Receive antenna selection for underlay cognitive radio with instantaneous interference constraint

KAUST Repository

Hanif, Muhammad Fainan

2015-06-01

Receive antenna selection is a low complexity scheme to reap diversity benefits.We analyze the performance of a receive antenna selection scheme in spectrum sharing systems where the antenna that results in highest signal-to-interference plus noise ratio at the secondary receiver is selected to improve the performance of secondary transmission. Exact and asymptotic behaviours of the received SINR are derived for both general and interference limited scenarios over general fading environment. These results are then applied to the outage and average bit error rate analysis when the secondary transmitter changes the transmit power in finite discrete levels to satisfy the instantaneous interference constraint at the primary receiver.

Timing-Free Blind Multiuser Detection for Multicarrier DS/CDMA Systems with Multiple Antennae

Directory of Open Access Journals (Sweden)

Stefano Buzzi

2004-05-01

Full Text Available The problem of blind multiuser detection for an asynchronous multicarrier DS-CDMA system employing multiple transmit and receive antennae over a Rayleigh fading channel is considered in this paper. The solutions that we develop require prior knowledge of the spreading code of the user to be decoded only, while no further information either on the user to be decoded or on the other active users is required. Several combining rules for the observables at the output of each receive antenna are proposed and assessed, and the implications of the different options are studied in depth in terms of both detection performance and computational complexity. A closed form expression is also derived for the conditional error probability and a lower bound for the near-far resistance is provided. Results confirm that the proposed blind receivers can cope with both multiple access interference suppression and channel estimation at the price of a limited performance loss as compared to the ideal linear receivers which assume perfect channel state information.

Miniaturization of Multiple-Layer Folded Patch Antennas

DEFF Research Database (Denmark)

Zhang, Jiaying; Breinbjerg, Olav

2009-01-01

A new folded patch antenna with multiple layers was developed in this paper, by folding the patch in a proper way, and a highly miniaturized antenna can be realized. The multiple layer patch with 4-layer and 6-layer are designed and evaluated at 2.4 GHz, 915 MHz, and 415 MHz respectively. Then a 4...... layer patch is fabricated and measured to validate the design method. The theoretical analysis, design and simulations, fabrications, as well as the measurements are presented in this paper. All the results show that the folded patch antenna is a good candidate in making a highly miniaturized compact...

Cross-Layer Design for Two-Way Relaying Networks with Multiple Antennas

Directory of Open Access Journals (Sweden)

zhuo wu

2015-10-01

Full Text Available In this paper, we developed a cross-layer design for two-way relaying (TWR networks with multiple antennas, where two single antenna source nodes exchange information with the aid of one multiple antenna relay node. The proposed cross-layer design considers adaptive modulation (AM and space-time block coding (STBC at the physical layer with an automatic repeat request (ARQ protocol at the data link layer, in order to maximize the spectral efficiency under specific delay and packet error ratio (PER constraints. An MMSE-interference cancellation (IC receiver is employed at the relay node, to remove the interference in the fist phase of the TWR transmission. The transmission mode is updated for each phase of the TWR transmission on a frame-by-frame basis, to match the time-varying channel conditions and exploit the system performance and throughput gain. Simulation results show that retransmission at the data link layer could alleviate rigorous error-control requirements at the physical layer, and thereby allows higher data transmission. As a result, cross-layer design helps to achieve considerable system spectral efficiency gain for TWR networks, compared to those without cross-layer design.

Development And Test of A Digitally Steered Antenna Array for The Navigator GPS Receiver

Science.gov (United States)

Pinto, Heitor David; Valdez, Jennifer E.; Winternitz, Luke M. B.; Hassouneh, Munther A.; Price, Samuel R.

2012-01-01

Global Positioning System (GPS)-based navigation has become common for low-Earth orbit spacecraft as the signal environment is similar to that on the Earth s surface. The situation changes abruptly, however, for spacecraft whose orbital altitudes exceed that of the GPS constellation. Visibility is dramatically reduced and signals that are present may be very weak and more susceptible to interference. GPS receivers effective at these altitudes require increased sensitivity, which often requires a high-gain antenna. Pointing such an antenna can pose a challenge. One efficient approach to mitigate these problems is the use of a digitally steered antenna array. Such an antenna can optimally allocate gain toward desired signal sources and away from interferers. This paper presents preliminary results in the development and test of a digitally steered antenna array for the Navigator GPS research program at NASA s Goddard Space Flight Center. In particular, this paper highlights the development of an array and front-end electronics, the development and test of a real-time software GPS receiver, and implementation of three beamforming methods for combining the signals from the array. Additionally, this paper discusses the development of a GPS signal simulator which produces digital samples of the GPS L1C/A signals as they would be received by an arbitrary antenna array configuration. The simulator models transmitter and receiver dynamics, near-far and multipath interference, and has been a critical component in both the development and test of the GPS receiver. The GPS receiver system was tested with real and simulated GPS signals. Preliminary results show that performance improvement was achieved in both the weak signal and interference environments, matching analytical predictions. This paper summarizes our initial findings and discusses the advantages and limitations of the antenna array and the various beamforming methods.

Effective capacity of multiple antenna channels: Correlation and keyhole

KAUST Repository

Zhong, Caijun

2012-01-01

In this study, the authors derive the effective capacity limits for multiple antenna channels which quantify the maximum achievable rate with consideration of link-layer delay-bound violation probability. Both correlated multiple-input single-output and multiple-input multiple-output keyhole channels are studied. Based on the closed-form exact expressions for the effective capacity of both channels, the authors look into the asymptotic high and low signal-to-noise ratio regimes, and derive simple expressions to gain more insights. The impact of spatial correlation on effective capacity is also characterised with the aid of a majorisation theory result. It is revealed that antenna correlation reduces the effective capacity of the channels and a stringent quality-of-service requirement causes a severe reduction in the effective capacity but can be alleviated by increasing the number of antennas. © 2012 The Institution of Engineering and Technology.

Low-Profile, Dual-Wavelength, Dual-Polarized Antenna

Science.gov (United States)

Carswell, James R.

2010-01-01

A single-aperture, low-profile antenna design has been developed that supports dual-polarization and simultaneous operation at two wavelengths. It realizes multiple beams in the elevation plane, and supports radiometric, radar, and conical scanning applications. This antenna consists of multiple azimuth sticks, with each stick being a multilayer, hybrid design. Each stick forms the h-plane pattern of the C and Ku-band vertically and horizontally polarized antenna beams. By combining several azimuth sticks together, the elevation beam is formed. With a separate transceiver for each stick, the transmit phase and amplitude of each stick can be controlled to synthesize a beam at a specific incidence angle and to realize a particular side-lobe pattern. By changing the transmit phase distribution through the transceivers, the transmit antenna beam can be steered to different incidence angles. By controlling the amplitude distribution, different side lobe patterns and efficiencies can be realized. The receive beams are formed using digital beam synthesis techniques, resulting in very little loss in the receive path, thus enabling a very-low loss receive antenna to support passive measurements.

New perspective on single-radiator multiple-port antennas for adaptive beamforming applications.

Science.gov (United States)

Byun, Gangil; Choo, Hosung

2017-01-01

One of the most challenging problems in recent antenna engineering fields is to achieve highly reliable beamforming capabilities in an extremely restricted space of small handheld devices. In this paper, we introduce a new perspective on single-radiator multiple-port (SRMP) antenna to alter the traditional approach of multiple-antenna arrays for improving beamforming performances with reduced aperture sizes. The major contribution of this paper is to demonstrate the beamforming capability of the SRMP antenna for use as an extremely miniaturized front-end component in more sophisticated beamforming applications. To examine the beamforming capability, the radiation properties and the array factor of the SRMP antenna are theoretically formulated for electromagnetic characterization and are used as complex weights to form adaptive array patterns. Then, its fundamental performance limits are rigorously explored through enumerative studies by varying the dielectric constant of the substrate, and field tests are conducted using a beamforming hardware to confirm the feasibility. The results demonstrate that the new perspective of the SRMP antenna allows for improved beamforming performances with the ability of maintaining consistently smaller aperture sizes compared to the traditional multiple-antenna arrays.

New perspective on single-radiator multiple-port antennas for adaptive beamforming applications.

Directory of Open Access Journals (Sweden)

Gangil Byun

Full Text Available One of the most challenging problems in recent antenna engineering fields is to achieve highly reliable beamforming capabilities in an extremely restricted space of small handheld devices. In this paper, we introduce a new perspective on single-radiator multiple-port (SRMP antenna to alter the traditional approach of multiple-antenna arrays for improving beamforming performances with reduced aperture sizes. The major contribution of this paper is to demonstrate the beamforming capability of the SRMP antenna for use as an extremely miniaturized front-end component in more sophisticated beamforming applications. To examine the beamforming capability, the radiation properties and the array factor of the SRMP antenna are theoretically formulated for electromagnetic characterization and are used as complex weights to form adaptive array patterns. Then, its fundamental performance limits are rigorously explored through enumerative studies by varying the dielectric constant of the substrate, and field tests are conducted using a beamforming hardware to confirm the feasibility. The results demonstrate that the new perspective of the SRMP antenna allows for improved beamforming performances with the ability of maintaining consistently smaller aperture sizes compared to the traditional multiple-antenna arrays.

Impact of Antenna Placement on Frequency Domain Adaptive Antenna Array in Hybrid FRF Cellular System

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Sri Maldia Hari Asti

2012-01-01

Full Text Available Frequency domain adaptive antenna array (FDAAA is an effective method to suppress interference caused by frequency selective fading and multiple-access interference (MAI in single-carrier (SC transmission. However, the performance of FDAAA receiver will be affected by the antenna placement parameters such as antenna separation and spread of angle of arrival (AOA. On the other hand, hybrid frequency reuse can be adopted in cellular system to improve the cellular capacity. However, optimal frequency reuse factor (FRF depends on the channel propagation and transceiver scheme as well. In this paper, we analyze the impact of antenna separation and AOA spread on FDAAA receiver and optimize the cellular capacity by using hybrid FRF.

Effective capacity of multiple antenna channels: Correlation and keyhole

KAUST Repository

Zhong, Caijun; Ratnarajah, Tharm; Wong, Kaikit; Alouini, Mohamed-Slim

2012-01-01

In this study, the authors derive the effective capacity limits for multiple antenna channels which quantify the maximum achievable rate with consideration of link-layer delay-bound violation probability. Both correlated multiple-input single

Simultaneous energy harvesting and information processing in wireless multiple relays with multiple antennas

Science.gov (United States)

Albaaj, Azhar; Makki, S. Vahab A.; Alabkhat, Qassem; Zahedi, Abdulhamid

2017-07-01

Wireless networks suffer from battery discharging specially in cooperative communications when multiple relays have an important role but they are energy constrained. To overcome this problem, energy harvesting from radio frequency signals is applied to charge the node battery. These intermediate nodes have the ability to harvest energy from the source signal and use the energy harvested to transmit information to the destination. In fact, the node tries to harvest energy and then transmit the data to destination. Division of energy harvesting and data transmission can be done in two algorithms: time-switching-based relaying protocol and power-splitting-based relaying protocol. These two algorithms also can be applied in delay-limited and delay-tolerant transmission systems. The previous works have assumed a single relay for energy harvesting, but in this article, the proposed method is concentrated on improving the outage probability and throughput by using multiple antennas in each relay node instead of using single antenna. According to our simulation results, when using multi-antenna relays, ability of energy harvesting is increased and thus system performance will be improved to great extent. Maximum ratio combining scheme has been used when the destination chooses the best signal of relays and antennas satisfying the required signal-to-noise ratio.

Statistical Evaluation of the Azimuth and Elevation Angles Seen at the Output of the Receiving Antenna

Science.gov (United States)

Ziolkowski, Cezary; Kelner, Jan M.

2018-04-01

A method to evaluate the statistical properties of the reception angle seen at the input receiver that considers the receiving antenna pattern is presented. In particular, the impact of the direction and beamwidth of the antenna pattern on distribution of the reception angle is shown on the basis of 3D simulation studies. The obtained results show significant differences between distributions of angle of arrival and angle of reception. This means that the presented new method allows assessing the impact of the receiving antenna pattern on the correlation and spectral characteristics at the receiver input in simulation studies of wireless channel. The use of this method also provides an opportunity for analysis of a co-existence between small cells and wireless backhaul, what is currently a significant problem in designing 5G networks.

Investigations of Relatively Easy To Construct Antennas With Efficiency in Receiving Schumann Resonances: Preparations for a Miniaturized Reconfigurable ELF Receiver

Science.gov (United States)

Farmer, Brian W.; Hannan, Robert C.

2003-01-01

Relatively little is known about the cavity between the Earth and the ionosphere, which opens opportunities for technological advances and unique ideas. One effective means to study this cavity is with extremely low frequency (ELF) antennas. Possible applications of these antennas are global weather prediction, earthquake prediction, planetary exploration, communication, wireless transmission of power, or even a free energy source. The superconducting quantum interference device SQUID) and the coil antenna are the two most acceptable receivers discovered for picking up ELF magnetic fields. Both antennas have the potential for size reduction, allowing them to be portable enough for access to space and even for personal ware. With improvements of these antennas and signal processing, insightful analysis of Schumann resonance (SR) can give the science community a band of radio frequency (RF) signals for improving life here on Earth and exploring beyond.

The development of the miniaturized waveform receiver with the function measuring Antenna Impedance in space plasmas

Science.gov (United States)

Ishii, H.; Kojima, H.; Fukuhara, H.; Okada, S.; Yamakawa, H.

2012-04-01

Plasma wave is one of the most essential physical quantities in the solar terrestrial physics. The role of plasma wave receiver onboard satellites is to detect plasma waves in space with a good signal to noise ratio. There are two types of plasma wave receivers, the sweep frequency analyzer and the waveform capture. While the sweep frequency analyzer provides plasma wave spectra, the waveform capture obtains waveforms with phase information that is significant in studying nonlinear phenomena. Antenna sensors to observe electric fields of the plasma waves show different features in plasmas from in vacuum. The antenna impedances have specific characteristics in the frequency domain because of the dispersion of plasmas. These antenna impedances are expressed with complex number. We need to know not only the antenna impedances but also the transfer functions of plasma wave receiver's circuits in order to calibrate observed waveforms precisely. The impedances of the electric field antennas are affected by a state of surrounding plasmas. Since satellites run through various regions with different plasma parameters, we precisely should measure the antenna impedances onboard spacecraft. On the contrary, we can obtain the plasma density and by measuring the antenna impedances. Several formulas of the antenna impedance measurement system were proposed. A synchronous detection method is used on the BepiColombo Mercury Magnetospheric Orbiter (MMO), which will be launched in 2014. The digital data are stored in the onboard memory. They are read out and converted to the analog waveforms by D/A converter. They are fed into the input of the preamplifiers of antenna sensors through a resistor. We can calculate a transfer function of the circuit by applying the synchronous detection method to the output waveform from waveform receivers and digital data as a signal source. The size of this system is same as an A5 board. In recent years, Application Specific Integrated Circuit (ASIC

Effective Length of a Receiving Antenna in a Streaming Plasma

Czech Academy of Sciences Publication Activity Database

Chugunov, Yu. V.; Fiala, Vladimír

2006-01-01

Roč. 54, č. 10 (2006), s. 2750-2756 ISSN 0018-926X R&D Projects: GA AV ČR IAA301120601 Institutional research plan: CEZ:AV0Z30420517 Keywords : receiving antenna * plasma waves * resonance Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.480, year: 2006

One- and two-dimensional antenna arrays for microwave wireless power transfer (MWPT) systems and dual-antenna transceivers

Science.gov (United States)

Lin, Yo-Sheng; Hu, Chun-Hao; Chang, Chi-Ho; Tsao, Ping-Chang

2018-06-01

In this work, we demonstrate novel one-dimensional (1D) and two-dimensional (2D) antenna arrays for both microwave wireless power transfer (MWPT) systems and dual-antenna transceivers. The antenna array can be used as the MWPT receiving antenna of an integrated MWPT and Bluetooth (BLE) communication module (MWPT-BLE module) for smart CNC (computer numerical control) spindle incorporated with the cloud computing system SkyMars. The 2D antenna array has n rows of 1 × m 1D array, and each array is composed of multiple (m) differential feeding antenna elements. Each differential feeding antenna element is a differential feeding structure with a microstrip antenna stripe. The stripe length is shorter than one wavelength to minimise the antenna area and to prevent being excited to a high-order mode. That is, the differential feeding antenna element can suppress the even mode. The mutual coupling between the antenna elements can be suppressed, and the isolation between the receiver and the transmitter can be enhanced. An inclination angle of the main beam aligns with the broadside, and the main beam is further concentrated and shrunk at the elevation direction. Moreover, if more differential feeding antenna elements are used, antenna gain and isolation can be further enhanced. The excellent performance of the proposed antenna arrays indicates that they are suitable for both MWPT systems and dual-antenna transceivers.

The Implementation of a 2/4/8 Antennas Configurable Diversity OFDM Receiver for Mobile HDTV Application

Directory of Open Access Journals (Sweden)

Jing Gao

2009-01-01

Full Text Available Two pre-FFT adaptive array (AA antenna combiners and a post-FFT carrier diversity (CD combiner are integrated with a Japan Terrestrial digital TV (ISDB-T OFDM receiver using 90 nm 7M1P CMOS process. A 2/4/8-antenna diversity receiver can be configured and a low-cost 4 antenna diversity reception system can be realized in one LSI by making use of the AA-CD two-stage diversity combining method. Mobile reception performance is increased by 1.63 times using a denoise filter circuit and SPLINE interpolator under urban 6-path Rayleigh fading (TU6 model with 2-antenna post-FFT carrier diversity (2CD combing mode. The die area is 49 mm2 and the power consumption is 310 mW.

Joint switched multi-spectrum and transmit antenna diversity for spectrum sharing systems

KAUST Repository

Sayed, Mostafa M.; Abdallah, Mohamed M.; Qaraqe, Khalid A.; Alouini, Mohamed-Slim

2013-01-01

. In this paper, we consider a secondary network comprised of a secondary transmitter (SU-Tx) equipped with multiple antennas and a single-antenna secondary receiver (SU-Rx) sharing the same spectrum with multiple primary users (PUs), each with a distinct spectrum

On the Required Number of Antennas in a Point-to-Point Large-but-Finite MIMO System

KAUST Repository

Makki, Behrooz; Svensson, Tommy; Eriksson, Thomas; Alouini, Mohamed-Slim

2015-01-01

In this paper, we investigate the performance of the point-to-point multiple-input-multiple-output (MIMO) systems in the presence of a large but finite numbers of antennas at the transmitters and/or receivers. Considering the cases with and without hybrid automatic repeat request (HARQ) feedback, we determine the minimum numbers of the transmit/receive antennas which are required to satisfy different outage probability constraints. We study the effect of the spatial correlation between the antennas on the system performance. Also, the required number of antennas are obtained for different fading conditions. Our results show that different outage requirements can be satisfied with relatively few transmit/receive antennas. © 2015 IEEE.

On the Required Number of Antennas in a Point-to-Point Large-but-Finite MIMO System

KAUST Repository

Makki, Behrooz

2015-11-12

In this paper, we investigate the performance of the point-to-point multiple-input-multiple-output (MIMO) systems in the presence of a large but finite numbers of antennas at the transmitters and/or receivers. Considering the cases with and without hybrid automatic repeat request (HARQ) feedback, we determine the minimum numbers of the transmit/receive antennas which are required to satisfy different outage probability constraints. We study the effect of the spatial correlation between the antennas on the system performance. Also, the required number of antennas are obtained for different fading conditions. Our results show that different outage requirements can be satisfied with relatively few transmit/receive antennas. © 2015 IEEE.

Mutual coupling investigation between a loop and two inverted-l antennas operating below 1 GHz

DEFF Research Database (Denmark)

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

2015-01-01

To overcome antenna design challenges posed by the increasing number of frequency bands, the use of separate transmit (Tx) and receive (Rx) narrow-band antennas is proposed. In addition, a second Rx antenna is utilised for multiple input-multiple output (MIMO) application. While sufficiently low ...

Determining of the phase centre of the real position of GPS receiver antenna

Directory of Open Access Journals (Sweden)

Eva Pisoňová

2007-06-01

Full Text Available By continued improvement of measurement methods producers of GPS (Global Positioning System apparatus will be maybe once upon a time effective to minimize a difference of the phase centre from the geometrical one, because it is probably impossible to make the GPS receiver antenna with zero eccentricity of the phase centre. In the last analysis, we do not prevent from a manufacturing error by any way in eliminate of the possible measurement errors.In the paper there is presented the measurement testing practice with aim of the phase centre real position determining of several in a market available GPS receivers in the paper. Investigation up to what standard the GPS receiver antenna phase centre variation achieves to float in an inaccuracy into GPS measurements. Testing was realized on the temporary testing baseline closely village Badín at Banská Bystrica in the Central Slovak Region. GPS receivers Locus Survey System (Ashtech, ProMark2 (Ashtech were tested.

Duplex Schemes in Multiple Antenna Two-Hop Relaying

Directory of Open Access Journals (Sweden)

Anja Klein

2008-04-01

Full Text Available A novel scheme for two-hop relaying defined as space division duplex (SDD relaying is proposed. In SDD relaying, multiple antenna beamforming techniques are applied at the intermediate relay station (RS in order to separate downlink and uplink signals of a bi-directional two-hop communication between two nodes, namely, S1 and S2. For conventional amplify-and-forward two-hop relaying, there appears a loss in spectral efficiency due to the fact that the RS cannot receive and transmit simultaneously on the same channel resource. In SDD relaying, this loss in spectral efficiency is circumvented by giving up the strict separation of downlink and uplink signals by either time division duplex or frequency division duplex. Two novel concepts for the derivation of the linear beamforming filters at the RS are proposed; they can be designed either by a three-step or a one-step concept. In SDD relaying, receive signals at S1 are interfered by transmit signals of S1, and receive signals at S2 are interfered by transmit signals of S2. An efficient method in order to combat this kind of interference is proposed in this paper. Furthermore, it is shown how the overall spectral efficiency of SDD relaying can be improved if the channels from S1 and S2 to the RS have different qualities.

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.

Clear air boundary layer spaced antenna wind measurement with the Multiple Antenna Profiler (MAPR

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S. A. Cohn

Full Text Available Spaced antenna (SA wind measurement techniques are applied to Multiple Antenna Profiler (MAPR data to evaluate its performance in clear air conditions. MAPR is a multiple antenna 915 MHz wind profiler developed at the National Center for Atmospheric Research (NCAR and described in Cohn et al. (1997, designed to make high resolution wind measurements. Previous reported measurements with MAPR were restricted to precipitation because of low signal to noise (SNR and signal to ground-clutter (SCR ratios. By using a standard pulse-coding technique and upgrading the profiler control software, increases in average power and SNR were achieved, making routine measurements in clear air possible. Comparison of winds measured by MAPR and by a sonic anemometer on a nearby 300 m tower show correlation coefficients in the range of R² = 0.75 – 0.80, and an average absolute error of ~ 1.4 m s - 1 . This compares favorably with the agreement typically found in wind profiler comparisons. We also consider the use of the parameter ah , which is related to the value of the cross-correlation function at its zero crossing. This parameter is a data quality indicator and possibly a key component in a ground clutter removal technique.

Key words. Meteorology and atmospheric dynamics (mesoscale meteorology; instruments and techniques – Radio science (remote sensing

Secret-key agreement over spatially correlated fast-fading multiple-antenna channels with public discussion

KAUST Repository

Zorgui, Marwen

2015-06-14

We consider secret-key agreement with public discussion over multiple-input multiple-output (MIMO) Rayleigh fast-fading channels under correlated environment. We assume that transmit, legitimate receiver and eavesdropper antennas are correlated. The legitimate receiver and the eavesdropper are assumed to have perfect channel knowledge while the transmitter has only knowledge of the correlation matrices. First, we derive the expression of the secret-key capacity under the considered setup. Then, we prove that the optimal transmit strategy achieving the secret-key capacity consists in transmitting independent Gaussian signals along the eingenvectors of the transmit correlation matrix. The powers allocated to each channel mode are determined as the solution to a numerical optimization problem that we derive. A necessary and sufficient condition for beamforming (i.e., transmitting along the strongest channel mode) to be capacity-achieving is derived. Finally, we analyze the impact of correlation matrices on the system performance and provide closed-form expressions of the gain/loss due to correlation in the high power regime.

Multiple-Active Multiple-Passive Antenna Systems and Applications

DEFF Research Database (Denmark)

Tsakalaki, Elpiniki

2013-01-01

-passive (MAMP) antenna topologies, as explained in Sect. 8.1. Then, Sect. 8.2 proposes MAMP antenna structures with application to reconfigurable MIMO transmission in the presence of antenna mutual coupling under poor scattering channel conditions. For this purpose, the section presents an adaptive MAMP antenna...... system capable of changing its transmission parameters via passive radiators attached to tunable loads, according to the structure of the RF propagation channel. The hybrid MAMP array structure can be tractably analyzed using the active element response vector (instead of the classical steering vector...... adaptive MAMP system can be limited to practical dimensions whereas the passive antennas require no extra RF hardware, thus meeting the cost, space, and power constrains of the users’ mobile terminals. The simulation results show that the adaptive MAMP system, thanks to its “adaptivity”, is able to achieve...

Antenna Design for Diversity and MIMO Application

DEFF Research Database (Denmark)

Ying, Zhinong; Chiu, Chi-Yuk; Zhao, Kun

2015-01-01

Recently, multiple-input multiple-output (MIMO) technology and diversity have attracted much attention both in industry and academia due to high data rate and high spectrum efficiency. By increasing the number of antennas at the transmitter and/or the receiver side of the wireless link, the diver...

On the Secrecy Capacity of the Multiple-Antenna Wiretap Channel with Limited CSI Feedback

KAUST Repository

Hyadi, Amal; Rezki, Zouheir; Alouini, Mohamed-Slim

2015-01-01

We study the ergodic secrecy capacity of a block fading wiretap channel when there are multiple antennas at the transmitter, the legitimate receiver and the eavesdropper. We consider that the receivers are aware of their respective channel matrices while the transmitter is only provided by a B-bits feedback of the main channel state information. The feedback bits are sent by the legitimate receiver, at the beginning of each fading block, over an error free public link with limited capacity. Assuming an average transmit power constraint, we provide an upper and a lower bounds on the ergodic secrecy capacity. Then, we present a framework to design the optimal codebooks for feedback and transmission. In addition, we show that the proposed lower and upper bounds coincide asymptotically as the capacity of the feedback link becomes large; hence, fully characterizing the secrecy capacity in this case.

On the Secrecy Capacity of the Multiple-Antenna Wiretap Channel with Limited CSI Feedback

KAUST Repository

Hyadi, Amal

2015-12-01

We study the ergodic secrecy capacity of a block fading wiretap channel when there are multiple antennas at the transmitter, the legitimate receiver and the eavesdropper. We consider that the receivers are aware of their respective channel matrices while the transmitter is only provided by a B-bits feedback of the main channel state information. The feedback bits are sent by the legitimate receiver, at the beginning of each fading block, over an error free public link with limited capacity. Assuming an average transmit power constraint, we provide an upper and a lower bounds on the ergodic secrecy capacity. Then, we present a framework to design the optimal codebooks for feedback and transmission. In addition, we show that the proposed lower and upper bounds coincide asymptotically as the capacity of the feedback link becomes large; hence, fully characterizing the secrecy capacity in this case.

Transmit selection for imperfect threshold-based receive MRC in Rayleigh fading channels

KAUST Repository

Radaydeh, Redha Mahmoud Mesleh

2010-01-01

The performance of multiple-antenna diversity systems in which the receiver combines signal replicas per thresholdbased maximal ratio combining (MRC) and the transmitter uses only a single antenna according to receive combined signal strength is studied. The impact of imperfect channel estimation is considered when the received signal replicas undergo independent and flat multipath fading. The analysis is applicable for arbitrary transmit antenna selection when the multiple-antenna channels experience identically distributed and non-identically distributed Rayleigh fading conditions. New closed-form expressions for the combined SNR statistics and some performance measures are presented. The system models adopted herein and the presented analytical results can be used to study the performance of different system architectures under various channel conditions when the implementation complexity is of interest. © 2009 IEEE.

Reduced Complexity Detection in MIMO Systems with SC-FDE Modulations and Iterative DFE Receivers

Directory of Open Access Journals (Sweden)

Filipe Casal Ribeiro

2018-04-01

Full Text Available This paper considers a Multiple-Input Multiple-Output (MIMO system with P transmitting and R receiving antennas and different overall noise characteristics on the different receiver antennas (e.g., due to nonlinear effects at the receiver side. Each communication link employs a Single-Carrier with Frequency-Domain Equalization (SC-FDE modulation scheme, and the receiver is based on robust iterative frequency-domain multi-user detectors based on the Iterative Block Decision Feedback Equalization (IB-DFE concept. We present low complexity efficient receivers that can employ low resolution Analog-to-Digital Converters (ADCs and require the inversion of matrices with reduced dimension when the number of receive antennas is larger than the number of independent data streams. The advantages of the proposed techniques are particularly high for highly unbalanced MIMO systems, such as in the uplink of Base Station (BS cooperation systems that aim for Single-Frequency Network (SFN operation or massive MIMO systems with much more antennas at the receiver side.

Channel Estimation and Optimal Power Allocation for a Multiple-Antenna OFDM System

Directory of Open Access Journals (Sweden)

Yao Kung

2002-01-01

Full Text Available We propose combining channel estimation and optimal power allocation approaches for a multiple-antenna orthogonal frequency division multiplexing (OFDM system in high-speed transmission applications. We develop a least-square channel estimation approach, derive the performance bound of the estimator, and investigate the optimal training sequences for initial channel acquisition. Based on the channel estimates, the optimal power allocation solution which maximizes the bandwidth efficiency is derived under power and quality of service (Qos (symbol error rate constraints. It is shown that combining channel tracking and adaptive power allocation can dramatically enhance the outage capacity of an OFDM multiple-antenna system when severing fading occurs.

Multibeam smart antenna field trial experiments in mobile radio environments

Science.gov (United States)

Perini, Patrick

1996-01-01

Several types of high gain multibeam antennas were tested and compared to traditional sector and omni antennas in various mobile radio environments. A vehicle equipped with a mobile transmitter drove in several mobile radio environments while the received signal strength (RSS) was recorded on multiple antenna channels attached to multibeam, sector and omni directional antennas. The RSS data recorded included the fast (rayleigh) fading and was averaged into local means based on the mobile's position/speed. Description of the experiment and analysis of the gain improvement, average RSS, diversity gain are presented.

Improvements to Host Country Radio Astronomy at Robledo: Another antenna, a new receiver, a new backend

Science.gov (United States)

Rizzo, J. R.; García-Miró, G.

2013-05-01

NASA hosts three complexes worldwide built for spacecraft tracking, whose sensitive antennas are suitable for radio astronomy. Since more than a decade, INTA has managed guaranteed Spanish time at the complex located in Robledo de Chavela, in the frame of the Host Country Radio Astronomy (HCRA) program. Until now, the vast majority of the scientific results were achieved using a K-band (18 to 26 GHz) receiver, attached to the 70m antenna, and a narrow-band autocorrelator. In the recent years, we have undertaken two large instrumental projects: (1) the incorporation of a second antenna (34m in diameter), working in Q-band (38 to 50 GHz); and (2) the design and construction of a wideband backend, which may operate with both the Q- and K-band receivers, providing instantaneous bandwidths from 100 MHz to 6 GHz, and resolutions from 6 to 200 kHz. The new wideband backend is expanding the HCRA possibilities due its bandwidth, versatility, spectral resolution and stability of the baselines. Its IF processor splits each of the two circular-polarization signals, and downconverts them to four base-band channels, 1.5 GHz width. Two different frequencies may be tuned independently. Digitalisation is done through FPGA-based FFT spectrometers, which may be independently configured. Once end-to-end assembled, the commissioning of the new backend was done using the 34m antenna in Q-band. We report the main characteristics of both the antenna recently incorporated to HCRA, and the wideband backend.

Secure Multiple-Antenna Block-Fading Wiretap Channels with Limited CSI Feedback

KAUST Repository

Hyadi, Amal

2017-07-18

In this paper, we investigate the ergodic secrecy capacity of a block-fading wiretap channel with limited channel knowledge at the transmitter. We consider that the legitimate receiver, the eavesdropper and the transmitter are equipped with multiple antennas and that the receiving nodes are aware of their respective channel matrices. The transmitter, on the other hand, is only provided by a B-bit feedback of the main channel state information. The feedback bits are sent by the legitimate receiver, at the beginning of each fading block, over an error-free public link with limited capacity. The statistics of the main and the eavesdropper channel state information are known at all nodes. Assuming an average transmit power constraint, we establish upper and lower bounds on the ergodic secrecy capacity. Then, we present a framework to design the optimal codebooks for feedback and transmission. In addition, we show that the proposed lower and upper bounds coincide asymptotically as the capacity of the feedback link becomes large, i.e. $B \\ ightarrow \\\\infty$ ; hence, fully characterizing the ergodic secrecy capacity in this case. Besides, we analyze the asymptotic behavior of the presented secrecy rates, at high Signal-to-Noise Ratio (SNR), and evaluate the gap between the bounds.

Secure Multiple-Antenna Block-Fading Wiretap Channels with Limited CSI Feedback

KAUST Repository

Hyadi, Amal; Rezki, Zouheir; Alouini, Mohamed-Slim

2017-01-01

In this paper, we investigate the ergodic secrecy capacity of a block-fading wiretap channel with limited channel knowledge at the transmitter. We consider that the legitimate receiver, the eavesdropper and the transmitter are equipped with multiple antennas and that the receiving nodes are aware of their respective channel matrices. The transmitter, on the other hand, is only provided by a B-bit feedback of the main channel state information. The feedback bits are sent by the legitimate receiver, at the beginning of each fading block, over an error-free public link with limited capacity. The statistics of the main and the eavesdropper channel state information are known at all nodes. Assuming an average transmit power constraint, we establish upper and lower bounds on the ergodic secrecy capacity. Then, we present a framework to design the optimal codebooks for feedback and transmission. In addition, we show that the proposed lower and upper bounds coincide asymptotically as the capacity of the feedback link becomes large, i.e. $B \\rightarrow \\infty$ ; hence, fully characterizing the ergodic secrecy capacity in this case. Besides, we analyze the asymptotic behavior of the presented secrecy rates, at high Signal-to-Noise Ratio (SNR), and evaluate the gap between the bounds.

Radio antennas

Science.gov (United States)

Gibson, S. W.

This book is concerned with providing an explanation of the function of an antenna without delving too deeply into the mathematics or theory. The characteristics of an antenna are examined, taking into account aspects of antenna radiation, wave motion on the antenna, resistance in the antenna, impedance, the resonant antenna, the effect of the ground, polarization, radiation patterns, coupling effects between antenna elements, and receiving vs. transmitting. Aspects of propagation are considered along with the types of antennas, transmission lines, matching devices, questions of antenna design, antennas for the lower frequency bands, antennas for more than one band, limited space antennas, VHF antennas, and antennas for 20, 15, and 10 meters. Attention is given to devices for measuring antenna parameters, approaches for evaluating the antenna, questions of safety, and legal aspects.

A Modal Approach to Compact MIMO Antenna Design

Science.gov (United States)

Yang, Binbin

MIMO (Multiple-Input Multiple-Output) technology offers new possibilities for wireless communication through transmission over multiple spatial channels, and enables linear increases in spectral efficiency as the number of the transmitting and receiving antennas increases. However, the physical implementation of such systems in compact devices encounters many physical constraints mainly from the design of multi-antennas. First, an antenna's bandwidth decreases dramatically as its electrical size reduces, a fact known as antenna Q limit; secondly, multiple antennas closely spaced tend to couple with each other, undermining MIMO performance. Though different MIMO antenna designs have been proposed in the literature, there is still a lack of a systematic design methodology and knowledge of performance limits. In this dissertation, we employ characteristic mode theory (CMT) as a powerful tool for MIMO antenna analysis and design. CMT allows us to examine each physical mode of the antenna aperture, and to access its many physical parameters without even exciting the antenna. For the first time, we propose efficient circuit models for MIMO antennas of arbitrary geometry using this modal decomposition technique. Those circuit models demonstrate the powerful physical insight of CMT for MIMO antenna modeling, and simplify MIMO antenna design problem to just the design of specific antenna structural modes and a modal feed network, making possible the separate design of antenna aperture and feeds. We therefore develop a feed-independent shape synthesis technique for optimization of broadband multi-mode apertures. Combining the shape synthesis and circuit modeling techniques for MIMO antennas, we propose a shape-first feed-next design methodology for MIMO antennas, and designed and fabricated two planar MIMO antennas, each occupying an aperture much smaller than the regular size of lambda/2 x lambda/2. Facilitated by the newly developed source formulation for antenna stored

On the performance of spectrum sharing systems with multiple antennas

KAUST Repository

Yang, Liang

2012-01-01

In this paper, we study the capacity of spectrum sharing (SS) multiple-input multiple-output (MIMO) systems over Rayleigh fading channels. More specifically, we present closed-form capacity formulas for such systems with and without optimal power and rate adaptation. A lower bound on the capacity is also derived to characterize the scaling law of the capacity. Results show that increasing the number of antennas has a negative effect on the system capacity in the low signal-to-noise (SNR) regime and the scaling law at high SNR is similar to the conventional MIMO systems. In addition, a lower bound on the capacity of the SS keyhole MIMO channels is analyzed. We also present a capacity analysis of SS MIMO maximal ratio combining (MRC) systems and the results show that the capacity of such systems always decreases with the increase of the number of antennas. Numerical results are finally given to illustrate our analysis. © 2012 ICST.

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.

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

KAUST Repository

Benkhelifa, Fatma; Alouini, Mohamed-Slim

2017-01-01

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.

Broadband Circularly Polarized Slot Antenna Loaded by a Multiple-Circular-Sector Patch.

Science.gov (United States)

Trinh-Van, Son; Yang, Youngoo; Lee, Kang-Yoon; Hwang, Keum Cheol

2018-05-15

In this paper, a microstrip-fed broadband circularly polarized (CP) slot antenna is presented. CP operation can be attained simply by embedding an S-shaped strip. By loading with a multiple-circular-sector patch, which consists of 12 circular-sector patches with identical central angles of 30° and different radii, the 3 dB axial ratio (AR) bandwidth is significantly broadened. To validate the performance of the proposed antenna, an antenna prototype is fabricated and tested. The fabricated antenna is 54 mm × 54 mm × 0.8 mm in size. The measured -10 dB reflection and 3 dB AR bandwidths are 81.06% (1.68⁻3.97 GHz) and 70.55% (1.89⁻3.95 GHz), respectively. Within the 3 dB AR bandwidth, the measured peak gain is 3.81 dBic. Reasonable agreement is also obtained between the measured and simulated results.

Integrated reconfigurable multiple-input–multiple-output antenna system with an ultra-wideband sensing antenna for cognitive radio platforms

KAUST Repository

Hussain, Rifaqat; Sharawi, Mohammad S.

2015-01-01

. The developed model can be used as a complete antenna platform for cognitive radio applications. The antenna system is developed on a single substrate area of dimensions 65 × 120 mm². The proposed sensing antenna is used to cover a wide range

Compliance boundaries for multiple-frequency base station antennas in three directions.

Science.gov (United States)

Thielens, Arno; Vermeeren, Günter; Kurup, Divya; Joseph, Wout; Martens, Luc

2013-09-01

In this article, compliance boundaries and allowed output powers are determined for the front, back, and side of multiple-frequency base station antennas, based on the root-mean-squared electric field, the whole-body averaged specific absorption rate (SAR), and the 10 g averaged SAR in both the limbs and the head and trunk. For this purpose, the basic restrictions and reference levels defined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) for both the general public and occupational exposure are used. The antennas are designed for Global System for Mobile Communications around 900 MHz (GSM900), GSM1800, High Speed Packet Access (HSPA), and Long Term Evolution (LTE), and are operated with output powers at the individual frequencies up to 300 W. The compliance boundaries are estimated using finite-difference time-domain simulations with the Virtual Family Male and have been determined for three directions with respect to the antennas for 800, 900, 1800, and 2600 MHz. The reference levels are not always conservative when the radiating part of the antenna is small compared to the length of the body. Combined compliance distances, which ensure compliance with all reference levels and basic restrictions, have also been determined for each frequency. A method to determine a conservative estimation of compliance boundaries for multiple-frequency (cumulative) exposure is introduced. Using the errors on the estimated allowed powers, an uncertainty analysis is carried out for the compliance distances. Uncertainties on the compliance distances are found to be smaller than 122%. Copyright © 2013 Wiley Periodicals, Inc.

FPGA-Based Communications Receivers for Smart Antenna Array Embedded Systems

Directory of Open Access Journals (Sweden)

Millar James

2006-01-01

Full Text Available Field-programmable gate arrays (FPGAs are drawing ever increasing interest from designers of embedded wireless communications systems. They outpace digital signal processors (DSPs, through hardware execution of a wide range of parallelizable communications transceiver algorithms, at a fraction of the design and implementation effort and cost required for application-specific integrated circuits (ASICs. In our study, we employ an Altera Stratix FPGA development board, along with the DSP Builder software tool which acts as a high-level interface to the powerful Quartus II environment. We compare single- and multibranch FPGA-based receiver designs in terms of error rate performance and power consumption. We exploit FPGA operational flexibility and algorithm parallelism to design eigenmode-monitoring receivers that can adapt to variations in wireless channel statistics, for high-performing, inexpensive, smart antenna array embedded systems.

FPGA-Based Communications Receivers for Smart Antenna Array Embedded Systems

Directory of Open Access Journals (Sweden)

James Millar

2006-10-01

Full Text Available Field-programmable gate arrays (FPGAs are drawing ever increasing interest from designers of embedded wireless communications systems. They outpace digital signal processors (DSPs, through hardware execution of a wide range of parallelizable communications transceiver algorithms, at a fraction of the design and implementation effort and cost required for application-specific integrated circuits (ASICs. In our study, we employ an Altera Stratix FPGA development board, along with the DSP Builder software tool which acts as a high-level interface to the powerful Quartus II environment. We compare single- and multibranch FPGA-based receiver designs in terms of error rate performance and power consumption. We exploit FPGA operational flexibility and algorithm parallelism to design eigenmode-monitoring receivers that can adapt to variations in wireless channel statistics, for high-performing, inexpensive, smart antenna array embedded systems.

Tracking Performance of Upgraded "Polished Panel" Optical Receiver on NASA's 34 Meter Research Antenna

Science.gov (United States)

Vilnrotter, Victor

2013-01-01

There has been considerable interest in developing and demonstrating a hybrid "polished panel" optical receiver concept that would replace the microwave panels on the Deep Space Network's (DSN) 34 meter antennas with highly polished aluminum panels, thus enabling simultaneous opticaland microwave reception. A test setup has been installed on the 34 meter research antenna at DSS-13 (Deep Space Station 13) at NASA's Goldstone Deep Space Communications Complex in California in order to assess the feasibility of this concept. Here we describe the results of a recent effort todramatically reduce the dimensions of the point-spread function (PSF) generated by a custom polished panel, thus enabling improved optical communications performance. The latest results are compared to the previous configuration in terms of quantifiable PSF improvement. In addition, the performance of acquisition and tracking algorithms designed specifically for the polished panel PSF are evaluated and compared, based on data obtained from real-time tracking of planets and bright stars with the 34 meter research antenna at DSS-13.

Simulation of a ring resonator-based optical beamformer system for phased array receive antennas

NARCIS (Netherlands)

Tijmes, M.R.; Meijerink, Arjan; Roeloffzen, C.G.H.; Bentum, Marinus Jan

2009-01-01

A new simulator tool is described that can be used in the field of RF photonics. It has been developed on the basis of a broadband, continuously tunable optical beamformer system for phased array receive antennas. The application that is considered in this paper is airborne satellite reception of

New receiving line for the remote-steering antenna of the 140 GHz CTS diagnostics in the FTU Tokamak

Science.gov (United States)

D'Arcangelo, O.; Bin, W.; Bruschi, A.; Cappelli, M.; Fanale, F.; Gittini, G.; Pallotta, F.; Rocchi, G.; Tudisco, O.; Garavaglia, S.; Granucci, G.; Moro, A.; Tuccillo, A. A.

2018-01-01

A new receiving antenna for collecting signals of the Collective Thomson Scattering (CTS) diagnostics in FTU Tokamak has been recently installed. The squared corrugated section and the precisely defined length make it possible to receive from different directions by remotely steering the receiving mirrors. This type of Remote-Steering (RS) antennas, being studied on FTU for the DEMO Electron Cyclotron Heating (ECH) system launch, is already installed on the W7- X stellarator and will be tested in the next campaign. The transmission of the signal from the antenna in the tokamak hall to the CTS diagnostics hall will be mainly realized by means of oversized circular corrugated waveguides carrying the hybrid HE11 (quasi-gaussian) waveguide mode, with inclusion of a special smooth-waveguide section and a short run of reduced-size square-corrugated waveguide through the tokamak bio-shield. The coupling between different waveguide types is made with ellipsoidal focusing mirrors, using quasi-optical matching formulas between the gaussian-shaped beams in input and output to the waveguides. In this work, after a complete study of feasibility of the overall line, a design for the receiving line will be proposed, in order to realize an executive layout to be used as a guideline for the commissioning phase.

2-D Fractal Wire Antenna Design and Performance

Science.gov (United States)

Tebbens, S. F.; Barton, C. C.; Peterman, D. J.; Ewing, J. J.; Abbott, C. S.; Rizki, M. M.

2017-12-01

A 2-D fractal wire antenna uses a fractal (self-similar) pattern to increase its length by iteration and can receive or transmit electromagnetic radiation. 2-D fractals are shapes that, at their mathematical limit (of infinite iterations) have an infinite length. The fractal dimension describes the degree of space filling. A fundamental property of fractal antennas lies in iteration (repetition) of a fractal pattern over a range of length scales. Iteration produces fractal antennas that can be very compact, wideband and multiband. As the number of iterations increases, the antenna tends to have additional frequencies that minimize far field return loss. This differs from traditional antenna designs in that a single fractal antenna can operate well at multiple frequencies. We have created a MATLAB code to generate deterministic and stochastic modes of fractal wire antennas with a range of fractal dimensions between 1 and 2. Variation in fractal dimension, stochasticity, and number of iterations have been computationally tested using COMSOL Multiphysics software to determine their effect on antenna performance.

Transmit Antenna Selection for Multi-User Underlay Cognitive Transmission with Zero-Forcing Beamforming

KAUST Repository

Hanif, Muhammad; Yang, Hong-Chuan; Alouini, Mohamed-Slim

2017-01-01

We present a transmit antenna subset selection scheme for an underlay cognitive system serving multiple secondary receivers. The secondary system employs zero-forcing beamforming to nullify the interference to multiple primary users and eliminate

On the performance of dual-hop systems with multiple antennas: Effects of spatial correlation, keyhole, and co-channel interference

KAUST Repository

Yang, Liang

2012-12-01

In this paper, taking into account realistic propagation conditions, namely, spatial correlation, keyhole channels, and unequal-power co-channel interference, we investigate the performance of a wireless relay network where all the nodes are equipped with multiple antennas. Considering channel state information assisted amplify-and-forward protocol, we present analytical expressions for the symbol error rate (SER) and outage probability. More specifically, we first derive the SER expressions of a relay system with orthogonal space-time block coding (OSTBC) over correlated/keyhole fading channels. We also analyze the outage probability of interference corrupted relay systems with maximal ratio combing (MRC) at the receiver as well as multiple-input multiple-output MRC (MIMO MRC). Numerical results are given to illustrate and verify the analytical results. © 2012 IEEE.

On the performance of dual-hop systems with multiple antennas: Effects of spatial correlation, keyhole, and co-channel interference

KAUST Repository

Yang, Liang; Alouini, Mohamed-Slim; Qaraqe, Khalid A.; Liu, Weiping

2012-01-01

In this paper, taking into account realistic propagation conditions, namely, spatial correlation, keyhole channels, and unequal-power co-channel interference, we investigate the performance of a wireless relay network where all the nodes are equipped with multiple antennas. Considering channel state information assisted amplify-and-forward protocol, we present analytical expressions for the symbol error rate (SER) and outage probability. More specifically, we first derive the SER expressions of a relay system with orthogonal space-time block coding (OSTBC) over correlated/keyhole fading channels. We also analyze the outage probability of interference corrupted relay systems with maximal ratio combing (MRC) at the receiver as well as multiple-input multiple-output MRC (MIMO MRC). Numerical results are given to illustrate and verify the analytical results. © 2012 IEEE.

A Dual-Band Multiple Input Multiple Output Frequency Agile Antenna for GPSL1/Wi-Fi/WLAN2400/LTE Applications

Directory of Open Access Journals (Sweden)

Sajid Aqeel

2016-01-01

Full Text Available A novel dual-band, single element multiple input multiple output (MIMO dielectric resonator antenna (DRA with a modest frequency tuning ability is presented in this communication. The proposed antenna operates at GPS L1/Bluetooth/Wi-Fi/LTE2500/WLAN2400 frequency bands. A single dielectric resonator element is fed by two coaxial probes to excite the orthogonal modes. A couple of slots are introduced on the ground plane to improve the isolation between antenna ports. The slots also serve the purpose of reconfiguration in the lower band on placement of switches at optimized locations. The measured impedance bandwidth is 5.16% (1.41–1.49 GHz in the lower band and 26% (2.2–2.85 GHz in the higher band. The lower band reconfigures with an impedance bandwidth of 6.5% (1.55–1.65 GHz when PIN diodes are switched ON. The gain, efficiency, correlation coefficient, and diversity gain of the MIMO DRA are presented with a close agreement between simulated and measured results.

A Single Atom Antenna

International Nuclear Information System (INIS)

Trinter, Florian; Williams, Joshua B; Weller, Miriam; Waitz, Markus; Pitzer, Martin; Voigtsberger, Jörg; Schober, Carl; Kastirke, Gregor; Müller, Christian; Goihl, Christoph; Burzynski, Phillip; Wiegandt, Florian; Wallauer, Robert; Kalinin, Anton; Schmidt, Lothar Ph H; Schöffler, Markus S; Jahnke, Till; Dörner, Reinhard; Chiang, Ying-Chih; Gokhberg, Kirill

2015-01-01

Here we demonstrate the smallest possible implementation of an antenna-receiver complex which consists of a single (helium) atom acting as the antenna and a second (neon) atom acting as a receiver. (paper)

Compact printed high rejection triple band-notch UWB antenna with multiple wireless applications

Directory of Open Access Journals (Sweden)

Manish Sharma

2016-09-01

Full Text Available In this paper, small printed urn-shape triple notch ultra-wideband (UWB monopole antenna with diverse wireless applications is presented. Notch bands include WiMAX (IEEE802.16 3.30–3.80 GHz, WLAN IEEE802.11a/h/j/n (5.15–5.35 GHz, 5.25–5.35 GHz, 5.47–5.725 GHz, 5.725–5.825 GHz, and X-band downlink satellite system (7.25–7.75 GHz and other multiple wireless services as close range radar (8–12 GHz in X-band & satellite communication (12–18 GHz in Ku-band. By including T-shape stub and etching two C-shaped slots on the radiating patch, triple band-notch function is obtained with measured high band rejection (VSWR = 16.54 at 3.60 GHz, VSWR = 22.35 at 5.64 GHz and VSWR = 6.38 at 7.64 GHz and covers a wide useable fractional bandwidth of 154.56% (2.49–19.41 GHz. In short the antenna offers triple band-notch UWB systems as a compact multifunctional antenna to reduce the number of antennas installed in wireless devices for accessing multiple wireless networks with wide radiation pattern.

Joint switched multi-spectrum and transmit antenna diversity for spectrum sharing systems

KAUST Repository

Sayed, Mostafa M.

2013-10-01

In spectrum sharing systems, a secondary user (SU) is allowed to share the spectrum with a primary (licensed) network under the condition that the interference observed at the receivers of the primary users (PU-Rxs) is below a predetermined level. In this paper, we consider a secondary network comprised of a secondary transmitter (SU-Tx) equipped with multiple antennas and a single-antenna secondary receiver (SU-Rx) sharing the same spectrum with multiple primary users (PUs), each with a distinct spectrum. We develop transmit antenna diversity schemes at the SU-Tx that exploit the multi-spectrum diversity provided by the existence of multiple PUs so as to optimize the signal-to-noise ratio (SNR) at the SU-Rx. In particular, assuming bounded transmit power at the SU-Tx, we develop switched selection schemes that select the primary spectrum and the SU-Tx transmit antenna that maintain the SNR at the SU-Rx above a specific threshold. Assuming Rayleigh fading channels and binary phase-shift keying (BPSK) transmission, we derive the average bit-error-rate (BER) and average feedback load expressions for the proposed schemes. For the sake of comparison, we also derive a BER expression for the optimal selection scheme that selects the best antenna/spectrum pair that maximizes the SNR at the SU-Rx, in exchange of high feedback load and switching complexity. Finally, we show that our analytical results are in perfect agreement with the simulation results. © 2013 IEEE.

GPS antenna designs

Science.gov (United States)

Laube, Samuel J. P.

1987-05-01

Application of the current GPS NAVSTAR system to civilian service requires that a right hand, circularly polarized, -160 dBW spread spectrum signal be received from an orbiting satellite, where the antenna environment is also moving. This presents a design challenge when inexpensive antennas are desired. The intent of this survey is to provide information on the antennas mentioned and to construct and test prototypes to determine whether the choice made by the industry, the quadrifilar helix, is the best. The helix antenna is currently the low cost standard for GPS. Prototype versions were constructed using 12 gauge wire and subminiature coaxial hardline. The constructed antennas were tested using a signal generator and a reference turnstile. A spectrum analyzer was used to measure the level of the received signal.

PhantomNet: Exploring Optimal Multicellular Multiple Antenna Systems

Directory of Open Access Journals (Sweden)

Foschini Gerard J

2004-01-01

Full Text Available We present a network framework for evaluating the theoretical performance limits of wireless data communication. We address the problem of providing the best possible service to new users joining the system without affecting existing users. Since, interference-wise, new users are required to be invisible to existing users, the network is dubbed PhantomNet. The novelty is the generality obtained in this context. Namely, we can deal with multiple users, multiple antennas, and multiple cells on both the uplink and the downlink. The solution for the uplink is effectively the same as for a single cell system since all the base stations (BSs simply amount to one composite BS with centralized processing. The optimum strategy, following directly from known results, is successive decoding (SD, where the new user is decoded before the existing users so that the new users' signal can be subtracted out to meet its invisibility requirement. Only the BS needs to modify its decoding scheme in the handling of new users, since existing users continue to transmit their data exactly as they did before the new arrivals. The downlink, even with the BSs operating as one composite BS, is more problematic. With multiple antennas at each BS site, the optimal coding scheme and the capacity region for this channel are unsolved problems. SD and dirty paper (DP are two schemes previously reported to achieve capacity in special cases. For PhantomNet, we show that DP coding at the BS is equal to or better than SD. The new user is encoded before the existing users so that the interference caused by his signal to existing users is known to the transmitter. Thus the BS modifies its encoding scheme to accommodate new users so that existing users continue to operate as before: they achieve the same rates as before and they decode their signal in precisely the same way as before. The solutions for the uplink and the downlink are particularly interesting in the way they exhibit a

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.

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

KAUST Repository

Makki, Behrooz; Ide, Anatole; Svensson, Tommy; Eriksson, Thomas; Alouini, Mohamed-Slim

2016-01-01

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.

2-D Fractal Carpet Antenna Design and Performance

Science.gov (United States)

Barton, C. C.; Tebbens, S. F.; Ewing, J. J.; Peterman, D. J.; Rizki, M. M.

2017-12-01

A 2-D fractal carpet antenna uses a fractal (self-similar) pattern to increase its perimeter by iteration and can receive or transmit electromagnetic radiation within its perimeter-bounded surface area. 2-D fractals are shapes that, at their mathematical limit (infinite iterations) have an infinite perimeter bounding a finite surface area. The fractal dimension describes the degree of space filling and lacunarity which quantifies the size and spatial distribution of open space bounded by a fractal shape. A key aspect of fractal antennas lies in iteration (repetition) of a fractal pattern over a range of length scales. Iteration produces fractal antennas that are very compact, wideband and multiband. As the number of iterations increases, the antenna operates at higher and higher frequencies. Manifestly different from traditional antenna designs, a fractal antenna can operate at multiple frequencies simultaneously. We have created a MATLAB code to generate deterministic and stochastic modes of Sierpinski carpet fractal antennas with a range of fractal dimensions between 1 and 2. Variation in fractal dimension, stochasticity, number of iterations, and lacunarities have been computationally tested using COMSOL Multiphysics software to determine their effect on antenna performance

On the Required Number of Antennas in a Point-to-Point Large-but-Finite MIMO System: Outage-Limited Scenario

KAUST Repository

Makki, Behrooz

2016-03-22

This paper investigates the performance of the point-To-point multiple-input-multiple-output (MIMO) systems in the presence of a large but finite numbers of antennas at the transmitters and/or receivers. Considering the cases with and without hybrid automatic repeat request (HARQ) feedback, we determine the minimum numbers of the transmit/receive antennas, which are required to satisfy different outage probability constraints. Our results are obtained for different fading conditions and the effect of the power amplifiers efficiency/feedback error probability on the performance of the MIMO-HARQ systems is analyzed. Then, we use some recent results on the achievable rates of finite block-length codes, to analyze the effect of the codewords lengths on the system performance. Moreover, we derive closed-form expressions for the asymptotic performance of the MIMO-HARQ systems when the number of antennas increases. Our analytical and numerical results show that different outage requirements can be satisfied with relatively few transmit/receive antennas. © 1972-2012 IEEE.

Influence of Antenna Characteristics on Elevation Dependence of Building Penetration Loss for High Elevation Links

Directory of Open Access Journals (Sweden)

M. Kvicera

2012-12-01

Full Text Available Building penetration loss models presented in our previous paper [1] were valid for various scenarios, propagation conditions, frequency bands and hemispherical receiving antenna pointing towards zenith. These models had a significantly rising trend of penetration loss with increasing elevation angle of the link in common. In this paper we show that when working with non-isotropic terminal antennas, this trend relates primarily to the elevation trend of the corresponding reference level dependent on the receiving antenna radiation pattern. This is demonstrated by the results of single-input multiple-output (SIMO measurement trials performed at L-band in an office building and a brick building in the city of Prague. Further, based on the detailed analysis, a method to modify the elevation trend of a particular penetration loss model for different receiving antenna radiation patterns is derived and experimentally validated.

High-Performance Wireless via the Merger of CI Chip-Shaped DS-CDMA and Oscillating-Beam Smart Antenna Arrays

Directory of Open Access Journals (Sweden)

Nassar Carl R

2004-01-01

Full Text Available We introduce a novel merger of direct sequence code division multiple access (DS-CDMA and smart antenna arrays. With regard to the DS-CDMA scheme, we employ carrier interferometry DS-CDMA (CI/DS-CDMA, a novel implementation of DS-CDMA where chips are decomposable into narrowband frequency components. With regard to the antenna array, we deploy the oscillating-beam smart array. Here, applying proper time-varying phases to the array elements, we create small movement (oscillation in the antenna array's pattern, while steering the antenna pattern main lobe to the position of the intended user. The oscillating antenna pattern creates a time-varying channel with a controllable coherence time. This, in turn, provides transmit diversity in the form of a time diversity gain at the mobile receiver side. At the receiver, three stages of combining are available: combining time components of the received signal within symbol duration (each experiencing a different fade to enhance performance via time diversity; combining frequency components which make up the CI/DS-CDMA chip to enhance the performance via frequency diversity; and combining across chips to eliminate the interfering users on the system. Merging CI/DS-CDMA with the oscillating-beam smart antenna at the base station, we achieve very high capacity via the merger of SDMA (available through directionality of the antenna array and code division multiple access (inherent in CI/DS-CDMA, and very high performance via the construction of receivers that exploit both transmit diversity and frequency diversity. We present the performance gains of the proposed merger.

Extended Monopole antenna Array with individual Shield (EMAS) coil: An improved monopole antenna design for brain imaging at 7 tesla MRI.

Science.gov (United States)

Woo, Myung-Kyun; Hong, Suk-Min; Lee, Jongho; Kang, Chang-Ki; Park, Sung-Yeon; Son, Young-Don; Kim, Young-Bo; Cho, Zang-Hee

2016-06-01

To propose a new Extended Monopole antenna Array with individual Shields (EMAS) coil that improves the B1 field coverage and uniformity along the z-direction. To increase the spatial coverage of Monopole antenna Array (MA) coil, each monopole antenna was shielded and extended in length. Performance of this new coil, which is referred to as EMAS coil, was compared with the original MA coil and an Extended Monopole antenna Array coil with no shield (EMA). For comparison, flip angle, signal-to-noise ratio (SNR), and receive sensitivity maps were measured at multiple regions of interest (ROIs) in the brain. The EMAS coil demonstrated substantially larger flip angle and receive sensitivity than the MA and EMA coils in the inferior aspect of the brain. In the brainstem ROI, for example, the flip angle in the EMAS coil was increased by 45.5% (or 60.0%) and the receive sensitivity was increased by 26.9% (or 14.9%), resulting in an SNR gain of 84.8% (or 76.3%) when compared with the MA coil (or EMA). The EMAS coil provided 25.7% (or 24.4%) more uniform B1+ field distribution compared with the MA (or EMA) coil in sagittal. The EMAS coil successfully extended the imaging volume in lower part of the brain. Magn Reson Med 75:2566-2572, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Diversity and MIMO Performance Evaluation of Common Phase Center Multi Element Antenna Systems

Directory of Open Access Journals (Sweden)

V. Papamichael

2008-06-01

Full Text Available The diversity and Multiple Input Multiple Output (MIMO performance provided by common phase center multi element antenna (CPCMEA systems is evaluated using two practical methods which make use of the realized active element antenna patterns. These patterns include both the impact of the mutual coupling and the mismatch power loss at antenna ports. As a case study, two and four printed Inverted F Antenna (IFA systems are evaluated by means of Effective Diversity Gain (EDG and Capacity (C. EDG is measured in terms of the signal-to-noise ratio (SNR enhancement at a specific outage probability and in terms of the SNR reduction for achieving a desired average bit error rate (BER. The concept of receive antenna selection in MIMO systems is also investigated and the simulation results show a 43% improvement in the 1% outage C of a reconfigurable 2x2 MIMO system over a fixed 2x2 one.

Transmit Antenna Selection for Power Adaptive Underlay Cognitive Radio with Instantaneous Interference Constraint

KAUST Repository

Hanif, Muhammad

2017-03-31

The high hardware cost associated with multiple antennas at the secondary transmitter of an underlay cognitive radio (CR) can be reduced by antenna selection. This paper analyzes different power adaptive transmit antenna selection (TAS) schemes for an underlay CR, which ensure that the instantaneous interference caused by the secondary transmitter to the primary receiver is below a predetermined level. We consider the optimal continuous power adaptive TAS and present a low-complexity antenna and power level selection scheme, named sequential antenna and power level selection scheme (SAPS), for discrete power adaptation. Exact statistical characterizations of the signal-to-interference plus noise ratio at the secondary receiver are derived for the considered schemes. Based on the newly derived statistics, we prove that the considered schemes achieve the highest diversity order equaling the number of antennas at the secondary transmitter. Further, we also derive a closed-form expression of the ergodic capacity for the underlay CR with SAPS scheme. Finally, we show that the proposed scheme outperforms existing schemes in terms of ergodic capacity.

On the Ergodic Secret-Key Agreement over Spatially Correlated Multiple-Antenna Channels with Public Discussion

KAUST Repository

Zorgui, Marwen

2015-09-28

We consider secret-key agreement with public discussion over multiple-input multiple-output (MIMO) Rayleigh fast-fading channels under correlated environment. We assume that transmit, legitimate receiver and eavesdropper antennas are correlated. The legitimate receiver and the eavesdropper are assumed to have perfect channel knowledge while the transmitter has only knowledge of the correlation matrices. First, we derive the expression of the secret-key capacity under the considered setup. We prove that the optimal transmit strategy achieving the secret-key capacity consists in transmitting independent Gaussian signals along the eingenvectors of the transmit correlation matrix. The powers allocated to each channel mode are determined as the solution to a numerical optimization problem. A necessary and sufficient condition for beamforming (i.e., transmitting along the strongest channel mode) to be capacity-achieving is derived. Moreover, we analyze the impact of correlation matrices on the system performance. Finally, we study the system’s performance in the two extreme power regimes. In the high-power regime, we provide closed-form expressions of the gain/loss due to correlation. In the low signal-to-noise ratio (SNR) regime, we investigate the energy efficiency of the system by determining the minimum energy required for sharing a secret-key bit and the wideband slope while highlighting the impact of correlation matrices.

Information-Theoretic Limits on Broadband Multi-Antenna Systems in the Presence of Mutual Coupling

Science.gov (United States)

Taluja, Pawandeep Singh

2011-12-01

Multiple-input, multiple-output (MIMO) systems have received considerable attention over the last decade due to their ability to provide high throughputs and mitigate multipath fading effects. While most of these benefits are obtained for ideal arrays with large separation between the antennas, practical devices are often constrained in physical dimensions. With smaller inter-element spacings, signal correlation and mutual coupling between the antennas start to degrade the system performance, thereby limiting the deployment of a large number of antennas. Various studies have proposed transceiver designs based on optimal matching networks to compensate for this loss. However, such networks are considered impractical due to their multiport structure and sensitivity to the RF bandwidth of the system. In this dissertation, we investigate two aspects of compact transceiver design. First, we consider simpler architectures that exploit coupling between the antennas, and second, we establish information-theoretic limits of broadband communication systems with closely-spaced antennas. We begin with a receiver model of a diversity antenna selection system and propose novel strategies that make use of inactive elements by virtue of mutual coupling. We then examine the limits on the matching efficiency of a single antenna system using broadband matching theory. Next, we present an extension to this theory for coupled MIMO systems to elucidate the impact of coupling on the RF bandwidth of the system, and derive optimal transceiver designs. Lastly, we summarize the main findings of this dissertation and suggest open problems for future work.

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.

Performance Analysis of Receive Diversity in Wireless Sensor Networks over GBSBE Models

Science.gov (United States)

Goel, Shivali; Abawajy, Jemal H.; Kim, Tai-hoon

2010-01-01

Wireless sensor networks have attracted a lot of attention recently. In this paper, we develop a channel model based on the elliptical model for multipath components involving randomly placed scatterers in the scattering region with sensors deployed on a field. We verify that in a sensor network, the use of receive diversity techniques improves the performance of the system. Extensive performance analysis of the system is carried out for both single and multiple antennas with the applied receive diversity techniques. Performance analyses based on variations in receiver height, maximum multipath delay and transmit power have been performed considering different numbers of antenna elements present in the receiver array, Our results show that increasing the number of antenna elements for a wireless sensor network does indeed improve the BER rates that can be obtained. PMID:22163510

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

Determining of the phase centre of the real position of GPS receiver antenna

OpenAIRE

Eva Pisoňová; Jozef Ornth; Vladimír Sedlák

2007-01-01

By continued improvement of measurement methods producers of GPS (Global Positioning System) apparatus will be maybe once upon a time effective to minimize a difference of the phase centre from the geometrical one, because it is probably impossible to make the GPS receiver antenna with zero eccentricity of the phase centre. In the last analysis, we do not prevent from a manufacturing error by any way in eliminate of the possible measurement errors.In the paper there is presented the measureme...

An Optimal Design of Multiple Antenna Positions on Mobile Devices Based on Mutual Coupling Analysis

Directory of Open Access Journals (Sweden)

Peerapong Uthansakul

2011-01-01

Full Text Available The topic of practical implementation of multiple antenna systems for mobile communications has recently gained a lot of attention. Due to the area constraint on a mobile device, the problem of how to design such a system in order to achieve the best benefit is still a huge challenge. In this paper, genetic algorithm (GA is used to find the optimal antenna positions on a mobile device. Two cases of 3×3 and 4×4 MIMO systems are undertaken. The effect of mutual coupling based on Z-parameter is the main factor to determine the MIMO capacity concerning the objective function of GA search. The results confirm the success of the proposed method to design MIMO antenna positions on a mobile device. Moreover, this paper introduces the method to design the antenna positions for the condition of nondeterministic channel. The concern of channel variation has been included in the process of finding optimal MIMO antenna positions. The results suggest that the averaging position from all GA solutions according to all channel conditions provides the most acceptable benefit.

Performance Analysis of Receive Diversity in Wireless Sensor Networks over GBSBE Models

Directory of Open Access Journals (Sweden)

Tai-hoon Kim

2010-12-01

Full Text Available Wireless sensor networks have attracted a lot of attention recently. In this paper, we develop a channel model based on the elliptical model for multipath components involving randomly placed scatterers in the scattering region with sensors deployed on a field. We verify that in a sensor network, the use of receive diversity techniques improves the performance of the system. Extensive performance analysis of the system is carried out for both single and multiple antennas with the applied receive diversity techniques. Performance analyses based on variations in receiver height, maximum multipath delay and transmit power have been performed considering different numbers of antenna elements present in the receiver array, Our results show that increasing the number of antenna elements for a wireless sensor network does indeed improve the BER rates that can be obtained.

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.

On diversity performance of two-element coupling element based antenna structure for mobile terminal

DEFF Research Database (Denmark)

Al-Hadi, Azremi Abdullah; Toivanen, Juha; Laitinen, Tommi

2010-01-01

.1 and the diversity gain is equal to 10.2 dB at 99% reliability level using selection combining technique across simulation and both measurement methods. The measurement techniques are compared to show how accurately the diversity performance of a mobile terminal antenna can be estimated.......In wireless communication systems, multipath interference has a significant impact on system design and performance. Fast fading is caused by the coherent summation of one or more echoes from many reflection points reaching the receive antenna. Antenna diversity can be used to mitigate multipath...... fading. The main challenge of antenna diversity in practical application is the integration of multiple antennas on a small ground plane. Two-element antenna structure based on coupling element antenna concept for diversity application has been studied in previous work and it has shown to be feasible...

Impact of Mutual Coupling and Polarization of Antennas on BER Performances of Spatial Multiplexing MIMO Systems

Directory of Open Access Journals (Sweden)

Jianfeng Zheng

2012-01-01

Full Text Available This paper is aimed at studying the impacts of mutual coupling, matching networks, and polarization of antennas on performances of Multiple-Input Multiple-Output (MIMO systems employing Spatial Multiplexing (SM. In particular, the uncoded average Bit Error Rate (BER of MIMO systems is investigated. An accurate signal analysis framework based on circuit network parameters is presented to describe the transmit/receive characteristics of the matched/unmatched antenna array. The studied arrays consist of matched/unmatched compact copolarization and polarization diversity antenna array. Monte-Carlo numerical simulations are used to study the BER performances of the SM MIMO systems using maximum-likelihood and/or zero-forcing detection schemes. The simulation results demonstrate that the use of matching networks can improve the BER performance of SM MIMO systems significantly, and the BER performance deterioration due to antenna orientation randomness can be compensated by use of polarization diversity antenna arrays.

An adaptive Multiplicative Extened Kalman Filter for Attitude Estimation of Marine Satellite Tracking Antenna

DEFF Research Database (Denmark)

Wang, Yunlong; Soltani, Mohsen; Hussain, Dil muhammed Akbar

2016-01-01

, an adaptive Multiplicative Extended Kalman Filter (MEKF) for attitude estimation of Marine Satellite Tracking Antenna (MSTA) is presented with the measurement noise covariance matrix adjusted according to the norm of accelerometer measurements, which can significantly reduce the slamming influence from waves...

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.

GPS Antenna Data Needed : GPS Adjacent Band Compatibility Workshop Volpe Center, Cambridge MA

Science.gov (United States)

2014-09-18

Topics. 1. Technical Objective: Receiver Antenna Mask and Electronics Data. 2. Definition of Receiver Antenna Mask. 3. Use of Receiver Antenna Mask. 4. Approaches to Generate the Antenna Mask. 5. Request for Receiver Antenna Data. 6. Next Steps.

Wireless Communication with Multiple Antennas

Indian Academy of Sciences (India)

2013-07-05

Emre Telatar, “Capacity of Multi-antenna Gaussian Channels,” European. Transactions on Telecommunications, vol.10, No.6, pp.585-595, 1999. Similar diminishing-return behaviour with M fixed. B. Sundar Rajan (ECE). IASc Talk ...

Communications receivers principles and design

CERN Document Server

Rohde, Ulrich L; Zahnd, Hans

2017-01-01

This thoroughly updated guide offers comprehensive explanations of the science behind today’s radio receivers along with practical guidance on designing, constructing, and maintaining real-world communications systems. You will explore system planning, antennas and antenna coupling, amplifiers and gain control, filters, mixers, demodulation, digital communication, and the latest software defined radio (SDR) technology. Written by a team of telecommunication experts, Communications Receivers: Principles and Design, Fourth Edition, features technical illustrations, schematic diagrams, and detailed examples. Coverage includes: • Basic radio considerations • Radio receiver characteristics • Receiver system planning • Receiver implementation considerations • RF and baseband techniques for Software-Defined Radios • Transceiver SDR considerations • Antennas and antenna coupling • Mixers • Frequency sources and control • Ancillary receiver circuits • Performance measurement

MILA Antenna Control Unit Replacement Project

Science.gov (United States)

Bresette, Jeremy

2007-01-01

The Air to Ground Subsystem (AGS) Antenna Control Units at the MILA Ground Network Tracking Station are at end-of-life and are being replaced. AGS consists of two antennas at MILA (Quad-Helix and Teltrac). Software was taken from the existing Subsystem Controller and modified for the Antenna Control Unit (ACU). The software is capable of receiving and sending commands to and from the ACU. Moving the azimuth clockwise, counterclockwise, moving the elevation up or down, turning servo power on and off, and inputting azimuth and elevation angles are commands that the antenna can receive.

A dual-polarized broadband planar antenna and channelizing filter bank for millimeter wavelengths

Science.gov (United States)

O'Brient, Roger; Ade, Peter; Arnold, Kam; Edwards, Jennifer; Engargiola, Greg; Holzapfel, William L.; Lee, Adrian T.; Myers, Michael J.; Quealy, Erin; Rebeiz, Gabriel; Richards, Paul; Suzuki, Aritoki

2013-02-01

We describe the design, fabrication, and testing of a broadband log-periodic antenna coupled to multiple cryogenic bolometers. This detector architecture, optimized here for astrophysical observations, simultaneously receives two linear polarizations with two octaves of bandwidth at millimeter wavelengths. The broad bandwidth signal received by the antenna is divided into sub-bands with integrated in-line frequency-selective filters. We demonstrate two such filter banks: a diplexer with two sub-bands and a log-periodic channelizer with seven contiguous sub-bands. These detectors have receiver efficiencies of 20%-40% and percent level polarization isolation. Superconducting transition-edge sensor bolometers detect the power in each sub-band and polarization. We demonstrate circularly symmetric beam patterns, high polarization isolation, accurately positioned bands, and high optical efficiency. The pixel design is applicable to astronomical observations of intensity and polarization at millimeter through sub-millimeter wavelengths. As compared with an imaging array of pixels measuring only one band, simultaneous measurements of multiple bands in each pixel has the potential to result in a higher signal-to-noise measurement while also providing spectral information. This development facilitates compact systems with high mapping speeds for observations that require information in multiple frequency bands.

Antenna concepts for interstellar search systems

International Nuclear Information System (INIS)

Basler, R.P.; Johnson, G.L.; Vondrak, R.R.

1977-01-01

An evaluation is made of microwave receiving systems designed to search for signals from extraterrestrial intelligence. Specific design concepts are analyzed parametrically to determine whether the optimum antenna system location is on earth, in space, or on the moon. Parameters considered include the hypothesized number of transmitting civilizations, the number of stars that must be searched to give any desired probability of receiving a signal, the antenna collecting area, the search time, the search range, and the cost. This analysis suggests that search systems based on the moon are not cost-competitive, if the search is extended only a few hundred light years from the earth, a Cyclops-type array on earth may be the most cost-effective system, for a search extending to 500 light years or more, a substantial cost and search-time advantage can be achieved with a large spherical reflector in space with multiple feeds, radio frequency interference shields can be provided for space systems, and cost can range from a few hundred million to tens of billions of dollars, depending on the parameter values assumed

Phased array antenna control

Science.gov (United States)

Doland, G. D. (Inventor)

1978-01-01

Several new and useful improvements in steering and control of phased array antennas having a small number of elements, typically on the order of 5 to 17 elements are provided. Among the improvements are increasing the number of beam steering positions, reducing the possibility of phase transients in signals received or transmitted with the antennas, and increasing control and testing capacity with respect to the antennas.

Proactive Spectrum Sharing for SWIPT in MIMO Cognitive Radio Systems Using Antenna Switching Technique

KAUST Repository

Benkhelifa, Fatma

2017-04-24

In this paper, we consider the simultaneous wireless information and power transfer (SWIPT) for the spectrum sharing (SS) in a multiple-input multiple-output (MIMO) cognitive radio (CR) network. The secondary transmitter (ST) selects only one antenna which maximizes the received signal-to-noise ratio (SNR) at the secondary receiver (SR) and minimizes the interference induced at the primary receiver (PR). Moreover, PR is an energy harvesting (EH) node using the antenna switching (AS) which assigns a subset of its antennas to harvest the energy and assigns the rest to decode its information data. The objective of this work is to show that the SS is advantageous for both SR and PR sides and leads to a win-win situation. To illustrate the incentive of the SS in CR network, we evaluate the energy and data performance metrics in terms of the average harvested energy, the power outage, and the mutual outage probability (MOP) which declares a data outage event if the PR or SR is in an outage. We present some special cases and asymptotic results of the derived analytic results. Through the simulation results, we show the impact of various simulation parameters and the benefits due to the presence of ST.

Design and optimization of LTE 1800 MIMO antenna.

Science.gov (United States)

Wong, Huey Shin; Islam, Mohammad Tariqul; Kibria, Salehin

2014-01-01

A multiple input and multiple output (MIMO) antenna that comprises a printed microstrip antenna and a printed double-L sleeve monopole antenna for LTE 1800 wireless application is presented. The printed double-L sleeve monopole antenna is fed by a 50 ohm coplanar waveguide (CPW). A novel T-shaped microstrip feedline printed on the other side of the PCB is used to excite the waveguide's outer shell. Isolation characteristics better than -15 dB can be obtained for the proposed MIMO antenna. The proposed antenna can operate in LTE 1800 (1710 MHz-1880 MHz). This antenna exhibits omnidirectional characteristics. The efficiency of the antenna is greater than 70% and has high gain of 2.18 dBi.

MR-based conductivity imaging using multiple receiver coils.

Science.gov (United States)

Lee, Joonsung; Shin, Jaewook; Kim, Dong-Hyun

2016-08-01

To propose a signal combination method for MR-based tissue conductivity mapping using a standard clinical scanner with multiple receiver coils. The theory of the proposed method is presented with two practical approaches, a coil-specific approach and a subject-specific approach. Conductivity maps were reconstructed using the transceive phase of the combined signal. The sensitivities of the coefficients used for signal combination were analyzed and the method was compared with other signal combination methods. For validation, multiple receiver brain coils and multiple receiver breast coils were used in phantom, in vivo brain, and in vivo breast studies. The variation among the conductivity estimates was conductivity estimates. MR-based tissue conductivity mapping is feasible when using a standard clinical MR scanner with multiple receiver coils. The proposed method reduces systematic errors in phase-based conductivity mapping that can occur due to the inhomogeneous magnitude of the combined receive profile. Magn Reson Med 76:530-539, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Effective use of multibeam antenna and space-time multiple access technology in modern mobile communication systems

OpenAIRE

Moskalets, N. V.

2015-01-01

A possibility for efficient use of radio-frequency spectrum and of corresponding increase in productivity of mobile communication system with space-time multiple access obtained by use of multibeam antenna of base station is considered.

Novel ring resonator-based integrated photonic beamformer for broadband phased array receive antennas - part 1: design and performance analysis

NARCIS (Netherlands)

Meijerink, Arjan; Roeloffzen, C.G.H.; Meijerink, Roland; Zhuang, L.; Marpaung, D.A.I.; Bentum, Marinus Jan; Burla, M.; Verpoorte, Jaco; Jorna, Pieter; Huizinga, Adriaan; van Etten, Wim

2010-01-01

A novel optical beamformer concept is introduced that can be used for seamless control of the reception angle in broadband wireless receivers employing a large phased array antenna (PAA). The core of this beamformer is an optical beamforming network (OBFN), using ring resonator-based broadband

Optimization of Training Signal Transmission for Estimating MIMO Channel under Antenna Mutual Coupling Conditions

Directory of Open Access Journals (Sweden)

Xia Liu

2010-01-01

Full Text Available This paper reports investigations on the effect of antenna mutual coupling on performance of training-based Multiple-Input Multiple-Output (MIMO channel estimation. The influence of mutual coupling is assessed for two training-based channel estimation methods, Scaled Least Square (SLS and Minimum Mean Square Error (MMSE. It is shown that the accuracy of MIMO channel estimation is governed by the sum of eigenvalues of channel correlation matrix which in turn is influenced by the mutual coupling in transmitting and receiving array antennas. A water-filling-based procedure is proposed to optimize the training signal transmission to minimize the MIMO channel estimation errors.

Smart Antenna UKM Testbed for Digital Beamforming System

Directory of Open Access Journals (Sweden)

2009-03-01

Full Text Available A new design of smart antenna testbed developed at UKM for digital beamforming purpose is proposed. The smart antenna UKM testbed developed based on modular design employing two novel designs of L-probe fed inverted hybrid E-H (LIEH array antenna and software reconfigurable digital beamforming system (DBS. The antenna is developed based on using the novel LIEH microstrip patch element design arranged into 4×1 uniform linear array antenna. An interface board is designed to interface to the ADC board with the RF front-end receiver. The modular concept of the system provides the capability to test the antenna hardware, beamforming unit, and beamforming algorithm in an independent manner, thus allowing the smart antenna system to be developed and tested in parallel, hence reduces the design time. The DBS was developed using a high-performance TMS320C6711TM floating-point DSP board and a 4-channel RF front-end receiver developed in-house. An interface board is designed to interface to the ADC board with the RF front-end receiver. A four-element receiving array testbed at 1.88–2.22 GHz frequency is constructed, and digital beamforming on this testbed is successfully demonstrated.

A Compact Multiple Notched Ultra-Wide Band Antenna with an Analysis of the CSRR-TO-CSRR Coupling for Portable UWB Applications.

Science.gov (United States)

Rahman, MuhibUr; Ko, Dong-Sik; Park, Jung-Dong

2017-09-25

We present a compact ultra-wideband (UWB) antenna integrated with sharp notches with a detailed analysis of the mutual coupling of the multiple notch resonators. By utilizing complementary split ring resonators (CSRR) on the radiating semi-circular patch, we achieve the sharp notch-filtering of various bands within the UWB band without increasing the antenna size. The notched frequency bands include WiMAX, INSAT, and lower and upper WLAN. In order to estimate the frequency shifts of the notch due to the coupling of the nearby CSRRs, an analysis of the coupling among the multiple notch resonators is carried out and we construct the lumped-circuit equivalent model. The time domain analysis of the proposed antenna is performed to show its validity on the UWB application. The measured frequency response of the input port corresponds quite well with the calculations and simulations. The radiation pattern of the implemented quad-notched UWB antenna is nearly omnidirectional in the passband.

On the performance of arbitrary transmit selection for threshold-based receive MRC with and without co-channel interference

KAUST Repository

Radaydeh, Redha Mahmoud Mesleh

2011-11-01

The performance of multiple-antenna diversity systems in which the receiver combines signal replicas per threshold-based maximal ratio combining (MRC) and transmitter uses only a single antenna according to receive combined signal strength is studied. The impact of imperfect channel estimation and the effect of phase and time misalignments between desired and undesired signals are implicitly investigated. It is assumed that the desired signal replicas and interfering signals undergo statistically independent flat Rayleigh fading. The analysis is applicable for arbitrary transmit antenna selection, based either on receive combined signal-to-noise ratio (SNR) or receive combined signal-to-interference-plus-noise ratio (SINR). For the scenario of identical multiple-antenna channels, closed-form analytical results for the combined SNR statistics and some performance measures are first presented. The SNR-based and SINR-based selection algorithms are then employed to obtain expressions for the distribution of combined SINR and outage probability performance, which are applicable for different statistical models of interfering signals. The adopted system models herein as well as the analytical development add enhancements on many existing results, and can be used to study the performance of different architectures under various channel conditions when the implementation complexity is of interest. © 2011 IEEE.

On the performance of arbitrary transmit selection for threshold-based receive MRC with and without co-channel interference

KAUST Repository

Radaydeh, Redha Mahmoud Mesleh; Alouini, Mohamed-Slim

2011-01-01

The performance of multiple-antenna diversity systems in which the receiver combines signal replicas per threshold-based maximal ratio combining (MRC) and transmitter uses only a single antenna according to receive combined signal strength is studied. The impact of imperfect channel estimation and the effect of phase and time misalignments between desired and undesired signals are implicitly investigated. It is assumed that the desired signal replicas and interfering signals undergo statistically independent flat Rayleigh fading. The analysis is applicable for arbitrary transmit antenna selection, based either on receive combined signal-to-noise ratio (SNR) or receive combined signal-to-interference-plus-noise ratio (SINR). For the scenario of identical multiple-antenna channels, closed-form analytical results for the combined SNR statistics and some performance measures are first presented. The SNR-based and SINR-based selection algorithms are then employed to obtain expressions for the distribution of combined SINR and outage probability performance, which are applicable for different statistical models of interfering signals. The adopted system models herein as well as the analytical development add enhancements on many existing results, and can be used to study the performance of different architectures under various channel conditions when the implementation complexity is of interest. © 2011 IEEE.

Flight Performance Evaluation of Three GPS Receivers for Sounding Rocket Tracking

Science.gov (United States)

Bull, Barton; Diehl, James; Montenbruck, Oliver; Markgraf, Markus; Bauer, Frank (Technical Monitor)

2002-01-01

In preparation for the European Space Agency Maxus-4 mission, a sounding rocket test flight was carried out at Esrange, near Kiruna, Sweden on February 19, 2001 to validate existing ground facilities and range safety installations. Due to the absence of a dedicated scientific payload, the flight offered the opportunity to test multiple GPS receivers and assess their performance for the tracking of sounding rockets. The receivers included an Ashtech G12 HDMA receiver, a BAE (Canadian Marconi) Allstar receiver and a Mitel Orion receiver. All of them provide C/A code tracking on the L1 frequency to determine the user position and make use of Doppler measurements to derive the instantaneous velocity. Among the receivers, the G12 has been optimized for use under highly dynamic conditions and has earlier been flown successfully on NASA sounding rockets. The Allstar is representative of common single frequency receivers for terrestrial applications and received no particular modification, except for the disabling of the common altitude and velocity constraints that would otherwise inhibit its use for space application. The Orion receiver, finally, employs the same Mitel chipset as the Allstar, but has received various firmware modifications by DLR to safeguard it against signal losses and improve its tracking performance. While the two NASA receivers were driven by a common wrap-around antenna, the DLR experiment made use of a switchable antenna system comprising a helical antenna in the tip of the rocket and two blade antennas attached to the body of the vehicle. During the boost a peak acceleration of roughly l7g's was achieved which resulted in a velocity of about 1100 m/s at the end of the burn. At apogee, the rocket reached an altitude of over 80 km. A detailed analysis of the attained flight data is given together with a evaluation of different receiver designs and antenna concepts.

Antenna subset selection at multi-antenna relay with adaptive modulation

KAUST Repository

Choi, Seyeong

2011-06-01

In this paper, we proposed several antenna selection schemes for cooperative diversity systems with adaptive transmission. The proposed schemes were based on dual-hop relaying where a relay with multiple-antenna capabilities at reception and transmission is deployed between the source and the destination nodes. We analyzed the performance of the proposed schemes by quantifying the average spectral efficiency and the outage probability. We also investigated the trade-off of performance and complexity by comparing the average number of active antennas, path estimations, and signal-to-noise ratio comparisons of the different proposed schemes. Copyright © 2011 John Wiley & Sons, Ltd.

Antenna subset selection at multi-antenna relay with adaptive modulation

KAUST Repository

Choi, Seyeong; Hasna, Mazen Omar; Yang, Hongchuan; Alouini, Mohamed-Slim

2011-01-01

In this paper, we proposed several antenna selection schemes for cooperative diversity systems with adaptive transmission. The proposed schemes were based on dual-hop relaying where a relay with multiple-antenna capabilities at reception and transmission is deployed between the source and the destination nodes. We analyzed the performance of the proposed schemes by quantifying the average spectral efficiency and the outage probability. We also investigated the trade-off of performance and complexity by comparing the average number of active antennas, path estimations, and signal-to-noise ratio comparisons of the different proposed schemes. Copyright © 2011 John Wiley & Sons, Ltd.

Performance Evaluation of Irbene RT-16 Radio Telescope Receiving System

Directory of Open Access Journals (Sweden)

Bleiders M.

2017-12-01

Full Text Available In the present paper, recent measurement results of refurbished Irbene RT-16 radio telescope receiving system performance are presented. The aim of the research is to evaluate characteristics of RT-16, which will allow carrying out necessary amplitude calibration in both single dish and VLBI observations, to improve the performance of existing system as well as to monitor, control and compare performance if possible changes in the receiving system will occur in future. The evaluated receiving system is 16 m Cassegrain antenna equipped with a cryogenic receiver with frequency range from 4.5 to 8.8 GHz, which is divided into four sub-bands. Multiple calibration sessions have been carried out by observing stable astronomical sources with known flux density by using in-house made total power registration backend. First, pointing offset calibration has been carried out and pointing model coefficients calculated and applied. Then, amplitude calibration, namely antenna sensitivity, calibration diode equivalent flux density and gain curve measurements have been carried out by observing calibration sources at different antenna elevations at each of the receiver sub-bands. Beam patterns have also been evaluated at different frequency bands. As a whole, acquired data will serve as a reference point for comparison in future performance evaluation of RT-16.

Transmission Power and Antenna Allocation for Energy-Efficient RF Energy Harvesting Networks with Massive MIMO

Directory of Open Access Journals (Sweden)

Yu Min Hwang

2017-06-01

Full Text Available The optimum transmission strategy for maximizing energy efficiency (EE of a multi-user massive multiple-input multiple-output (MIMO system in radio frequency energy harvesting networks is investigated. We focus on dynamic time-switching (TS antennas, to avoid the practical problems of power-splitting antennas, such as complex architectures, power loss and signal distortion when splitting the power of the received signal into power for information decoding (ID and energy harvesting (EH. However, since a single TS antenna cannot serve ID and EH simultaneously, the MIMO system is considered in this paper. We thus formulate an EE optimization problem and propose an iterative algorithm as a tractable solution, including an antenna selection strategy to optimally switch each TS antenna between ID mode and EH mode using nonlinear fractional programming and the Lagrange dual method. Further, the problem is solved under practical constraints of maximum transmission power and outage probabilities for a minimum amount of harvested power and rate capacity for each user. Simulation results show that the proposed algorithm is more energy-efficient than that of baseline schemes, and demonstrates the trade-off between the required amount of harvested power and energy efficiency.

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

High Gain Advanced GPS Receiver

National Research Council Canada - National Science Library

Brown, Alison; Zhang, Gengsheng

2006-01-01

NAVSYS High Gain Advanced GPS Receiver (HAGR) uses a digital beam-steering antenna array to enable up to eight GPS satellites to be tracked, each with up to 10 dBi of additional antenna gain over a conventional receiver solution...

Full-duplex MIMO system based on antenna cancellation technique

DEFF Research Database (Denmark)

Foroozanfard, Ehsan; Franek, Ondrej; Tatomirescu, Alexandru

2014-01-01

The performance of an antenna cancellation technique for a multiple-input– multiple-output (MIMO) full-duplex system that is based on null-steering beamforming and antenna polarization diversity is investigated. A practical implementation of a symmetric antenna topology comprising three dual......-polarized patch antennas operating at 2.4 GHz is described. The measurement results show an average of 60 dB self-interference cancellation over 200 MHz bandwidth. Moreover, a decoupling level of up to 22 dB is achieved for MIMO multiplexing using antenna polarization diversity. The performance evaluation...

A tunable RF Front-End with Narrowband Antennas for Mobile Devices

DEFF Research Database (Denmark)

Bahramzy, Pevand; Olesen, Poul; Madsen, Peter

2015-01-01

desensitization due to the Tx signal. The filters and antennas demonstrate tunability across multiple bands. System validation is detailed for LTE band I. Frequency response, as well as linearity measurements of the complete Tx and Rx front-end chains, show that the system requirements are fulfilled.......In conventional full-duplex radio communication systems, the transmitter (Tx) is active at the same time as the receiver (Rx). The isolation between the Tx and the Rx is ensured by duplex filters. However, an increasing number of long-term evolution (LTE) bands crave multiband operation. Therefore......, a new front-end architecture, addressing the increasing number of LTE bands, as well as multiple standards, is presented. In such an architecture, the Tx and Rx chains are separated throughout the front-end. Addition of bands is solved by making the antennas and filters tunable. Banks of duplex filters...

Efficient Placement of Directional Antennas

Energy Technology Data Exchange (ETDEWEB)

Pan, Feng [Los Alamos National Laboratory; Kasiviswanathan, Shiva [Los Alamos National Laboratory

2010-09-20

Directional antenna is an technology for the proliferation of wireless networks. In centralized wireless network, wireless devices communicate through base stations. Directed antennas are placed on base stations and form a backbone of communication. The communication between base stations and wireless devices can be interfered due to a large number of wireless device. Methodically positioning and orienting directed antennas can help to reduce the interference while saving energy. An integer linear programming is developed for siting and directing antennas on multiple base stations, and this formulation can be extended to model non-overlapping channels. Through the integer programming formulation, optimal antenna positions can be used to analyze the performance of directed antennas with different parameters like the number base stations and the number of non-overlapping channels.

Experimental test for receiving X-Band data LAPAN-A3 Satellite with 5.4m antenna diameter

Science.gov (United States)

Dwi Harsono, Sonny; Hasbi, Wahyudi

2018-05-01

LAPAN-A3 / LAPAN-IPB Satellite launched on June 22, 2016 (03:56 UTC) as an experimental micro-satellite for remote sensing and monitoring of maritime traffic. The Satellite was launched as a secondary payload on ISRO Cartosat-2C as its main payload, the launch carried out at SDSC (Satish Dhawan Space Centre) in India using PSLV-C34 rocket launcher. The Satellite was in orbit polar sun-synchronous with a height of 505 km above sea level. It has an inclination angle of 97 degrees and heavy satellite 115 kg, with this orbit, the satellite will pass through Ground station 4 times (2 times during the day and two times at night) with a duration of the track at the time of the pass about 10-15 minutes. The Satellite payload carried 4 bands Line Scan Cameras and Digital Imager (SpaceCam). For main mission is the earth observation for food vegetables And as additional mission is carrying AIS (Automatic Identification System) receiver to monitor maritime traffic in the region of the poles, then Star Sensor made by LAPAN for qualifying room, then for scientific contained magnetometer sensor for monitoring the Earth's Magnetic field. The purpose of this scientific paper is to test the reception of data payloads of the LAPAN-A3 satellite on X-Band frequency of 8.2 GHz using a 5.4 M solid antenna Ground Stations LAPAN in Pare-Pare. The purpose of this experiment will tell us with 5.4 meter of diameter solid antenna is capable or not enough for HDRM receiver to lock a signal and produce the data output, and how this result if compare with 11 meter of diameter antenna in Splitzberg Groundstation in Norway.

Detection Performance of Upgraded "Polished Panel" Optical Receiver Concept on the Deep-Space Network's 34 Meter Research Antenna

Science.gov (United States)

Vilnrotter, Victor A.

2012-01-01

The development and demonstration of a "polished panel" optical receiver concept on the 34 meter research antenna of the Deep Space Network (DSN) has been the subject of recent papers. This concept would enable simultaneous reception of optical and microwave signals by retaining the original shape of the main reflector for microwave reception, but with the aluminum panels polished to high reflectivity to enable focusing of optical signal energy as well. A test setup has been installed on the DSN's 34 meter research antenna at Deep Space Station 13 (DSS-13) of NASA's Goldstone Communications Complex in California, and preliminary experimental results have been obtained. This paper describes the results of our latest efforts to improve the point-spread function (PSF) generated by a custom polished panel, in an attempt to reduce the dimensions of the PSF, thus enabling more precise tracking and improved detection performance. The design of the new mechanical support structure and its operation are described, and the results quantified in terms of improvements in collected signal energy and optical communications performance, based on data obtained while tracking the planet Jupiter with the 34 meter research antenna at DSS-13.

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

Transmit Antenna Selection for Multi-User Underlay Cognitive Transmission with Zero-Forcing Beamforming

KAUST Repository

Hanif, Muhammad

2017-03-20

We present a transmit antenna subset selection scheme for an underlay cognitive system serving multiple secondary receivers. The secondary system employs zero-forcing beamforming to nullify the interference to multiple primary users and eliminate inter-user interference to the secondary users simultaneously. Simulation results show that the proposed scheme achieves near-optimal performance with low computational complexity. Lastly, an optimal power allocation strategy is also introduced to improve the secondary network throughput.

Investigation of Diagonal Antenna-Chassis Mode in Mobile Terminal LTE MIMO Antennas for Bandwidth Enhancement

DEFF Research Database (Denmark)

Zhang, Shuai; Zhao, Kun; Ying, Zhinong

2015-01-01

mechanism of the mismatch of these three bandwidth ranges is also explained. Furthermore, the diagonal antenna-chassis mode is also studied for MIMO elements in the adjacent and diagonal corner locations. As a practical example, a wideband collocated LTE MIMO antenna is proposed and measured. It covers......A diagonal antenna-chassis mode is investigated in long-term evolution multiple-input-multiple-output (LTE MIMO) antennas. The MIMO bandwidth is defined in this paper as the overlap range of the low-envelope correlation coefficient, high total efficiency, and -6-dB impedance matching bandwidths...... the bands of 740960 and 1700-2700 MHz, where the total efficiencies are better than -3.4 and -1.8 dB, with lower than 0.5 and 0.1, respectively. The measurements agree well with the simulations. Since the proposed method only needs to modify the excitation locations of the MIMO elements on the chassis...

A Modal Description of Multiport Antennas

Directory of Open Access Journals (Sweden)

Jonathan J. Lynch

2011-01-01

Full Text Available This paper presents a modal description of multiport antennas that leads directly to a rigorous network representation and simple quadratic expressions for gain, efficiency, and effective area. The analysis shows that the transmitting and receiving properties of an element antenna array are exactly described by a 2×2 element scattering matrix together with a set of orthonormal mode functions and accounts for effects such as mutual coupling, scattering, reflection, and losses. The approach is quite general, only requiring that the antenna be finite and reciprocal. The scattering network description simplifies accounting of power flow while retaining a close connection to the physical antenna characteristics. The orthonormal mode functions provide a complete basis for radiated and received fields, facilitating beamforming. The theory provides rigorous definitions of input-output signals and links them to the underlying electromagnetics in a straightforward manner.

UWB delay and multiply receiver

Energy Technology Data Exchange (ETDEWEB)

Dallum, Gregory E.; Pratt, Garth C.; Haugen, Peter C.; Romero, Carlos E.

2013-09-10

An ultra-wideband (UWB) delay and multiply receiver is formed of a receive antenna; a variable gain attenuator connected to the receive antenna; a signal splitter connected to the variable gain attenuator; a multiplier having one input connected to an undelayed signal from the signal splitter and another input connected to a delayed signal from the signal splitter, the delay between the splitter signals being equal to the spacing between pulses from a transmitter whose pulses are being received by the receive antenna; a peak detection circuit connected to the output of the multiplier and connected to the variable gain attenuator to control the variable gain attenuator to maintain a constant amplitude output from the multiplier; and a digital output circuit connected to the output of the multiplier.

Joint Transmitter-Receiver Optimization in the Downlink CDMA Systems

Directory of Open Access Journals (Sweden)

Mohammad Saquib

2002-08-01

Full Text Available To maximize the downlink code-division multiple access (CDMA system capacity, we propose to minimize the total transmitted power of the system subject to users′ signal-to-interference ratio (SIR requirements via designing optimum transmitter sequences and utilizing linear optimum receivers (minimum mean square error (MMSE receiver. In our work on joint transmitter-receiver design for the downlink CDMA systems with multiple antennas and multipath channels, we develop several optimization algorithms by considering various system constraints and prove their convergence. We empirically observed that under the optimization algorithm with no constraint on the system, the optimum receiver structure matches the received transmitter sequences. A simulation study is performed to see how the different practical system constraints penalize the system with respect to the optimum algorithm with no constraint on the system.

Boosting the SNR by adding a receive-only endorectal monopole to an external antenna array for high-resolution, T2 -weighted imaging of early-stage cervical cancer with 7-T MRI

NARCIS (Netherlands)

van Kalleveen, I.M.L.; Hoogendam, J.P.; Raaijmakers, A.J.E.; Visser, F.; Arteaga de Castro, C.S.; Verheijen, R.H.M.; Luijten, P.R.; Zweemer, R.P.; Veldhuis, W.B.; Klomp, D.W.J.

The aim of this study was to investigate the signal-to-noise ratio (SNR) gain in early-stage cervical cancer at ultrahigh-field MRI (e.g. 7 T) using a combination of multiple external antennas and a single endorectal antenna. In particular, we used an endorectal monopole antenna to increase the SNR

System and circuit models for microwave antennas

OpenAIRE

Sobhy, Mohammed; Sanz-Izquierdo, Benito; Batchelor, John C.

2007-01-01

This paper describes how circuit and system models are derived for antennas from measurement of the input reflection coefficient. Circuit models are used to optimize the antenna performance and to calculate the radiated power and the transfer function of the antenna. System models are then derived for transmitting and receiving antennas. The most important contribution of this study is to show how microwave structures can be integrated into the simulation of digital communication systems. Thi...

Reply to ''Comment on 'Transmit versus receive gains for microwave dish antennas' [J. Appl. Phys. 54, 3528 (1983)]''

International Nuclear Information System (INIS)

Richter, J.L.

1985-01-01

A. W. Love points out three alleged errors in our paper [J. Appl. Phys. 54, 3528 (1983)]. We agree that he is correct with regard to the second and third issues, but the first and perhaps most important point is correct. This regards the inequality of transmit and receive patterns of microwave antennas. The standard proof of equality of the patterns, cited by A. W. Love, is shown to be incorrect

Inflatable Antennas Support Emergency Communication

Science.gov (United States)

2010-01-01

Glenn Research Center awarded Small Business Innovation Research (SBIR) contracts to ManTech SRS Technologies, of Newport Beach, California, to develop thin film inflatable antennas for space communication. With additional funding, SRS modified the concepts for ground-based inflatable antennas. GATR (Ground Antenna Transmit and Receive) Technologies, of Huntsville, Alabama, licensed the technology and refined it to become the world s first inflatable antenna certified by the Federal Communications Commission. Capable of providing Internet access, voice over Internet protocol, e-mail, video teleconferencing, broadcast television, and other high-bandwidth communications, the systems have provided communication during the wildfires in California, after Hurricane Katrina in Mississippi, and following the 2010 Haiti earthquake.

Improved Reception of In-Body Signals by Means of a Wearable Multi-Antenna System

Directory of Open Access Journals (Sweden)

Thijs Castel

2013-01-01

Full Text Available High data-rate wireless communication for in-body human implants is mainly performed in the 402–405 MHz Medical Implant Communication System band and the 2.45 GHz Industrial, Scientific and Medical band. The latter band offers larger bandwidth, enabling high-resolution live video transmission. Although in-body signal attenuation is larger, at least 29 dB more power may be transmitted in this band and the antenna efficiency for compact antennas at 2.45 GHz is also up to 10 times higher. Moreover, at the receive side, one can exploit the large surface provided by a garment by deploying multiple compact highly efficient wearable antennas, capturing the signals transmitted by the implant directly at the body surface, yielding stronger signals and reducing interference. In this paper, we implement a reliable 3.5 Mbps wearable textile multi-antenna system suitable for integration into a jacket worn by a patient, and evaluate its potential to improve the In-to-Out Body wireless link reliability by means of spatial receive diversity in a standardized measurement setup. We derive the optimal distribution and the minimum number of on-body antennas required to ensure signal levels that are large enough for real-time wireless endoscopy-capsule applications, at varying positions and orientations of the implant in the human body.

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.

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.

Multiband Photonic Phased-Array Antenna

Science.gov (United States)

Tang, Suning

2015-01-01

A multiband phased-array antenna (PAA) can reduce the number of antennas on shipboard platforms while offering significantly improved performance. Crystal Research, Inc., has developed a multiband photonic antenna that is based on a high-speed, optical, true-time-delay beamformer. It is capable of simultaneously steering multiple independent radio frequency (RF) beams in less than 1,000 nanoseconds. This high steering speed is 3 orders of magnitude faster than any existing optical beamformer. Unlike other approaches, this technology uses a single controlling device per operation band, eliminating the need for massive optical switches, laser diodes, and fiber Bragg gratings. More importantly, only one beamformer is needed for all antenna elements.

Transmit selection algorithms for imperfect threshold-based receive MRC in the presence of co-channel interference

KAUST Repository

Radaydeh, Redha Mahmoud Mesleh; Alouini, Mohamed-Slim

2010-01-01

The performance of transmit antenna selection for threshold-based maximal ratio combining (MRC) diversity receivers in the presence of multiple co-channel interfering signals is studied. The impact of imperfect channel estimation of desired user

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°.

Multiport antenna systems for space-time communications

DEFF Research Database (Denmark)

Tsakalaki, Elpiniki; Alrabadi, Osama; Pelosi, Mauro

2013-01-01

The paper presents the concept of multiport antenna systems where multiple active and passive ports are deployed. The passive ports, implemented via tunable reactance-assisted (parasitic) antennas, can alter the far-field and near-field properties of the antenna system expressed by the antenna...... efficiency, electromagnetic coupling and spatial correlation. The system can be optimized in order to enhance the spatial multiplexing performance whereas the performance gains come at no significant additional cost and hardware complexity...

Essential Characteristics of Plasma Antennas Filled with He-Ar Penning Gases

International Nuclear Information System (INIS)

Sun Naifeng; Li Wenzhong; Wang Shiqing; Li Jian; Ci Jiaxiang

2012-01-01

Based on the essential theory of Penning gases, the discharge characteristics of He-Ar Penning gases in insulating tubes were analyzed qualitatively. The relation between the effective length of an antenna column filled with He-Ar Penning gases and the applied radio frequency (RF) power was investigated both theoretically and experimentally. The distribution of the plasma density along the antenna column in different conditions was studied. The receiving characteristics of local frequency modulated (FM) electromagnetic waves by the plasma antenna filled with He-Ar Penning gases were compared with those by an aluminum antenna with the same dimensions. Results show that it is feasible to take plasma antennas filled with He-Ar Penning gases as receiving antennas.

New Configuration of Handset MIMO Antenna for LTE 700 Band Applications

Directory of Open Access Journals (Sweden)

Byeonggwi Mun

2013-01-01

Full Text Available A compact handset multiple-input multiple-output (MIMO antenna for long-term evolution (LTE 700 band (746~787 MHz applications is proposed. The proposed antenna consists of two symmetrical PIFAs. Without the usage of any additional coupling elements between closely mounted antennas, a high isolation (>15 dB and a low enveloped correlation coefficient (ECC<0.35 are achieved by the optimum location and arrangement of MIMO antenna elements.

Wireless Energy Harvesting Using Signals from Multiple Fading Channels

KAUST Repository

Chen, Yunfei; Zhao, Nan; Alouini, Mohamed-Slim

2017-01-01

fading or Gamma-shadowed Rician fading. The received signals are then harvested by using either a single harvester for simultaneous transmissions or multiple harvesters for transmissions at different frequencies, antennas or time slots. Both linear

SKB - PNC. Development of tunnel radar antennas

International Nuclear Information System (INIS)

Falk, L.

1991-07-01

Tunnel antennas for the RAMAC borehole radar system have been developed and tested in the field. The antennas are of the loaded dipole type and the receiver and transmitter electronics have been rebuilt to screen them from the antennas. A series of measurements has demonstrated that the radar pulse is short and well shaped and relatively free from ringing, even compared with the existing borehole antennas. Two antenna sets were tested: one centered at 60 MHz and another above 100 MHz. Both produced excellent radar pictures when tested in tunnels in Stripa mine. The antennas have been designed to be easy to carry, since the signal quality often depends on the way the antenna is held relative to electric conductors in the tunnels. (au) (46 figs., 57 refs.)

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 mesh network operated in a fixed 11 Mbps mode. The throughput improvement in multi-hop communication obtained in the presence of an interferer is tenfold, from 0.2 Mbps to 2 Mbps. Index Terms?antenna, smart antenna, wireless mesh network, WMN... efficiency in the communications, and active research and development of new methods and technologies enabling this at the physical layer, including multiple antenna techniques, such as multiple input multiple output (MIMO) and smart antennas...

Bit Error Rate Due to Misalignment of Earth Station Antenna Pointing to Satellite

Directory of Open Access Journals (Sweden)

Wahyu Pamungkas

2010-04-01

Full Text Available One problem causing reduction of energy in satellite communications system is the misalignment of earth station antenna pointing to satellite. Error in pointing would affect the quality of information signal to energy bit in earth station. In this research, error in pointing angle occurred only at receiver (Rx antenna, while the transmitter (Tx antennas precisely point to satellite. The research was conducted towards two satellites, namely TELKOM-1 and TELKOM-2. At first, measurement was made by directing Tx antenna precisely to satellite, resulting in an antenna pattern shown by spectrum analyzer. The output from spectrum analyzers is drawn with the right scale to describe swift of azimuth and elevation pointing angle towards satellite. Due to drifting from the precise pointing, it influenced the received link budget indicated by pattern antenna. This antenna pattern shows reduction of power level received as a result of pointing misalignment. As a conclusion, the increasing misalignment of pointing to satellite would affect in the reduction of received signal parameters link budget of down-link traffic.

Design of broadband single polarized antenna

Science.gov (United States)

Shin, Phoo Kho; Aziz, Mohamad Zoinol Abidin Abd.; Ahmad, Badrul Hisham; Ramli, Mohamad Hafize Bin; Fauzi, Noor Azamiah Md; Malek, Mohd Fareq Abd

2015-05-01

In practical wireless communication application, bandwidth enhancement becomes one of the major design considerations. At the same time, circular polarized (CP) antenna received much attention for the applications of modern wireless communication system when compared to linear polarized (LP) antenna. This is because CP antenna can reduce the multipath effect. Hence, broadband antenna with operating frequency at 2.4GHz for WLAN application is proposed. The proposed antenna is done by using L-probe amendment with rectangular patch. The rectangular patch and copper ground plane is separated with 10mm air gap. This approach is used to enhance the bandwidth and the gain of the proposed antenna. The bandwidth of the designed antenna is more than 200MHz which meet broadband application. The return loss for the antenna is below -10dB to achieved 90% matching efficiency. The position of L-probe feed is altered in order to obtained different polarizations. The broadband antenna had been designed and simulated by using Computer Simulation Technology (CST) software. In this paper, the comparison for single polarized antenna with the design of non-inverted patch and inverted patch is discussed. The characteristics of the S-parameter, axial ratio, gain, surface current for each designed antenna are analyzed.

Watt-level wireless power transmission to multiple compact receivers

International Nuclear Information System (INIS)

Garraud, A; Munzer, D J; Althar, M; Garraud, N; Arnold, D P

2015-01-01

This paper reports an electrodynamic wireless power transmission (EWPT) system using a low-frequency (300 Hz) magnetic field to transmit watt-scale power levels to multiple compact receivers. As compared to inductively or resonantly coupled coils, EWPT facilitates transmission to multiple non-interacting receivers with little restriction on their orientation. A single 3.0 cm 3 receiver achieves 1.25 W power transmission with 8% efficiency at a distance of 1 cm (350 mW/cm 3 power density) from the transmitter. The same prototype achieves 9 mW at a distance of 9 cm. Moreover, we demonstrate simultaneous recharge of two wearable devices, using two receivers located in arbitrary positions and orientations. (paper)

Array elements for a DBS flat-plate antenna

Science.gov (United States)

Maddocks, M. C. D.

1988-07-01

The introduction of a direct broadcast by satellite (DBS) television service requires suitable receiving antennas to be available. An alternative to the parabolic dish antenna is a flat-plate antenna. The overall design of a circularly-polarized flat-plate antenna which can be mounted flat on the wall of a building has been considered in a companion Report. In this Report various types of elements are investigated and their advantages and disadvantages discussed. The most suitable element for use in a flat-plate array is identified as a linearly-polarized folded-dipole element; its performance is reported here. Linearly-polarized elements are found to perform better than circularly-polarized elements and could be used with a polarization converter to receive the circularly-polarized radiation that would be transmitted by DBS.

Multi-spectrum and transmit-antenna switched diversity schemes for spectrum sharing systems: A performance analysis

KAUST Repository

Sayed, Mostafa

2012-12-01

In spectrum sharing systems, a secondary user (SU) is allowed to share the spectrum with a primary licensed user under the condition that the interference at the the primary user receiver (PU-Rx) is below a predetermined threshold. Joint primary spectrum and transmit antenna selection diversity schemes can be utilized as an efficient way to meet the quality of service (QoS) demands of the SUs while satisfying the interference constraint. In this paper, we consider a secondary link comprised of a secondary transmitter (SU-Tx) equipped with multiple antennas and a single-antenna secondary receiver (SU-Rx) sharing the same spectrum with a number of primary users (PUs) operating at distinct spectra. We present a performance analysis for two primary spectrum and transmit antenna switched selection schemes with different amount of feedback requirements. In particular, assuming Rayleigh fading and BPSK transmission, we derive approximate BER expressions for the presented schemes. For the sake of comparison, we also derive a closed-form BER expression for the optimal selection scheme that selects the best pair in terms of the SU-Rx signal-to-noise ratio (SNR) which has the disadvantage of high feedback requirements. Finally, our results are verified with numerical simulations. © 2012 IEEE.

Continuous zoom antenna for mobile visible light communication.

Science.gov (United States)

Zhang, Xuebin; Tang, Yi; Cui, Lu; Bai, Tingzhu

2015-11-10

In this paper, we design a continuous zoom antenna for mobile visible light communication (VLC). In the design, a right-angle reflecting prism was adopted to fold the space optical path, thus decreasing the antenna thickness. The surface of each lens in the antenna is spherical, and the system cost is relatively low. Simulation results indicated that the designed system achieved the following performance: zoom ratio of 2.44, field of view (FOV) range of 18°-48°, system gain of 16.8, and system size of 18 mm×6  mm. Finally, we established an indoor VLC system model in a room the size of 5  m ×5  m ×3  m and compared the detection results of the zoom antenna and fixed-focus antenna obtained in a multisource communication environment, a mobile VLC environment, and a multiple-input multiple-output communication environment. The simulation results indicated that the continuous zoom antenna could realize large FOV and high gain. Moreover, the system showed improved stability, mobility, and environmental applicability.

Compact super-wideband optical antenna

Science.gov (United States)

Wang, Wen C.; Forber, Richard; Bui, Kenneth

2009-05-01

We present progress on advanced optical antennas, which are compact, small size-weight-power units capable to receive super wideband radiated RF signals from 30 MHz to over 3 GHz. Based on electro-optical modulation of fiber-coupled guided wave light, these dielectric E-field sensors exhibit dipole-like azimuthal omni directionality, and combine small size (channels, and high EO sensing materials. The antenna system photonic link consists of a 1550 nm PM fiber-pigtailed laser, a specialized optical modulator antenna in channel waveguide format, a wideband photoreceiver, and optical phase stabilizing components. The optical modulator antenna design employs a dielectric (no electrode) Mach-Zehnder interferometer (MZI) arranged so that sensing RF bandwidth is not limited by optical transit time effects, and MZI phase drift is bias stabilized. For a prototype optical antenna system that is < 100 in3, < 10 W, < 5 lbs, we present test data on sensitivity (< 20 mV/m-Hz1/2), RF bandwidth, and antenna directionality, and show good agreement with theoretical predictions.

Multiband Patch Antenna for Femtocell Application

Directory of Open Access Journals (Sweden)

M. R. Zaman

2014-01-01

Full Text Available A microstrip patch antenna for multiple LTE (long term evaluation frequency bands for femtocell application is proposed in this paper. Distributed antenna solution (DAS has been introduced in cellular network to achieve homogenous indoor coverage. Femtocell is the latest extension to these solutions. It is a smart solution to both coverage and capacity scales. Femtocell operation in LTE band is occupied by higher frequency bands. For multiband femtocell application, miniature antenna design is quite essential. The antenna proposed here is composed of basic monopole structure with two parasitic elements at both sides of the active element. A rectangular slot is introduced at the ground plane of the proposed antenna. The antenna is designed using ElnoS HK light CCL substrate material of relative permittivity of 9.4, dielectric loss-tangent of 0.003 and thickness of 3 mm. The S11 response of the antenna is shown to have a bandwidth of 1.01 GHz starting from 1.79 GHz to 2.8 GHz. The characteristics of the antenna are analysed using Ansoft HFSS software.

Low-Complexity Transmit Antenna Selection and Beamforming for Large-Scale MIMO Communications

Directory of Open Access Journals (Sweden)

Kun Qian

2014-01-01

Full Text Available Transmit antenna selection plays an important role in large-scale multiple-input multiple-output (MIMO communications, but optimal large-scale MIMO antenna selection is a technical challenge. Exhaustive search is often employed in antenna selection, but it cannot be efficiently implemented in large-scale MIMO communication systems due to its prohibitive high computation complexity. This paper proposes a low-complexity interactive multiple-parameter optimization method for joint transmit antenna selection and beamforming in large-scale MIMO communication systems. The objective is to jointly maximize the channel outrage capacity and signal-to-noise (SNR performance and minimize the mean square error in transmit antenna selection and minimum variance distortionless response (MVDR beamforming without exhaustive search. The effectiveness of all the proposed methods is verified by extensive simulation results. It is shown that the required antenna selection processing time of the proposed method does not increase along with the increase of selected antennas, but the computation complexity of conventional exhaustive search method will significantly increase when large-scale antennas are employed in the system. This is particularly useful in antenna selection for large-scale MIMO communication systems.

Antenna Selection for Full-Duplex MIMO Two-Way Communication Systems

KAUST Repository

Wilson-Nunn, Daniel; Chaaban, Anas; Sezgin, Aydin; Alouini, Mohamed-Slim

2017-01-01

Antenna selection for full-duplex communication between two nodes, each equipped with a predefined number of antennae and transmit/receive chains, is studied. Selection algorithms are proposed based on magnitude, orthogonality, and determinant criteria. The algorithms are compared to optimal selection obtained by exhaustive search as well as random selection, and are shown to yield performance fairly close to optimal at a much lower complexity. Performance comparison for a Rayleigh fading symmetric channel reveals that selecting a single transmit antenna is best at low signal-to-noise ratio (SNR), while selecting an equal number of transmit and receive antennae is best at high SNR.

Antenna Selection for Full-Duplex MIMO Two-Way Communication Systems

KAUST Repository

Wilson-Nunn, Daniel

2017-03-11

Antenna selection for full-duplex communication between two nodes, each equipped with a predefined number of antennae and transmit/receive chains, is studied. Selection algorithms are proposed based on magnitude, orthogonality, and determinant criteria. The algorithms are compared to optimal selection obtained by exhaustive search as well as random selection, and are shown to yield performance fairly close to optimal at a much lower complexity. Performance comparison for a Rayleigh fading symmetric channel reveals that selecting a single transmit antenna is best at low signal-to-noise ratio (SNR), while selecting an equal number of transmit and receive antennae is best at high SNR.

The Millimeter Wave Observatory antenna now at INAOE-Mexico

Science.gov (United States)

Luna, A.

2017-07-01

The antenna of 5 meters in diameter of the legendary "Millimeter Wave Observatory" is now installed in the INAOE-Mexico. This historic antenna was reinstalled and was equipped with a control system and basic primary focus receivers that enabled it in teaching activities. We work on the characterization of its surface and on the development of receivers and spectrometers to allow it to do research Solar and astronomical masers. The historical contributions of this antenna to science and technology in radio astronomy, serve as the guiding force and the inspiration of the students and technicians of our postgrade in Astrophysics. It is enough to remember that it was with this antenna, that the first molecular outflow was discovered, several lines of molecular emission were discovered and it was the first antenna whose surface was characterized by holography; among many other technological and scientific contributions.

Antennas for mobile satellite communications

Science.gov (United States)

Huang, John

1991-12-01

A NASA sponsored program, called the Mobile Satellite (MSAT) system, has prompted the development of several innovative antennas at L-band frequencies. In the space segment of the MSAT system, an efficient, light weight, circularly polarized microstrip array that uses linearly polarized elements was developed as a multiple beam reflector feed system. In the ground segment, a low-cost, low-profile, and very efficient microstrip Yagi array was developed as a medium-gain mechanically steered vehicle antenna. Circularly shaped microstrip patches excited at higher-order modes were also developed as low-gain vehicle antennas. A more recent effort called for the development of a 20/30 GHz mobile terminal antenna for future-generation mobile satellite communications. To combat the high insertion loss encountered at 20/30 GHz, series-fed Monolithic Microwave Integrated Circuit (MMIC) microstrip array antennas are currently being developed. These MMIC arrays may lead to the development of several small but high-gain Ka-band antennas for the Personal Access Satellite Service planned for the 2000s.

Performance Verification on UWB Antennas for Breast Cancer Detection

Directory of Open Access Journals (Sweden)

Vijayasarveswari V.

2017-01-01

Full Text Available Breast cancer is a common disease among women and death figure is continuing to increase. Early breast cancer detection is very important. Ultra wide-band (UWB is the promising candidate for short communication applications. This paper presents the performance of different types of UWB antennas for breast cancer detection. Two types of antennas are used i.e: UWB pyramidal antenna and UWB horn antenna. These antennas are used to transmit and receive the UWB signal. The collected signals are fed into developed neural network module to measure the performance efficiency of each antenna. The average detection efficiency is 88.46% and 87.55% for UWB pyramidal antenna and UWB horn antenna respectively. These antennas can be used to detect breast cancer in the early stage and save precious lives.

A Combined Antenna Arrays and Reverse-Link Synchronous DS-CDMA System over Frequency-Selective Fading Channels with Power Control Error

Directory of Open Access Journals (Sweden)

Yong-Seok Kim

2004-08-01

Full Text Available An improved antenna array (AA has been introduced, in which reverse-link synchronous transmission technique (RLSTT is incorporated to effectively make better an estimation of covariance matrices at a beamformer-RAKE receiver. While RLSTT is effective in the first finger at the RAKE receiver in order to reject multiple-access interference (MAI, the beamformer estimates the desired user's complex weights, enhancing its signal and reducing cochannel interference (CCI from the other directions. In this work, it is attempted to provide a comprehensive analysis of user capacity which reflects several important factors such as the shape of multipath intensity profile (MIP, the number of antennas, and power control error (PCE. Theoretical analysis, confirmed by the simulations, demonstrates that the orthogonality provided by employing RLSTT along with AA may make the DS-CDMA system insensitive to the PCE even with fewer numbers of antennas.

Progress in Body-Worn Antennas for On-Body Propagation (invited)

DEFF Research Database (Denmark)

Jakobsen, Kaj Bjarne

2016-01-01

On-body propagation and on-body antennas for body-centric wireless communications are presented. The onbody communications rely on creeping waves launched and received by the antennas, respectively. Path gain and bandwidth at 2.4 GHz for different types of body-worn antennas for head-centric comm...

Self-matched high-Q reconfigurable antenna concept for mobile terminals

DEFF Research Database (Denmark)

Bahramzy, Pevand; Jagielski, Ole; Svendsen, Simon

2014-01-01

This study presents reconfigurable antenna design for a front end (FE) that has separate transmit (Tx) and receive (Rx) path. In such an FE, the Tx and Rx antennas can be content with covering only the transmit and receive channels in a frequency band. Therefore they can be quite narrow-band. Nar...

An Efficient Rank Adaptation Algorithm for Cellular MIMO Systems with IRC Receivers

DEFF Research Database (Denmark)

Mahmood, Nurul Huda; Berardinelli, Gilberto; Tavares, Fernando Menezes Leitão

2014-01-01

Multiple transmit and receive antennas introduce additional degrees of freedom, which can be used to increase the number of spatial channels between a transmitter-receiver pair. Alternately, the additional degrees of freedom can be used to improve the interference resilience property with the help...... algorithm based on an estimate of the mean signal-to-interference-plus-noise ratio (SINR) at an IRC receiver; wherein, we use results from random matrix theory to derive the expression for the mean post-IRC SINR in the presence of interferers with unequal powers. The performance of the proposed algorithm...

Improvement of antenna decoupling in radar systems

Science.gov (United States)

Anchidin, Liliana; Topor, Raluca; Tamas, Razvan D.; Dumitrascu, Ana; Danisor, Alin; Berescu, Serban

2015-02-01

In this paper we present a type of antipodal Vivaldi antenna design, which can be used for pulse radiation in UWB communication. The Vivaldi antenna is a special tapered slot antenna with planar structure which is easily to be integrated with transmitting elements and receiving elements to form a compact structure. When the permittivity is very large, the wavelength of slot mode is so short that the electromagnetic fields concentrate in the slot to form an effective and balanced transmission line. Due to its simple structure and small size the Vivaldi antennas are one of the most popular designs used in UWB applications. However, for a two-antenna radar system, there is a high mutual coupling between two such antennas due to open configuration. In this paper, we propose a new method for reducing this effect. The method was validated by simulating a system of two Vivaldi antennas in front of a standard target.

Quasi-optical antenna-mixer-array design for terahertz frequencies

Science.gov (United States)

Guo, Yong; Potter, Kent A.; Rutledge, David B.

1992-01-01

A new quasi-optical antenna-mixer-array design for terahertz frequencies is presented. In the design, antenna and mixer are combined into an entity, based on the technology in which millimeter-wave horn antenna arrays have been fabricated in silicon wafers. It consists of a set of forward- and backward-looking horns made with a set of silicon wafers. The front side is used to receive incoming signal, and the back side is used to feed local oscillator signal. Intermediate frequency is led out from the side of the array. Signal received by the horn array is picked up by antenna probes suspended on thin silicon-oxynitride membranes inside the horns. Mixer diodes will be located on the membranes inside the horns. Modeling of such an antenna-mixer-array design is done on a scaled model at microwave frequencies. The impedance matching, RF and LO isolation, and patterns of the array have been tested and analyzed.

The Use of Conductive Ink in Antenna Education and Design

Science.gov (United States)

Addison, David W.

Conductive ink from a printer allows for the fabrication of conductive material with tight tolerances without the cost and time of chemical etching. This paper explores the use of AGIC printable conductive ink on a paper substrate as design tool for antennas as well as classroom use in antenna education. The antenna designs satisfy the requirements of a compact Global Navigation Satellite System (GNSS) antenna while showing a competitive performance within the current market. One best design is shown along with three other structures. These antennas consist of a bowtie cross-dipole over a reflective disc with conductive-ink grounded structures. In addition to the GNSS antennas, a linear elliptical dipole over a reflective disc with conductive grounded structures is presented. This elliptical antenna design attempts to find the maximum impedance bandwidth beyond the GNSS band. The inexpensive nature of conductive ink allows for its use in a classroom to demonstrate antenna behavior as part of antenna education. An inexpensive approach to the patch antenna using conductive ink is described and paired with a system made of off-the-shelf parts. The system is capable of measuring the power of the received signal. The received signal measurement is not as accurate as using a anechoic chamber but pattern details are visible. This is used to demonstrate aspects of the Friis transmission equation such as distance, polarization, radiation pattern shape, and loss.

Archimedean Spiral Antenna Calibration Procedures to Increase the Downrange Resolution of a SFCW Radar

Directory of Open Access Journals (Sweden)

Ioan Nicolaescu

2008-01-01

Full Text Available This paper deals with the calibration procedures of an Archimedean spiral antenna used for a stepped frequency continuous wave radar (SFCW, which works from 400 MHz to 4845 MHz. Two procedures are investigated, one based on an error-term flow graph for the frequency signal and the second based on a reference metallic plate located at a certain distance from the ground in order to identify the phase dispersion given by the antenna. In the second case, the received signal is passed in time domain by applying an ifft, the multiple reflections are removed and the phase variation due to the time propagation is subtracted. After phase correction, the time domain response as well as the side lobes level is decreased. The antenna system made up of two Archimedean spirals is employed by SFCW radar that operates with a frequency step of 35 MHz.

Performance of Antenna Selection in MIMO System Using Channel Reciprocity with Measured Data

Directory of Open Access Journals (Sweden)

Peerapong Uthansakul

2011-01-01

Full Text Available The channel capacity of MIMO system increases as a function of antenna pairs between transmitter and receiver but it suffers from multiple expensive RF chains. To reduce cost of RF chains, antenna selection (AS method can offer a good tradeoff between expense and performance. For a transmitting AS system, channel state information (CSI feedback is required to choose the best subset of available antennas. However, the delay and error in feedback channel are the most dominant factors to degrade performances. In this paper, the concept of AS method using reciprocal CSI instead of feedback channel is proposed. The capacity performance of proposed system is investigated by own developing Testbed. The obtained results indicate that the reciprocity technique offers a capacity close to a system with perfect CSI and gains a higher capacity than a system without AS method. This benefit is from 0.9 to 2.2 bps/Hz at SNR 10 dB.

Waveguide Phased Array Antenna Analysis and Synthesis

NARCIS (Netherlands)

Visser, H.J.; Keizer, W.P.M.N.

1996-01-01

Results of two software packages for analysis and synthesis of waveguide phased array antennas are shown. The antennas consist of arrays of open-ended waveguides where irises can be placed in the waveguide apertures and multiple dielectric sheets in front of the apertures in order to accomplish a

MIMO channel capacity versus mutual coupling in multi antenna element system

DEFF Research Database (Denmark)

Thaysen, Jesper; Jakobsen, Kaj Bjarne

2004-01-01

In this paper the influence of mutual coupling on the capacity of a multiple-input multiple-output (MIMO) antenna system is demonstrated. No direct relation between the envelope correlation and the actual location and orientation of the antennas is found. Even though being essential for high MIMO...... capacity, configurations with the lowest envelope correlations are not necessarily the most suitable for a MIMO system. A certain bandwidth is required as well. Three planar inverted F-antennas (PIFA) located on the same 40 mm x 100 mm ground plane. The antennas that haves a resonant frequency of 1.8 GHz...

Detection of a buried object with pulse-compensated wire antennas

NARCIS (Netherlands)

Vossen, S.H.J.A.; Tijhuis, A.G.; Lepelaars, E.S.A.M.; Zwamborn, A.P.M.

2003-01-01

For the detection of a buried object we consider two straight thin-wire antennas above an interface between two homogeneous dielectric half spaces. One antenna is a transmitting wire and the other is a receiving wire. Our aim is to use this simple antenna set up for the detection of buried objects

Diversity receiver

NARCIS (Netherlands)

2005-01-01

The invention is directed to the reception of high rate radio signals (for example DVB-T signals) while the receiver is moving at a high speed (for example in or with a car). Two or more antennas (12, 16) are closely spaced and arranged behind each other in the direction of motion (v) for receiving

Measuring Balance Across Multiple Radar Receiver Channels.

Energy Technology Data Exchange (ETDEWEB)

Doerry, Armin W.; Bickel, Douglas L.

2018-03-01

When radar receivers employ multiple channels, the general intent is for the receive channels to be as alike as possible, if not as ideal as possible. This is usually done via prudent hardware design, supplemented by system calibration. Towards this end, we require a quality metric for ascertaining the goodness of a radar channel, and the degree of match to sibling channels. We propose a relevant and useable metric to do just that. Acknowledgements This report was the result of an unfunded research and development activity.

Highly Compact MIMO Antenna System for LTE/ISM Applications

Directory of Open Access Journals (Sweden)

Lingsheng Yang

2015-01-01

Full Text Available Planar monopole antenna is proposed as the antenna element to form a compact dual-element multiple-input-multiple-output (MIMO antenna system for LTE2300 (used in Asia and Africa and ISM band operation. The system can cover a 310 MHz (2.20–2.51 GHz operating bandwidth, with the total size of 15.5 mm × 18 mm × 1.6 mm. Measured isolation higher than 16 dB is obtained without any specially designed decoupling structures, while the edge-to-edge element spacing is only 7.8 mm (0.08λ at 2.20 GHz. Radiation characteristics, correlation coefficient, and the performance of the whole system with a metal sheet and a plastic housing show this system is competitive for practical MIMO applications. The antenna element is further used to build an eight-element MIMO antenna system; also good results are achieved.

Mode Theory of Multi-Armed Spiral Antennas and Its Application to Electronic Warfare Antennas

Science.gov (United States)

Radway, Matthew J.

Since their invention about 55 years ago, spiral antennas have earned a reputation for providing stable impedance and far-field patterns over multi-decade frequency ranges. For the first few decades these antennas were researched for electronic warfare receiving applications, primarily in the 2-18 GHz range. This research was often done under conditions of secrecy, and often by private contractors who did not readily share their research, and now have been defunct for decades. Even so, the body of literature on the two-armed variant of these antennas is rich, often leading non-specialists to the misconception that these antennas are completely understood. Furthermore, early work was highly experimental in nature, and was conducted before modern data collection and postprocessing capabilities were widespread, which limited the range of the studies. Recent research efforts have focused on extending the application of spirals into new areas, as well as applying exotic materials to `improve' their performance and reduce their size. While interesting results have been obtained, in most instances these were incomplete, often compromising the frequency independent nature of these antennas. This thesis expands the role of the multi-armed spiral outside of its traditional niche of receive-only monopulse direction finding. As a first step, careful study of the spiral-antenna mode theory is undertaken with particular attention paid to the concepts of mode filtering and modal decomposition. A technique for reducing the modal impedance of high arm-count spirals is introduced. The insights gained through this theoretical study are first used to improve the far-field performance of the coiled-arm spiral antenna. Specifically, expanding the number of arms on a coiled arm spiral from two to four while providing proper excitation enables dramatically improved broadside axial ratio and azimuthal pattern uniformity. The multiarming technique is then applied to the design of an antenna

Secret-key agreement over spatially correlated multiple-antenna channels in the low-SNR regime

KAUST Repository

Zorgui, Marwen; Rezki, Zouheir; Alomair, Basel; Jorswieck, Eduard A.; Alouini, Mohamed-Slim

2015-01-01

We consider secret-key agreement with public discussion over Rayleigh fast-fading channels with transmit, receive and eavesdropper correlation. The legitimate receiver along with the eavesdropper are assumed to have perfect channel knowledge while the transmitter has only knowledge of the correlation matrices. We analyze the secret-key capacity in the low signal-to-noise ratio (SNR) regime. We derive closed-form expressions for the first and the second derivatives of the secret-key capacity with respect to SNR at SNR= 0, for arbitrary correlation matrices and number of transmit, receive and eavesdropper antennas. Moreover, we identify optimal transmission strategies achieving these derivatives. For instance, we prove that achieving the first and the second derivatives requires a uniform power distribution between the eigenvectors spanning the maximal-eigenvalue eigenspace of the transmit correlation matrix. We also compare the optimal transmission scheme to a simple uniform power allocation. Finally, we express the minimum energy required for sharing a secret-key bit as well as the wideband slope in terms of the system parameters.

Secret-key agreement over spatially correlated multiple-antenna channels in the low-SNR regime

KAUST Repository

Zorgui, Marwen

2015-09-28

We consider secret-key agreement with public discussion over Rayleigh fast-fading channels with transmit, receive and eavesdropper correlation. The legitimate receiver along with the eavesdropper are assumed to have perfect channel knowledge while the transmitter has only knowledge of the correlation matrices. We analyze the secret-key capacity in the low signal-to-noise ratio (SNR) regime. We derive closed-form expressions for the first and the second derivatives of the secret-key capacity with respect to SNR at SNR= 0, for arbitrary correlation matrices and number of transmit, receive and eavesdropper antennas. Moreover, we identify optimal transmission strategies achieving these derivatives. For instance, we prove that achieving the first and the second derivatives requires a uniform power distribution between the eigenvectors spanning the maximal-eigenvalue eigenspace of the transmit correlation matrix. We also compare the optimal transmission scheme to a simple uniform power allocation. Finally, we express the minimum energy required for sharing a secret-key bit as well as the wideband slope in terms of the system parameters.

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

KAUST Repository

Benkhelifa, Fatma; Alouini, Mohamed-Slim

2016-01-01

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.

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.

OFDM versus Single Carrier: A Realistic Multi-Antenna Comparison

Directory of Open Access Journals (Sweden)

Moonen Marc

2004-01-01

Full Text Available There is an ongoing discussion in the broadband wireless world about the respective benefits of orthogonal frequency division multiplexing (OFDM and single carrier with frequency domain equalization (SC-FD. SC-FD allows for more relaxed front-end requirements, of which the power amplifier efficiency is very important for battery-driven terminals. OFDM, on the other hand, can yield improved BER performance at low complexity. Both schemes have extensions to multiple antennas to enhance the spectral efficiency and/or the link reliability. Moreover, both schemes have nonlinear versions using decision feedback equalization (DFE to further improve performance of the linear equalizers. In this paper, we compare these high-performance OFDM and SC-FD schemes using multiple antennas and DFE, while also accounting for the power amplifier efficiency. To make a realistic comparison, we also consider most important digital imperfections, such as channel and noise estimation, transmit and receive filtering, clipping and quantization, as well as link layer impact. Our analysis shows that for frequency-selective channels the relative performance impact of the power amplifier is negligible compared to the frequency diversity impact. The higher frequency diversity exploitation of SC-FD allows it to outperform OFDM in most cases. Therefore, SC-FD is a suitable candidate for broadband wireless communication.

Highly miniaturised semi-loop meandered dual-band MIMO antenna system

KAUST Repository

Jehangir, Syed S.

2017-12-05

A novel dual-band two-element directional multiple-input-multiple-output (MIMO) antenna system is presented with 68% miniaturisation, which is achieved using a semi-loop meandered driven element and a small ground plane. The centre frequency of operation is 2 GHz. The antenna system covers two bands: the telemetry L-band 1.27-1.43 GHz and the global system for mobile communications/long-term evolution band 1.8-2.133 GHz. The simulation and measurement results are in good agreement. The proposed antenna system mimics the quasi-Yagi antenna configuration with a measured front-to-back ratio of around 15 dB at 1.35 GHz and 17 dB at 2 GHz, which is achieved without using a large ground plane, extra metallic structures, multiple reflector elements, or any complex technique. A gain of more than 5 dBi is measured for the single element with a total radiation efficiency of around 85% in both bands. The measured isolation of the proposed MIMO antenna is more than 15 dB with < 0.0785 measured envelope correlation coefficient values in both bands.

Highly miniaturised semi-loop meandered dual-band MIMO antenna system

KAUST Repository

Jehangir, Syed S.; Sharawi, Mohammad S.; Shamim, Atif

2017-01-01

A novel dual-band two-element directional multiple-input-multiple-output (MIMO) antenna system is presented with 68% miniaturisation, which is achieved using a semi-loop meandered driven element and a small ground plane. The centre frequency of operation is 2 GHz. The antenna system covers two bands: the telemetry L-band 1.27-1.43 GHz and the global system for mobile communications/long-term evolution band 1.8-2.133 GHz. The simulation and measurement results are in good agreement. The proposed antenna system mimics the quasi-Yagi antenna configuration with a measured front-to-back ratio of around 15 dB at 1.35 GHz and 17 dB at 2 GHz, which is achieved without using a large ground plane, extra metallic structures, multiple reflector elements, or any complex technique. A gain of more than 5 dBi is measured for the single element with a total radiation efficiency of around 85% in both bands. The measured isolation of the proposed MIMO antenna is more than 15 dB with < 0.0785 measured envelope correlation coefficient values in both bands.

Antennas Designed for Advanced Communications for Air Traffic Management (AC/ATM) Project

Science.gov (United States)

Zakrajsek, Robert J.

2000-01-01

The goal of the Advanced Communications for Air Traffic Management (AC/ATM) Project at the NASA Glenn Research Center at Lewis Field is to enable a communications infrastructure that provides the capacity, efficiency, and flexibility necessary to realize a mature free-flight environment. The technical thrust of the AC/ATM Project is targeted at the design, development, integration, test, and demonstration of enabling technologies for global broadband aeronautical communications. Since Ku-band facilities and equipment are readily available, one of the near-term demonstrations involves a link through a Kuband communications satellite. Two conformally mounted antennas will support the initial AC/ATM communications links. Both of these are steered electronically through monolithic microwave integrated circuit (MMIC) amplifiers and phase shifters. This link will be asymmetrical with the downlink to the aircraft (mobile vehicle) at a throughput rate of greater than 1.5 megabits per second (Mbps), whereas the throughput rate of the uplink from the aircraft will be greater than 100 kilobits per second (kbps). The data on the downlink can be narrow-band, wide-band, or a combination of both, depending on the requirements of the experiment. The AC/ATM project is purchasing a phased-array Ku-band transmitting antenna for the uplink from the test vehicle. Many Ku-band receiving antennas have been built, and one will be borrowed for a short time to perform the initial experiments at the NASA Glenn Research Center at Lewis Field. The Ku-band transmitting antenna is a 254-element MMIC phased-array antenna being built by Boeing Phantom Works. Each element can radiate 100 mW. The antenna is approximately 43-cm high by 24-cm wide by 3.3-cm thick. It can be steered beyond 60 from broadside. The beamwidth varies from 6 at broadside to 12 degrees at 60 degrees, which is typical of phased-array antennas. When the antenna is steered to 60 degrees, the beamwidth will illuminate

Throughput Measurement of a Dual-Band MIMO Rectangular Dielectric Resonator Antenna for LTE Applications.

Science.gov (United States)

Nasir, Jamal; Jamaluddin, Mohd Haizal; Ahmad Khan, Aftab; Kamarudin, Muhammad Ramlee; Yen, Bruce Leow Chee; Owais, Owais

2017-01-13

An L-shaped dual-band multiple-input multiple-output (MIMO) rectangular dielectric resonator antenna (RDRA) for long term evolution (LTE) applications is proposed. The presented antenna can transmit and receive information independently using fundamental TE 111 and higher order TE 121 modes of the DRA. TE 111 degenerate mode covers LTE band 2 (1.85-1.99 GHz), 3 (1.71-1.88 GHz), and 9 (1.7499-1.7849 GHz) at f r = 1.8 GHz whereas TE 121 covers LTE band 7 (2.5-2.69 GHz) at f r = 2.6 GHz, respectively. An efficient design method has been used to reduce mutual coupling between ports by changing the effective permittivity values of DRA by introducing a cylindrical air-gap at an optimal position in the dielectric resonator. This air-gap along with matching strips at the corners of the dielectric resonator keeps the isolation at a value more than 17 dB at both the bands. The diversity performance has also been evaluated by calculating the envelope correlation coefficient, diversity gain, and mean effective gain of the proposed design. MIMO performance has been evaluated by measuring the throughput of the proposed MIMO antenna. Experimental results successfully validate the presented design methodology in this work.

Mutual Coupling Effects on Pattern Diversity Antennas for MIMO Femtocells

Directory of Open Access Journals (Sweden)

Yue Gao

2010-01-01

Full Text Available Diversity antennas play an important role in wireless communications. However, mutual coupling between multiple ports of a diversity antenna has significant effects on wireless radio links and channel capacity. In this paper, dual-port pattern diversity antennas for femtocell applications are proposed to cover GSM1800, UMTS, and WLAN frequency bands. The channel capacities of the proposed antennas and two ideal dipoles with different mutual coupling levels are investigated in an indoor environment. The relation between mutual coupling and channel capacity is observed through investigations of these antennas.

Antenna development for astroparticle and radioastronomy experiments

Energy Technology Data Exchange (ETDEWEB)

Charrier, Didier, E-mail: charrier@emn.fr [Subatech, Ecole des Mines de Nantes - CNRS/IN2P3 - Universite de Nantes (France)

2012-01-11

An active dipole antenna is in operation since five years at the Nancay radio Observatory (France) in the CODALEMA experiment. A new version of this active antenna has been developed, whose shape gave its name of 'Butterfly' antenna. Compared to the previous version, this new antenna has been designed to be more efficient at low frequencies, which could permit the detection of atmospheric showers at large distances. Despite a size of only 2 m Multiplication-Sign 1 m in each polarization, its sensitivity is excellent in the 30-80 MHz bandwidth. Three antennas in dual polarization were installed on the CODALEMA experiment, and four other have been recently installed on the Auger area in the scope of the AERA project. The main characteristics of the Butterfly antenna are detailed with an emphasis on its key features which make it a good candidate for the low frequency radioastronomy and the radio detection of transients induced by high energy cosmic rays.

A High Isolation MIMO Antenna without Decoupling Structure for LTE 700 MHz

Directory of Open Access Journals (Sweden)

Yanjie Wu

2015-01-01

Full Text Available This paper presents a long-term evolution (LTE 700 MHz band multiple-input-multiple-output (MIMO antenna, and high isolation between the two symmetrical antenna elements is obtained without introducing extra decoupling structure. Each antenna element is a combination antenna of PIFA and a meander monopole antenna. The end of the PIFA and the meander monopole antenna are, respectively, overlapped with the 50 Ω microstrip feed line, the two overlapping areas produce additional capacitance which can be considered decoupling structures to enhance the isolation for the MIMO antenna, as well as the impedance matching of the antenna elements. The MIMO antenna is etched on FR4 PCB board with dimensions of 71 × 40 × 1.6 mm3; the edge-to-edge separation of the two antenna elements is only nearly 0.037 λ at 700 MHz. Both simulation and measurement results are used to confirm the MIMO antenna performance; the operating bandwidth is 698–750 MHz with S11≤−6 dB and S21≤−23 dB.

Broadband standard dipole antenna for antenna calibration

Science.gov (United States)

Koike, Kunimasa; Sugiura, Akira; Morikawa, Takao

1995-06-01

Antenna calibration of EMI antennas is mostly performed by the standard antenna method at an open-field test site using a specially designed dipole antenna as a reference. In order to develop broadband standard antennas, the antenna factors of shortened dipples are theoretically investigated. First, the effects of the dipole length are analyzed using the induced emf method. Then, baluns and loads are examined to determine their influence on the antenna factors. It is found that transformer-type baluns are very effective for improving the height dependence of the antenna factors. Resistive loads are also useful for flattening the frequency dependence. Based on these studies, a specification is developed for a broadband standard antenna operating in the 30 to 150 MHz frequency range.

Eight-Element Antenna Array for LTE 3.4-3.8 GHz Mobile Handset Applications

Science.gov (United States)

Yang, Lingsheng; Ji, Ming; Cheng, Biyu; Ni, Bo

2017-05-01

In this letter, an eight-element Multiple-input multiple-output (MIMO) antenna system for LTE mobile handset applications is proposed. The antenna array consists of eight 3D inverted F-shaped antennas (3D-IFA), and the measured -10 dB impedance bandwidth is 3.2-3.9 GHz which can cover the LTE bands 42 and 43 (3.4-3.8 GHz). By controlling the rotation of the antenna elements, no less than 10 dB isolation between antenna elements can be obtained. After using the specially designed meandered slots on the ground as decoupling structures, the measured isolation can be further improved to higher than 13 dB between the antenna elements at the whole operating band.

More About Lens Antenna For Mobile/Satellite Communication

Science.gov (United States)

Rahmat-Samii, Y.; Bodnar, D. G.; Rainer, B. K.

1990-01-01

Report presents additional details of design of proposed phased-array antenna described in "Lens Antenna for Mobile/Satellite Communication" (NPO-16948). Intended to be compact and to lie flat on top of vehicle on ground. Transmits and receives circularly polarized radiation in frequency ranges of 821 to 825 MHz and 860 to 870 MHz. Transmitting and receiving beams electronically steerable to any of 48 evenly spaced directions to provide complete azimuth coverage, and would be fixed, but wide, in elevation, to provide coverage at elevation angles from 20 degrees to 60 degrees.

History of Antenna Technology for Mobile Communications in Korea

Science.gov (United States)

Min, Kyeong-Sik; Park, Chul-Keun; Kang, Suk-Youb

In this paper, we discuss the development of wireless and mobile communications in Korea, current technological trends, and the future outlook on technological developments. Since the introduction of the telegraph and the telephone in September 1885, Korea's wired and wireless communications industry has consistently developed for over 100 years. Since 1984, upon the provision of the mobile telecommunications service, the industry has seen drastic qualitative and quantitative growth in terms of both technical and economic aspects, which played a crucial role in the rapid growth of the digital industry in Korea. After the era of the analog cellular service based on the Advanced Mobile Phone System (AMPS), a precursor to the modern mobile service, Korea became the world's first country to commercialize Code Division Multiple Access (CDMA) in 1996 and succeeded in commercializing CDMA 2000 lx (IMT 2000) in 2001. With further developments in the mobile communication technology, the technology for antennas also saw drastic advancements. As the mobile antennas moved from the second to the third generation, they grew from external models to very small internal models. At the same time, they evolved into highly functional and high performance multiple band and wide band antennas. Furthermore, Korea was the first country to commercialize and offer the Wireless Broadband Internet (WiBro) service in 2006. By leading the wireless communications standardization and exerting remarkable efforts in research and development, Korea is consolidating its status as an Information Technology (IT) leader in the global market. The antenna's inherent importance will be further emphasized in the near future as it satisfies the performance and structural needs of portable terminals necessary for realizing the projected establishment of the ubiquitous world. It is thought that antenna technologies will not be limited to simple concepts as previously experienced but will utilize various kinds

Dual polarized receiving steering antenna array for measurement of ultrawideband pulse polarization structure

Energy Technology Data Exchange (ETDEWEB)

Balzovsky, E. V.; Buyanov, Yu. I.; Koshelev, V. I., E-mail: koshelev@lhfe.hcei.tsc.ru; Nekrasov, E. S. [Institute of High Current Electronics SB RAS, IHCE SB RAS, Tomsk 634055 (Russian Federation)

2016-03-15

To measure simultaneously two orthogonal components of the electromagnetic field of nano- and subnano-second duration, an antenna array has been developed. The antenna elements of the array are the crossed dipoles of dimension 5 × 5 cm. The arms of the dipoles are connected to the active four-pole devices to compensate the frequency response variations of a short dipole in the frequency band ranging from 0.4 to 4 GHz. The dipoles have superimposed phase centers allowing measuring the polarization structure of the field in different directions. The developed antenna array is the linear one containing four elements. The pattern maximum position is controlled by means of the switched ultrawideband true time delay lines. Discrete steering in seven directions in the range from −40° to +40° has been realized. The error at setting the pattern maximum position is less than 4°. The isolation of the polarization exceeds 29 dB in the direction orthogonal to the array axis and in the whole steering range it exceeds 23 dB. Measurement results of the polarization structure of radiated and scattered pulses with different polarization are presented as well.

A flexible WLAN receiver

NARCIS (Netherlands)

Schiphorst, Roelof; Hoeksema, F.W.; Slump, Cornelis H.

2003-01-01

Flexible radio receivers are also called Software Defined Radios (SDRs) [1], [2]. The focus of our SDR project [3] is on designing the front end, from antenna to demodulation in bits, of a °exible, multi-standard WLAN receiver. We try to combine an instance of a (G)FSK receiver (Bluetooth) with an

Tx-Rx Isolation Exploiting Tunable Balanced-Unbalanced Antennas Architecture

DEFF Research Database (Denmark)

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

2012-01-01

The duplex filter is probably still the most expensive component in mobile handsets for the significant Transmitter (Tx) — Receiver (Rx) isolation required. This paper suggests to relax or even replace the duplex filter by equipping the Tx and the Rx with two separate antennas. The two antennas a...

LTE Radiated Data Throughput Measurements, Adopting MIMO 2x2 Reference Antennas

DEFF Research Database (Denmark)

Szini, Istvan Janos; Pedersen, Gert Frølund; Barrio, Samantha Caporal Del

2012-01-01

Long Term Evolution (LTE) requires Multiple Input Multiple Output (MIMO) antenna systems. Consequently a new over-the-air (OTA) test methodology need to be created to make proper assessment of LTE devices radiated performance. The antenna specific parameters i.e. total antenna efficiency, gain...... imbalance and correlation coefficient, are essential for a proper MIMO antenna system design. However it can't be use directly to assess the LTE device system performance, since a multiplicity of other factors are involved, e.g. power amplifier load- pull, low noise amplifier source-pull, self interference...... noise, baseband algorithm and other factors. Several standard organizations are working towards a consensus over the proper OTA MIMO test method, however so far results of measurement campaigns have ambiguous results not allowing a desirable progress [1]. Initially presented at one of several MIMO OTA...

A Rectangular Planar Spiral Antenna for GIS Partial Discharge Detection

Directory of Open Access Journals (Sweden)

Xiaoxing Zhang

2014-01-01

Full Text Available A rectangular planar spiral antenna sensor was designed for detecting the partial discharge in gas insulation substations (GIS. It can expediently receive electromagnetic waves leaked from basin-type insulators and can effectively suppress low frequency electromagnetic interference from the surrounding environment. Certain effective techniques such as rectangular spiral structure, bow-tie loading, and back cavity structure optimization during the antenna design process can miniaturize antenna size and optimize voltage standing wave ratio (VSWR characteristics. Model calculation and experimental data measured in the laboratory show that the antenna possesses a good radiating performance and a multiband property when working in the ultrahigh frequency (UHF band. A comparative study between characteristics of the designed antenna and the existing quasi-TEM horn antenna was made. Based on the GIS defect simulation equipment in the laboratory, partial discharge signals were detected by the designed antenna, the available quasi-TEM horn antenna, and the microstrip patch antenna, and the measurement results were compared.

Antenna Beam Pattern Characteristics of HAPS User Terminal

Science.gov (United States)

Ku, Bon-Jun; Oh, Dae Sub; Kim, Nam; Ahn, Do-Seob

High Altitude Platform Stations (HAPS) are recently considered as a green infrastructure to provide high speed multimedia services. The critical issue of HAPS is frequency sharing with satellite systems. Regulating antenna beam pattern using adaptive antenna schemes is one of means to facilitate the sharing with a space receiver for fixed satellite services on the uplink of a HAPS system operating in U bands. In this letter, we investigate antenna beam pattern characteristics of HAPS user terminals with various values of scan angles of main beam, null position angles, and null width.

An Approach for Smart Antenna Testbed

Science.gov (United States)

Kawitkar, R. S.; Wakde, D. G.

2003-07-01

The use of wireless, mobile, personal communications services are expanding rapidly. Adaptive or "Smart" antenna arrays can increase channel capacity through spatial division. Adaptive antennas can also track mobile users, improving both signal range and quality. For these reasons, smart antenna systems have attracted widespread interest in the telecommunications industry for applications to third generation wireless systems.This paper aims to design and develop an advanced antennas testbed to serve as a common reference for testing adaptive antenna arrays and signal combining algorithms, as well as complete systems. A flexible suite of off line processing software should be written using matlab to perform system calibration, test bed initialization, data acquisition control, data storage/transfer, off line signal processing and analysis and graph plotting. The goal of this paper is to develop low complexity smart antenna structures for 3G systems. The emphasis will be laid on ease of implementation in a multichannel / multi-user environment. A smart antenna test bed will be developed, and various state-of-the-art DSP structures and algorithms will be investigated.Facing the soaring demand for mobile communications, the use of smart antenna arrays in mobile communications systems to exploit spatial diversity to further improve spectral efficiency has recently received considerable attention. Basically, a smart antenna array comprises a number of antenna elements combined via a beamforming network (amplitude and phase control network). Some of the benefits that can be achieved by using SAS (Smart Antenna System) include lower mobile terminal power consumption, range extension, ISI reduction, higher data rate support, and ease of integration into the existing base station system. In terms of economic benefits, adaptive antenna systems employed at base station, though increases the per base station cost, can increase coverage area of each cell site, thereby reducing

Response functions of free mass gravitational wave antennas

Science.gov (United States)

Estabrook, F. B.

1985-01-01

The work of Gursel, Linsay, Spero, Saulson, Whitcomb and Weiss (1984) on the response of a free-mass interferometric antenna is extended. Starting from first principles, the earlier work derived the response of a 2-arm gravitational wave antenna to plane polarized gravitational waves. Equivalent formulas (generalized slightly to allow for arbitrary elliptical polarization) are obtained by a simple differencing of the '3-pulse' Doppler response functions of two 1-arm antennas. A '4-pulse' response function is found, with quite complicated angular dependences for arbitrary incident polarization. The differencing method can as readily be used to write exact response functions ('3n+1 pulse') for antennas having multiple passes or more arms.

Ultra-wideband horn antenna with abrupt radiator

Science.gov (United States)

McEwan, Thomas E.

1998-01-01

An ultra-wideband horn antenna transmits and receives impulse waveforms for short-range radars and impulse time-of flight systems. The antenna reduces or eliminates various sources of close-in radar clutter, including pulse dispersion and ringing, sidelobe clutter, and feedline coupling into the antenna. Dispersion is minimized with an abrupt launch point radiator element; sidelobe and feedline coupling are minimized by recessing the radiator into a metallic horn. Low frequency cut-off associated with a horn is extended by configuring the radiator drive impedance to approach a short circuit at low frequencies. A tapered feed plate connects at one end to a feedline, and at the other end to a launcher plate which is mounted to an inside wall of the horn. The launcher plate and feed plate join at an abrupt edge which forms the single launch point of the antenna.

Advanced Communication Technology Satellite (ACTS) multibeam antenna technology verification experiments

Science.gov (United States)

Acosta, Roberto J.; Larko, Jeffrey M.; Lagin, Alan R.

1992-01-01

The Advanced Communication Technology Satellite (ACTS) is a key to reaching NASA's goal of developing high-risk, advanced communications technology using multiple frequency bands to support the nation's future communication needs. Using the multiple, dynamic hopping spot beams, and advanced on board switching and processing systems, ACTS will open a new era in communications satellite technology. One of the key technologies to be validated as part of the ACTS program is the multibeam antenna with rapidly reconfigurable hopping and fixed spot beam to serve users equipped with small-aperature terminals within the coverage areas. The proposed antenna technology experiments are designed to evaluate in-orbit ACTS multibeam antenna performance (radiation pattern, gain, cross pol levels, etc.).

Antenna-coupled bolometer arrays using transition-edge sensors

Energy Technology Data Exchange (ETDEWEB)

Myers, Michael J. [Department of Physics, University of California, Berkeley, California 94720 (United States)]. E-mail: mmyers@cosmology.berkeley.edu; Ade, Peter [School of Physics and Astronomy, Cardiff University, Cardiff, Wales (United Kingdom); Arnold, Kam [Department of Physics, University of California, Berkeley, California 94720 (United States); Engargiola, Greg [Department of Astronomy, University of California, Berkeley, California 94720 (United States); Holzapfel, Bill [Department of Physics, University of California, Berkeley, California 94720 (United States); Lee, Adrian T. [Department of Physics, University of California, Berkeley, California 94720 (United States); O' Brient, Roger [Department of Physics, University of California, Berkeley, California 94720 (United States); Richards, Paul L. [Department of Physics, University of California, Berkeley, California 94720 (United States); Smith, Andy [Northrop Grumman, Redondo Beach, California 90278 (United States); Spieler, Helmuth [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Tran, Huan T. [Department of Physics, University of California, Berkeley, California 94720 (United States)

2006-04-15

We are developing antenna-coupled Transition-Edge Sensor (TES) bolometer arrays for use in measurements of the CMB polarization. TES bolometers have many well-known advantages over conventional bolometers, such as increased speed, linearity, and the existence of readout multiplexers. Antenna-coupled bolometers use an on-chip planar antenna to couple light into the bolometer. The antenna directivity and polarization sensitivity, along with the potential for on-chip band defining filters and channelizing circuits, allow a significant increase in focal plane integration. This eliminates the bulky horns, quasioptical filters, dichroics, and polarizers which might otherwise be needed in a conventional bolometric system. This simplification will ease the construction of receivers with larger numbers of pixels. We report on the fabrication and optical testing of single antenna-coupled bolometer pixels with integrated band defining filters. We will also discuss current progress on fabrication of a bolometer array based on this design.

Planar Submillimeter-Wave Mixer Technology with Integrated Antenna

Science.gov (United States)

Chattopadhyay, Gautam; Mehdi, Imran; Gill, John J.; Lee, Choonsup; lombart, Muria L.; Thomas, Betrand

2010-01-01

High-performance mixers at terahertz frequencies require good matching between the coupling circuits such as antennas and local oscillators and the diode embedding impedance. With the availability of amplifiers at submillimeter wavelengths and the need to have multi-pixel imagers and cameras, planar mixer architecture is required to have an integrated system. An integrated mixer with planar antenna provides a compact and optimized design at terahertz frequencies. Moreover, it leads to a planar architecture that enables efficient interconnect with submillimeter-wave amplifiers. In this architecture, a planar slot antenna is designed on a thin gallium arsenide (GaAs) membrane in such a way that the beam on either side of the membrane is symmetric and has good beam profile with high coupling efficiency. A coplanar waveguide (CPW) coupled Schottky diode mixer is designed and integrated with the antenna. In this architecture, the local oscillator (LO) is coupled through one side of the antenna and the RF from the other side, without requiring any beam sp litters or diplexers. The intermediate frequency (IF) comes out on a 50-ohm CPW line at the edge of the mixer chip, which can be wire-bonded to external circuits. This unique terahertz mixer has an integrated single planar antenna for coupling both the radio frequency (RF) input and LO injection without any diplexer or beamsplitters. The design utilizes novel planar slot antenna architecture on a 3- mthick GaAs membrane. This work is required to enable future multi-pixel terahertz receivers for astrophysics missions, and lightweight and compact receivers for planetary missions to the outer planets in our solar system. Also, this technology can be used in tera hertz radar imaging applications as well as for testing of quantum cascade lasers (QCLs).

Minimizing Detection Probability Routing in Ad Hoc Networks Using Directional Antennas

Directory of Open Access Journals (Sweden)

Towsley Don

2009-01-01

Full Text Available In a hostile environment, it is important for a transmitter to make its wireless transmission invisible to adversaries because an adversary can detect the transmitter if the received power at its antennas is strong enough. This paper defines a detection probability model to compute the level of a transmitter being detected by a detection system at arbitrary location around the transmitter. Our study proves that the probability of detecting a directional antenna is much lower than that of detecting an omnidirectional antenna if both the directional and omnidirectional antennas provide the same Effective Isotropic Radiated Power (EIRP in the direction of the receiver. We propose a Minimizing Detection Probability (MinDP routing algorithm to find a secure routing path in ad hoc networks where nodes employ directional antennas to transmit data to decrease the probability of being detected by adversaries. Our study shows that the MinDP routing algorithm can reduce the total detection probability of deliveries from the source to the destination by over 74%.

Multi-Layer 5G Mobile Phone Antenna for Multi-User MIMO Communications

DEFF Research Database (Denmark)

Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.

2015-01-01

for 5G wireless communications. Two identical linear sub arrays can be simultaneously used at different sides of the mobile-phone printed circuit board (PCB) for operation in diversity or multiple-input multiple-output (MIMO) modes. Each sub array contains eight elements of very compact off......-center dipole antennas with dimensions of 5.4×0.67 mm2. The feature of compact design with good beam-steering function makes them well-suited to integrate into the mobile-phone mock-up. The fundamental properties of the proposed antenna have been investigated. Simulations show that the proposed 5G antenna......In this study, a new design of multi-layer phased array antenna for millimeter-wave (mm-Wave) fifth generation (5G) mobile terminals is proposed. The proposed linear phased array antenna is designed on four layers of the Rogers RT5880 substrates to operate at 28 GHz which is under consideration...

Plasma antennas: dynamically configurable antennas for communications

International Nuclear Information System (INIS)

Borg, G.; Harris, J.

1999-01-01

In recent years, the rapid growth in both communications and radar systems has led to a concomitant growth in the possible applications and requirements of antennas. These new requirements include compactness and conformality, rapid reconfigurability for directionality and frequency agility. For military applications, antennas should also allow low absolute or out-of-band radar cross-section and facilitate low probability of intercept communications. Investigations have recently begun worldwide on the use of ionised gases or plasmas as the conducting medium in antennas that could satisfy these requirements. Such plasma antennas may even offer a viable alternative to metal in existing applications when overall technical requirements are considered. A recent patent for ground penetrating radar claims the invention of a plasma antenna for the transmission of pulses shorter than 100 ns in which it is claimed that current ringing is avoided and signal processing simplified compared with a metal antenna. A recent US ONR tender has been issued for the design and construction of a compact and rapidly reconfigurable antenna for dynamic signal reception over the frequency range 1 - 45 GHz based on plasma antennas. Recent basic physics experiments at ANU have demonstrated that plasma antennas can attain adequate efficiency, predictable radiation patterns and low base-band noise for HF and VHF communications. In this paper we describe the theory of the low frequency plasma antenna and present a few experimental results

Utilization of antenna arrays in HF systems

Directory of Open Access Journals (Sweden)

Louis Bertel

2009-06-01

Full Text Available

Different applications of radio systems are based on the implementation of antenna arrays. Classically, radio direction

finding operates with a multi channel receiving system connected to an array of receiving antennas. More

recently, MIMO architectures have been proposed to increase the capacity of radio links by the use of antenna

arrays at both the transmitter and receiver.

The first part of this paper describes some novel experimental work carried out to examine the feasibility of applying

MIMO techniques for communications within the HF radio band. A detailed correlation analysis of a variety

of different antenna array configurations is presented. The second section of the paper also deals with HF

MIMO communications, focusing on the problem from a modelling point of view. The third part presents a sensitivity

analysis of different antenna array structures for HF direction finding applications. The results demonstrate

that when modelling errors, heterogeneous antenna arrays are more robust in comparison to homogeneous structures

Comments on "On the Power Absorbed and Scattered by an Antenna"

Czech Academy of Sciences Publication Activity Database

Schejbal, V.; Fišer, Ondřej; Ondráček, O.

2011-01-01

Roč. 53, č. 2 (2011), s. 172-174 ISSN 1045-9243 Institutional research plan: CEZ:AV0Z30420517 Keywords : Antennas * antenna theory * receiving antennas * electromagnetic scattering * antenna scattering Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.968, year: 2011 http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F74%2F5949312%2F05949355.pdf%3Ftp%3D%26arnumber%3D5949355%26punumber%3D74&authDecision=-203

An Integrated 4-element Slot-Based MIMO and an UWB Sensing Antenna System for CR Platforms

KAUST Repository

Hussain, Rifaqat; Sharawi, Mohammad S.; Shamim, Atif

2017-01-01

This paper presents a novel integrated antenna system for cognitive radio (CR) applications. The design consists of a compact 4- element reconfigurable annular slot based multiple-input-multiple-output (MIMO) antenna system integrated within an ultra-wide-band (UWB) sensing antenna. All the antenna elements are planar in structure and designed on a single substrate (RO-4350) with dimensions 60×120×1.5 mm3. The frequency reconfigurable slot based MIMO antenna system is tuned over a wide frequency band from 1.77 GHz to 2.51 GHz while the UWB sensing antenna is covering from 0.75~7.65 GHz The proposed antenna system is suitable for CR enabled wireless devices. The envelope correlation coefficient (ECC) did not exceed 0.248 in the entire operating band of the MIMO antenna part. The maximum measured gain of the MIMO antenna is 3.2 dBi with maximum efficiency of 81%.

An Integrated 4-element Slot-Based MIMO and an UWB Sensing Antenna System for CR Platforms

KAUST Repository

Hussain, Rifaqat

2017-12-08

This paper presents a novel integrated antenna system for cognitive radio (CR) applications. The design consists of a compact 4- element reconfigurable annular slot based multiple-input-multiple-output (MIMO) antenna system integrated within an ultra-wide-band (UWB) sensing antenna. All the antenna elements are planar in structure and designed on a single substrate (RO-4350) with dimensions 60×120×1.5 mm3. The frequency reconfigurable slot based MIMO antenna system is tuned over a wide frequency band from 1.77 GHz to 2.51 GHz while the UWB sensing antenna is covering from 0.75~7.65 GHz The proposed antenna system is suitable for CR enabled wireless devices. The envelope correlation coefficient (ECC) did not exceed 0.248 in the entire operating band of the MIMO antenna part. The maximum measured gain of the MIMO antenna is 3.2 dBi with maximum efficiency of 81%.

DUAL POLARIZATION ANTENNA ARRAY WITH VERY LOW CROSS POLARIZATION AND LOW SIDE LOBES

DEFF Research Database (Denmark)

1997-01-01

The present invention relates to an antenna array adapted to radiate or receive electromagnetic waves of one or two polarizations with very low cross polarization and low side lobes. An antenna array comprising many antenna elements, e.g. more than ten antenna elements, is provided in which...... formation of grating lobes are inhibited in selected directions of the radiation and cross polarization within the main lobe is suppressed at least 30 dB below the main lobe peak value. According to a preferred embodiment of the invention, the antenna elements of the antenna array comprise probe-fed patches...

Multichannel microwave interferometer with an antenna switching system for electron density measurement in a laboratory plasma experiment

Energy Technology Data Exchange (ETDEWEB)

Kawamori, Eiichirou; Lin, Yu-Hsiang [Institute of Space and Plasma Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China); Mase, Atsushi [Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga 816-8580 (Japan); Nishida, Yasushi; Cheng, C. Z. [Institute of Space and Plasma Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China); Plasma and Space Science Center, National Cheng Kung University, Tainan 70101, Taiwan (China)

2014-02-15

This study presents a simple and powerful technique for multichannel measurements of the density profile in laboratory plasmas by microwave interferometry. This technique uses electromechanical microwave switches to temporally switch the connection between multiple receiver antennas and one phase-detection circuit. Using this method, the phase information detected at different positions is rearranged into a time series that can be acquired from a minimum number of data acquisition channels (e.g., two channels in the case of quadrature detection). Our successfully developed multichannel microwave interferometer that uses the antenna switching method was applied to measure the radial electron density profiles in a magnetized plasma experiment. The advantage of the proposed method is its compactness and scalability to multidimensional measurement systems at low cost.

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

Distributed Antenna Channels with Regenerative Relaying: Relay Selection and Asymptotic Capacity

Directory of Open Access Journals (Sweden)

Aitor del Coso

2007-11-01

Full Text Available Multiple-input-multiple-output (MIMO techniques have been widely proposed as a means to improve capacity and reliability of wireless channels, and have become the most promising technology for next generation networks. However, their practical deployment in current wireless devices is severely affected by antenna correlation, which reduces their impact on performance. One approach to solve this limitation is relaying diversity. In relay channels, a set of N wireless nodes aids a source-destination communication by relaying the source data, thus creating a distributed antenna array with uncorrelated path gains. In this paper, we study this multiple relay channel (MRC following a decode-and-forward (D&F strategy (i.e., regenerative forwarding, and derive its achievable rate under AWGN. A half-duplex constraint on relays is assumed, as well as distributed channel knowledge at both transmitter and receiver sides of the communication. For this channel, we obtain the optimum relay selection algorithm and the optimum power allocation within the network so that the transmission rate is maximized. Likewise, we bound the ergodic performance of the achievable rate and derive its asymptotic behavior in the number of relays. Results show that the achievable rate of regenerative MRC grows as the logarithm of the Lambert W function of the total number of relays, that is, 𝒞=log⁡2(W0(N. Therefore, D&F relaying, cannot achieve the capacity of actual MISO channels.

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.

Performance Analysis of Receive Diversity in Wireless Sensor Networks over GBSBE Models

OpenAIRE

Goel, Shivali; Abawajy, Jemal H.; Kim, Tai-hoon

2010-01-01

Wireless sensor networks have attracted a lot of attention recently. In this paper, we develop a channel model based on the elliptical model for multipath components involving randomly placed scatterers in the scattering region with sensors deployed on a field. We verify that in a sensor network, the use of receive diversity techniques improves the performance of the system. Extensive performance analysis of the system is carried out for both single and multiple antennas with the applied rece...

'Chaos' in superregenerative receivers

International Nuclear Information System (INIS)

Commercon, Jean-Claude; Badard, Robert

2005-01-01

The superregenerative principle has been known since the early 1920s. The circuit is extremely simple and extremely sensitive. Today, superheterodyne receivers generally supplant superregenerative receivers in most applications because there are several undesirable characteristics: poor selectivity, reradiation, etc. Superregenerative receivers undergo a revival in recent papers for wireless systems, where low cost and very low power consumption are relevant: house/building meters (such as water, energy, gas counter), personal computer environment (keyboard, mouse), etc. Another drawback is the noise level which is higher than that of a well-designed superheterodyne receiver; without an antenna input signal, the output of the receiver hears in an earphone as a waterfall noise; this sound principally is the inherent input noise amplified and detected by the circuit; however, when the input noise is negligible with respect of an antenna input signal, we are faced to an other source of 'noise' self-generated by the superregenerative working. The main objective of this paper concerns this self-generated noise coming from an exponential growing followed by a re-injection process for which the final state is a function of the phase of the input signal

Advanced Communication Technology Satellite (ACTS) multibeam antenna analysis and experiment

Science.gov (United States)

Acosta, Roberto J.; Lagin, Alan R.; Larko, Jeffrey M.; Narvaez, Adabelle

1992-01-01

One of the most important aspects of a satellite communication system design is the accurate estimation of antenna performance degradation. Pointing error, end coverage gain, peak gain degradation, etc. are the main concerns. The thermal or dynamic distortions of a reflector antenna structural system can affect the far-field antenna power distribution in a least four ways. (1) The antenna gain is reduced; (2) the main lobe of the antenna can be mispointed thus shifting the destination of the delivered power away from the desired locations; (3) the main lobe of the antenna pattern can be broadened, thus spreading the RF power over a larger area than desired; and (4) the antenna pattern sidelobes can increase, thus increasing the chances of interference among adjacent beams of multiple beam antenna system or with antenna beams of other satellites. The in-house developed NASA Lewis Research Center thermal/structural/RF analysis program was designed to accurately simulate the ACTS in-orbit thermal environment and predict the RF antenna performance. The program combines well establish computer programs (TRASYS, SINDA and NASTAN) with a dual reflector-physical optics RF analysis program. The ACTS multibeam antenna configuration is analyzed and several thermal cases are presented and compared with measurements (pre-flight).

A Novel Approach to Beam Steering Using Arrays Composed of Multiple Unique Radiating Modes

Science.gov (United States)

Labadie, Nathan Richard

Phased array antennas have found wide application in both radar and wireless communications systems particularly as implementation costs continue to decrease. The primary advantages of electronically scanned arrays are speed of beam scan and versatility of beamforming compared to mechanically scanned fixed beam antennas. These benefits come at the cost of a few well known design issues including element pattern rolloff and mutual coupling between elements. Our primary contribution to the field of research is the demonstration of significant improvement in phased array scan performance using multiple unique radiating modes. In short, orthogonal radiating modes have minimal coupling by definition and can also be generated with reduced rolloff at wide scan angles. In this dissertation, we present a combination of analysis, full-wave electromagnetic simulation and measured data to support our claims. The novel folded ring resonator (FRR) antenna is introduced as a wideband and multi-band element embedded in a grounded dielectric substrate. Multiple radiating modes of a small ground plane excited by a four element FRR array were also investigated. A novel hemispherical null steering antenna composed of two collocated radiating elements, each supporting a unique radiating mode, is presented in the context of an anti-jam GPS receiver application. Both the antenna aperture and active feed network were fabricated and measured showing excellent agreement with analytical and simulated data. The concept of using an antenna supporting multiple radiating modes for beam steering is also explored. A 16 element hybrid linear phased array was fabricated and measured demonstrating significantly improved scan range and scanned gain compared to a conventional phased array. This idea is expanded to 2 dimensional scanning arrays by analysis and simulation of a hybrid phased array composed of novel multiple mode monopole on patch antenna sub-arrays. Finally, we fabricated and

Satellite Antenna Pointing Procedure Driven by the Ground Service Quality

Science.gov (United States)

Yasui, Yoshitsugu

A satellite antenna alignment technique is proposed to ensure terrestrial service quality for users. The antenna bore sight orientation is calculated directly from measured data acquired from general ground receivers, which intercept the communication radio waves from any position on the earth's surface. The method coordinates the satellite pointing parameters with signal strength at the receivers while considering location-specific geographical and antenna radiation characteristics and control accuracy. The theoretical development and its validity are examined in the course of equation derivation. Actual measured data of an existing satellite at the maneuver was applied to the method, and the capability was demonstrated and verified. With the wide diversity of satellite usage, such as for mobile communications, temporary network deployment or post-launch positioning accommodations, the proposed method provides a direct evaluation of satellite communication performance at the service level, in conjunction with using high frequency spot beam antennas, which are highly susceptible to pointing gain. This can facilitate swift and flexible satellite service planning and deployment for operators.

High-performance low-power smart antenna for smart world applications

CSIR Research Space (South Africa)

Lysko, AA

2014-10-01

Full Text Available with the summary in Section IV. II. ANTENNA SYSTEM DESCRIPTION The antenna introduced in this paper is an advanced and compact array antenna-based system which sends/receives the signals into/from the air, with the direction of transmission/reception being... of radiation pattern. The optimization variables were the height of the antenna’s active and parasitic elements and the radius at which the parasitic elements are away from the active element. The manufactured prototype is shown in Fig. 1b. It is compact...

Low profile frequency agile MIMO slot antenna with TCM characterization

KAUST Repository

Ghalib, Asim

2017-06-07

In this paper, a frequency reconfigurable multiple-input-multiple-output (MIMO) slot antenna is presented. The proposed design is low profile and compact with wide tunability range, covering several well-known frequency bands from 1800 MHz to 2450 MHz. The frequency reconfigurability is achieved by loading the annular slot with varactor diodes. The antenna system is also analyzed for MIMO performance metrics. Moreover, the effect of circular slot antenna on the chassis modes is also investigated using the theory of characteristic modes (TCM). The physical principle behind frequency reconfigurability is also investigated using TCM analysis. An interesting finding is observed using varactor diodes for frequency reconfigurability, that is the reactive impedance loading does not alter the modal significance (MS) plots but only aid in the input impedance matching at different frequency bands.

Transmit selection algorithms for imperfect threshold-based receive MRC in the presence of co-channel interference

KAUST Repository

Radaydeh, Redha Mahmoud Mesleh

2010-01-01

The performance of transmit antenna selection for threshold-based maximal ratio combining (MRC) diversity receivers in the presence of multiple co-channel interfering signals is studied. The impact of imperfect channel estimation of desired user signals is considered, and the effect of phase and time misalignments between desired and undesired signals is incorporated in the analysis. Precise formulation for Nakagami-m faded interfering signals is presented. The analysis is applicable for arbitrary transmit antenna selection, which is based on the receiver combined signal-to-noise ratios (SNRs) or combined signal-to-interference-plus-noise ratios (SINRs) for different transmit channels. New expressions for the distribution of combined SINR and outage probability performance are derived considering SNR-based as well as SINR-based selection algorithms. The results can be used to study the performance of different system architectures under various channel conditions when the implementation complexity is of interest. ©2010 IEEE.

Integrated, Dual Orthogonal Antennas for Polarimetric Ground Penetrating Radar

Science.gov (United States)

Pauli, Mario; Wiesbeck, Werner

2015-04-01

Ground penetrating radar systems are mostly equipped with single polarized antennas, for example with single linear polarization or with circular polarization. The radiated waves are partly reflected at the ground surface and very often the penetrating waves are distorted in their polarization. The distortion depends on the ground homogeneity and the orientation of the antennas relative to the ground structure. The received signals from the reflecting objects may most times only be classified according to their coverage and intensity. This makes the recognition of the objects difficult or impossible. In airborne and spaceborne Remote Sensing the systems are meanwhile mostly equipped with front ends with dual orthogonal polarized antennas for a full polarimetric operation. The received signals, registered in 2x2 scattering matrices according to co- and cross polarization, are processed for the evaluation of all features of the targets. Ground penetrating radars could also profit from the scientific results of Remote Sensing. The classification of detected objects for their structure and orientation requires more information in the reflected signal than can be measured with a single polarization [1, 2]. In this paper dual linear, orthogonal polarized antennas with a common single, frequency independent phase center, are presented [3]. The relative bandwidth of these antennas can be 1:3, up to 1:4. The antenna is designed to work in the frequency range between 3 GHz and 11 GHz, but can be easily adapted to the GPR frequency range by scaling. The size of the antenna scaled for operation in typical GPR frequencies would approximately be 20 by 20 cm2. By the implementation in a dielectric carrier it could be reduced in size if required. The major problem for ultra wide band, dual polarized antennas is the frequency independent feed network, realizing the required phase shifts. For these antennas a network, which is frequency independent over a wide range, has been

An overview of Test Techniques for Characterizing Active Phased Array Antennas

NARCIS (Netherlands)

Keizer, W.P.M.N.

1999-01-01

In this paper a review will be given of the microwave testing of active phased anay antennas. It will be shown that due to the application of Transmit/Receive (T/R) modules in such antennas considerable more tests have to be performed to characterise completely their microwave performance than for

Investigation of Vertical Microwave Publishing Caused by the Base Transceiver Station (BTS Antennas in Hashtgerd City

Directory of Open Access Journals (Sweden)

Simin Naseri

2013-12-01

Full Text Available Background and Objectives: New Hazards interface the environment and human life along with technology development. One of these pollutants is electromagnetic field and it’s known and unknown bad effects on the environment, this study determines the vertical publishing (height measurement of microwave antennas in the city of Hashtgerd. Methods: The basic information including the geographical location of the BTS antennas in the city, brand, the operator type, installation and its height was received from CRA and radio communications, and then the measuring was done by using the standard method of IEEE STD 95. 1 by the SPECTRAN 4060, and by using crane elevator in 17-meters height near the BTS antennas (15 meters.analysis were done by Spss16 and by Kolmogorov Smirnov test, multiple regression method. Results: Results show that in the both operators of Irancell and Hamrah-e-aval, density will increase by increasing measurement height or decreasing the vertical distance of broadcaster antenna. Regarding to the mix model test, a meaningful statistical relationship can be seen between measurement height and the density average in both types of the operators. Conclusion: while measuring height increased or in other words got closer to the antennas, density average increased in both operators, so the highest number was reported in the minimum vertical distance compared to the Irancell operator antenna was 25 mw/m2 and the lowest number was related to Hamrah-e-aval operator in the maximum vertical distance which was 0.02mw/m2. Thus, people stationed in the tall buildings parallel with installation height of antennas or in less vertical distance of them, are more exposed to the waves.

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

Distributed Antenna Systems (DAS) is one of the most promising ways of network deployment now-a-days. Mostly it is used in indoor environment for shopping areas and office locations. Here the Outdoor application of DAS, where multiple service providers can install their Base Transceiver Station...... (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...

Microwave Ablation: Comparison of Simultaneous and Sequential Activation of Multiple Antennas in Liver Model Systems.

Science.gov (United States)

Harari, Colin M; Magagna, Michelle; Bedoya, Mariajose; Lee, Fred T; Lubner, Meghan G; Hinshaw, J Louis; Ziemlewicz, Timothy; Brace, Christopher L

2016-01-01

To compare microwave ablation zones created by using sequential or simultaneous power delivery in ex vivo and in vivo liver tissue. All procedures were approved by the institutional animal care and use committee. Microwave ablations were performed in both ex vivo and in vivo liver models with a 2.45-GHz system capable of powering up to three antennas simultaneously. Two- and three-antenna arrays were evaluated in each model. Sequential and simultaneous ablations were created by delivering power (50 W ex vivo, 65 W in vivo) for 5 minutes per antenna (10 and 15 minutes total ablation time for sequential ablations, 5 minutes for simultaneous ablations). Thirty-two ablations were performed in ex vivo bovine livers (eight per group) and 28 in the livers of eight swine in vivo (seven per group). Ablation zone size and circularity metrics were determined from ablations excised postmortem. Mixed effects modeling was used to evaluate the influence of power delivery, number of antennas, and tissue type. On average, ablations created by using the simultaneous power delivery technique were larger than those with the sequential technique (P Simultaneous ablations were also more circular than sequential ablations (P = .0001). Larger and more circular ablations were achieved with three antennas compared with two antennas (P simultaneous power delivery creates larger, more confluent ablations with greater temperatures than those created with sequential power delivery. © RSNA, 2015.

Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

Science.gov (United States)

Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

2014-01-01

This presentation discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 2x4 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and 4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to- ground communication links with enough channel capacity to support voice, data and video links from CubeSats, unmanned air vehicles (UAV), and commercial aircraft.

Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

Science.gov (United States)

Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

2014-01-01

This paper discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 4x2 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and pi/4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to-ground communication links with enough channel capacity to support voice, data and video links from cubesats, unmanned air vehicles (UAV), and commercial aircraft.

A Blind Antenna Selection Scheme for Single-Cell Uplink Massive MIMO

KAUST Repository

Elkhalil, Khalil

2017-02-09

This paper considers the uplink of a single-cell large-scale multiple-input multiple output (MIMO) system in which m mono-antenna users communicate with a base station (BS) outfitted by n antennas. We assume that the number of antennas at the BS and that of users take large values, as envisioned by large-scale MIMO systems. This allows for high spectral efficiency gains but obviously comes at the cost of higher complexity, a fact that becomes all the more critical as the number of antennas grows large. To solve this issue is to choose a subset of the available n antennas. The subset must be carefully chosen to achieve the best performance. However, finding the optimal subset of antennas is usually a difficult task, requiring one to solve a high dimensional combinatorial optimization problem. In this paper, we approach this problem in two ways. The first one consists in solving a convex relaxation of the problem using standard convex optimization tools. The second technique solves the problem using a greedy approach. The main advantages of the greedy approach lies in its wider scope, in that, unlike the first approach, it can be applied irrespective of the considered performance criterion. As an outcome of this feature, we show that the greedy approach can be applied even when only the channel statistics are available at the BS, which provides blind way to perform antenna selection.

The phase accumulation and antenna near field of microscopic propagating spin wave devices

Energy Technology Data Exchange (ETDEWEB)

Chang, Crosby S.; Kostylev, Mikhail, E-mail: mikhail.kostylev@uwa.edu.au; Ivanov, Eugene [School of Physics M013, The University of Western Australia, Crawley, WA 6009 (Australia); Ding, Junjia; Adeyeye, Adekunle O. [Department of Electrical and Computer Engineering, National University of Singapore, 117576 Singapore (Singapore)

2014-01-20

We studied phase accumulation by the highly non-reciprocal magnetostatic surface spin waves in thin Permalloy microstripes excited and received by microscopic coplanar antennae. We find that the experimentally measured characteristic length of the near field of the antenna is smaller than the total width of the coplanar. This is confirmed by our numerical simulations. Consequently, the distance over which the spin wave accumulates its phase while travelling between the input and output antennae coincides with the distance between the antennae symmetry axes with good accuracy.

The phase accumulation and antenna near field of microscopic propagating spin wave devices

International Nuclear Information System (INIS)

Chang, Crosby S.; Kostylev, Mikhail; Ivanov, Eugene; Ding, Junjia; Adeyeye, Adekunle O.

2014-01-01

We studied phase accumulation by the highly non-reciprocal magnetostatic surface spin waves in thin Permalloy microstripes excited and received by microscopic coplanar antennae. We find that the experimentally measured characteristic length of the near field of the antenna is smaller than the total width of the coplanar. This is confirmed by our numerical simulations. Consequently, the distance over which the spin wave accumulates its phase while travelling between the input and output antennae coincides with the distance between the antennae symmetry axes with good accuracy

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.

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

Monostatic ultra-wideband GPR antenna for through wall detection

Directory of Open Access Journals (Sweden)

Ali Jawad

2017-01-01

Full Text Available The aim of this paper is to present a monostatic arc-shaped ultra-wideband (UWB printed monopole antenna system with 3-16 GHz frequency bandwidth suitable for through-wall detection. Ground penetrating radar (GPR technique is used for detection with the gain of 6.2 dB achieved for the proposed antenna using defected ground structure (DGS method. To serve the purpose, a simulation experiment of through-wall detection model is constructed which consists of a monostatic antenna act as transmitter and receiver, concrete wall and human skin model. The time domain reflection of obtained result is then analysed for target detection.

Dual Band Planar Inverted F Antenna (PIFA with L-Shape Configuration

Directory of Open Access Journals (Sweden)

khlouf Munzer Mohamad

2017-01-01

Full Text Available One of the most used antennas in mobile devices is planar inverted F antenna (PIFA. PIFA can be design in dual band frequencies due to the coverage of the wireless service in a mobile device that requires a multiple frequencies. However, the consideration of technical operation has to be combined with an evaluation of the antenna radiation impact on the users. A procedure of PIFA work in GSM (867-960MHz and GSM (1710-1899MHz is done using CST Software. The dual band frequency response is obtained by means of an insertion of an L-shaped slot, which is use to tune the operation frequencies. The prototype of the antenna is fabricated as model by CST Software and evaluated. It is found out that the PIFA antenna has a good efficiency, bandwidth as well as produce a maximum gain for the antenna. A key and innovative research is still underway to broaden performance parameters of the antenna.

Research on calibration error of carrier phase against antenna arraying

Science.gov (United States)

Sun, Ke; Hou, Xiaomin

2016-11-01

It is the technical difficulty of uplink antenna arraying that signals from various quarters can not be automatically aligned at the target in deep space. The size of the far-field power combining gain is directly determined by the accuracy of carrier phase calibration. It is necessary to analyze the entire arraying system in order to improve the accuracy of the phase calibration. This paper analyzes the factors affecting the calibration error of carrier phase of uplink antenna arraying system including the error of phase measurement and equipment, the error of the uplink channel phase shift, the position error of ground antenna, calibration receiver and target spacecraft, the error of the atmospheric turbulence disturbance. Discuss the spatial and temporal autocorrelation model of atmospheric disturbances. Each antenna of the uplink antenna arraying is no common reference signal for continuous calibration. So it must be a system of the periodic calibration. Calibration is refered to communication of one or more spacecrafts in a certain period. Because the deep space targets are not automatically aligned to multiplexing received signal. Therefore the aligned signal should be done in advance on the ground. Data is shown that the error can be controlled within the range of demand by the use of existing technology to meet the accuracy of carrier phase calibration. The total error can be controlled within a reasonable range.

The short-term effects of antenna insulation thickness on path losses in wireless telemetry implants at microwave frequencies

Directory of Open Access Journals (Sweden)

Lukas Kneisz

2013-07-01

Full Text Available Various physiological parameters can be monitored non-invasively using wireless biotelemetry links. The development of sophisticated ultra low power consuming transceivers allows the transmission of large amounts of data from the inside of the body to an external receiver in real time at microwave frequencies.Antenna impedance matching is crucial for obtaining an acceptable propagation link budget in a wireless telemetry link. The dielectric properties of biological tissue induce detuning to transceiver antennas when implanted into the body. To counteract detuning problems, implant antennas are coated with biocompatible insulating material. The study investigates the propagation losses of a wireless communication link at different insulation thicknesses of medical grade silicone in the Industrial-Scientific-Medical (ISM radio band at 2.45 GHz. The wireless link consisted of an implantable unit which was placed between two pads of tissue substitute material and an external receiver which was connected to a laptop. Predefined data packets were transmitted from the implant, the received packets were analyzed, packet errors and packet losses were logged and the received signal strength indicator values (RSSI were recorded. Our results showed that the mean RSSI values of insulated transmitter antennas - embedded in tissue equivalent material - provide more safety distance to critical receiver sensitivity level than uncoated antennas.The conducted measurements let us conclude that with increasing thickness of the insulation layer, the antenna becomes less sensitive to detuning by adjacent tissue substitute material. Therefore tuned antennas are less influenced by the surrounding tissue after implantation.

Polarization Multiplexing of Fluorescent Emission Using Multiresonant Plasmonic Antennas.

Science.gov (United States)

De Leo, Eva; Cocina, Ario; Tiwari, Preksha; Poulikakos, Lisa V; Marqués-Gallego, Patricia; le Feber, Boris; Norris, David J; Prins, Ferry

2017-12-26

Combining the ability to localize electromagnetic fields at the nanoscale with a directional response, plasmonic antennas offer an effective strategy to shape the far-field pattern of coupled emitters. Here, we introduce a family of directional multiresonant antennas that allows for polarization-resolved spectral identification of fluorescent emission. The geometry consists of a central aperture surrounded by concentric polygonal corrugations. By varying the periodicity of each axis of the polygon individually, this structure can support multiple resonances that provide independent control over emission directionality for multiple wavelengths. Moreover, since each resonant wavelength is directly mapped to a specific polarization orientation, spectral information can be encoded in the polarization state of the out-scattered beam. To demonstrate the potential of such structures in enabling simplified detection schemes and additional functionalities in sensing and imaging applications, we use the central subwavelength aperture as a built-in nanocuvette and manipulate the fluorescent response of colloidal-quantum-dot emitters coupled to the multiresonant antenna.

On Secure NOMA Systems with Transmit Antenna Selection Schemes

KAUST Repository

Lei, Hongjiang; Zhang, Jianming; Park, Kihong; Xu, Peng; Ansari, Imran Shafique; Pan, Gaofeng; Alomair, Basel; Alouini, Mohamed-Slim

2017-01-01

This paper investigates the secrecy performance of a two-user downlink non-orthogonal multiple access systems. Both single-input and single-output and multiple-input and singleoutput systems with different transmit antenna selection (TAS) strategies are considered. Depending on whether the base station has the global channel state information of both the main and wiretap channels, the exact closed-form expressions for the secrecy outage probability (SOP) with suboptimal antenna selection and optimal antenna selection schemes are obtained and compared with the traditional space-time transmission scheme. To obtain further insights, the asymptotic analysis of the SOP in high average channel power gains regime is presented and it is found that the secrecy diversity order for all the TAS schemes with fixed power allocation is zero. Furthermore, an effective power allocation scheme is proposed to obtain the nonzero diversity order with all the TAS schemes. Monte-Carlo simulations are performed to verify the proposed analytical results.

On Secure NOMA Systems with Transmit Antenna Selection Schemes

KAUST Repository

Lei, Hongjiang

2017-08-09

This paper investigates the secrecy performance of a two-user downlink non-orthogonal multiple access systems. Both single-input and single-output and multiple-input and singleoutput systems with different transmit antenna selection (TAS) strategies are considered. Depending on whether the base station has the global channel state information of both the main and wiretap channels, the exact closed-form expressions for the secrecy outage probability (SOP) with suboptimal antenna selection and optimal antenna selection schemes are obtained and compared with the traditional space-time transmission scheme. To obtain further insights, the asymptotic analysis of the SOP in high average channel power gains regime is presented and it is found that the secrecy diversity order for all the TAS schemes with fixed power allocation is zero. Furthermore, an effective power allocation scheme is proposed to obtain the nonzero diversity order with all the TAS schemes. Monte-Carlo simulations are performed to verify the proposed analytical results.

A compact planar multi-broad band monopole antenna for mobile devices

Science.gov (United States)

Zhong, Xiaoqing; Yao, Bin; Zheng, Qinhong; Yang, Jikong; Cao, Xiangqi

2015-10-01

A Multiple-frequency broadband planar monopole antenna is proposed in this Paper. The antenna is stimulated and numerically optimized by HFSS13.0 (High Frequency Structure Simulator). The size of it is 39mm×22mm×1.7mm. The antenna resonates at many frequencies. The parameter S112G(DCS1800 and PCS1900), 3G(UMTS), 4G(LTE2300 and LTE2500), ISM, WLAN. It is quiet appropriate for the present ultra-thin smart phones

Flexible Hilbert-Curve Loop Antenna Having a Triple-Band and Omnidirectional Pattern for WLAN/WiMAX Applications

Directory of Open Access Journals (Sweden)

Dang-Oh Kim

2012-01-01

Full Text Available A triple-band flexible loop antenna is proposed for WLAN/WiMAX applications in this paper. The proposed antenna is formed by the third-order Hilbert-curve and bending type structure which provides flexible characteristics. Even though the radius of the curvature for bending antennas is changed, a triple-band feature still remains in the proposed antenna. Moreover, the antenna exhibits the characteristics of omnidirectional radiation pattern and circular polarization. To verify the receiving performance of antenna, a simulation on the antenna factor was conducted by an EM simulator. Based on these results, the suggested antenna makes a noteworthy performance over typical loop antennas.

Accurate Antenna Models in Ground Penetrating Radar Diffraction Tomography

DEFF Research Database (Denmark)

Meincke, Peter; Kim, Oleksiy S.

2002-01-01

are modeled by their plane-wave receiving and transmitting spectra. We find these spectra numerically for a resistively loaded dipole using the method of moments. Also, we illustrate, through a numerical example, the importance of taking into account the correct antenna pattern in GPR diffraction tomography.......Linear inversion schemes based on the concept of diffraction tomography have proven successful for ground penetrating radar (GPR) imaging. In many GPR surveys, the antennas of the GPR are located close to the air-soil interface and, therefore, it is important to incorporate the presence...... of this interface in the inversion scheme (see Hansen, T.B. and Meincke Johansen, P., IEEE Trans. Geoscience and Remote Sensing, vol.38, p.496-506, 2000). Hansen and Meincke Johansen modeled the antennas as ideal (Hertzian) electric dipoles. Since practical GPR antennas are not ideal, it is of interest...

Inkjet-Printed Wideband Antenna on Resin-Coated Paper Substrate for Curved Wireless Devices

KAUST Repository

Abutarboush, Hattan; Farooqui, Muhammad Fahad; Shamim, Atif

2015-01-01

A low-cost, inkjet-printed multiband monopole antenna for conformal wireless applications is presented for the first time. The antenna is implemented on a low cost resin coated paper substrate which can be used for conformal devices. The antenna developed here is composed of four branch lines on the radiator and three L-shaped slots on the ground plane that help to generate multiple bands without increasing the size of the antenna. The antenna has a compact size, making it suitable for handheld and wearable wireless devices. Details of the inkjet printing fabrication processes and related issues are presented. The antennas were characterized under flat and bent conditions and the results indicate that the antennas can cover most bands for mobile and wireless applications such as PCS, UMTS, GSM1900 and WLAN

Inkjet-Printed Wideband Antenna on Resin-Coated Paper Substrate for Curved Wireless Devices

KAUST Repository

Abutarboush, Hattan

2015-04-28

A low-cost, inkjet-printed multiband monopole antenna for conformal wireless applications is presented for the first time. The antenna is implemented on a low cost resin coated paper substrate which can be used for conformal devices. The antenna developed here is composed of four branch lines on the radiator and three L-shaped slots on the ground plane that help to generate multiple bands without increasing the size of the antenna. The antenna has a compact size, making it suitable for handheld and wearable wireless devices. Details of the inkjet printing fabrication processes and related issues are presented. The antennas were characterized under flat and bent conditions and the results indicate that the antennas can cover most bands for mobile and wireless applications such as PCS, UMTS, GSM1900 and WLAN

Low complexity transmit antenna selection with power balancing in OFDM systems

KAUST Repository

Park, Kihong

2010-10-01

In this paper, we consider multi-carrier systems with multiple transmit antennas under the power balancing constraint, which is defined as the constraint that the power on each antenna should be limited under a certain level due to the linearity of the power amplifier of the RF chain. Applying transmit antenna selection and fixed-power variable-rate transmission per subcarrier as a function of channel variations, we propose an implementation-friendly antenna selection method which offers a reduced complexity in comparison with the optimal antenna selection scheme. More specifically, in order to solve the subcarrier imbalance across the antennas, we operate a two-step reallocation procedure to minimize the loss of spectral efficiency. We also provide an analytic lower bound on the spectral efficiency for the proposed scheme. From selected numerical results, we show that our suboptimal scheme offers almost the same spectral efficiency as the optimal one. © 2010 IEEE.

EM Modeling of Far-Field Radiation Patterns for Antennas on the GMA-TT UAV

Science.gov (United States)

Mackenzie, Anne I.

2015-01-01

To optimize communication with the Generic Modular Aircraft T-Tail (GMA-TT) unmanned aerial vehicle (UAV), electromagnetic (EM) simulations have been performed to predict the performance of two antenna types on the aircraft. Simulated far-field radiation patterns tell the amount of power radiated by the antennas and the aircraft together, taking into account blockage by the aircraft as well as radiation by conducting and dielectric portions of the aircraft. With a knowledge of the polarization and distance of the two communicating antennas, e.g. one on the UAV and one on the ground, and the transmitted signal strength, a calculation may be performed to find the strength of the signal travelling from one antenna to the other and to check that the transmitted signal meets the receiver system requirements for the designated range. In order to do this, the antenna frequency and polarization must be known for each antenna, in addition to its design and location. The permittivity, permeability, and geometry of the UAV components must also be known. The full-wave method of moments solution produces the appropriate dBi radiation pattern in which the received signal strength is calculated relative to that of an isotropic radiator.

Envelope correlation in (N, N) MIMO antenna array from scattering parameters

DEFF Research Database (Denmark)

Thaysen, Jesper; Jakobsen, Kaj Bjarne

2006-01-01

the envelope correlation coefficient. This approach has the advantage that it does not require knowledge of the antenna radiation pattern. Numerical data that include conductor and permittivity loss are shown to validate the approach. Using the scattering parameters for calculating the envelope correlation......A simple closed-form equation to calculate the envelope correlation between any two receiver or transmitter antennas in a multi-input multi-output (MIMO) system of an arbitrary number of elements is derived. The equation uses the scattering parameters obtained at the antenna feed point to calculate...

Equipment: Antenna systems

Science.gov (United States)

Petrie, L. E.

1986-03-01

Some antenna fundamentals as well as definitions of the principal terms used in antenna engineering are described. Methods are presented for determining the desired antenna radiation patterns for HF communication circuit or service area. Sources for obtaining or computing radiation pattern information are outlined. Comparisons are presented between the measured and computed radiation patterns. The effect of the properties of the ground on the antenna gain and the pattern are illustrated for several types of antennas. Numerous examples are given of the radiation patterns for typical antennas used on short, intermediate and long distance circuits for both mobile and fixed service operations. The application of adaptive antenna arrays and active antennas in modern HF communication systems are briefly reviewed.

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.

Design and Simulation of a Compact UWB MIMO Antenna with Mutual Coupling Reduction

Directory of Open Access Journals (Sweden)

Narges Malekpoor

2016-01-01

Full Text Available In this paper, A compact multiple-input-multiple-output (MIMO antenna with a small size of 26×31mm2 is proposed for portable ultrawideband (UWB applications. The antenna consists of two square-monopole antenna with microstrip-fed by a 50- Ω printed on one side of the substrate. To enhance isolation and increase impedance bandwidth, two long ground stubs are added to the ground plane on the other side. Simulation is used to study the antenna performance in terms of reflection coefficients at the two input ports, coupling between the two input ports, radiation pattern, realized peak gain, efficiency and envelope correlation coefficient. Results show that the MIMO antenna has an impedance bandwidth ( for S22< -10 dB of larger than 3.1–10.6 GHz, low mutual coupling ( for S21< 3 dB of less than -16 dB, and a low envelope correlation coefficient of less than 0.003 across the frequency band, making it a good candidate for portable UWB applications.

Design of an electrically small circularly polarised turnstile antenna and its application to near-field wireless power transfer

DEFF Research Database (Denmark)

Yoon, Ick-Jae; Ling, Hao

2014-01-01

An electrically small circularly polarised antenna is designed and applied to near-field wireless power transfer as a means of alleviating orientation dependence. The antenna is miniaturised from a spl lambda//2-turnstile antenna by utilising the top loading and multiple folding techniques. A loc...... performance is verified in the far field. The power transfer efficiency is then examined in the near field via simulation and measurement. It is shown that the designed circularly polarised antenna is effective in mitigating orientation dependence down to a distance of 0.2λ.......An electrically small circularly polarised antenna is designed and applied to near-field wireless power transfer as a means of alleviating orientation dependence. The antenna is miniaturised from a spl lambda//2-turnstile antenna by utilising the top loading and multiple folding techniques. A local...... numerical search is used to determine the optimal antenna dimensions to achieve good axial ratio and impedance matching. The resulting design has a kr of 0.67 and shows good circular polarisation characteristic with a 3% axial ratio bandwidth. The designed antenna is fabricated and its circular polarisation...

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.

Interference Aware Inter-Cell Rank Coordination for 5G Wide Area Networks

DEFF Research Database (Denmark)

Mahmood, Nurul Huda; Pedersen, Klaus I.; Mogensen, Preben Elgaard

2017-01-01

Multiple receive and transmit antennas can be used to improve the spectral efficiency by transmitting over multiple independent streams. In addition, multiple receive antennas facilitate interference suppression through the use of interference rejection combining receivers. Rank adaptation algori...

Dynamic Modeling and Simulation of Marine Satellite Tracking Antenna Using Lagrange Method

DEFF Research Database (Denmark)

Wang, Yunlong; Soltani, Mohsen; Hussain, Dil muhammed Akbar

2016-01-01

Marine Satellite Tracking Antenna (MSTA) is a necessary device in ships for receiving satellite signals when they are sailing on the sea. This paper presents a simple methodology to obtain the dynamic equations of MSTA through Lagrange method, which is fundamental in design of modelbased controll......Marine Satellite Tracking Antenna (MSTA) is a necessary device in ships for receiving satellite signals when they are sailing on the sea. This paper presents a simple methodology to obtain the dynamic equations of MSTA through Lagrange method, which is fundamental in design of modelbased...

Aspects of High-Q Tunable Antennas and Their Deployment for 4G Mobile Communications

DEFF Research Database (Denmark)

Bahramzy, Pevand; Jagielski, Ole; Svendsen, Simon

2016-01-01

Tunable antennas are very promising for future generations of mobile communications, where broad frequency coverage will be required increasingly. This work describes the design of small high-Quality factor (Q) tunable antennas based on Micro-Electro-Mechanical Systems (MEMS), which are capable...... of operation in the frequency ranges 600 - 960 MHz and 1710 - 2690 MHz. Some aspects of high-Q tunable antennas are investigated through experimental measurements and the result are presented. Results show that more than -30 dB of isolation can be achieved between the Transmit (Tx) and Receive (Rx) antennas...

On-Chip Implantable Antennas for Wireless Power and Data Transfer in a Glaucoma-Monitoring SoC

KAUST Repository

Marnat, Loic

2013-04-17

For the first time separate transmit and receive onchip antennas have been designed in a eye environment for implantable intraocular pressure monitoring application. The miniaturized antennas fit on a 1.4 mm3 CMOS (0.18 μm) chip with the rest of the circuitry. A 5.2 GHz novel inductive fed and loaded receive monopole antenna is used for wireless powering the chip and is conjugately matched to the rectifier in the energy harvesting and storage unit. The 2.4 GHz transmit antenna is an octagonal loop which also acts as the inductor of the voltage control oscillator resonant tank. To emulate the eye environment in measurements, a custom test setup is developed which comprises plexiglass cavities filled with saline solution. A transition, employing a balun, is also designed which transforms the differential impedance of on-chip antennas immersed in saline solution to a 50 ! single-ended micrsotrip line. The antennas on a lossy Si substrate and eye environment provide sufficient gain to establish wireless communication with an external reader placed few cm away from the eye.

Antenna unit and radio base station therewith

Science.gov (United States)

Kuwahara, Mikio; Doi, Nobukazu; Suzuki, Toshiro; Ishida, Yuji; Inoue, Takashi; Niida, Sumaru

2007-04-10

Phase and amplitude deviations, which are generated, for example, by cables connecting an array antenna of a CDMA base station and the base station, are calibrated in the baseband. The base station comprises: an antenna apparatus 1; couplers 2; an RF unit 3 that converts a receive signal to a baseband signal, converts a transmit signal to a radio frequency, and performs power control; an A/D converter 4 for converting a receive signal to a digital signal; a receive beam form unit 6 that multiplies the receive signal by semi-fixed weight; a despreader 7 for this signal input; a time-space demodulator 8 for demodulating user data; a despreader 9 for probe signal; a space modulator 14 for user data; a spreader 13 for user signal; a channel combiner 12; a Tx calibrater 11 for controlling calibration of a signal; a D/A converter 10; a unit 16 for calculation of correlation matrix for generating a probe signal used for controlling an Rx calibration system and a TX calibration system; a spreader 17 for probe signal; a power control unit 18; a D/A converter 19; an RF unit 20 for probe signal; an A/D converter 21 for signal from the couplers 2; and a despreader 22.

Some remarks on antenna response in a reverberation chamber

Energy Technology Data Exchange (ETDEWEB)

WARNE,LARRY K.; LEE,K.S.H.

2000-03-15

The simple formula, {l_angle}P{sub r}{r_angle}=(E{sub o}{sup 2}/{eta})({lambda}{sup 2}/8{pi}), for the received power of an antenna with a matched load in an over-moded cavity actually holds for an antenna of any shape and size. This can be seen from the close connection between the correlation tensor of the cavity field at two different points and the imaginary part of the free-space dyadic Green's function.

Proceedings of the 1989 Antenna Applications Symposium. Volume 2

Science.gov (United States)

1990-03-01

Utilizing Closely 283 Spaced Printed Circuit Flared Slot Antenna Elements for Active Transmit and Receive Phased Array Demonstration," Mark J. Povinelli ...Notch Array, Mark J. Povinelli and John D’Angelo 19. "EHF Active Array, Joe Kobus 343 20. "Unique Joint Stars Phased-Array Antenna," H. Shnitkin 360 iv...Anten..as Propagat., vol. AP-33, pp. 1392-1400, Dec. 1985. [4] M. J. Povinelli and J. A. Johnson, "Design and performance of wideband, dual polarized

Minimum BER Receiver Filters with Block Memory for Uplink DS-CDMA Systems

Directory of Open Access Journals (Sweden)

Debbah Mérouane

2008-01-01

Full Text Available Abstract The problem of synchronous multiuser receiver design in the case of direct-sequence single-antenna code division multiple access (DS-CDMA uplink networks is studied over frequency selective fading channels. An exact expression for the bit error rate (BER is derived in the case of BPSK signaling. Moreover, an algorithm is proposed for finding the finite impulse response (FIR receiver filters with block memory such that the exact BER of the active users is minimized. Several properties of the minimum BER FIR filters with block memory are identified. The algorithm performance is found for scenarios with different channel qualities, spreading code lengths, receiver block memory size, near-far effects, and channel mismatch. For the BPSK constellation, the proposed FIR receiver structure with block memory has significant better BER with respect to and near-far resistance than the corresponding minimum mean square error (MMSE filters with block memory.

Spread Spectrum Receiver Electromagnetic Interference (EMI) Test Guide

Science.gov (United States)

Wheeler, M. L.

1998-01-01

The objective of this test guide is to document appropriate unit level test methods and techniques for the performance of EMI testing of Direct Sequence (DS) spread spectrum receivers. Consideration of EMI test methods tailored for spread spectrum receivers utilizing frequency spreading, techniques other than direct sequence (such as frequency hopping, frequency chirping, and various hybrid methods) is beyond the scope of this test guide development program and is not addressed as part of this document EMI test requirements for NASA programs are primarily developed based on the requirements contained in MIL-STD-46 1 D (or earlier revisions of MIL-STD-46 1). The corresponding test method guidelines for the MIL-STD-461 D tests are provided in MIL-STD-462D. These test methods are well documented with the exception of the receiver antenna port susceptibility tests (intermodulation, cross modulation, and rejection of undesired signals) which must be tailored to the specific type of receiver that is being tested. Thus, test methods addressed in this guide consist only of antenna port tests designed to evaluate receiver susceptibility characteristics. MIL-STD-462D should be referred for guidance pertaining to test methods for EMI tests other than the antenna port tests. The scope of this test guide includes: (1) a discussion of generic DS receiver performance characteristics; (2) a summary of S-band TDRSS receiver operation; (3) a discussion of DS receiver EMI susceptibility mechanisms and characteristics; (4) a summary of military standard test guidelines; (5) recommended test approach and methods; and (6) general conclusions and recommendations for future studies in the area of spread spectrum receiver testing.

Placement insensitive antenna for RFID, sensing, and/or communication systems

Science.gov (United States)

Bernhard, Jennifer T.; Ruyle, Jessica E.

2014-06-10

An antenna includes a ground plane having a slot. The slot may be miniaturized using a meandered slot structure or other appropriate reactive loading method as an end load to one or both ends of the slot. An edge treatment may be included on one or more edges of the ground plane or a closely spaced reflecting plane. The antenna is structured to transmit or receive a signal independently or in response to electromagnetic radiation.

Exploiting Phase Diversity for CDMA2000 1X Smart Antenna Base Stations

Science.gov (United States)

Kim, Seongdo; Hyeon, Seungheon; Choi, Seungwon

2004-12-01

A performance analysis of an access channel decoder is presented which exploits a diversity gain due to the independent magnitude of received signals energy at each of the antenna elements of a smart-antenna base-station transceiver subsystem (BTS) operating in CDMA2000 1X signal environment. The objective is to enhance the data retrieval at cellsite during the access period, for which the optimal weight vector of the smart antenna BTS is not available. It is shown in this paper that the access channel decoder proposed in this paper outperforms the conventional one, which is based on a single antenna channel in terms of detection probability of access probe, access channel failure probability, and Walsh-code demodulation performance.

Precision Antenna Measurement System (PAMS) Engineering Services

Science.gov (United States)

1978-04-01

8217) = receiving antenna gain for vertical polarization. The total direct signal power is Following Beck /narn and Spizzachino , the specular component...method may be valid for the problem. Very often, however, the physical optics 92 approach baaed on a solution of the wave equation will have to

Mantle cloaking for co-site radio-frequency antennas

Energy Technology Data Exchange (ETDEWEB)

Monti, Alessio, E-mail: alessio.monti@uniroma3.it; Barbuto, Mirko [“Niccolò Cusano” University, Via Don Carlo Gnocchi 3, Rome 00166 (Italy); Soric, Jason; Alù, Andrea [Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Ramaccia, Davide; Vellucci, Stefano; Toscano, Alessandro; Bilotti, Filiberto [Department of Engineering, “Roma Tre” University, Via Vito Volterra 62, Rome 00146 (Italy); Trotta, Fabrizio [Antenna Department, ELETTRONICA S.p.A., Via Tiburtina Valeria Km 13700, Rome 00131 (Italy)

2016-03-14

We show that properly designed mantle cloaks, consisting of patterned metallic sheets placed around cylindrical monopoles, allow tightly packing the same antennas together in a highly dense telecommunication platform. Our experimental demonstration is applied to the relevant example of two cylindrical monopole radiators operating for 3G and 4G mobile communications. The two antennas are placed in close proximity, separated by 1/10 of the shorter operational wavelength, and, after cloaking, are shown to remarkably operate as if isolated in free-space. This result paves the way to unprecedented co-siting strategies for multiple antennas handling different services and installed in overcrowded platforms, such as communication towers, satellite payloads, aircrafts, or ship trees. More broadly, this work presents a significant application of cloaking technology to improve the efficiency of modern communication systems.

Mantle cloaking for co-site radio-frequency antennas

International Nuclear Information System (INIS)

Monti, Alessio; Barbuto, Mirko; Soric, Jason; Alù, Andrea; Ramaccia, Davide; Vellucci, Stefano; Toscano, Alessandro; Bilotti, Filiberto; Trotta, Fabrizio

2016-01-01

We show that properly designed mantle cloaks, consisting of patterned metallic sheets placed around cylindrical monopoles, allow tightly packing the same antennas together in a highly dense telecommunication platform. Our experimental demonstration is applied to the relevant example of two cylindrical monopole radiators operating for 3G and 4G mobile communications. The two antennas are placed in close proximity, separated by 1/10 of the shorter operational wavelength, and, after cloaking, are shown to remarkably operate as if isolated in free-space. This result paves the way to unprecedented co-siting strategies for multiple antennas handling different services and installed in overcrowded platforms, such as communication towers, satellite payloads, aircrafts, or ship trees. More broadly, this work presents a significant application of cloaking technology to improve the efficiency of modern communication systems.

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

Near-Field Antenna Measurements Using Photonic Sensor of Mach-Zehnder Interferometer

Directory of Open Access Journals (Sweden)

Masanobu Hirose

2012-01-01

Full Text Available We have been developing a photonic sensor system to measure the electric near-field distribution at a distance shorter than one wavelength from the aperture of an antenna. The photonic sensor is a type of Mach-Zehnder interferometer and consists of an array antenna of 2.4 mm height and 2 mm width on a LiNbO3 substrate (0.5 mm thickness, 8 mm length, and 3 mm width supported by a glass pipe. The photonic sensor can be considered to be a receiving infinitesimal dipole antenna that is a tiny metallic part printed on a small dielectric plate at microwave frequency. Those physical and electrical features make the photonic sensor attractive when used as a probe for near-field antenna measurements. We have demonstrated that the system can be applied to planar, spherical, and cylindrical near-field antenna measurements without any probe compensation approximately below 10 GHz. We show the theories and the measurements using the photonic sensor in the three near-field antenna measurement methods.

Development of film antenna for diversity reception; Diversity taio film antenna no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Shigeta, K; Taniguchi, T; Kubota, K [Mazda Motor Corp., Hiroshima (Japan)

1997-10-01

Based on the principle of capacitance-loaded window antennas, a new film antenna construction pasting an antenna element on a defogger element printed on a rear window was found. The film antennas show high reception performance, and can be used as television diversity antennas or a VICS-FM multiplex antenna. This paper describes the antenna design concept, the antenna construction and the application to a recreational vehicle which styling is 1.3-Box wagon for the electric accessory. 2 refs., 11 figs.

'Chaos' in superregenerative receivers

Energy Technology Data Exchange (ETDEWEB)

Commercon, Jean-Claude [INSA, Department d' Informatiques, Ba-hat t B. Pascal, 20 Avenue Albert Einsten, 69621 Villeurbaune (France)]. E-mail: jean-claude.commercon@insa-lyon.fr; Badard, Robert [INSA, Department d' Informatiques, Bat B. Pascal, 20 Avenue Albert Einsten, 69621 Villeurbaune (France)]. E-mail: robert.badard@insa-lyon.fr

2005-02-01

The superregenerative principle has been known since the early 1920s. The circuit is extremely simple and extremely sensitive. Today, superheterodyne receivers generally supplant superregenerative receivers in most applications because there are several undesirable characteristics: poor selectivity, reradiation, etc. Superregenerative receivers undergo a revival in recent papers for wireless systems, where low cost and very low power consumption are relevant: house/building meters (such as water, energy, gas counter), personal computer environment (keyboard, mouse), etc. Another drawback is the noise level which is higher than that of a well-designed superheterodyne receiver; without an antenna input signal, the output of the receiver hears in an earphone as a waterfall noise; this sound principally is the inherent input noise amplified and detected by the circuit; however, when the input noise is negligible with respect of an antenna input signal, we are faced to an other source of 'noise' self-generated by the superregenerative working. The main objective of this paper concerns this self-generated noise coming from an exponential growing followed by a re-injection process for which the final state is a function of the phase of the input signal.

Polymer (PDMS-Fe3O4) magneto-dielectric substrate for a MIMO antenna array

Science.gov (United States)

Alqadami, Abdulrahman Shueai Mohsen; Jamlos, Mohd Faizal; Soh, Ping Jack; Kamarudin, Muhammad Ramlee

2016-01-01

This paper presents the design of a 2 × 4 multiple-input multiple-output (MIMO) antenna array fabricated on a nanocomposite magneto-dielectric polymer substrate. The 10-nm iron oxide (Fe3O4) nanoparticles and polydimethylsiloxane (PDMS) composite is used as substrate to enhance the performance of a MIMO antenna array. The measured results showed up to 40.8 % enhancement in terms of bandwidth, 9.95 dB gain, and 57 % of radiation efficiency. Furthermore, it is found that the proposed magneto-dielectric (PDMS-Fe3O4) composite substrate provides excellent MIMO parameters such as correlation coefficient, diversity gain, and mutual coupling. The prototype of the proposed antenna is transparent, flexible, lightweight, and resistant against dust and corrosion. Measured results indicate that the proposed antenna is suitable for WLAN and ultra-wideband biomedical applications within frequency range of 5.33-7.70 GHz.

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.

Adaptive multi-node multiple input and multiple output (MIMO) transmission for mobile wireless multimedia sensor networks.

Science.gov (United States)

Cho, Sunghyun; Choi, Ji-Woong; You, Cheolwoo

2013-10-02

Mobile wireless multimedia sensor networks (WMSNs), which consist of mobile sink or sensor nodes and use rich sensing information, require much faster and more reliable wireless links than static wireless sensor networks (WSNs). This paper proposes an adaptive multi-node (MN) multiple input and multiple output (MIMO) transmission to improve the transmission reliability and capacity of mobile sink nodes when they experience spatial correlation. Unlike conventional single-node (SN) MIMO transmission, the proposed scheme considers the use of transmission antennas from more than two sensor nodes. To find an optimal antenna set and a MIMO transmission scheme, a MN MIMO channel model is introduced first, followed by derivation of closed-form ergodic capacity expressions with different MIMO transmission schemes, such as space-time transmit diversity coding and spatial multiplexing. The capacity varies according to the antenna correlation and the path gain from multiple sensor nodes. Based on these statistical results, we propose an adaptive MIMO mode and antenna set switching algorithm that maximizes the ergodic capacity of mobile sink nodes. The ergodic capacity of the proposed scheme is compared with conventional SN MIMO schemes, where the gain increases as the antenna correlation and path gain ratio increase.

Performance Enhancement of Land Vehicle Positioning Using Multiple GPS Receivers in an Urban Area

Directory of Open Access Journals (Sweden)

Jong-Hwa Song

2016-10-01

Full Text Available The Global Positioning System (GPS is the most widely used navigation system in land vehicle applications. In urban areas, the GPS suffers from insufficient signal strength, multipath propagation and non-line-of-sight (NLOS errors, so it thus becomes difficult to obtain accurate and reliable position information. In this paper, an integration algorithm for multiple receivers is proposed to enhance the positioning performance of GPS for land vehicles in urban areas. The pseudoranges of multiple receivers are integrated based on a tightly coupled approach, and erroneous measurements are detected by testing the closeness of the pseudoranges. In order to fairly compare the pseudoranges, GPS errors and terms arising due to the differences between the positions of the receivers need to be compensated. The double-difference technique is used to eliminate GPS errors in the pseudoranges, and the geometrical distance is corrected by projecting the baseline vector between pairs of receivers. In order to test and analyze the proposed algorithm, an experiment involving live data was performed. The positioning performance of the algorithm was compared with that of the receiver autonomous integrity monitoring (RAIM-based integration algorithm for multiple receivers. The test results showed that the proposed algorithm yields more accurate position information in urban areas.

The Effect of Mutual Coupling on a High Altitude Platform Diversity System Using Compact Antenna Arrays

Directory of Open Access Journals (Sweden)

Tommy Hult

2010-01-01

Full Text Available We analyze the destructive effects of mutual coupling and spatial correlation between the separate antenna elements on a combined diversity system consisting of multiple HAPs (High-Altitude Platforms employing various compact MIMO (Multiple-Input Multiple-Output antenna array configurations, in order to enhance the mutual information in HAP communication links. In addition, we assess the influence of the separation angle between HAPs on system performance, and determine the optimal separation angles that maximize the total mutual information of the system for various compact MIMO antennas. Simulation results show that although the mutual information is degraded by mutual coupling and spatial correlation, the proposed HAP diversity system still provides better performance compared to a nondiversity system for all tested scenarios.

Transmit antenna selection based on shadowing side information

KAUST Repository

Yilmaz, Ferkan

2011-05-01

In this paper, we propose a new transmit antenna selection scheme based on shadowing side information. In the proposed scheme, single transmit antenna which has the highest shadowing coefficient is selected. By the proposed technique, usage of the feedback channel and channel estimation complexity at the receiver can be reduced. We consider independent but not identically distributed Generalized-K composite fading model, which is a general composite fading & shadowing channel model for wireless environments. Exact closed-form outage probability, moment generating function and symbol error probability expressions are derived. In addition, theoretical performance results are validated by Monte Carlo simulations. © 2011 IEEE.

Transmit antenna selection based on shadowing side information

KAUST Repository

Yilmaz, Ferkan; Yilmaz, Ahmet Oǧuz; Alouini, Mohamed-Slim; Kucur, Oǧuz

2011-01-01

In this paper, we propose a new transmit antenna selection scheme based on shadowing side information. In the proposed scheme, single transmit antenna which has the highest shadowing coefficient is selected. By the proposed technique, usage of the feedback channel and channel estimation complexity at the receiver can be reduced. We consider independent but not identically distributed Generalized-K composite fading model, which is a general composite fading & shadowing channel model for wireless environments. Exact closed-form outage probability, moment generating function and symbol error probability expressions are derived. In addition, theoretical performance results are validated by Monte Carlo simulations. © 2011 IEEE.

Non-Foster Circuits for High Performance Antennas: Advantages and Practical Limitations

Science.gov (United States)

Jacob, Minu Mariam

The demand for miniaturized, broadband communication systems has created a need for electrically small, broadband antennas. However, all passive electrically small antennas have a fundamental gain-bandwidth limitation related to their electrical size, as first described by Wheeler and Chu. This limitation can be overcome using active non-Foster circuits (negative inductors and/or negative capacitors), which can deliver a broadband input match with active matching techniques, or can help reduce phase dispersion using negative delay effects. This thesis will illustrate the advantages of non-Foster circuits in obtaining broadband small antennas, in addition to examining their practical limitations due to noise in receive applications, and nonlinearity in transmit applications.

Exploiting Phase Diversity for CDMA2000 1X Smart Antenna Base Stations

Directory of Open Access Journals (Sweden)

Hyeon Seungheon

2004-01-01

Full Text Available A performance analysis of an access channel decoder is presented which exploits a diversity gain due to the independent magnitude of received signals energy at each of the antenna elements of a smart-antenna base-station transceiver subsystem (BTS operating in CDMA2000 1X signal environment. The objective is to enhance the data retrieval at cellsite during the access period, for which the optimal weight vector of the smart antenna BTS is not available. It is shown in this paper that the access channel decoder proposed in this paper outperforms the conventional one, which is based on a single antenna channel in terms of detection probability of access probe, access channel failure probability, and Walsh-code demodulation performance.

Babinet-Inverted Optical Yagi-Uda Antenna for Unidirectional Radiation to Free Space

Science.gov (United States)

Kim, Jineun; Roh, Young-Geun; Cheon, Sangmo; Choe, Jong-Ho; Lee, Jongcheon; Lee, Jaesoong; Jeong, Heejeong; Kim, Un Jeong; Park, Yeonsang; Song, In Yong; Park, Q.-Han; Hwang, Sung Woo; Kim, Kinam; Lee, Chang-Won

2014-06-01

Plasmonic nanoantennas are key elements in nanophotonics capable of directing radiation or enhancing the transition rate of a quantum emitter. Slot-type magnetic-dipole nanoantennas, which are complementary structures of typical electric-dipole-type antennas, have received little attention, leaving their antenna properties largely unexplored. Here we present a novel magnetic-dipole-fed multi-slot optical Yagi-Uda antenna. By engineering the relative phase of the interacting surface plasmon polaritons between the slot elements, we demonstrate that the optical antenna exhibits highly unidirectional radiation to free space. The unique features of the slot-based magnetic nanoantenna provide a new possibility of achieving integrated features such as energy transfer from one waveguide to another by working as a future optical via.

B Sundar Rajan, IISc, Bangalore

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 ...

Minimum BER Receiver Filters with Block Memory for Uplink DS-CDMA Systems

Directory of Open Access Journals (Sweden)

Mérouane Debbah

2008-05-01

Full Text Available The problem of synchronous multiuser receiver design in the case of direct-sequence single-antenna code division multiple access (DS-CDMA uplink networks is studied over frequency selective fading channels. An exact expression for the bit error rate (BER is derived in the case of BPSK signaling. Moreover, an algorithm is proposed for finding the finite impulse response (FIR receiver filters with block memory such that the exact BER of the active users is minimized. Several properties of the minimum BER FIR filters with block memory are identified. The algorithm performance is found for scenarios with different channel qualities, spreading code lengths, receiver block memory size, near-far effects, and channel mismatch. For the BPSK constellation, the proposed FIR receiver structure with block memory has significant better BER with respect to Eb/N0 and near-far resistance than the corresponding minimum mean square error (MMSE filters with block memory.

Long range ultra-high frequency (UHF) radio frequency identification (RFID) antenna design

Science.gov (United States)

Reynolds, Nathan D.

There is an ever-increasing demand for radio frequency identification (RFID) tags that are passive, long range, and mountable on multiple surfaces. Currently, RFID technology is utilized in numerous applications such as supply chain management, access control, and public transportation. With the combination of sensory systems in recent years, the applications of RFID technology have been extended beyond tracking and identifying. This extension includes applications such as environmental monitoring and healthcare applications. The available sensory systems usually operate in the medium or high frequency bands and have a low read range. However, the range limitations of these systems are being overcome by the development of RFID sensors focused on utilizing tags in the ultra-high frequency (UHF) band. Generally, RFID tags have to be mounted to the object that is being identified. Often the objects requiring identification are metallic. The inherent properties of metallic objects have substantial effects on nearby electromagnetic radiation; therefore, the operation of the tag antenna is affected when mounted on a metallic surface. This outlines one of the most challenging problems for RFID systems today: the optimization of tag antenna performance in a complex environment. In this research, a novel UHF RFID tag antenna, which has a low profile, long range, and is mountable on metallic surfaces, is designed analytically and simulated using a 3-D electromagnetic simulator, ANSYS HFSS. A microstrip patch antenna is selected as the antenna structure, as patch antennas are low profile and suitable for mounting on metallic surfaces. Matching and theoretical models of the microstrip patch antenna are investigated. Once matching and theory of a microstrip patch antenna is thoroughly understood, a unique design technique using electromagnetic band gap (EBG) structures is explored. This research shows that the utilization of an EBG structure in the patch antenna design yields

Antenna theory: Analysis and design

Science.gov (United States)

Balanis, C. A.

The book's main objective is to introduce the fundamental principles of antenna theory and to apply them to the analysis, design, and measurements of antennas. In a description of antennas, the radiation mechanism is discussed along with the current distribution on a thin wire. Fundamental parameters of antennas are examined, taking into account the radiation pattern, radiation power density, radiation intensity, directivity, numerical techniques, gain, antenna efficiency, half-power beamwidth, beam efficiency, bandwidth, polarization, input impedance, and antenna temperature. Attention is given to radiation integrals and auxiliary potential functions, linear wire antennas, loop antennas, linear and circular arrays, self- and mutual impedances of linear elements and arrays, broadband dipoles and matching techniques, traveling wave and broadband antennas, frequency independent antennas and antenna miniaturization, the geometrical theory of diffraction, horns, reflectors and lens antennas, antenna synthesis and continuous sources, and antenna measurements.

Energy Efficiency Analysis of Antenna Selection Techniques in Massive MIMO-OFDM System with Hardware Impairments

Directory of Open Access Journals (Sweden)

Anuj Singal

2018-01-01

Full Text Available In massive multiple-input multiple-output (M-MIMO systems, a large number of antennas increase system complexity as well as the cost of hardware. In this paper, we propose an M-MIMO-OFDM model using per-subcarrier antenna selection and bulk antenna selection schemes to mitigate these problems. Also, we derive a new uplink and downlink energy efficiency (EE equation for the M-MIMO-OFDM system by taking into consideration the antenna selection schemes, power scaling factor (g=0.25,  0.5, and a range of hardware impairments {κBS, κUEϵ (0, 0.052, 0.12}. In addition, we investigate a trend of EE by varying various parameters like number of base station antennas (BSAs, SNR, level of hardware impairments, total circuit power consumption, power optimization, antenna selection schemes, and power scaling factor in the proposed M-MIMO-OFDM model. The simulation results thus obtained show that the EE increases with increase in the value of SNR. Also, it increases abruptly up to 100 number of BSA. However, the increase in the EE is not significant in the range of 125 to 400 number of BSA. Further, the bulk antenna selection technique has comparatively more EE than the per-subcarrier antenna selection. Moreover, EE gaps between antenna selection schemes decrease with increase in the value of hardware impairments and power scaling factor. However, as the hardware degradation effect increases, the EE of the bulk antenna selection scheme suffers more degradation as compared to the Per-subcarrier antenna selection scheme. It has also been observed that EE performance is inversely proportional to the total circuit power consumption (λ+γ and it increases with the power optimization.

Substrate-Integrated Waveguide PCB Leaky-Wave Antenna Design Providing Multiple Steerable Beams in the V-Band

Directory of Open Access Journals (Sweden)

Matthias Steeg

2017-12-01

Full Text Available A periodic leaky-wave antenna (LWA design based on low loss substrate-integrated waveguide (SIW technology with inset half-wave microstrip antennas is presented. The developed LWA operates in the V-band between 50 and 70 GHz and has been fabricated using standard printed circuit board (PCB technology. The presented LWA is highly functional and very compact supporting 1D beam steering and multibeam operation with only a single radio frequency (RF feeding port. Within the operational 50–70 GHz bandwidth, the LWA scans through broadside, providing over 40° H-plane beam steering. When operated within the 57–66 GHz band, the maximum steering angle is 18.2°. The maximum gain of the fabricated LWAs is 15.4 dBi with only a small gain variation of +/−1.5 dB across the operational bandwidth. The beam steering and multibeam capability of the fabricated LWA is further utilized to support mobile users in a 60 GHz hot-spot. For a single user, a maximum wireless on-off keying (OOK data rate of 2.5 Gbit/s is demonstrated. Multibeam operation is achieved using the LWA in combination with multiple dense wavelength division multiplexing (WDM channels and remote optical heterodyning. Experimentally, multibeam operation supporting three users within a 57–66 GHz hot-spot with a total wireless cell capacity of 3 Gbit/s is achieved.

Identification and characterization of multiple emissive species in aggregated minor antenna complexes

Czech Academy of Sciences Publication Activity Database

Wahadoszamen, M.; Belgio, Erica; Rahman, M.A.; Ara, A.M.; Ruban, A.V.; van Grondelle, R.

2016-01-01

Roč. 1857, č. 12 (2016), s. 1917-1924 ISSN 0005-2728 Institutional support: RVO:61388971 Keywords : Light harvesting * Minor antenna complexes * Photoprotective energy dissipation Subject RIV: EE - Microbiology, Virology Impact factor: 4.932, year: 2016

Band-notched spiral antenna

Science.gov (United States)

Jeon, Jae; Chang, John

2018-03-13

A band-notched spiral antenna having one or more spiral arms extending from a radially inner end to a radially outer end for transmitting or receiving electromagnetic radiation over a frequency range, and one or more resonance structures positioned adjacent one or more segments of the spiral arm associated with a notch frequency band or bands of the frequency range so as to resonate and suppress the transmission or reception of electromagnetic radiation over said notch frequency band or bands.

Antenna conditioning with insulating antenna tiles in Phaedrus-T

International Nuclear Information System (INIS)

Intrator, T.; Probert, P.; Doczy, M.; Diebold, D.; Brouchous, D.

1994-01-01

In the course of our Alfven wave heating and current drive experiments several different two and four strap antennas have been installed in Phaedrus-T. The motivation focusing the redesign of the antenna into a four strap design was to enable traveling wave phasing, and to reduce the k parallel ∼0 component of the wavenumber spectrum, and consequent edge power deposition. The latest modifications to the 4 strap antenna have dramatically improved its behavior, and enabled us to suppress its RF power induced impurity generation. The remaining gas reflux fueling is significant and is not local to the antenna

Design and Simulation of Horn Antenna Using CST Software for GPR System

Science.gov (United States)

Joret, Ariffuddin; Sulong, M. S.; Abdullah, M. F. L.; Madun, Aziman; Haimi Dahlan, Samsul

2018-04-01

Detection of underground object can be made using a GPR system. This system is classified as a non-destructive technique (NDT) where the ground areas need not to be excavated. The technique used by the GPR system is by measuring the reflection of electromagnetic wave signal produced and detected by antenna which is known as the transmitter and the receiver antenna. In this study, a GPR system was studied by means of simulation using a Horn antenna as a transceiver antenna. The electromagnetic wave signal in this simulation is produced by current signal of an antenna which having a shape of modulation of Gaussian pulse which is having spectrum from 8 GHz until 12 GHz. CST and MATLAB Software are used in this GPR system simulation. A model of a Horn antenna has been designed using the CST software before the GPR’s system simulation modeled by adding a model of background in front of the Horn antenna. The simulation results show that the output signal of the Horn antenna can be used in detecting embedded object which are made from material of wood and iron. In addition, the simulation result has successfully developed a 3D model image of the GPR system using output signal of the Horn antenna. The embedded iron object in the GPR system simulation can be seen clearly by using this 3D image.

Balancing Uplink and Downlink under Asymmetric Traffic Environments Using Distributed Receive Antennas

Science.gov (United States)

Sohn, Illsoo; Lee, Byong Ok; Lee, Kwang Bok

Recently, multimedia services are increasing with the widespread use of various wireless applications such as web browsers, real-time video, and interactive games, which results in traffic asymmetry between the uplink and downlink. Hence, time division duplex (TDD) systems which provide advantages in efficient bandwidth utilization under asymmetric traffic environments have become one of the most important issues in future mobile cellular systems. It is known that two types of intercell interference, referred to as crossed-slot interference, additionally arise in TDD systems; the performances of the uplink and downlink transmissions are degraded by BS-to-BS crossed-slot interference and MS-to-MS crossed-slot interference, respectively. The resulting performance unbalance between the uplink and downlink makes network deployment severely inefficient. Previous works have proposed intelligent time slot allocation algorithms to mitigate the crossed-slot interference problem. However, they require centralized control, which causes large signaling overhead in the network. In this paper, we propose to change the shape of the cellular structure itself. The conventional cellular structure is easily transformed into the proposed cellular structure with distributed receive antennas (DRAs). We set up statistical Markov chain traffic model and analyze the bit error performances of the conventional cellular structure and proposed cellular structure under asymmetric traffic environments. Numerical results show that the uplink and downlink performances of the proposed cellular structure become balanced with the proper number of DRAs and thus the proposed cellular structure is notably cost-effective in network deployment compared to the conventional cellular structure. As a result, extending the conventional cellular structure into the proposed cellular structure with DRAs is a remarkably cost-effective solution to support asymmetric traffic environments in future mobile cellular

Single-Axis Three-Beam Amplitude Monopulse Antenna-Signal Processing Issues

Energy Technology Data Exchange (ETDEWEB)

Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bickel, Douglas L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-05-01

Typically, when three or more antenna beams along a single axis are required, the answer has been multiple antenna phase-centers, essentially a phase-monopulse system. Such systems and their design parameters are well-reported in the literature. Less appreciated is that three or more antenna beams can also be generated in an amplitude-monopulse fashion. Consequently, design guidelines and performance analysis of such antennas is somewhat under-reported in the literature. We provide discussion herein of three beams arrayed in a single axis with an amplitude-monopulse configuration. Acknowledgements The preparation of this report is the result of an unfunded research and development activity. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administ ration under contract DE-AC04-94AL85000.

Antenna Design Considerations for the Advanced Extravehicular Mobility Unit

Science.gov (United States)

Bakula, Casey J.; Theofylaktos, Onoufrios

2015-01-01

NASA is designing an Advanced Extravehicular Mobility Unit (AEMU)to support future manned missions beyond low-Earth orbit (LEO). A key component of the AEMU is the communications assembly that allows for the wireless transfer of voice, video, and suit telemetry. The Extravehicular Mobility Unit (EMU) currently used on the International Space Station (ISS) contains a radio system with a single omni-directional resonant cavity antenna operating slightly above 400 MHz capable of transmitting and receiving data at a rate of about 125 kbps. Recent wireless communications architectures are calling for the inclusion of commercial wireless standards such as 802.11 that operate in higher frequency bands at much higher data rates. The current AEMU radio design supports a 400 MHz band for low-rate mission-critical data and a high-rate band based on commercial wireless local area network (WLAN) technology to support video, communication with non-extravehicular activity (EVA) assets such as wireless sensors and robotic assistants, and a redundant path for mission-critical EVA data. This paper recommends the replacement of the existing EMU antenna with a new antenna that maintains the performance characteristics of the current antenna but with lower weight and volume footprints. NASA has funded several firms to develop such an antenna over the past few years, and the most promising designs are variations on the basic patch antenna. This antenna technology at UHF is considered by the authors to be mature and ready for infusion into NASA AEMU technology development programs.

Generation of OAM Radio Waves Using Circular Vivaldi Antenna Array

Directory of Open Access Journals (Sweden)

Changjiang Deng

2013-01-01

Full Text Available This paper gives a feasible and simple solution of generating OAM-carrying radio beams. Eight Vivaldi antenna elements connect sequentially and fold into a hollow cylinder. The circular Vivaldi antenna array is fed with unit amplitude but with a successive phase difference from element to element. By changing the phase difference at the steps of 0, ±45°, ±90°, ±135°, and 180°, the OAM radio beam can be generated with mode numbers 0, ±1, ±2, ±3, and 4. Simulations show that the OAM states of ±2 and ±3 are the same as the traditional states, while the OAM states of 0, ±1, and 4 differ at the boresight. This phenomenon can be explained by the radiation pattern difference between Vivaldi antenna and tripole antenna. A solution of distinguishing OAM states is also proposed. The mode number of OAM can be distinguished with only 2 receivers.

On-Chip Implantable Antennas for Wireless Power and Data Transfer in a Glaucoma-Monitoring SoC

KAUST Repository

Marnat, Loic; Arsalan, Muhammad; Ouda, Mahmoud H.; Salama, Khaled N.; Shamim, Atif

2013-01-01

For the first time separate transmit and receive onchip antennas have been designed in a eye environment for implantable intraocular pressure monitoring application. The miniaturized antennas fit on a 1.4 mm3 CMOS (0.18 μm) chip with the rest

A Space-Time Signal Decomposition Algorithm for Downlink MIMO DS-CDMA Receivers

Science.gov (United States)

Wang, Yung-Yi; Fang, Wen-Hsien; Chen, Jiunn-Tsair

We propose a dimension reduction algorithm for the receiver of the downlink of direct-sequence code-division multiple access (DS-CDMA) systems in which both the transmitters and the receivers employ antenna arrays of multiple elements. To estimate the high order channel parameters, we develop a layered architecture using dimension-reduced parameter estimation algorithms to estimate the frequency-selective multipath channels. In the proposed architecture, to exploit the space-time geometric characteristics of multipath channels, spatial beamformers and constrained (or unconstrained) temporal filters are adopted for clustered-multipath grouping and path isolation. In conjunction with the multiple access interference (MAI) suppression techniques, the proposed architecture jointly estimates the direction of arrivals, propagation delays, and fading amplitudes of the downlink fading multipaths. With the outputs of the proposed architecture, the signals of interest can then be naturally detected by using path-wise maximum ratio combining. Compared to the traditional techniques, such as the Joint-Angle-and-Delay-Estimation (JADE) algorithm for DOA-delay joint estimation and the space-time minimum mean square error (ST-MMSE) algorithm for signal detection, computer simulations show that the proposed algorithm substantially mitigate the computational complexity at the expense of only slight performance degradation.

On Small Antenna Measurements in a Realistic MIMO Scenario

DEFF Research Database (Denmark)

Yanakiev, Boyan; Nielsen, Jesper Ødum; Pedersen, Gert Frølund

2010-01-01

. The problem using coaxial cable is explained and a solution suitable for long distance channel sounding is presented. A large scale measurement campaign is then described. Special attention is paid to bring the measurement setup as close as possible to a realistic LTE network of the future, with attention......This paper deals with the challenges related to evaluating the performance of multiple, small terminal antennas within a natural MIMO environment. The focus is on the antenna measurement accuracy. First a method is presented for measuring small phone mock-ups, with the use of optical fibers...

Investigation of interference in multiple-input multiple-output wireless transmission at W band for an optical wireless integration system.

Science.gov (United States)

Li, Xinying; Yu, Jianjun; Dong, Ze; Zhang, Junwen; Chi, Nan; Yu, Jianguo

2013-03-01

We experimentally investigate the interference in multiple-input multiple-output (MIMO) wireless transmission by adjusting the relative locations of horn antennas (HAs) in a 100 GHz optical wireless integration system, which can deliver a 50 Gb/s polarization-division-multiplexing quadrature-phase-shift-keying signal over 80 km single-mode fiber-28 and a 2×2 MIMO wireless link. For the parallel 2×2 MIMO wireless link, each receiver HA can only get wireless power from the corresponding transmitter HA, while for the crossover ones, the receiver HA can get wireless power from two transmitter HAs. At the wireless receiver, polarization demultiplexing is realized by the constant modulus algorithm (CMA) in the digital-signal-processing part. Compared to the parallel case, wireless interference causes about 2 dB optical signal-to-noise ratio penalty at a bit-error ratio (BER) of 3.8×10(-3) for the crossover cases if similar CMA taps are employed. The increase in CMA tap length can reduce wireless interference and improve BER performance. Furthermore, more CMA taps should be adopted to overcome the severe wireless interference when two pairs of transmitter and receiver HAs have different wireless distances.

Design of a ring resonator-based optical beam forming network for phased array receive antennas

NARCIS (Netherlands)

van 't Klooster, J.W.J.R.; Roeloffzen, C.G.H.; Meijerink, Arjan; Zhuang, L.; Marpaung, D.A.I.; van Etten, Wim; Heideman, Rene; Leinse, Arne; Schippers, H.; Verpoorte, J.; Wintels, M.

2008-01-01

A novel squint-free ring resonator-based optical beam forming network (OBFN) for phased array antennas (PAA) is proposed. It is intended to provide broadband connectivity to airborne platforms via geostationary satellites. In this paper, we present the design of the OBFN and its control system. Our

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.

Antenna Controller Replacement Software

Science.gov (United States)

Chao, Roger Y.; Morgan, Scott C.; Strain, Martha M.; Rockwell, Stephen T.; Shimizu, Kenneth J.; Tehrani, Barzia J.; Kwok, Jaclyn H.; Tuazon-Wong, Michelle; Valtier, Henry; Nalbandi, Reza;

Perturbation approach to design of circularly polarised microstrip antennas

Science.gov (United States)

Lo, Y. T.; Richards, W. F.

1981-05-01

One of the most interesting applications of microstrip antennas is its use for transmitting or receiving circularly polarized (CP) waves. A description is given of a simple but accurate method to determine the critical dimensions needed to produce circular polarization for nearly square and nearly circular microstrip antennas. Shen (1981) in connection with the determination of the proper dimensions of an elliptical patch CP microstrip antenna first expressed the modal field in terms of Mathieu functions. To avoid the complicated numerical computation of the Mathieu functions, he approximated these functions in terms of Bessel functions. It is pointed out that the computation of Mathieu functions, or their approximate expressions can be avoided altogether if a perturbation method is applied to find the resonant frequencies of the two orthogonal modes. The implementation of this approach is demonstrated.

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.

Experimentally achieving borehole antenna radar directivity in the time domain in the presence of strong mutual coupling

CSIR Research Space (South Africa)

Vogt, D

2008-06-01

Full Text Available published borehole radar antennas have achieved directivity by post processing data received in the frequency domain, or by constructing an aperture antenna, where borehole dimensions allowed this. In this paper, a time-domain technique is investigated...

Wireless thin film transistor based on micro magnetic induction coupling antenna.

Science.gov (United States)

Jun, Byoung Ok; Lee, Gwang Jun; Kang, Jong Gu; Kim, Seunguk; Choi, Ji-Woong; Cha, Seung Nam; Sohn, Jung Inn; Jang, Jae Eun

2015-12-22

A wireless thin film transistor (TFT) structure in which a source/drain or a gate is connected directly to a micro antenna to receive or transmit signals or power can be an important building block, acting as an electrical switch, a rectifier or an amplifier, for various electronics as well as microelectronics, since it allows simple connection with other devices, unlike conventional wire connections. An amorphous indium gallium zinc oxide (α-IGZO) TFT with magnetic antenna structure was fabricated and studied for this purpose. To enhance the induction coupling efficiency while maintaining the same small antenna size, a magnetic core structure consisting of Ni and nanowires was formed under the antenna. With the micro-antenna connected to a source/drain or a gate of the TFT, working electrical signals were well controlled. The results demonstrated the device as an alternative solution to existing wire connections which cause a number of problems in various fields such as flexible/wearable devices, body implanted devices, micro/nano robots, and sensors for the 'internet of things' (IoT).

Wireless thin film transistor based on micro magnetic induction coupling antenna

Science.gov (United States)

Jun, Byoung Ok; Lee, Gwang Jun; Kang, Jong Gu; Kim, Seunguk; Choi, Ji-Woong; Cha, Seung Nam; Sohn, Jung Inn; Jang, Jae Eun

2015-12-01

A wireless thin film transistor (TFT) structure in which a source/drain or a gate is connected directly to a micro antenna to receive or transmit signals or power can be an important building block, acting as an electrical switch, a rectifier or an amplifier, for various electronics as well as microelectronics, since it allows simple connection with other devices, unlike conventional wire connections. An amorphous indium gallium zinc oxide (α-IGZO) TFT with magnetic antenna structure was fabricated and studied for this purpose. To enhance the induction coupling efficiency while maintaining the same small antenna size, a magnetic core structure consisting of Ni and nanowires was formed under the antenna. With the micro-antenna connected to a source/drain or a gate of the TFT, working electrical signals were well controlled. The results demonstrated the device as an alternative solution to existing wire connections which cause a number of problems in various fields such as flexible/wearable devices, body implanted devices, micro/nano robots, and sensors for the ‘internet of things’ (IoT).

Fully inkjet printed wide band cantor fractal antenna for RF energy harvesting application

KAUST Repository

Bakytbekov, Azamat

2017-06-07

Energy harvesting from ambient RF signals is feasible, particularly from the GSM bands such as 900MHz, 1800MHz and the 3G band at 2.1GHz. This requires a wideband receive antenna which can cover all these bands with decent gain performance and an omnidirectional radiation pattern. In this work, a novel Cantor fractal antenna has been designed which fulfills the above mentioned performance requirements. Antenna has been realized through a combination of 3D inkjet printing of plastic substrate and 2D inkjet printing of metallic nanoparticles based ink. The stable impedance and radiation performance of the antenna over a bandwidth of 0.8GHz to 2.2GHz (93 %) shows the feasibility of its employment in wide band energy harvesting applications.

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

Multi-Destination Cognitive Radio Relay Network with SWIPT and Multiple Primary Receivers

KAUST Repository

Al-Habob, Ahmed A.; Salhab, Anas M.; Zummo, Salam A.; Alouini, Mohamed-Slim

2017-01-01

In this paper, we study the performance of simultaneous wireless information and power transfer (SWIPT) technique in a multi-destination dual-hop underlay cognitive relay network with multiple primary receivers. Information transmission from

Rectangular Ring Antenna Excited by Circular Disc Monopole for WiMAX System

Directory of Open Access Journals (Sweden)

Souphanna Vongsack

2014-01-01

Full Text Available This research presents a rectangular ring antenna excited by a circular disc monopole (CDM mounted in front of a square reflector. The proposed antenna is designed to cover a frequency range of 2.300–5.825 GHz and thereby is suitable for WiMAX applications. Multiple parametric studies were carried out using the CST Microwave Studio simulation program. A prototype antenna was fabricated and experimented. The measurements were taken and compared with the simulation results, which indicates good agreement between both results. The prototype antenna produces an impedance bandwidth (|S11| < −10 dB that covers the WiMAX frequency range and a constant unidirectional radiation pattern (θ=0° and ∅=90°. The minimum and maximum gains are 3.7 and 8.7 dBi, respectively. The proposed antenna is of compact size and has good unidirectional radiation performance. Thus, it is very suitable for a multitude of WiMAX applications.

Calculation of the self-consistent current distribution and coupling of an RF antenna array

International Nuclear Information System (INIS)

Ballico, M.; Puri, S.

1993-10-01

A self-consistent calculation of the antenna current distribution and fields in an axisymmetric cylindrical geometry for the ICRH antenna-plasma coupling problem is presented. Several features distinguish this calculation from other codes presently available. 1. Variational form: The formulation of the self consistent antenna current problem in a variational form allows good convergence and stability of the algorithm. 2. Multiple straps: Allows modelling of (a) the current distribution across the width of the strap (by dividing it up into sub straps) (b) side limiters and septum (c) antenna cross-coupling. 3. Analytic calculation of the antenna field and calculation of the antenna self-consistent current distribution, (given the surface impedance matrix) gives rapid calculation. 4. Framed for parallel computation on several different parallel architectures (as well as serial) gives a large speed improvement to the user. Results are presented for both Alfven wave heating and current drive antenna arrays, showing the optimal coupling to be achieved for toroidal mode numbers 8< n<10 for typical ASDEX upgrade plasmas. Simulations of the ASDEX upgrade antenna show the importance of the current distribution across the antenna and of image currents flowing in the side limiters, and an analysis of a proposed asymmetric ITER antenna is presented. (orig.)

Adaptation of the Electra Radio to Support Multiple Receive Channels

Science.gov (United States)

Satorius, Edgar H.; Shah, Biren N.; Bruvold, Kristoffer N.; Bell, David J.

2011-01-01

Proposed future Mars missions plan communication between multiple assets (rovers). This paper presents the results of a study carried out to assess the potential adaptation of the Electra radio to a multi-channel transceiver. The basic concept is a Frequency Division multiplexing (FDM) communications scheme wherein different receiver architectures are examined. Options considered include: (1) multiple IF slices, A/D and FPGAs each programmed with an Electra baseband modem; (2) common IF but multiple A/Ds and FPGAs and (3) common IF, single A/D and single or multiple FPGAs programmed to accommodate the FDM signals. These options represent the usual tradeoff between analog and digital complexity. Given the space application, a common IF is preferable; however, multiple users present dynamic range challenges (e.g., near-far constraints) that would favor multiple IF slices (Option 1). Vice versa, with a common IF and multiple A/Ds (Option 2), individual AGC control of the A/Ds would be an important consideration. Option 3 would require a common AGC control strategy and would entail multiple digital down conversion paths within the FPGA. In this paper, both FDM parameters as well as the different Electra design options will be examined. In particular, signal channel spacing as a function of user data rates and transmit powers will be evaluated. In addition, tradeoffs between the different Electra design options will be presented with the ultimate goal of defining an augmented Electra radio architecture for potential future missions.

Solving “Antenna Array Thinning Problem” Using Genetic Algorithm

Directory of Open Access Journals (Sweden)

Rajashree Jain

2012-01-01

Full Text Available Thinning involves reducing total number of active elements in an antenna array without causing major degradation in system performance. Dynamic thinning is the process of achieving this under real-time conditions. It is required to find a strategic subset of antenna elements for thinning so as to have its optimum performance. From a mathematical perspective this is a nonlinear, multidimensional problem with multiple objectives and many constraints. Solution for such problem cannot be obtained by classical analytical techniques. It will be required to employ some type of search algorithm which can lead to a practical solution in an optimal. The present paper discusses an approach of using genetic algorithm for array thinning. After discussing the basic concept involving antenna array, array thinning, dynamic thinning, and application methodology, simulation results of applying the technique to linear and planar arrays are presented.

All-optical delay technique for supporting multiple antennas in a hybrid optical - wireless transmission system

DEFF Research Database (Denmark)

Prince, Kamau; Chiuchiarelli, A; Presi, M

2008-01-01

We introduce a novel continuously-variable optical delay technique to support beam-forming wireless communications systems using antenna arrays. We demonstrate delay with 64-QAM modulated signals at a rate of 15 Msymbol/sec with 2.5 GHz carrier frequency.......We introduce a novel continuously-variable optical delay technique to support beam-forming wireless communications systems using antenna arrays. We demonstrate delay with 64-QAM modulated signals at a rate of 15 Msymbol/sec with 2.5 GHz carrier frequency....

Large space antenna communications systems: Integrated Langley Research Center/Jet Propulsion Laboratory development activities. 2: Langley Research Center activities

Science.gov (United States)

Cambell, T. G.; Bailey, M. C.; Cockrell, C. R.; Beck, F. B.

1983-01-01

The electromagnetic analysis activities at the Langley Research Center are resulting in efficient and accurate analytical methods for predicting both far- and near-field radiation characteristics of large offset multiple-beam multiple-aperture mesh reflector antennas. The utilization of aperture integration augmented with Geometrical Theory of Diffraction in analyzing the large reflector antenna system is emphasized.

The use of civilian-type GPS receivers by the military and their vulnerability to jamming

Directory of Open Access Journals (Sweden)

Ludwig Combrinck

2012-05-01

Full Text Available We considered the impact of external influences on a GPS receiver and how these influences affect the capabilities of civilian-type GPS receivers. A standard commercial radio frequency signal generator and passive GPS antenna were used to test the sensitivity of GPS to intentional jamming; the possible effects of the terrain on the propagation of the jamming signal were also tested. It was found that the high sensitivity of GPS receivers and the low strength level of GPS satellite signals combine to make GPS receivers very vulnerable to intentional jamming or unintentional radio frequency interference. Terrain undulation was used to shield GPS antennas from the direct line-of-sight of the jamming antenna and this indicated that terrain characteristics can be used to mitigate the effects of jamming. These results illuminate the vulnerability of civilian-type GPS receivers to the possibility and the ease of disablement and establish the foundation for future work.

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.

Patch Antenna based on a Photovoltaic Cell with a Dual resonance Frequency

Directory of Open Access Journals (Sweden)

C. Baccouch

2016-11-01

Full Text Available The present work was to use photovoltaic solar cells in patch antenna structures. The radiating patch element of a patch antenna was replaced by a solar cell. Direct Current (DC generation remained the original feature of the solar cell, but additionally   it was now able to receive and transmit electromagnetic waves. Here, we used a new patch antenna structure based on a photovoltaic solar cell. It was then used to collect photo-generated current as well as Radio Frequency (RF transmission. A mathematical model which would serve the minimization of power losses of the cell and therefore the improvement in the conversion efficiency was studied. A simulation allowed analysing the performance of the antenna, with a silicon material, and testing its parameters such as the reflection coefficient (S11, gain, directivity and radiated power. The performance analysis of the solar cell patch antenna was conducted using Advanced Design System (ADS software. Simulation results for this antenna showed a dual resonance frequency of 5.77 GHz and of 6.18 GHz with an effective return loss of -38.22dB and a gain of 1.59dBi.

Direction Finding Using Multiple Sum and Difference Patterns in 4D Antenna Arrays

Directory of Open Access Journals (Sweden)

Quanjiang Zhu

2014-01-01

Full Text Available Traditional monopulse systems used for direction finding usually face the contradiction between high angle precision and wide angle-searching field, and a compromise has to be made. In this paper, the time modulation technique in four-dimensional (4D antenna array is introduced into the conventional phase-comparison monopulse to form a novel direction-finding system, in which both high angle resolution and wide field-of-view are realized. The full 4D array is divided into two subarrays and the differential evolution (DE algorithm is used to optimize the time sequence of each subarray to generate multibeams at the center frequency and low sidebands. Then the multibeams of the two subarrays are phase-compared with each other and multiple pairs of sum-difference beams are formed at different sidebands and point to different spatial angles. The proposed direction-finding system covers a large field-of-view of up to ±60° and simultaneously maintains the advantages of monopulse systems, such as high angle precision and low computation complexity. Theoretical analysis and experimental results validate the effectiveness of the proposed system.

A multiband dual-standard MIMO antenna system based on monopoles (4G) and connected slots (5G) for future smart phones

KAUST Repository

Ikram, M.; Sharawi, M. S.; Shamim, Atif; Sebak, A.

2018-01-01

In this work, a 4G/5G multiple-input multiple-output (MIMO) antenna system is presented for smart phone applications. The 4G antenna operates from 1900 to 3212 MHz and 3517 to 3712 MHz with 1312 (69%) and 195 (5.5%) MHz measured bandwidths

Ultrawideband Vivaldi Antenna for DVB-T, WLAN, and WiMAX Applications

Directory of Open Access Journals (Sweden)

Dalia M. Elsheakh

2014-01-01

Full Text Available Compact Vivaldi patch antenna with a parasitic meander line is presented in this paper. A PIN diode switch is used to connect and disconnect ultrahigh frequency band (UHF with ultrawide bandwidth (UWB. The operating frequencies can be switched among different services, depending on the switching states (ON/OFF to add the lower band when required. This antenna is suitable for portable DVB-T which extended from 450 MHz to 850 MHz receiver applications and the WLAN (Wireless Local Area Network IEEE 802.11b,g (5.1–5.8 GHz frequency bands and WiMAX band (3.3–3.8 GHz. The measured reflection coefficient of the proposed antenna is compared with the simulated one; good agreement is observed. Also, simulated radiation pattern of the antenna is presented. All simulations are carried out using the EM commercial simulator, high frequency structure simulator (HFSS ver.13.

Fabrication and impact performance of three-dimensionally integrated microstrip antennas with microstrip and coaxial feeding

International Nuclear Information System (INIS)

Yao, Lan; Wang, Xin; Xu, Fujun; Zhao, Da; Jiang, Muwen; Qiu, Yiping

2009-01-01

A conformal load-bearing antenna structure (CLAS) combines the antenna into a composite structure such that it can carry the designed load while functioning as an antenna. In this paper, two types of new 3D integrated microstrip antennas (3DIMAs) with different feeding methods are designed to work at the radar L-band. Different from the conventional CLAS, the radiating patch and the ground plane of the 3DIMA are both composed of woven conductive wires and are bonded into the 3D composite physically by Z-yarns, greatly improving the damage tolerance of the antenna. The return loss of the coaxial-fed antenna is −13.15 dB with a resonant frequency of 1.872 GHz, while that of the microstrip-fed antenna is −31.50 dB with a resonant frequency of 1.33 GHz. Both of the 3DIMAs have similar radiation patterns to that of the traditionally designed microstrip antenna. In addition, an experimental investigation of the impact response of the coaxial-fed 3DIMA was carried out and the results showed the radiation pattern had almost no change even when the antenna received an impact energy of 15 J, exhibiting superior impact resistance to that of a conventional microstrip antenna

Customizable Digital Receivers for Radar

Science.gov (United States)

Moller, Delwyn; Heavey, Brandon; Sadowy, Gregory

2008-01-01

Compact, highly customizable digital receivers are being developed for the system described in 'Radar Interferometer for Topographic Mapping of Glaciers and Ice Sheets' (NPO-43962), NASA Tech Briefs, Vol. 31, No. 7 (August 2007), page 72. The receivers are required to operate in unison, sampling radar returns received by the antenna elements in a digital beam-forming (DBF) mode. The design of these receivers could also be adapted to commercial radar systems. At the time of reporting the information for this article, there were no commercially available digital receivers capable of satisfying all of the operational requirements and compact enough to be mounted directly on the antenna elements. A provided figure depicts the overall system of which the digital receivers are parts. Each digital receiver includes an analog-to-digital converter (ADC), a demultiplexer (DMUX), and a field-programmable gate array (FPGA). The ADC effects 10-bit band-pass sampling of input signals having frequencies up to 3.5 GHz. The input samples are demultiplexed at a user-selectable rate of 1:2 or 1:4, then buffered in part of the FPGA that functions as a first-in/first-out (FIFO) memory. Another part of the FPGA serves as a controller for the ADC, DMUX, and FIFO memory and as an interface between (1) the rest of the receiver and (2) a front-panel data port (FPDP) bus, which is an industry-standard parallel data bus that has a high data-rate capability and multichannel configuration suitable for DBF. Still other parts of the FPGA in each receiver perform signal-processing functions. The digital receivers can be configured to operate in a stand-alone mode, or in a multichannel mode as needed for DBF. The customizability of the receiver makes it applicable to a broad range of system architectures. The capability for operation of receivers in either a stand-alone or a DBF mode enables the use of the receivers in an unprecedentedly wide variety of radar systems.

An Optimal Beamforming Algorithm for Phased-Array Antennas Used in Multi-Beam Spaceborne Radiometers

DEFF Research Database (Denmark)

Iupikov, O. A.; Ivashina, M. V.; Pontoppidan, K.

2015-01-01

Strict requirements for future spaceborne ocean missions using multi-beam radiometers call for new antenna technologies, such as digital beamforming phased arrays. In this paper, we present an optimal beamforming algorithm for phased-array antenna systems designed to operate as focal plane arrays...... to a FPA feeding a torus reflector antenna (designed under the contract with the European Space Agency) and tested for multiple beams. The results demonstrate an improved performance in terms of the optimized beam characteristics, yielding much higher spatial and radiometric resolution as well as much...

Linear antenna of an arbitrary orientation and position in cylindric screen

International Nuclear Information System (INIS)

Prijmenko, S.D.; Papkovich, V.G.; Khizhnyak, N.A.

1991-01-01

An equation of the linear antenna in cylindric screen is formulated. Using the averaging method a solution of this equation for the antenna of arbitrary orientation which does not contact the screen walls or contacts them in one or two ends is received. The obtained asymptotic expression for stream permits to describe in a single manner the case of resonance and non-resonance scattering. These results may be applied in design of UHF and accelerating installations using cylindric screens charged with linear vibrators. 9 refs. (author)

Comparison of Low-Complexity Diversity Schemes for Dual-Hop AF Relaying Systems

KAUST Repository

Gaaloul, Fakhreddine

2012-02-13

This paper investigates the performance of two low-complexity combining schemes, which are based on one- or two-phase observation, to mitigate multipath fading in dual-hop amplify-and-forward relaying systems. For the one-phase-based combining, a single-antenna station is assumed to relay information from a multiple-antenna transmitter to a multiple-antenna receiver, and the activation of the receive antennas is adaptively performed based on the second-hop statistics, regardless of the first-hop conditions. On the other hand, the two-phase-based combining suggests using multiple single-antenna stations between the multiple-antenna transmitter and the single-antenna receiver, where the suitable set of active relays is identified according to the precombining end-to-end fading conditions. To facilitate comparisons between the two schemes, formulations for the statistics of the combined signal-to-noise ratio and some performance measures are presented. Numerical and simulation results are shown to clarify the tradeoff between the achieved diversity-array gain, the processing complexity, and the power consumption.

Wide-band antenna design for use in minimal-scan, microwave tomographic imaging

Science.gov (United States)

Klaser, Jacob

Microwave tomography is widely used in biomedical imaging and nondestructive evaluation of dielectric materials. A novel microwave tomography system that uses an electrically-conformable mirror to steer the incident energy for producing multi-view projection data is being developed in the Non-Destructive Evaluation Laboratory (NDEL). Such a system will have a significant advantage over existing tomography systems in terms of simplicity of design and operation, particularly when there is limited-access of the structure that is being imaged. The major components of a mirror-based tomography system are the source mirror assembly, and a receiver array for capturing the multi-view projection data. This thesis addresses the design and development of the receiver array. This imaging array features balanced, anti-podal Vivaldi antennas, which offer large bandwidth, high gain and a compact size. From the simulations, as well as the experimental results for the antenna, the return loss (S 11) is below -10dB for the range from 2.2GHz to 8.2GHz, and the gain is measured to be near 6dB. The data gathered from the receiver array is then run through MATLAB code for tomographic reconstruction using the Filtered Back-Propagation algorithm from limited-view projections. Initial results of reconstruction from the measured data shows the feasibility of the approach, but a significant challenge remains in interpolating the data for a limited number of receiving antenna elements and removing noise from the reconstructed image.

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....... The reconstruction of the extreme near field on the basis of near- or far-field measurements is thus an essential step in antenna diagnostics....

Ultrabroadband Phased-Array Receivers Based on Optical Techniques

Science.gov (United States)

2016-02-26

bandwidths, and with it receiver noise floors , are unavoidable. Figure 1. SNR of a thermally limited receiver based on Friis equation showing the...techniques for RF and photonic integration based on liquid crystal polymer substrates were pursued that would aid in the realization of potential imaging...These models assumed that sufficient LNA gain was used on the antenna to set the noise floor of the imaging receiver, which necessitated physical

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.

Cellular Reflectarray Antenna

Science.gov (United States)

Romanofsky, Robert R.

2010-01-01

The cellular reflectarray antenna is intended to replace conventional parabolic reflectors that must be physically aligned with a particular satellite in geostationary orbit. These arrays are designed for specified geographical locations, defined by latitude and longitude, each called a "cell." A particular cell occupies nominally 1,500 square miles (3,885 sq. km), but this varies according to latitude and longitude. The cellular reflectarray antenna designed for a particular cell is simply positioned to align with magnetic North, and the antenna surface is level (parallel to the ground). A given cellular reflectarray antenna will not operate in any other cell.

Numerical Simulation of Antennas with Improved Integral Equation Method

International Nuclear Information System (INIS)

Ma Ji; Fang Guang-You; Lu Wei

2015-01-01

Simulating antennas around a conducting object is a challenge task in computational electromagnetism, which is concerned with the behaviour of electromagnetic fields. To analyze this model efficiently, an improved integral equation-fast Fourier transform (IE-FFT) algorithm is presented in this paper. The proposed scheme employs two Cartesian grids with different size and location to enclose the antenna and the other object, respectively. On the one hand, IE-FFT technique is used to store matrix in a sparse form and accelerate the matrix-vector multiplication for each sub-domain independently. On the other hand, the mutual interaction between sub-domains is taken as the additional exciting voltage in each matrix equation. By updating integral equations several times, the whole electromagnetic system can achieve a stable status. Finally, the validity of the presented method is verified through the analysis of typical antennas in the presence of a conducting object. (paper)

Low-Gain Circularly Polarized Antenna with Torus-Shaped Pattern

Science.gov (United States)

Amaro, Luis R.; Kruid, Ronald C.; Vacchione, Joseph D.; Prata, Aluizio

2012-01-01

The Juno mission to Jupiter requires an antenna with a torus-shaped antenna pattern with approximately 6 dBic gain and circular polarization over the Deep Space Network (DSN) 7-GHz transmit frequency and the 8-GHz receive frequency. Given the large distances that accumulate en-route to Jupiter and the limited power afforded by the solar-powered vehicle, this toroidal low-gain antenna requires as much gain as possible while maintaining a beam width that could facilitate a +/-10deg edge of coverage. The natural antenna that produces a toroidal antenna pattern is the dipole, but the limited approx. = 2.2 dB peak gain would be insufficient. Here a shaped variation of the standard bicone antenna is proposed that could achieve the required gains and bandwidths while maintaining a size that was not excessive. The final geometry that was settled on consisted of a corrugated, shaped bicone, which is fed by a WR112 waveguide-to-coaxial- waveguide transition. This toroidal low-gain antenna (TLGA) geometry produced the requisite gain, moderate sidelobes, and the torus-shaped antenna pattern while maintaining a very good match over the entire required frequency range. Its "horn" geometry is also low-loss and capable of handling higher powers with large margins against multipactor breakdown. The final requirement for the antenna was to link with the DSN with circular polarization. A four-layer meander-line array polarizer was implemented; an approach that was fairly well suited to the TLGA geometry. The principal development of this work was to adapt the standard linear bicone such that its aperture could be increased in order to increase the available gain of the antenna. As one increases the aperture of a standard bicone, the phase variation across the aperture begins to increase, so the larger the aperture becomes, the greater the phase variation. In order to maximize the gain from any aperture antenna, the phase should be kept as uniform as possible. Thus, as the standard

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.

A satellite-tracking millimeter-wave reflector antenna system for mobile satellite-tracking

Science.gov (United States)

Densmore, Arthur C.; Jamnejad, Vahraz; Woo, Kenneth E.

1995-03-01

A miniature dual-band two-way mobile satellite tracking antenna system mounted on a movable ground vehicle includes a miniature parabolic reflector dish having an elliptical aperture with major and minor elliptical axes aligned horizontally and vertically, respectively, to maximize azimuthal directionality and minimize elevational directionality to an extent corresponding to expected pitch excursions of the movable ground vehicle. A feed-horn has a back end and an open front end facing the reflector dish and has vertical side walls opening out from the back end to the front end at a lesser horn angle and horizontal top and bottom walls opening out from the back end to the front end at a greater horn angle. An RF circuit couples two different signal bands between the feed-horn and the user. An antenna attitude controller maintains an antenna azimuth direction relative to the satellite by rotating it in azimuth in response to sensed yaw motions of the movable ground vehicle so as to compensate for the yaw motions to within a pointing error angle. The controller sinusoidally dithers the antenna through a small azimuth dither angle greater than the pointing error angle while sensing a signal from the satellite received at the reflector dish, and deduces the pointing angle error from dither-induced fluctuations in the received signal.

Modeling, Simulation, and Measurement of Balanced Antipodal Vivaldi (BAV) Antennas for Fully Polarimetric Forward-Looking Ground-Penetrating Radar (FLGPR) Receive Channels

Science.gov (United States)

2017-08-01

Current Vivaldi Elements and Replacement Antennas Considered The majority of the design process was conducted through modeling and simulation ...ARL-TR-8111 ● AUG 2017 US Army Research Laboratory Modeling, Simulation , and Measurement of Balanced Antipodal Vivaldi (BAV...ARL-TR-8111 ● AUG 2017 US Army Research Laboratory Modeling, Simulation , and Measurement of Balanced Antipodal Vivaldi (BAV) Antennas for

Preliminary Antenna Concept for the ngVLA

Science.gov (United States)

Di Francesco, James; Selina, Robert; Grammer, Wes; McKinnon, Mark M.

2017-01-01

The preliminary concept for a Next Generation Very Large Array (ngVLA) calls for an interferometric array having an effective collecting area and spatial resolution that are both 10 times better than that of the current VLA and operating over a frequency range of 1.2-116 GHz. Given the large number of antennas needed to meet the collecting area goal, the ngVLA antenna concept must strike a balance between competing science requirements and the programmatic targets for the array’s life cycle cost.Antenna diameters currently under consideration for the ngVLA are in the range of 12-25 m, with a nominal 18-m diameter aperture used for the conceptual design. Currently, the optimization for operations and construction cost suggests that a smaller number of larger apertures is preferable.The surface accuracy goal for the antennas is 185 µm rms (λ/16 @ 100 GHz) for the primary and subreflector combined under optimal environmental conditions. The subreflector will be optimized for performance above 10 GHz, with some degradation in aperture efficiency accepted at lower frequencies.For high dynamic range imaging, particularly at the low end of the ngVLA’s frequency range, the optimum optical configuration is likely an offset geometry. An unblocked aperture will minimize scattering, spillover, and sidelobe pickup. Both performance and maintenance requirements favor a receiver feedarm on the low side of the reflector.High pointing accuracy will also be necessary to provide the imaging dynamic range required of the system. With an unblocked aperture, variations in the antenna gain pattern are expected to be dominated by pointing errors. Preliminary requirements are for an absolute pointing accuracy of 40” RMS, with referenced pointing of 3” RMS (FWHM/10 at 10 GHz and 120 GHz, respectively, for an 18-m diameter dish).The antenna mount is expected to be a typical altitude-azimuth design. Both pedestal bearing and rail-based azimuth drives are under consideration. If fast

Determination of antenna factors using a three-antenna method at open-field test site

Science.gov (United States)

Masuzawa, Hiroshi; Tejima, Teruo; Harima, Katsushige; Morikawa, Takao

1992-09-01

Recently NIST has used the three-antenna method for calibration of the antenna factor of an antenna used for EMI measurements. This method does not require the specially designed standard antennas which are necessary in the standard field method or the standard antenna method, and can be used at an open-field test site. This paper theoretically and experimentally examines the measurement errors of this method and evaluates the precision of the antenna-factor calibration. It is found that the main source of the error is the non-ideal propagation characteristics of the test site, which should therefore be measured before the calibration. The precision of the antenna-factor calibration at the test site used in these experiments, is estimated to be 0.5 dB.

An efficient hexagonal switched beam antenna structure based on Fabry-Perot cavity leaky-wave antenna

Science.gov (United States)

Aymen El Cafsi, Mohamed; Nedil, Mourad; Osman, Lotfi; Gharsallah, Ali

2015-11-01

A novel design of switched beam antenna (SBA) system based on Fabry-Perot cavity leaky-wave antenna (FPC LWA) is designed and fabricated for base station operating in the unlicensed ISM central frequency band at 5.8 GHz of the wireless local area network (WLAN) standard. The proposed SBA is designed with hexagonal shape of FPC LWA Arrays in order to get 360° of coverage. The single element of FPC LWA array is composed of a patch antenna and covered by a Partially Reflective Surface (PRS), which is composed of a Metal Strip Grating and printed on a high permittivity Superstrate. First, the Transmission Line Model of FPC LWA is introduced to analyse and calculate the far-field components in E- and H planes by using the Transverse Equivalent Network. This approach is then compared with other full wave's commercial software such as Ansoft HFSS and CST Microwave Studio. Second, a parametric study is performed to evaluate the effect of the angle formed by the two successive FPC LWA on the radiation efficiency of the activate sector. To examine the performance of the proposed SBA, experimental prototype was fabricated and measured. As a result, multiple orthogonal beams (six beams) of 10 dBi of gain with low Side Lobes Level and 360° of coverage are produced. This SBA structure is suitable for WLAN communication systems.

Performance Analysis of Compact FD-MIMO Antenna Arrays in a Correlated Environment

KAUST Repository

Nadeem, Qurrat-Ul-Ain

2017-03-06

Full dimension multiple-input-multiple-output (FDMIMO) is one of the key technologies proposed in the 3rd Generation Partnership Project (3GPP) for the fifth generation (5G) communication systems. The reason can be attributed to its ability to yield significant performance gains through the deployment of active antenna elements at the base station in the vertical as well as the conventional horizontal directions, enabling several elevation beamforming strategies. The resulting improvement in spectral efficiency largely depends on the orthogonality of the sub-channels constituting the FD-MIMO system. Accommodating a large number of antenna elements with sufficient spacing poses several constraints for practical implementation, making it imperative to consider compact antenna arrangements that minimize the overall channel correlation. Two such configurations considered in this work are the uniform linear array (ULA) and the uniform circular array (UCA) of antenna ports, where each port is mapped to a group of physical antenna elements arranged in the vertical direction. The generalized analytical expression for the spatial correlation function (SCF) for the UCA is derived, exploiting results on spherical harmonics and Legendre polynomials. The mutual coupling between antenna dipoles is accounted for and the resulting SCF is also presented. The second part of this work compares the spatial correlation and mutual information (MI) performance of the ULA and UCA configurations in the 3GPP 3D urban-macro and urban-micro cell scenarios, utilizing results from Random Matrix Theory (RMT) on the deterministic equivalent of the MI for the Kronecker channel model. Simulation results study the performance patterns of the two arrays as a function of several channel and array parameters and identify applications and environments suitable for the deployment of each array.

Directional borehole antenna - Theory

International Nuclear Information System (INIS)

Falk, L.

1992-02-01

A directional antenna has been developed for the borehole radar constructed during phase 2 of the Stripa project. The new antenna can determine the azimuth of a strong reflector with an accuracy of about 3 degrees as confirmed during experiments in Stripa, although the ratio of borehole diameter to wavelength is small, about 0.03. The antenna synthesizes the effect of a loop antenna rotating in the borehole from four signals measured in turn by a stationary antenna. These signals are also used to calculate an electric dipole signal and a check sum which is used to examine the function of the system. The theory of directional antennas is reviewed and used to design an antenna consisting of four parallel wires. The radiation pattern of this antenna is calculated using transmission line theory with due regard to polarization, which is of fundamental importance for the analysis of directional data. In particular the multipole expansion of the field is calculated to describe the antenna radiation pattern. Various sources of error, e.g. the effect of the borehole, are discussed and the methods of calibrating the antenna are reviewed. The ambiguity inherent in a loop antenna can be removed by taking the phase of the signal into account. Typical reflectors in rock, e.g. fracture zones an tunnels, may be modelled as simple geometrical structures. The corresponding analysis is described and exemplified on measurements from Stripa. Radar data is nowadays usually analyzed directly on the computer screen using the program RADINTER developed within the Stripa project. An algorithm for automatic estimation of the parameters of a reflector have been tested with some success. The relation between measured radar data and external coordinates as determined by rotational indicators is finally expressed in terms of Euler angles. (au)

Bandwidth provisioning in infrastructure-based wireless networks employing directional antennas

Energy Technology Data Exchange (ETDEWEB)

Hasiviswanthan, Shiva [Los Alamos National Laboratory; Zhao, Bo [PENN STATE UNIV.; Vasudevan, Sudarshan [UNIV OF MASS AMHERST; Yrgaonkar, Bhuvan [PENN STATE UNIV.

2009-01-01

Motivated by the widespread proliferation of wireless networks employing directional antennas, we study the problem of provisioning bandwidth in such networks. Given a set of subscribers and one or more access points possessing directional antennas, we formalize the problem of orienting these antennas in two fundamental settings: (1) subscriber-centric, where the objective is to fairly allocate bandwidth among the subscribers and (2) provider-centric, where the objective is to maximize the revenue generated by satisfying the bandwidth requirements of subscribers. For both the problems, we first design algorithms for a network with only one access point working under the assumption that the number of antennas does not exceed the number of noninterfering channels. Using the well-regarded lexicographic max-min fair allocation as the objective for a subscriber-centric network, we present an optimum dynamic programming algorithm. For a provider-centric network, the allocation problem turns out to be NP-hard. We present a greedy heuristic based algorithm that guarantees almost half of the optimum revenue. We later enhance both these algorithms to operate in more general networks with multiple access points and no restrictions on the relative numbers of antennas and channels. A simulation-based evaluation using OPNET demonstrates the efficacy of our approaches and provides us further in insights into these problems.

Optical antenna for a visible light communications receiver

Science.gov (United States)

Valencia-Estrada, Juan Camilo; García-Márquez, Jorge; Topsu, Suat; Chassagne, Luc

2018-01-01

Visible Light Communications (VLC) receivers adapted to be used in high transmission rates will eventually use either, high aperture lenses or non-linear optical elements capable of converting light arriving to the receiver into an electric signal. The high aperture lens case, reveals a challenge from an optical designers point-of-view. As a matter of fact, the lens must collect a wide aperture intensity flux using a limited aperture as its use is intended to portable devices. This last also limits both, lens thickness and its focal length. Here, we show a first design to be adapted to a VLC receiver that take these constraints into account. This paper describes a method to design catadioptric and monolithic lenses to be used as an optical collector of light entering from a near point light source as a spherical fan L with a wide acceptance angle α° and high efficiency. These lenses can be mass produced and therefore one can find many practical applications in VLC equipped devices. We show a first design for a near light source without magnification, and second one with a detector's magnification in a meridional section. We utilize rigorous geometric optics, vector analysis and ordinary differential equations.

Mutual Coupling Reduction of E-Shaped MIMO Antenna with Matrix of C-Shaped Resonators

Directory of Open Access Journals (Sweden)

Raghad Ghalib Saadallah Alsultan

2018-01-01

Full Text Available E-shaped multiple-input-multiple-output (MIMO microstrip antenna systems operating in WLAN and WiMAX bands (between 5 and 7.5 GHz are proposed with enhanced isolation features. The systems are comprised of two antennas that are placed parallel and orthogonal to each other, respectively. According to the simulation results, the operating frequency of the MIMO antenna system is 6.3 GHz, and mutual coupling is below −18 dB in a parallel arrangement, whereas they are 6.4 GHz and −25 dB, respectively, in the orthogonal arrangement. The 2 × 3 matrix of C-shaped resonator (CSR is proposed and placed between the antenna elements over the substrate, to reduce the mutual coupling and enhance the isolation between the antennas. More than 30 dB isolation between the array elements is achieved at the resonant frequency for both of the configurations. The essential parameters of the MIMO array such as mutual coupling, surface current distribution, envelop correlation coefficient (ECC, diversity gain (DG, and the total efficiency have been simulated to verify the reliability and the validity of the MIMO system in both parallel and orthogonal configurations. The experimental results are also provided and compared for the mutual coupling with simulated results. An adequate match between the measured and simulated results is achieved.

Space-time adaptive decision feedback neural receivers with data selection for high-data-rate users in DS-CDMA systems.

Science.gov (United States)

de Lamare, Rodrigo C; Sampaio-Neto, Raimundo

2008-11-01

A space-time adaptive decision feedback (DF) receiver using recurrent neural networks (RNNs) is proposed for joint equalization and interference suppression in direct-sequence code-division multiple-access (DS-CDMA) systems equipped with antenna arrays. The proposed receiver structure employs dynamically driven RNNs in the feedforward section for equalization and multiaccess interference (MAI) suppression and a finite impulse response (FIR) linear filter in the feedback section for performing interference cancellation. A data selective gradient algorithm, based upon the set-membership (SM) design framework, is proposed for the estimation of the coefficients of RNN structures and is applied to the estimation of the parameters of the proposed neural receiver structure. Simulation results show that the proposed techniques achieve significant performance gains over existing schemes.

Modeling of compact loop antennas

International Nuclear Information System (INIS)

Baity, F.W.

1987-01-01

A general compact loop antenna model which treats all elements of the antenna as lossy transmission lines has been developed. In addition to capacitively-tuned resonant double loop (RDL) antennas the model treats stub-tuned resonant double loop antennas. Calculations using the model have been compared with measurements on full-scale mockups of resonant double loop antennas for ATF and TFTR in order to refine the transmission line parameters. Results from the model are presented for RDL antenna designs for ATF, TFTR, Tore Supra, and for the Compact Ignition Tokamak

Multiple Access Interference Reduction Using Received Response Code Sequence for DS-CDMA UWB System

Science.gov (United States)

Toh, Keat Beng; Tachikawa, Shin'ichi

This paper proposes a combination of novel Received Response (RR) sequence at the transmitter and a Matched Filter-RAKE (MF-RAKE) combining scheme receiver system for the Direct Sequence-Code Division Multiple Access Ultra Wideband (DS-CDMA UWB) multipath channel model. This paper also demonstrates the effectiveness of the RR sequence in Multiple Access Interference (MAI) reduction for the DS-CDMA UWB system. It suggests that by using conventional binary code sequence such as the M sequence or the Gold sequence, there is a possibility of generating extra MAI in the UWB system. Therefore, it is quite difficult to collect the energy efficiently although the RAKE reception method is applied at the receiver. The main purpose of the proposed system is to overcome the performance degradation for UWB transmission due to the occurrence of MAI during multiple accessing in the DS-CDMA UWB system. The proposed system improves the system performance by improving the RAKE reception performance using the RR sequence which can reduce the MAI effect significantly. Simulation results verify that significant improvement can be obtained by the proposed system in the UWB multipath channel models.

The Antenna Bride and Bridegroom

Science.gov (United States)

2007-03-01

northern Chile, will provide astronomers with the world's most advanced tool for exploring the Universe at millimetre and submillimetre wavelengths. ALMA will detect fainter objects and be able to produce much higher-quality images at these wavelengths than any previous telescope system. Scientists are eager to use this transformational capability to study the first stars and galaxies that formed in the early Universe, to learn long-sought details about how stars are formed, and to trace the motion of gas and dust as it whirls toward the surface of newly-formed stars and planets. "The success of this test is fundamental proof that the hardware and software now under development for ALMA will work to produce a truly revolutionary astronomical tool," said Massimo Tarenghi, the ALMA Director. In addition to the leading-edge electronic and electro-optical hardware and custom software that proved itself by producing ALMA's first fringes, the system's antennas are among the most advanced in the world. The stringent requirements for the antennas included extremely precise reflecting surfaces, highly accurate ability to point at desired locations in the sky, and the ability to operate reliably in the harsh, high-altitude environment of the ALMA site. The ALMA Test Facility operates the two prototype antennas built by Alcatel Alenia Space and European Industrial Engineering in Europe, and by VertexRSI (USA). These antennas were evaluated individually at the ATF. Both prototypes were equipped with electronic equipment for receiving, digitizing and transmitting signals to a central facility, where the signals are combined to make the antennas work together as a single astronomical instrument. "The successful achievement of recording the first fringes with two ALMA antennas is certainly an important milestone in the scientific program," said Hans Rykaczewski, the European ALMA Project Manager. "It is encouraging and adds to our motivation to see that the principles of ALMA work - not

On the performance of transmit antenna selection based on shadowing side information

KAUST Repository

Yilmaz, Ahmet Oǧuz; Yilmaz, Ferkan; Alouini, Mohamed-Slim; Kucur, Oǧuz

2013-01-01

In this paper, a transmit antenna selection scheme, which is based on shadowing side information, is investigated. In this scheme, the selected single transmit antenna provides the highest shadowing coefficient between a transmitter and a receiver. By the proposed technique, the frequency of the usage of the feedback channel from the receiver to the transmitter and channel estimation complexity at the receiver can be reduced. We study the performance of our proposed technique, and in the analysis, we consider an independent but not identically distributed generalized-K composite fading model. More specifically, exact and closed-form expressions for the outage probability, the moment-generating function, the moments of signal-to-noise ratio, and the average symbol error probability (SEP) are derived. In addition, asymptotic outage probability and SP expressions are also presented to investigate the diversity order and the array gain. Finally, our theoretical performance results are validated by Monte Carlo simulations. © 2012 IEEE.

Effect of Antenna Type on the Capacity of Body-to-Body Capacity When Using Uniform Power Allocation

KAUST Repository

Ghanem, Khalida; Al-Quwaiee, Hessa; Khan, Imdad; Hall, Peter

2012-01-01

Body-area networks are led to target multimedia applications where high-data rate is involved. In this paper, the characterization of the measured body-to-body channels and the ergodic capacity with uniform power allocation is discussed when using multiple-input multiple-output (MIMO) PIFA and IFA antenna systems. This capacity is compared to the measured belt-head and belt-chest on-body channels using PIFA antennas in the same environment. It is shown that body channels reach less ergodic capacity than the equivalent Rayleigh channel because of the presence of a LOS component. The capacity is the same for the body-to-body case regardless of the antenna and the on-body channels reach better capacity values compared to these former. © 2012 IEEE.

Effect of Antenna Type on the Capacity of Body-to-Body Capacity When Using Uniform Power Allocation

KAUST Repository

Ghanem, Khalida

2012-09-01

Body-area networks are led to target multimedia applications where high-data rate is involved. In this paper, the characterization of the measured body-to-body channels and the ergodic capacity with uniform power allocation is discussed when using multiple-input multiple-output (MIMO) PIFA and IFA antenna systems. This capacity is compared to the measured belt-head and belt-chest on-body channels using PIFA antennas in the same environment. It is shown that body channels reach less ergodic capacity than the equivalent Rayleigh channel because of the presence of a LOS component. The capacity is the same for the body-to-body case regardless of the antenna and the on-body channels reach better capacity values compared to these former. © 2012 IEEE.

Large space antenna concepts for ESGP

Science.gov (United States)

Love, Allan W.

1989-01-01

It is appropriate to note that 1988 marks the 100th anniversary of the birth of the reflector antenna. It was in 1888 that Heinrich Hertz constructed the first one, a parabolic cylinder made of sheet zinc bent to shape and supported by a wooden frame. Hertz demonstrated the existence of the electromagnetic waves that had been predicted theoretically by James Clerk Maxwell some 22 years earlier. In the 100 years since Hertz's pioneering work the field of electromagnetics has grown explosively: one of the technologies is that of remote sensing of planet Earth by means of electromagnetic waves, using both passive and active sensors located on an Earth Science Geostationary Platform (ESEP). For these purposes some exquisitely sensitive instruments were developed, capable of reaching to the fringes of the known universe, and relying on large reflector antennas to collect the minute signals and direct them to appropriate receiving devices. These antennas are electrically large, with diameters of 3000 to 10,000 wavelengths and with gains approaching 80 to 90 dB. Some of the reflector antennas proposed for ESGP are also electrically large. For example, at 220 GHz a 4-meter reflector is nearly 3000 wavelengths in diameter, and is electrically quite comparable with a number of the millimeter wave radiotelescopes that are being built around the world. Its surface must meet stringent requirements on rms smoothness, and ability to resist deformation. Here, however, the environmental forces at work are different. There are no varying forces due to wind and gravity, but inertial forces due to mechanical scanning must be reckoned with. With this form of beam scanning, minimizing momentum transfer to the space platform is a problem that demands an answer. Finally, reflector surface distortion due to thermal gradients caused by the solar flux probably represents the most challenging problem to be solved if these Large Space Antennas are to achieve the gain and resolution required of

Design and Implementation of Dual-Band MIMO Antenna with Low Mutual Coupling Using EBG for Handheld Applications

Directory of Open Access Journals (Sweden)

Duong Thanh Tu

2017-01-01

Full Text Available A dual-band Multiple Input Multiple Output (MIMO antenna system with enhanced isolation for LTE and WLAN applications is proposed. Using a double-rectangular Defected Ground Structure (DGS, the MIMO antenna gets two resonant frequencies of 2.6 GHz and 5.7 GHz with bandwidth of 5.7% and 4.3% respectively. To reduce much more mutual coupling between dual-band MIMO antenna ports, a novel double-side Electromagnetic Band Gap (EBG structure with equivalent circuit model is proposed. Size of t gain of the antenna is getting better, especially at the low band. he EBG unit cell is 8.6x8.6 mm2 that is built on FR4 substrate with height of 1.6 mm, so it is achieved more compact size than conventional EBG structures. With 1x7 EBG structures, the mutual coupling gets -40dB in the low frequency band and -30 dB in the high one with narrow distance of 0.11 from feeding point to feeding point. Furthermore, radiation efficiency as well as gain of the antenna is getting better, especially at the low band.

Multiple relay selection for delay-limited applications

KAUST Repository

Alsharoa, Ahmad M.; Abediseid, Walid; Alouini, Mohamed-Slim

2013-01-01

A multiple relay selection system model that implements the decode-and-forward mode is investigated. All communication nodes are assumed to be equipped by multiple antennas. Furthermore, lattices space-time coded multiple-input multiple-output half

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

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...

Adaptive algorithm based on antenna arrays for radio communication systems

Directory of Open Access Journals (Sweden)

Fedosov Valentin

2017-01-01

Full Text Available Trends in the modern world increasingly lead to the growing popularity of wireless technologies. This is possible due to the rapid development of mobile communications, the Internet gaining high popularity, using wireless networks at enterprises, offices, buildings, etc. It requires advanced network technologies with high throughput capacity to meet the needs of users. To date, a popular destination is the development of spatial signal processing techniques allowing to increase spatial bandwidth of communication channels. The most popular method is spatial coding MIMO to increase data transmission speed which is carried out due to several spatial streams emitted by several antennas. Another advantage of this technology is the bandwidth increase to be achieved without expanding the specified frequency range. Spatial coding methods are even more attractive due to a limited frequency resource. Currently, there is an increasing use of wireless communications (for example, WiFi and WiMAX in information transmission networks. One of the main problems of evolving wireless systems is the need to increase bandwidth and improve the quality of service (reducing the error probability. Bandwidth can be increased by expanding the bandwidth or increasing the radiated power. Nevertheless, the application of these methods has some drawbacks, due to the requirements of biological protection and electromagnetic compatibility, the increase of power and the expansion of the frequency band is limited. This problem is especially relevant in mobile (cellular communication systems and wireless networks operating in difficult signal propagation conditions. One of the most effective ways to solve this problem is to use adaptive antenna arrays with weakly correlated antenna elements. Communication systems using such antennas are called MIMO systems (Multiple Input Multiple Output multiple input - multiple outputs. At the moment, existing MIMO-idea implementations do not

Spectrum sensing using single-radio switched-beam antenna systems

DEFF Research Database (Denmark)

Tsakalaki, Elpiniki; Wilcox, David; De Carvalho, Elisabeth

2012-01-01

of the reactive loads rotate the narrowband beampattern to different angular positions dividing the whole space around the cognitive receiver into several angular subspaces. The beampattern directionality leverages the performance of spectrum sensing algorithms like the energy detection by enhancing the receive......The paper describes spectrum sensing using single-radio switched-beam arrays with reactance-loaded parasitic elements. At a given frequency, the antenna's loading conditions (reactive loads) are optimized for maximum average beamforming gain in the beampattern look direction. Circular permutations...

Hyperbolic Positioning with Antenna Arrays and Multi-Channel Pseudolite for Indoor Localization

Directory of Open Access Journals (Sweden)

Kenjirou Fujii

2015-09-01

Full Text Available A hyperbolic positioning method with antenna arrays consisting of proximately-located antennas and a multi-channel pseudolite is proposed in order to overcome the problems of indoor positioning with conventional pseudolites (ground-based GPS transmitters. A two-dimensional positioning experiment using actual devices is conducted. The experimental result shows that the positioning accuracy varies centimeter- to meter-level according to the geometric relation between the pseudolite antennas and the receiver. It also shows that the bias error of the carrier-phase difference observables is more serious than their random error. Based on the size of the bias error of carrier-phase difference that is inverse-calculated from the experimental result, three-dimensional positioning performance is evaluated by computer simulation. In addition, in the three-dimensional positioning scenario, an initial value convergence analysis of the non-linear least squares is conducted. Its result shows that initial values that can converge to a right position exist at least under the proposed antenna setup. The simulated values and evaluation methods introduced in this work can be applied to various antenna setups; therefore, by using them, positioning performance can be predicted in advance of installing an actual system.

Monitoring of the MU radar antenna pattern by Satellite Ohzora (EXOS-C)

Science.gov (United States)

Sato, T.; Inooka, Y.; Fukao, S.; Kato, S.

1986-01-01

As the first attempt among MST (mesosphere stratosphere troposphere) type radars, the MU (middle and upper atmosphere) radar features an active phased array system. Unlike the conventional large VHF radars, in which output power of a large vacuum tube is distributed to individual antenna elements, each of 475 solid state power amplifier feeds each antenna element. This system configuration enables very fast beam steering as well as various flexible operations by dividing the antenna into independent subarrays, because phase shift and signal division/combination are performed at a low signal level using electronic devices under control of a computer network. The antenna beam can be switched within 10 microsec to any direction within the zenith angle of 30 deg. Since a precise phase alignment of each element is crucial to realize the excellent performance of this system, careful calibration of the output phase of each power amplifier and antenna element was carried out. Among various aircraft which may be used for this purpose artificial satellites have an advantage of being able to make a long term monitoring with the same system. An antenna pattern monitoring system for the MU radar was developed using the scientific satellite OHZORA (EXOS-C). A receiver named MUM (MU radar antenna Monitor) on board the satellite measures a CW signal of 100 to 400 watts transmitted from the MU radar. The principle of the measurement and results are discussed.

Left-handed compact MIMO antenna array based on wire spiral resonator for 5-GHz wireless applications

Science.gov (United States)

Alqadami, Abdulrahman Shueai Mohsen; Jamlos, Mohd Faizal; Soh, Ping Jack; Rahim, Sharul Kamal Abdul; Narbudowicz, Adam

2017-01-01

A compact coplanar waveguide-fed multiple-input multiple-output antenna array based on the left-handed wire loaded spiral resonators (SR) is presented. The proposed antenna consists of a 2 × 2 wire SR with two symmetrical microstrip feed lines, each line exciting a 1 × 2 wire SR. Left-handed metamaterial unit cells are placed on its reverse side and arranged in a 2 × 3 array. A reflection coefficient of less than -16 dB and mutual coupling of less than -28 dB are achieved at 5.15 GHz WLAN band.

The contribution of the Georges Heights Experimental Radar Antenna to Australian radio astronomy

Science.gov (United States)

Orchiston, Wayne; Wendt, Harry

2017-12-01

During the late 1940s and throughout the1950s Australia was one of the world’s foremost astronomical nations owing primarily to the dynamic Radio Astronomy Group within the Commonwealth Scientific and Industrial Organisation’s Division of Radiophysics based in Sydney. The earliest celestial observations were made with former WWII radar antennas and simple Yagi aerials attached to recycled radar receivers, before more sophisticated purpose-built radio telescopes of various types were designed and developed. One of the recycled WWII antennas that was used extensively for pioneering radio astronomical research was an experimental radar antenna that initially was located at the Division’s short-lived Georges Heights Field Station but in 1948 was relocated to the new Potts Hill Field Station in suburban Sydney. In this paper we describe this unique antenna, and discuss the wide-ranging solar, galactic and extragalactic research programs that it was used for.

Modeling and Control of the Redundant Parallel Adjustment Mechanism on a Deployable Antenna Panel

Directory of Open Access Journals (Sweden)

Lili Tian

2016-10-01

Full Text Available With the aim of developing multiple input and multiple output (MIMO coupling systems with a redundant parallel adjustment mechanism on the deployable antenna panel, a structural control integrated design methodology is proposed in this paper. Firstly, the modal information from the finite element model of the structure of the antenna panel is extracted, and then the mathematical model is established with the Hamilton principle; Secondly, the discrete Linear Quadratic Regulator (LQR controller is added to the model in order to control the actuators and adjust the shape of the panel. Finally, the engineering practicality of the modeling and control method based on finite element analysis simulation is verified.

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.

A novel paradigm for high isolation in multiple antenna systems with user's influence

DEFF Research Database (Denmark)

Pelosi, Mauro; Pedersen, Gert Frølund; Knudsen, Mikael Bergholz

2010-01-01

(UMTS) bands are investigated, showing also the influence of different hand phantoms in average use trough Finite-Difference TimeDomain (FDTD) simulations. It is confirmed that the way a mobile phone is held is very important in determining the amount of absorption loss, detuning and antenna isolation...

Four-to-one power combiner for 20 GHz phased array antenna using RADC MMIC phase shifters

Science.gov (United States)

1991-01-01

The design and microwave simulation of two-to-one microstrip power combiners is described. The power combiners were designed for use in a four element phase array receive antenna subarray at 20 GHz. Four test circuits are described which were designed to enable testing of the power combiner and the four element phased array antenna. Test Circuit 1 enables measurement of the two-to-one power combiner. Test Circuit 2 enables measurement of the four-to-one power combiner. Test Circuit 3 enables measurement of a four element antenna array without phase shifting MMIC's in order to characterize the power combiner with the antenna patch-to-microstrip coaxial feedthroughs. Test circuit 4 is the four element phased array antenna including the RADC MMIC phase shifters and appropriate interconnects to provide bias voltages and control phase bits.

An Application of the "Virtual Spacecraft" Concept in Evaluation of the Mars Pathfinder Lander Low Gain Antenna

Science.gov (United States)

Pogorzelski, R. J.; Beckon, R. J.

1997-01-01

The virtual spacecraft concept is embodied in a set of subsystems, either in the form of hardware or computational models, which together represent all, or a portion of, a spacecraft. For example, the telecommunications transponder may be a hardware prototype while the propulsion system may exist only as a simulation. As the various subsystems are realized in hardware, the spacecraft becomes progressively less virtual. This concept is enabled by JPL's Mission System Testbed which is a set of networked workstations running a message passing operating system called "TRAMEL" which stands for Task Remote Asynchronous Message Exchange Layer. Each simulation on the workstations, which may in fact be hardware controlled by the workstation, "publishes" its operating parameters on TRAMEL and other simulations requiring those parameters as input may "subscribe" to them. In this manner, the whole simulation operates as a single virtual system. This paper describes a simulation designed to evaluate a communications link between the earth and the Mars Pathfinder Lander module as it descends under a parachute through the Martian atmosphere toward the planet's surface. This link includes a transmitter and a low gain antenna on the spacecraft and a receiving antenna and receiver on the earth as well as a simulation of the dynamics of the spacecraft. The transmitter, the ground station antenna, the receiver and the dynamics are all simulated computationally while the spacecraft antenna is implemented in hardware on a very simple spacecraft mockup. The dynamics simulation is a record of one output of the ensemble of outputs of a Monte Carlo simulation of the descent. Additionally, the antenna/spacecraft mock-up system was simulated using APATCH, a shooting and bouncing ray code developed by Demaco, Inc. The antenna simulation, the antenna hardware, and the link simulation are all physically located in different facilities at JPL separated by several hundred meters and are linked via

The Diversity-Multiplexing Tradeoff of Secret-Key Agreement over Multiple-Antenna Channels

KAUST Repository

Zorgui, Marwen; Rezki, Zouheir; Alomair, Basel; Alouini, Mohamed-Slim

2015-01-01

We study the problem of secret-key agreement between two legitimate parties, Alice and Bob, in presence an of eavesdropper Eve. There is a public channel with unlimited capacity that is available to the legitimate parties and is also observed by Eve. Our focus is on Rayleigh fading quasi-static channels. The legitimate receiver and the eavesdropper are assumed to have perfect channel knowledge of their channels. We study the system in the high-power regime. First, we define the secret-key diversity gain and the secret-key multiplexing gain. Second, we establish the secret-key diversity multiplexing tradeoff (DMT) under no channel state information (CSI) at the transmitter (CSI-T). The eavesdropper is shown to “steal” only transmit antennas. We show that, likewise the DMT without secrecy constraint, the secret-key DMT is the same either with or without full channel state information at the transmitter. This insensitivity of secret-key DMT toward CSI-T features a fundamental difference between secret-key agreement and the wiretap channel, in which secret DMT depends heavily on CSI-T. Finally, we present several secret-key DMT-achieving schemes in case of full CSI-T. We argue that secret DMT-achieving schemes are also key DMT-achieving. Moreover, we show formally that artificial noise (AN), likewise zero-forcing (ZF), is DMT-achieving. We also show that the public feedback channel improves the outage performance without having any effect on the DMT.

The Diversity-Multiplexing Tradeoff of Secret-Key Agreement over Multiple-Antenna Channels

KAUST Repository

Zorgui, Marwen

2015-10-26

We study the problem of secret-key agreement between two legitimate parties, Alice and Bob, in presence an of eavesdropper Eve. There is a public channel with unlimited capacity that is available to the legitimate parties and is also observed by Eve. Our focus is on Rayleigh fading quasi-static channels. The legitimate receiver and the eavesdropper are assumed to have perfect channel knowledge of their channels. We study the system in the high-power regime. First, we define the secret-key diversity gain and the secret-key multiplexing gain. Second, we establish the secret-key diversity multiplexing tradeoff (DMT) under no channel state information (CSI) at the transmitter (CSI-T). The eavesdropper is shown to “steal” only transmit antennas. We show that, likewise the DMT without secrecy constraint, the secret-key DMT is the same either with or without full channel state information at the transmitter. This insensitivity of secret-key DMT toward CSI-T features a fundamental difference between secret-key agreement and the wiretap channel, in which secret DMT depends heavily on CSI-T. Finally, we present several secret-key DMT-achieving schemes in case of full CSI-T. We argue that secret DMT-achieving schemes are also key DMT-achieving. Moreover, we show formally that artificial noise (AN), likewise zero-forcing (ZF), is DMT-achieving. We also show that the public feedback channel improves the outage performance without having any effect on the DMT.

Uniform Circular Antenna Array Applications in Coded DS-CDMA Mobile Communication Systems

National Research Council Canada - National Science Library

Seow, Tian

2003-01-01

...) has greatly increased. This thesis examines the use of an equally spaced circular adaptive antenna array at the mobile station for a typical coded direct sequence code division multiple access (DS-CDMA...

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.

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

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

Performance analysis for W-band antenna alignment using accurate mechanical beam steering

DEFF Research Database (Denmark)

Morales Vicente, Alvaro; Rodríguez Páez, Juan Sebastián; Gallardo, Omar

2017-01-01

This article presents a study of antenna alignment impact on bit error rate for a wireless link between two directive W-band horn antennas where one of them is mechanically steered by a Stewart platform. Such a technique is applied to find the optimal alignment between transmitter and receiver...... with an accuracy of 18 both in azimuth and elevation angles. The maximum degree of misalignment which can be tolerated is also reported for different values of optical power in the generation of W-band signals by photonic up-conversion. (C) 2017 Wiley Periodicals, Inc....

Elevated CPW-Fed Slotted Microstrip Antenna for Ultra-Wideband Application

Directory of Open Access Journals (Sweden)

Chandan Kumar Ghosh

2012-01-01

Full Text Available Elevated-coplanar-waveguide- (ECPW- fed microstrip antenna with inverted “G” slots in the back conductor is presented. It is modeled and analyzed for the application of multiple frequency bands. The changes in radiation and the transmission characteristics are investigated by the introduction of the slots in two different positions at the ground plane (back conductor. The proposed antenna without slots exhibits a stop band from 2.55 GHz to 4.25 GHz while introducing two slots on the back conductor, two adjacent poles appear at central frequencies of 3.0 GHz and 3.9 GHz, respectively, and the antenna shows the ultra-wideband (UWB characteristics. The first pole appears at the central frequency of 3.0 GHz and covers the band width of 950 MHz, and the second pole exists at a central frequency of 3.90 GHz covering a bandwidth of 750 MHz. Experimental result shows that impedance bandwidth of 129% (S11<-10 dB is well achieved when the antenna is excited with both slots. Compared to most of the previously reported ECPW structures, the impedance bandwidth of this antenna is increased and also the size of the antenna becomes smaller and more suitable for many wireless applications like PCS (1850–1990 MHz, WLAN (2.4–2.484 GHz, WiMAX (2.5–2.69 GHz and 5.15–5.85 GHz, and also X-band communication.

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

A Dual Band Additively Manufactured 3D Antenna on Package with Near-Isotropic Radiation Pattern

KAUST Repository

Su, Zhen

2018-04-06

Internet of things (IoT) applications need wireless connectivity on devices with very small footprints, and in RF obscure environments. The antenna for such applications must work on multiple GSM bands (preferred choice for network connectivity), provide near isotropic radiation pattern to maintain orientation insensitive communication, be small in size so that it can be integrated with futuristic miniaturized IoT devices, and be low in cost to be implemented on billions of devices. This paper presents a novel 3D dual band near-isotropic wideband GSM antenna to fulfill these requirements. The antenna has been realized on the package of electronics through additive manufacturing to ensure efficient utilization of available space and lower cost. The proposed antenna consists of a meander line antenna that is folded on the faces of a 3D package with two variations, 0.375λ length for narrowband version and 0.67λ length for the wideband version. Theoretical conditions to achieve near isotropic radiation pattern with bent wire antennas on a 3D surface have been derived. The antenna has been optimized to operate with embedded electronics and a large metallic battery. The antenna provides 8.9% and 34.4% bandwidths, at 900 and 1800 MHz respectively with decent near isotropic radiation behavior.

From antenna to antenna: lateral shift of olfactory memory recall by honeybees.

Science.gov (United States)

Rogers, Lesley J; Vallortigara, Giorgio

2008-06-04

Honeybees, Apis mellifera, readily learn to associate odours with sugar rewards and we show here that recall of the olfactory memory, as demonstrated by the bee extending its proboscis when presented with the trained odour, involves first the right and then the left antenna. At 1-2 hour after training using both antennae, recall is possible mainly when the bee uses its right antenna but by 6 hours after training a lateral shift has occurred and the memory can now be recalled mainly when the left antenna is in use. Long-term memory one day after training is also accessed mainly via the left antenna. This time-dependent shift from right to left antenna is also seen as side biases in responding to odour presented to the bee's left or right side. Hence, not only are the cellular events of memory formation similar in bees and vertebrate species but also the lateralized networks involved may be similar. These findings therefore seem to call for remarkable parallel evolution and suggest that the proper functioning of memory formation in a bilateral animal, either vertebrate or invertebrate, requires lateralization of processing.

From antenna to antenna: lateral shift of olfactory memory recall by honeybees.

Directory of Open Access Journals (Sweden)

Lesley J Rogers

Full Text Available Honeybees, Apis mellifera, readily learn to associate odours with sugar rewards and we show here that recall of the olfactory memory, as demonstrated by the bee extending its proboscis when presented with the trained odour, involves first the right and then the left antenna. At 1-2 hour after training using both antennae, recall is possible mainly when the bee uses its right antenna but by 6 hours after training a lateral shift has occurred and the memory can now be recalled mainly when the left antenna is in use. Long-term memory one day after training is also accessed mainly via the left antenna. This time-dependent shift from right to left antenna is also seen as side biases in responding to odour presented to the bee's left or right side. Hence, not only are the cellular events of memory formation similar in bees and vertebrate species but also the lateralized networks involved may be similar. These findings therefore seem to call for remarkable parallel evolution and suggest that the proper functioning of memory formation in a bilateral animal, either vertebrate or invertebrate, requires lateralization of processing.

Estimating movement and survival rates of a small saltwater fish using autonomous antenna receiver arrays and passive integrated transponder tags

Science.gov (United States)

Rudershausen, Paul J.; Buckel, Jeffery A.; Dubreuil, Todd; O'Donnell, Matthew J.; Hightower, Joseph E.; Poland, Steven J.; Letcher, Benjamin H.

2014-01-01

We evaluated the performance of small (12.5 mm long) passive integrated transponder (PIT) tags and custom detection antennas for obtaining fine-scale movement and demographic data of mummichog Fundulus heteroclitus in a salt marsh creek. Apparent survival and detection probability were estimated using a Cormack Jolly Seber (CJS) model fitted to detection data collected by an array of 3 vertical antennas from November 2010 to March 2011 and by a single horizontal antenna from April to August 2011. Movement of mummichogs was monitored during the period when the array of vertical antennas was used. Antenna performance was examined in situ using tags placed in wooden dowels (drones) and in live mummichogs. Of the 44 tagged fish, 42 were resighted over the 9 mo monitoring period. The in situ detection probabilities of the drone and live mummichogs were high (~80-100%) when the ambient water depth was less than ~0.8 m. Upstream and downstream movement of mummichogs was related to hourly water depth and direction of tidal current in a way that maximized time periods over which mummichogs utilized the intertidal vegetated marsh. Apparent survival was lower during periods of colder water temperatures in December 2010 and early January 2011 (median estimate of daily apparent survival = 0.979) than during other periods of the study (median estimate of daily apparent survival = 0.992). During late fall and winter, temperature had a positive effect on the CJS detection probability of a tagged mummichog, likely due to greater fish activity over warmer periods. During the spring and summer, this pattern reversed possibly due to mummichogs having reduced activity during the hottest periods. This study demonstrates the utility of PIT tags and continuously operating autonomous detection systems for tracking fish at fine temporal scales, and improving estimates of demographic parameters in salt marsh creeks that are difficult or impractical to sample with active fishing gear.

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.

Co-design of on-chip antennas and circuits for a UNII band monolithic transceiver

KAUST Repository

Shamim, Atif

2012-07-28

The surge of highly integrated and multifunction wireless devices has necessitated the designers to think outside the box for solutions that are unconventional. The new trends have provided the impetus for low cost and compact RF System-on-Chip (SoC) approaches [1]. The major advantages of SoC are miniaturization and cost reduction. A major bottleneck to the true realization of monolithic RF SoC transceivers is the implementation of on-chip antennas with circuitry. Though complete integrated transceivers with on-chip antennas have been demonstrated, these designs are generally for high frequencies. Moreover, they either use non-standard CMOS processes or additional fabrication steps to enhance the antenna efficiency, which in turn adds to the cost of the system [2-3]. Another challenge related to the on-chip antennas is the characterization of their radiation properties. Most of the recently reported work (summarized in Table I) shows that very few on-chip antennas are characterized. Our previous work [4], demonstrated a Phase Lock Loop (PLL) based transmitter (TX) with an on-chip antenna. However, the radiation from the on-chip antenna experienced strong interference due to 1) some active circuitry on one side of the chip and 2) the PCB used to mount the chip in the anechoic chamber. This paper presents, for the first time, a complete 5.2 GHz (UNII band) transceiver with separate TX and receiver (RX) antennas. To the author\\'s best knowledge, its size of 3 mm2 is the smallest reported for a UNII band transceiver with two on-chip antennas. Both antennas are characterized for their radiation properties through an on-wafer custom measurement setup. The strategy to co-design on-chip antennas with circuits, resultant trade-offs and measurement challenges have also been discussed. © 2010 IEEE.

Optical wireless link between a nanoscale antenna and a transducing rectenna.

Science.gov (United States)

Dasgupta, Arindam; Mennemanteuil, Marie-Maxime; Buret, Mickaël; Cazier, Nicolas; Colas-des-Francs, Gérard; Bouhelier, Alexandre

2018-05-18

Initiated as a cable-replacement solution, short-range wireless power transfer has rapidly become ubiquitous in the development of modern high-data throughput networking in centimeter to meter accessibility range. Wireless technology is now penetrating a higher level of system integration for chip-to-chip and on-chip radiofrequency interconnects. However, standard CMOS integrated millimeter-wave antennas have typical size commensurable with the operating wavelength, and are thus an unrealistic solution for downsizing transmitters and receivers to the micrometer and nanometer scale. Herein, we demonstrate a light-in and electrical signal-out, on-chip wireless near-infrared link between a 220 nm optical antenna and a sub-nanometer rectifying antenna converting the transmitted optical energy into direct electrical current. The co-integration of subwavelength optical functional devices with electronic transduction offers a disruptive solution to interface photons and electrons at the nanoscale for on-chip wireless optical interconnects.

Hybrid plasmonic bullseye antennas for efficient photon collection

DEFF Research Database (Denmark)

Andersen, Sebastian Kim Hjælm; Bozhevolnyi, Sergey I.; Shalaev, Vladimir M.

2018-01-01

We propose highly efficient hybrid plasmonic bullseye antennas for collecting photon emission from nm sized quantum emitters. In our approach, the emitter radiation is coupled to surface plasmon polaritons that are consequently converted into highly directional out-of-plane emission. The proposed...... configuration consists of a high-index titania bullseye grating separated from a planar silver film by a thin low-index silica spacer layer. Such hybrid systems are theoretically capable of directing 85% of the dipole emission into a 0.9 NA objective, while featuring a spectrally narrow-band tunable decay rate...... stable operation. For experimental characterization of the antenna properties, a fluorescent nanodiamond containing multiple nitrogen vacancy centers (NV-center) was deterministically placed in the bullseye center, using an atomic force microscope. Probing the NV-center fluorescence we demonstrate...

Microwave antenna holography

Science.gov (United States)

Rochblatt, David J.; Seidel, Boris L.

1992-01-01

This microwave holography technique utilizes the Fourier transform relation between the complex far field radiation pattern of an antenna and the complex aperture field distribution. Resulting aperture phase and amplitude distribution data can be used to precisely characterize various crucial performance parameters, including panel alignment, panel shaping, subreflector position, antenna aperture illumination, directivity at various frequencies, and gravity deformation effects. The methodology of data processing presented here was successfully applied to the Deep Space Network (DSN) 34-m beam waveguide antennas. The antenna performance was improved at all operating frequencies by reducing the main reflector mechanical surface rms error to 0.43 mm. At Ka-band (32 GHz), the estimated improvement is 4.1 dB, resulting in an aperture efficiency of 52 percent. The performance improvement was verified by efficiency measurements and additional holographic measurements.

Doubling transmission capacity in optical wireless system by antenna horizontal- and vertical-polarization multiplexing.

Science.gov (United States)

Li, Xinying; Yu, Jianjun; Zhang, Junwen; Dong, Ze; Chi, Nan

2013-06-15

We experimentally demonstrate 2×56 Gb/s two-channel polarization-division-multiplexing quadrature-phase-shift-keying signal delivery over 80 km single-mode fiber-28 and 2 m Q-band (33-50 GHz) wireless link, adopting antenna horizontal- (H-) and vertical-polarization (V-polarization) multiplexing. At the wireless receiver, classic constant-modulus-algorithm equalization based on digital signal processing can realize polarization demultiplexing and remove the crosstalk at the same antenna polarization. By adopting antenna polarization multiplexing, the signal baud rate and performance requirements for optical and wireless devices can be reduced but at the cost of double antennas and devices, while wireless transmission capacity can also be increased but at the cost of stricter requirements for V-polarization. The isolation is only about 19 dB when V-polarization deviation approaches 10°, which will affect high-speed (>50 Gb/s) wireless delivery.

MARBLE (Multiple Antenna Radio-interferometry for Baseline Length Evaluation): Development of a Compact VLBI System for Calibrating GNSS and Electronic Distance Measurement Devices

Science.gov (United States)

Ichikawa, R.; Ishii, A.; Takiguchi, H.; Kimura, M.; Sekido, M.; Takefuji, K.; Ujihara, H.; Hanado, Y.; Koyama, Y.; Kondo, T.; Kurihara, S.; Kokado, K.; Kawabata, R.; Nozawa, K.; Mukai, Y.; Kuroda, J.; Ishihara, M.; Matsuzaka, S.

2012-12-01

We are developing a compact VLBI system with a 1.6-m diameter aperture dish in order to provide reference baseline lengths for calibration. The reference baselines are used to validate surveying instruments such as GPS and EDM and is maintained by the Geospatial Information Authority of Japan (GSI). The compact VLBI system will be installed at both ends of the reference baseline. Since the system is not sensitive enough to detect fringes between the two small dishes, we have designed a new observation concept including one large dish station. We can detect two group delays between each compact VLBI system and the large dish station based on conventional VLBI measurement. A group delay between the two compact dishes can be indirectly calculated using a simple equation. We named the idea "Multiple Antenna Radio-interferometry for Baseline Length Evaluation", or MARBLE system. The compact VLBI system is easy transportable and consists of the compact dish, a new wide-band front-end system, azimuth and elevation drive units, an IF down-converter unit, an antenna control unit (ACU), a counterweight, and a monument pillar. Each drive unit is equipped with a zero-backlash harmonic drive gearing component. A monument pillar is designed to mount typical geodetic GNSS antennas easily and an offset between the GNSS antenna reference point. The location of the azimuth-elevation crossing point of the VLBI system is precisely determined with an uncertainty of less than 0.2 mm. We have carried out seven geodetic VLBI experiments on the Kashima-Tsukuba baseline (about 54 km) using the two prototypes of the compact VLBI system between December 2009 and December 2010. The average baseline length and repeatability of the experiments is 54184874.0 ± 2.4 mm. The results are well consistent with those obtained by GPS measurements. In addition, we are now planning to use the compact VLBI system for precise time and frequency comparison between separated locations.

Initial results for compressive sensing in electronic support receiver systems

CSIR Research Space (South Africa)

Du Plessis, WP

2011-04-01

Full Text Available determined by the antenna and microwave system comprising the transmitter and receiver, while the instantaneous bandwidth is mainly determined by the Analog-to-Digital Converter (ADC) in the receiver. A radar can thus operate at any frequency within its... Electronic/Electromagnetic Support Measures (ESM) was used historically [1], [2]. Modern ES receiver systems are based on digital receivers allowing powerful signal processing techniques to be used [3], [4]. Recent developments in sampling technology...

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.

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 characterist......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...

Optimization of Passive Coherent Receiver System Placement

Science.gov (United States)

2013-09-01

spheroid object with a constant radar cross section (RCS). Additionally, the receiver and transmitters are assumed to be notional isotropic antennae...software- defined radio for equatorial plasma instability studies,” Radio Science, vol. 48, pp. 1–11. Aug. 2013. [2] P. C. Zhang and B. Y. Li, “Passive

Extraordinary electromagnetic transmission by antenna arrays and frequency selective surfaces having compound unit cells with dissimilar elements

Energy Technology Data Exchange (ETDEWEB)

Loui, Hung; Strassner, II, Bernd H.

2018-03-20

The various embodiments presented herein relate to extraordinary electromagnetic transmission (EEMT) to enable multiple inefficient (un-matched) but coupled radiators and/or apertures to radiate and/or pass electromagnetic waves efficiently. EEMT can be utilized such that signal transmission from a plurality of antennas and/or apertures occurs at a transmission frequency different to transmission frequencies of the individual antennas and/or aperture elements. The plurality of antennas/apertures can comprise first antenna/aperture having a first radiating area and material(s) and second antenna/aperture having a second radiating area and material(s), whereby the first radiating/aperture area and second radiating/aperture area can be co-located in a periodic compound unit cell. Owing to mutual coupling between the respective antennas/apertures in their arrayed configuration, the transmission frequency of the array can be shifted from the transmission frequencies of the individual elements. EEMT can be utilized for an array of evanescent of inefficient radiators connected to a transmission line(s).

Iterative MIMO Turbo Multiuser Detection and Equalization for STTrC-Coded Systems with Unknown Interference

Directory of Open Access Journals (Sweden)

Veselinovic Nenad

2004-01-01

Full Text Available Iterative multiuser detection in a single-carrier broadband multiple-input multiple-output (MIMO system is studied in this paper. A minimum mean squared error (MMSE low-complexity multiuser receiver is derived for space-division multiple-access (SDMA space-time trellis-coded (STTrC systems in frequency-selective fading channels. The receiver uses MMSE filtering to jointly detect several transmit antennas of the user of interest, while the interference from the undetected transmit antennas, cochannel interference (CCI, and intersymbol interference (ISI are all cancelled by the soft cancellation. The performances of two extreme receiver cases are evaluated. In the first case, only one transmit antenna of the user of interest is detected at a time and the remaining ones are cancelled by soft cancellation. In the second case, all the transmit antennas are detected jointly. The comparison of the two cases shows improvement with the latter one, both in single-user and multiuser communications and in the presence of unknown cochannel interference (UCCI. It is further shown that in the multiuser case, the proposed receivers approach the corresponding single-user bounds. The number of receive antenna elements required to achieve single-user bound is thereby equal to the number of users and not to the total number of transmit antennas.

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.

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

The principles of radio engineering and antennas. II Antennas (2nd revised and enlarged edition)

Science.gov (United States)

Belotserkovskii, G. B.

This book represents the second part of a textbook for technical schools. The characteristics and parameters of antennas are considered along with transmission lines, the theory of single dipoles and radiator systems, and the technological realization of elements and units of the antenna-feeder system, taking into account filters and multiport networks for microwave communications applications, and ferrite circulators and isolators. The first edition of this textbook was published in 1969. For the current edition, the material in the first edition has been revised, and new material has been introduced. Much attention is given to microwave antennas, including, in particular, arrays with electrical scanning characteristics. Other topics discussed are related to the general principles of antennas, the matching of the impedance of transmission lines, the elements of transmission lines, aperture-type antennas for microwaves, and the functional characteristics of antennas for ultrashort waves.

Wireless interrogation of passive antenna sensors

International Nuclear Information System (INIS)

Deshmukh, S; Huang, H

2010-01-01

Recently, we discovered that the resonant frequency of a microstrip patch antenna is sensitive to mechanical strains or crack presence in the ground plane. Based on this principle, antenna sensors have been demonstrated to measure strain and detect crack in metallic structures. This paper presents a wireless method to remotely interrogate a dual-frequency antenna sensor. An interrogation horn antenna was used to irradiate the antenna sensor with a linear chirp microwave signal. By implementing a light-activated switch at the sensor node and performing signal processing of the backscattered signals, the resonant frequencies of the antenna sensor along both polarizations can be measured remotely. Since the antenna sensor does not need a local power source and can be interrogated wirelessly, electric wiring can be eliminated. The sensor implementation, the signal processing and the experimental setup that validate the remote interrogation of the antenna sensor are presented. A power budget model has also been established to estimate the maximum interrogation range

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.

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.

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...

DEA deformed stretchable patch antenna

International Nuclear Information System (INIS)

Jiang, X-J; Jalali Mazlouman, S; Menon, C; Mahanfar, A; Vaughan, R G

2012-01-01

A stretchable patch antenna (SPA) whose frequency is tuned by a planar dielectric elastomer actuator (DEA) is presented in this paper. This mechanically reconfigurable antenna system has a configuration resembling a pre-stretched silicone belt. Part of the belt is embedded with a layer of conductive liquid metal to form the patch antenna. Part of the belt is sandwiched between conductive electrodes to form the DEA. Electrical activation of the DEA results in a contraction of the patch antenna, and as a result, in a variation of its resonance frequency. Design and fabrication steps of this system are presented. Measurement results for deformation, resonance frequency variation and efficiency of the patch antenna are also presented. (paper)

The ICRF antennas for TFTR

International Nuclear Information System (INIS)

Hoffman, D.J.; Colestock, P.L.; Gardner, W.L.; Hosea, J.C.; Nagy, A.; Stevens, J.; Swain, D.W.; Wilson, J.R.

1988-01-01

Two compact loop antennas have been designed to provide ion cyclotron resonant frequency (ICRF) heating for TFTR. The antennas can convey a total of 10 MW to accomplish core heating in either high-density or high-temperature plasmas. The near-term goal of heating TFTR plasmas and the longer-term goals of ease in handling (for remote maintenance) and high reliability (in an inaccessible tritium tokamak environment) were major considerations in the antenna designs. The compact loop configuration facilitates handling because the antennas fit completely through their ports. Conservative design and extensive testing were used to attain the reliability required for TFTR. This paper summarizes how these antennas will accomplish these goals. 5 figs, 1 tab

Antenna Parts and Waveguide Transmission Line of Short Pulse Radar System Design

Directory of Open Access Journals (Sweden)

M. E. Golubcov

2014-01-01

Full Text Available The main point of this research was работы являлось to create a stand to explore the application of short pulse radio signals in radar. The stand consists of antenna and waveguide elements. Each element out to guarantee operation in X-band with 10 percent working bank and 5 percent instantaneous bandwidth and the power output gotta be 1.5 kW. The form of the antenna beam patten need to be similar to cosecant pattern Side-lobe level need to be less than -25 dB. Background level got to be at least -30 dB. Wave friction, which is radiated from the antenna aperture, got to simultaneous formed in a space.As the most easily realizing variant of such antenna cutting parabolic mirror antenna with offset irradiator was chosen. The irradiator phase centre is shifted from the focal point of the paraboloid to form a cosecant pattern. Method of physical optics is used for the analysis of antennas. Calculating pattern of horn irradiator and mirror antenna which were met the requirements was received. The construction choice was limited by the preproduction possibilities, mass and dimensions. Mirror antenna consists of skeleton framing with mirroring elements which are fixing on it. Mirroring plane is multiplex and consists off rectangular planes made by hydroforming method. Antenna was tested and adjusted at the antenna darkroom after fabricating. The results were meted requirements.Besides the mirror antenna and the horn antenna waveguide elements, waveguide bends and rotating joints were calculated, manufactured and researched. All calculations included the manufacturers tolerances, technological corner R etc. As the construction base of rotating joint coaxial waveguide was chosen. The decision on the one hand: let keep the axial symmetry of excited wave at rotating part of the waveguide, on the other hand there’s no necessary to apply resonant rings, which are plug into dielectric beads for the transition from rotating ring part to

TOPLHA: an accurate and efficient numerical tool for analysis and design of LH antennas

International Nuclear Information System (INIS)

Milanesio, D.; Lancellotti, V.; Meneghini, O.; Maggiora, R.; Vecchi, G.; Bilato, R.

2007-01-01

Auxiliary ICRF heating systems in tokamaks often involve large complex antennas, made up of several conducting straps hosted in distinct cavities that open towards the plasma. The same holds especially true in the LH regime, wherein the antennas are comprised of arrays of many phased waveguides. Upon observing that the various cavities or waveguides couple to each other only through the EM fields existing over the plasma-facing apertures, we self-consistently formulated the EM problem by a convenient set of multiple coupled integral equations. Subsequent application of the Method of Moments yields a highly sparse algebraic system; therefore formal inversion of the system matrix happens to be not so memory demanding, despite the number of unknowns may be quite large (typically 10 5 or so). The overall strategy has been implemented in an enhanced version of TOPICA (Torino Polytechnic Ion Cyclotron Antenna) and in a newly developed code named TOPLHA (Torino Polytechnic Lower Hybrid Antenna). Both are simulation and prediction tools for plasma facing antennas that incorporate commercial-grade 3D graphic interfaces along with an accurate description of the plasma. In this work we present the new proposed formulation along with examples of application to real life large LH antenna systems

TCM Analysis of Defected Ground Structures for MIMO Antenna Designs in Mobile Terminals

KAUST Repository

Ghalib, Asim

2017-08-14

In this paper, the theory of characteristic modes (TCM) is used for the first time to analyze the behavior of defected ground structures (DGS) when added to antenna designs. A properly designed DGS introduces currents opposite in direction to the original characteristic modes (CM) currents thus reducing mutual coupling. TCM is also applied to multiple-inputmultiple- output (MIMO) antenna systems to develop a systematic approach that can predict whether the isolation can be enhanced further or not. For this purpose two 4-element and one 2-element MIMO designs, i.e. monopole and planar inverted-F antennas (PIFA) are studied. The addition of different antenna elements affects the CM significantly as well as differently. Some of the CM excited on the antenna surface contribute to the coupling between the antenna ports that is why they can be classified as coupling modes. To improve the isolation, the DGS should be introduced at certain locations that blocks the coupling modes but at the same time does not affect the non-coupling modes. If their is no such location or the current on the surface of the chassis for coupling and non-coupling modes is approximately same, the isolation cannot be enhanced further. Using this approach, isolation was improved on an average by 11 dB in all the designs considered, giving the most isolation enhancement following a systematic way compared to other works.

Adaptive Antenna System for Both 4G LTE and 5G Cellular Systems

Science.gov (United States)

Henderson, Kendrick Q. T.

Given the steep increase in the use of mobile communication systems, the current 4G/LTE (Long Term Evolution), cellular system will not be able to handle the increase in data. It is estimated that by 2020 the bandwidth requirements will be 10 times greater than what LTE can sustain. A new 5th generation (5G) communication system has been proposed to meet this demand. The physical layer or the antenna is the most critical part of any wireless communication systems as it is the interface between the free space medium and an electrical circuit. It sets the margin for almost all design parameters in the system such as the system noise and bandwidth. Several interactions of antennas have been proposed over the years for cellular services. These antennas are of various geometries, bandwidths, and radiation patterns with almost all having linear polarization. This thesis attempts to solve the multiple LTE antenna problem by creating a simple antenna that covers most of the LTE bands (850-2700 MHz) as well as introducing an antenna system at the 28 GHz 5G band. This allows for a greater educated hypothesis into what 5G can offer at the physical layer. The proposed concept will provide a solution to the co-existence problem of upcoming 5G wireless systems to be interoperable with existing 4G/LTE system.

The 136 MHZ/400 MHz earth station antenna-noise temperature prediction program for RAE-B

Science.gov (United States)

Taylor, R. E.; Fee, J. J.; Chin, M.

1972-01-01

A simulation study was undertaken to determine the 136 MHz and 400 MHz noise temperature of the ground network antennas which will track the RAE-B satellite during data transmission periods. Since the noise temperature of the antenna effectively sets the signal-to-noise ratio of the received signal, a knowledge of SNR will be helpful in locating the optimum time windows for data transmission during low noise periods. Antenna noise temperatures will be predicted for selected earth-based ground stations which will support RAE-B. Telemetry data acquisition will be at 400 MHz; tracking support at 136 MHz will be provided by the Goddard Range and Range Rate (RARR) stations. The antenna-noise temperature predictions will include the effects of galactic-brightness temperature, the sun, and the brightest radio stars. Predictions will cover the ten-month period from March 1, 1973 to December 31, 1973.

Experiments with dipole antennas

International Nuclear Information System (INIS)

Kraftmakher, Yaakov

2009-01-01

Employment of a data-acquisition system for data collection and calculations makes experiments with antennas more convenient and less time consuming. The determined directional patterns of the dipole antennas of different lengths are in reasonable agreement with theory. The enhancement of the signal by using a reflector is demonstrated, and a variant of the Yagi-Uda antenna is explored. The experiments are suitable as laboratory works and classroom demonstrations, and are attractive for student projects.

Wireless Energy Harvesting Using Signals from Multiple Fading Channels

KAUST Repository

Chen, Yunfei

2017-08-01

In this paper, we study the average, the probability density function and the cumulative distribution function of the harvested power. In the study, the signals are transmitted from multiple sources. The channels are assumed to be either Rician fading or Gamma-shadowed Rician fading. The received signals are then harvested by using either a single harvester for simultaneous transmissions or multiple harvesters for transmissions at different frequencies, antennas or time slots. Both linear and nonlinear models for the energy harvester at the receiver are examined. Numerical results are presented to show that, when a large amount of harvested power is required, a single harvester or the linear range of a practical nonlinear harvester are more efficient, to avoid power outage. Further, the power transfer strategy can be optimized for fixed total power. Specifically, for Rayleigh fading, the optimal strategy is to put the total power at the source with the best channel condition and switch off all other sources, while for general Rician fading, the optimum magnitudes and phases of the transmitting waveforms depend on the channel parameters.

Group Delay of High Q Antennas

DEFF Research Database (Denmark)

Bahramzy, Pevand; Pedersen, Gert Frølund

2013-01-01

Group Delay variations versus frequency is an essential factor which can cause distortion and degradation in the signals. Usually this is an issue in wideband communication systems, such as satellite communication systems, which are used for transmitting wideband data. However, group delay can also...... 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....

Control System and Tests for the 13.2-m RAEGE Antenna at Yebes

Science.gov (United States)

de Vicente, P.; Bolaño, R.; Barbas, L.

2014-12-01

The RAEGE network is being deployed. The antenna at the Yebes Observatory is the first one in the network, and its construction finished in October 2013. During the construction phase, the remote control system for the antenna and the receivers was developed, and during the commisioning time the software was tested by MT-Mechatronics. As a result, both the control system from MT-Mechatronics and the remote control system by the IGN-CDT were debugged. We have tested the basic functionality of the antenna operated as a single dish telescope. First light at S, X, and Ka band was achieved on February 10^{th}. Afterwards a pointing model for the whole sky was determined, together with an optimum focus position as a function of elevation. Commisioning is not finished yet, and the antenna will be totally delivered to the IGN-CDT in the next weeks. VLBI equipment will be installed within three months, and VLBI observations are foreseen by the end of 2014. In this paper, we provide an overview of the control system and of the main results achieved.

Development and evaluation of a boat-mounted RFID antenna for monitoring freshwater mussels

Science.gov (United States)

Fischer, Jesse R.; Neebling, Travis E.; Quist, Michael C.

2012-01-01

Development of radio frequency identification (RFID) technology and passive integrated transponder (PIT) tags has substantially increased the ability of researchers and managers to monitor populations of aquatic organisms. However, use of transportable RFID antenna systems (i.e., backpack-mounted) is currently limited to wadeable aquatic environments (system regardless of tag orientation. However, burrowed mussels may require multiple passes to increase detection that would be influenced by depth, tag orientation, and tag size. Construction of the boat-mounted antenna was relatively low in cost (traditional mussel sampling techniques (diving, snorkeling) in nonwadeable habitats.