New Publications are available for Antenna arrays
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New Publications are available now online for this publication.
Please follow the links to view the publication.Spatial domain mitigation of out of band strong interferers in HF wide band acquisition using analog beamforming principles
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0382
We envision that dynamic multiband transmissions taking advantage of the receiver diversity (even for collocated antennas with different polarization or radiation pattern) will create a new paradigm for these links guaranteeing high quality and reliability. However, there are many challenges to face regarding the use of broadband reception where several out of band (with respect to multiband transmission) strong interferers, but still within the acquisition band, may limit dramatically the expected performance. In this paper we address this problem introducing a specific capability of the communication system that is able to mitigate these interferences using analog beamforming principles. Indeed, Higher Order Crossing (HOCs) joint statistics of the Single Input - Multiple Output (SIMO) system are shown to effectively determine the angle on arrival of the wavefront even operating over highly distorted signals. (5 pages)WR-3 band butler matrix design using SU-8 photo-resist technology
http://dl-live.theiet.org/content/conferences/10.1049/ic.2012.0061
A design of WR-3 band 2×2 Butler Matrix feeding a 2-element slotted waveguide antenna array is presented in this paper. The whole design is based on an SU-8 multi-layer structure, which is expected to be fabricated by metal-coated SU-8 thick resist technology [1]. Each layer of the SU-8 wafer has a thickness of 0.432mm, which matches the narrow-wall height of a WR-3 (220-325GHz) waveguide. To examine the performance of the proposed Matrix, prior to adding antennas, a simulation on the 90 degree resonator based hybrid coupler was carried out using the CST Microwave Studio [2]. The simulation results agree well with the theoretical predictions, validating the proposed design.Experimental investigations of MIMO in the HF band
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0394
Previously, the majority of developments in the area of multiple input multiple output (MIMO) technology have been confined to short-range wireless applications operating in the VHF, UHF and SHF bands, with very little research conducted in the lower frequency bands. Recently, several experimental campaigns have been performed over a 255 km radio link between Durham and Leicester in the UK in order to investigate the feasibility of applying MIMO techniques to communications within the HF band. Results have indicated that traditional spaced HF antenna arrays can be replaced by compact, active, heterogeneous arrays with the consequence that de-correlation between the various antenna elements is achieved at a single location. This paper summarises the details of compact antenna arrays and presents significant results obtained on deploying these antenna arrays. (4 pages)Integrating MIMO technology into the WiMEdia UWB framework for WPANs
http://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0606
In order to address the ever increasing demand for capacity in Wireless Personal Area Networks (WPAN); the framework associated with the WiMedia Ultra Wide Band (UWB) standard has been implemented in many WPAN systems. To increase capacity, Multiple Input Multiple Output (MIMO) technology is a well-established antennae technology that can not only increase system capacity, but can also extend the link coverage area for wireless communication systems. In this paper, a review of existing research in the implementation of MIMO into the UWB domain is presented, and a model is proposed for its implementation. Initial simulations in terms of performance analysis of bit error rates and throughput are then presented, and show the significant improvements the proposed model can provide. (5 pages)Adaptive decision feedback detection with constellation constraints for multi-antenna systems
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0150
A low-complexity decision feedback (DF) detection algorithm with constellation constraints (DFCC) is proposed for multiple-antenna systems. An enhanced detection and interference cancellation is achieved by introducing the constellation constraints (CC). For time-varying channels, the proposed receiver updates the filter weights using recursive least squares (RLS) algorithm. This highly efficient detector is also incorporated in a multiple branch (MB) structure to achieve a higher detection diversity order. Simulations show that the proposed DFCC technique has a complexity as low as the conventional adaptive DF detector while it achieves a significant performance improvement. (5 pages)A dynamic resource allocation model along with adaptive power control in a multi-rate direct sequence CDMA with MIMO
http://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0074
A throughput maximization algorithm for a CDMA system comprising of variable bit rate (VBR) groups has been proposed. The algorithm is aimed at efficiently utilizing the radio resources for maximal throughput while meeting the minimum data transmission rate and Quality of Service (QoS) requirements of each user group. The power of each group is also dynamically controlled so as to minimize the cell interference thereby maximizing the system capacity. The model also predicts the reduction in effective cell radius because of cell breathing under Gaussian noise and a Rayleigh faded channel. The simulation of multiple input multiple output (MIMO) antenna in such a system reports an improvement in the Bit Error Rate (BER) performance of the system by up to 80%. The allocation scheme efficiently utilizes as much as 99.9% of the available bandwidth in the system.Design and development of 4 element linear micro strip patch antenna array with null steering by phase control
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0441
The paper presents design and development of a linear microstrip patch antenna array and also, a method to change the radiation pattern of the array by steering null in the desired direction. This is achieved by changing the phase of each of the array element which produces a null in the radiation pattern without significantly affecting the main beam lobe. Different methods can be used for array synthesis. In this paper the Schelkunoff polynomial method is used for the synthesis of array. For an N element array, (N-I) nulls can be formed. The array is designed around a frequency of 930 MHz using four microstrip patch antenna elements of rectangular shape arranged in linear configuration. The theoretical design of the antenna array is presented initially and then the results of the array simulation and the hardware implementation are presented.Designing a fading MIMO channel for capacity enhancement
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0442
A channel model under has been designed for fading environments using which channel capacity of a MIMO system can be enhanced. The channel which proposed here between transmitter and receiver is Rayleigh flat fading and both the transmitter and receiver are unknown about the fading coefficient. As an efficient antenna array is being used here at the receiver which will increase the SNR and will give the high value of channel capacity. A linear antenna array gives high value of SNR and beam width which can be considered at the receiver. Under Rayleigh fading channel capacity varies linearly with number of antenna elements.Tacking mutual coupling in antenna arrays for wireless communications
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.1076
A new model for tacking mutual coupling in wireless communications is introduced. A new concept of receiving mutual impedance is introduced and explained theoretically. Receiving mutual impedances for typical antenna arrays are obtained. Application of the new method is demonstrated in several arrays for direction finding, adaptive nulling, and MIMO communications. (5 pages)Joint uplink user scheduling and power allocation in cognitive MIMO system
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0736
In this paper, we investigate the problem of the multi-user uplink scheduling in cognitive radio cellular network. The objective is to maximize the system throughput, while protecting the QoS of primary user (PU) from being affected by cognitive user (CU). Here, PU's QoS is represented by its rate outage probability and it also reflects on the interference temperature (IT). It is equivalent to say that CUs can increase transmit power to enhance the system performance as long as PU's outage probability does not exceed the predefined threshold. We assume that the cognitive base station (CBS) is equipped with M antennas and all CUs has one antenna that means CBS can at most allow M CUs to access simultaneously. We focus on user scheduling schemes for this uplink of multiple user single-input multiple-output (MU-SIMO) system in cognitive radio network (CRN). Meanwhile, we formulate the water-filling power allocation problem at that condition. The first scheduling algorithm is proposed to maximize the system throughput through utilizing the multi-user diversity and spatial multiplexing gain. Due to the first algorithm which does not take the fairness among CUs into account, so we propose the second scheduling algorithm with considering fairness among CUs. It provides a satisfactory tradeoff between maximizing the system performance and achieving fairness among CUs. Finally, these proposed algorithms are validated through extensive simulations.Power consumption modelling of radio-over-fiber distributed antenna system based wireless sensor network
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.1470
This paper innovatively proposes a solution to choose an energy efficiency radio-over-fiber (RoF) distributed antenna system (DAS) based wireless sensor network (WSN) by modelling the total power consumption of the network. It is shown that for a given power consumption value, the tradeoff among the number of remote access units (RAUs), the number of MIMO antennas and the number of hops must be taken into account. And our quantified results provide basis for selecting a suitable RoF DAS based WSN with an appropriate number of hops before future actual deployment.Capacity degradation of representative antenna selection algorithms and an antenna selection scheme
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0972
In this paper, we concentrated on investigating the performance of some representative antenna selection algorithms, and attributed the channel capacity degradation of these algorithms to two aspects: The idealized assumption or under utilization of the channel matrix for computational convenient purpose and, the local searching strategy that existing in almost all the suboptimal antenna selection algorithms. Based on these analysis, we introduced a joint antenna selection scheme, which can slightly improve the performances of the existing suboptimal algorithms by searching the local optimal of the selection result of the suboptimal antenna selection algorithm.Research on BS antenna configuration in TD-LTE system
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0801
The performance of employing three typical BS antenna configurations of the TD-LTE system is evaluated in this work. Simulation result of three typical antenna configurations shows that the 0.7 λ column spacing 4 columns 8 antenna elements dual polarized smart antenna is a cost-effective way for the TD-LTE system. The UL cell average SE (SE) of 0.7 λ 8 antenna compared to 2 antenna achieves about 35.45% minimum gain. The UL cell edge SE of 0.7 λ 8 antenna compared to 2 antenna achieves about 37.93% minimum gain. The DL cell average SE of 0.7 λ 8 antenna compared to 2 antenna obtains about 7.87% minimum gain. The DL cell edge SE of 0.7 λ 8 antenna compared to 2 antenna obtains about 16.71%. minimum gain Relative to 2 antenna, the maximum coverage distance using 0.7 λ 8 antenna can be increased by 38.24%.DOA estimation algorithm of MIMO system
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0649
In this paper, we propose a method of direction of arrival (DOA) estimation which is called complex spatial specturm method (CSM). Advantages and disadvantages of the multiple signal classification (MUSIC) algorithm and the Reciprocal Weighted of Signal subspace principal eigenvalue Projection (RWSP) algorithm are discussed in the paper. By combing the advantages of two algorithms, the information of signal subspace and noise subspace are used in CSM. The feasibility of CSM which uses spatial spectrum estimation is proved theoretically. Simulation results indicate that the CSM is a high resolution and robustness algorithm for resolving multiple incoherent and coherent signals that are incident on an array of antenna.Robust joint beamforming for MIMO broadcast system with limited feedback
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0624
In Multiple-In Multiple-Out (MIMO) Broadcast systems with limited feedback, when receivers are equipped with multiple antennas, the so-called quantization error of channel direction matrix was unavoidably introduced. This quantization error will result in the reduction of system capacity since it was referenced in the beamforming design. In this paper, we proposed a robust beamforming method based on MMSE, which considers the statistical characteristics of the quantization error for channel direction matrix. Simulation results show that the proposed method effectively enhanced system capacity, reduced bit error rate (BER), as well as mitigated the Plateau Effect.Performance analysis and comparison of adaptive beam forming algorithms for smart antenna systems
http://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0211
Smart Antenna Systems (SAS) are deployed in wireless communication system to improve the spectrum efficiency, eliminate the multi-access interference, co-channel interference (CCI) and the multi-path fading [1]. This intelligence enables the antenna systems to improve the range, quality and coverage of the system and leads to maximize the system capacity. This is achieved by beam forming algorithms and auto tracking of the desired signals. This uses the transmitted signals from a fixed set of antenna elements in an array which are weighted and combined to form a steering beam that tracks a mobile unit (MU) as it moves. This allows the SAS to dynamically focus radio frequency resources on a particular MU with minimal noise, interference and allied degrading effects. A systematic comparison and performance analysis of algorithms like Recursive Least Squares (RLS), Least Mean Squares (LMS) and Constant Modulus Algorithm (CMA) has been done in this paper. The analysis parameters used for comparison of above algorithms are response towards beam forming, interference rejection, convergence and bit error rate (BER). (5 pages)Analogue network coding for multi-pair, bidirectional relay channels
http://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0247
We consider a scenario where multiple pairs of users exchange information within pair, with the help of a dedicated multi-antenna relay. The proposed protocol integrates the idea of analogue network coding in mixing two data streams originating from the same user pair, together with the spatial multiplexing of the data streams originating from different user pairs. We propose several beamforming schemes and evaluate the performance using information theoretical metrics such as ergodic capacity and outage probability. Simulation results justify that the ergodic capacity and the outage probability of the proposed beamforming schemes outperforms comparable schemes. (5 pages)The system model and analysis of all-digital temporal and spatial anti-jamming for GPS receivers
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0665
GPS signal is very weak and easily influenced by interference or jamming. An antenna array with adaptive algorithm combing with temporal anti-jamming processing can be used to mitigate interference and improve GPS signal acquisition and tracking performance. This paper addresses an all digital temporal and spatial anti-jamming implementation scheme based on adaptive antenna array. Temporal adaptive Altering techniques can effectively suppress narrowband interference, which is less ability to code with broadband interference. However, the presence of an antenna array allows the receiver to operate in spatial domain in addition to time or frequency domain, which can improve the performance of GPS receiver with broadband interference. Simulation results show the scheme can greatly enhance the robustness of GPS receiver in a large number of interference signals.Spatial multiplexing algorithms of cognitive base-stations
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0656
The existing cognitive network can not provide the spatial sectors for a cell, since the base-station (BS) has one omnidirectional antenna. Thus it is impossible for a base-band channel to be shared by several mobile stations(MSs) with one omni-directional antenna. To solve the problem, this paper proposes the spatial multiplexing algorithms for transmitter and receiver of cognitive BS. In the proposed scheme, the cognitive BS has a uniform circular array (UCA) with 8 elements, it can provide five nearly orthogonal sectors for MSs, and a base-band channel can be shared by 5 sectors, but the MS has one omni-directional antenna only, and simple transmitter and receiver. The experimental results verify that the proposed algorithms are able to increase the cellular capacity to nearly 5 times with low co-channel interference, and the co-channel interference also can be canceled by LDPC codec.Maximising the cognitive radio capabilities of adaptive radio antennas
http://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0182
The following topics are dealt with: cognitive radio; adaptive radio antennas; parasitic antenna arrays;MIMO transmission; compact antenna arrays; tunable antenna array; wireless networks; ESPAR antenna arrays; PSK modulation schemes; BPSK; spatial spectrum sensing; wireless handheld terminals and capacity allocation problem. (49 pages)A method of angle error extraction for monopulse radar with 3-subarray variable polarization antenna
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1251
To improve the ability of radar's anti-jamming and target recognition, polarization technology is applied to monopulse angle measurement. 3-subarray millimetre wave variable polarization array antenna is also proposed and discussed in this paper. A novel method of angle error extraction in horizontal and vertical direction is given by analyzing polarization synthesis and electric field of the antenna, meanwhile, the difference between the new method and traditional one is discussed. Finally, according to the new method, simulation results of angle error extraction are presented.Controllable pattern of conformal antenna array by the hybrid genetic algorithm
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0164
Controllable radiation pattern of 5 × 11 conformal antenna array is optimized by a hybrid genetic algorithm (HGA), which composes of the simplified quadratic interpolation (SQI) method and a real-coded genetic algorithm (RCGA). It is considerable to use this hybrid genetic algorithm to optimize amplitude weights of the elements to satisfy specified deep notches, nulls and average side-lobe level. It appears to be effective to use the HGA to compensate the mutual coupling effects on the single element pattern for the conformal antenna array. (4 pages)Integrated design and research of novel KA-band circular polarized monopulse interrogator array antenna
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0459
This paper presents a scheme of novel electrically large monopulse circularly polarized interrogator array antenna, which works at Ka-band. A hybrid algorithm based on MoM (Method of moment) for electrically large array design is studied, in which the function of optimizing the puncture rate is contained. A novel 2×2 circular polarized sub-array is designed, which improves the axial ratio performance of whole array. The computation results of antenna performance have achieved the anticipated goal, and been verified by experiment. (4 pages)Compact microstrip array antenna with a squint beam
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1881
A compact X-band microstrip array antenna with a squint beam is introduced without matched load. Experimental and simulated results are in good agreement. Its measured beam is at 10 degree offset to the broadside with a measured gain of 12.2 dB at 10 GHz. The impedance bandwidth (VSWR2) of 15% is measured. It is a wideband design with compact simple structure, suited for fuze application.DOA estimation algorithm for conical conformal array antenna
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0300
The pattern of every element in conformal array has a different direction because of the curvature of conformal carrier, which results in polarization diversity of conformal array antenna, therefore polarization parameters and DOA (Direction-Of-Arrival) of incident signals are contained in observations. Consequently it is usually required that the polarization parameters and DOA of incident sources are jointly estimated. A blind DOA estimation method with respect to polarization diversity is proposed on the basis of ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) algorithm for conical conformal array antenna, in which three pairs of special subarrays are designed. Azimuth and elevation angles of sources are found without knowing the polarization parameters by decoupling them. Then the CRB (Cramer-Rao Bound) of this method is derived and the validity of this algorithm is confirmed by Monte Carlo computer simulations. (4 pages)Planar waveguide antennas for millimeter-wave systems
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1377
Planar waveguide arrays are promising candidates for high gain, high efficiency antennas in millimeter-wave systems. Authors are driving forward a 5 year project on "RF coexisting technology on high speed baseband IC for millimeter wave radio systems" which is supported by Ministry of Internal Affairs and Communications (MIC) funding as well as Industry' s participation. This paper introduces the project and the planar waveguide antennas which characterize it. Among various activities in the project, bandwidth enhancement of the series fed hollow waveguide arrays as well as the loss estimation of the post-wall waveguide antennas are discussed in detail.Millimeter wave radar for millimter wave/infrared dual mode sensor
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0197
A Ka-band millimeter wave radar system for one special configured millimeter wave and infrared dual mode sensor is developed. It employs stepped frequency and pulse doppler signal waveforms so that it can detect both stationary targets and moving targets. It adopts special microstrip array antenna with central aperture, four channel transmit/receive module and RF monopulse comparator. It can achieve higher transmit gain and accomplish lower noise figure and higher receiver sensitivity. Furthermore, the experiment results are given which indicate that the dual mode sensor can be applied to short range seeker. (3 pages)Appropriate random phase feeding technique forsatellite-communication-on-the-move
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0407
Resolving the side lobe level deterioration of the antenna is a key technology on the satellite-communication-on-the-move (SOTM). Aiming at improving the performance of the multi-panel phased array antenna for SOTM we analyzed its characteristics and the phase quantization error. The appropriate random phase feeding technique based on the genetic algorithm (GA) is proposed. It applied the GA to optimize phase weightings of sub-arrays. And the phase quantization errors are transformed nonperiodic errors. In simulation results compared with rounding method it provides steady and optimal random phase distribution to the multi-panel phased array antennae and it effectively decreases the side lobe level of the antenna pattern. (4 pages)Coincidence of the Rao test, Wald test, and GLRT of MIMO radar in gaussian clutter
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0387
This paper deals with the problem of detecting signal with MIMO radar in correlated Gaussian clutter with known covariance matrix. The general MIMO model, with widely separated sub-arrays and co-located antennas at each sub-array, is adopted. It is proved that the Rao test and the Wald test coincide with generalized likelihood ratio test (GLRT). (4 pages)Design of a wide-band conformal phased array antenna with aperture-coupled antenna
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0165
A wide-band 9×4 conformal phased array antenna is designed with the aperture-coupled antenna in this paper. The array is assembled with 9 linear arrays. The elements in the each linear array are fed via apertures by a feed network which is integrated with the array. The proposed conformal antenna is easy to fabricate. Meanwhile, the elements are shielded with a dielectric layer on them. The measured result of the center embedded linear array shows the bandwidth over 20% (VSWR<2.0) and the cross-polarization level is below -20dB. (3 pages)Integrated waveguide slot antenna for V-band based on LTCC technology
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1283
A design of LTCC multi-layer slot antenna is introduced, which is based on classical design theory of slot antenna and LTCC technology. According to full-wave electromagnetic(EM) simulation, the antenna, intended for use in high integrated 60 GHz radios, has achieved an acceptable impedance bandwidth from 53 GHz to 70 GHz and a peak gain of 5.2 dB at 68.5 GHz.Capacity estimation of HF-MIMO systems
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0033
Multiple input multiple output (MIMO) systems utilize multiple antennas at both the transmitter and the receiver. This paper describes some recent experimental work that has been carried out in order to investigate the feasibility of applying MIMO techniques within the high frequency (HF) band. It is a significant development because the potential increase in data rates will benefit not only the existing HF radio systems but also open this band to new low cost communication applications. The capacity estimates for systems employing multiple antennas at the transmitter and receiver in the HF band are computed. Specifically a comparison is made between MIMO configurations employing homogenous antenna arrays and collocated antenna arrays in terms of their envelope correlation and capacity. The results indicate that the HF band can be used for MIMO applications and that compact collocated antennas can replace large homogenous arrays to provide potential capacity gains.Preconditioned adaptive integral method for the analysis of planar microstrip structures
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1366
Adaptive integral method based on far-field expansion is introduced to speed up the analysis of the planar microstrip structure. The auxiliary basis functions are constructed as superposition of point-like current elements located on rectangular grids which reproduce the same far field as generated from the original basis functions. Then it is able to employ the fast Fourier transform technique to speed up the matrix vector multiplication required by the iterative solver. The resultant linear systems are then preconditioned by the symmetric successive over relaxation technique to further accelerate iteration. Compared to the previous scheme, the proposed algorithm makes a reduction in both the computational complexity and the storage requirement to attain the same precision.Compact antenna arrays for HF MIMO applications
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0034
This paper describes the practical development of compact antenna arrays to support the investigation of MIMO systems exploiting ionosheric propagation in the HF band. Three candidate arrays have been developed for receiver applications based on active electronics to provide broadband non-tuned operation with electrically small receiving elements. A crossed resonant loop is under development for use as a transmitting antenna. Transmission results demonstrating the operation of the antennas is included.Exact modeling and computation using MLFMA of an antenna array with a radome structure
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1277
The exact model of an antenna array with a dielectric radome is established by using the surface integral equations (SIE) and method of moments (MoM). The multilevel fast multipole algorithm(MLFMA) is used to reduce the memory occupation and accelerate the iteration convergence of the conjugate gradient (CG) method. Based on the validation of the correctness of the algorithm, some electrically large antenna-radome system are numerically simulated, and their radiation characteristics are analyzed.Research of the ambiguity restraint in five-element cross-shaped array
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1255
The ambiguity problem of direction of arrival (DOA) estimation in uniform cross-shaped array is caused by the large element-spacing. From the viewpoint of matrix, the ambiguity can be described as the complete equality of the steering-vectors generated by the estimated false angle and true angle. In order to break the balance, which the steering-vectors generated by the false and true angle are completely equal, a novel method is proposed, in which an additional element with small spacing to the origin is added in the five-element uniform cross-shaped array. From the results of mathematical analysis and simulation, it is found that the method proposed can revise the steering-vector, restrain the false peak and improve the accuracy of DOA estimation greatly.Development of microwave hermetic packages using cavity in LTCC for phased-array antenna
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0142
Low temperature co-fired ceramics (LTCC) cavity technique is an excellent packaging solution to realize integration of microwave interconnecting substrate and packaging house with lower cost for developing microwave multichip modules (MMCMs) for phased-array antennas. Development of microwave hermetic packages with LTCC cavity structure was described in detail in this paper. The microwave LTCC cavity structures were analyzed, and the LTCC cavity transition structures were simulated and optimized by using the microwave analysis software. The manufacturing process for LTCC cavity was studied and the microwave hermetic packages using LTCC cavity was developed successfully. Good agreement was acquired between the simulated results and the experimental results. (4 pages)Suppressing cosite interference of shipboard antennas using AIC technology
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1288
Based on the characteristics of cosite coupling interference between transmitting and receiving antennas in a same battleship, this paper analyses the principle of interference suppression using adaptive interference cancellation (AIC) method, and describes an implementing scheme. At last, an experiment programme and some results are provided to demonstrate the effectiveness of the AIC system. Experiment results prove that an interference cancellation rate (ICR) about 40 dB can be achieved using this method.A millimeter wave variable polarization monopulse frontend based on microstrip array antenna
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1317
A millimeter-wave variable polarization monopulse frontend based on microstrip array antenna is presented in this paper. The front-end consists of four millimeter wave T/R modules and a microstrip antenna with four linear polarized subarrays. The polarization of far field electric field can be configured by amplitudes and phases of the feeds. Besides the angle error of monopulse angle estimation, the polarization information of the target can be also obtained simultaneously. Digital controlled phase shifters are used to configure the phases of feeds and to change the polarization of radiation pattern. Digital virtual polarization synthesis and digital monopulse sum-difference are realized in digital processing module.Research on transition matrix between nonstandard polarization base defined by a polarimetric radar and HIV polarization base
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0140
Transition matrix between non-standard polarization base defined by a kind of variable-polarization radar and standard orthogonal polarization base is deduced.The electric field with expected polarization can be synthesized in space by multi-polarimetric millimetre wave array antenna.The transition matrix established the relation between amplitude and phase of feed of every subarray and the expected- polarization electric field in far zone. The transition matrix can be regarded as algorithmic support for variable- polarization radar to realize virtual polarization synthesis and polarization agility. Finally, the algorithm is proved right and useful by presenting simulation results of far zone electric field of 3-element and 5-element radar array antenna. (3 pages)System errors analysis and correction of “one-active” LASAR expermient
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0216
“One-active” LASAR is a kind of linear array 3-D image SAR system that only one element of the linear array is active at every footprint. This paper will analyze three major system errors presented in the “one-active” LASAR experiment, which is startup synchronization error, PRF error and obliquity error, and introduce a method to correct them. The analysis and correction are supported and proved by experiment results. (4 pages)A novel MMW active monopulse antenna for angle measurement
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0342
A novel ring-shaped MMW active monopulse antenna suited for MMW/IR dual-band radar application is proposed. The microstrip array antenna including four subarrays has been chosen. Each subarray is connected with a separate T/R making a four-element active antenna. The merit of increasing the power transmitted and the receiver's sensitivity make the gain both the transmitting and receiving antenna higher, which make the angle measurement system's performance better. The radiation patterns of the active antenna was measured and the results show its superiority compared to the traditional one. The experiment was done for angle measurement using the active system. The results showed its validity and practicability. (3 pages)A research on synthesis processing of orthogonal array radar based on non-linear frequency modulated signals
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0336
Orthogonal array radar OAR is a new radar system. This paper introduces the principles of the OAR. Since the array elements of the OAR transmit orthogonal signals in the omni-direction at the same time, after the signals in different channels are received, the signal synthesis can form the transmitting beam and obtain a narrow pulse. If each transmitting signals are single frequency signals and the multiplied product of the time width T of the transmitted signals and the frequency interval Δf between each signal is larger than 1, the distance grating lobe will occur after the signal synthesis. To reduce sidelobe level, increase the ratio of mainlobe and sidelobe (RMS) and eliminate the distance grating lobe effectively, the method using the non-linear frequency modulated (NLFM) signal as the transmitting signal is presented in this paper. The analysis result shows that this method is effective to solve these problems. (4 pages)Performance of smart antenna receivers implemented in different frequencies
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.2030
The performance of directional RAKE receiver (DIRAKE) implemented in radio frequency, intermediate frequency and baseband is investigated as well as the numerical results. The DIRAKE is based on the smart antenna (SA) and traditional RAKE receiver, which results in the separation of signal from space domain. It is shown in the paper that the scheme of intermediate frequency has the highest performance cost, by which the multi-path interference can be restrained. For coherent demodulation unusable in baseband, interference would be amplified, which results in the fluctuation of performance. Though the performance of radio frequency scheme is best, it is too hard to realize in engineering.Deployment design and simulation of hybrid bistatic radar
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0124
According to the clutter characteristic of spaceborne bistatic radar, better clutter characteristic can be achieved in the space-airborne bistatic radar after good deployment of satellite-plane flight status. The deployment mode of space-airborne bistatic radar is presented based on the state of side-looking receiving antenna array and bistatic baseline in order to get better clutter characteristic. Simulations have been done based on the principle of bistatic deployment mode, the results show that the spaceborne bistatic radar has better bistatic clutter characteristic. (4 pages)Analysis of doublet antenna with finite frequency selective surface
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1278
In this paper, a rigorous method based on the surface integral equation is applied to analyze a doublet antenna with finite FSS radome. The surface integral equation is solved using the method of moments (MOM). The method is then used to study the effects of the finite FSS on the radiation characteristics of antenna system.Analysis and simulation on earth clutter of space-based radar
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0429
The performance of Space-Based Radar (SBR) to detect air or ground moving targets is influenced by earth clutter, so an effective algorithm to suppressing clutter can be designed if knowing the power and distribution of earth clutter. In this paper, based on the model of airborne pulse-Doppler radar, the model of SBR on power density spectrum of earth clutter in range-Doppler space is deduced, and simulated with a phased array antenna. Simulation results show the effectiveness of the proposed model. (4 pages)Research on the baseband space-frequency modulation beamforming scheme
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1989
According to the complex number expression of smart antenna (SA) array element signals and the fundamental of QPSK modulation, a mathematic model of utilizing baseband QPSK modulated signal to realize SA directional transmitting beamforming is presented. With the mathematics model, the concept of baseband QPSK space-frequency modulation beamforming is proposed as well as the circuit structure unit of space-frequency modulator. Based on the circuit unit of space-frequency modulator, the key part of baseband QPSK space-frequency modulation beamforming equipment is derived, which is fit to the directional transmission of signals of multiple CDMA subscribers.MOM analysis of the planar and curved FSS based on dipole elements
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1279
A method of moments (MOM) technique using the EFIE is described for the simulation of finitely dipole array FSS, involving both planar and cylindrically curved structures. An equivalent strip model for the wire structure is used, and RWG basis function is adopted in MOM analysis. Some characteristics of the curved FSS are studied, and the effect of mutual coupling between the FSS radome and the antenna is discussed.Beam steering characteristics and element failure compensation of spatially superposed M-ary modulation system
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1191
We present a new wireless communications system featuring a novel M-ary modulation scheme that uses spatial-power combining technology instead of two amplitude-modulated carriers in quadrature. The system incorporates multiple QPSK modulators and two-beam simultaneous transmission. Their modulator output signals are fed to power amplifiers, where each QPSK signal is separately power amplified with high efficiency. The system enables spatial superposition of two beams efficiently by using a specially tailored circular array system. One of the features in the array system is the beam steering function. We investigated the allowable beam steering angle to satisfy the required spatial superposition and showed that the spatial superposition was achieved within the range of about +/-8 degrees from the center when the two beams were steered by 10 degrees. We also investigated the effect of gain/phase setting errors evident among array elements and clarified that the spatial superposition angle of 5 degrees can be attained even when a gain setting error of 1 dB and a phase setting error of 15 degrees are evident. In addition, we studied the effect of the failure of elements constituting our system on spatial superposition and created a compensation method to maintain the performance after the elements fail. We found that our system was feasible and reliable and enabled broadband transmission with efficient use of power and bandwidth. (8 pages)