 State-of-the-art antenna design exploration methods are selected and embedded, addressing efficient antenna optimization (critical but unable to be solved by existing tools and multiobjective antenna optimization (not available in most existing tools; (2 Human-computer interaction for the targeted problem is studied, addressing various usability issues for antenna design engineers, such as automatic algorithmic parameter setting and interactive stopping criteria; (3 Compatibility with existing tools is studied and ADE is able to co-work with existing EM simulators and optimizers, combining advantages. A case study verifies the advantages of ADE.

  3. 47 CFR 80.863 - Antenna system.

    Science.gov (United States)

    2010-10-01

    ... MARITIME SERVICES Technical Equipment Requirements for Cargo Vessels Not Subject to Subpart W § 80.863... construction of the required antenna must insure operation in time of emergency. (b) If the required antenna is suspended between masts or other supports liable to whipping, a safety link which, under heavy stress, will...

  4. Fresnel zones for ground-based antennas

    DEFF Research Database (Denmark)

    Andersen, J. Bach

    1964-01-01

    The ordinary Fresnel zone concept is modified to include the influence of finite ground conductivity. This is important for ground-based antennas because the influence on the radiation pattern of irregularities near the antenna is determined by the amplitude and phase of the groundwave. A new...

  5. Multiple Antennas Arm Effective MIMO Systems

    DEFF Research Database (Denmark)

    Thaysen, Jesper; Jakobsen, Kaj Bjarne

    2007-01-01

    Understanding the interactions among different combinations of receive and transmit antenna elements can help increase the capacity of cellular wireless systems.......Understanding the interactions among different combinations of receive and transmit antenna elements can help increase the capacity of cellular wireless systems....

  6. Slot Antenna for Wireless Temperature Measurement Systems

    DEFF Research Database (Denmark)

    Acar, Öncel; Jakobsen, Kaj Bjarne

    2016-01-01

    This paper presents a novel clover-slot antenna for a surface-acoustic-wave sensor based wireless temperature measurement system. The slot is described by a parametric locus curve that has the shape of a clover. The antenna is operated at high temperatures, in rough environments, and has a 43...

  7. Features of Biconical Antenna Pulse Radiation

    Science.gov (United States)

    Legenkiy, M. M.

    2015-06-01

    Fields in bicone line and in free space are presented in the form of expansion over frequency-independent modes. Each mode possesses the dispersion depending on radius. With the mode matching method, the bicone antenna pulse radiation is calculated. It is shown that introducing some dielectric layer improves the antenna characteristics and allows to obtain the radiated field with higher amplitude.

  8. 47 CFR 73.753 - Antenna systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 73.753 Section 73.753 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES International Broadcast Stations § 73.753 Antenna systems. All international broadcasting stations shall operate...

  9. D fibre antenna for microcellular communications

    CERN Document Server

    Bhatti, A A

    2003-01-01

    Over the years, optical fibre sensors have been developed for many application areas. With the recent growth of microcellular communication systems this area has great economic potential. Therefore with this in mind one promising application for a new optical fibre sensor system is in the detection of Radio Frequency/Electric Fields (RF/EF). By constructing such a sensor from totally dielectric materials, it could be used as an antenna for receiving radio frequency transmissions without distorting or disturbing the field lines since there are no metallic components to reflect or transmit radio frequency energy. One of the key issues in the realisation of Radio-over-Fibre (RoF) architecture is the development of an effective means of generating and transmitting the radio subcarrier. The simplest method for the optical generation of radio signals, for transmission through an optical network is to directly modulate the light source with the received RF signal. Direct modulation of the laser can lead to a number ...

  10. Assessment of the underground construction details of a road pavement using GPR antenna systems with different frequencies

    Science.gov (United States)

    Alani, Amir M.; Tosti, Fabio; Bianchini Ciampoli, Luca; Benedetto, Francesco; Benedetto, Andrea

    2017-04-01

    intervals in the direction of the road started from the reference (first) transversal axis located 5m behind the drain at the side of the road. The results obtained using the 2000 MHz antenna showed that the road construction consisted of an asphalt layer of 10 cm thickness overlaying a reinforced concrete block with two layers of rebar mesh. In addition, significant moisture damage and evidence of subsidence within the road were identified. The 900 MHz frequency antenna confirmed the above results as well as suggesting the existence of subsidence at the lower areas of the road foundation. Furthermore, results revealed the existence of an unidentified object at the deeper depth. This was not detected by the higher frequency antenna. The maximum depth of penetration was achieved by using the 600 MHz and the 200 MHz antennas (maximum of 3 m). To that effect this investigation did not identify or confirm the existence of any underground watercourse. Acknowledgement The authors acknowledge the COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" for providing networking and discussion opportunities throughout its activity and operation as well as facilitating prospect for publishing research outputs.

  11. Enhancing molecule fluorescence with asymmetrical plasmonic antennas.

    Science.gov (United States)

    Lu, Guowei; Liu, Jie; Zhang, Tianyue; Shen, Hongming; Perriat, Pascal; Martini, Matteo; Tillement, Olivier; Gu, Ying; He, Yingbo; Wang, Yuwei; Gong, Qihuang

    2013-07-21

    We propose and justify by the finite-difference time-domain method an efficient strategy to enhance the spontaneous emission of a fluorophore with a multi-resonance plasmonic antenna. The custom-designed asymmetrical antenna consists of two plasmonic nanoparticles with different sizes and is able to couple efficiently to free space light through multiple localized surface plasmon resonances. This design simultaneously permits a large near-field excitation near the antenna as well as a high quantum efficiency, which results in an unusual and significant enhancement of the fluorescence of a single emitter. Such an asymmetrical antenna presents intrinsic advantages over single particle or dimer based antennas made using two identical nanostructures. This promising concept can be exploited in the large domain of light-matter interaction processes involving multiple frequencies.

  12. Extreme Precision Antenna Reflector Study Results

    Science.gov (United States)

    Sharp, G. R.; Gilger, L. D.; Ard, K. E.

    1985-01-01

    Thermal and mechanical distortion degrade the RF performance of antennas. The complexity of future communications antennas requires accurate, dimensionally stable antenna reflectors and structures built from materials other than those currently used. The advantages and disadvantages of using carbon fibers in an epoxy matrix are reviewed as well as current reflector fabrications technology and adjustment. The manufacturing sequence and coefficient of thermal expansion of carbon fiber/borosilicate glass composites is described. The construction of a parabolic reflector from this material and the assembling of both reflector and antenna are described. A 3M-aperture-diameter carbon/glass reflector that can be used as a subassembly for large reflectors is depicted. The deployment sequence for a 10.5M-aperture-diameter antenna, final reflector adjustment, and the deployment sequence for large reflectors are also illustrated.

  13. Antenna organization in green photosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Blankenship, R.E.

    1987-01-01

    This project is concerned with the structure and function of the unique antenna system found in the green photosynthetic bacteria. The antenna system in these organisms is contained within a vesicle known as a chlorosome, which is attached to the cytoplasmic side of the cell membrane. Additional antenna pigments and reaction centers are contained in integral membrane proteins. Energy absorbed by the bacteriochlorophyll c (BChl c) pigments in the chlorosome is transferred via a baseplate'' array of BChl a antenna pigments into the membrane and to the reaction center. A schematic model of chlorosome structure is shown. This project is aimed at increasing our understanding of the organization of the pigments in the chlorosome and how the antenna system functions.

  14. Antenna Pattern Impact on MIMO OTA Testing

    DEFF Research Database (Denmark)

    Fan, Wei; Nielsen, Jesper Ødum; Franek, Ondrej

    2013-01-01

    This paper investigates the impact of the DUT antenna pattern on the test area performance for multi-probe based MIMO OTA setup in terms of received voltage and spatial correlation. The plane wave synthesis (PWS) technique has been proposed for vertical polarization in the literature, where...... the goal is to approximate plane waves with arbitrary directions. The received voltage at the antenna terminal depends on the antenna radiation pattern and the impinging plane waves. A novel closed form technique to reproduce the received voltage with arbitrary incoming plane waves based on trigonometric...... of the antenna pattern on spatial correlation accuracy for prefaded signal synthesis (PFS) technique is investigated as well. Simulation and measurement results show that the number of required probes depend directly on the DUT antenna pattern. To test realistic DUTs with higher variations in directivity, we...

  15. Study on Horizontally Polarized Omnidirectional Microstrip Antenna

    Directory of Open Access Journals (Sweden)

    Kun Wei

    2016-01-01

    Full Text Available A horizontally polarized omnidirectional microstrip antenna is proposed in this paper. The structure of designed antenna is with two back-to-back horizontally polarized microstrip antenna elements. Gain variation on main radiation plane of this new antenna is analyzed and radiation theory is deduced; formula of directivity on main radiation plane is given. Better omnidirectional characteristic of this antenna can be obtained by decreasing patch physical length. Both simulated and measured results verify the omnidirectional radiation patterns and input impedance characteristics. Good omnidirectional radiation patterns (gain variation in E-plane less than ±0.4 dBi and input impedance characteristics are obtained; moreover, cross polarization less than −20 dBi is achieved.

  16. 5G MIMO Conformal Microstrip Antenna Design

    Directory of Open Access Journals (Sweden)

    Qian Wang

    2017-01-01

    Full Text Available With the development of wireless communication technology, 5G will develop into a new generation of wireless mobile communication systems. MIMO (multiple-input multiple-output technology is expected to be one of the key technologies in the field of 5G wireless communications. In this paper, 4 pairs of microstrip MIMO conformal antennas of 35 GHz have been designed. Eight-element microstrip Taylor antenna array with series-feeding not only achieves the deviation of the main lobe of the pattern but also increases the bandwidth of the antenna array and reduces sidelobe. MIMO antennas have been fabricated and measured. Measurement results match the simulation results well. The return loss of the antenna at 35 GHz is better than 20 dB, the first sidelobe level is −16 dB, and the angle between the main lobe and the plane of array is 60°.

  17. Present capabilities and new developments in antenna modeling with the numerical electromagnetics code NEC

    Energy Technology Data Exchange (ETDEWEB)

    Burke, G.J.

    1988-04-08

    Computer modeling of antennas, since its start in the late 1960's, has become a powerful and widely used tool for antenna design. Computer codes have been developed based on the Method-of-Moments, Geometrical Theory of Diffraction, or integration of Maxwell's equations. Of such tools, the Numerical Electromagnetics Code-Method of Moments (NEC) has become one of the most widely used codes for modeling resonant sized antennas. There are several reasons for this including the systematic updating and extension of its capabilities, extensive user-oriented documentation and accessibility of its developers for user assistance. The result is that there are estimated to be several hundred users of various versions of NEC world wide. 23 refs., 10 figs.

  18. Antennas.

    Science.gov (United States)

    1982-03-03

    the corrugating device. The tube is corrugated by a wheel which turns in a medium of lubricating and cooling emulsions . Radial movement of the turning...copper with thickness of the order of 0.5 mm. An anticorrosive bitumen -based composition coats the outside surface of the corrugated elliptical tube

  19. Antennas.

    Science.gov (United States)

    1982-05-13

    resoect to the desl -r--d Zunction f(x), isz nonlinear . And, finall-7, problem 4 red’uces to a nonlin-r n- te-oral equatio’n after simple transfo:rmations...radiation patterns for a round aperture: -- ---- with maximum slope at u=O; with a maximum level of first lobe. Maximizing the Amplitude of the Major

  20. Telecommunications Antennas for the Juno Mission to Jupiter

    Science.gov (United States)

    Vacchione, Joseph D.; Kruid, Ronald C.; Prata, Aluizio, Jr.; Amaro, Luis R.; Mittskus, Anthony P.

    2012-01-01

    The Juno Mission to Jupiter requires a full sphere of coverage throughout its cruise to and mission at Jupiter. This coverage is accommodated through the use of five (5) antennas; forward facing low gain, medium gain, and high gain antennas, and an aft facing low gain antenna along with an aft mounted low gain antenna with a torus shaped antenna pattern. Three of the antennas (the forward low and medium gain antennas) are classical designs that have been employed on several prior NASA missions. Two of the antennas employ new technology developed to meet the Juno mission requirements. The new technology developed for the low gain with torus shaped radiation pattern represents a significant evolution of the bicone antenna. The high gain antenna employs a specialized surface shaping designed to broaden the antenna's main beam at Ka-band to ease the requirements on the spacecraft's attitude control system.