TL;DR: A high-resolution imaging system based on the combination of ultrawideband transmission, multiple-input-multiple-output (MIMO) array, and synthetic aperture radar (SAR) is suggested and studied, showing a strong potential of the MIMO-SAR-based UWB system for security applications.
Abstract: A high-resolution imaging system based on the combination of ultrawideband (UWB) transmission, multiple-input-multiple-output (MIMO) array, and synthetic aperture radar (SAR) is suggested and studied. Starting from the resolution requirements, spatial sampling criteria for nonmonochromatic waves are investigated. Exploring the decisive influence of the system's fractional bandwidth (instead of previously claimed aperture sparsity) on the imaging capabilities of sparse aperture arrays, a MIMO linear array is designed based on the principle of effective aperture. For the antenna array, an optimized UWB antenna is designed allowing for distortionless impulse radiation with more than 150% fractional bandwidth. By combining the digital beamforming in the MIMO array with the SAR in the orthogonal direction, a high-resolution 3-D volumetric imaging system with a significantly reduced number of antenna elements is proposed. The proposed imaging system is experimentally verified against the conventional 2-D SAR under different conditions, including a typical concealed-weapon-detection scenario. The imaging results confirm the correctness of the proposed system design and show a strong potential of the MIMO-SAR-based UWB system for security applications.
TL;DR: This paper describes a fully integrated, low-cost 60GHz phased-array transceiver pair, implemented in 65nm standard digital CMOS and packaged with an embedded antenna array, capable of robust 10m non-line of sight (NLOS) communication.
Abstract: Recent advances in silicon technology, mm-Wave integrated circuit/antenna/package design, and beam-forming techniques at 60GHz, together with the emergence of suitable wireless standards, have enabled consumer electronics products to support wireless transmission of multi-Gb/s data such as high-definition (HD) audio/video content [1,2]. Further expansion into portable and mobile platforms will require lower power consumption, smaller form factor, and lower cost. This paper describes a fully integrated, low-cost 60GHz phased-array transceiver pair, implemented in 65nm standard digital CMOS and packaged with an embedded antenna array, capable of robust 10m non-line of sight (NLOS) communication. The array is configurable from 32 elements to 8 or fewer elements, making the transceiver pair suitable for both fixed, high-data-rate and portable, low-power applications. To enhance the robustness of the multi-element design, dynamic phase shifters allow the beam direction to be changed in real time to adapt to changing environments without interruption of the multi-Gb/s data stream. The transceiver pair supports the WirelessHD and draft 802.11ad (WiGig) standards at maximum data rates of 7.14Gb/s and 6.76Gb/s, respectively.
TL;DR: Unlike previously reported MIMO radar ESPRIT/PARAFAC-based direction finding techniques, this method achieves the rotational invariance property in a different manner combined also with the transmit energy focusing and achieves better estimation performance at lower computational cost.
Abstract: In this paper, we propose a transmit beamspace energy focusing technique for multiple-input multiple-output (MIMO) radar with application to direction finding for multiple targets. The general angular directions of the targets are assumed to be located within a certain spatial sector. We focus the energy of multiple (two or more) transmitted orthogonal waveforms within that spatial sector using transmit beamformers which are designed to improve the signal-to-noise ratio (SNR) gain at each receive antenna. The subspace decomposition-based techniques such as MUSIC can then be used for direction finding for multiple targets. Moreover, the transmit beamformers can be designed so that matched-filtering the received data to the waveforms yields multiple (two or more) data sets with rotational invariance property that allows applying search-free direction finding techniques such as ESPRIT or parallel factor analysis (PARAFAC). Unlike previously reported MIMO radar ESPRIT/PARAFAC-based direction finding techniques, our method achieves the rotational invariance property in a different manner combined also with the transmit energy focusing. As a result, it achieves better estimation performance at lower computational cost. The corresponding Cramer-Rao bound is derived and its dependence on the number of waveforms used is discussed. Simulation results also show the superiority of the proposed technique over the existing techniques.
TL;DR: In this paper, an antenna-based proximity sensor is used to detect if an external object is within a given distance of the antenna, such as a user's body, by making antenna impedance measurements, which can be used to reduce transmit powers, switch antennas, steer a phased antenna array, switch communications protocols or take other actions.
Abstract: An electronic device such as a portable electronic device has wireless communications circuitry. Antennas in the electronic device may be used in transmitting radio-frequency antenna signals. A coupler and antenna signal phase and magnitude measurement circuitry may be used to determine when external objects are in the vicinity of the antenna by making antenna impedance measurements. In-band and out-of-band phase and magnitude signal measurements may be made in determining whether external objects are present. Additional sensors such as motion sensors, light and heat sensors, acoustic and electrical sensors may produce data that can be combined with the proximity data gathered using the antenna-based proximity sensor. In response to detecting that an external object such as a user's body is within a given distance of the antenna, the electronic device may reduce transmit powers, switch antennas, steer a phased antenna array, switch communications protocols, or take other actions.
TL;DR: The synthesis of simultaneous broadside sum and difference patterns, flat-top and narrow beam patterns, and steered multibeams is enabled as assessed by a set of selected results reported and discussed to show the potentialities of the proposed method.
Abstract: In this paper, the synthesis of simultaneous multibeams through time-modulated linear arrays is studied. Unlike classical phased arrays where the antenna aperture is usually shared to generate multiple beams, the periodic on-off sequences controlling the static excitations are properly defined by means of an optimization strategy based on the Particle Swarm algorithm to afford desired multiple patterns at harmonic frequencies to make practical application of these harmonic beams which are typically regarded as an undesirable effect in time-modulated arrays. The synthesis of simultaneous broadside sum and difference patterns, flat-top and narrow beam patterns, and steered multibeams is enabled as assessed by a set of selected results reported and discussed to show the potentialities of the proposed method. Comparisons with previously published results are reported, as well.
TL;DR: In this paper, a substrate integrated waveguide fed cavity array antenna using multilayered low temperature co-fired ceramic technology is presented and designed at V-band (60 GHz).
Abstract: A substrate integrated waveguide fed cavity array antenna using multilayered low temperature co-fired ceramic technology is presented and designed at V-band (60 GHz). The 8 × 8 antenna array is designed with an enhanced bandwidth of 17.1% and a gain up to 22.1 dBi by reconfiguring radiating elements, feeding network, and the transition. The proposed array antenna also features the merits of compact size, stable performance, and high efficiency.
TL;DR: In this article, an apparatus and method for full-duplex millimeter-wave mobile wireless communication are provided, which includes a Spatial Division Duple (SDD) mobile communication system using millimeter waves.
Abstract: An apparatus and method for full-duplex millimeter wave mobile wireless communication are provided. The apparatus includes a Spatial Division Duple(SDD) mobile communication system using millimeter waves, the SDD mobile communication system including a first wireless terminal having a first transmit antenna array having a plurality of first transmit antennas for transmitting a spatially beamformed first transmit beam, and a first receive antenna array having a plurality of first receive antennas for forming a spatially beamformed first receive beam and a second wireless terminal including a second transmit antenna array having a plurality of second transmit antennas for transmitting a spatially beamformed second transmit beam directed towards a receive beam of the first wireless terminal, and a second receive antenna array having a plurality of second receive antennas for forming a spatially beamformed second receive beam directed toward the transmit beam of the first terminal.
TL;DR: The results of the two electromagnetics design problems illustrate the ability of CMA-ES to provide a robust, fast and user-friendly alternative to more conventional optimization strategies such as PSO.
Abstract: A new method of optimization recently made popular in the evolutionary computation (EC) community is introduced and applied to several electromagnetics design problems. First, a functional overview of the covariance matrix adaptation evolutionary strategy (CMA-ES) is provided. Then, CMA-ES is critiqued alongside a conventional particle swarm optimization (PSO) algorithm via the design of a wideband stacked-patch antenna. Finally, the two algorithms are employed for the design of small to moderate size aperiodic ultrawideband antenna array layouts (up to 100 elements). The results of the two electromagnetics design problems illustrate the ability of CMA-ES to provide a robust, fast and user-friendly alternative to more conventional optimization strategies such as PSO. Moreover, the ultrawideband array designs that were created using CMA-ES are seen to exhibit performances surpassing the best examples that have been reported in recent literature.
TL;DR: This paper discusses system design aspects such as antenna array design, base station and mobile station requirements, and provides system performance and SINR geometry results to demonstrate the feasibility of an outdoor mmWave mobile broadband communication system.
Abstract: Almost all cellular mobile communications including first generation analog systems, second generation digital systems, third generation WCDMA, and fourth generation OFDMA systems use Ultra High Frequency (UHF) band of radio spectrum with frequencies in the range of 300MHz-3GHz. This band of spectrum is becoming increasingly crowded due to spectacular growth in mobile data and other related services. More recently, there have been proposals to explore mmWave spectrum (3-300GHz) for commercial mobile applications due to its unique advantages such as spectrum availability and small component sizes. In this paper, we discuss system design aspects such as antenna array design, base station and mobile station requirements. We also provide system performance and SINR geometry results to demonstrate the feasibility of an outdoor mmWave mobile broadband communication system. We note that with adaptive antenna array beamforming, multi-Gbps data rates can be supported for mobile cellular deployments.
TL;DR: In this paper, a 3 × 2 microstrip antenna array is designed at a center frequency of 5 GHz with 3% fractional bandwidth and Chebyshev 0.3dB equal-ripple broadside antenna gain response.
Abstract: A new filtering microstrip antenna array is presented. The antenna elements, together with the very compact feeding network, function as a third-order bandpass filter. The feeding network, which consists of one power divider and two baluns, provides the first two stages, and the microstrip antenna elements provide the last stage in the filter design. The equivalent lumped circuit model is analyzed, and the detail synthesis procedure is presented. A third-order filtering 2 × 2 microstrip antenna array is designed at a center frequency of 5 GHz with 3% fractional bandwidth and Chebyshev 0.3-dB equal-ripple broadside antenna gain response. The results from circuit model, full-wave simulation, and measurements agree well. Compared to the conventional patch antenna array, the proposed filtering microstrip antenna array successfully suppresses the unwanted signals in out-of-band, preserves good selectivity at band edges, and retains the flatness of the passband broadside antenna gain response.
TL;DR: In this article, a method and an apparatus for aligning a phased array antenna and a phase-shifted antenna is presented. But the method is not suitable for the case of rotating a rotating receiving beam around a transmitting and receiving beam.
Abstract: A method and an apparatus for aligning a phased array antenna, and a phased array antenna are provided. A method for aligning a phased array antenna according to an embodiment of the present invention includes: receiving signals from respective antenna array subunits; performing phase shifting on the signals from the respective antenna array subunits, combining phase-shifted signals, where the signals are from the respective antenna array subunits, and obtaining a first signal, where a receiving beam corresponding to the first signal is a rotating receiving beam; rotating, by the rotating receiving beam, around a transmitting/receiving beam according to a preset angular frequency by using the transmitting/receiving beam as a rotation axis; calculating power values of respective first signals in a case that the rotating receiving beam rotates through different angles; and adjusting, according to the power values, a direction of the transmitting/receiving beam to align a phased array antenna.
TL;DR: In this paper, the authors presented a novel -band wideband circularly polarized 64-element microstrip antenna array with double application of the sequential rotation feeding technique, which can find good applications in aerospace, radar, and communication systems.
Abstract: A novel -band wideband circularly polarized 64-element microstrip antenna array is presented in this letter. It is developed with double application of the sequential rotation feeding technique. The array employs corner-truncated microstrip patches as the basic element, and then a four-element array as the subarray. By applying the sequential rotation technique twice to design the feed networks, a full 64-element array with good performance is obtained. A prototype of the full array was constructed and tested. The measurement results show that both the reflection coefficient of less than 10 dB and axial ratio of less than 3 dB have been achieved over a frequency band of 27-31 GHz; this corresponds to a wide bandwidth of 13.8%. Due to its planar configuration, the proposed array can find good applications in aerospace, radar, and communication systems.
TL;DR: The proposed antenna system is suitable for a wide range of applications, such as wireless high definition video/audio, USB and firewire replacement, Frequency Modulated Continuous Wave (FMCW) radar, and home/office backhaul application at millimeter-wave frequency.
Abstract: The limited coverage of wireless communication at the millimeter-wave frequency band due to large free-space path loss, i.e. large signal attenuation, has been a major problem. Furthermore, shadowing and small-scale fading may reduce the received signal even more. An array of rod antennas is designed to tackle those problems by providing high gain, broad scan range, and a shaped beam. Each patch, which couples the electromagnetic wave to the rod, is fed by a coplanar waveguide (CPW) feedline. Each rod antenna demonstrates 18 dBi realized gain and 20° half power beamwidth (HPBW). Moreover, the 4 GHz bandwidth of the antenna provides high data rate for the gigabit wireless application. Furthermore, the Radio Frequency Microelectromechanical System (RF MEMS) switch is used to realize a switched antenna with a broad scan range. The design method and the characterization of the antenna are presented. The proposed antenna system is suitable for a wide range of applications, such as wireless high definition video/audio, USB and firewire replacement, Frequency Modulated Continuous Wave (FMCW) radar, and home/office backhaul application at millimeter-wave frequency.
TL;DR: In this paper, the design and realization of a novel wideband two-layer 4 × 4 Butler matrix in substrate integrated waveguide (SIW) technology is addressed, and the two-level, low-loss, wideband SIW transition is designed and optimized using its equivalent circuit model.
Abstract: The design and realization of a novel wideband two-layer 4 × 4 Butler matrix in substrate integrated waveguide (SIW) technology are addressed. The two-layer SIW design is exploited through a two-fold enhancement approach. The two-layer topology is first explored in a simple matrix layout with minimum number of components. A space saving design is then proposed making optimum use of the two-layer topology and the SIW technology leading to a significant size reduction. A two-level, low-loss, wideband SIW transition is designed and optimized using its equivalent circuit model. The two corresponding Butler matrix prototypes are optimized, fabricated and measured. Measured and simulated results are in good agreement. Isolation characteristics better than -15 dB with input reflection levels lower than - 12 dB are experimentally validated over 24% frequency bandwidth centered at 12.5 GHz. Measured transmission magnitudes and phases exhibit good dispersive characteristics of 1 dB, around an average value of -6.8 dB, and 10° with respect to the theoretical phase values, respectively, over the entire frequency band. The impact of the measured transmission phases and magnitudes on the radiation pattern of a 4-element antenna array is also investigated.
TL;DR: In this article, a two-layer Rotman lens-fed antenna array is demonstrated at 24 GHz aiming for an automotive sensing radar, where the layout of the lens body is placed on the bottom layer and the antennas are placed on top layer.
Abstract: This paper presents a new design to realize a compact Rotman lens-fed antenna array. The lens-fed antenna has the form of two layers, which is a new approach to reducing the size of the Rotman lens. The approach is demonstrated at 24 GHz aiming for an automotive sensing radar. The lens consists of a top metal layer, a dielectric, a common ground, a dielectric, and a bottom metal layer, in sequential order. The layout of the lens body is placed on the bottom layer and the antennas are placed on the top layer. Both of them are electrically connected through slot transitions. This two-layer structure reduces not only the total size of the lens, but also the loss of the delay lines because the lines can be designed to be as short and straight as possible. The two-layer Rotman lens-fed antenna array is measured in terms of scattering parameters and beam patterns. From the scattering parameters, the power efficiencies of the beam port 1, 2, and 3 at 24 GHz are obtained as 32.3%, 48.5%, and 50.8%, respectively. The measured beam patterns show that the beam directions are -28.1°, -14.9°, 0°, 15.5°, and 28.6° and the beamwidths are 13.4°, 13.2°, 12.8°, 13.5°, and 13.0°. The measurements confirm that the compact two-layer Rotman lens has been successfully demonstrated.
TL;DR: In this paper, a small-size integration monitoring and direction-finding antenna technology is adopted by an individual soldier backpack type radio monitoring and finding system, which is characterized in that a monitoring and directional finding antenna and a receiving process unit are integrated in the system according to the design, and spatial spectrum direction finding and correlation interferometer direction finding can be realized in one set of system.
Abstract: The utility model discloses an individual soldier backpack type radio monitoring and direction-finding system, which is characterized in that a monitoring and direction-finding antenna and a receiving process unit are integrated in the system according to the design, and spatial spectrum direction finding and correlation interferometer direction finding can be realized in one set of system. The small-size integration monitoring and direction-finding antenna technology is adopted by a monitoring and direction-finding station, the monitoring and direction-finding antenna is a foldable dipole antenna array, and five dipole unit antennas are uniformly arrayed into a circle array and are arranged in the antenna array together with five channel receivers and signal processing units. According to the design of the antenna, the influence of coupling, reflection, and the like among the antennas is prevented from integrating in the direction-finding antenna array, so that the integration level of the individual soldier backpack type radio monitoring and direction-finding system can be enhanced without influencing the performance of the antenna, thereby facilitating the use of users.
TL;DR: In this article, a 4 × 4 array of Yagi antenna using an SIW (Substrate Integrated Waveguide) feeding technique is conceived and demonstrated in the V-band.
Abstract: Millimeter wave applications such as short-range high-speed wireless links require modular, compact-size and high-directivity antennas. In this paper, high-gain compact stacked multilayered Yagi designs are proposed and demonstrated in the V-band. This novel design shows for the first time an antenna array of Yagi elements in millimeter wave stacked structure. To demonstrate the proposed concepts and design features, a 4 × 4 antenna array is created having excellent gain performance as well as very small footprint. A single element stacked Yagi antenna fed with microstrip is studied in order to obtain the desired performance. An analysis is performed to define the structure limitations. Measured results of the fabricated antenna prototypes are in good agreement with simulated results The measured Yagi antenna attains 11 dBi gain over 4.2% bandwidth with a size of 6.5 × 6.5 × 3.4 mm3. A 4 × 4 array of Yagi antenna using an SIW (Substrate Integrated Waveguide) feeding technique is conceived. Both simulated and measured results match with each other very well. The 4 × 4 array has a size of 28 × 24 × 2.4 mm3 , and reaches a measured gain of 18 dBi over 7% bandwidth. An alternate configuration of the array using angled Yagi antenna elements allows a significant improvement of the side lobe level (SLL) with a low impact on the gain performances. The proposed antennas are excellent candidates for integrated low-cost millimeter-wave and even terahertz systems. The small foot print, the antenna design flexibility as well as its easy adaptation to automatic fabrication processes are good assets for making short range portable imaging systems.
TL;DR: A multi-stage codebook design and the realization architecture to support three stages BF can create different granularity of beam patterns and realize progressive searching and simulation results show that this design can divide the beam searching to three stages searching without increasing the system complexity.
Abstract: Beamforming(BF) based on codebook is regarded as an attractive solution to resolve the poor link budget of millimeter-wave 60GHz wireless communication. Because the number of the elements of antenna array in 60GHz increases, the beam patterns generated are more than common BF, and it causes long set-up time during beam patterns searching. In order to reduce the set-up time, three stages protocol, namely the device (DEV) to DEV linking, sector-level searching and beam-level searching has been adopted by the IEEE 802.15.3c as an optional functionality to realize Gbps communication systems. However, it is still a challenge to create codebook of different patterns to support three stages protocol from common codebook of beam pattern. In this paper, we proposes a multi-stage codebook design and the realization architecture to support three stages BF. The multi-stage codebook can create different granularity of beam patterns and realize progressive searching. Simulation results for eight elements uniform linear array (ULA) show that this design can divide the beam searching to three stages searching without increasing the system complexity.
TL;DR: A mixed true second order transmission condition (SOTC) with corner edge penalty terms is developed to facilitate fast convergence in the DDM iterations to model large finite antenna arrays.
Abstract: A non-overlapping and non-conformal domain decomposition method (DDM) is presented for modeling large finite antenna arrays. Two major benefits of the proposed DDM: (a) A mixed true second order transmission condition (SOTC) with corner edge penalty terms is developed to facilitate fast convergence in the DDM iterations. Numerical experiments indicate that the convergence of DDM with the aforementioned SOTC is insensitive to the sizes of arrays; and, (b) The non-conformal property of the proposed DDM permits the use of completely independent discretization for each of the sub-domains. We demonstrate the performance of the proposed approach through several large-scale problems.
TL;DR: It is shown that, whenever a feedback delay exists, the network is not capable of offering diversity gains and source and relay power allocation results show significantly different behavior with feedback delay.
Abstract: In this paper, the decremental effect of beamforming with feedback delay on the performance of a two-hop amplify-and-forward (AF) relay network over Rayleigh-fading channels is investigated. An antenna configuration in which the source and the destination are equipped with multiple antennas, whereas the relay is equipped with a single antenna, is assumed. We derive new expressions for the outage probability and the average bit error rate (BER), which are useful for a large number of modulation schemes. To gain further insights, simple outage probability and average BER approximations at high signal-to-noise ratio (SNR) are also presented. It is shown that, whenever a feedback delay exists, the network is not capable of offering diversity gains. Furthermore, source and relay power allocation results show significantly different behavior with feedback delay. Numerical results supported by simulations are provided to show that feedback delay can severely degrade the performance of the considered AF relay system.
TL;DR: In this article, the authors present a method for estimating, for an antenna in an antenna array, interference parameters using analog signals received at the antenna on each of a plurality of subcarriers.
Abstract: Embodiments of the claimed subject matter provide methods and apparatuses for interference cancellation. One embodiment of a method includes estimating, for an antenna in an antenna array including a plurality of antennas, interference parameters using analog signals received at the antenna on each of a plurality of subcarriers. Each interference parameter is associated with one of a plurality of symbols transmitted to one of a plurality of users on one of the plurality of subcarriers. This embodiment also includes canceling interference from analog signals received by the antenna on the plurality of subcarriers using the estimated interference parameters.
TL;DR: The Banyan Tree Antenna (BTA) as mentioned in this paper is a wideband, wide-scan array that employs modular, low profile, low-cost elements fed directly from standard unbalanced RF interfaces.
Abstract: A new wideband, wide-scan array is introduced, called the Banyan Tree Antenna (BTA) array, that employs modular, low-profile, low-cost elements fed directly from standard unbalanced RF interfaces. The elements consist of vertically-integrated, flared metallic fins over a ground plane that are excited by a vertical two conductor unbalanced transmission line. The antenna resembles the bunny-ear or balanced antipodal Vivaldi antenna (BAVA) designs, but most importantly uses metallic shorting posts between the fins and the ground plane that suppress a mid-band catastrophic common-mode resonance that occurs in 2D arrays of balanced radiators fed with unbalanced feeds. This work introduces simple circuit models that describe key performance attributes of the BTA array, leading to unique physical insights and design guidelines. Simulations of infinite single- and dual-polarized BTA arrays have achieved approximately two octaves of bandwidth for VSWR <; 2.2 at broadside and VSWR <; 2.8 at scans out to θ = 45°, while maintaining better than 14 dB polarization purity at θ = 45° in the D-plane.
TL;DR: This work integrates two grid array antennas in a package; proposes the way of assembling it to the system printed circuit board; and demonstrates a total solution of low cost and thin profile to highly integrated 60-GHz radios.
Abstract: We examine the current development of highly integrated 60-GHz radios with an interest in antenna-circuit interfaces. We design and analyze grid array antennas with special attention to the differential feeding and the patterned ground plane. More importantly, we integrate two grid array antennas in a package; propose the way of assembling it to the system printed circuit board; and demonstrate a total solution of low cost and thin profile to highly integrated 60-GHz radios. We show that the package in low temperature cofired ceramic (LTCC) technology measures only 13×13×0.575 mm3 ; can carry a 60-GHz radio die of current and future sizes with flip-chip bonding; and achieves good antenna performance in the 60-GHz band with maximum gain of 13.5 and 14.5 dBi for the single-ended and differential antennas, respectively.
TL;DR: In this paper, a particle swarm optimization method based on IE3D was used to design an inset feed linearly polarized rectangular microstrip patch antenna with four element array, which is a very critical parameter which governs the resonant frequency of the antenna.
Abstract: In the recent years the development in communication systems requires the development of low cost, minimal weight and low profile antennas that are capable of maintaining high performance over a wide spectrum of frequencies. This technological trend has focused much effort into the design of a microstrip patch antenna. The objective of this paper is to design, and fabricate an inset fed rectangular microstrip patch antenna. Therefore, a novel particle swarm optimization method based on IE3D was used to design an inset feed linearly polarized rectangular microstrip patch antenna with four element array. The length of the antenna is nearly half wavelength in the dielectric; it’s a very critical parameter, which governs the resonant frequency of the antenna. In view of design, selection of the patch width and length are the major parameters along with the feed line depth. Desired patch antenna design was simulated by IE3D simulator program. Initially we set our antenna as a single patch and after evaluating the outcomes of antenna features, operation frequency, radiation patterns, reflected loss, efficiency and antenna gain, and then we transformed it to a 2x1 linear array. Then we analyzed the 4x1 linear antenna array to increase directivity, gain, efficiency, and have better radiation patterns.
TL;DR: In this article, a dual-polarized finite ORA array with octagonal ring antenna array is presented, which is based on elements formed by a triangular configuration of octagonal rings.
Abstract: A wideband dual-polarized aperture array design is presented based on elements formed by a triangular configuration of octagonal rings. The octagonal ring elements are linked by capacitors and placed a defined distance from a groundplane. A broader frequency bandwidth has been achieved by placing a further layer of conductive rings above the element rings forming a metamaterial superstrate layer. Low dielectric constant material can be used to fill the space between the array rings and the groundplane, and between the elements and the superstrate layer. A dual-polarized finite ORA array has been fabricated and measured. The octagonal ring antenna array inherently exhibits a broad scan range with a stable cross polarization performance, however in practice the cross polarization depends on the feeding arrangements. Two feeding methods are discussed with a stripline feed showing best performance.
TL;DR: This work proposes a cyclic approach to MIMO transmit array design that can be used to approximate desired transmit beampatterns and illustrates how this iterative approach can be adapted to design sparse receive antenna arrays using both vector and matrix weighting techniques.
Abstract: In active sensing applications, MIMO systems permit increased flexibility for transmit beampattern design, via waveform diversity, compared to phased-array approaches. When uniform arrays are not mandated, additional degrees of freedom for transmit beampattern design can be obtained via sparse array design considerations. Herein, we extend the motivation behind sparse receive array methodologies to that of sparse MIMO transmit array design. We propose a cyclic approach to MIMO transmit array design that can be used to approximate desired transmit beampatterns. Furthermore, we illustrate how this iterative approach can be adapted to design sparse receive antenna arrays using both vector and matrix weighting techniques.
TL;DR: In this paper, four types of EBG structures are proposed and used in the design of a patch antenna array to improve the bandwidth, gain and reduce the overall array size and the achieved bandwidth of the 2 × 2 array antenna extends from 0.5 GHz to 20 GHz.
Abstract: Four types of EBG structures are proposed and used in the design of a patch antenna array to improve the bandwidth, gain and reduce the overall array size. The four ground plane designs for the 2 × 2 microstrip patch antenna array (MPAA) are; spiral artificial magnetic conductor (SAMC) ground plane, an SAMC embedded with a large spiral artificial magnetic conductor (LSAMC), an SAMC embedded with small spiral patch cells (SSAMC), and an SAMC embedded with small spiral mushroom-type electromagnetic band-gap patches (ESEBG). Simulation results show that each configuration has its advantages and limitations. For example while LSAMC provides better response in the array size reduction and improved bandwidth, SSAMC provides better response in reflection phase and hence higher gain. The ESEBG design provides better antenna gain and bandwidth. The achieved bandwidth of the 2 × 2 array antenna extends from 0.5 GHz to 20 GHz with 85% reduction in array size compared with conventional array with normal ground plane. The array gain increased from 6.5 to 10.5 dBi and the radiation patterns are all improved when using EBG structures.
TL;DR: The joint synthesis of the spatial power pattern and polarization of arbitrary arrays is addressed and the solution to a frequently encountered problem is given to achieve a pattern that is arbitrarily upper bounded, while its polarization is optimized in a given angular region.
Abstract: The joint synthesis of the spatial power pattern and polarization of arbitrary arrays is addressed. Specifically, the proposed approach gives the solution to a frequently encountered problem, namely the array design (i.e., the determination of the radiating element weightings) to achieve a pattern that is arbitrarily upper bounded, while its polarization is optimized in a given angular region. Any state of polarization (elliptical, circular and linear) can be synthesized and there is no restriction regarding the array geometry and element patterns. The synthesis problem is rewritten as a convex optimization problem, that is efficiently solved using readily available software. This ensures the optimality of the proposed solution. Various numerical results are presented to validate the proposed method and illustrate its potentialities. The synthesis of a sequentially rotated array is first addressed. Then a linear array of equispaced randomly oriented dipoles is considered. Finally, a conformal and a planar array of patches, where the mutual coupling effects are considered, are synthesized to radiate a linear and a circular polarization.
TL;DR: A framework for modeling and analyzing a LoS link in beamspace is proposed, the key elements of the CAP-MIMO system are discussed, and results on its significant capacity advantages over two state-of-the-art designs are presented.
Abstract: We propose a new communication architecture - continuous aperture phased MIMO - that combines the elements of MIMO, continuous aperture antennas, and phased arrays, for achieving the capacity of line-of-sight (LoS) links. CAP-MIMO is based on a hybrid analog-digital transceiver architecture that employs a novel antenna array structure - a high-resolution discrete lens array - to enable a continuous aperture phased-MIMO operation with a low-complexity analog-digital interface. Our focus is on millimeter-wave (60-100GHz) LoS links for high-rate (1-100Gb/s) applications. We propose a framework for modeling and analyzing a LoS link in beamspace, discuss the key elements of the CAP-MIMO system, and present results on its significant capacity advantages over two state-of-the-art designs: i) systems that employ continuous aperture “dish” antennas for high power efficiency but no spatial multiplexing gain, and ii) MIMO systems that use discrete antenna arrays for multiplexing gain but suffer in power efficiency.