Sample records for adaptive antenna radio-fiber

  1. Variable Delay With Directly-Modulated R-SOA and Optical Filters for Adaptive Antenna Radio-Fiber Access

    Prince, Kamau; Presi, Marco; Chiuchiarelli, Andrea;


    on a directly-modulated reflective emiconductor amplifier (R-SOA) and exploits the interplay between transmission-line dispersion and tunable optical filtering to achieve flexible true time delay, with $2pi$ beam steering at the different antennas. The system was characterized, then successfully...

  2. Adaptive antennas and receivers

    Weiner, Melvin M


    In our modern age of remote sensing, wireless communication, and the nearly endless list of other antenna-based applications, complex problems require increasingly sophisticated solutions. Conventional antenna systems are no longer suited to high-noise or low-signal applications such as intrusion detection. Detailing highly effective approaches to non-Gaussian weak signal detection, Adaptive Antennas and Receivers provides an authoritative introduction to state-of-the-art research on the modeling, testing, and application of these technologies.Edited by innovative researcher and eminent expert

  3. A Fast Adaptive Receive Antenna Selection Method in MIMO System

    Chaowei Wang


    Full Text Available Antenna selection has been regarded as an effective method to acquire the diversity benefits of multiple antennas while potentially reduce hardware costs. This paper focuses on receive antenna selection. According to the proportion between the numbers of total receive antennas and selected antennas and the influence of each antenna on system capacity, we propose a fast adaptive antenna selection algorithm for wireless multiple-input multiple-output (MIMO systems. Mathematical analysis and numerical results show that our algorithm significantly reduces the computational complexity and memory requirement and achieves considerable system capacity gain compared with the optimal selection technique in the same time.

  4. Factors in the design of adaptive antennas

    Barton, P.

    A brief review of adaptive antenna technology is given, and two topic areas are addressed. The first is concerned with the general difficulties encountered in design, in particular the avoidance of nulling wanted signals, the provision of an adequate rate of convergence towards a desired characteristic, and the degradation of null depths caused by the proximity of the platform and by dispersion in the array and receiving channels. The second topic concerns specific design approaches. Closed loop processors, in which the array output is sensed in order to provide a drive to the weight networks, are exemplified by a feedback loop correlator design and a weight perturbation technique. An example of open-loop control of weight values is also included, and its lack of self-correction is shown to be disadvantageous compared to the closed loop approach. Advanced methods, associated with sample matrix inversion, are also summarized.

  5. A Reconfigurable Spiral Antenna for Adaptive MIMO Systems

    Cetiner Bedri A; Qian J. Y.; Li G. P.; De Flaviis F


    We present a reconfigurable spiral antenna for use in adaptive MIMO systems. The antenna is capable of changing the sense of polarization of the radiated field. It is fabricated by using an RF-MEMS technology compatible with microwave laminate substrates developed within the author's group. The proposed antenna structure is built on a number of rectangular-shaped bent metallic strips interconnected to each other with RF-MEMS actuators. Two senses of polarization, RHCP and LHCP, are achiev...

  6. Adaptive cancellation of Es layer interference using auxiliary horizontal antennas

    Zhao Long; Zhang Ning


    Based on a dual-polarization high-frequency wave radar system, an adaptive system using horizontal antennas for the suppression of the Es layer interference (ELI) is described. The data received from the horizontal antennas were correlated with the data received from the Vertically Polarized Antennas (VPAs) to estimate and cancel the interference adaptively in the VPAs. Suppressing the interference after each coherent integration time interval, about 25 dB signal-to-interference ratio is expected with the experimentally derived data.

  7. A Simple Digital Adaptive Antenna Based on Undersampling

    Z. Raida; P. Pomenka


    A simple adaptive antenna based on the pilot signal method is described in the presented paper. The system consists of coherent mixers, which shift RF signals into IF band, of sampling amplifiers and A/D converters, which digitalize signals, and of PC, which performs the adaptive control. Functionality of the system is verified by a simple experiment.

  8. Antenna subset selection at multi-antenna relay with adaptive modulation

    Choi, Seyeong


    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.

  9. Radio propagation and adaptive antennas for wireless communication networks

    Blaunstein, Nathan


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

  10. Applications of trimode waveguide feeds in adaptive virtual array antennas

    Allahgholi Pour, Z.; Shafai, Lotfollah


    This paper presents the formation of an adaptive virtual array antenna in a symmetric parabolic reflector antenna illuminated by trimode circular waveguide feeds with different mode alignments. The modes of interest are the TE11, TE21, and TM01 type modes. The terms TE and TM stand for the transverse electric and transverse magnetic modes, respectively. By appropriately exciting these modes and varying the mode orientations inside the primary feed, the effective source of radiation is displaced on the reflector aperture, while the resulting secondary patterns remain axial. Different antenna parameters such as gain, cross polarization, and phase center locations are investigated. It is demonstrated that the extra third mode facilitates the formation of symmetric virtual array antennas with reasonable cross polarization discriminations at the diagonal plane.

  11. A Reconfigurable Spiral Antenna for Adaptive MIMO Systems

    Qian JY


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

  12. Comparison of Adaptive Antenna Arrays Controlled by Gradient Algorithms

    Z. Raida


    Full Text Available The paper presents the Simple Kalman filter (SKF that has been designed for the control of digital adaptive antenna arrays. The SKF has been applied to the pilot signal system and the steering vector one. The above systems based on the SKF are compared with adaptive antenna arrays controlled by the classical LMS and the Variable Step Size (VSS LMS algorithms and by the pure Kalman filter. It is shown that the pure Kalman filter is the most convenient for the control of the adaptive arrays because it does not require any a priori information about noise statistics and excels in high rate of convergence and low misadjustment. Extremely high computational requirements are drawback of this filter. Hence, if low computational power of signal processors is at the disposal, the SKF is recommended to be used. Computational requirements of the SKF are of the same order as the classical LMS algorithm exhibits. On the other hand, all the important features of the pure Kalman filter are inherited by the SKF. The paper shows that presented Kalman filters can be regarded as special gradient algorithms. That is why they can be compared with the LMS family.

  13. Optical implementation for adaptive beamforming of array antenna

    Liu, Ming; Shi, Xiang quan


    It is difficult for the traditional phased array radar to process large array-element and high time-bandwidth-product signal in real time. An optical architecture of implement true time delay adaptive beamforming based on Stimulate Photon Echoes(SPE) is introduced. The principle of how to implement a true time delay based on SPE phenomenon with its theory models is established. the method of how to implement variable time delays using laser beams modulated by linear frequency chirped pulses is discussed, the relationship between chirp bandwidth and delay step is demonstrated by simulation results. As a result, it allows to filter thousands of simultaneous AOAs with 30 GHz dynamically in both spatial and spectral domains, which can be used to adaptively steer a large RF phased array antenna toward the direction of interest while minimizing the effects of unwanted interference signals.

  14. Methods of Signal Processing for Adaptive Antenna Arrays

    Titarenko, Larysa


    So far there does not exist any theory of adaptive spatial signal processing (ASSP) for signals with uncertain parameters. This monograph is devoted to the development of this theory, which is very important in connection with wide spreading of telecommunications and radio links in the modern society. This theory can be applied for the development of effective radio communications. In the book some original approaches are proposed targeting the development of effective algorithms of ASSP with not exactly known parameters. They include both probabilistic and deterministic approaches for synthesis of robust algorithms of ASSP. The solution of problems also can be reduced to the construction of some operators for the Banach space which is presented in the book.  “Methods of Signal Processing for Adaptive Antenna Arrays” targets professionals, students and PhD students in the area of telecommunications and should be useful for everybody connected with the new information technologies.

  15. Adaptive single-antenna transmit selection with interference suppression

    Radaydeh, Redha Mahmoud Mesleh


    This paper studies the performance of adaptive transmit selection with co-channel interference suppression in multipath fading channels. The adaptive selection algorithms are configured for single-antenna bandwidth-efficient or power-efficient transmission with as low transmit channel estimations as possible. Due to the fact that the number of active co-channel interfering signals and their corresponding powers experience random behavior, the adaptation to channels conditions, assuming uniform buffer and traffic loading, is proposed to be jointly based on the transmit channels instantaneous signal-to-noise ratios (SNRs) and signal-to-interference-plus-noise ratios (SINRs). Two interference cancelation algorithms are considered. The first algorithm assumes that the receiver eliminates the impact of the strongest subset of interferers, whereas the second algorithm suggests random cancelation of interferers to further reduce processing complexity. The impact of outdated ordering of interferers powers on the efficiency of interference cancelation, and the effect of imperfect prediction of transmit channels for desired user adaptation are investigated. Analytical formulations for various performance measures and comparisons between the performance and processing complexity of different adaptation schemes are presented. © 2011 IEEE.

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

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


    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...

  17. Performance Comparison of Symmetric and Offset Reflector Antennas Adaptively Illuminated by Novel Triple Mode Feedhorn

    Satish K. Sharma


    Full Text Available Parabolic symmetric and offset reflector antennas adaptively illuminated using a novel triple-mode feedhorn (TE11+TM01+TE21 with different mode combinations and impedance and radiation performances are presented. The combination of the radiating modes in a feedhorn with proper amplitude and fixed phase values helps in electronically pointing the main beam of the radiating patterns such as that obtained in a beam-steering antenna with limited beam-scan range. This type of radiation performance virtually creates a displaced phase center location for the feedhorn, which, consequently, adaptively illuminates the reflector antenna surface. Impedance-matching bandwidths are preserved for both reflector antennas similar to the case of feedhorn alone. The copolarization gain and peak cross-polarization levels are far better with the offset reflector antenna than the symmetric reflector antenna. Such reflector antennas find applications in ground moving target indicator (GMTI and space based radars. The investigation results are solely computed using FEKO full-wave analysis tool.

  18. Wireless personal communications for the 21st century : European technological advances in adaptive antennas

    Tsoulos, GV; Beach, MA; McGeehan, JP


    Adaptive antennas are now regarded by many within the wireless communications industry as a core system component in future-generation mobile networks. In order to promote European research and development in this strategic area, the Commission of the European Community has funded, through the Research into Advanced Communications in Europe, RACE, and now the Advanced Communications Technologies and Services, ACTS, programs, the Technology in Smart Antennas for Universal Advanced Mobile Infra...

  19. Experimental Study of a Membrane Antenna Surface Adaptive Control System

    Fang, H.; Quijano, U.; Bach, V.; Hill, J.; Wang, K. W.


    Due to their ultra lightweight and high packaging efficiency, membrane reflectors are getting more and more attentions for mission architectures that need extremely large inspace deployable antennas. However how to maintain the surface shape of a membrane reflector to the instrument precision requirements is a very challenging problem. This experimental study investigated using PVDF membrane piezoelectric material as actuators to control the surface figures of membrane reflectors. The feasibility of this approach is demonstrated by several sets of test results.

  20. Performance Analysis of Blind Beamforming Algorithms in Adaptive Antenna Array in Rayleigh Fading Channel Model

    In this paper, we analyze the performance of adaptive blind algorithms – i.e. Kaiser Constant Modulus Algorithm (KCMA), Hamming CMA (HAMCMA) – with CMA in a wireless cellular communication system using digital modulation technique. These blind algorithms are used in digital signal processor of adaptive antenna to make it smart and change weights of the antenna array system dynamically. The simulation results revealed that KCMA and HAMCMA provide minimum mean square error (MSE) with 1.247 dB and 1.077 dB antenna gain enhancement, 75% reduction in bit error rate (BER) respectively over that of CMA. Therefore, KCMA and HAMCMA algorithms give a cost effective solution for a communication system

  1. Smart antennas

    Godara, Lal Chand


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

  2. MI-NLMS adaptive beamforming algorithm for smart antenna system applications

    MOHAMMAD Tariqul Islam; ZAINOL Abidin Abdul Rashid


    A Matrix Inversion Normalized Least Mean Square (MI-NLMS) adaptive beamforming algorithm was developed for smart antenna application. The MI-NLMS which combined the individual good aspects of Sample Matrix Inversion (SMI) and the Normalized Least Mean Square (NLMS) algorithms is described. Simulation results showed that the less complexity MI-NLMS yields 15 dB improvements in interference suppression and 5 dB gain enhancement over LMS algorithm, converges from the initial iteration and achieves 24% BER improvements at cochannel interference equal to 5. For the case of 4-element uniform linear array antenna, MI-NLMS achieved 76% BER reduction over LMS algorithm.


    S.Venkata Krishnan


    Full Text Available In the recent evolution of wireless technologies, the power management has been a worrying factor. In order to overcome the power shortage, steps are taken to find new kind of energy harvesting methods, power attenuation reduction methods and power saving techniques. Wireless routers even though consume not much of power, battery powered devices require a lot. Omni directional antenna embedded with multiple antennae focusing the beam of radio wave signals in the direction of nodes with least transmission angle can be a solution for this problem which is called as “Smart Antenna”. To reduce power maceration we are going for adaptive and dynamic transmission wherein the transmission angle of antennae is varied in accordance with the movement of nodes. Apart from saving the power considerably, it also improves the signal strength

  4. Adaptive antenna selection and Tx/Rx beamforming for large-scale MIMO systems in 60 GHz channels

    Prasad Narayan


    Full Text Available Abstract We consider a large-scale MIMO system operating in the 60 GHz band employing beamforming for high-speed data transmission. We assume that the number of RF chains is smaller than the number of antennas, which motivates the use of antenna selection to exploit the beamforming gain afforded by the large-scale antenna array. However, the system constraint that at the receiver, only a linear combination of the receive antenna outputs is available, which together with the large dimension of the MIMO system makes it challenging to devise an efficient antenna selection algorithm. By exploiting the strong line-of-sight property of the 60 GHz channels, we propose an iterative antenna selection algorithm based on discrete stochastic approximation that can quickly lock onto a near-optimal antenna subset. Moreover, given a selected antenna subset, we propose an adaptive transmit and receive beamforming algorithm based on the stochastic gradient method that makes use of a low-rate feedback channel to inform the transmitter about the selected beams. Simulation results show that both the proposed antenna selection and the adaptive beamforming techniques exhibit fast convergence and near-optimal performance.

  5. A Novel Adaptive MAC Protocol for Wireless Internet Access Network with Smart Antennas

    YANGJun; LIJiandong


    Employing smart antennas in the Central access point (CAP) of wireless Internet access networks is studied. Based on the characteristics of the networks and smart antennas, a Polling-based Adaptive beamforming multiple access protocol (PB-ABFMA) is proposed. In PB-ABFMA, the CAP requests the corresponding Mobile terminal (MT) to transmit training sequence just before the data packets transmission, so the Temporal reference beamforming (TRB) can be performed by the smart antennas. The CAP schedules packet transmissions based on the polling mechanism and dynamic TDMA, and a mini-slot is used to keep connectivity when an MT is idle, therefore,the access delay is reduced. Meanwhile, a simple and effec-tive access method is proposed to guarantee rapid access of new arrival MTs to the channel. Based on the “requestreply” traffic, which is the main traffic in Internet, the theoretical analysis of channel utilization and mean turnaround delay is presented. Analysis and simulation results show that the proposed PB-ABFMA protocols effectively support the application of smart antennas and provide high channel utilization and low turn-around delay.



    In wireless communication environment, the time-varying channel and angular spreads caused by multipath fading and the mobility of Mobile Stations (MS) degrade the performance of the conventional Direction-Of-Arrival (DOA) tracking algorithms. On the other hand, although the DOA estimation methods based on the Maximum Likelihood (ML) principle have higher resolution than the beamforming and the subspace based methods, prohibitively heavy computation limits their practical applications. This letter first proposes a new suboptimal DOA estimation algorithm that combines the advantages of the lower complexity of subspace algorithm and the high accuracy of ML based algorithms, and then proposes a Kalman filtering based tracking algorithm to model the dynamic property of directional changes for mobile terminals in such a way that the association between the estimates made at different time points is maintained. At each stage during tracking process, the current suboptimal estimates of DOA are treated as measurements, predicted and updated via a Kalman state equation, hence adaptive tracking of moving MS can be carried out without the need to perform unduly heavy computations. Computer simulation results show that this proposed algorithm has better performance of DOA estimation and tracking of MS than the conventional ML or subspace based algorithms in terms of accuracy and robustness.

  7. Pattern Synthesis of Planar Nonuniform Circular Antenna Arrays Using a Chaotic Adaptive Invasive Weed Optimization Algorithm

    Huaning Wu


    Full Text Available A novel invasive weed optimization (IWO variant called chaotic adaptive invasive weed optimization (CAIWO is proposed and applied for the optimization of nonuniform circular antenna arrays. A chaotic search method has been combined into the modified IWO with adaptive dispersion, where the seeds produced by a weed are dispersed in the search space with standard deviation specified by the fitness value of the weed. To evaluate the performance of CAIWO, several representative benchmark functions are minimized using various optimization algorithms. Numerical results demonstrate that the proposed approach improves the performance of the algorithm significantly, in terms of both the convergence speed and exploration ability. Moreover, the scheme of CAIWO is employed to find out an optimal set of weights and antenna element separation to obtain a radiation pattern with maximum side-lobe level (SLL reduction with different numbers of antenna element under two cases with different purposes. The design results obtained by CAIWO have comfortably outperformed the published results obtained by other state-of-the-art metaheuristics in a statistically meaningful way.

  8. Adaptive automat for compensating antenna gain losses in a model of equipment for tropospheric-scatter radio communications

    Rudakov, V. I.


    This study deals with the problem of adaptive simultaneous compensation of antenna gain losses and quick and slow fadings of signal in a sample of equipment for tropospheric-scatter radio communications using an adaptive automat that ensures automatic equality of these two values and the specified information reliability.

  9. Instantaneous Attitude Determination Based on Original Multi-antenna Observations Using Adaptively Robust Kalman Filtering

    GAN Yu


    Full Text Available Attitude determination directly by carrier phase observation makes optimal use of observation and attitude constraints. The phase models based on misalignment angle and multiplicative quaternion error are derived. The state models for attitude estimation with and without external angular rate sensors are both erected. The attitude errors are estimated by adaptively robust filtering, in which the adaptive factors of ambiguity and attitude error are decided respectively following the idea of multi adaptive factor filtering. The factor of attitude is determined by a three-section function containing Ratio. Adaptively robust filtering makes the best use of constraint and historical information, fusing them in the calculation of float solution. As the accuracy of float solution and the structure of covariance matrix are improved greatly, the fix solution can be searched efficiently using LAMBDA (least-squares ambiguity decorrelation adjustment method merely, perfectly fulfilling the real-time requirement. Field test of a ship-based three-antenna attitude system is used to validate the proposed method. It is showed that direct attitude determination based on adaptively robust filtering has obvious advantages in efficiency and reliability.

  10. Design of a Demonstrator of an Adaptive steerable Antenna system for removal of Interference, clutter, Jammer based on AWG &VSA

    M Chakraborty


    Full Text Available Interfering, clutter and jamming systems are becoming an increasing concern to the military and security industries worldwide. To overcome these problems phase array antennas and adaptive beam forming systems offers a potential solution. STAP is an application of optimum and adaptive array processing algorithms to the radar problem of target detection in ground clutter and interference with pulse-Doppler waveforms.In this paper we have presented our work of designing a MVDR beam former receiver using AWG and VSA. The minimumvariance distortion less response (MVDR approach is very popular technic in array processing that generates some mean square error or values. When these values fed to the phase array antenna system results in electronic steering of antenna beam according to the weight vector generated.

  11. A performance analysis of multi-hop ad hoc networks with adaptive antenna array systems

    Ali, Olfa Ben Sik; Gagnon, Francois


    Based on a stochastic geometry framework, we establish an analysis of the multi-hop spatial reuse aloha protocol (MSR-Aloha) in ad hoc networks. We compare MSR-Aloha to a simple routing strategy, where a node selects the next relay of the treated packet as to be its nearest receiver with a forward progress toward the final destination (NFP). In addition, performance gains achieved by employing adaptive antenna array systems are quantified in this paper. We derive a tight upper bound on the spatial density of progress of MSR-Aloha. Our analytical results demonstrate that the spatial density of progress scales as the square root of the density of users, and the optimal contention density (that maximizes the spatial density of progress) is independent of the density of users. These two facts are consistent with the observations of Baccelli et al., established through an analytical lower bound and through simulations.

  12. Space-borne antenna adaptive anti-jamming method based on gradient-genetic algorithm


    A novel space-borne antenna adaptive anti-jamming method based on the genetic algorithm(GA), which is combined with gradient-like reproduction operators is presented,to search for the best weight for pattern synthesis in radio frequency(RF).Combined,the GA's the capability of the whole searching is,but not limited by selection of the initial parameter,with the gradient algorithm's advantage of fast searching.The proposed method requires a smaller sized initial population and lower computational complexity.Therefore,it is flexible to implement this method in the real-time systems.By using the proposed algorithm,the designer can efficiently control both main-lobe shaping and side-lobe level.Simulation results based on the spot survey data show that the algorithm proposed is efficient and feasible.

  13. Computationally Efficient Blind Code Synchronization for Asynchronous DS-CDMA Systems with Adaptive Antenna Arrays

    Chia-Chang Hu


    Full Text Available A novel space-time adaptive near-far robust code-synchronization array detector for asynchronous DS-CDMA systems is developed in this paper. There are the same basic requirements that are needed by the conventional matched filter of an asynchronous DS-CDMA system. For the real-time applicability, a computationally efficient architecture of the proposed detector is developed that is based on the concept of the multistage Wiener filter (MWF of Goldstein and Reed. This multistage technique results in a self-synchronizing detection criterion that requires no inversion or eigendecomposition of a covariance matrix. As a consequence, this detector achieves a complexity that is only a linear function of the size of antenna array (J, the rank of the MWF (M, the system processing gain (N, and the number of samples in a chip interval (S, that is, 𝒪(JMNS. The complexity of the equivalent detector based on the minimum mean-squared error (MMSE or the subspace-based eigenstructure analysis is a function of 𝒪((JNS3. Moreover, this multistage scheme provides a rapid adaptive convergence under limited observation-data support. Simulations are conducted to evaluate the performance and convergence behavior of the proposed detector with the size of the J-element antenna array, the amount of the L-sample support, and the rank of the M-stage MWF. The performance advantage of the proposed detector over other DS-CDMA detectors is investigated as well.

  14. Improved performance of a hybrid radio/fiber system using a directly modulated laser transmitter with external injection

    Kaszubowska-Anandarajah, Aleksandra; Anandarajah, Prince M.; Barry, Liam P.


    A directly modulated laser diode with external light injection is used to generate microwave optical signals for a hybrid radio/fiber system. The external light injection greatly enhances the frequency response of the laser, and thus, significantly improves the overall performance of the hybrid system. Experimental results show a 14-dB improvement in system performance for the externally injected laser in a hybrid radio/fiber communication link used for distributing 155-Mb/s data signals

  15. Reconfigurable antennas

    Bernhard, Jennifer


    This lecture explores the emerging area of reconfigurable antennas from basic concepts that provide insight into fundamental design approaches to advanced techniques and examples that offer important new capabilities for next-generation applications. Antennas are necessary and critical components of communication and radar systems, but sometimes their inability to adjust to new operating scenarios can limit system performance. Making antennas reconfigurable so that their behavior can adapt with changing system requirements or environmental conditions can ameliorate or eliminate these restricti

  16. Designing Adaptive Linear Array Antenna to Achieve Pattern Steering Optimization by Phase-Amplitude Perturbations Using Genetic Algorithms

    HSUChaohsing; CHENTsongyi; PanJengshyang


    In this paper, a phase-amplitude perturbation method of an adaptive array factor based on the genetic algorithm is proposed. The design for an optimal beam pattern of an adaptive antenna is able to not only suppress interference by placing nulls at the directions of the interfering sources but also provide a maximized main lobe in the direction of the desired signal, i.e., to maximizethe Signal interference ratio (SIR). In order to achieve this goal, a kind of new convergent skill called the two-way convergent method for genetic algorithms is proposed. The phase-amplitude perturbation method is applied to realize the optimal beam pattern of an adaptively linear array antenna. The Genetic algorithms are applied to find the optimal phase-amplitude weighting vector of adaptive array factor. An optimal beam pattern of linear array is derived by phase-amplitude perturbations using a genetic algorithm. Computer simulation result is given to demonstrate the effectiveness of the proposed method.

  17. Precise Calibration of a GNSS Antenna Array for Adaptive Beamforming Applications

    Saeed Daneshmand


    Full Text Available The use of global navigation satellite system (GNSS antenna arrays for applications such as interference counter-measure, attitude determination and signal-to-noise ratio (SNR enhancement is attracting significant attention. However, precise antenna array calibration remains a major challenge. This paper proposes a new method for calibrating a GNSS antenna array using live signals and an inertial measurement unit (IMU. Moreover, a second method that employs the calibration results for the estimation of steering vectors is also proposed. These two methods are applied to the receiver in two modes, namely calibration and operation. In the calibration mode, a two-stage optimization for precise calibration is used; in the first stage, constant uncertainties are estimated while in the second stage, the dependency of each antenna element gain and phase patterns to the received signal direction of arrival (DOA is considered for refined calibration. In the operation mode, a low-complexity iterative and fast-converging method is applied to estimate the satellite signal steering vectors using the calibration results. This makes the technique suitable for real-time applications employing a precisely calibrated antenna array. The proposed calibration method is applied to GPS signals to verify its applicability and assess its performance. Furthermore, the data set is used to evaluate the proposed iterative method in the receiver operation mode for two different applications, namely attitude determination and SNR enhancement.


    Amor Smida


    Full Text Available A new and very speedy synthesis method for linear array antennas with periodic element spacing is described. This study presents an efficient method for the pattern synthesis based on Taguchi’s method. A number of representative examples are presented to demonstrate the various unique capabilities of the method. A set of phase shift weights are generated in order to steer the beam towards any desired direction and avoiding interference. For isotropic linear antenna arrays parameter. The fitness function that allows the calculations of the phase shift weights is presented. The results of Taguchi’s method are validated by using rectangular patch antenna and simulated by software CST2009 (CST microwave studio. Taguchi’s method is briefly described in part 2. In part 3 the formulation of the array factor for linear arrays is given and fitness function will be mentioned. The numerical results optimized by Taguchi’s method are given in part 4. The last results are discuss and validated by using rectangular patch antenna and simulated by software CST2009 (CST microwave studio in part 5. Finally, part 6 makes conclusions.

  19. Link adaptation strategies for multi-antenna assisted WiMAX-like system

    Rahman, Muhammad Imadur; Das, Suvra Sekhar; Wang, Yuanye;


    that, if we cannot find the exact Signal to Noise Ratio (SNR) thresholds due to different reasons, such as reduced Link Adaptation (LA) rate, Channel State Information (CSI) error, feedback delay etc., it is better to fix the transmit power across all sub-channels to guarantee the target Frame Error...

  20. Adaptive antenna selection and Tx/Rx beamforming for large-scale MIMO systems in 60 GHz channels

    Prasad Narayan; Wang Xiaodong; Dong Ke; Zhu Shihua


    Abstract We consider a large-scale MIMO system operating in the 60 GHz band employing beamforming for high-speed data transmission. We assume that the number of RF chains is smaller than the number of antennas, which motivates the use of antenna selection to exploit the beamforming gain afforded by the large-scale antenna array. However, the system constraint that at the receiver, only a linear combination of the receive antenna outputs is available, which together with the large dimension of...

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

    Radaydeh, Redha Mahmoud


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

  2. Antennas - Our electronic eyes and ears

    Kraus, John D.


    Although the number of antenna types is vast, all antenna properties may be characterized in terms of the same basic parameters of radiation pattern, impedance, radar cross-section, and temperature. A comprehensive introduction is presented to antenna configurations; these encompass, among antennas constructed of wire or tubing, such wideband and circularly polarized types as helices, linear conductors, and loops. Sheet-conductor antenna families include reflectors, waveguides, and slotted antennas. Nonconducting dielectric antennas are lenses, polyrods, and slabs. Antenna array types range over 'driven', parasitic, and adaptive configurations. 'Two half-wavelength' and 'four half-wavelength' element arrays are also discussed.

  3. Radar techniques using array antennas

    Wirth, Wulf-Dieter


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

  4. Wireless Distributed Antenna MIMO


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

  5. Plasma antennas

    Anderson, Theodore


    The plasma antenna is an emerging technology that partially or fully utilizes ionized gas as the conducting medium instead of metal to create an antenna. The key advantages of plasma antennas are that they are highly reconfigurable and can be turned on and off. The disadvantage is that the plasma antennas require energy to be ionized. This unique resource provides you with a solid understanding of the efficient design and prototype development of plasma antennas, helping you to meet the challenge of reducing the power required to ionize the gas at various plasma densities. You also find thorou

  6. Improved High-Rejection Filters and MEMS-Enabled Smart Reconfigurable Antennas Project

    National Aeronautics and Space Administration — Proposed work envisions development of high-rejection filters and smart reconfigurable antennas using MEMS switches. Adaptive feature of the proposed antenna...

  7. Reconfigurable antenna pattern verification

    Drexler, Jerome P. (Inventor); Becker, Robert C. (Inventor); Meyers, David W. (Inventor); Muldoon, Kelly P. (Inventor)


    A method of verifying programmable antenna configurations is disclosed. The method comprises selecting a desired antenna configuration from a plurality of antenna configuration patterns, with the selected antenna configuration forming at least one reconfigurable antenna from reconfigurable antenna array elements. The method validates the formation of the selected antenna configuration to determine antenna performance of the at least one reconfigurable antenna.

  8. Smart Antenna for Cellular Mobile Communication

    Jain, R K; Agrawal, N K


    The adoption of smart / adaptive antenna techniques in future wireless systems is expected to have a significant impact on the efficient use of the spectrum, the minimization of the cost of establishing new wireless networks, the optimization of service quality and realization of transparent operation across multi technology wireless networks [1]. This paper presents brief account on smart antenna (SA) system. SAs can place nulls in the direction of interferers via adaptive updating of weights linked to each antenna element. SAs thus cancel out most of the co-channel interference resulting in better quality of reception and lower dropped calls. SAs can also track the user within a cell via direction of arrival algorithms [2]. This paper explains the architecture, evolution and how the smart / adaptive antenna differs from the basic format of antenna. The paper further explains about the radiation pattern of the antenna and why it is highly preferred in its relative field. The capabilities of smart / adaptive ...

  9. Microstrip Antenna

    Anuj Mehta


    Abstract This article presents an overview of the microstrip patch antenna and its design techniques. Basically a microstrip patch antenna comprises of a trace of copper or any other metal of any geometry on one side of a standard printed circuit board substrate with other side grounded. The antenna is fed using various feeding techniques like coaxial strip line aperture coupling or proximity coupling techniques. The working principle and the radiation mechanism have also been described. The ...

  10. Circularly polarized antennas

    Gao, Steven; Zhu, Fuguo


    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

  11. Antenna reconfiguration using metasurfaces

    Zhu, H; Cheung, WSW; Yuk, TI


    The paper describes the designs of a frequency-reconfigurable, polarization reconfigurable and pattern reconfigurable antennas using metasurfaces (MS). The frequency-reconfigurable and polarization reconfigurable antennas are composed of a simple circular patch antenna or slot antenna as the source antenna and a circular MS with the same diameter, with both source antenna and MS implemented using planar technology. The pattern reconfigurable antenna is composed of a circular patch antenna as ...

  12. Diamond dipole active antenna

    Bubnov, I. N.; Falkovych, I. S.; Gridin, A. A.; Stanislavsky, A. A.; Reznik, A. P.


    Advantages of the diamond dipole antenna as an active antenna are presented. Such an antenna is like an inverted bow-tie antenna, but the former has some advantages over the ordinary bow-tie antenna. It is shown that the diamond dipole antenna may be an effective element of a new antenna array for low-frequency radio astronomy as well as a communication antenna.


    陶云刚; Tobias; Melz


    The modern information society continuously demands for larger communication capacities.These demands can be met by developing higher telecommunication frequencies.With this goal and modern communication technology basing on satellite systems with reflector antennas,a new structural design concept of a satellite antenna reflector as an adaptive structural system is being developed.In this article the manufacturing of such a parabolic central focus sandwich reflector of a diameter of 900mm with intermediate modulus carbon fibre/epoxy face sheets and aluminium honeycomb core with integrated actuators will be introduced.The fabrication of the actuator packages,the filament winding process and the assembly of the actuators will be presented.With this paper the authors intend to introduce this new design concept as a promising technique to realise lightweight,by means of active control thermally highly stable and economic reflector structures for future communicaiton applications.%现代信息社会越来越需要更大的通讯能力,这种需要可通过发展更高的远程通讯频率来满足,为实现此目的,使用发射天线的卫星通讯系统。德国宇航研究院结构力学研究所正在研制一种新的、用于卫星天线发射器的自适应结构体系。本文介绍了一种直径为900毫米的抛物面型叠层发射器的制造工艺。该卫星天线发射器叠层材料为中等弹性模量的碳纤维--环氧树脂面板和带有集成激励控制驱动器的铝蜂窝夹芯。并将给出驱动器封装的制造,纤维缠绕过程和驱动器的装配方法。本文介绍了这一新的设计思想和具有高效控制,高热稳定性及经济的、重量轻的自适应智能天线反射器结构。

  14. Adapt

    Bargatze, L. F.


    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  15. UWB planar antenna technology


    Recent developments of the ultra-wideband(UWB)planar antennas are reviewed,where the progress in UWB plate monopole antennas,UWB printed monopole antennas and the UWB printed slot antennas is introduced and compared.In addition,the UWB printed antennas with the band-notched functions are also presented.

  16. Astigmatism in reflector antennas.

    Cogdell, J. R.; Davis, J. H.


    Astigmatic phase error in large parabolic reflector antennas is discussed. A procedure for focusing an antenna and diagnosing the presence and degree of astigmatism is described. Theoretical analysis is conducted to determine the nature of this error in such antennas.

  17. A directive pulse antenna

    Titov, A.N.; Titov, A. A.


    Using quite general concepts as guidance in the design of an antenna for short pulse transmission and reception, a new type of horn-antenna has been devised. A certain variety of experimental data obtained by the antenna are presented.

  18. Optical antennas and plasmonics

    Park, Q-Han


    Optical antenna is a nanoscale miniaturization of radio or microwave antennas that is also governed by the rule of plasmonics. We introduce various types of optical antenna and make an overview of recent developments in optical antenna research. The role of local and surface plasmons in optical antenna is explained through antenna resonance and resonance conditions for specific metal structures are explicitly obtained. Strong electric field is shown to exist within a highly localized region o...


    V. Jebaraj


    Full Text Available Slot antennas are often used at UHF and microwave frequencies. In slot antenna for RFID reader applications the frequency ranges from 902-923MHz to achieve circular polarization. The shapes and size of the slot, as well as the driving frequency, determine the radiation distribution pattern. The proposed compact size circularly polarized slotted microstrip antenna are summarized with design rules. The circularly polarized radiation in square patch antenna can be obtained by perturbation technique with different shapes of slot in the orthogonal direction. A single feed configuration based symmetric slotted microstrip antenna is adapted to realize the compact circularly polarized microstrip antennas. Based on the perimeter, the size of the slot on microstrip slot antenna are studied and compared. The Operating frequency of the antenna is 912MHz that can be tuned by varying the perimeter of the slot while the keeping the circularly polarized radiation unchanged. The schematic and layout are configured by using Advanced Design System (ADS. Return loss, Resonant Frequency, Axial Ratio (AR, and Gain were determined for the proposed system using ADS. A measured 3dB Axial Ratio (AR bandwidth around 6MHz with 16MHz impedance bandwidth has been achieved for the antenna on a RO3004C substrate with dielectric constant 3.38.

  20. Antennas in inhomogeneous media

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


    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

  1. Terminal Antenna Design

    Skrivervik, A. K.; Zurcher, J. F.


    This paper introduces first some general considerations about antenna miniaturization and multi-band terminal antenna design. These general design principles are then illustrated on some practical applications.

  2. A True Metasurface Antenna

    Mohamed El Badawe; Almoneef, Thamer S.; Omar M. Ramahi


    We present a true metasurface antenna based on electrically-small resonators. The resonators are placed on a flat surface and connected to one feed point using corporate feed. Unlike conventional array antennas where the distance between adjacent antennas is half wavelength to reduce mutual coupling between adjacent antennas, here the distance between the radiating elements is electrically very small to affect good impedance matching of each resonator to its feed. A metasurface antenna measur...

  3. Antenna systems research

    Keen, Keith Malcolm


    This thesis is an overview of a number of investigations on antenna systems and related subjects over a period of 28 years, which has resulted in 44 publications in the technical literature, one current patent, and an M.Sc. thesis. The investigations have been grouped into 7 categories: - Log periodic antennas, - Antenna performance measurement techniques, - Spacecraft Antenna Systems, - Satcom Terminal Antennas, - Transmission lines and baluns, - High Radar Cross Secti...

  4. Plasma antennas: dynamically configurable antennas for communications

    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

  5. Adaptive antenna system for OFDMA WiMAX radio-over-fiber links using a directly modulated R-SOA and optical filtering

    Presi, Marco; Prince, Kamau; Chiuchiarelli, Andrea;


    We implement an adaptive beam steering system based on a directly-modulated unseeded reflective SOA. this system allows the distribution of 2.4 GHz 64-QAM OFDMA signals with 2048-subcarriers (72 Mb/s) satisfying the IEEE 802.16e specifications......We implement an adaptive beam steering system based on a directly-modulated unseeded reflective SOA. this system allows the distribution of 2.4 GHz 64-QAM OFDMA signals with 2048-subcarriers (72 Mb/s) satisfying the IEEE 802.16e specifications...

  6. A Case Study on Distributed Antenna Systems

    Sørensen, Troels Bundgaard


    assignment is described in terms of algorithms for power allocation and access port assignment, as well as algorithms for (dynamic) channel assignment. After an outline of simulation assumptions, system capacity comparisons are given between the adaptive DAS and a system with fixed channel and access port......Passive distributed antenna systems (DASs) consisting of distributed feeder lines or single point antennas are now often installed in large office buildings where they provide efficient coverage throughout the building. More sophisticated DASs with intelligent reuse and the ability to adapt to...

  7. Adaptive antenna system for OFDMA WiMAX radio-over-fiber links using a directly modulated R-SOA and optical filtering

    Presi, Marco; Prince, Kamau; Chiuchiarelli, Andrea; Cerutti, Isabella; Constabile, Giampiero; Tafur Monroy, Idelfonso; Ciaramella, Ernesto

    We implement an adaptive beam steering system based on a directly-modulated unseeded reflective SOA. this system allows the distribution of 2.4 GHz 64-QAM OFDMA signals with 2048-subcarriers (72 Mb/s) satisfying the IEEE 802.16e specifications...

  8. The spherical helical antenna

    Cardoso, J. Christopher


    The spherical helical antenna is investigated as a new variation of the conventional helical antenna. The spherical helix is a wire antenna in a helix shape that is wound over a spherical surface instead of the standard cylindrical one. Analysis of this structure requires numerical methods and experimental measurements because its complex geometry makes it very difficult to develop analytic expressions for its radiation characteristics. The wire antenna code ESP, based on the method of ...

  9. Space-Frame Antenna

    Curtis, Steven A.


    The space-frame antenna is a conceptual antenna structure that would be lightweight, deployable from compact stowage, and capable of deforming itself to a size, shape, and orientation required for a specific use. The space-frame antenna would be a trusslike structure consisting mostly of a tetrahedral mesh of nodes connected by variable-length struts. The deformation of the antenna to a desired size, shape, and orientation would be effected through coordinated lengthening and shorting of the struts.

  10. Wide Coverage Antennas

    Zackrisson, Jan


    Small satellites require small and lightweight antennas for telemetry and command function as well as for downlinking of data. We have during the last thirty years developed a large suite of wide coverage antennas. The basic radiator designs used are quadrifilar helices, waveguides, horns and patch excited cups (PEC) depending on frequency range, coverage requirements and application. The antenna designs range from L-band up to Ka-band frequencies. Typical coverages for the antennas are from ...

  11. A New Joint Antenna Selection Algorithm Based on Capacity

    Li Yuan


    Full Text Available Antenna Selection in MIMO systems can increase the system capacity, reduce the MIMO system complexity and cost of radio links effectively. In this paper, a new joint antenna selection algorithm was presented which can adaptively change the number of the selected transmitting and receiving antenna number according to the channel station. It can obtain the similar system capacity with the optimal joint antenna selection algorithm in any correlation coefficient, but the calculated amount is far less than the optimal joint algorithm.



    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...

  13. The mathematical model of antenna and antenna-radome system

    Knyazeva, L. V.; Artishev, A. I.


    Methods, algorithms and programs for calculation by computer of the characteristics of the antenna and the antenna-radome system (ARS) are developed. The type of antenna considered is the phased antenna array (PAA) or the cophase antenna with a mechanical beam control (an antenna array - AA). Radome shape is spherical, quasi-conic or flattened ellipsoid. Radome shell is multilayer ( N≥1), same-thickness, or special profile. Errors in the manufacture of the antenna are taken into account. Prog...

  14. A True Metasurface Antenna

    Badawe, Mohamed El; Almoneef, Thamer S.; Ramahi, Omar M.


    We present a true metasurface antenna based on electrically-small resonators. The resonators are placed on a flat surface and connected to one feed point using corporate feed. Unlike conventional array antennas where the distance between adjacent antennas is half wavelength to reduce mutual coupling between adjacent antennas, here the distance between the radiating elements is electrically very small to affect good impedance matching of each resonator to its feed. A metasurface antenna measuring 1.2λ × 1.2λ and designed to operate at 3 GHz achieved a gain of 12 dBi. A prototype was fabricated and tested showing good agreement between numerical simulations and experimental results. Through numerical simulation, we show that the metasurface antenna has the ability to provide beam steering by phasing all the resonators appropriately.

  15. 2D Active Antenna Array Design for FD-MIMO System and Antenna Virtualization Techniques

    Ioannis Tzanidis


    Full Text Available Full dimension MIMO (FD-MIMO is one of the key technologies presently studied in the 3GPP for the next generation long-term evolution advanced (LTE-A systems. By incorporating FD-MIMO into LTE/LTE-A systems, it is expected that system throughput will be drastically improved beyond what is possible in conventional LTE systems. This paper presets details on the 2D active antenna array design for FD-MIMO systems supporting 32 antenna elements. The FD-MIMO system allows for dynamic and adaptive precoding to be performed jointly across all antennas thus achieving more directional transmissions in the azimuth and elevation domains simultaneously, to a larger number of users. Finally, we discuss 2D antenna array port virtualization techniques for creating beams with wide coverage, necessary for broadcasting signals to all users within a sector, such as the CRS (Common Reference Signal.

  16. Secondary Surveillance Radar Antenna

    Schejbal, Vladimír; Bezoušek, Pavel; Pidanič, Jan; Chyba, Milan


    This paper deals with a secondary surveillance radar (SSR) array antenna, which is intended for a system combining the secondary surveillance radar antenna and the primary surveillance radar antenna. It describes the patch array elements and the synthesis for the secondary surveillance radar array, considering both elevation and azimuth patterns for sum, difference, and sidelobe-suppression beams, and suspended stripline couplers. The utilization of multilayer techniques allows the connection...

  17. Antenna Structure Registration (ASR)

    Federal Communications Commission — As part of its ongoing efforts to promote air safety, the Federal Communications Commission requires owners to register certain antenna structures (generally those...

  18. Cellular Reflectarray Antenna

    Romanofsky, Robert R.


    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.

  19. A curl antenna

    Nakano, Hisamatsu; Okuzawa, Shigeru; Ohishi, Katsumi; Mimaki, Hiroaki; Yamauchi, Junji


    A radiation element, designated as a curl antenna, is proposed for a circularly polarized antenna. The radiation characteristics of the curl are numerically analyzed. The gain is approximately 8.4 dB, and the 3-dB axial ratio criterion is 6.7%. Two aspects of curl array antennas are also presented: a decoupling factor between two curls and a circular array antenna consisting of 168 curls. Calculations show how the decoupling factor depends on the relative rotation angle of the two curls. The ...

  20. Cavity Backed Slot Antenna

    Sarang Masani, Ila Parmar, Hitendra Jadeja


    Full Text Available Among the current driving forces in wireless communications, there is a need for compact, efficient, inexpensive and reproducible antennas. In some instances, particularly long-distance applications, radiators with directive, high-gain characteristics are necessary. This paper proposes a cavity-backed slot antenna to that end. This antenna will enhance the gain, directivity and can also be easily flush mounted to the flying object. The shape and size of the slot can be effectively utilized to get the desired result. The proposed antenna is feed by waveguide which facilitate it to be applicable at high power operation where coaxial cable fails due to skin effect. Present antenna is verified using Numerical Technique called Finite Element Method FEM. The conception of this antenna is realized by the software HFSS “Ansoft-High Frequency Structure Simulator”. By properly selecting shapes, dimensions of the slots and number of slot affects the parameters like return loss, gain along Θ, Ø directions, Cartesian plot and radiation pattern .The Backing of cavity to the slot antenna provide the basics of the gain enhancement and the slot loading effect and the cavity volume plays an important role in achieving the desired return loss at the specific frequency.The simulated antenna shows the 7.0944 db of gain and return loss of -28.60. The proposed antenna works at 6 GHz.


    Rhode Island State Dept. of Education, Providence.


  2. Directional borehole antenna - Theory

    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)

  3. Substrate integrated antennas and arrays

    Cheng, Yu Jian


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

  4. Integrated solar panel antennas

    Vaccaro, S.; P. TORRES; Mosig, J. R.; Shah, Arvind; Zürcher,, J.-F.; A. K. Skrivervik; Gardiol, F.; de Maagt, P.; Gerlach, L.


    A new antenna which combines solar cells and printed patches is presented. The antenna is designed so as to accommodate the solar cells that provide power to an MMIC amplifier. A 2×4 array is presented, which operates at the frequency of 3.76 GHz and has a bandwidth of 16% and gain up to 30 dBi (active).

  5. Entropy and Fractal Antennas

    Emanuel Guariglia


    The entropies of Shannon, Rényi and Kolmogorov are analyzed and compared together with their main properties. The entropy of some particular antennas with a pre-fractal shape, also called fractal antennas, is studied. In particular, their entropy is linked with the fractal geometrical shape and the physical performance.

  6. Annular Planar Monopole Antennas

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


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

  7. Printed Triband Terminal Antenna

    JOHN, MATTHIAS; Ammann, Max; Farrell, R.


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

  8. Sidelobe Canceling for Optimization of Reconfigurable Holographic Metamaterial Antenna

    Johnson, Mikala C; Kutz, J Nathan; Kundtz, Nathan B


    Accurate and efficient methods for beam-steering of holographic metamaterial antennas is of critical importance for enabling consumer usage of satellite data capacities. We develop an optimization algorithm capable of performing adaptive, real-time control of antenna patterns while operating in dynamic environments. Our method provides a first analysis of the antenna pattern optimization problem in the context of metamaterials and for the purpose of directing the central beam and significantly suppressing sidelobe levels. The efficacy of the algorithm is demonstrated both on a computational model of the antenna and experimentally. Due to their exceptional portability, low-power consumption and lack of moving parts, metamaterial antennas are an attractive and viable technology when combined with proven software engineering strategies to optimize performance.

  9. RF MEMS Based Reconfigurable Antennas

    Simons, Rainee N.


    The presentation will first of all address the advantages of RF MEMS circuit in antenna applications and also the need for electronically reconfigurable antennas. Next, discuss some of the recent examples of RF MEMS based reconfigurable microstrip antennas. Finally, conclude the talk with a summary of MEMS antenna performance.

  10. Smart antennas in aerospace applications

    Verpoorte, Jaco; Schippers, Harmen; Roeloffzen, Chris G.H.; Marpaung, David A.I.


    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 electronic compensation techniques.

  11. Vector potential analysis of the helicon antenna in vacuum

    Johnson, Robert W


    The helicon antenna is a well-known device in the field of electric propulsion. Here we investigate the vector potential produced in vacuum by such an antenna with typical size parameters. Both a static and a dynamic analysis are performed. The dynamic calculation is evaluated at both the usual operating frequency and one which is slightly greater. At the higher frequency, a pulse of electromagnetic energy is found to propagate along the cylindrical axis in either direction. The possible adaptation of the helicon antenna as a RF injection device for burning plasma is discussed.

  12. Contactless Measurement of Angular Velocity using Circularly Polarized Antennas

    Sipal, Vit; Narbudowicz, Adam; Ammann, Max


    An innovative method to measure the angular velocity using circularly polarized antennas is proposed. Due to the properties of circular polarization, the angular velocity is frequency modulated (FM) on a wireless carrier. This enables a low-cost precise continuous measurement of angular velocity using a standard FM demodulator. The hardware can be easily adapted for both high and low angular velocity values. The precise alignment angle between the antennas can be determined if the initial ant...

  13. Selective Cooperative Transmission in Ad Hoc Networks with Directional Antennas

    Eui-Jik Kim; Sungkwan Youm


    This paper presents a selective cooperative transmission scheme (abbreviated SCT) for ad hoc network with directional antennas that leverages the benefits of directional-only antenna approach and cooperative communication. The main feature of SCT is its adaptability to the channel condition in the network. In other words, when the node sends data, SCT determines its transmission strategy on either direct or cooperative transmission via a relay node called a forwarder, depending on the transmi...

  14. Field-aligned ICRF antenna design for EAST

    Wukitch, S. J.; Lin, Y.; Qin, C.; Zhang, X.; Beck, W.; Koert, P.; Zhou, L.


    For ion cyclotron range of frequency (ICRF), a number of physics and technological challenges remain for steady state, toroidal devices. Among the most critical is maintaining good coupling and maximizing the coupled power through plasma variations including edge localized modes (ELMs) and confinement transitions. As pulse length increases, enhanced localized heat loads associated with antenna operation can challenge antenna integrity. In addition, ICRF impurity sources and contamination need to be minimized to enable effective plasma heating. Here, we report on a four strap field aligned (FA) antenna design for the EAST tokamak. A FA antenna is an antenna where the current straps and antenna side enclosure are perpendicular to the total magnetic field while the Faraday screen rods are parallel to the total magnetic field. In C-Mod, a FA antenna has been shown to be inherently load tolerant which allows for robust power delivery to the plasma. Furthermore, the RF enhanced heat flux and antenna impurity source were nearly eliminated. For both L and H-mode discharges, the core impurity contamination is 20-30% lower but not eliminated. The emerging physics understanding is that the local RF impurity sources and RF enhanced heat flux is reduced due to the geometric alignment of the FA antenna while impurity contamination is a result of far field sheaths. An important aspect of antenna design is to identify a core absorption scenario that is characterized by strong single pass absorption for a broad range of target discharges. To maximize power coupling, the antenna spectrum needs to balance the k|| needed for strong single pass absorption and high coupling efficiency through evanescent layer. The latest design for a FA four strap adapted to EAST device is balance between geometrical constraints and physics requirements.

  15. Atacama Compact Array Antennas

    Saito, Masao; Inatani, Junji; Nakanishi, Kouichiro; Naoi, Takahiro; Yamada, Masumi; Saito, Hiro; Ikenoue, Bungo; Kato, Yoshihiro; Morita, Kou-ichiro; Mizuno, Norikazu; Iguchi, Satoru


    We report major performance test results of the Atacama Compact Array (ACA) 7-m and 12-m antennas of ALMA (Atacama Large Millimeter/submillimeter Array). The four major performances of the ACA antennas are all-sky pointing (to be not more than 2.0 arcsec), offset pointing (to be < 0.6 arcsec) surface accuracy (< 25(20) micrometer for 12(7)m-antenna), stability of path-length (15 micrometer over 3 min), and high servo capability (6 degrees/s for Azimuth and 3 degrees/s for Elevation). The high...

  16. Optimisation of Microstrip Antenna

    H. El Hamchary


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

  17. Tunable Liquid Dielectric Antenna

    Kamal Raj Singh Rajoriya


    Full Text Available This paper presents on modified the dielectric properties of liquid with varying salinity that was based on monopole structure. Dielectric resonator antennas (DRAs can be made with a wide range of materials and allow many excitation methods [2]. Pure water does not work at high frequency (> 1 GHz but increase in the salinity of water modifies the dielectric properties of water. Here proposed antenna shows that when the salinity increases in form of molar solution, the antenna was tuned at different frequency with increases return loss.

  18. Flexible 16 Antenna Array for Microwave Breast Cancer Detection.

    Bahramiabarghouei, Hadi; Porter, Emily; Santorelli, Adam; Gosselin, Benoit; Popović, Milica; Rusch, Leslie A


    Radar-based microwave imaging has been widely studied for breast cancer detection in recent times. Sensing dielectric property differences of tissues has been studied over a wide frequency band for this application. We design single- and dual-polarization antennas for wireless ultrawideband breast cancer detection systems using an inhomogeneous multilayer model of the human breast. Antennas made from flexible materials are more easily adapted to wearable applications. Miniaturized flexible monopole and spiral antennas on a 50-μm Kapton polyimide are designed, using a high-frequency structure simulator, to be in contact with biological breast tissues. The proposed antennas are designed to operate in a frequency range of 2-4 GHz (with reflection coefficient (S11) below -10 dB). Measurements show that the flexible antennas have good impedance matching when in different positions with different curvature around the breast. Our miniaturized flexible antennas are 20 mm × 20 mm. Furthermore, two flexible conformal 4 × 4 ultrawideband antenna arrays (single and dual polarization), in a format similar to that of a bra, were developed for a radar-based breast cancer detection system. By using a reflector for the arrays, the penetration of the propagated electromagnetic waves from the antennas into the breast can be improved by factors of 3.3 and 2.6, respectively. PMID:26011862

  19. Antennas from theory to practice

    Huang, Yi


    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

  20. Design of New Multiband Slotted PIFA Antennas

    Yamina Belhadef; Noureddine Boukli-Hacene


    In this paper, new configurations of slotted PIFA antennas simulated at different frequencies and which can be integrated in mobile handsets are proposed. The design tool is the HFSS software which uses the finite element method. The insertion of slots with various forms on the radiation element allows the creation of new resonances frequencies. The obtained radio electric results show that the structures are well adapted to the desired resonances frequencies.

  1. Nonlinear plasmonic antennas

    Shakeeb Bin Hasan


    Full Text Available Contrary to traditional optical elements, plasmonic antennas made from nanostructured metals permit the localization of electromagnetic fields on length scales much smaller than the wavelength of light. This results in huge amplitudes for the electromagnetic field close to the antenna being conducive for the observation of nonlinear effects already at moderate pump powers. Thus, these antennas exhibit a promising potential to achieve optical frequency conversion and all-optical control of light at the nano-scale. This opens unprecedented opportunities for ultrafast nonlinear spectroscopy, sensing devices, on-chip optical frequency conversion, nonlinear optical metamaterials, and novel photon sources. Here, we review some of the recent advances in exploiting the potential of plasmonic antennas to realize robust nonlinear applications.

  2. Fractal multiband patch antenna

    Borja, C.; Puente Baliarda, Carles; Romeu Robert, Jordi; Anguera Pros, Jaume


    The multiband behaviour of the Sierpinski patch antenna is described in this paper. Experimental results show that the self similarity properties of the fractal shape are translated into its electromagnetic behaviour. Peer Reviewed

  3. Atacama Compact Array Antennas

    Saito, Masao; Nakanishi, Kouichiro; Naoi, Takahiro; Yamada, Masumi; Saito, Hiro; Ikenoue, Bungo; Kato, Yoshihiro; Morita, Kou-ichiro; Mizuno, Norikazu; Iguchi, Satoru


    We report major performance test results of the Atacama Compact Array (ACA) 7-m and 12-m antennas of ALMA (Atacama Large Millimeter/submillimeter Array). The four major performances of the ACA antennas are all-sky pointing (to be not more than 2.0 arcsec), offset pointing (to be < 0.6 arcsec) surface accuracy (< 25(20) micrometer for 12(7)m-antenna), stability of path-length (15 micrometer over 3 min), and high servo capability (6 degrees/s for Azimuth and 3 degrees/s for Elevation). The high performance of the ACA antenna has been extensively evaluated at the Site Erection Facility area at an altitude of about 2900 meters. Test results of pointing performance, surface performance, and fast motion capability are demonstrated.

  4. Microwave antenna holography

    Rochblatt, David J.; Seidel, Boris L.


    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.

  5. Rotary antenna attenuator

    Dickinson, R. M.; Hardy, J. C.


    Radio frequency attenuator, having negligible insertion loss at minimum attenuation, can be used for making precise antenna gain measurements. It is small in size compared to a rotary-vane attenuator.

  6. Intelsat VI antenna system

    Caulfield, M. F.; Lane, S. O.; Taormina, F. A.

    The antenna system design of a series of five new communications satellites known as Intelsat VI is described in detail. Each satellite will utilize 50 transponders operating in the C and K band portions of the frequency spectrum. The transponders are interconnectible using either static switch matrices or a network which provides satellite switched time division multiple access capability. The antenna coverages, characteristics, and special design features are shown and discussed.

  7. SANTANA- Smart Antenna Terminal Design

    Liu, Ying


    This project is embedded in SANTANA (Smart Antenna Terminal) project. The project goal is to design a Ka-band circularly polarized antenna radiator for the receiver SANTANA system. The research work focuses on two types of circularly polarized antennas: aperture-coupled patch antenna and CPW-fed patch antenna. A two steps design process is used. Firstly, only the antennas and their feed structure are designed and optimized. Secondly, a via-transition to connect to a MMIC layer is added. When ...

  8. Modeling of compact loop antennas

    Baity, F. W.


    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 sub-tuned RDL antennas. Calculations using the model have been compared with measurements on full-scale mock-ups of RDL 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 the Compact Ignition Tokamak (CIT).

  9. Modeling of compact loop antennas

    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

  10. Modeling of compact loop antennas

    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 sub-tuned RDL antennas. Calculations using the model have been compared with measurements on full-scale mock-ups of RDL 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 the Compact Ignition Tokamak

  11. Imaging antenna arrays

    Rutledge, D. B.; Muha, M. S.


    Many millimeter and far-infrared imaging systems are limited in sensitivity and speed because they depend on a single scanned element. Because of recent advances in planar detectors such as Schottky diodes, superconducting tunnel junctions, and microbolometers, an attractive approach to this problem is a planar antenna array with integrated detectors. A planar line antenna array and optical system for imaging has been developed. The significant advances are a 'reverse-microscope' optical configuration and a modified bow-tie antenna design. In the 'reverse-microscope' configuration, a lens is attached to the bottom of the substrate containing the antennas. Imaging is done through the substrate. This configuration eliminates the troublesome effects of substrate surface waves. The substrate lens has only a single refracting surface, making possible a virtually aplanatic system, with little spherical aberration or coma. The array is characterized by an optical transfer function that is easily measured. An array with 19 dB crosstalk levels between adjacent antennas has been tested and it was found that the array captured 50 percent of the available power. This imaging system was diffraction limited.

  12. Technologies and Applications of Microwave Photonic Antennas

    Y. Yashchyshyn; Chizh, A.; Malyshev, S.; Modelski, J


    This paper describes the development of microwave photonic antennas concepts and their applications. The experimental study of the transmitting and receiving photonic antenna are shown. The transmitting photonic antenna consists of photodiode integrated with microstrip E-shaped patch antenna, and receiving photonic antenna consists of laser diode integrated directly with the Vivaldi antenna.

  13. Hemispheric ultra-wideband antenna.

    Brocato, Robert Wesley


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

  14. Dual polarization flat plate antenna

    Kelly, Kenneth C.

    Rectangular waveguides with radiating slots are used in groups to form planar array microwave antennas with large apertures and small depth. Such flat plate antennas are widely used on spacecraft and aircraft. Typically, flat plate antennas provide fixed linear polarization. The present paper describes a new flat plate antenna which produces two coincident beams that are distinguished by their orthogonal linear polarizations. The antenna has two ports, one for each of the coicident beams. Completely external to the antenna, connecting a simple network to those terminal ports enables the antenna to provide right circular polarization from one port and left from the other. A different external network enables the antenna to have arbitrarily adjustable polarizations.

  15. 96-antenna radioheliograph

    Lesovoi, S V; Ivanov, E F; Gubin, A V


    Here we briefly present some design approaches for a multifrequency 96-antenna radioheliograph. The array antenna configuration, transmission lines and digital receivers are the main focus of this work. The radioheliograph is a T-shaped centrally-condensed radiointerferometer operating at the frequency range 4-8~GHz. The justification for the choice of such a configuration is discussed. The antenna signals are transmitted to a workroom by analog optical links. The dynamic range and phase errors of the microwave-over-optical signal are considered. The signals after downconverting are processed by the digital receivers for delay tracking and fringe stopping. The required delay tracking step and data rates are considered. Two 3-bit data streams (I and Q) are transmitted to a correlator with the transceivers embedded in FPGA (Field Programmed Gate Array) chips and with PCI Express cables.

  16. Backfire antennas with dipole elements

    Nielsen, Erik Dragø; Pontoppidan, Knud


    A method is set up for a theoretical investigation of arbitrary backfire antennas based upon dipole structures. The mutual impedance between the dipole elements of the antenna is taken into account, and the field radiated due to a surface wave reflector of finite extent is determined by calculating...... the surface current distribution on the reflector plate. Numerical results obtained for Yagi backfire antennas and short-backfire antennas using this theory are compared with experimental results....

  17. Galileo satellite antenna modeling

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


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

  18. Printed MIMO antenna engineering

    Sharawi, Mohammad S


    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

  19. Antennas fundamentals, design, measurement

    Long, Maurice


    This comprehensive revision (3rd Edition) is a senior undergraduate or first-year graduate level textbook on antenna fundamentals, design, performance analysis, and measurements. In addition to its use as a formal course textbook, the book's pragmatic style and emphasis on the fundamentals make it especially useful to engineering professionals who need to grasp the essence of the subject quickly but without being mired in unnecessary detail. This new edition was prepared for a first year graduate course at Southern Polytechnic State University in Georgia. It provides broad coverage of antenna

  20. The Antennae Galaxies

    Karl, Simon


    The Antennae galaxies (NGC 4038/39) are the nearest and best-studied major merger of two gas-rich spirals in the local Universe. They are named after the characteristic pair of tidal tails that protrude out of their main galactic disks. Due to their proximity the Antennae are extremely well sampled by modern high-resolution observations over an enormous wavelength range, from radio to X-ray. This allows for a comprehensive multiwavelength approach to the present-day morpholo...

  1. DSN Microwave Antenna Holography

    Rochblatt, D. J.; Seidel, B. L.


    The DSN microwave antenna holography project will obtain three-dimensional pictures of the large DSN antenna surfaces. These pictures must be of suffi icient resolution to allow adjustment of the reflector panels to an rms surface of 0.5 mm (0.25 mm, goal). The major parameters and equations needed to define a holographic measurement system are outlined and then the proof of concept demonstration measurement that was made at DSS-43 (Australia) that resulted in contour maps with spatial resolution of 7 m in the aperture plane and resolution orthogonal to the aperture plane of 0.7 mm was discussed.

  2. Hyperbolic thermal antenna

    Barbillon, Grégory; Biehs, Svend-Age; Ben-Abdallah, Philippe


    A thermal antenna is an electromagnetic source which emits in its surrounding, a spatially coherent field in the infrared frequency range. Usually, its emission pattern changes with the wavelength so that the heat flux it radiates is weakly directive. Here, we show that a class of hyperbolic materials, possesses a Brewster angle which is weakly dependent on the wavelength, so that they can radiate like a true thermal antenna with a highly directional heat flux. The realization of these sources could open a new avenue in the field of thermal management in far-field regime.

  3. Antennas on circular cylinders

    Knudsen, H. L.


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

  4. Non-standard antennas

    Le Chevalier, Francois; Staraj, Robert


    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.

  5. Antenna Systems for NUTS

    Marholm, Sigvald


    NTNU is aiming to build and launch a small student satellite compliant with thedouble CubeSat standard, by 2014. The NTNU Test Satellite (NUTS) will carrytwo radio tranceivers and a beacon transmitter, all located in the VHF and UHFamateur bands. The goal of this thesis was to build the whole antenna systems forthe spacecraft.Turnstile antennas were chosen both for UHF and VHF, since they yield thehighest received signal strength on ground throughout the whole pass of the satel-lite. In order...

  6. Square Planar Monopole Antenna

    Ammann, Max


    A planar monopole may be realised by replacing the wire element of a conventional monopole with a planar element. In this case, the planar element which is square, is located above a groundplane and fed using an SMA connector as illustrated. The square monopole has a simple geometry and a smaller bandwidth compared to the circular-disc monopole. However, it is still a broadband antenna with a typical impedance bandwidth of 75 % at S band. This broadband antenna shows a constant radiation patt...

  7. A century of antenna development

    Olver, A. D.

    The paper describes a century of antenna development as part of a century of radio communications. This historical review examines, chronologically, the pre-Hertz period, Hertz antennas, the microwave optics period, the Marconi era, short waves, theoretical design before and after computers, and radar. Consideration is also given to mobile antennas, microwave comunications, radio astronomy, and satellite comunications.

  8. China's Largest Radio Antenna System


    @@ After three-and-half-year efforts, the National Astronomical Observatories at CAS (NAOC) has constructed two arrays of radio antennae: a 50m antenna at Miyun Station in Beijing and a 40m antenna in Kunming, capital of southwest China's Yunnan Province.

  9. Dual Band Microstrip Patch Antenna Using Dual Feed for Wireless Applications

    Vidhi Sharma


    Full Text Available the recent boom in wireless communication industry especially in the area of cellular telephony and wireless data communication has lead to the demand for multiband antennas. Reconfigurable multiband antennas are attractive for many military and commercial applications where it is desirable to have single antenna that can be dynamically reconfigured to transmit and / or receive multiple frequency bands .This common aperture antenna having multiple frequency band received considerable attention in the recent years for their proper properties of adapting with change in the environmental and system requirement.

  10. MEMS Tunable Antennas

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


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

  11. Frequency scanning microstrip antennas

    Danielsen, Magnus; Jørgensen, Rolf


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

  12. Frequency selective lens antenna

    Thornton, J.; Haines, P.


    A variant of the hemispherical microwave lens antenna is reported where the ground plane region is modified through use of a frequency selective surface. This allows discrimination of frequencies by two closely spaced primary feeds. A scale model is reported operating at 12 and 30 GHz.

  13. Community Antenna Television (CATV).

    Federal Communications Commission, Washington, DC.

    The number of households hooked up to cable television or community antenna television (CATV) is expanding rapidly, and Federal Communications Commission (FCC) has been developing regulations since 1962 to guide the growth of the industry. By 1965 the FCC had claimed jurisdiction over all CATV systems in the U. S. This jurisdiction was challenged…

  14. Evolutionary optimization of optical antennas

    Feichtner, Thorsten; Kiunke, Markus; Hecht, Bert


    The design of nano-antennas is so far mainly inspired by radio-frequency technology. However, material properties and experimental settings need to be reconsidered at optical frequencies, which entails the need for alternative optimal antenna designs. Here a checkerboard-type, initially random array of gold cubes is subjected to evolutionary optimization. To illustrate the power of the approach we demonstrate that by optimizing the near-field intensity enhancement the evolutionary algorithm finds a new antenna geometry, essentially a split-ring/two-wire antenna hybrid which surpasses by far the performance of a conventional gap antenna by shifting the n=1 split-ring resonance into the optical regime.

  15. Antenna theory analysis and design

    Balanis, Constantine A


    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

  16. Adaptive cancellation techniques


    An adaptive signal canceller has been evaluated for the enhancement of pulse signal reception during the transmission of a high power ECM jamming signal. The canceller design is based on the use of DRFM(Digital RF Memory) technology as part of an adaptive multiple tapped delay line. The study includes analysis of relationship of tap spacing and waveform bandwidth, survey of related documents in areas of sidelobe cancellers, transversal equalizers, and adaptive filters, and derivation of control equations and corresponding control processes. The simulation of overall processes included geometric analysis of the multibeam transmitting antenna, multiple reflection sources and the receiving antenna; waveforms, tap spacings and bandwidths; and alternate control algorithms. Conclusions are provided regarding practical system control algorithms, design characteristics and limitations.

  17. BER Performance Evaluation of two Types of Antenna Array-Based Receivers in a Multipath Channel

    Rim Haddad


    Full Text Available Smart antennasystems have received much attention in the last few years because they can increasesystem capacity by dynamically tuning out interference while focusing on the intended user.In this paper, we focused our research on the performance of two kinds of smart antenna receivers. Ananalytical model is proposed for evaluating the BER performance using a closed-form expression. Also,for the adaptive array, a simple way to account the multi-access interference can be exploited to evaluatethe average probability of error when the users are randomly distributed within an angular sector.The proposed model confirms the benefits of adaptive antennas in reducing the overall interference level(intercell/intracell and to find an accurate approximation of the error probability.In the two kinds of receivers, we assessed the impact of smart antenna systems and we considered thecase of conventional single antenna receiver model as reference (single user/single antenna.


    Li Ke; Shi Xinhua; Zhang Eryang


    Multiple Access Interference(MAI) is the major factor that degrades the performance of a CDMA system. In this paper, a novel transform domain algorithm combined with parameter estimation for MAI suppression is proposed. Compared with the method that combines an adaptive array antenna with parameter estimation for interference suppression, it converges faster with the same Bit Error Rate(BER) performance.

  19. Design of Miniaturized Dual-Band Microstrip Antenna for WLAN Application.

    Yang, Jiachen; Wang, Huanling; Lv, Zhihan; Wang, Huihui


    Wireless local area network (WLAN) is a technology that combines computer network with wireless communication technology. The 2.4 GHz and 5 GHz frequency bands in the Industrial Scientific Medical (ISM) band can be used in the WLAN environment. Because of the development of wireless communication technology and the use of the frequency bands without the need for authorization, the application of WLAN is becoming more and more extensive. As the key part of the WLAN system, the antenna must also be adapted to the development of WLAN communication technology. This paper designs two new dual-frequency microstrip antennas with the use of electromagnetic simulation software-High Frequency Structure Simulator (HFSS). The two antennas adopt ordinary FR4 material as a dielectric substrate, with the advantages of low cost and small size. The first antenna adopts microstrip line feeding, and the antenna radiation patch is composed of a folded T-shaped radiating dipole which reduces the antenna size, and two symmetrical rectangular patches located on both sides of the T-shaped radiating patch. The second antenna is a microstrip patch antenna fed by coaxial line, and the size of the antenna is diminished by opening a stepped groove on the two edges of the patch and a folded slot inside the patch. Simulation experiments prove that the two designed antennas have a higher gain and a favourable transmission characteristic in the working frequency range, which is in accordance with the requirements of WLAN communication. PMID:27355954

  20. Search space scanning with planar electronically-controlled array antennas

    Hanle, E.

    The demands which radar installations have to satisfy are rising with increasing traffic density in the case of civil applications and a growing threat level in the case of the military sector. In many instances, these demands can only be met by adapting the value of the transmitted power to the traffic density or the magnitude of the threat. Such an approach requires the employment of computer-aided radar systems with electronically-controlled antennas. The considered systems have currently also advantages with respect to reliability and cost effectiveness. The present investigation is concerned with suitable procedures for the improvement of the energy management, taking into account mainly aspects of radar control and signal processing. The discussion is based on the consideration of a planar array antenna. Differences arising in connection with the use of other types of antennas are also briefly examined. The employment of an immobile radar antenna for ground-based airspace observation is considered. Attention is given to the appropriate selection of the width of the lobe, the scanning, the tilt of the antenna, and antenna performance characteristics.

  1. Omnidirectional Circularly Polarized Antennas – a Small Antenna Perspective

    Narbudowicz, Adam; Ammann, Max


    The paper discusses recent developments and challenges in the design of small omnidirectionalcircularly-polarized (CP) antennas. Although omnidirectional CP coverage is easily achievable usingantenna arrays, it is just recently that small and low-cost antennas delivered this functionality.The paper addresses practical design problems for these antennas, not reported in previous publications.This includes selection of the omnidirectional plane relative to the ground plane and measurement chall...

  2. Numerical analysis of patch antenna as antenna array element

    Kizimenko, V.; Bobkov, Y


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

  3. Microsecond switchable thermal antenna

    Ben-Abdallah, Philippe, E-mail:; Benisty, Henri; Besbes, Mondher [Laboratoire Charles Fabry, UMR 8501, Institut d' Optique, CNRS, Université Paris-Sud 11, 2, Avenue Augustin Fresnel, 91127 Palaiseau Cedex (France)


    We propose a thermal antenna that can be actively switched on and off at the microsecond scale by means of a phase transition of a metal-insulator material, the vanadium dioxide (VO{sub 2}). This thermal source is made of a periodically patterned tunable VO{sub 2} nanolayer, which support a surface phonon-polariton in the infrared range in their crystalline phase. Using electrodes properly registered with respect to the pattern, the VO{sub 2} phase transition can be locally triggered by ohmic heating so that the surface phonon-polariton can be diffracted by the induced grating, producing a highly directional thermal emission. Conversely, when heating less, the VO{sub 2} layers cool down below the transition temperature, the surface phonon-polariton cannot be diffracted anymore so that thermal emission is inhibited. This switchable antenna could find broad applications in the domain of active thermal coatings or in those of infrared spectroscopy and sensing.

  4. 47 CFR 80.863 - Antenna system.


    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Antenna system. 80.863 Section 80.863... Antenna system. (a) An antenna system must be installed which is as nondirectional and as efficient as is... construction of the required antenna must insure operation in time of emergency. (b) If the required antenna...

  5. 47 CFR 80.866 - Spare antenna.


    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Spare antenna. 80.866 Section 80.866... Spare antenna. A spare transmitting antenna completely assembled for immediate erection must be provided. If the installed transmitting antenna is suspended between supports, this spare antenna must be...

  6. Analysis and design of plasma monopole antenna

    Wei, Li; Jinghui, Qiu; Ying, Suo


    Two kinds of plasma monopole antennas are simulated and analyzed in this article. For different radius, reflection coefficient, radiation pattern and radiation efficiency of a cylindrical plasma monopole antenna are calculated respectively. According to actual situation, a conical plasma monopole antenna with different cone angle is simulated. Impedance and radiation characteristics of the plasma antenna are similar to the metal monopole antenna.

  7. Helicopter Rotor Antenna

    Pogorzelski, Ronald J.; Cable, Vaughn P.


    This effort was directed toward demonstration of the efficacy of a concept for mitigation of the rotor blade modulation problem in helicopter communications. An antenna is envisioned with radiating elements mounted on the rotor and rotating with it. The rf signals are coupled to the radio stationary with respect to the airframe via a coupler of unique design. The coupler has an rf cavity within which a mode is established and the field distribution of this mode is sampled by probes rotating with the radiating elements. In this manner the radiated pattern is "despun" with respect to the rotor. Theoretical analysis has indicated that this arrangement will be less susceptible to rotor blade modulation that would be a conventional fixed mounted antenna. A small coupler operating at S-band was designed, fabricated, and mounted on a mockup representative of a helicopter body. A small electric motor was installed to rotate the rotor portion of the coupler along with a set of radiating elements during testing. This test article was be evaluated using the JPL Mesa Antenna Measurement Facility to establish its ability to mitigate rotor blade modulation. It was found that indeed such a coupler will result in a despun pattern and that such a pattern can be effective in mitigation of rotor blade modulation.

  8. Microstrip antenna theory and design

    James, J. R.; Hall, P. S.; Wood, C.

    Microstrip is the name given to a type of open waveguiding structure which is now commonly used in present-day electronics, not only as a transmission line but for circuit components such as filters, couplers, and resonators. The idea of using microstrip to construct antennas is a much more recent development. The purpose of this monograph is to present the reader with an appreciation of useful antenna design approaches and the overall state-of-the art situation. Flat-plate antenna techniques and constraints on performance are considered along with microstrip design equations and data, the radiation mechanism of an open-circuit microstrip termination and the resulting design implications, the basic methods of calculation and design of patch antennas, and linear array techniques. Attention is also given to techniques and design limitations in two-dimensional arrays, circular polarization techniques, manufacturing and operational problems of microstrip antennas, recent advances in microstrip antenna analysis, and possible future developments.

  9. Antenna structure with distributed strip

    Rodenbeck, Christopher T.


    An antenna comprises electrical conductors arranged to form a radiating element including a folded line configuration and a distributed strip configuration, where the radiating element is in proximity to a ground conductor. The folded line and the distributed strip can be electrically interconnected and substantially coplanar. The ground conductor can be spaced from, and coplanar to, the radiating element, or can alternatively lie in a plane set at an angle to the radiating element. Embodiments of the antenna include conductor patterns formed on a printed wiring board, having a ground plane, spacedly adjacent to and coplanar with the radiating element. Other embodiments of the antenna comprise a ground plane and radiating element on opposed sides of a printed wiring board. Other embodiments of the antenna comprise conductors that can be arranged as free standing "foils". Other embodiments include antennas that are encapsulated into a package containing the antenna.

  10. Antenna Calibration and Measurement Equipment

    Rochblatt, David J.; Cortes, Manuel Vazquez


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

  11. A Compact UWB Diversity Antenna

    Hui Zhao


    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.

  12. Integrated, Dual Orthogonal Antennas for Polarimetric Ground Penetrating Radar

    Pauli, Mario; Wiesbeck, Werner


    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

  13. Broadband Loaded Cylindrical Monopole Antenna

    Boucher, Solene; Sharaiha, Ala; Potier, Patrick


    Ahstract-A broadband printed monopole antenna based on the variation of the conductivity along its length is proposed .. The result indicates that a non-monotonous repartition provides interesting performances in terms of impedance bandwidth but also concerning antenna gain. The achievement of the method is demonstrated through its application, using the carbon fibers to perform this conductivity variation. Monopole antenna presents a large impedance bandwidth of 123% with an interesting gain...

  14. UWB Directive Triangular Patch Antenna

    A. C. Lepage


    Full Text Available Compact directive UWB antennas are presented in this paper. We propose an optimization of the F-probe fed triangular patch antenna. The new design achieves an impedance bandwidth of 69% (3–6.15 GHz and presents good radiation characteristics over the whole impedance bandwidth. The average gain is 6.1 dB. A time-domain study has been performed to characterize the antenna behavior in case a UWB pulse is used. Finally, we propose an alternative solution to facilitate the manufacturing process using metallized foam technology. It also improves the robustness of the antenna as well as reducing its cost.

  15. Antenna arrays a computational approach

    Haupt, Randy L


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

  16. Hybrid Maritime Satellite Communication Antenna

    Smith, Thomas Gunst

    Hybrid antennas for a maritime satellite communication terminal with simultaneous operation at L- and Ka-band have been investigated. The frequency bands of interest are 1; 525:0 1; 660:5 MHz (RX+TX, RHCP), 19:7 20:2 (RX, LHCP) and 29:5 30:0 GHz (TX, RHCP), which are all part of the Inmarsat BGAN...... and Inmarsat GX services, respectively. The results of this study are three antenna concepts, which demonstrates high performance at both L- and Ka-band. A combined single/dual-reflector antenna is designed, which presents a favourable way of combining feed antennas for the diverse frequencies. This...... antenna enables the use of a conventional horn-fed dual-reflector for Ka-band, while a backfire helical antenna is used to form a single-reflector antenna at L-band. Simulations show excellent performance of the L-band backfire helical reflector antenna, due to the utilization of the entire antenna...

  17. Minimum Q Electrically Small Antennas

    Kim, O. S.


    Theoretically, the minimum radiation quality factor Q of an isolated resonance can be achieved in a spherical electrically small antenna by combining TM1m and TE1m spherical modes, provided that the stored energy in the antenna spherical volume is totally suppressed. Using closed-form expressions...... results for a multiarm spherical helix antenna confirm the theoretical predictions. For example, a 4-arm spherical helix antenna with a magnetic-coated perfectly electrically conducting core (ka=0.254) exhibits the Q of 0.66 times the Chu lower bound, or 1.25 times the minimum Q....

  18. Modified antenna for orthogonally polarised fields

    Prudyus, Ivan N.; Zakharia, Y. A.; Storozh, V. G.; Mankovsky, S. V.


    A compact wideband antenna for transmission and receiving of orthogonally polarized electromagnetic fields is proposed. Results of electrodynamic antenna structure analysis are considered. Main antenna properties by results of experimental investigation are presented.

  19. Ultrawideband method of feeding a dipole antenna

    Bakhrakh, Lev D.; Los', V. F.; Shamanov, A. N.


    An antenna-feeder device is considered, in which a new way of antenna excitation is implemented. An example is presented of its use with a dipole antenna for the radiation of super-short pulse signals.

  20. Antenna system for measuring electromagnetic field parameters

    Ilnitskiy, Ludvig Ya.; Shcherbyna, Olga A.


    A functional block diagram of the general-purpose antenna system for measuring electromagnetic wave parameters has been presented. Theoretical relationships forming a basis of the antenna system structure are described, and the antenna operation principle is presented.

  1. Ferrite attenuator modulation improves antenna performance

    Hooks, J. C.; Larson, S. G.; Shorkley, F. H.; Williams, B. T.


    Ferrite attenuator inserted into appropriate waveguide reduces the gain of the antenna element which is causing interference. Modulating the ferrite attenuator to change the antenna gain at the receive frequency permits ground tracking until the antenna is no longer needed.

  2. Design aspects of commercial satellite antennas

    Lang, K. C.; Taormina, F. A.

    General design considerations for commercial satellite antennas are reviewed, and design factors of shaped beam reflector antennas are described, including shaped beam efficiency, flat-topping and boundary matching, and analysis by Fourier transforms. Attention is then given to the design of the Telesat Anik 17/Westar/Palapa communications antenna, the Comstar I communications antenna, the SBS communications antenna, and Intelsat IV A communications antenna.

  3. Ultra wideband antennas design, methodologies, and performance

    Galvan-Tejada, Giselle M; Jardón Aguilar, Hildeberto


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

  4. Broadband Corrugated Square-Shaped Monopole Antenna

    S. D. Ahirwar; C. Sairam


    Design and development of a corrugated square-shaped monopole antenna is presented with measured results. The operational bandwidth of the antenna is 300 MHz–3000 MHz. The antenna is derived from a square-shaped planar monopole antenna. This basic square-shaped radiating element is corrugated in its lateral dimension. This corrugation reduces the lateral dimension of the antenna by 60%. Electrical performance of this antenna is better than its parent counterpart. This paper presents design an...

  5. UWB and SWB Planar Antenna Technology

    Zhong, Shun-Shi


    The recent progress in the development of UWB planar antenna technology has been reviewed. Some types of UWB metal-plate monopole antennas, UWB printed monopole antennas and UWB printed slot antennas are presented. The comparison results of indicate that the UWB printed monopole antennas can realize relatively smaller dimensions, and that the UWB printed slot antennas can achieve relatively higher gain. Finally, some realization manners of the band-notch function of UWB printed monopole anten...

  6. Design of Antennas for RFID Application

    Zhang, Ming-Tao; Jiao, Yong-Chang; Zhang, Fu-Shun; Wang, Wu-Tu


    In this chapter, the antenna in RFID system is discussed, and the design of antenna is also described. The main contents include the status of the antenna in the RFID system, the design method for the antenna, the power transmission between the tag chip and the tag antenna, the tag antenna design, the scheme and design for the circular polarization, and the design of antenna for microwave band RFID tag. These researches almost cover all problems of the antenna encountering in the RFID applica...

  7. Analysis of RF Front-End Performance of Reconfigurable Antennas with RF Switches in the Far Field

    Insu Yeom


    Full Text Available The RF front-end performances in the far-field condition of reconfigurable antennas employing two commonly used RF switching devices (PIN diodes and RF-MEMS switches were compared. Two types of antennas (monopole and slot representing general direct/coupled feed types were used for the reconfigurable antennas to compare the excited RF power to the RF switches by the reconfigurable antenna types. For the switching operation of the antennas, a biasing circuit was designed and embedded in the same antenna board, which included a battery to emphasize the antenna’s adaptability to mobile devices. The measurement results of each reconfigurable antenna (radiation patterns and return losses are presented in this study. The receiving power of the reference antenna was measured by varying the transmitting power of the reconfigurable antennas in the far-field condition. The receiving power was analyzed using the “Friis transmission equation” and compared for two switching elements. Based on the results of these measurements and comparisons, we discuss what constitutes an appropriate switch device and antenna type for reconfigurable antennas of mobile devices in the far-field condition.

  8. Patch antenna terahertz photodetectors

    We report on the implementation of 5 THz quantum well photodetector exploiting a patch antenna cavity array. The benefit of our plasmonic architecture on the detector performance is assessed by comparing it with detectors made using the same quantum well absorbing region, but processed into a standard 45° polished facet mesa. Our results demonstrate a clear improvement in responsivity, polarization insensitivity, and background limited performance. Peak detectivities in excess of 5 × 1012 cmHz1/2/W have been obtained, a value comparable with that of the best cryogenic cooled bolometers

  9. Ultra wide band antennas

    Begaud, Xavier


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

  10. Terahertz antenna electronic chopper

    Sterczewski, L. A., E-mail:; Grzelczak, M. P.; Plinski, E. F. [Department of Electronics, Wroclaw University of Technology, 27 Wybrzeze Wyspianskiego St., 50-370 Wroclaw (Poland)


    In this paper, we present an electronic circuit used to bias a photoconductive antenna that generates terahertz radiation. The working principles and the design process for the device are discussed in detail. The noise and shape of the wave measurements for a built device are considered. Furthermore, their impact on a terahertz pulse and its spectra is also examined. The proposed implementation is simple to build, robust and offers a real improvement over THz instrumentation due to the frequency tuning. Additionally, it provides for galvanic isolation and ESD protection.

  11. Broadband antenna with frequency scanning

    A. A. Shekaturin


    Full Text Available Relevance of this study. The main advantage of frequency scanning is simplicity of implementation. At this point, multifunctional usage of microwave modules is an urgent task, as well as their maximum simpler and cheaper. Antenna design and operation. The study is aimed at providing electric antenna with frequency scanning. It was based on the log-periodic antenna due to its wideband and negotiation capability over the entire operating frequency range. For this distribution line is bent in an arc of a circle in a plane blade while vibrators are arranged along the radius. Computer modeling of antennas with frequency scanning. Modeled with a non-mechanical motion antenna beam emitters representing system for receiving a radio frequency signal on mobile objects calculated for 1.8 GHz ... 4.2 GHz. The simulation was performed in a software environment for numerical modeling of electromagnetic «Feko 5.5». Analysis of the interaction of radiation is based on the method of moments. Findings. The result of this work is to propose a new design of the antenna with a frequency scanning method as agreed in a wide frequency range. In the studied technical solution provided by the rotation of NAM in the frequency range, and the matching of the antenna to the feed line is maintained. Application of this type of antennas on the proposed technical solution in communication systems will improve the communication reliability by maintaining coordination in the frequency range

  12. Slot-Coupled Barbel Antenna

    Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne


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

  13. Coupling between minimum scattering antennas

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


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

  14. Graphene-antenna sandwich photodetector.

    Fang, Zheyu; Liu, Zheng; Wang, Yumin; Ajayan, Pulickel M; Nordlander, Peter; Halas, Naomi J


    Nanoscale antennas sandwiched between two graphene monolayers yield a photodetector that efficiently converts visible and near-infrared photons into electrons with an 800% enhancement of the photocurrent relative to the antennaless graphene device. The antenna contributes to the photocurrent in two ways: by the transfer of hot electrons generated in the antenna structure upon plasmon decay, as well as by direct plasmon-enhanced excitation of intrinsic graphene electrons due to the antenna near field. This results in a graphene-based photodetector achieving up to 20% internal quantum efficiency in the visible and near-infrared regions of the spectrum. This device can serve as a model for merging the light-harvesting characteristics of optical frequency antennas with the highly attractive transport properties of graphene in new optoelectronic devices. PMID:22703522

  15. DEA deformed stretchable patch antenna

    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)

  16. Antenna Miniaturization in Complex Electromagnetic Environments

    Zhang, Jiaying

    - less communication system into the heading-aids, and these are the antenna miniaturization, the measurement techniques for electrically small antennas and the influence of complex environments on the characteristics of electrically small antennas, respectively. Antenna MiniaturizationIn this...... dissertation, we present several novel designs of electrically small loop antennas for the hearing-aid application. First antenna design is a two-dimensional (2-D) planar differential-fed electrically small loop. The working mechanism of this antenna is based on the capacitive loading and the induc- tive...... coupling between two small loops. An analytical model, simulations, fabrications and measurements are presented for this antenna. Second antenna design is a planar two-turn electrically small loop antenna. The work- ing mechanism of this antenna is based on the capacitive loading, and both the capacitive...

  17. On chip plasmonic monopole nano-antennas and circuits.

    Adato, Ronen; Yanik, Ahmet A; Altug, Hatice


    Analogues of many radio frequency (RF) antenna designs such as the half-wave dipole and Yagi-Uda have been successfully adapted to the optical frequency regime, opening the door for important advances in biosensing, photodetection, and emitter control. Examples of monopole antennas, however, are conspicuously rare given the element's extensive use in RF applications. Monopole antennas are attractive as they represent an easy to engineer, compact geometry and are well isolated from interference due the ground plane. Typically, however, the need to orient the antenna element perpendicular to a semi-infinite ground plane requires a three-dimensional structure and is incompatible with chip-based fabrication techniques. We propose and demonstrate here for the first time that monopole antenna elements can be fashioned out of single element nanoparticles fabricated in conventional planar geometries by using a small nanorod as a wire reflector. The structure offers a compact geometry and the reflector element provides a measure of isolation analogous to the RF counterpart. This isolation persists in the conductive coupling regime, allowing multiple monopoles to be combined into a single nanoparticle, yet still operate independently. This contrasts with several previous studies that observed dramatic variations in the spectral response of conductively coupled particles. We are able to account for these effects by modeling the system using circuit equations from standard RF antenna theory. Our model accurately describes this behavior as well as the detailed resonance tuning of the structure. As a specific practical application, the monopole resonances are precisely tuned to desired protein absorption bands, thereby enhancing their spectroscopic signatures. Furthermore, the accurate modeling of conductive coupling and demonstrated electronic isolation should be of general interest to the design of complex plasmonic circuits incorporating multiple antennas and other current

  18. Transcatheter Microwave Antenna

    Arndt, Dickey G. (Inventor); Carl, James R. (Inventor); Ngo, Phong (Inventor); Raffoul, George W. (Inventor)


    A method, simulation, and apparatus are provided that are highly suitable for treatment of benign prostatic hyperplasia (BPH). A catheter is disclosed that includes a small diameter disk loaded monopole antenna surrounded by fusion material having a high heat of fusion and a melting point preferably at or near body temperature. Microwaves from the antenna heat prostatic tissue to promote necrosing of the prostatic tissue that relieves the pressure of the prostatic tissue against the urethra as the body reabsorbs the necrosed or dead tissue. The fusion material keeps the urethra cool by means of the heat of fusion of the fusion material. This prevents damage to the urethra while the prostatic tissue is necrosed. A computer simulation is provided that can be used to predict the resulting temperature profile produced in the prostatic tissue. By changing the various control features of the catheter and method of applying microwave energy a temperature profile can be predicted and produced that is similar to the temperature profile desired for the particular patient.

  19. Analysis of dielectric antennas by a diffraction method

    Mahdjoubi, K.; Terret, C.


    Performance comparisons and assessment of the compatibility of microstrip patch antennas and leaky-wave dielectric antennas for millimeter wave communications are presented. The antennas are formed of scattering material, placed in the near field of the excitation source, and equipped with circular waveguides functioning in the fundamental mode. An integral formulation is devised for the diffraction field around the antennas with either homogeneous or composite structures. The calculations center around a singularity and are expressed by means of the Green function, which is solved by a method of moments technique involving point-segments. An approximate solution is defined for diffraction in the near field for a body of revolution, and experimental results are provided for the directivity of the radiation from a source in two planes of polarization. The calculations are applied to scattering by a dielectric body using the method of volumic equivalence, showing good agreement with experimental values, particularly when a good adaptation is made between the dielectric bodies and the waveguide source. The equivalence method is suggested to be suitable for modeling the diffraction field around heterogeneous antennas.


    P.P. Edwin Winston


    Full Text Available Wireless systems have recently been becoming faster and more intelligent. However the high speed access and intelligence make the power consumption of wireless systems high. In the WiMAX system, the MS transmission power is controlled in order to avoid exceeding the BS’s total receiving power from an antenna. Conventional wireless network design has long used base site sectorization and single, omni-directional antennas at the enduser device to serve the communications link, with advanced multi-antenna implementations operators have a new suite of tools to develop the robust wireless networks of the future. Revolutionary multiple antenna techniques at the base station and end-user device, paired with sophisticated signal processing and power consumption control, can dramatically improve the communications link for the most demanding applicationscenarios including heavily obstructed propagation environments and high speed mobility service. This paper presents results of an experimental study, simulation based, directed to determine the optimum transmission power and Antenna gain which influence on the overall handover performance in mobility scenarios, related toWiMAX communications. Based on them, optimal parameter sets can be provided by the network operator to mobile station, to guide its adaptation of the major WiMAX parameters to its speed and network topology and to help the handover decision.

  1. SAR Experiments Using a Conformal Antenna Array Radar Demonstrator

    Peter Knott


    Full Text Available Conformal antenna arrays have been studied for several years but only few examples of applications in modern radar or communication systems may be found up to date due to technological difficulties. The objective of the “Electronic Radar with Conformal Array Antenna” (ERAKO demonstrator system which has been developed at the Fraunhofer Institute for High Frequency Physics and Radar Techniques (FHR is to demonstrate the feasibility of an active electronically scanned antenna for conformal integration into small and medium sized airborne platforms. For practical trials the antenna has been adapted for operation with the Phased Array Multifunctional Imaging Radar (PAMIR system developed at the institute. The antenna in combination with the PAMIR front-end needed to undergo a special calibration procedure for beam forming and imaging post-processing. The present paper describes the design and development of the conformal antenna array of the demonstrator system, its connection to the PAMIR system and results of recently conducted synthetic aperture radar (SAR experiments.

  2. The Mutual Interaction effects between Array Antenna Parameters and Receiving Signals Bandwidth

    Shahad D. Sateaa


    Full Text Available The presence of a single complex adaptive weight in each element channel of an adaptive array antenna is sufficient for processing of narrowband signals. The ability of an adaptive array antenna to null interference deteriorates rapidly as the interference bandwidth increases. The performance of narrowband adaptive array antenna with LMCV Beamforming algorithm is examined. The interaction effects between received signal angle of arrival and array parameters like the interelement spacing and the number of array element and the received signal bandwidth were studied. The output Signal to Interference plus Noise Ratio (SINR and Interference to Noise Ratio (INR are used as performance parameters for evaluation of these effects. It is found that the amount of degradation in the output SINR is increased significantly with the increase of array interelement spacing, number of array elements and when the angle of arrival of received signals are closet to end fire.

  3. Metamaterial antennas: the most successful metamaterial technology?

    Breinbjerg, Olav


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

  4. 47 CFR 73.753 - Antenna systems.


    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 73.753 Section 73.753... International Broadcast Stations § 73.753 Antenna systems. All international broadcasting stations shall operate with directional antennas. Such antennas shall be designed and operated so that the radiated power...

  5. 47 CFR 95.51 - Antenna height.


    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Antenna height. 95.51 Section 95.51... SERVICES General Mobile Radio Service (GMRS) § 95.51 Antenna height. (a) Certain antenna structures used in... this chapter. (b) The antenna for a small base station or for a small control station must not be...

  6. 47 CFR 73.510 - Antenna systems.


    ... 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....

  7. Group Delay of High Q Antennas

    Bahramzy, Pevand; Pedersen, Gert Frølund


    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....

  8. Design of a New Model of Multiband Miniature Antenna Near Isotropic

    Abdellatif Berkat


    Full Text Available In this paper, we propose a new slotted multiband antennas simulated at different frequencies. The insertion of slots in the patch gives a good adapting frequency with various forms on the radiation pattern. The main feature of the proposed antenna is the capability to generate a near isotropic radiation pattern in different frequencies .The design details of the conceived antenna are presented and discussed. Simulations of the different reflection coefficient and radiation pattern are presented. These were carried out using CST Microwave Studio. This model has got numerous applications in network sensors, field measurements and electromagnetic compatibility.

  9. A New Half-blind Algorithm of Smart Antenna for Mobile Terminal

    Yuan Li


    Full Text Available The core of smart antenna is its adaptive algorithm. For the characteristics of TD-SCDMA mobile terminal, we analyze the advantages and disadvantages of various algorithms and propose a semi-blind algorithm combining the NLMS algorithm and the CMA algorithm in this paper. The new semi-blind algorithm has strong robustness and low complexity. It is suitable for smart antenna of TD-SCDMA mobile terminals.

  10. Metal Patch Antenna

    Chamberlain, Neil F. (Inventor); Hodges, Richard E. (Inventor); Zawadzki, Mark S. (Inventor)


    Disclosed herein is a patch antenna comprises a planar conductive patch attached to a ground plane by a support member, and a probe connector in electrical communication with the conductive patch arranged to conduct electromagnetic energy to or from the conductive patch, wherein the conductive patch is disposed essentially parallel to the ground plane and is separated from the ground plane by a spacing distance; wherein the support member comprises a plurality of sides disposed about a central axis oriented perpendicular to the conductive patch and the ground plane; wherein the conductive patch is solely supported above the ground plane by the support member; and wherein the support member provides electrical communication between the planer conductive patch and the ground plane.

  11. Antenna sunshield membrane

    Bogorad, Alexander (Inventor); Bowman, Jr., Charles K. (Inventor); Meder, Martin G. (Inventor); Dottore, Frank A. (Inventor)


    An RF-transparent sunshield membrane covers an antenna reflector such as a parabolic dish. The blanket includes a single dielectric sheet of polyimide film 1/2-mil thick. The surface of the film facing away from the reflector is coated with a transparent electrically conductive coating such as vapor-deposited indium-tin oxide. The surface of the film facing the reflector is reinforced by an adhesively attached polyester or glass mesh, which in turn is coated with a white paint. In a particular embodiment of the invention, polyurethane paint is used. In another embodiment of the invention, a layer of paint primer is applied to the mesh under a silicone paint, and the silicone paint is cured after application for several days at room temperature to enhance adhesion to the primer.


    P. Jithu


    Full Text Available The WLAN and Bluetooth applications become popular in mobile devices, integrating GSM and ISM bands operation in one compact antenna, can reduce the size of mobile devices. Recently, lot many investigations are carried out in designing a dual band antennas with operating frequencies in GSM band and in ISM band for mobile devices. Printed monopoles are under this investigation. In this paper, dual-band printed monopoles are presented to operate at GSM band i.e. 900 MHz and ISM band i.e. 2.4 GHz. We intend to observe the antenna characteristics on the network analyzer and verify the theoretical results with the practical ones.

  13. Measurement of mobile antenna systems

    Arai, Hiroyuki


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

  14. Microstrip and printed antenna design

    Bancroft, Randy


    The approach in this book is historical and practical. It covers abasic designsa in more detail than other microstrip antenna books that tend to skip important electrical properties and implementation aspects of these types of antennas. Examples include: quarter-wave patch, quarter by quarter patch, detailed design method for rectangular circularly polarized patch, the use of the TM11 (linear and broadside CP), TM21 (monopole CP pattern) and TM02 (monopole linear) circular patch modes in designs, dual-band antenna designs which allow for independent dual-band frequencies. Limits on broadband m

  15. Absorption Efficiency of Receiving Antennas

    Andersen, Jørgen Bach; Frandsen, Aksel


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

  16. Semi hemi antenna. [balloon parachuted microwave antenna for stratospheric testing

    Repucci, T. A.; Ferris, J. E.


    The University of Michigan minipod, which is released from a balloon and floats down on a parachute, is designed for stratospheric testing. The present paper briefly describes the evolution of antenna designs for the minipod 1.5 GHz transceiver, which communicates with and relays information to an aircraft and ground station. The following stages are noted: ordinary monopole, crossed dipole, capacitative antenna, fat monopole, the addition of parasitic elements, and a thinner monopole with taper.

  17. Design of Combined Antenna with Multiple Polarizations

    Zineb Berkat; Noureddine Boukli Hacene; Abdellatif Berkat


    In this paper, we present a design of new combined antenna, mixing both linear and circular polarizations, new antenna have to be able to cover several frequency bandwidths, including various radiation properties. From the different researches of antenna with various geometries, and regarding the complexity to combine in a single radiating element several types of polarizations. It is extremely important that the development of antenna used in Wireless Systems. The proposed antenna is simulat...

  18. Electrically floating, near vertical incidence, skywave antenna

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


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

  19. Bacteria Foraging Algorithm in Antenna Design

    Biswa Binayak Mangaraj; Manas Ranjan Jena; Saumendra Kumar Mohanty


    A simple design procedure to realize an optimum antenna using bacteria foraging algorithm (BFA) is proposed in this paper. The first antenna considered is imaginary. This antenna is optimized using the BFA along with a suitable fitness function formulated by considering some performance parameters and their best values. To justify the optimum design approach, one 12-element Yagi-Uda antenna is considered for an experiment. The optimized result of this antenna obtained using the optimization a...

  20. Prototyping Neuroadaptive Smart Antenna for 3G Wireless Communications

    To William


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

  1. Prototyping Neuroadaptive Smart Antenna for 3G Wireless Communications

    To William; Salcic Zoran; Nguang Sing Kiong


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

  2. Electrically-driven optical antennas

    Kern, Johannes; Prangsma, Jord C; Emmerling, Monika; Kamp, Martin; Hecht, Bert


    Unlike radiowave antennas, optical nanoantennas so far cannot be fed by electrical generators. Instead, they are driven by light or via optically active materials in their proximity. Here, we demonstrate direct electrical driving of an optical nanoantenna featuring an atomic-scale feed gap. Upon applying a voltage, quantum tunneling of electrons across the feed gap creates broadband quantum shot noise. Its optical frequency components are efficiently converted into photons by the antenna. We demonstrate that the properties of the emitted photons are fully controlled by the antenna architecture, and that the antenna improves the quantum efficiency by up to two orders of magnitude with respect to a non-resonant reference system. Our work represents a new paradigm for interfacing electrons and photons at the nanometer scale, e.g. for on-chip wireless data communication, electrically driven single- and multiphoton sources, as well as for background-free linear and nonlinear spectroscopy and sensing with nanometer...

  3. Circularly-Polarized Microstrip Antenna

    Stanton, P. H.


    Microstrip construction compact for mobile applications. Circularly polarized microstrip antenna made of concentric cylindrical layers of conductive and dielectric materials. Coaxial cable feedlines connected to horizontal and vertical subelements from inside. Vertical subelement acts as ground for horizontal subelement.

  4. Dual-frequency microwave antenna

    Bathker, D. A.; Brunstein, S. A.; Ludwig, A. C.; Potter, P. D.


    Single antenna using two feed horns (one for receiving and radiation X-band signals, and one for S-band signals), in conjunction with ellipsoid reflector and dichronic plate, can accommodate two different frequencies simultaneously.

  5. Inflatable Antennas Support Emergency Communication


    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.

  6. Dipoles, unintentional antennas and EMC

    Berend Danker


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

  7. Substrate Integrated Waveguide Antenna Applications

    Wu, Liang


    The research objective of this thesis is to provide a better solution for signal interference and reduce the size of waveguide antenna. The background investigations of different waveguide fabrication technologies and switch control methods are detailed in the introductory part of this thesis. Several novel substrate integrated waveguide (SIW) antennas for different purpose are demonstrated in the body of the thesis. The designs are mainly divided into two kinds. The first focuses on the ...

  8. Living antennas on communication satellites

    Lumholt, Michael


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

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

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


    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.

  10. Multiple band circularly polarized microstrip antenna

    Yu, I. P. (Inventor)


    A multiple antenna assembly for communicating electromagnetic radiation is disclosed. An antenna element stack is constructed of a plurality of elliptical lamina antenna elements mutally separated by layers of dielectric material, and separated from a ground plane by dielectric material. The antenna assembly is coupled through a feed line in contact with the top antenna element. A conductor joins the remaining antenna elements to the ground plane. Each individual antenna element is operable for communication reception and transmission within a frequency band determined by the size of the particular antenna element. The sizes of the antenna elements may be selected to provide electromagnetic radiation communication over several distinct frequency bands, or to connect the individual bands into a broad band.

  11. E-Textile Antennas for Space Environments

    Kennedy, Timothy F.; Fink, Patrick W.; Chu, Andrew W.


    The ability to integrate antennas and other radio frequency (RF) devices into wearable systems is increasingly important as wireless voice, video, and data sources become ubiquitous. Consumer applications including mobile computing, communications, and entertainment, as well as military and space applications for integration of biotelemetry, detailed tracking information and status of handheld tools, devices and on-body inventories are driving forces for research into wearable antennas and other e-textile devices. Operational conditions for military and space applications of wireless systems are often such that antennas are a limiting factor in wireless performance. The changing antenna platform, i.e. the dynamic wearer, can detune and alter the radiation characteristics of e-textile antennas, making antenna element selection and design challenging. Antenna designs and systems that offer moderate bandwidth, perform well with flexure, and are electronically reconfigurable are ideally suited to wearable applications. Several antennas, shown in Figure 1, have been created using a NASA-developed process for e-textiles that show promise in being integrated into a robust wireless system for space-based applications. Preliminary characterization of the antennas with flexure indicates that antenna performance can be maintained, and that a combination of antenna design and placement are useful in creating robust designs. Additionally, through utilization of modern smart antenna techniques, even greater flexibility can be achieved since antenna performance can be adjusted in real-time to compensate for the antenna s changing environment.

  12. Antenna Miniaturization with MEMS Tunable Capacitors

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


    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 and their...

  13. Vehicle antenna development for mobile satellite applications

    Woo, K.


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

  14. Modern lens antennas for communications engineering

    Thornton, John


    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

  15. Systems analysis for DSN microwave antenna holography

    Rochblatt, D. J.


    Proposed systems for Deep Space Network (DSN) microwave antenna holography are analyzed. Microwave holography, as applied to antennas, is a technique which utilizes the Fourier Transform relation between the complex far-field radiation pattern of an antenna and the complex aperture field distribution to provide a methodology for the analysis and evaluation of antenna performance. Resulting aperture phase and amplitude distribution data are used to precisely characterize various crucial performance parameters, including panel alignment, subreflector position, antenna aperture illumination, directivity at various frequencies, and gravity deformation. Microwave holographic analysis provides diagnostic capacity as well as being a powerful tool for evaluating antenna design specifications and their corresponding theoretical models.

  16. Single Band Helical Antenna in Axial Mode

    Parminder Singh


    Full Text Available Helical antennas have been widely used in a various useful applications, due to their low weight and low profile conformability, easy and cheap realization.Radiation properties of this antenna are examined both theoretically and experimentally. In this paper, an attempt has been made to investigate new helical antenna structure for Applications. CST MWS Software is used for the simulation and design calculations of the helical antennas. The axial ratio, return loss, VSWR, Directivity, gain, radiation pattern is evaluated. Using CST MWS simulation software proposed antenna is designed/simulated and optimized. The antenna exhibits a single band from 0 GHz to 3 GHz for GPS and several satellite applications

  17. Broadband Multilayered Array Antenna with EBG Reflector

    P. Chen


    Full Text Available Most broadband microstrip antennae are implemented in the form of slot structure or laminate structure. The impedance bandwidth is broadened, but meanwhile, the sidelobe of the directivity pattern and backlobe level are enlarged. A broadband stacked slot coupling microstrip antenna array with EBG structure reflector is proposed. Test results indicate that the proposed reflector structure can effectively improve the directivity pattern of stacked antenna and aperture coupled antenna, promote the front-to-back ratio, and reduce the thickness of the antenna. Therefore, it is more suitable to be applied as an airborne antenna.

  18. Antenna for passive RFID tags

    Schiopu, Paul; Manea, Adrian; Cristea, Ionica; Grosu, Neculai; Vladescu, Marian; Craciun, Anca-Ileana; Craciun, Alexandru


    Minuscule devices, called RFID tags are attached to objects and persons and emit information which positioned readers may capture wirelessly. Many methods of identification have been used, but that of most common is to use a unique serial number for identification of person or object. RFID tags can be characterized as either active or passive [1,2]. Traditional passive tags are typically in "sleep" state until awakened by the reader's emitted field. In passive tags, the reader's field acts to charge the capacitor that powers the badge and this can be a combination of antenna and barcodes obtained with SAW( Surface Acoustic Wave) devices [1,2,3] . The antenna in an RFID tag is a conductive element that permits the tag to exchange data with the reader. The paper contribution are targeted to antenna for passive RFID tags. The electromagnetic field generated by the reader is somehow oriented by the reader antenna and power is induced in the tag only if the orientation of the tag antenna is appropriate. A tag placed orthogonal to the reader yield field will not be read. This is the reason that guided manufacturers to build circular polarized antenna capable of propagating a field that is alternatively polarized on all planes passing on the diffusion axis. Passive RFID tags are operated at the UHF frequencies of 868MHz (Europe) and 915MHz (USA) and at the microwave frequencies of 2,45 GHz and 5,8 GHz . Because the tags are small dimensions, in paper, we present the possibility to use circular polarization microstrip antenna with fractal edge [2].

  19. Design of LTCC Based Fractal Antenna

    AdbulGhaffar, Farhan


    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.

  20. Wrap-rib antenna concept development overview

    Woods, A. A., Jr.; Garcia, N. F.


    The wrap rib antenna design of a parabolic reflector large space antenna is discussed. Cost estimates, design/mission compatibility, deployment sequence, ground based tests, and fabrication are discussed.

  1. High-temperature superconductor antenna investigations

    In this paper the use of superconductors to increase antenna radiation efficiency and gain is examined. Although the gain of all normal-metal antennas can be increased through the use of superconductors, some structures have greater potential for practical improvement than others. Some structures suffer a great degradation in bandwidth when replaced with superconductors, while for others the improvement in efficiency is trivial due to the minimal contribution of the conductor loss mechanism to the total losses, or the already high efficiency of the structure. The following antennas and related structures are discussed: electrically small antennas, impedance matching of antennas, microstrip antennas, microwave and millimeter-wave antenna arrays, and superdirective arrays. The greatest potential practical improvements occur for large microwave and millimeter-wave arrays and the impedance matching of antennas

  2. Microwave Antenna With Reduced Noise Leakage

    Cha, A. G.


    Gain or gain-to-temperature ratio of dual-shaped subreflector receiving antenna increased when illumination is tapered near aperture edge. Taper imposed in antenna feed reduces spillover in transmitting mode and reduces noise pickup in receiving mode.

  3. Integrated resonant tunneling diode based antenna

    Hietala, Vincent M. (Placitas, NM); Tiggers, Chris P. (Albuquerque, NM); Plut, Thomas A. (Albuquerque, NM)


    An antenna comprising a plurality of negative resistance devices and a method for making same comprising employing a removable standoff layer to form the gap between the microstrip antenna metal and the bottom contact layer.

  4. VLBI Antenna Calibration via GPS Project

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

  5. X-band data transmission antenna for Indian remote sensing satellite

    Lakshmeesha, V. K.; Nicholas, L.; Mahadevan, V.; Pal, S.

    This paper presents the development and performance of a shaped beam antenna for data transmission applications at X-band for a Low Earth Orbit, three-axis stabilized satellite. The shaped beam enables link optimization by making antenna gain and path loss profile combination to remain nearly constant over different elevation angles. The antenna generates circular polarization in circular waveguide by adapting a septum polarizer and achieves shape beam by the use of a small shaped subreflector in front of the mouth of the radiating waveguide and a large (300 mm) plane reflector positioned in the plane of the aperture. The antenna gain realized is 7 dBi for Right Circular Polarization.

  6. Antenna coupled photonic wire lasers.

    Kao, Tsung-Yu; Cai, Xiaowei; Lee, Alan W M; Reno, John L; Hu, Qing


    Slope efficiency (SE) is an important performance metric for lasers. In conventional semiconductor lasers, SE can be optimized by careful designs of the facet (or the modulation for DFB lasers) dimension and surface. However, photonic wire lasers intrinsically suffer low SE due to their deep sub-wavelength emitting facets. Inspired by microwave engineering techniques, we show a novel method to extract power from wire lasers using monolithically integrated antennas. These integrated antennas significantly increase the effective radiation area, and consequently enhance the power extraction efficiency. When applied to wire lasers at THz frequency, we achieved the highest single-side slope efficiency (~450 mW/A) in pulsed mode for DFB lasers at 4 THz and a ~4x increase in output power at 3 THz compared with a similar structure without antennas. This work demonstrates the versatility of incorporating microwave engineering techniques into laser designs, enabling significant performance enhancements. PMID:26191717

  7. Compact Low Frequency Radio Antenna

    Punnoose, Ratish J.


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

  8. Logarithmic Slots Antennas Using Substrate Integrated Waveguide

    Jahnavi Kachhia; Amit Patel,; Alpesh Vala; Romil Patel; Keyur Mahant


    This paper represents new generation of slotted antennas for satellite application where the loss can be compensated in terms of power or gain of antenna. First option is very crucial because it totally depends on size of satellite so we have proposed the high gain antenna creating number of rectangular, trapezoidal, and I shape slots in logarithm size in Substrate Integrated Waveguide (SIW) structure. The structure consists of an array of various shape slots antenna designed to operate in C ...

  9. Ultra-wideband RF helmet antenna

    Lebaric, Jovan; Tan, Ah-Tuan


    This paper addresses the development of an ultra-wideband, vertically polarized communications antenna integrated into the camouflage cover of a standard military-issue Kevlar helmet. The Helmet Camouflage Cover Antenna (referred to as the “helmet antenna’y is one of three antennas based on the antenna COMbat Wear INtegration (COMWIN) concept developed at the Naval Postgraduate School (NPS) for the man -portable implementation of the new Joint Tactical Radio System (JTRS). The results of c...

  10. Computer Simulation of a Plasma Vibrator Antenna

    Nikolay N. Bogachev; Irina L. Bogdankevich; Namik G. Gusein-zade; Vladimir P. Tarakanov


    The use of new plasma technologies in antenna technology is widely discussed nowadays. The plasma antenna must receive and transmit signals in the frequency range of a transceiver. Many experiments have been carried out with plasma antennas to transmit and receive signals. Due to lack of experimental data and because experiments are difficult to carry out, there is a need for computer (numerical) modeling to calculate the parameters and characteristics of antennas, and to verify the parameter...

  11. Circularly polarized open-loop antenna

    Li, Rong-Lin; Fusco, Vincent F.; Nakano, Hisamatsu


    A printed circular open-loop antenna is introduced as a simple structure for producing circular polarization; the antenna is fed with a coaxial probe. By introducing a gap within the circular loop a traveling-wave current is excited and thus circularly polarized radiation can be achieved. An optimized circularly polarized antenna is designed through numerical analysis using a so-called parametric method of moment technique. Experimental verification of the new antenna is presented. The antenn...


    V. Jebaraj; K.R.S. Ravi Kumar; D. Mohanageetha


    Slot antennas are often used at UHF and microwave frequencies. In slot antenna for RFID reader applications the frequency ranges from 902-923MHz to achieve circular polarization. The shapes and size of the slot, as well as the driving frequency, determine the radiation distribution pattern. The proposed compact size circularly polarized slotted microstrip antenna are summarized with design rules. The circularly polarized radiation in square patch antenna can be obtained by perturbation techni...

  13. Rectangular dielectric resonator antennas theory and design

    Yaduvanshi, Rajveer S


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

  14. Phase shift measurements for antenna systems

    Ogorodnijchuk, L. D.


    The necessity to create the high accurate antenna systems for radio systems and complexes [1] requires to provide this sphere of science and engineering with a high accurate phase-metering equipment. It's used to measure phase characteristics of units and blocks of antenna feeding systems, feeds, and antenna in the full sense [1-3], and to receive signals (phase radio direction finders, monopulse radars), and to control the operation (phase antenna arrays) as well. Also it's used for periodic...

  15. Knowledge-based antenna pattern extrapolation

    Robinson, Michael


    We describe a theoretically-motivated algorithm for extrapolation of antenna radiation patterns from a small number of measurements. This algorithm exploits constraints on the antenna's underlying design to avoid ambiguities, but is sufficiently general to address many different antenna types. A theoretical basis for the robustness of this algorithm is developed, and its performance is verified in simulation using a number of popular antenna designs.

  16. Reconfigurable Monopole Antennas With Circular Polarization

    Panahi, Afshin


    This thesis presents research on printed circularly-polarized monopole antennas and their application in reconfigurable monopole antennas. The proposed circularly-polarised monopole antennas benefit from advantages such as small size, low-cost, low-profile and simple designs. The first part of this thesis introduces three printed circularly-polarized monopole antennas for global navigation satellite systems and Wi-Fi applications. The primary focus is on the ground plane which is used as a ra...

  17. Research of Klopfenstein taper UWB monopole antenna

    Wang, Nan-Nan; Qiu, Jinghui; Zhang, Zhi-Feng; Zong, Hua; Ling-Ling, Zhong; Wei-Bo, Deng


    The tapered line theory in circuit can be applied to the design of the special-shaped monopole antenna in order to obtain better electrical characteristics. So a novel Klopfenstein taper monopole antenna is proposed. The impedance matching characteristic of the Klopfenstein tapered line is the best, and the Klopfenstein taper monopole antenna is designed based on it. On this basis, the coplanar waveguide-fed planar Klopfenstein taper monopole antennas are designed. The simulation and measurem...

  18. A novel coaxial CTS antenna design

    Qiu, Jinghui; Xing, Xiaohang; Ling-Ling, Zhong


    CTS (Continuous Transverse Stub) antenna radiates electromagnetic wave with its transverse stubs on transmission line, and its pattern in horizon plane is omnidirectional. This paper proposes a novel coaxial CTS structure, in which a monopole is applied in coaxial CTS antenna, instead of a matching load. This method may not only improve the radiation ratio, but also reduce the height of antenna. There are two stubs and a monopole composing an antenna, and the dielectric in stubs is air, which...

  19. Nested-cone transformer antenna

    Ekdahl, Carl A.


    A plurality of conical transmission lines are concentrically nested to form n output antenna for pulsed-power, radio-frequency, and microwave sources. The diverging conical conductors enable a high power input density across a bulk dielectric to be reduced below a breakdown power density at the antenna interface with the transmitting medium. The plurality of cones maintain a spacing between conductors which minimizes the generation of high order modes between the conductors. Further, the power input feeds are isolated at the input while enabling the output electromagnetic waves to add at the transmission interface. Thus, very large power signals from a pulse rf, or microwave source can be radiated.

  20. Broadband antenna arrays using planar horns

    Braude, V. B.; Sukhovetskaya, S. B.


    Broadband antennas are vitally important for various applications ranging from TV broadcasting to carrier-free ground-probing radars. We propose a microwave broadband antenna array (BAA), which may be realised using microstrip planar horns — flared end-fire radiating slot lines, known as Vivaldi-type antennas.

  1. Compact Dual-Mode Microwave Antenna

    Carr, K. L.


    Compact dual-mode antenna, 3.66 cm wide by 1.83 cm thick is used both for heating and thermographic detection of tumors in cancer research. Temperature sensor operates independently or simultaneously with heater. Antenna includes 1.6-GHz transmitter and 4.76-GHz receiver. Strip heater between antennas controls temperature of device. Maximum power output is 25 W.

  2. Isolation between three antennas at 700 MHz

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


    To address the antenna design challenges posed by many frequency bands, introduced with long-term evolution deployment, this study proposes the use of separate transmit (Tx) and receive (Rx) narrow-band antennas. In addition, a diversity Rx (Dx) antenna is needed for multiple-input multiple-output...

  3. 47 CFR 80.967 - Antenna system.


    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Antenna system. 80.967 Section 80.967... MARITIME SERVICES Radiotelephone Installation Required for Vessels on the Great Lakes § 80.967 Antenna system. The antenna must be omni-directional, vertically polarized and located as high as practicable...

  4. Antenna Construction and Propagation of Radio Waves.

    Marine Corps Inst., Washington, DC.

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

  5. 47 CFR 80.923 - Antenna system.


    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Antenna system. 80.923 Section 80.923... MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.923 Antenna system. An antenna must be provided in accordance with the applicable requirements of § 80.81 of this...

  6. 47 CFR 78.105 - Antenna systems.


    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 78.105 Section 78.105... SERVICE Technical Regulations § 78.105 Antenna systems. (a) For fixed stations operating in the 12.7-13.2... directional antennas that meet the performance standards indicated in the following table. (i) Stations...

  7. Wide-band dipole-slot antenna

    Tsaliev, T. A.


    Properties of the antenna in the form of parallel slots array cut in the flat well-conducting screen excited by symmetrical half-wave dipole are considered. On the basis of computer modeling frequency dependences of antenna input impedance, directivity and the VSWR are designed and analyzed. Results of researches evidently display advantages of such antenna.

  8. 47 CFR 74.641 - Antenna systems.


    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna systems. 74.641 Section 74.641... Stations § 74.641 Antenna systems. (a) For fixed stations operating above 2025 MHz, the following standards apply: (1) Fixed TV broadcast auxiliary stations shall use directional antennas that meet...

  9. 47 CFR 80.1017 - Antenna system.


    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Antenna system. 80.1017 Section 80.1017... MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge Act § 80.1017 Antenna system. (a) An antenna must be provided for nonportable bridge-to-bridge radiotelephone...

  10. Near Field On Chip RFID Antenna Design

    Vargas, Alberto; Vojtech, Lukas


    The process of fabricating the antenna on the top of the RFID chip eliminates the need for a separated and costly expensive process for antenna printing and assemblage, compulsory for a separated "off-chip" antenna which is much more times larger than the chip itself. This

  11. 47 CFR 74.737 - Antenna location.


    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna location. 74.737 Section 74.737... Booster Stations § 74.737 Antenna location. (a) An applicant for a new low power TV, TV translator, or TV.... (b) The transmitting antenna should be placed above growing vegetation and trees lying in...

  12. 47 CFR 73.69 - Antenna monitors.


    ... citations affecting § 73.69 see the List of CFR Sections Affected, which appears in the Finding Aids section... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna monitors. 73.69 Section 73.69... Broadcast Stations § 73.69 Antenna monitors. (a) Each station using a directional antenna must have...

  13. Numerical Study of Planar GPR Antenna Measurements

    Meincke, Peter; Hansen, Thorkild

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

  14. Future Vogues in Handset Antenna Systems

    Pelosi, Mauro; Pedersen, Gert Frølund


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

  15. Monopole Antenna with Modify Ground Plane

    kamal raj singh rajoriya; Singhal, P.K.


    This paper presents on modified the ground plane of monopole antenna with varying the shape and length. Basically the length of ground plane of monopole antenna is equal and greater than λ/4. Here analyzed a different ground plane of monopole antenna that is provided an efficient bandwidth with sufficient return loss.

  16. Monopole Antenna with Modify Ground Plane

    kamal raj singh rajoriya


    Full Text Available This paper presents on modified the ground plane of monopole antenna with varying the shape and length. Basically the length of ground plane of monopole antenna is equal and greater than λ/4. Here analyzed a different ground plane of monopole antenna that is provided an efficient bandwidth with sufficient return loss.

  17. Orthogonal antenna architecture for MIMO handsets

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


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

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

    Cappellin, Cecilia; Frandsen, Aksel; Breinbjerg, Olav


    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....

  19. Performance of Adaptive Subchannel Assignment-Based MIMO/OFDM Systems over Multipath Fading Channels


    Adaptive antenna arrays at both the base and mobile stations can further increase system capacity and improve the quality of service of conventional orthogonal frequency division multiplexing (OFDM) systems. Conventional adaptive antenna array-based multiple-input multiple-output (MIMO)/OFDM systems use the sub-carriers characterized by the largest eigenvalue to transmit the OFDM symbols. This paper describes the performance of adaptive subchannel assignment-based MIMO/OFDM systems over multipath fading channels. The system adaptively selects the eigenvectors associated with the relatively large subchannel eigenvalues to generate the antenna array weights at the base and mobile stations and then adaptively assigns the corresponding best subchannels to transmit the OFDM symbols. Simulation results show that the proposed system can achieve better performance than the conventional adaptive antenna array-based MIMO/OFDM system over multipath fading channels.

  20. On the performance of spectrum sharing systems with multiple antennas

    Yang, Liang


    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.

  1. Effect of Modulation Schemes on Performance of OFDM based Wireless Network using Smart Antenna

    Mr.Balaji G.Hogade


    Full Text Available In this paper we have presented the effect of different modulation Techniques (QPSK, 16QAM and 64QAM and number of antenna elements at the receiver (Smart Antenna on the performance of beamforming in OFDM based Wireless network. The performance of the proposedtechnique is tested for adaptive beam forming algorithm, Least Mean Square (LMS, improved LMS and conventional beamforming for different number of antenna elements. Proposed system not only has goodability of suppressing interference, but also significantly improves the bit-error rate (BERperformance of the system. Simulation results show that an adaptive beam forming gives the optimum performance on urban channels. SNR vs. BER, are compared using same set of parameters.

  2. Accurate determination of antenna directivity

    Dich, Mikael


    The derivation of a formula for accurate estimation of the total radiated power from a transmitting antenna for which the radiated power density is known in a finite number of points on the far-field sphere is presented. The main application of the formula is determination of directivity from power...

  3. Tunable Antennas for Mobile Devices

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


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

  4. Radar techniques using array antennas

    Wirth, Wulf-Dieter


    This book gives an introduction to the possibilities of radar technology based on active array antennas, giving examples of modern practical systems. There are many valuable lessons presented for designers of future high standard multifunction radar systems for military and civil applications. The book will appeal to graduate level engineers, researchers, and managers in the field of radar, aviation and space technology.

  5. The Antenna Bride and Bridegroom


    ALMA Achieves Major Milestone With Antenna-Link Success The Atacama Large Millimeter/submillimeter Array (ALMA), an international telescope project, reached a major milestone on 2 March, when two 12-m ALMA prototype antennas were first linked together as an integrated system to observe an astronomical object. "This achievement results from the integration of many state-of-the-art components from Europe and North America and bodes well for the success of ALMA in Chile", said Catherine Cesarsky, ESO's Director General. ESO PR Photo 10/07 ESO PR Photo 10/07 The Prototype Antennas The milestone achievement, technically termed 'First Fringes', came at the ALMA Test Facility (ATF), located near Socorro in New Mexico. Faint radio waves emitted by the planet Saturn were collected by two ALMA prototype antennas, then processed by new, high-tech electronics to turn the two antennas into a single, high-resolution telescope system, called an interferometer. The planet's radio emissions at a frequency of 104 gigahertz were tracked by the ALMA system for more than an hour. Such pairs of antennas are the basic building blocks of the multi-antenna imaging system ALMA. In such a system, the signals recorded by each antenna are electronically combined with the signals of every other antenna to form a multitude of pairs. Each pair contributes unique information that is used to build a highly detailed image of the astronomical object under observation. When completed in the year 2012, ALMA will have 66 antennas. "Our congratulations go to the dedicated team of scientists, engineers and technicians who produced this groundbreaking achievement for ALMA. Much hard work and many long hours went into this effort, and we appreciate it all. This team should be very proud today," said NRAO Director Fred K.Y. Lo. "With this milestone behind us, we now can proceed with increased confidence toward completing ALMA," he added. ALMA, located at an elevation of 5,000m in the Atacama Desert of

  6. Photogrammetry Of A Parabolic Antenna

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


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

  7. Installing the antenna for STELLA


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

  8. Antenna radome sample test report

    Baker, Leonard H.; Bratton, Thomas D.


    The antenna radome sample test conducted at the Federal Aviation Administration (FAA) Technical Center by the Secondary Surveillance Systems Branch, ACN-220 is documented. The test configuration consisted of the antenna radome sample centered between the Discrete Address Beacon System's (DABS) antenna and its remote Calibration Performance Monitor Equipment (CPME). The Range and Azimuth Accuracy (RAA) diagnostic program was used to determine changes in DABS performance. There were two test objectives. The first test objective was to determine if existing FAA en route radar antenna radomes would distort the signal characteristics detected by a beacon monopulse processor system. The second test objective was to determine whether this test configuration could be used to test radome samples supplied by prospective contractors in the en route radome replacement program. The RAA diagnostic program could not determine if the radome sample depicted changes in the DABS performance. It is recommended that this test procedure be abandoned due to inconclusive test results. The prospective radome manufacturers should provide the FAA with sufficient test data to confirm that it meets the requirements of the radome procurement specification.

  9. Multi-antenna synthetic aperture radar

    Wang, Wen-Qin


    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

  10. Measurement of Antenna Bore-Sight Gain

    Fortinberry, Jarrod; Shumpert, Thomas H.


    The absolute or free-field gain of a simple antenna can be approximated using standard antenna theory formulae or for a more accurate prediction, numerical methods may be employed to solve for antenna parameters including gain. Both of these methods will result in relatively reasonable estimates but in practice antenna gain is usually verified and documented via measurements and calibration. In this paper, a relatively simple and low-cost, yet effective means of determining the bore-sight free-field gain of a VHF/UHF antenna is proposed by using the Brewster angle relationship.

  11. Antenna Design for Diversity and MIMO Application

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


    efficiencies of MIMO elements would be degraded severely due to mutual couplings. In addition, the human body causes high losses on electromagnetic waves. In real applications, the presence of users may result in significant reduction of total antenna efficiencies, and the correlations of MIMO antenna systems...... are also highly affected. In this chapter, the performance of some basic MIMO antennas as well as recent technologies toimprove MIMO antenna performance of portable devices and mobile terminals are reviewed. The interactions between MIMO antennas and human body are also addressed particularly in...

  12. Forward Scattering of Loaded and Unloaded Antennas

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


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

  13. Design of broadband single polarized antenna

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


    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.

  14. Computer Simulation of a Plasma Vibrator Antenna

    Nikolay N. Bogachev


    Full Text Available The use of new plasma technologies in antenna technology is widely discussed nowadays. The plasma antenna must receive and transmit signals in the frequency range of a transceiver. Many experiments have been carried out with plasma antennas to transmit and receive signals. Due to lack of experimental data and because experiments are difficult to carry out, there is a need for computer (numerical modeling to calculate the parameters and characteristics of antennas, and to verify the parameters for future studies. Our study has modeled plasma vibrator (dipole antennas (PDA and metal vibrator (dipole antennas (MDA, and has calculated the characteristics of PDAs and MDAs in the full KARAT electro-code. The correctness of the modeling has been tested by calculating a metal antenna using the MMANA program.

  15. SKB - PNC. Development of tunnel radar antennas

    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.)

  16. New Diamond Antenna for Ultra Wideband Applications

    Ziani Kerarti Djalal


    Full Text Available There has been a flourishing prospect of UWB technology in recent years in both communication and other purposes like microwave imaging and radar applications. Recent studies of UWB antenna structures are specially concentrated on microstrip , slot and planar monopole antennas . In this work, a small monopole antenna with diamond shape of the patch (30 x 26 mm printed microstrip fed monopole antenna has been designed, some parameters like return loss (S11, Voltage Standing Wave Ratio (VSWR, radiation pattern has been performed to test the validity of simulation and verify eligibility of the antenna for the wireless communications purpose. The proposed antenna is simulated in CST Microwave Studio and has surpassed the bandwidth of UWB requirement, which is from 3.1 GHz to 10.6 GHz, and exhibits good UWB characteristics. The 10 dB return loss bandwidth of this antenna element is from 3.39 GHz to more than 14 GHz.

  17. Integrated broadband bowtie antenna on transparent substrate

    Zhang, Xingyu; Subbaraman, Harish; Zhan, Qiwen; Pan, Zeyu; Chung, Chi-jui; Yan, Hai; Chen, Ray T


    The bowtie antenna is a topic of growing interest in recent years. In this paper, we design, fabricate, and characterize a modified gold bowtie antenna integrated on a transparent glass substrate. We numerically investigate the antenna characteristics, specifically its resonant frequency and enhancement factor. We simulate the dependence of resonance frequency on bowtie geometry, and verify the simulation results through experimental investigation, by fabricating different sets of bowtie antennas on glass substrates utilizing CMOS compatible processes and measuring their resonance frequencies. Our designed bowtie antenna provides a strong broadband electric field enhancement in its feed gap. The far-field radiation pattern of the bowtie antenna is measured, and it shows dipole-like characteristics with large beam width. Such a broadband antenna will be useful for a myriad of applications, ranging from wireless communications to electromagnetic wave detection.

  18. A novel variable-distance antenna test range and high spatial resolution corroboration of the inverse square law for 433.5 MHz radiation

    de Haën, Christoph; Erhardt, Matthias


    A novel, low-budget, open-air, slant-geometry antenna test range for UHF radiation is presented. It was designed primarily to facilitate variation of the distance between emitter and receiver antennas, but has also the potential for adaptation to simultaneous variation of distance and receiver antenna orientation. In support of the validity of the range the inverse square law for 433.5 MHz radiation between two naked half-wave dipole antennas was tested with high spatial resolution from close to the far field limit outward to 46 wavelengths. Sine amplitude input voltage at the receiver antenna varied with the distance to the power -0.9970 +/- 0.0051 (R^2 = 0.992), thus corroborating the inverse square law for transmission power at the lowest frequency for which thus far data have been published. Keywords: inverse square law; dipole antenna; test facility; electromagnetic propagation; UHF measurements; distance dependence.

  19. Integration of Frequency Domain Wideband Antenna Nulling and Wavenumber Domain Image Formation for Multi-Channel SAR

    Bucciarelli, M.; D. Pastina; Cristallini, D.; M. Sedehi; Lombardo, P.


    A Multichannel Synthetic Aperture Radar (M-SAR) exploiting an antenna nulling based Electronic Counter-Counter Measures (ECCM) technique shall be able to cancel the effects of noise-like interferences over the collected SAR data. Since SAR systems often work with wide bandwidths to provide high resolution images, ECCM technique must account for the presence of wideband interference signal. In this paper we consider a wideband antenna nulling technique based on space-frequency adaptive nulling...

  20. Design and Analysis of a Multiband Koch Fractal Monopole Antenna

    Adam, Ismahayati; Soh, Ping Jack; Hadibah, R; Vandenbosch, Guy


    This work presents the design and investigation of the monopole and Koch fractal antenna. The fractal concept and geometry has been used in antenna design to obtain multi-band behavior and miniaturized size, as both of these characteristics are important requirements in current antenna design trends. The aim of this paper is to evaluate the antenna performance between monopole antenna and third iteration Koch fractal antenna. Antenna properties such as reflection coefficient (S11), bandwidth,...

  1. Multiple-Active Multiple-Passive Antenna Systems and Applications

    Tsakalaki, Elpiniki


    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......) and the active element current vector (all being functions of the variable loading). The adaptive MAMP system targets at maximizing tight MIMO ergodic and outage rate bounds, relying on partial channel knowledge when tuning to a different loading state for optimizing the rate of communication. The...... proposed 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...

  2. Antenna design and characterization based on the elementary antenna concept

    Ligthart, L. P.

    An antenna-design technique based on an elementary-antenna model (an infinitesimal pillbox structure carrying electric and magnetic currents and containing propagating TEM fields) is developed and demonstrated. An EM description of a waveguide aperture is obtained by applying approximate boundary conditions at specific points; the transmitted field is developed locally into a set of TEM field components to compute the radiation pattern; and aperture matching is achieved by calculating the aperture reflection as well. Parallel-plate, circular, and rectangular waveguides; two single-polarization TEM waveguide radiators (with and without dielectric filling); a dielectric-filled dual-polarization TE(01) waveguide radiator; and a hybrid reflector array with limited beam switching based on the TE(01) radiator are presented.

  3. Adaptive transmit selection with interference suppression

    Radaydeh, Redha Mahmoud Mesleh


    This paper studies the performance of adaptive transmit channel selection in multipath fading channels. The adaptive selection algorithms are configured for single-antenna bandwidth-efficient or power-efficient transmission with as low transmit channel estimations as possible. Due to the fact that the number of active co-channel interfering signals and their corresponding powers experience random behavior, the adaptation to channels conditions, assuming uniform buffer and traffic loading, is proposed to be jointly based on the transmit channels instantaneous signal-to-noise ratios (SNRs) and signal-to- interference-plus- noise ratios (SINRs). Two interference cancelation algorithms, which are the dominant cancelation and the less complex arbitrary cancelation, are considered, for which the receive antenna array is assumed to have small angular spread. Analytical formulation for some performance measures in addition to several processing complexity and numerical comparisons between various adaptation schemes are presented. ©2010 IEEE.

  4. Sounding Rocket Telemetry Emitter, MID Antenna and Ground Receiver Antennas

    Marque, Alexandre; Ghiotto, Anthony


    IEEE MTT-S Undergraduate Scholarships Reports The goal of this research project is to design a complete 2.45 GHz data link for telemetry application between a sounding rocket and a ground station. The emission part is embedded in the rocket and has a lot of mechanical constraints. The design for the emitter, the rocket antenna and the ground station receiver are detailed.

  5. Negative ion source with external RF antenna

    Leung, Ka-Ngo; Hahto, Sami K.; Hahto, Sari T.


    A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source. A converter can be included in the ion source to produce negative ions.

  6. Distributed antenna system and method

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


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

  7. Antenna Arrays and Automotive Applications

    Rabinovich, Victor


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

  8. 47 CFR 22.365 - Antenna structures; air navigation safety.


    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Antenna structures; air navigation safety. 22... Antenna structures; air navigation safety. Licensees that own their antenna structures must not allow these antenna structures to become a hazard to air navigation. In general, antenna structure owners...

  9. 47 CFR 73.316 - FM antenna systems.


    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false FM antenna systems. 73.316 Section 73.316... Broadcast Stations § 73.316 FM antenna systems. (a) It shall be standard to employ horizontal polarization...) Directional antennas. A directional antenna is an antenna that is designed or altered for the purpose...

  10. Planar Millimeter-Wave Antennas: A Comparative Study

    Pitra, K.; Z. Raida


    The paper describes the design and the experimental verification of three types of wideband antennas. Attention is turned to the bow-tie antenna, the Vivaldi antenna and the spiral antenna designed for the operation at millimeter waves. Bandwidth, input impedance, gain, and directivity pattern are the investigated parameters. Antennas are compared considering computer simulations in CST Microwave Studio and measured data.

  11. Tracking with all-analog adaptive antenna arrays

    Bruintjes, Thomas Maarten


    Expanding capacity requirements of wireless networks have led to spectrum scarcity. Most people will, at one point, have experienced a poor Wi-Fi connection because of too many active 2.4 GHz devices in the vicinity. Millimeter waves (especially at 60 GHz) are a promising candidate to solve this problem. In this thesis, a scenario is considered where rooms inside a building are equipped with a mm-wave radio access point connected to a fiber optical backbone. As 60 GHz does not penetrate walls...

  12. Curved spiral antennas for underwater biological applications

    Llamas, Ruben

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

  13. Stepped conical zone plate antenna

    Wiltse, James C.


    The Fresnel zone plate lens was invented and developed for optical frequencies. However, fabrication difficulties at the short optical wavelengths have prevented obtain good efficiencies. At longer microwave or millimeter-wavelengths fabrication is easier and phase correcting zone plate antennas have been used to obtain good efficiencies. This paper describes a new type of phase correcting zone plate having even better efficiency, namely a diffraction efficiency of 99 percent compared to a true lens, and an overall efficiency much better than a true lens. For the usual zone plate antenna employed at microwave or millimeter wavelengths, path length adjustment is accomplished by cutting different depths in a dielectric plate or by using two or more dielectrics having different dielectric constants. The new design uses a tilted cut in a dielectric plate, which more accurately matches the shape of a true lens and produces much lower phase error. The construction is still near and can be made for example, by a milling machine with a tilted bit. For a circular zone plate, the lens is a stepped conical or tapered shape. Because the phase steps are small, the far-field antenna pattern is excellent and sidelobe-levels are very low. Analysis of typical configurations will be given, showing that phase errors are small, lower than those for an eighth-wave corrected phase zone plate.

  14. Transcatheter Antenna For Microwave Treatment

    Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Raffoul, George W. (Inventor); Karasack, Vincent G. (Inventor); Pacifico, Antonio (Inventor); Pieper, Carl F. (Inventor)


    Method and apparatus are provided for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue to treat ventricular tachycardia and other arrhythmias while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In operation, microwave energy between about 1 Gigahertz and 12 Gigahertz is applied to monopole microwave radiation having a surface wave limiter. A test setup provides physical testing of microwave radiators to determine the temperature profile created in actual heart tissue or ersatz heart tissue. Saline solution pumped over the heart tissue with a peristaltic pump simulates blood flow. Optical temperature sensors disposed at various tissue depths within the heart tissue detect the temperature profile without creating any electromagnetic interference. The method may he used to produce a desired temperature profile in other body tissues reachable by catheter such as tumors and the like.

  15. Membrane Shell Reflector Segment Antenna

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


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

  16. Compact Miniaturized Antenna for 210 MHz RFID

    Lee, Richard Q.; Chun, Kue


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

  17. Millimeter-wave antennas configurations and applications

    du Preez, Jaco


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

  18. Compact UWB Antenna Design for MIMO Applications

    Baskaran Kasi


    Full Text Available In this study, a compact printed Multiple-Input-Multiple-Output (MIMO antenna with a dimension of 32×70 mm2 has been proposed for Ultra-Wideband (UWB systems applications. The design constitutes of two identical UWB antenna elements, which is etched onto a Taconic TLC-30 printed circuit board. The proposed antenna has been designed and simulated using computer simulation software. For validation purposes, antenna prototype is fabricated and tested. The UWB-MIMO antenna yields an impedance bandwidth of 2.9 to 12 GHz with a return loss of less than-10 dB. Furthermore, the isolation characteristic between the two antenna elements is more than 15 dB within the operating frequency range. The designed structure is found to provide good MIMO/diversity characteristic across the UWB band.

  19. Antenna design by simulation-driven optimization

    Koziel, Slawomir


    This Brief reviews a number of techniques exploiting the surrogate-based optimization concept and variable-fidelity EM simulations for efficient optimization of antenna structures. The introduction of each method is illustrated with examples of antenna design. The authors demonstrate the ways in which practitioners can obtain an optimized antenna design at the computational cost corresponding to a few high-fidelity EM simulations of the antenna structure. There is also a discussion of the selection of antenna model fidelity and its influence on performance of the surrogate-based design process. This volume is suitable for electrical engineers in academia as well as industry, antenna designers and engineers dealing with computationally-expensive design problems.

  20. Advanced microwave radiometer antenna system study

    Kummer, W. H.; Villeneuve, A. T.; Seaton, A. F.


    The practicability of a multi-frequency antenna for spaceborne microwave radiometers was considered in detail. The program consisted of a comparative study of various antenna systems, both mechanically and electronically scanned, in relation to specified design goals and desired system performance. The study involved several distinct tasks: definition of candidate antennas that are lightweight and that, at the specified frequencies of 5, 10, 18, 22, and 36 GHz, can provide conical scanning, dual linear polarization, and simultaneous multiple frequency operation; examination of various feed systems and phase-shifting techniques; detailed analysis of several key performance parameters such as beam efficiency, sidelobe level, and antenna beam footprint size; and conception of an antenna/feed system that could meet the design goals. Candidate antennas examined include phased arrays, lenses, and optical reflector systems. Mechanical, electrical, and performance characteristics of the various systems were tabulated for ease of comparison.

  1. International Mapping of Antenna-Measurement Facilities

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


    This paper presents a comprehensive international mapping of antenna-measurement facilities. This initiative, conducted within the framework of the Antenna Centre of Excellence (ACE) of the European Union, is oriented toward all institutions having research, development, or operational activities...... in the field of antenna measurements. It has been established to provide the scientific and industrial community with an efficient means to improve and facilitate their research and development activities in the field of antennas. The mapping will constitute a new service for all potential users of...... antenna measurements, in particular from the wireless communication industry, to identify and contact antenna-measurement facilities. The first phase of the mapping showed a significant and encouraging reaction to this initiative, with more than 50 European facilities currently registered. The next phase...

  2. New band-notched UWB antenna

    HE Xiao-xiang; DENG Hong-wei


    A simple and compact ultra wideband (UWB) printed monopole antenna with band-notched performance is proposed in this paper. The antenna is partially grounded so that the Q value is depressed and the impedance bandwidth is broadened. A small strip bar is loaded on each arm of the similar U-shaped radiator. The impedance bandwidth of the antenna overlap with IEEE 802.11a is rejected consequently. The geometry parameters of the antenna are investigated and optimized with HFSS. The measured bandwidth of the proposed antenna occupies about 7.89 GHz covering from 3.05 GHz to 10.94 GHz with expected notched band from 4.96 GHz to 5.98 GHz. A quasi-omnidirectional and quasi-symmetrical radiation pattern in the whole band is also obtained. As a result, a UWB wireless communication system can be simplified with the band-notched UWB antenna presented.

  3. Transmitting Antenna with Dual Circular Polarization for Indoor Antenna Measurement Range

    Mrnka, M.; Vélim, J.


    The presented paper describes design of an original transmitting antenna for specific indoor far-field measurement range. The antenna is able to generate both senses of the circular polarization with high polarization purity by using stepped septum polarizer inside a waveguide. Very high suppression of the side lobes is achieved by utilization of the higher order modes in the aperture of the final horn antenna which is directly connected to the septum polarizer. The antenna was simulated and ...

  4. Modeling of mixed-phasing antenna-plasma interactions applied to JET A2 antennas

    The use of mixed (monopole-dipole) phasing of a set of ICRF antennas is potentially useful to optimize tokamak performance and to do interesting physics experiments. However, recent mixed-phasing experiments on JET, described here, showed undesirable antenna-plasma interactions under certain circumstances. We explore a possible physical mechanism: parallel currents flowing between adjacent antennas with different phasings can lead to arcing on the antenna with the largest sheath voltage. Means of controlling the interaction are discussed

  5. Micromachined Horn Antenna Operating at 75 GHz

    Grzegorczyk, Tomasz M.; Zurcher, Jean-François; Renaud, Philippe; Mosig, Juan R.


    We propose in this paper an integrated cavity-backed horn antenna, generalizing the well-known SSFIP (Strip-Slot-Foam-Inverted Patch) design, operating at 75 GHz. The antenna was optimized using a full-wave software and realized using micromachining technologies. The proposed structure can be used for high radiation ef-ficiency antennas and arrays in the millimeter-wave band, since surface waves are inherently suppressed by the use of a metallic horn and a cavity configuration.

  6. Dual-band Omnidirectional Circularly Polarized Antenna

    Narbudowicz, Adam; Bao, Xiulong; Ammann, Max


    A dual-band omnidirectional circularly polarized antenna is proposed. The antenna comprises back-to-back microstrip patches fed by a coplanar waveguide. A very low frequency ratio of 1.182 has been achieved, which can be easily tuned by adjusting four lumped capacitors incorporated into the antenna. An analysis of the omnidirectional circular polarization mechanism as well the dual band operation is provided and confirmed by numerical and experimental data. Key parameters to tune the resonant...

  7. An antenna design for PANSAT using NEC.

    Ellrick, Daniel A.


    Approved for public release; distribution is unlimited In this thesis the Numerical Electromagnetics Code (NEC) is used to design an omnidirectional antenna for the Petite Amateur Navy Satellite (PANSAT). The completed antenna design uses a tangential turnstile antenna to achieve a circularly polarized radiation pattern with predicted worst nulls of approximately -3.0 dBi. The use of NEC-3, recently ported to 80386 personal computers, demonstrates the potential of personal computers for ...

  8. Ultrawideband antennas for microwave imaging systems

    Denidni, Tayeb A


    This book presents ultrawideband antennas and their applications on microwave imaging. The chapters focus on recent techniques, analysis, and applications along with the future vision of this emerging field of applied electromagnetics. Several emerging topics are essayed, including dielectric resonator antennas and planar ultrawideband antennas for microwave imaging.This resource incorporates modern design concepts, analysis, and optimization techniques based on recent developments. Readers are also provided with an extensive overview of current regulations, including those related to microwav

  9. Textile antenna for 50 ohm applications

    Robi Dahal; Demet Mercan; Lukas Vojtech; Marek Neruda


    The new generation of textile materials have the capability to conduct electricity and at the same time be wearable. There are much more applications involved if an antenna is made from parts that are totally wearable. This new property of conductivity in textile materials is used to implement the wireless functions to clothing. In general, the antennas are made of highly conductive metal with is a solid structure, which results in stable output. The challenge with textile antenna is output s...

  10. Vertical Meandering Approach for Antenna Size Reduction

    Li Deng; Shu-Fang Li; Ka-Leung Lau; Quan Xue


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

  11. A novel proximity coupled active integrated antenna

    Vajha, Sasidhar; Shastry, Prasad


    In this paper, a novel design approach and measured results of a compact proximity coupled active integrated antenna (PCAIA) are presented. A new type of antenna feed structure is proposed. A single self-biased (through the RF port), two-stage low noise amplifier has been integrated with a proximity coupled patch antenna having a new feed structure. The proposed approach is useful in the design of compact PCAIA with good radiation characteristics for applications in microwave wireless systems.

  12. Compact, Frequency Reconfigurable, Printed Monopole Antenna

    Ricardo Gonçalves; Pedro Pinho; Nuno B. Carvalho


    This paper proposes a possible implementation of a compact printed monopole antenna, useful to operate in UMTS and WLAN bands. In order to accomplish that, a miniaturization technique based on the application of chip inductors is used in conjunction with frequency reconfiguration capability. The chip inductors change the impedance response of the monopole, allowing to reduce the resonant frequency. In order to be able to operate the antenna in these two different frequencies, an antenna recon...

  13. A Compact Diversity Antenna for Handheld Terminals

    Hai-Lin Xiao; Zai-Ping Nie; Yu-Jing Wu


    The handheld terminals antenna should have a small size, sufficient gain and big bandwidth. In this paper, a compact planar inverted-L diversity antenna for handheld terminals is proposed. Three diversity antennas operating at 2.15 GHz are designed and the effect of important parameters of the proposed antenna is measured. The isolation is found to be better than 13 dB, the usable bandwidth is about 13%. Moreover, the measured radiation patterns are also obtained that the backward radiation is decreased.

  14. A SIW Antipodal Vivaldi Array Antenna Design

    Ying Suo; Wei Li; Jianzhong Chen


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

  15. Whip antenna design for portable rf systems

    Ponnapalli, Saila; Canora, Frank J.


    Whip type antennas are probably the most commonly used antennas in portable rf systems, such as cordless and cellular phones, rf enabled laptop computers, personal digital assistants (PDAs), and handheld computers. Whip antennas are almost always mounted on the chassis which contains the radio and other electronics. The chassis is usually a molded plastic which is coated with a conducting paint for EMI purposes. The chassis which appears as a lossy conductor to the antenna, has several effects -- detuning, altering the gain of the antenna, and shadowing its radiation pattern. Extensive modeling and measurements must be performed in order to fully characterize the affects of the chassis on the whip antenna, and to optimize antenna type, orientation and position. In many instances, modeling plays a more important role in prediction of the performance of whip antennas, since measurements become difficult due to the presence of common mode current on feed cables. In this paper models and measurements are used to discuss the optimum choice of whip antennas and the impact of the chassis on radiation characteristics. A modeling tool which has been previously described and has been successfully used to predict radiated field patterns is used for simulations, and measured and modeled results are shown.

  16. Broadband Suspended Microstrip Antenna For Circular Polarization

    Kasabegoudar, VG; Vinoy, KJ


    In this paper we propose a circularly polarized (CP) microstrip antenna on a suspended substrate with a coplanar capacitive feed and a slot within the rectangular patch. The antenna has an axial ratio bandwidth (< 3 dB) of 7.1%. The proposed antenna exhibits a much higher impedance bandwidth of about 49% (S11 < -10 dB) and also yields return loss better than -15 dB in the useful range of circular polarization. Measured characteristics of the antenna are in good agreement with the simulated re...

  17. Matching Parasitic Antenna for Single RF MIMO

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


    order to have such performance, an antenna with rich pattern modes is required by the system, thus the ESPAR antenna is investigated. The critical part on such antenna is parasitic element impedance matching. Unlike the conventional smith-chart matching method which assumes the minimal resistance is...... zero and with goal of 50 ohm or 75 ohm matching, matching on such parasitic antenna will adopt negative value as well. This paper presents a matching network with controllable impedance even to the range of negative values....

  18. Handbook of smart antennas for RFID systems


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

  19. Flexible Microstrip Antenna for Skin Contact Application

    Sudhir Shrestha; Mangilal Agarwal; Parvin Ghane; Kody Varahramyan


    Microstrip antennas are finding a growing medical application in imaging, diagnosis, and treatment. This paper presents a flexible microstrip antenna that can be placed in contact with the human skin. The developed antenna is only 0.25 mm thick, has 32 mm × 31 mm dimensions, and −19 dB measured | 1 1 | parameter at 2.45 GHz. A specific application of the antenna in microwave breast imaging is considered. Analytical results using simulation models and experimental results using skin phantoms...

  20. Thermal Loss in High-Q Antennas

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


    Tunable antennas are very promising for future generations of mobile communications, where antennas are required to cover a wide range operating bands. This letter aims at characterizing the loss mechanism of tunable antennas. Tunable antennas typically exhibit a high Quality factor (Q), which can...... lead to thermal loss due to the conductivity of the metal. The investigation shows that copper loss is non-negligible for high Q values. In the proposed design the copper loss is 2 dB, for a Q of 260 at 700 MHz....

  1. Analysis on two novel spherical helical antennas

    Hou ZHANG; Yingzeng YIN; Dongyu XIA


    Two novel spherical helical antennas are designed by projecting the planar equiangular spiral antenna onto hemisphere and partial sphere surfaces.Their radiation properties are analyzed by the moment method with curved basis and test function,and the curves of the voltage standing wave ratio (VSWR),gain,polarization and pattern that change with frequency are also given,respectively.It can be seen that the circular polarization band of the novel hemispherical helical antenna is broader.The gain curve of the partial spherical helical antenna is flatter and the structure is simpler.

  2. Novel Electrically Small Spherical Electric Dipole Antenna

    Kim, Oleksiy S.


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

  3. Resonance spectra of diabolo optical antenna arrays

    Guo, Hong; Guo, Junpeng, E-mail: [Department of Electrical and Computer Engineering, University of Alabama in Huntsville, 301 Sparkman Drive, Huntsville, AL 35899 (United States); Simpkins, Blake; Caldwell, Joshua D. [Naval Research Laboratory, 4555 Overlook Ave., SW Washington, DC 20375 (United States)


    A complete set of diabolo optical antenna arrays with different waist widths and periods was fabricated on a sapphire substrate by using a standard e-beam lithography and lift-off process. Fabricated diabolo optical antenna arrays were characterized by measuring the transmittance and reflectance with a microscope-coupled FTIR spectrometer. It was found experimentally that reducing the waist width significantly shifts the resonance to longer wavelength and narrowing the waist of the antennas is more effective than increasing the period of the array for tuning the resonance wavelength. Also it is found that the magnetic field enhancement near the antenna waist is correlated to the shift of the resonance wavelength.

  4. Switchable Electromagnetic Bandgap Surface Wave Antenna

    Qiang Bai


    Full Text Available This paper presents a novel switchable electromagnetic bandgap surface wave antenna that can support both a surface wave and normal mode radiation for communications at 2.45 GHz. In the surface wave mode, the antenna has a monopole-like radiation pattern with a measured gain of 4.4 dBi at ±49° and a null on boresight. In the normal mode, the antenna operates like a back-fed microstrip patch antenna.

  5. Wideband Monopole Antenna for WLAN Applications

    Muhammad Umar


    Full Text Available This paper presents a circular patch antenna for WLAN applications with wideband characteristics. It is shown that impedance of the antenna is matched over wideband by using the partial ground plane and quarter wave transformer with slotted TX-Line. Ansoft HFSS is used for simulation tool to map the numerical results for the return loss frequency behavior of antenna. Measure of bandwidth, return loss and radiation pattern are also reported with satisfactory performance. As the patch is circular in shape so substrate is kept in the same shape. The shape of the substrate is also discussed in details for specific antenna designs.

  6. A Design of Double Broadband MIMO Antenna

    Yanfeng Geng


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

  7. VAlidation STandard antennas: Past, present and future

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


    The field of antenna measurements is lacking a Golden Standard, i.e. an antenna of which the pattern is known by definition. To gain confidence in the performance of a range, including the procedures and skills of the operators, range comparison has been a popular tool for over three decades. In......, specifically designed for validation campaigns of antenna measurement ranges. The driving requirements of VAST antennas are their mechanical stability over a given operational temperature range and with respect to any orientation of the gravity field. The mechanical design shall ensure extremely stable...

  8. Mathcad computer applications predicting antenna parameters from antenna physical dimensions and ground characteristics

    Gerry, Donald D.


    Approved for public release; distribution is unlimited. This report provides the documentation for a set of computer applications for the evaluation of antenna parameters. The applications are written for the Mathcad personal computer software for various antenna types listed in the thesis index. Antenna dimen Lieutenant Commander, United States Navy

  9. TOLPA (Tripod Omnidirectional Low Profile Antenna): a vertically polarized antenna with 90% bandwidth

    Zürcher, J.-F.


    A new vertically polarized omnidirectional antenna, inspired by an old design, has been studied, optimized, realized and measured. With a radiation pattern similar to the classical monopole on a ground plane, the proposed antenna concept provides a much larger bandwidth and a very low profile. This antenna has numerous potential applications for mobile communications, UWB and others.

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

    Bakr, Omar


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

  11. A telemetry antenna system for unmanned air vehicles

    DOĞAN, Mustafa; Dogan, Mustafa; Üstüner, Fatih; Ustuner, Fatih


    This paper presents a low VSWR high gain telemetry antenna system manufactured for UAVs that provides 360± coverage in the roll plane of the UAV. Proposed telemetry antenna system includes four telemetry antennas, one power divider that has one input and four output terminals which feeds the telemetry antennas with equal magnitude and phase. Proposed high gain telemetry antennas are based on the feeding of the microstrip patch antenna via aperture coupling. Full coverage in the roll plane of ...

  12. Improved patch antenna performance by using a metamaterial cover

    ZHU Fang-ming; HU Jun


    A new patch antenna system with a metamaterial cover is presented in this paper. The impedance, radiation pattern, and directivity of such an antenna are studied. A performance comparison between the conventional patch antenna and the new metamaterial patch antenna is given. The results show that the directivity of the metamaterial patch antenna is significantly improved. The effect of the metamaterial cover's layer numbers on the radiation pattern of the patch antenna is also studied.

  13. CPW-Fed Ring Antenna For UWB Applications

    Sheetal Kamboj; Amit Kumar


    This paper presents a Coplanar waveguide feed ( CPW) monopole ring antenna for ultra wideband applications. The proposed antenna consist of ring type patch embedded with horizontal strip in the patch. The parametric study is performed to understand the characteristics of the proposed antenna. The antenna exhibits impedance bandwidth from 3.7 GHz to 10.7 GHz. The various antenna parameters are studied. The proposed antenna is suitable for UWB applications.

  14. Magnetic antenna excitation of whistler modes. IV. Receiving antennas and reciprocity

    Antenna radiation patterns are an important property of antennas. Reciprocity holds in free space and the radiation patterns for exciting and receiving antennas are the same. In anisotropic plasmas, radiation patterns are complicated by the fact that group and phase velocities differ and certain wave properties like helicity depend on the direction of wave propagation with respect to the background magnetic field B0. Interference and wave focusing effects are different than in free space. Reciprocity does not necessarily hold in a magnetized plasma. The present work considers the properties of various magnetic antennas used for receiving whistler modes. It is based on experimental data from exciting low frequency whistler modes in a large uniform laboratory plasma. By superposition of linear waves from different antennas, the radiation patterns of antenna arrays are derived. Plane waves are generated and used to determine receiving radiation patterns of different receiving antennas. Antenna arrays have radiation patterns with narrow lobes, whose angular position can be varied by physical rotation or electronic phase shifting. Reciprocity applies to broadside antenna arrays but not to end fire arrays which can have asymmetric lobes with respect to B0. The effect of a relative motion between an antenna and the plasma has been modeled by the propagation of a short wave packet moving along a linear antenna array. An antenna moving across B0 has a radiation pattern characterized by an oscillatory “whistler wing.” A receiving antenna in motion can detect any plane wave within the group velocity resonance cone. The radiation pattern also depends on loop size relative to the wavelength. Motional effects prevent reciprocity. The concept of the radiation pattern loses its significance for wave packets since the received signal does not only depend on the antenna but also on the properties of the wave packet. The present results are of fundamental interest and of

  15. Apparatus and methods for packaging integrated circuit chips with antenna modules providing closed electromagnetic environment for integrated antennas

    Gaucher, Brian P. (Inventor); Grzyb, Janusz (Inventor); Liu, Duixian (Inventor); Pfeiffer, Ullrich R. (Inventor)


    Apparatus and methods are provided for packaging IC chips together with integrated antenna modules designed to provide a closed EM (electromagnetic) environment for antenna radiators, thereby allowing antennas to be designed independent from the packaging technology.

  16. Breadboard Signal Processor for Arraying DSN Antennas

    Jongeling, Andre; Sigman, Elliott; Chandra, Kumar; Trinh, Joseph; Soriano, Melissa; Navarro, Robert; Rogstad, Stephen; Goodhart, Charles; Proctor, Robert; Jourdan, Michael; Rayhrer, Benno


    A recently developed breadboard version of an advanced signal processor for arraying many antennas in NASA s Deep Space Network (DSN) can accept inputs in a 500-MHz-wide frequency band from six antennas. The next breadboard version is expected to accept inputs from 16 antennas, and a following developed version is expected to be designed according to an architecture that will be scalable to accept inputs from as many as 400 antennas. These and similar signal processors could also be used for combining multiple wide-band signals in non-DSN applications, including very-long-baseline interferometry and telecommunications. This signal processor performs functions of a wide-band FX correlator and a beam-forming signal combiner. [The term "FX" signifies that the digital samples of two given signals are fast Fourier transformed (F), then the fast Fourier transforms of the two signals are multiplied (X) prior to accumulation.] In this processor, the signals from the various antennas are broken up into channels in the frequency domain (see figure). In each frequency channel, the data from each antenna are correlated against the data from each other antenna; this is done for all antenna baselines (that is, for all antenna pairs). The results of the correlations are used to obtain calibration data to align the antenna signals in both phase and delay. Data from the various antenna frequency channels are also combined and calibration corrections are applied. The frequency-domain data thus combined are then synthesized back to the time domain for passing on to a telemetry receiver

  17. Reception of Multiple Telemetry Signals via One Dish Antenna

    Mukai, Ryan; Vilnrotter, Victor


    A microwave aeronautical-telemetry receiver system includes an antenna comprising a seven-element planar array of receiving feed horns centered at the focal point of a paraboloidal dish reflector that is nominally aimed at a single aircraft or at multiple aircraft flying in formation. Through digital processing of the signals received by the seven feed horns, the system implements a method of enhanced cancellation of interference, such that it becomes possible to receive telemetry signals in the same frequency channel simultaneously from either or both of two aircraft at slightly different angular positions within the field of view of the antenna, even in the presence of multipath propagation. The present system is an advanced version of the system described in Spatio- Temporal Equalizer for a Receiving-Antenna Feed Array NPO-43077, NASA Tech Briefs, Vol. 34, No. 2 (February 2010), page 32. To recapitulate: The radio-frequency telemetry signals received by the seven elements of the array are digitized, converted to complex baseband form, and sent to a spatio-temporal equalizer that consists mostly of a bank of seven adaptive finite-impulse-response (FIR) filters (one for each element in the array) plus a unit that sums the outputs of the filters. The combination of the spatial diversity of the feedhorn array and the temporal diversity of the filter bank affords better multipath suppression performance than is achievable by means of temporal equalization alone. The FIR filter bank adapts itself in real time to enable reception of telemetry at a low bit error rate, even in the presence of frequency-selective multipath propagation like that commonly found at flight-test ranges. The combination of the array and the filter bank makes it possible to constructively add multipath incoming signals to the corresponding directly arriving signals, thereby enabling reductions in telemetry bit-error rates.

  18. Enabling Technologies for Fabrication of Large Area Flexible Antennas Project

    National Aeronautics and Space Administration — Flexible, foldable, and/or inflatable antenna systems open up a wealth of opportunities. Integrating antenna elements and related electronics onto flexible...

  19. Micro strip Patch Antenna and its Applications: a Survey

    Indrasen Singh


    Full Text Available The study of microstrip patch antennas has made great progress in recent years. Compared with conventional antennas, microstrip patch antennas have more advantages and better prospects. They are lighter in weight, low volume, low cost, low profile, smaller in dimension and ease of fabrication and conformity. Moreover, the microstrip patch antennas can provide dual and circular polarizations, dual-frequency operation, frequency agility, broad band-width, feedline flexibility, beam scanning omnidirectional patterning. In this paper we discuss the microstrip antenna, types of microstrip antenna, feeding techniques and application of microstrip patch antenna with their advantage and disadvantages over conventional microwave antennas.

  20. Quantized Multimode Precoding in Spatially Correlated Multi-Antenna Channels

    Raghavan, Vasanthan; Sayeed, Akbar


    Multimode precoding, where the number of independent data-streams is adapted optimally, can be used to maximize the achievable throughput in multi-antenna communication systems. Motivated by standardization efforts embraced by the industry, the focus of this work is on systematic precoder design with realistic assumptions on the spatial correlation, channel state information (CSI) at the transmitter and the receiver, and implementation complexity. For spatial correlation of the channel matrix, we assume a general channel model, based on physical principles, that has been verified by many recent measurement campaigns. We also assume a coherent receiver and knowledge of the spatial statistics at the transmitter along with the presence of an ideal, low-rate feedback link from the receiver to the transmitter. The reverse link is used for codebook-index feedback and the goal of this work is to construct precoder codebooks, adaptable in response to the statistical information, such that the achievable throughput is...

  1. Reconfigurable Antenna and Cognitive Radio for Space Applications

    Hwu, Shian U.


    This presentation briefly discusses a research effort on mitigation techniques of radio frequency interference (RFI) on communication systems for possible space applications. This problem is of considerable interest in the context of providing reliable communications to the space vehicle which might suffer severe performance degradation due to RFI sources such as visiting spacecrafts and various ground radar systems. This study proposes a communication system with Reconfigurable Antenna (RA) and Cognitive Radio (CR) to mitigate the RFI impact. A cognitive radio is an intelligent radio that is able to learn from the environment and adapt to the variations in its surrounding by adjusting the transmit power, carrier frequency, modulation strategy or transmission data rate. Therefore, the main objective of a cognitive radio system is to ensure highly reliable communication whenever and wherever needed. To match the intelligent adaptability of the cognitive radio, a reconfigurable antenna system will be required to ensure the system performance. The technical challenges in design such a system will be discussed in this presentation.

  2. Experimental application of QCD antennas

    A serious problem in searches for new physics at the LHC is the rejection of QCD induced multijet events. In this thesis the formalism of QCD antenna variables based on the SPHEL approximation of QCD matrix elements is applied for the rst time on experimentally reconstructed jets in order to discriminate QCD from supersymmetric processes. The new observables provide additional information with respect to traditional event shape variables. Albeit correlated with experimentally measured missing transverse energy, the variables can be used to improve the signal to background ratio. (orig.)

  3. Experimental application of QCD antennas

    Bobrovskyi, Sergei


    A serious problem in searches for new physics at the LHC is the rejection of QCD induced multijet events. In this thesis the formalism of QCD antenna variables based on the SPHEL approximation of QCD matrix elements is applied for the rst time on experimentally reconstructed jets in order to discriminate QCD from supersymmetric processes. The new observables provide additional information with respect to traditional event shape variables. Albeit correlated with experimentally measured missing transverse energy, the variables can be used to improve the signal to background ratio. (orig.)

  4. Ultrawideband antennas design and applications

    Valderas, Daniel; Puente, David


    Ultrawideband (UWB) technology, positioned as the cutting edge of research and development, paves the way to meet the emerging demands set by broadband wireless applications, such as high-speed data transmission, medical imaging, short-range radars, electromagnetic testing, etc. This breathtaking resource builds upon the basics of UWB technology to provide a complete compilation of figures of merit along with a vital state-of-the-art of the different antenna alternatives that are to be employed according to the specific application. Without excessive recourse to mathematics, this volume emphas

  5. HF spectrum occupancy and antennas

    Yurdanur Tulunay; Yildirim Bahadirlar; Ersin Tulunay; Haris Haralambous; Lefteris Economou; Joaquim Azevedo; António Casimiro; A. Serdar Türk; E. Michael Warrington


    This paper deals with the research made during the COST 296 action in the WG2, WP 2.3 in the antennas and

    HF spectrum management fields, focusing the Mitigation of Ionospheric Effects on Radio Systems as the subject of this COST action.

  6. Solar energy collection by antennas

    Corkish, R.; Green, M.A.; Puzzer, T. [University of New South Wales, Sydney (Australia). Centre for Advanced Silicon Photovoltaics and Photonics


    The idea of collecting solar electromagnetic radiation with antenna-rectifier (rectenna) structures was proposed three decades ago but has not yet been achieved. The idea has been promoted as having potential to achieve efficiency approaching 100% but thermodynamic considerations imply a lower limit of 85.4% for a non-frequency-selective rectenna and 86.8% for one with infinite selectivity, assuming maximal concentration in each case. This paper reviews the history and technical context of solar rectennas and discusses the major issues: thermodynamic efficiency limits, rectifier operation at optical frequencies, harmonics production and electrical noise. (author)

  7. Miniaturization of Spherical Magnetodielectric Antennas

    Hansen, Troels Vejle

    ; Arbitrary order of the spherical wave, arbitrary radius of the spherical antenna, as well as arbitrarily large core permeability and/or permittivity, given an inversely proportional frequency variation of the imaginary part(s) and an arbitrary dispersion of the real part(s) - thus describing both lossless...... of the emerging and huge demand for an increasing number of ever smaller mobile communication devices. The classical investigations of fundamental ESA performance limitations are usually formulated in terms of a lower bound upon the radiation quality factor Q, because for ESAs, Q is directly related...

  8. Microwave Tomographic Imaging Utilizing Low-Profile, Rotating, Right Angle-Bent Monopole Antennas

    N. R. Epstein


    Full Text Available We have developed a simple mechanism incorporating feedline bends and rotary joints to enable motion of a monopole antenna within a liquid-based illumination chamber for tomographic imaging. The monopole is particularly well suited for this scenario because of its small size and simplicity. For the application presented here a full set of measurement data is collected from most illumination and receive directions utilizing only a pair of antennas configured with the rotating fixture underneath the imaging tank. Alternatively, the concept can be adapted for feed structures entering the tank from the sides to allow for measurements with vertically and horizontally polarized antennas. This opens the door for more advanced imaging applications where anisotropy could play an important role such as in bone imaging.

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

    R. Seller


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

  10. Juno Microwave Radiometer Patch Array Antennas

    Chamberlain, N.; Chen, J.; Focardi, P.; Hodges, R.; Hughes, R.; Jakoboski, J.; Venkatesan, J.; Zawadzki, M.


    Juno is a mission in the NASA New Frontiers Program with the goal of significantly improving our understanding of the formation and structure of Jupiter. This paper discusses the modeling and measurement of the two patch array antennas. An overview of the antenna architecture, design and development at JPL is provided, along with estimates of performance and the results of measurements.

  11. Antenna Design Exploiting the Duplex Isolation

    Barrio, Samantha Caporal Del; Pedersen, Gert Frølund


    A novel design addressing the antenna bandwidth issue for future communication standards on handsets is presented. It consists of a tunableantenna- pair for operation with a tunable front-end. The antennas are narrow-band and frequency-reconfigurable. This Letter focuses on the low communication ...

  12. Koch-Fractal Yagi-Uda Antenna

    Teisbæk, Henrik Bjørn; Jakobsen, Kaj Bjarne


    A Yagi-Uda antenna constructed of three Koch fractal elements is presented. Simulated and measured characteristics of the antenna shows a half-power beam-width of 64◦ achieved with dimensions below a third of a wavelength. Furthermore, the Koch dipole and its size miniaturization capabilities are...

  13. 38 GHz Antennas on Micromachined Silicon Substrates.

    Marcelli, Romolo; Dragoman, M.; Neculoiu, Dan; Giacomozzi, Flavio; Muller, Alexandru; Nitescu, N.


    A new configuration of a double folded double slot CPW feed micromachined antenna array was realized on a 1.5 µm thin three-layer dielectric membrane fabricated on a silicon substrate. The antenna was designed for an operating frequency of 38 GHz, and the double folded configuration was used for minimizing the membrane extension.

  14. Slotted waveguide antennas for practical radar systems

    Sekretarov, S. S.; Vavriv, D. M.


    This article summarizes recent results on the development, fabrication, and application of slotted waveguide antenna systems for practical radar systems, including Ka-band helicopter collision avoidance and weather radar, Ku-band surveillance and tracking radar, and X-band airborne SAR system. The corresponding design solutions, antenna characteristics, and test results are presented and discussed.

  15. 47 CFR 74.1237 - Antenna location.


    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Antenna location. 74.1237 Section 74.1237... FM Broadcast Booster Stations § 74.1237 Antenna location. (a) An applicant for a new station to be... at which there is available a suitable signal from the primary station. The transmitting...

  16. Multiple Antennas Arm Effective MIMO Systems

    Thaysen, Jesper; Jakobsen, Kaj Bjarne


    Understanding the interactions among different combinations of receive and transmit antenna elements can help increase the capacity of cellular wireless systems.......Understanding the interactions among different combinations of receive and transmit antenna elements can help increase the capacity of cellular wireless systems....

  17. Miniaturization of UWB Antennas on Organic Material

    Symeon Nikolaou


    Full Text Available Three planar, CPW-fed, UWB antennas with increasingly reduced size are presented and the miniaturization method is discussed. The first antenna is a CPW-fed elliptical slot with an uneven U-shaped tuning stub, the second antenna is a cactus shaped monopole, and the third one is a miniaturized version of the cactus shaped monopole antenna. All presented antennas have a simulated and measured return loss below −10 dB over the 3.1 to 10.6 GHz UWB frequency range and mostly omnidirectional radiation patterns. The proposed antennas are fabricated on liquid crystal polymer (LCP. The CPW-fed slot antenna requires an overall board dimension of 38 mm × 40 mm, and the evolved cactus monopole is confined in a 28 mm × 32 mm board, while the final miniaturized cactus monopole is printed on 28 mm × 20 mm board, resulting in a 41% and 63% size reduction, respectively. Using both simulations and measurements, the paper analyzes the response of all three antennas and discusses and demonstrates the effectiveness of the implemented miniaturization method.

  18. Compact Spiral Loaded Printed Monopole Antenna

    Bao, Xiulong; Ammann, Max


    A novel miniaturized printed monopole structure is proposed. The antenna comprises a printed monopole strip which is loaded by a spiral located on the rearside connected by a via. The inductive loading provided by the spiral enables considerable miniaturization of antenna. A parametric study of key dimensional parameters and groundplane are discussed.

  19. Omnidirectional, circularly polarized, cylindrical microstrip antenna

    Stanton, Philip H. (Inventor)


    A microstrip cylindrical antenna comprised of two concentric subelements on a ground cylinder, a vertically polarized (E-field parallel to the axis of the antenna cylinder) subelement on the inside and a horizontally polarized (E-field perpendicular to the axis) subelement on the outside. The vertical subelement is a wraparound microstrip radiator. A Y-shaped microstrip patch configuration is used for the horizontally polarized radiator that is wrapped 1.5 times to provide radiating edges on opposite sides of the cylindrical antenna for improved azimuthal pattern uniformity. When these subelements are so fed that their far fields are equal in amplitude and phased from each other, a circularly polarized EM wave results. By stacking a plurality of like antenna elements on the ground cylinder, a linear phased array antenna is provided that can be beam steered to the desired elevation angle.

  20. A simple EHF hemispheric coverage antenna

    Lee, J. C.


    A circulary polarized, axially symmetric, wide-beam radiator is required in many applications, including TT&C for UAV's and satellites. This report discusses some existing wide-beam antenna designs including divergent lenses and reflectors and introduces a new antenna design. Using a simple dielectric ring in conjunction with a dielectric loaded circular waveguide opening, a near ideal, axially symmetric, hemispheric coverage antenna with circular polarization of good axial ratio and wide-band impedance match is realized. Mechanically, the antenna is small, lightweight, and low cost. The dielectric used is the common Rexolite. Since no lossy materials or resonant scatterers are used, the antenna performance is inherently broadband and low loss. A K sub a-band prototype as well as compact designs for both Q- and K-bands are described.

  1. A Microstripe Slotted Patch Antenna Using Amc

    Manju Saini,


    Full Text Available Microstrip patch antenna offer an attractive solution to compact and ease-low-cost design of modern wireless communication system due to their many advantages as light weight and low volume, low profile, planer configuration which can be easily made conformal to low fabrication cost and capability of obtaining dual and triple frequency operations. A microstrip patch antenna with bandwidth enhancement by means of artificial magnetic conductor (AMC/electromagnetic band-gap structure (EBG is studied in this paper. The three different geometry shapes, the U, E and H are developed from rectangular patch. The antennas studied in this paper are simulated using sonnet software and results compared with the conventional rectangular patch antenna. The results obtained clearly shows that , bandwidth of conventional rectangular microstrip antenna can be enhanced has been studied

  2. Miniaturized Planar Split-Ring Resonator Antenna

    Kim, Oleksiy S.; Breinbjerg, Olav


    A miniaturized planar antenna based on a broadside-coupled split ring resonator excited by an arc-shaped dipole is presented. The excitation dipole acts as a small tuning capacitor in series with a parallel RLC circuit represented by the SRR. The antenna resonance frequency and dimensions a...... essentially determined by the SRR, while by varying the dipole arm length the input resistance is changed in a wide range, thus matching the antenna to a feed line and compensating for simulation and manufacturing inaccuracies. No additional matching network is required. Theoretically, there is no limit on...... subsequently tuned to 50 ohms simply by cutting out the excessive arm length. This tuning technique is especially useful in practical applications, since it allows the antenna to be tuned in-place and thereby compensate for various inaccuracies as well as for an antenna environment....

  3. Structurally Integrated Antenna Concepts for HALE UAVs

    Cravey, Robin L.; Vedeler, Erik; Goins, Larry; Young, W. Robert; Lawrence, Roland W.


    This technical memorandum describes work done in support of the Multifunctional Structures and Materials Team under the Vehicle Systems Program's ITAS (Integrated Tailored Aero Structures) Project during FY 2005. The Electromagnetics and Sensors Branch (ESB) developed three ultra lightweight antenna concepts compatible with HALE UAVs (High Altitude Long Endurance Unmanned Aerial Vehicles). ESB also developed antenna elements that minimize the interaction between elements and the vehicle to minimize the impact of wing flexure on the EM (electromagnetic) performance of the integrated array. In addition, computer models were developed to perform phase correction for antenna arrays whose elements are moving relative to each other due to wing deformations expected in HALE vehicle concepts. Development of lightweight, conformal or structurally integrated antenna elements and compensating for the impact of a lightweight, flexible structure on a large antenna array are important steps in the realization of HALE UAVs for microwave applications such as passive remote sensing and communications.

  4. Textile UWB Antenna Bending and Wet Performances

    Mai A. R. Osman


    Full Text Available The vision and ideas of wearable computing systems describe future electronic systems as an integral part of our everyday clothing that provides the wearer with such intelligent personal assistants. Recently, there has been growing interest in the antenna community to merge between wearable systems technology, ultrawideband (UWB technology and textile technology. This work aimed to make closer steps towards real wearability by investigating the possibilities of designing wearable UWB antenna where textile materials are used for the substrate as well as the conducting parts of the designed antenna. Two types of conducting materials have been used for conducting parts, while a nonconducting fabric has been used as antenna substrate material. A set of comparative results of the proposed design were presented and discussed. Moreover, effects on the return loss by means of measurements for each fabricated antenna prototype under bent and fully wet conditions were discussed in more details.


    Xia Dongyu; Zhang Hou; Wang Chong; Zhang Qianyue


    A novel ellipsoidal helical antenna is proposed and studied in this letter.As a special instance,the hemispherical helical antennas are analyzed firstly,which indicates that the characteristics of a two-arm unit are better than that of a single-arm unit.Based on this,the ellipsoidal helical antenna,formed by changing the axial direction's dimension of the two-arm hemispherical helical antenna,is analyzed by the moment method with curved basic and testing function.The effects to VSWR (Voltage Standing Wave Ratio),gain,polarization and patterns by the axial direction's dimensions are investigated.The study results provide dependable gist to the choice of antenna format according to the practical requirements.




    Full Text Available The emerging techniques in the medical field include the use of bio implantable antennas to diagnose the diseases. The major disadvantage of these techniques is the side-effects caused by the radiations in the human body. There have been a lot of advancements in this area to reduce the radiation emitted. One among them is the use of PIFA antenna inside an indestructible capsule (Polyetheretherketones which is helpful in both short and long range communications. The workincludes the design of PIFA antenna using IE3D and MATLAB software. The characteristics of the antenna are analyzed with the aim to reduce the size and radiation effect of antenna and to increase thegain, efficiency and data rate.


    Leong Kah Meng


    Full Text Available This study presents a concept on wireless energy transmission using microstrip antenna pairs. Microstrip antenna is chosen in its implementation in wireless energy transfer application primarily due to its characteristics: Its ease of analysis, fabrication and their attractive radiation characteristics. The outcome of this research is the fabrication of two microstrip antennas with resonant frequency of 1.94 GHz and 2.5 GHz respectively. The performance and the power gain for each of microstrip antennas which act as the transmitter and receiver respectively were evaluated within certain distance. The limitations of the experiment as well as the possible solutions in increasing system efficiency are being discussed. Experiment shows that the microstrip antenna with a lower resonant frequency performs better in long distance wireless energy transmission.

  8. Super wideband characteristics of monopolar patch antenna

    Xi Chen


    Full Text Available A simple method of acquiring super wideband characteristics for monopolar patch antenna is proposed. Through adopting a modified cone as feeding and radiating structure, the monopolar patch antenna can reach the impedance bandwidth of more than 1:23.4 for voltage standing wave ratio (VSWR ≤ 2. In the whole operating band, the antenna has the like-monopole omnidirectional radiation patterns and the peak gains of 3.8–8.7 dB. Meanwhile, the height of the antenna is just 0.074λ(c, and the diameter of the radiated body is 0.205λ(c, which is smaller than other ultra-wideband omnidirectional antenna.

  9. Evolutionary Optimization of Yagi-Uda Antennas

    Lohn, Jason D.; Kraus, William F.; Linden, Derek S.; Colombano, Silvano P.


    Yagi-Uda antennas are known to be difficult to design and optimize due to their sensitivity at high gain, and the inclusion of numerous parasitic elements. We present a genetic algorithm-based automated antenna optimization system that uses a fixed Yagi-Uda topology and a byte-encoded antenna representation. The fitness calculation allows the implicit relationship between power gain and sidelobe/backlobe loss to emerge naturally, a technique that is less complex than previous approaches. The genetic operators used are also simpler. Our results include Yagi-Uda antennas that have excellent bandwidth and gain properties with very good impedance characteristics. Results exceeded previous Yagi-Uda antennas produced via evolutionary algorithms by at least 7.8% in mainlobe gain. We also present encouraging preliminary results where a coevolutionary genetic algorithm is used.

  10. Telecommunications Antennas for the Juno Mission to Jupiter

    Vacchione, Joseph D.; Kruid, Ronald C.; Prata, Aluizio, Jr.; Amaro, Luis R.; Mittskus, Anthony P.


    The Juno Mission to Jupiter requires a full sphere of coverage throughout its cruise to and mission at Jupiter. This coverage is accommodated through the use of five (5) antennas; forward facing low gain, medium gain, and high gain antennas, and an aft facing low gain antenna along with an aft mounted low gain antenna with a torus shaped antenna pattern. Three of the antennas (the forward low and medium gain antennas) are classical designs that have been employed on several prior NASA missions. Two of the antennas employ new technology developed to meet the Juno mission requirements. The new technology developed for the low gain with torus shaped radiation pattern represents a significant evolution of the bicone antenna. The high gain antenna employs a specialized surface shaping designed to broaden the antenna's main beam at Ka-band to ease the requirements on the spacecraft's attitude control system.

  11. Adaptive beamforming and phase bias compensation for GNSS receiver

    Hongwei Zhao; Baowang Lian; Juan Feng


    Adaptive antenna arrays have been used to mitigate the interference on global navigation satel ite system (GNSS) re-ceivers. The performance of interference mitigation depends on the beamforming algorithms adopted by the antenna array. However, the adaptive beamforming wil change the array pattern in real-time, which has the potential to introduce phase center biases into the antenna array. For precise applications, these phase biases must be mitigated or compensated because they wil bring errors in code phase and carrier phase measurements. A novel adaptive beamforming algorithm is proposed firstly, then the phase bias induced by the proposed algorithm is estimated, and final y a com-pensation strategy is addressed. Simulations demonstrate that the proposed beamforming algorithm suppresses effectively the strong interference and improves significantly the capturing performance of GNSS signals. Simultaneously, the bias compensation method avoids the loss of the carrier phase lock and reduces the phase measurement errors for GNSS receivers.

  12. Robust adaptive beamforming for MIMO monopulse radar

    Rowe, William; Ström, Marie; Li, Jian; Stoica, Petre


    Researchers have recently proposed a widely separated multiple-input multiple-output (MIMO) radar using monopulse angle estimation techniques for target tracking. The widely separated antennas provide improved tracking performance by mitigating complex target radar cross-section fades and angle scintillation. An adaptive array is necessary in this paradigm because the direct path from any transmitter could act as a jammer at a receiver. When the target-free covariance matrix is not available, it is critical to include robustness into the adaptive beamformer weights. This work explores methods of robust adaptive monopulse beamforming techniques for MIMO tracking radar.

  13. Enhancement of Antenna Performance for Data Transmission

    In remote radiation measurements that are being developed at the Department of Engineering Physics, Faculty of Engineering Gadjah Mada University, has constraints on the quality of its communications system. The problem that needs to be resolved is on antenna system. Optimum antenna performance, potentially increase effectively telecommunication quality, and minimizing error in data communication system. In every antenna parameter measurement that used in this research, the conclusion is antenna that tuned in 141.6 MHz frequency (A state) is more better than it tuned in 145.6 MHz frequency (B state). Antenna in A state can reach value of ρ at least 0.01 the return-loss measured at 53.98 dB and field strength meter show 1.95 volt. It compared with B state antenna, where it has ρ value at least only can reach 0.19 then return-loss measured only at 20.44 dB and the measuring by field strength meter only 1.2 volts in the same range with A state antenna. In this research, the same antenna is tuned in every frequency, but the maximum result has reached in antenna that tuned in 141.6 MHz frequency. The conclusion of this research is every antenna only has one optimum working frequency in a band (but it is not harmonic band). This information is important and can be used as references for any practitioner in field of telemetry system and tele-control although for radio communication practitioner. (author)

  14. Antenna complexes protect Photosystem I from Photoinhibition

    Hienerwadel Rainer


    Full Text Available Abstract Background Photosystems are composed of two moieties, a reaction center and a peripheral antenna system. In photosynthetic eukaryotes the latter system is composed of proteins belonging to Lhc family. An increasing set of evidences demonstrated how these polypeptides play a relevant physiological function in both light harvesting and photoprotection. Despite the sequence similarity between antenna proteins associated with the two Photosystems, present knowledge on their physiological role is mostly limited to complexes associated to Photosystem II. Results In this work we analyzed the physiological role of Photosystem I antenna system in Arabidopsis thaliana both in vivo and in vitro. Plants depleted in individual antenna polypeptides showed a reduced capacity for photoprotection and an increased production of reactive oxygen species upon high light exposure. In vitro experiments on isolated complexes confirmed that depletion of antenna proteins reduced the resistance of isolated Photosystem I particles to high light and that the antenna is effective in photoprotection only upon the interaction with the core complex. Conclusion We show that antenna proteins play a dual role in Arabidopsis thaliana Photosystem I photoprotection: first, a Photosystem I with an intact antenna system is more resistant to high light because of a reduced production of reactive oxygen species and, second, antenna chlorophyll-proteins are the first target of high light damages. When photoprotection mechanisms become insufficient, the antenna chlorophyll proteins act as fuses: LHCI chlorophylls are degraded while the reaction center photochemical activity is maintained. Differences with respect to photoprotection strategy in Photosystem II, where the reaction center is the first target of photoinhibition, are discussed.

  15. Evolutionary Optimization of a Quadrifilar Helical Antenna

    Lohn, Jason D.; Kraus, William F.; Linden, Derek S.; Clancy, Daniel (Technical Monitor)


    Automated antenna synthesis via evolutionary design has recently garnered much attention in the research literature. Evolutionary algorithms show promise because, among search algorithms, they are able to effectively search large, unknown design spaces. NASA's Mars Odyssey spacecraft is due to reach final Martian orbit insertion in January, 2002. Onboard the spacecraft is a quadrifilar helical antenna that provides telecommunications in the UHF band with landed assets, such as robotic rovers. Each helix is driven by the same signal which is phase-delayed in 90 deg increments. A small ground plane is provided at the base. It is designed to operate in the frequency band of 400-438 MHz. Based on encouraging previous results in automated antenna design using evolutionary search, we wanted to see whether such techniques could improve upon Mars Odyssey antenna design. Specifically, a co-evolutionary genetic algorithm is applied to optimize the gain and size of the quadrifilar helical antenna. The optimization was performed in-situ in the presence of a neighboring spacecraft structure. On the spacecraft, a large aluminum fuel tank is adjacent to the antenna. Since this fuel tank can dramatically affect the antenna's performance, we leave it to the evolutionary process to see if it can exploit the fuel tank's properties advantageously. Optimizing in the presence of surrounding structures would be quite difficult for human antenna designers, and thus the actual antenna was designed for free space (with a small ground plane). In fact, when flying on the spacecraft, surrounding structures that are moveable (e.g., solar panels) may be moved during the mission in order to improve the antenna's performance.

  16. 组合型抗干扰天线%Combined anti-interference antenna

    陈智达; 廖林; 彭顺全


    圆极化微带贴片天线在自适应阵抗干扰系统得到了广泛应用,天线阵系统小型化也是其中一个趋势,但由于抗干扰天线单元多,分布密集,并且同频间耦合严重,影响天线阵的整体性能。通过提出了一种组合型天线设计方案,并设计一款组合型北斗B3&S的天线,应用于8单元抗干扰阵系统上来验证该方案的有效性。该天线工作于1.268 GHz和2.492 GHz,底盘尺寸直径为180 mm,传统天线B3采用35×35,ε=16,传统天线S采用30×30,ε=6;本设计方案采用一体式天线形式,尺寸采用50×50,ε=10的介质板,一个单元里面同时实现B3频段以及S频段。布阵间距为B3半波长;与传统的微带圆极化天线相比,该设计方案优点在于,B3天线与S天线的一体式设计。不仅满足了天线多单元的布阵需要,并且通过改善各单元的间距以及辐射尺寸,有效提高天线仰角增益。%Circular polarization microstrip patch antenna is widely used in the adaptive array system for anti-interference, antenna array system miniaturization is one of the trend, but as a result of anti-interference antenna unit, distribution, and the same frequency coupling between serious, affect the overall performance of antenna array. This paper proposes a combined antenna design, which is a combination of beidou B3&S antenna applied to 8 unit array anti-interference system to verify the effectiveness of the proposed scheme. The antenna works in the 1.268 GHz and 2.492 GHz, chassis size 180 mm diameter, conventional antenna B3 is 35 × 35, epsilon=16, traditional antenna S uses 30 ×30, epsilon=6;this design adopts the form of an integral antenna, using 50×50, epsilon=10 medium plate, a unit at the same time achieves B3 frequency band and S band, spirit and spacing for B3 half wavelength; Compared with the traditional microstrip circularly polarized antenna, B3 antenna and antenna S unibody design not only

  17. Light-Harvesting Antenna System from the Phototrophic Bacterium Roseiflexus castenholzii

    Collins, Aaron M. [Washington Univ., St. Louis, MO (United States); Qian, Pu [Univ. of Sheffield (United Kingdom); Tang, Qun [Univ. of California, Riverside, CA (United States); Bocian, David F [Univ. of California, Riverside, CA (United States); Hunter, C. Neil [Univ. of Sheffield (United Kingdom); Blankenship, Robert E. [Washington Univ., St. Louis, MO (United States)


    Photosynthetic organisms have evolved diverse light-harvesting complexes to harness light of various qualities and intensities. Photosynthetic bacteria can have (bacterio)chlorophyll Qy antenna absorption bands ranging from ~650 to ~1100 nm. This broad range of wavelengths has allowed many organisms to thrive in unique light environments. Roseiflexus castenholzii is a niche-adapted, filamentous anoxygenic phototroph (FAP) that lacks chlorosomes, the dominant antenna found in most green bacteria, and here we describe the purification of a full complement of photosynthetic complexes: the light-harvesting (LH) antenna, reaction center (RC), and core complex (RC-LH). By high-performance liquid chromatography separation of bacteriochlorophyll and bacteriopheophytin pigments extracted from the core complex and the RC, the number of subunits that comprise the antenna was determined to be 15 ± 1. Resonance Raman spectroscopy of the carbonyl stretching region displayed modes indicating that 3C-acetyl groups of BChl a are all involved in molecular interactions probably similar to those found in LH1 complexes from purple photosynthetic bacteria. Finally, two-dimensional projections of negatively stained core complexes and the LH antenna revealed a closed, slightly elliptical LH ring with an average diameter of 130 ± 10 Å surrounding a single RC that lacks an H-subunit but is associated with a tetraheme c-type cytochrome.

  18. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    Teperik, Tatiana V., E-mail: [Univ. Paris-Sud, Institut d’Electronique Fondamentale, UMR 8622, Orsay F-91405 (France); Donostia International Physics Center, Aptdo. 1072, 20080 San Sebastian (Spain); Lustrac, André de [Univ. Paris-Sud, Institut d’Electronique Fondamentale, UMR 8622, Orsay F-91405 (France); Univ. Paris-Ouest, 92410 Ville d’Avray (France)


    We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF) antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012)], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%.

  19. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF) antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012)], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%

  20. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    Tatiana V. Teperik


    Full Text Available We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%.

  1. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    Teperik, Tatiana V.; de Lustrac, André


    We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF) antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012)], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%.

  2. Investigation of microwave antennas with improved performances

    Zhou, Rongguo

    This dissertation presents the investigation of antennas with improved performances at microwave frequencies. It covers the following three topics: the study of the metamaterial with near-zero index of refraction and its application in directive antenna design, the design technique of a wideband circularly polarized patch antenna for 60GHz wireless application and the investigation of a novel direction of arrival (DOA) estimation technique inspired by human auditory system. First, the metamaterial composed of two-dimensional (2-D) metallic wire arrays is investigated as an effective medium with an effective index of refraction less than unity (neff effective medium parameters (permittivity epsilon eff, permeability mueff and neff ) of a wire array are extracted from the finite-element simulated scattering parameters and verified through a 2-D electromagnetic band gap (EBG) structure case study. A simple design methodology for directive monopole antennas is introduced by embedding a monopole within a metallic wire array with neff effect of the monopole antenna is demonstrated in both simulation and experiment at X-band (8 -- 12 GHz). The measured antenna properties including return loss and radiation patterns are in good agreement with simulation results. Parametric studies of the antenna system are performed. The physical principles and interpretations of the directive monopole antenna embedded in the wire array medium are also discussed. Second, a fully packaged wideband circularly polarized patch antenna is designed for 60GHz wireless communication. The patch antenna incorporates a diagonal slot at the center and features a superstrate and an air cavity backing to achieve desired performances including wide bandwidth, high efficiency and low axial ratio. The detailed design procedure of the circularly polarized antenna, including the design of the microstrip-fed patch antenna and the comparison of the performances of the antenna with different feeding interfaces

  3. Adaptive Lighting

    Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper


    Adaptive LightingAdaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled i...

  4. A Novel Broadband MIMO/OFDM System Using Adaptive Modulation and Adaptive Diversity

    PANYahan; KhaledBenLetaief; CAOZhigang; QIUYonghong


    OFDM (Orthogonal frequency division multiplexing) has been widely regarded as an effective modulation technique for mitigating the effects of ISI in a frequency selective fading channel and for providing reliable high-data transmission over wireless links. Adaptive modulation combined with adaptive transmit and receive diversity can achieve further increases in system's capacity and bandwidth efficiency, as well as in QoS improvement in conventional OFDM systems. In this paper, we propose a novel broadband MIMO/OFDM system using adaptive modulation and adaptive transmit and receive diversity. By applying an EVD on each sub-carrier channel matrix, joint optimal transmit and receive antenna weights as well as maximal SNR on each sub-carrier are obtained. Then, by employing adaptive modulation on each sub-carrier, the maximal SNR on each sub-carrier obtained by adaptive transmit and receive diversity is further maximized through adaptive bit assignment and power assignment on each sub-carrier under the constraint of power and overall bit rate. Simulation results show that the proposed system can achieve better performance than an adaptive antenna array based OFDM system without adaptive modulation over multipath fading channels.

  5. Planetary protection for Europa radar sounder antenna

    Aaron, Kim M.; Moussessian, Alina; Newlin, Laura E.; Willis, Paul B.; Chen, Fei; Harcke, Leif J.; Chapin, Elaine; Jun, Insoo; Gim, Yonggyu; McEachen, Michael; Allen, Scotty; Kirchner, Donald; Blankenship, Donald


    The potential for habitability puts stringent requirements on planetary protection for a mission to Europa. A long-wavelength radar sounder with a large antenna is one of the proposed instruments for a future Europa mission. The size and construction of radar sounding antennas make the usual methods of meeting planetary protection requirements challenging. This paper discusses a viable planetary protection scheme for an antenna optimized for Europa radar sounding. The preferred methodology for this antenna is exposure to 100 kGy (10 Mrad) in water of gamma radiation using a Cobalt-60 source for both bulk and surface sterilization and exposure to vapor hydrogen peroxide for surface treatment for possible recontamination due to subsequent handling. For the boom-supported antenna design, selected tests were performed to confirm the suitability of these treatment methods. A portion of a coilable boom residual from an earlier mission was irradiated and its deployment repeatability confirmed with no degradation. Elasticity was measured of several fiberglass samples using a four-point bending test to confirm that there was no degradation due to radiation exposure. Vapor hydrogen peroxide treatment was applied to the silver-coated braid used as the antenna radiating element as it was the material most likely to be susceptible to oxidative attack under the treatment conditions. There was no discernable effect. These tests confirm that the radar sounding antenna for a Europa mission should be able tolerate the proposed sterilization methods.

  6. Design of silicon-based fractal antennas

    Ghaffar, Farhan A.


    This article presents Sierpinski carpet fractal antennas implemented in conventional low resistivity (Ï =10 Ω cm) as well as high resistivity (Ï =1500 Ω cm) silicon mediums. The fractal antenna is 36% smaller as compared with a typical patch antenna at 24 GHz and provides 13% bandwidth on high resistivity silicon, suitable for high data rate applications. For the first time, an on-chip fractal antenna array is demonstrated in this work which provides double the gain of a single fractal element as well as enhanced bandwidth. A custom test fixture is utilized to measure the radiation pattern and gain of these probe-fed antennas. In addition to gain and impedance characterization, measurements have also been made to study intrachip communication through these antennas. The comparison between the low resistivity and high resistivity antennas indicate that the former is not a suitable medium for array implementation and is only suitable for short range communication whereas the latter is appropriate for short and medium range wireless communication. The design is well-suited for compact, high data rate System-on-Chip (SoC) applications as well as for intrachip communication such as wireless global clock distribution in synchronous systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:180-186, 2013; View this article online at DOI 10.1002/mop.27245 Copyright © 2012 Wiley Periodicals, Inc.

  7. Compact Triple Band Slotted Microstrip Patch Antenna

    Ram Singh Kushwaha


    Full Text Available This paper presents a compact triple band slot microstrip patch antenna for 1.7/2.92 GHz WLAN applications. The radiating element of the proposed antenna consists of Swastika symbol slot operating at 1.8 GHz, 2.09 GHz, and 2.92 GHz bands. The antenna size is very compact (50 mm x 50 mm x 1.6 mm and covers 1.8 GHz to 2.92 GHz and can be used for AMPS, GSM and WLAN applications. The antenna is fed from a single 50 Ω coaxial cable. Using IE3D software package of Zeland, according to the set size, the antenna is simulated. The composite effect of integrating these techniques and by introducing the novel slotted patch offers a low profile, wide bandwidth, high gain and compact antenna element. The computer simulation results show that the antenna can realize wide band characters with each band having good impedance bandwidth (VSWR ≤ 2 for all the three resonant frequencies.

  8. Compact Directional Microwave Antenna for Localized Heating

    Fink, Patrick W.; Lin, Gregory Y.; Chu, Andrew W.; Dobbins, Justin A.; Arndt, G. Dickey; Ngo, Phong


    A directional, catheter-sized cylindrical antenna has been developed for localized delivery of microwave radiation for heating (and thus killing) diseased tissue without excessively heating nearby healthy tissue. By "localized" is meant that the antenna radiates much more in a selected azimuthal direction than in the opposite radial direction, so that it heats tissue much more on one side than it does on the opposite side. This antenna can be inserted using either a catheter or a syringe. A 2.4-mm prototype was tested, although smaller antennas are possible. Prior compact, cylindrical antennas designed for therapeutic localized hyperthermia do not exhibit such directionality; that is, they radiate in approximately axisymmetric patterns. Prior directional antennas designed for the same purpose have been, variously, (1) too large to fit within catheters or (2) too large, after deployment from catheters, to fit within the confines of most human organs. In contrast, the present antenna offers a high degree of directionality and is compact enough to be useable as a catheter in some applications.

  9. Logo Antenna for 5.8 GHz Wireless Communications

    Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne

    A logo antenna for the 5.8 GHz ISM band is presented. The idea behind the logo antenna is to use the company or university logo as part of the antenna. When disguised as a logo, it may be more acceptable to place the antenna at optimal locations to obtain good coverage. In the present work the un...

  10. Multiport antenna systems for space-time communications

    Tsakalaki, Elpiniki; Alrabadi, Osama; Pelosi, Mauro; Pedersen, Gert Frølund

    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...

  11. 47 CFR 80.290 - Auxiliary receiving antenna.


    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Auxiliary receiving antenna. 80.290 Section 80... antenna. An auxiliary receiving antenna must be provided when necessary to avoid unauthorized interruption or reduced efficiency of the required watch because the normal receiving antenna is not...

  12. 47 CFR 24.55 - Antenna structures; air navigation safety.


    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Antenna structures; air navigation safety. 24... SERVICES PERSONAL COMMUNICATIONS SERVICES Technical Standards § 24.55 Antenna structures; air navigation safety. Licensees that own their antenna structures must not allow these antenna structures to become...

  13. 47 CFR 17.4 - Antenna structure registration.


    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Antenna structure registration. 17.4 Section 17... ANTENNA STRUCTURES General Information § 17.4 Antenna structure registration. (a) Effective July 1, 1996, the owner of any proposed or existing antenna structure that requires notice of proposed...

  14. 47 CFR 27.56 - Antenna structures; air navigation safety.


    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Antenna structures; air navigation safety. 27... SERVICES MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Technical Standards § 27.56 Antenna structures; air navigation safety. A licensee that owns its antenna structure(s) must not allow such antenna structure(s)...

  15. CPW to CPS transition for feeding UWB antennas

    Butrym, Alexander; Pivnenko, Sergey


    The paper considers a transition (balun) from Coplanar Waveguide (CPW) to Coplanar Stripline (CPS) which is non-resonant and suitable for feeding UWB antennas such as Tapered Slot Antennas (Vivaldi antennas, in particular), bow-tie antennas, and other. Some numerical and experimental results are...

  16. CPW to CPS transition for feeding UWB antennas

    Butrym, Alexander; Pivnenko, Sergey


    The paper considers a transition (balun) from Coplanar Waveguide (CPW) to Coplanar Stripline (CPS) which is non-resonant and suitable for feeding UWB antennas such as Tapered Slot Antennas (Vivaldi antennas in particular), bow-tie antennas, and other. Some numerical and experimental results are...

  17. CPW to CPS transition for feeding UWB antennas

    Butrym, Alexander; Pivnenko, Sergey

    The paper considers a transition (balun) from Coplanar Waveguide (CPW) to Coplanar Stripline (CPS) which is non-resonant and suitable for feeding UWB antennas such as Tapered Slot Antennas (Vivaldi antennas in particular), bow-tie antennas, and other. Some numerical and experimental results are...

  18. An Adaptive Channel Model for VBLAST in Vehicular Networks

    Ghassan M. T. Abdalla


    Full Text Available The wireless transmission environment in vehicular ad hoc systems varies from line of sight with few surroundings to rich Rayleigh fading. An efficient communication system must adapt itself to these diverse conditions. Multiple antenna systems are known to provide superior performance compared to single antenna systems in terms of capacity and reliability. The correlation between the antennas has a great effect on the performance of MIMO systems. In this paper we introduce a novel adaptive channel model for MIMO-VBLAST systems in vehicular ad hoc networks. Using the proposed model, the correlation between the antennas was investigated. Although the line of sight is ideal for single antenna systems, it severely degrades the performance of VBLAST systems since it increases the correlation between the antennas. A channel update algorithm using single tap Kalman filters for VBLAST in flat fading channels has also been derived and evaluated. At 12 dB Es/N0, the new algorithm showed 50% reduction in the mean square error (MSE between the actual channel and the corresponding updated estimate compared to the MSE without update. The computational requirement of the proposed algorithm for a p×q VBLAST is 6p×q real multiplications and 4p×q real additions.

  19. Smart antenna technology for structural health monitoring applications

    Özdemir, Tayfun; Goykhman, Yuriy; Oberdier, Larry; Lynch, Jerome


    A smart antenna has been developed for structural health monitoring. The antenna is based on Monarch's GEN 2 selfstructuring antenna (SSA) technology and provides polarization and beam-diversity for improving signal-to-noise ratio (SNR). The antenna works with University of Michigan's Narada platform, where a microcontroller monitors the RSSI and selects the best beam to maintain reliable RF link. Antenna has two wide beams for each polarization and the beams are selected by applying appropriate DC voltages to the RF switches on the antenna aperture. Paper presents the GEN C antenna, which is a smaller version of the GEN 2B with comparable performance features.

  20. Compact antennas for wireless communications and terminals theory and design

    Laheurte, Jean-Marc


    Compact Antennas for Wireless Communications and Terminals deals with compact microwave antennas and, more specifically, with the planar version of these antennas. Planar antennas are the most appropriate type of antenna in modern communication systems and more generally in all applications requiring miniaturization, integration and conformation such as in mobile phone handsets.The book is suitable for students, engineers and scientists eager to understand the principles of planar and small antennas, their design and fabrication issues, and modern aspects such as UWB antennas, recon

  1. Modeling of the EAST ICRF antenna with ICANT Code

    Qin, Chengming; Zhao, Yanping; Colas, L.; Heuraux, S.


    A Resonant Double Loop (RDL) antenna for ion-cyclotron range of frequencies (ICRF) on Experimental Advanced Superconducting Tokamak (EAST) is under construction. The new antenna is analyzed using the antenna coupling code ICANT which self-consistently determines the surface currents on all antenna parts. In this work, the modeling of the new ICRF antenna using this code is to assess the near-fields in front of the antenna and analysis its coupling capabilities. Moreover, the antenna reactive radiated power computed by ICANT and shows a good agreement with deduced from Transmission Line (TL) theory.

  2. A Review of the Four Dimension Antenna Arrays

    YANG Shi-wen; NIE Zai-ping


    The four dimensional (4D) antenna arrays introduce a fourth dimension, time, into conventional antenna arrays to offer greater flexibility in the design of high performance antenna arrays. This paper presents the tutorial on the study of 4D antenna arrays and the review of the recent research findings on 4D antenna arrays. Issues considered include the theory of 4D antenna arrays, different time modulation schemes, numerical simulation results, and some experimental results on their applications to low sidelobe designs. Throughout the discussion, some challenging issues on the study of 4D antenna arrays are highlighted.

  3. Location Refinement and Power Coverage Analysis Based on Distributed Antenna

    赵晓楠; 侯春萍; 汪清; 陈华; 浦亮洲


    To establish wireless channel suitable for the cabin environment, the power coverage was investigated with distributed antenna system and centralized antenna system based on the actual measurement of channel im-pulse response. The results indicated that the distributed antenna system has more uniform power coverage than the centralized antenna system. The average relative errors of receiving power of both antennas were calculated. The optimal position of the centralized antenna was obtained by Gaussian function refinement, making the system achieve a better transmission power with the same coverage effect, and providing a reference for antenna location in the future real communication in the cabin.

  4. Design of Monopole Antenna Based on Fractal Geometry

    Zhao Yuanqing; Qiu Jinghui; Wang Wei


    This paper presents a circular disc monopole antenna based on fractal geometry. The antenna is designed to be applied in UWB systems. So it is essential to ensure that the bandwidth of the antenna ranges from 3.1 GHz to 10.6 GHz, that is, IEEE 802.15.3a. However, the proposed antenna has achieved working in the required bandwidth. Compared to the antennas illustrated in most similar literatures, the proposed antenna has a much smaller size, which makes the antenna possible to be integrated wi...

  5. Multifrequency broadband polarized horn antenna

    Green, K. A.


    A corrugated conical horn antenna is simultaneously fed a multiplicity of signals, two for each of five frequencies, with each of a pair of signals fed in each of two orthogonal planes for excitation of a desired spherical hybrid mode. The lowest frequency is fed into the horn through orthogonal pairs of colinear slots, each pair being fed by coaxial tee power dividers. Other signals are fed through a circular waveguide connected to the vertex. The highest frequency signals are fed through orthogonal ports near the far end of the circular waveguide. The intermediate frequency signals are fed through orthogonal ports spaced along the waveguide. Filtering is incorporated for each to maintain isolation and low insertion loss.

  6. Smart antennas for nuclear instruments

    The advances in the field of computer and communications are leading to the development of smart embedded nuclear instruments. These instruments have highly sophisticated signal-processing algorithms based on FPGA and ASICS, provisions of present day connectivity and user interfaces. The developments in the connectivity, standards and bus technologies have made possible to access these instruments on LAN and WAN with suitable reliability and security. To get rid of wires i.e. in order to access these instruments, without wires at any place, wireless technology has evolved and become integral part of day-to-day activities. The environment monitoring can be done remotely, if smart antennas are incorporated on these instruments

  7. Wireless communication capability of a reconfigurable plasma antenna

    A 30 cm long plasma column is excited by a surface wave, which acts as a plasma antenna. Using plasma properties (pattern formation/striations in plasmas) single plasma antenna can be transformed into array, helical, and spiral plasma antenna. Experiments are carried out to study the power patterns, directivity, and half power beam width of such different plasma antennas. Moreover, field properties of plasma and copper antenna are studied. Further, wireless communication and jamming capability of plasma antenna are tested. Findings of this study suggest that directivity and communication range can be increased by converting single plasma antenna in to array/helical/spiral plasma antenna. Field frequencies of plasma antenna determine the communication and jamming of radio frequency waves. Therefore, this study invokes applications of pattern formation or striations of plasmas in plasma antenna technology.

  8. Vertically Polarized Omnidirectional Printed Slot Loop Antenna

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper;


    A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...... pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due to the polarization....

  9. Lens Antenna For Mobile/Satellite Communication

    Bodnar, D. G.; Rainer, B. K.


    Flat, compact antenna made of stripline elements aimed at fixed elevation angle but steered electronically in azimuth. Design simplified by maintaining fixed elevation and relying on width of beam to cover desired elevation range. Need for phase shifter at each radiating element eliminated by arranging elements in circles and feeding through stripline disks called "R-KR lenses". Used in Mobile/Satellite Service, antenna mounted on top of vehicle on Earth and used to keep transmitted and received antenna beams aimed approximately toward communication satellite.

  10. Innovation in wearable and flexible antennas

    Khaleel, Haider


    This book deals with the design, numerical simulation, state of the art fabrication processes and methods, qualitative and quantitative tests, and measurement techniques of wearable and flexible antennas of different topologies, such as: Planar Inverted F, Printed Monopoles, Micropoles and Microstrips. Novel trends, materials, and fabrication and measurement techniques used in this vital field of antenna systems are also discussed.To the best of the editor's knowledge, at the time of publication, there are no published books targeting the vital topic of flexible antennas specifically and/or se

  11. Ultra-wideband conformal helmet antenna

    Lebaric, J.; Ah-Tuan Tan


    The article of record may be found at This paper presents the development of an ultra-wideband (300 to 3000 MHz), vertically polarized, nearly omni-directional (in azimuth) communications antenna integrated into the camouflage cover of a standard military-issue Kevlar helmet. The Helmet Camouflage Cover Antenna (referred to as the “helmet antenna”) is one of three antennas (with the combined frequency coverage from 2 to 2000 MHz) based on the an...

  12. Implanted Antennas in Medical Wireless Communications

    Rahmat-Samii, Yahya; Balanis, Constantine


    Implanted Antennas in Medical Wireless Communications summarizes the results of recent research activities on the subject of implanted antennas for medical wireless communication systems. It is anticipated that in the near future sophisticated medical devices will be implanted inside the human body for medical telemetry and telemedicine. To establish effective and efficient wireless links with these devices, it is pivotal to give special attention to antenna designs that are low profile, small, safe, and cost effective. In this book, authors Yahya Rahmat-Samii and Jaehoon Kim demonstrate how a

  13. Experimental demonstration of superdirective dielectric antenna

    Krasnok, Alexander E.; Filonov, Dmitry S.; Belov, Pavel A. [National Research University of Information Technologies, Mechanics and Optics (ITMO), St. Petersburg 197101 (Russian Federation); Simovski, Constantin R. [National Research University of Information Technologies, Mechanics and Optics (ITMO), St. Petersburg 197101 (Russian Federation); Aalto University, School of Electric and Electronic Engineering, Aalto FI76000 (Finland); Kivshar, Yuri S. [National Research University of Information Technologies, Mechanics and Optics (ITMO), St. Petersburg 197101 (Russian Federation); Nonlinear Physics Center, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)


    We propose and demonstrate experimentally a simple approach for achieving superdirectivity of emitted radiation for electrically small antennas based on a spherical dielectric resonator with a notch excited by a dipole source. Superdirectivity is achieved without using complex antenna arrays and for a wide range of frequencies. We also demonstrate the steering effect for a subwavelength displacement of the source. Finally, unlike previously known superdirective antennas, our design has significantly smaller losses, at the operation frequency radiation efficiency attains 80%, and matching holds in the 3%-wide frequency band without any special matching technique.

  14. Wideband Circularly Polarized Dielectric Rod Antenna

    Min Guo; Ji-Jun Yan; Shun-Shi Zhong; Zhu Sun


    A new dielectric rod antenna (DRA) is introduced to produce circular polarization (CP) over a wide frequency band without a complex feed network. Along with the simulated results, measured results of the antenna prototype are presented, showing a 3 dB axial ratio (AR) CP bandwidth of 17.7%. The radiation characteristics of the fabricated antenna are also demonstrated showing the measured gain of better than 6.2 dBi. Moreover, the measured impedance bandwidth (VSWR ≤2) reaches 20.1%, from 8.75...

  15. Build a circularly polarized waveguide slot antenna

    Kisliuk, M.; Axelrod, A.


    The development and design of a circularly polarized waveguide slot antenna are described. Consideration is given to the resonance frequency, radiation efficiencies, excitement, and resonant conductance of the transverse and longitudinal slots. The transverse and longitudinal slots in a rectangular guide are analyzed. The voltage distribution across the slot is calculated from the solution of a standard transmission line equation; and using the Poynting theorem the fields scattered by the slot in an arbitrary frequency range are determined. The proposed antenna is examined using an equivalent circuit; a diagram of the circuit is given. The radiation, slot, and antenna efficiencies are measured.

  16. Channels, propagation and antennas for mobile communications

    Vaughan, Rodney; Bach Andersen, J


    This exceptional text introduces the reader to the theory and basis of antennas and propagation in the rapidly developing field of mobile communications. Topics covered include basic multipath mechanisms and propagation, and propagation modelling as well as short term channel behavior from two path and many path models and scenarios. Also, the basics of antenna design and operation are discussed including array antennas. This book promises to be a valuable reference work for many years to come, and will be an important addition to the bookshelves of telecommunications engineers and researcher

  17. Resonant double loop antenna development at ORNL

    As part of the development of ion cyclotron resonant heating (ICRH) systems for fusion research, Oak Ridge National Laboratory (ORNL) has built resonant double loop (RDL) antennas for the Tokamak Fusion Test Reactor (TFTR) (Princeton Plasma Physics Laboratory, Princeton, NJ, US) and Tore Supra (Centre d'Etudes Nucleaire, Cadarache, France). Each antenna has been designed to deliver 4 MW of power. The electrical circuit and the mechanical philosophy employed are the same for both antennas, but different operating environments lead to substantial differences in the designs of specific components. A description and a comparison of the technologies developed in the two designs are presented. 5 refs., 4 figs., 1 tab

  18. Planar Tri-Band Antenna Design

    M. Pokorny


    Full Text Available The paper briefly uncovers techniques used for a design of compact planar antennas in order to achieve the wideband and the multi-band capability. The main topic is aimed to the multi-objective optimization using genetic algorithms. A quarter-wavelength planar inverted-F antenna (PIFA using a slot and shorted parasitic patches is chosen to cover GSM900, GSM1800 and ISM2400 bands. A global multi-objective optimization uses a binary genetic algorithm with a composite objective function to tune this antenna. The impedance match and the direction of maximum gain are desired parameters to improve.

  19. Slot Antenna for Wireless Temperature Measurement Systems

    Acar, Öncel; Jakobsen, Kaj Bjarne


    This paper presents a novel clover-slot antenna for a surface-acoustic-wave sensor based wireless temperature measurement system. The slot is described by a parametric locus curve that has the shape of a clover. The antenna is operated at high temperatures, in rough environments, and has a 43......% fractional bandwidth at the 2.4 GHz ISM-band. The slot antenna has been optimized for excitation by a passive chip soldered onto it. Measurement results are compared with simulation results and show good agreements....

  20. A directional antenna for borehole radar

    The borehole radar system developed during phase II of the International Stripa Project has been successfully applied to mapping fracture zones up to 100 meters from the borehole in granite. The techniques previously used to determine the orientation of fracture zones (single hole reflection, crosshole reflection, crosshole tomography) have been supplemented with a directional antenna, which makes it possible to determine the orientation from measurements in a single borehole. The antenna works by synthesizing four signals to produce directional information. Tests performed in Stripa show that the resolution of the antenna is about 50

  1. Smooth Tracking Trajectory Generation of Large Antenna

    Upnere S.


    Full Text Available The current paper presents an engineering approach for studies of the control algorithm designed for a mechanically robust large antenna. Feed-forward control methods with the 3rd-order polynomial tracking algorithm are supplemented to the original feed-back PID control system. Dynamical model of the existing servo system of 32m radio telescope has been developed to widen a case analysis of observation sessions and efficiency of the control algorithms due to limited access to an antenna. Algorithms along with the results from the system implemented on a real antenna as well as model results are presented.

  2. Wideband Reconfigurable Rolled Planar Monopole Antenna

    Ruvio, Giuseppe; Ammann, Max


    A novel technique to reconfigure the frequency range of a planar monopole antenna is presented. By adjusting the degree of spiral tightness, a shift of the well-matched operating frequency range is achieved. The proposed antenna is capable of covering the frequencies in the range from 2.9 to 15 GHz, depending on the degree of spiral tightness. The antenna yields a high-efficiency across the full operating bandwidth. Radiation patterns show good omni-directional features in all primary cuts an...

  3. Antenna development for high field plasma imaging

    Kong, X.; Domier, C. W.; Luhmann, N. C. Jr. [Department of Applied Science, University of California at Davis, Davis, California 95616 (United States)


    Electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) are two microwave nonperturbing plasma visualization techniques that employ millimeter-wave imaging arrays with lens-coupled planar antennas, yielding time-resolved images of temperature (via ECEI) and electron density (via MIR) fluctuations within high temperature magnetic fusion plasmas. A series of new planar antennas have been developed that extend this technology to frequencies as high as 220 GHz for use on high field plasma devices with toroidal fields in excess of 3 T. Antenna designs are presented together with theoretical calculations, simulations, and experimental measurements.

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

    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.

  5. Low-Gain Circularly Polarized Antenna with Torus-Shaped Pattern

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


    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

  6. State-of-the-art and trends of Ground-Penetrating Radar antenna arrays

    Vescovo, Roberto; Pajewski, Lara; Tosti, Fabio


    directions, including the synthesis of arrays with a high directivity achieved by using simple elements, arrays with the capability of a steerable beam as in smart antennas, arrays composed of adaptive antennas with electronic control of characteristics to adapt to different soils and materials, and application-specific arrays. Acknowledgement This abstract is a contribution to COST (European COoperation in Science and Technology) Action TU1208 "Civil engineering applications of Ground Penetrating Radar" ( The Authors thank COST for funding the Action TU1208.

  7. Technique for Radiometer and Antenna Array Calibration with Two Antenna Noise Diodes

    Srinivasan, Karthik; Limaye, Ashutosh; Laymon, Charles; Meyer, Paul


    This paper presents a new technique to calibrate a microwave radiometer and phased array antenna system. This calibration technique uses a radiated noise source in addition to an injected noise sources for calibration. The plane of reference for this calibration technique is the face of the antenna and therefore can effectively calibration the gain fluctuations in the active phased array antennas. This paper gives the mathematical formulation for the technique and discusses the improvements brought by the method over the existing calibration techniques.

  8. UHF RFID Antenna: Printed Dipole Antenna with a CPS Matching Circuit and Inductively Coupled Feed

    Nenad Popović


    This paper presents simulated (WIPL‐D pro) and measured results of a UHF RFID antenna realized with a dipole matched to a CPS (Coplanar Stripline) and inductively coupled with a small rectangular loop. Such a design enables achieving and controlling high values of the inductive reactance that is necessary for obtaining good match of the antenna to an Application Specific Integrated Circuit (ASIC) chip. The antenna is characterized by a simple and robust design, which results in low‐cost re...

  9. Range-Angle-Dependent Beamforming by Frequency Diverse Array Antenna

    Wen-Qin Wang; Huaizong Shao; Jingye Cai


    This paper proposes a range-angle-dependent beamforming for frequency diverse array (FDA) antenna systems. Unlike conventional phased-array antenna, the FDA antenna employs a small amount of frequency increment compared to the carrier frequency across the array elements. The use of frequency increment generates an antenna pattern that is a function of range, time and angle. The range-angle-dependent beamforming allows the FDA antenna to transmit energy over a desired range or angle. This prov...

  10. A Linearly and Circularly Polarized Active Integrated Antenna

    Khoshniat, Ali


    This thesis work presents a new harmonic suppression technique for microstrip patch antennas. Harmonic suppression in active integrated antennas is known as an effective method to improve the efficiency of amplifiers in transmitter side. In the proposed design, the antenna works as the radiating element and, at the same time, as the tuning load for the amplifier circuit that is directly matched to the antenna. The proposed active antenna architecture is easy to fabricate and is symmetric, so ...

  11. Circularly Polarized Solar Antenna for Airborne Communication Nodes

    O’Conchubhair, Oisiin; Narbudowicz, Adam; McEvoy, Patrick; Ammann, Max


    A circularly polarized solar cell antenna consisting of four sequentially rotated printed inverted-F antennas is proposed. Four multicrystalline silicon solar cells act as the ground plane and the antenna is suitable for low power airborne communication nodes and wireless sensor networks. The antenna design was developed to allow 100% insolation of the cells when directly facing a light source. The low-profile antenna minimises shadowing of the solar cell for oblique angle insolation.

  12. Antenna Evaluation for Ultra-Wideband Microwave Imaging

    Elise C. Fear; Trevor Williams; Campbell, Mark A.; Jeremie Bourqui


    Numerous antenna designs have been proposed for microwave breast imaging utilizing an ultra-wideband frequency range. The antennas are typically compact, operate in an immersion medium, and have a band covering at least 2–10 GHz. We have developed 3 antennas for our UWB microwave breast imaging system. In this contribution, we compare the performance of the antennas in order to gain insight into the relationship between antenna performance metrics and image quality.

  13. Modern antenna measurements and diagnostics including phaseless techniques

    Rahmat-Samii, Yahya; Yaccarino, R. G.


    Microwave antenna imaging techniques are a practical and popular method for antenna diagnostic analysis. Phase retrieval methods, however, are just beginning to emerge as an alternative mircowave antenna measurements technique when phase cannot be directly measured. This article focuses on recent advances in microwave antenna imaging, diagnostic techniques, and phase retrieval methods for bi-polar planar near-field antenna measurements. An overview of the bi-polar planar near-field technique ...

  14. Planar MIMO Antenna with Slits for WBAN Applications

    Do-Gu Kang; Jinpil Tak; Jaehoon Choi


    A planar MIMO antenna with slits for WBAN applications is proposed. The antenna consists of two PIFAs, ground pads, and two slits. By adding ground pads, the antenna size is reduced with improved impedance matching. Through two slits in a ground plane, the isolation characteristic is improved and the resonant frequency can be controlled. To analyze the antenna performance on a human body, the proposed antenna on a human equivalent flat phantom is investigated through simulations. Regardless o...

  15. A Novel Wideband Semi-planar Miniaturized Antenna

    Ruvio, Giuseppe; Ammann, Max


    A semi-planar miniaturized antenna which operates over the FCC allocated UWB spectrum is presented. The small antenna comprises a folded conducting element connected to a printed section. Several solutions are introduced which create different current paths increasing the effective dimensions of the antenna. The antenna is examined for the stand-alone case and for the antenna mounted in various locations on a larger handset-type groundplane. The impedance and radiation characteristics ...

  16. An Introduction of Aperture Coupled Microstrip Slot Antenna

    Zarreen Aijaz; S.C Shrivastava


    A microstrip slot antenna is very small and lightweight still it has the problem of back radiation due to which power loss occurs and the SAR increases. To reduce the back lobe a technique introduces i.e. aperture coupled microstrip slot antenna which reduces the back lobe as well as increases the bandwidth of the antenna. Aperture coupled microstrip slot antenna couples the patch antenna with microstripline through an aperture.

  17. Directional Pattern Analysis of a Linear Phased Antenna

    Jan Haring


    Full Text Available An antenna array is a system compound from simply radiators (dipoles, microstrip antennas, that together form desired radiation pattern. Phased array antennas consist of multiple stationary antenna elements, that are fed coherently and use variable phase or time-delay control at each element to scan a beam to given angles in space. Variable amplitude control is sometimes also provided for antenna pattern shaping.

  18. Dual-Frequency Operation of Bow-Tie Microstrip Antenna

    钟顺时; 张需溥


    Characteristics of a single-feed dual-frequency bow-tie microstrip antenna are studied. By using the variation method, simple formulas for resonant frequencies of the bow-tie microstrip antenna are derived. It is shown that the dual-frequency ratio can be controlled easily by choosing the parameters of the antenna. This design gives compact antenna size and simple antenna structure. Experimental results are presented, verifying the validity of the design.

  19. Planar Millimeter-Wave Antennas: A Comparative Study

    K. Pitra


    Full Text Available The paper describes the design and the experimental verification of three types of wideband antennas. Attention is turned to the bow-tie antenna, the Vivaldi antenna and the spiral antenna designed for the operation at millimeter waves. Bandwidth, input impedance, gain, and directivity pattern are the investigated parameters. Antennas are compared considering computer simulations in CST Microwave Studio and measured data.

  20. Performance Characterization of Radial Stub Microstrip Bow-Tie Antenna

    B.T.P.Madhav; S.S. Mohan Reddy; Neha Sharma; J. Ravindranath Chowdary; Bala Rama Pavithra; K.N.V.S. Kishore; G Sriram; B. Sachin Kumar


    In this paper a novel radial stub feeding microstrip bow-tie antenna is designed to operate between C and X band and its performance characterization is presented. This antenna is having simple structure and topology over other stub loaded antennas. In addition the proposed antenna adjusts to the desired frequency easily. Antenna output parameters like radiation pattern, axial ratio, directive gain andquality factor are simulated and presented in this current work.

  1. Performance Characterization of Radial Stub Microstrip Bow-Tie Antenna



    Full Text Available In this paper a novel radial stub feeding microstrip bow-tie antenna is designed to operate between C and X band and its performance characterization is presented. This antenna is having simple structure and topology over other stub loaded antennas. In addition the proposed antenna adjusts to the desired frequency easily. Antenna output parameters like radiation pattern, axial ratio, directive gain andquality factor are simulated and presented in this current work.

  2. Time-domain antenna studies for videopulse subsurface radars

    Boryssenko, Anatoliy O.


    The results of time-domain theoretical and experimental studies of ultra-wide band antennas with impulse excitation in radiating and receiving modes are presented. The antennas under consideration, like a monopole antenna, a dipole antenna and a horn-like antenna, are used widely for high-resolution videopulse subsurface (ground-penetrating) radars and should be operated near the border between two medias with different electrical properties.

  3. Automated Antenna Design with Evolutionary Algorithms

    Linden, Derek; Hornby, Greg; Lohn, Jason; Globus, Al; Krishunkumor, K.


    Current methods of designing and optimizing antennas by hand are time and labor intensive, and limit complexity. Evolutionary design techniques can overcome these limitations by searching the design space and automatically finding effective solutions. In recent years, evolutionary algorithms have shown great promise in finding practical solutions in large, poorly understood design spaces. In particular, spacecraft antenna design has proven tractable to evolutionary design techniques. Researchers have been investigating evolutionary antenna design and optimization since the early 1990s, and the field has grown in recent years as computer speed has increased and electromagnetic simulators have improved. Two requirements-compliant antennas, one for ST5 and another for TDRS-C, have been automatically designed by evolutionary algorithms. The ST5 antenna is slated to fly this year, and a TDRS-C phased array element has been fabricated and tested. Such automated evolutionary design is enabled by medium-to-high quality simulators and fast modern computers to evaluate computer-generated designs. Evolutionary algorithms automate cut-and-try engineering, substituting automated search though millions of potential designs for intelligent search by engineers through a much smaller number of designs. For evolutionary design, the engineer chooses the evolutionary technique, parameters and the basic form of the antenna, e.g., single wire for ST5 and crossed-element Yagi for TDRS-C. Evolutionary algorithms then search for optimal configurations in the space defined by the engineer. NASA's Space Technology 5 (ST5) mission will launch three small spacecraft to test innovative concepts and technologies. Advanced evolutionary algorithms were used to automatically design antennas for ST5. The combination of wide beamwidth for a circularly-polarized wave and wide impedance bandwidth made for a challenging antenna design problem. From past experience in designing wire antennas, we chose to

  4. An Overview of Antenna R&D Efforts in Support of NASA's Space Exploration Vision

    Manning, Robert M.


    This presentation reviews the research and development work being conducted at Glenn Research Center in the area of antennas for space exploration. In particular, after reviewing the related goals of the agency, antenna technology development at GRC is discussed. The antennas to be presented are large aperture inflatable antennas, phased array antennas, a 256 element Ka-band antenna, a ferroelectric reflectarray antenna, multibeam antennas, and several small antennas.

  5. Cylindrical Dielectric Resonator Antennas with Harmonic Control as an Active Antenna Radiator

    L. Lucci


    Full Text Available A cylindrical dielectric resonator antenna is proposed as a radiator for an active integrated antenna. Harmonic tuning, which is the key step in designing active antenna radiators, is achieved via a combination of shape factor control over the resonator and insertion of reactive elements in the feed system. Numerical simulations are carried out in a finite elements framework and a layout for the complete antenna is proposed, aimed at compactness for subsequent utilization of the radiator as an element in an active array for satellite communications.

  6. Fluorescence Enhancement Factors on Optical Antennas: Enlarging the Experimental Values without Changing the Antenna Design

    Jérôme Wenger


    Full Text Available Plasmonic antennas offer promising opportunities to control the emission of quantum objects. As a consequence, the fluorescence enhancement factor is widely used as a figure of merit for a practical antenna realization. However, the fluorescence enhancement factor is not an intrinsic property of the antenna. It critically depends on several parameters, some of which are often disregarded. In this contribution, I explore the influence of the setup collection efficiency, emitter's quantum yield, and excitation intensity. Improperly setting these parameters may significantly alter the enhancement values, leading to potential misinterpretations. The discussion is illustrated by an antenna example of a nanoaperture surrounded by plasmonic corrugations.

  7. Modelling of mixed-phasing antenna-plasma interactions on JET A2 antennas

    The use of mixed(monopole-dipole)-phasing of a set of ion cyclotron range of frequency antennas is potentially useful to optimize tokamak performance. However, recent mixed-phasing experiments on JET, described here, showed undesirable antenna-plasma interactions under certain circumstances. A possible physical mechanism to explain the experimental results is discussed, namely, rf-driven dc parallel currents flowing between adjacent antennas with different phasings can lead to arcing on the antenna with the largest sheath voltage. Means of controlling the interaction are discussed. (author)

  8. Stochastic Control of Event-Driven Feedback in Multi-Antenna Interference Channels

    Huang, Kaibin; Lau, Vincent K. N.; Kim, Dongku


    Spatial interference avoidance is a simple and effective way of mitigating interference in multi-antenna wireless networks. The deployment of this technique requires channel-state information (CSI) feedback from each receiver to all interferers, resulting in substantial network overhead. To address this issue, this paper proposes the method of distributive control that intelligently allocates CSI bits over multiple feedback links and adapts feedback to channel dynamics. For symmetric channel ...

  9. Novel microstrip antenna array for anti-jam satellite navigation system

    Martynyuk, Sergiy Ye.; Vasylenko, Dmytro O.; Dubrovka, Fedor F.; Laush, Anatolii G.


    We present results of theoretical and experimental investigations of a novel dual band right hand circularly polarized microstrip antenna array with adaptive space-time processing capability for terminal of GPS/GLONASS/GALILEO satellite navigation systems. The array structure is composed from 10 microstrip radiators excited independently via separate coaxial input ports. Two central radiating elements for two frequency bands (L1 and L2) have got circular shapes with slits and are stacked to p...

  10. Study on Smart Antenna Systems and Implementation in Mobile Ad Hoc Networks

    Supriya Kulkarni P


    Full Text Available Wireless carriers have begun to explore new ways to maximize the spectral efficiency of their networks. Research efforts investigating methods of improving wireless systems performance are currently being conducted worldwide by the deployment of smart antennas (SAs along with impressive advances in the field of digital signal processing for achieving high efficiency networks that maximize capacity and improve quality and coverage. Selected control algorithms, with predefined criteria, provide adaptive arrays the unique ability to increase spectral efficiency.

  11. Wireless Energy and Information Transfer Tradeoff for Limited Feedback Multi-Antenna Systems with Energy Beamforming

    Chen, Xiaoming; Yuen, Chau; Zhang, Zhaoyang


    In this paper, we consider a multi-antenna system where the receiver should harvest energy from the transmitter by wireless energy transfer to support its wireless information transmission. In order to maximize the harvesting energy, we propose to perform adaptive energy beamforming according to the instantaneous channel state information (CSI). To help the transmitter to obtain the CSI for energy beamforming, we further propose a win-win CSI quantization feedback strategy, so as to improve t...

  12. Wideband P-Shaped Dielectric Resonator Antenna



    Full Text Available A novel P-shaped dielectric resonator antenna (DRA is presented and investigated for wideband wireless application. By using P-shaped resonator, a wideband impedance bandwidth of 80% from 3.5 to 8.2 GHz is achieved. The antenna covers all of wireless systems like C-band, 5.2, 5.5 and 5.8 GHz-WLAN and WiMax. The proposed antenna has a low profile and the thickness of the resonator is only 5.12 mm, which is 0.06-0.14 free space wavelength. A parametric study is presented. The proposed DRA is built and the characteristics of the antenna are measured. Very good agreement between numerical and measured results is obtained.

  13. General properties of dielectric optical antennas.

    Schuller, Jon A; Brongersma, Mark L


    Using Mie theory we derive a number of general results concerning the resonances of spherical and cylindrical dielectric antennas. Specifically, we prove that the peak scattering cross-section of radiation-limited antennas depends only on the resonance frequency and thus is independent of refractive index and size, a result which is valid even when the resonator is atomic-scale. Furthermore, we derive scaling limits for the bandwidth of dielectric antennas and describe a cylindrical mode which is unique in its ability to support extremely large bandwidths even when the particle size is deeply subwavelength. Finally, we show that higher Q antennas may couple more efficiently to an external load, but the optimal absorption cross-section depends only on the resonance frequency. PMID:20052120

  14. Whistler wave ducting caused by antenna actions

    Whistler waves launched from an antenna damp away for small incident power. With increasing power, undamped nondiverging waves (the ducted waves) are observed, together with a field-aligned density trough and electron heating. However, the density trough is found not only in the wave propagation regime (ω/ω/sub c/1). This implies that the density depression is mainly created by the effect of the antenna near-zone field rather than by the wave radiation pressure. The intense localized field near the antenna gives rise to electron heating which leads to the density trough. The ducting of antenna-launched whistler waves has been explained as a filamentation instability in terms of nonlinear wave-plasma interactions

  15. Metamaterial Multiband Antenna for Wireless Application

    Nader AZIZI


    Full Text Available In this work a Multi-band antenna along with the innovative metamaterial structure is proposed which consists of a circular geometry incorporated with c shaped structure. This work is mainly focused on increasing the potential parameters of planar antennas and analyzing the multi band operation of proposed antenna. The impedance bandwidth of proposed antenna are covered and utilized frequency range of (2.6~3.1 GHz, (3.5~4.4 GHz and (4.7~6.2 GHz. For verifying that the proposed metamaterial structure possesses Negative values of Permeability and Permittivity within the operating frequency ranges, Nicolson-Ross-Weir method (NRW has been employed. For simulation purpose HFSS Software has been used.

  16. Implantable microwave antennas for thermal therapy

    Stauffer, Paul R.


    The purpose of this article is to review the physical construction and power deposition characteristics of interstitial microwave antennas that may be used for highly localized heating of tissue at depth in the human body. Several different antenna designs are described and matched with potential clinical applications that range from moderate temperature Hyperthermia therapy to tissue- necrosing Thermal Ablation therapy. Typical clinical procedures are outlined for thermal treatment of target sites such as brain, prostate, heart, and gynecologic region tissues. Associated methods of implanting the antennas and coupling microwave energy into the surrounding tissue are also described, including the use of single or multi-chamber stiff, flexible or inflatable balloon type catheters, with or without circulating air or water cooling. With numerous references to the primary literature, this material should provide a framework for analyzing potential new applications for interstitial microwave antennas, as derived from the physical capabilities and limitations of the available hardware and techniques.

  17. Advanced Antenna for Digital Beamforming SAR Project

    National Aeronautics and Space Administration — Develop a wideband (500 MHz) L-band phased-array antenna for airborne Synthetic Aperture Radar (SAR) applications based on a novel approach that will make possible...

  18. Phase shifter for antenna beam steering

    Jindal, Ravi; Razban, Tchanguiz


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

  19. Optimization of Far-Field Antenna Range

    O. Cerny


    Full Text Available Measurements of test antennas are performed on antenna ranges. The operated microwave far-field outdoor range was built-up in 1970’s and therefore it was not appropriate for the today measurements. Thus, it was decided to perform the complete reconstruction and testing. Some results of new ample measurement campaign are just given. The optimization of antenna range using merely measurement is very inefficient, and therefore that is done by numerical simulations. Consequently the paper surveys briefly electromagnetic wave propagation over irregular terrain. The physical optics approximation of vector problem was chosen. That allows the comparison of selected numerical simulations and measurements for the reconstructed far-field range. A possibility of antenna range optimizing by using numerical simulation considering various constraints is verified.

  20. Low Cost Phased Array Antenna System Project

    National Aeronautics and Space Administration — JEM Engineering proved the technical feasibility of the FlexScan array?a very low-cost, highly-efficient, wideband phased array antenna?in Phase I, and stands ready...

  1. Textile Antenna for 50 ohm Applications

    Robi Dahal


    Full Text Available The new generation of textile materials have the capability to conduct electricity and at the same time be wearable. There are much more applications involved if an antenna is made from parts that are totally wearable. This new property of conductivity in textile materials is used to implement the wireless functions to clothing. In general, the antennas are made of highly conductive metal with is a solid structure, which results in stable output. The challenge with textile antenna is output stability which is given by pure textile material of the radiating element, dielectric material and also ground, which can be can be folded and twisted. The paper presents the design and fabricated output results of the textile antenna which is used for the 50 ohm system (as GPS or WLAN at 2,45 GHz.

  2. Fast cooling techniques for gravitational wave antennas

    Furtado, S R


    The resonant-mass technique for the detection of gravitational waves may involve, in the near future, the cooling of very large masses (about 100 tons) from room temperature (300 K) to extreme cryogenic temperatures (20 mK). To cool these detectors to cryogenic temperatures an exchange gas (helium) is used, and the heat is removed from the antenna to the cold reservoir by thermal conduction and natural convection. With the current technique, cooling times of about 1 month can be obtained for cylindrical bar antennas of 2.5 tons. Should this same technique be used to cool a 100 ton spherical antenna the cooling time would be about 10 months, making the operation of these antennas impracticable. In this paper, we study the above-mentioned cooling technique and others, such as thermal switching and forced convection from room temperature to liquid nitrogen temperature (77 K) using an aluminium truncated icosahedron of 19 kg weight and 25 cm diameter.

  3. Development of ceramic-free antenna feeder

    We have proposed a ceramics-free antenna feeder line employing a ridged waveguide as a local support for IC antenna of next-generation tokamaks. One fourth mock-up model of the all metal waveguide designed for the ITER ICRF system is fabricated and electrical characteristics of the model including the coaxial line - waveguide converter are measured. Power reflection coefficient of the model including the coax-waveguide converter to the input coaxial line is estimated to be less than 15% below the cut-off frequency of 107 MHz and less than 3% above the cut-off frequency. It is found that this ceramics-free antenna support employing a ridged waveguide is quite available for IC antenna of next-generation tokamaks. (author)

  4. Microfabricated G-Band Antenna Arrays Project

    National Aeronautics and Space Administration — This proposal addresses the need for an antenna technology platform that meets the requirements of high-performance materials, exacting dimensional tolerances, and...

  5. Slot Coupled Patch Array Antenna Technology Project

    National Aeronautics and Space Administration — The proposed project is an antenna array whose beam is controlled digitally. The Phase 1 effort will assess the method needed to achieve the gain, bandwidth, and...

  6. PBG based terahertz antenna for aerospace applications

    Choudhury, Balamati; Jha, Rakesh Mohan


    This book focuses on high-gain antennas in the terahertz spectrum and their optimization. The terahertz spectrum is an unallocated EM spectrum, which is being explored for a number of applications, especially to meet increasing demands of high data rates for wireless space communications. Space communication systems using the terahertz spectrum can resolve the problems of limited bandwidth of present wireless communications without radio-frequency interference. This book describes design of such high-gain antennas and their performance enhancement using photonic band gap (PBG) substrates. Further, optimization of antenna models using evolutionary algorithm based computational engine has been included. The optimized high-performance compact antenna may be used for various wireless applications, such as inter-orbital communications and on-vehicle satellite communications.

  7. NRAO RF Anechoic Chamber & Antenna Range

    Federal Laboratory Consortium — A shielded anechoic chamber measuring 15 by 15 by 37 feet is located in the Jansky Laboratory at Green Bank. This chamber has been outfitted as a far-field antenna...

  8. Microfabricated Millimeter-Wave Antenna Arrays Project

    National Aeronautics and Space Administration — This proposal addresses the need for an antenna technology platform that meets the requirements of high-performance materials, exacting dimensional tolerances, and...

  9. Compact, Frequency Reconfigurable, Printed Monopole Antenna

    Ricardo Gonçalves


    Full Text Available This paper proposes a possible implementation of a compact printed monopole antenna, useful to operate in UMTS and WLAN bands. In order to accomplish that, a miniaturization technique based on the application of chip inductors is used in conjunction with frequency reconfiguration capability. The chip inductors change the impedance response of the monopole, allowing to reduce the resonant frequency. In order to be able to operate the antenna in these two different frequencies, an antenna reconfiguration technique based on PIN diodes is applied. This procedure allows the change of the active form of the antenna leading to a shift in the resonant frequency. The prototype measurements show good agreement with the simulation results.

  10. MEMS-Enabled Smart Reconfigurable Antennas Project

    National Aeronautics and Space Administration — A prototype wearable smart reconfigurable antenna for the Suit will be built to be used during NASA's EVA operations on lunar surface. The design is based on the...

  11. Adaptive skills

    Staša Stropnik; Jana Kodrič


    Adaptive skills are defined as a collection of conceptual, social and practical skills that are learned by people in order to function in their everyday lives. They include an individual's ability to adapt to and manage her or his surroundings to effectively function and meet social or community expectations. Good adaptive skills promote individual's independence in different environments, whereas poorly developed adaptive skills are connected to individual's dependency and with g...

  12. A comparison of atmospheric effects on differential phase for a two-element antenna array and nearby site test interferometer

    Morabito, David D.; D'Addario, Larry; Finley, Susan


    Phased arrays of reflector antennas can be used to obtain effective area and gain that are much larger than is practical with a single antenna. This technique is routinely used by NASA for receiving weak signals from deep space. Phase alignment of the signals can be disrupted by turbulence in the troposphere, which causes fluctuations in the differences of signal delays among the antennas. At the Deep Space Network stations, site test interferometers (STIs) are being used for long-term monitoring of these delay fluctuations using signals from geostationary satellites. In this paper, we compare the STI measurements with the phase variations seen by a nearby two-element array of 34 m diameter antennas tracking 8.4 GHz and 32 GHz signals from the Cassini spacecraft in orbit around Saturn. It is shown that the statistics of the STI delay fluctuations, after appropriate scaling for differences in antenna separation and elevation angle and conversion to phase at the spacecraft frequencies, provide reliable estimates of the phase fluctuations seen by the large antennas on the deep space signal. Techniques for adaptive compensation of the phase fluctuations are available when receiving a sufficiently strong signal, but compensation is often impractical or impossible when using the array for transmitting. These results help to validate the use of long-term STI data for assessing the feasibility of large transmitting arrays at various sites.

  13. Deployable Wide-Aperture Array Antennas

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


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

  14. The investigation of radiation characteristics of Fresnel antenna for Q-band

    Magro, V. I.; Morozov, V M


    The general approach to analysis of zonal Fresnel antenna is considered. The frequency characteristics of Fresnel antenna are analyzed. The radiation characteristics of the Fresnel antenna are considered.

  15. Multiple Antenna Systems with Inherently Decoupled Radiators

    Pelosi, Mauro; Knudsen, Mikael B.; Pedersen, Gert Frølund


    In multiple antenna systems mutual coupling needs to be minimized. We propose an alternative novel decoupling technique, investigating several multiple antenna configurations for small handsets through measurements and numerical simulations. The influence of different novel designs on performance...... inherently decoupled when integrated on the same handset, while also other parameters such as frequency duplex distance and interaction with the users body influence the mutual coupling....

  16. Nonlinear effects in microwave antenna feeds

    Semenikhina, Diana V.


    The theoretical basis for the analysis of experimentally observed nonlinear effects and associated electromagnetic compatibility problems in microwaves antenna feeds has been absent so far. This caused the necessity of carrying out the present work. The paper is aimed on the research of interior nonlinear electromagnetic problems. Here, the analysis of nonlinear effects arising in microstrip antenna feed line on a concentrated nonlinear element such as diode is carried out. Evaluations of non...

  17. Deep Space Network Antenna Logic Controller

    Ahlstrom, Harlow; Morgan, Scott; Hames, Peter; Strain, Martha; Owen, Christopher; Shimizu, Kenneth; Wilson, Karen; Shaller, David; Doktomomtaz, Said; Leung, Patrick


    The Antenna Logic Controller (ALC) software controls and monitors the motion control equipment of the 4,000-metric-ton structure of the Deep Space Network 70-meter antenna. This program coordinates the control of 42 hydraulic pumps, while monitoring several interlocks for personnel and equipment safety. Remote operation of the ALC runs via the Antenna Monitor & Control (AMC) computer, which orchestrates the tracking functions of the entire antenna. This software provides a graphical user interface for local control, monitoring, and identification of faults as well as, at a high level, providing for the digital control of the axis brakes so that the servo of the AMC may control the motion of the antenna. Specific functions of the ALC also include routines for startup in cold weather, controlled shutdown for both normal and fault situations, and pump switching on failure. The increased monitoring, the ability to trend key performance characteristics, the improved fault detection and recovery, the centralization of all control at a single panel, and the simplification of the user interface have all reduced the required workforce to run 70-meter antennas. The ALC also increases the antenna availability by reducing the time required to start up the antenna, to diagnose faults, and by providing additional insight into the performance of key parameters that aid in preventive maintenance to avoid key element failure. The ALC User Display (AUD) is a graphical user interface with hierarchical display structure, which provides high-level status information to the operation of the ALC, as well as detailed information for virtually all aspects of the ALC via drill-down displays. The operational status of an item, be it a function or assembly, is shown in the higher-level display. By pressing the item on the display screen, a new screen opens to show more detail of the function/assembly. Navigation tools and the map button allow immediate access to all screens.

  18. Antenna Splitting Functions for Massive Particles

    Larkoski, Andrew J.; Peskin, Michael E.; /SLAC


    An antenna shower is a parton shower in which the basic move is a color-coherent 2 {yields} 3 parton splitting process. In this paper, we give compact forms for the spin-dependent antenna splitting functions involving massive partons of spin 0 and spin 1/2. We hope that this formalism we have presented will be useful in describing the QCD dynamics of the top quark and other heavy particles at LHC.

  19. Highly sensitive beam steering with plasmonic antenna

    Guanghao Rui; Qiwen Zhan


    In this work, we design and study a highly sensitive beam steering device that integrates a spiral plasmonic antenna with a subwavelength metallic waveguide. The short effective wavelength of the surface plasmon polaritons (SPPs) mode supported by the metallic waveguide is exploited to dramatically miniaturize the device and improve the sensitivity of the beam steering. Through introducing a tiny displacement of feed point with respect to the geometrical center of the spiral plasmonic antenna...

  20. Broadband high efficiency active integrated antenna

    Qin, Yi


    Active integrated antenna (MA) is a very popular topic of research during recent decades. This is mostly due to its advantages, such as compact size, multiple functions and low cost, etc. The MA system can be regarded as an active microwave circuit which the output or input port is free space instead of a conventional 50-ohm interface. The major drawbacks of the conventional MA include narrow bandwidth, low efficiency, etc. An experimental investigation on broadband slot-coupled antenna is ca...

  1. Circularly Polarized Broadband RFID Microstrip Tag Antenna

    B. Rajini; G. V. Subrahmanyam


    In recent years, the application of radio frequency identification (RFID) operating in the ultra-high frequency (UHF) band (860-960MHz) are expanding exponentially, due to the advantages such as long reading distance, high data transfer rate, and small tag size. So the design of a CP tag antenna with broadband characteristic is presently one of the most challenging topics. This project presents a square patch passive RFID tag antenna designed for UHF band. To a...

  2. Investigation of a Short Conical Helix Antenna

    Nakano, Hisamatsu; Mikawa, Takao; Yamauchi, Junji


    The input impedance, radiation pattern, axial ratio, and power gain of a conical helix antenna with a short arm are calculated as a function of frequency, using theoretically determined current distributions. It is shown that the antenna radiates a circularly polarized wave over a frequency range ratio of about 1:1.2, having a power gain of about 7.7 dB. The experimental results are also presented.

  3. Optimization of RFID antenna web materials

    Perttu, Inkeri


    Radio frequency identification can be used to identify items which have antenna attached. The use of radio frequency identification continues to grow which leads to the development of the industry. Antennas can be manufactures with several methods. Etching is the most common method and the substrate used is polyethylene terephthalate (PET). This Master’s Thesis is about more sustainable manufacturing method and materials used in the process. The investigated process manufactures first a s...

  4. Optical nano-antennas and metamaterials

    Sailing He; Yanxia Cui; Yuqian Ye; Pu Zhang; Yi Jin


    We review some recent approaches to transmission enhancement and light harvesting based on optical nano-antennas and metamaterials. Nano-cavity antennas are used to enhance the extraordinary transmission of TM-polarized light through vertical nano-slits in a metal film. The enhanced transmission of TE-polarized waves through an array of subwavelength-slits in a thin metal film at low frequencies (including microwave) is also investigated. Light harvesting with a metamaterial cloaking shell is...

  5. Broadband Approximations for Doubly Curved Reflector Antenna

    V. Schejbal; J. Pidanic


    The broadband approximations for shaped-beam doubly curved reflector antennas with primary feed (rectangular horn) producing uniform amplitude and phase aperture distribution are derived and analyzed. They are very valuable for electromagnetic compatibility analyses both from electromagnetic interference and susceptibility point of view, because specialized more accurate methods such as physical optics are only used by antenna designers. To allow quick EMC analyses, typical values, beamwidth ...


    Gao Feng; Liu Qizhong; Shan Runhong; Zhang Hou


    This letter investigates an efficient design procedure integrating the Genetic Algorithm (GA) with the Finite Difference Time Domain (FDTD) for the fast optimal design of Smart Antenna Arrays (SAA). The FDTD is used to analyze SAA with mutual coupling. Then,on the basis of the Maximal Signal to Noise Ratio (MSNR) criteria, the GA is applied to the optimization of weighting elements and structure of SAA. Finally, the effectiveness of the analysis is evaluated by experimental antenna arrays.

  7. 3D Printing Electrically Small Spherical Antennas

    Kim, Oleksiy S.


    3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations.......3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations....

  8. Far-infrared imaging antenna arrays

    Neikirk, Dean P.; Rutledge, David B.; Muha, Michael S.; Park, Hyeon; Yu, Chang-Xuan


    A far-infrared imaging antenna array has been demonstrated for the first time. The array is a line of evaporated silver bow-tie antennas on a fused-quartz substrate with bismuth-microbolometer detectors. The measured optical transfer function shows that the system is diffraction limited. This imaging array should find direct application in fusion plasma diagnostics. If the microbolometers can be replaced by more sensitive diode detectors, the array should also find application in radiometry a...

  9. Broadband circularly polarized antennas for UHF SATCOM

    Tekin, İbrahim; Tekin, Ibrahim; Manzhura, Oksana; Niver, Edip


    Novel circularly polarized (CP) antenna configurations derived from Moxon type antenna (bent dipole element over a ground plane) for broadband VHF SATCOM applications. A sequence of topologies starting from a single vertical element to two vertical elements of the Moxon arms, then widened strip arm elements were studied. Further, arms were widened to bow tie structures with bents at 900.for achieving broadband operation. Bow tie elements were further split and optimized at a certain angle to...

  10. Adjusting Surfaces Of Large Antenna Reflectors

    Padula, Sharon L.; Adelman, Howard M.; Bailey, Marion C.; Hoftka, Raphael T.


    New approach more effective than traditional rms-surface-distortion approach. Optimization procedure for control of shape of reflector of large space antenna (LSA). Main feature is shape-controlling mathematical mechanism driven by need to satisfy explicit EM design requirements. Uses standard finite-element structural analysis, aperture-integration EM analysis, and constrained optimization techniques to predict set of actuator inputs that improves performance of antenna while minimizing applied control effort. Procedure applicable to wide variety of LSA concepts.

  11. Design and Development of VSAT Antenna Feed .

    S. Christopher


    Full Text Available The paper deals with the design and development of a dual polarised corrugated conical horn employed as a feed for parabolic reflector antennas used in very small aperture terminal applications. The VSAT antenna feed is designed, fabricated and tested to operate over a band from 3.7 GHz to 6.5GHz with good pattern symmetry, low side lobes and low cross-polarisation.

  12. Electronically steerable millimeter-wave antennas

    Varadan, Vijay K.; Varadan, Vasundara V.; Jose, K. A.; Kelly, James F.


    In this paper, electronically steerable microstrip and leaky wave antennas using tunable ferroelectric material are proposed. These antennas are lightweight, low volume, low profile, and conformal. They have low fabrication costs and are easily mass produced. They are thin and do not perturb the aerodynamics of a host automobile or aircraft. Linear, circular, and dual polarization are achieved with simple changes in feed position. Beam steering is accomplished by varying the relative phase between radiating elements. In planar array, both horizontal and vertical beam can be combined to provide full scanning capabilities. Tunable ceramic phase shifters are used in these antennas. In microstrip antennas, they are deposited as thin films on the feed lines whereas in the leaky wave antennas they have been used as a traveling waveguide with a ground plane on one side and metallic periodic grating on the opposite side. The dielectric properties of the ferroelectric material are changed by a bias voltage applied to the waveguide which in turn controls the leaky wave direction of the antenna. A simple experiment is presented which shows a good agreement with the theoretical prediction.

  13. ICRF antenna performance on Tore Supra

    Goulding, R. H.; Carter, M. D.; Harris, J. H.; Hoffman, D. J.; Hogan, J. T.; Ryan, P. M.; Beaumont, B.; Bremond, S.; Hutter, T.


    Resonant double loop (RDL) ion cyclotron range of frequencies (ICRF) Antennas have operated on Tore Supra at power levels up to ˜3.5 MW per 2-element launcher. The RDL configuration is of particular interest because it has operated at high power densities (15 MW/m2 on Tore Supra) and is the topology chosen for the ITER ICRF launchers. Two Faraday shield designs are in use which produce different loading for nearly identical antenna radial positions, and different heating patterns on antenna surfaces due to rf/edge plasma interaction. Loading and maximum antenna voltage for a given power level have been found to vary between the different antennas in a frequency dependent manner. This behavior has been analyzed using a lossy transmission model. In addition, antenna surface heating patterns have been found to be highly phase dependent and reproducible over time. Strong localized power fluxes are often observed to determine the launcher power limit rather than internal voltages and currents.

  14. ICRF antenna performance on Tore Supra

    Resonant double loop (RDL) ion cyclotron range of frequencies (ICRF) Antennas have operated on Tore Supra at power levels up to ∼3.5MW per 2-element launcher. The RDL configuration is of particular interest because it has operated at high power densities (15MW/m2 on Tore Supra) and is the topology chosen for the ITER ICRF launchers. Two Faraday shield designs are in use which produce different loading for nearly identical antenna radial positions, and different heating patterns on antenna surfaces due to rf/edge plasma interaction. Loading and maximum antenna voltage for a given power level have been found to vary between the different antennas in a frequency dependent manner. This behavior has been analyzed using a lossy transmission model. In addition, antenna surface heating patterns have been found to be highly phase dependent and reproducible over time. Strong localized power fluxes are often observed to determine the launcher power limit rather than internal voltages and currents. copyright 1997 American Institute of Physics

  15. Adaptive Lighting

    Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper


    Adaptive Lighting Adaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities...... offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled in ways that meaningfully adapt according to people’s situations and design intentions. This book discusses...... distributed differently into an architectural body. We also examine what might occur when light is dynamic and able to change colour, intensity and direction, and when it is adaptive and can be brought into interaction with its surroundings. In short, what happens to an architectural space when artificial...

  16. Advanced ICRF antenna design for R-TOKAMAK

    The advanced ICRF antennas designed for the R-TOKAMAK (a proposal in the Institute of Plasma Physics, Nagoya University) are described. They are a standard loop antenna and a panel heater antenna for fast wave heating, and a waveguide antenna for ion Bernstein wave heating. The standard loop antenna is made of Al-alloy and has a simple structure to install because of radioactivation by D-T neutrons. For a high power heating, a new type antenna called 'Panel heater antenna' is proposed, and it has a wide radiation area and is able to select a parallel wave number. The field pattern of the panel heater antenna is measured. The feasibility of the waveguide antenna is discussed for the ion Bernstein wave heating. The radiation from the aperture of the double ridge waveguide is experimentally estimated with a load simulating the plasma. (author)

  17. Improvement of Power Efficiency using Smart Antenna System in MANETs

    Abhishek Kumar


    Full Text Available Performance of ad-hoc networks is low under omnidirectional antenna systems compared to smart antenna system. Directional antennas cover large area {&} save some amount of transmitted power because it focuses in desired direction accordance with mobility of nodes while Omni-directional antennas cover small area {&} needs large transmitted power as compared to Smart Antenna System (SAS. In this paper, we will overcome the problem of unnecessary transmitted power wastage with omnidirectional antenna system in ad-hoc wireless networks by using Smart Antenna Systems (SAS. We will calculate {&} analyze transmitted power variations with different number of mobile nodes in mobile ad-hoc networks [MANETs] with smart antenna system (SAS {&} Omni-directional antenna system in different conditions. Firstly, we will calculate {&} analyze transmitted power during flooding of packets means in case of route creation, and secondly, when communication will established between transmitter {&} receiver

  18. Analysis of equivalent antenna based on FDTD method

    Yun-xing YANG; Hui-chang ZHAO; Cui DI


    An equivalent microstrip antenna used in radio proximity fuse is presented. The design of this antenna is based on multilayer multi-permittivity dielectric substrate which is analyzed by finite difference time domain (FDTD) method. Equivalent iterative formula is modified in the condition of cylindrical coordinate system. The mixed substrate which contains two kinds of media (one of them is air)takes the place of original single substrate. The results of equivalent antenna simulation show that the resonant frequency of equivalent antenna is similar to that of the original antenna. The validity of analysis can be validated by means of antenna resonant frequency formula. Two antennas have same radiation pattern and similar gain. This method can be used to reduce the weight of antenna, which is significant to the design of missile-borne antenna.

  19. Analysis of equivalent antenna based on FDTD method

    Yun-xing Yang


    Full Text Available An equivalent microstrip antenna used in radio proximity fuse is presented. The design of this antenna is based on multilayer multi-permittivity dielectric substrate which is analyzed by finite difference time domain (FDTD method. Equivalent iterative formula is modified in the condition of cylindrical coordinate system. The mixed substrate which contains two kinds of media (one of them is airtakes the place of original single substrate. The results of equivalent antenna simulation show that the resonant frequency of equivalent antenna is similar to that of the original antenna. The validity of analysis can be validated by means of antenna resonant frequency formula. Two antennas have same radiation pattern and similar gain. This method can be used to reduce the weight of antenna, which is significant to the design of missile-borne antenna.

  20. Design of Monopole Antenna Based on Fractal Geometry

    Zhao Yuanqing


    Full Text Available This paper presents a circular disc monopole antenna based on fractal geometry. The antenna is designed to be applied in UWB systems. So it is essential to ensure that the bandwidth of the antenna ranges from 3.1 GHz to 10.6 GHz, that is, IEEE 802.15.3a. However, the proposed antenna has achieved working in the required bandwidth. Compared to the antennas illustrated in most similar literatures, the proposed antenna has a much smaller size, which makes the antenna possible to be integrated with portable devices. Firstly, the antenna was designed through CST Microwave Studio. Then, the antenna was fabricated according to the simulated results. At last, the comparison between the simulated results and measured results was carried out which demonstrated good consistency.