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In many practical applications, sensor array elements fail for a multitude of reasons. They are often simplistically excluded from signal processing to avoid the deleterious effects of including them. However, depending on how many array elements fail, the performance of the array could degrade significantly which can negatively affect core array benefits such as array gain (AG) and spatial spectrum estimation. For naval vessels, failed array elements may not be replaced for a long period of time simply due to cost or maintenance schedules which can leave the array in a degraded state. This work focuses on developing a method to regain some of the lost array performance which can be applied in situ until an appropriate maintenance period. By using a higher-order ambiguity function and basis pursuit de-noising techniques, an algorithm is developed that is shown with simulated data to regain nearly all lost array performance as assessed by AG and spectrum estimate correlation when up to half of the array elements have failed.

In this paper, two practical problems that cannot be ignored when forming compactly integrated MEMS IMU array at low cost using Coriolis vibration type MEMS with low power consumption - mutual vibration interference noise caused by MEMS proximity arrangement, and outlier noise caused by random telegraph signal noise - are firstly discussed. Then, we propose an easily implementable array signal processing filtering on a small FPGA that recovers gyroscope performance (angle random walk and bias instability) by suppressing the interference noise and removing the outlier noise dynamically. We fabricated 32 consumer MEMS IMU array board without IMU screening process, implemented the proposed filter, and evaluated its performance. As a result, although there are mutual interferences and a MEMS gyro sensor with poor performance, gyroscope performance (0.7mdeg/s/√Hz as angle random walk and 0.5deg/h as bias instability) which are close to the ideal array gain of 1/√32 were successfully achieved.

Massive multiple-input multiple-output (M-MIMO) technology is considered to be a key enabling technology for future wireless communication systems. One of the challenges in effectively implementing an advanced precoding scheme to a large-scale array antenna is how to reduce the mutual coupling among antenna elements. In this paper, a new concept that is called array-antenna decoupling surface (ADS) for reducing the mutual coupling between antenna elements in a large-scale array antenna is proposed for the first time. An ADS is a thin surface that is composed of a plurality of electrical small metal patches and is placed in front of the array antenna. The partially diffracted waves from the ADS can be controlled to cancel the unwanted coupled waves. Two practical design examples are given to illustrate the design process and considerations, and to demonstrate the usefulness of ADS for the applications of phased array antennas and M-MIMO systems when commonly used precoding schemes are applied. The attractive features of ADS include its applicability to a large-scale array antenna; suitability for a wide range of antenna forms; wide decoupling bandwidth; and simplicity in implementation.

This article proposes the design of a controlled reception pattern antenna (CRPA) array with a single-layer coupled feed structure to improve the radiation gain and a matching bandwidth. Each array element consists of a feeding patch and an outer radiating loop printed on a thick ceramic substrate with a high dielectric constant. The loop is capacitively coupled to the patch and the coupling strength is adjusted by varying the gap distance. Antenna characteristics are measured in a full anechoic chamber, and an equivalent circuit is built to verify the operating principle. The results demonstrate that the proposed structure is more suitable to enhance the gain and bandwidth compared to a conventional patch antenna in small CRPA arrays.

Line-of-sight (LoS) multiple-input multiple-output (MIMO) gives full spatial-multiplexing gain when the antenna array geometry and orientation are designed based on the interterminal distance. These known design methodologies that hold for antenna arrays with fixed orientation do not provide full MIMO gains for arbitrary array orientations. In this paper, we study LoS MIMO channels with random array orientations when the number of transmit antennas used for signaling is 2. We study the impact of common array geometries on error probability, and identify the code design parameter that describes the high signal-to-noise ratio (SNR) error performance of an arbitrary coding scheme. For planar receive arrays, the error rate is shown to decay only as fast as that of a rank 1 channel, and no better than SNR $^{-3}$ for a class of coding schemes that includes spatial multiplexing. We then show that for the tetrahedral receive array, which uses the smallest number of antennas among nonplanar arrays, the error rate decays faster than that of rank 1 channels and is exponential in SNR for every coding scheme. Finally, we design a LoS MIMO system that guarantees a good error performance for all transmit/receive array orientations and over a range of interterminal distances.

Conventional antenna array synthesis methods can give good performance for uniform spaced antenna arrays within desired performance bounds. However, due to the restriction of uniform antenna element spacing, a lot of elements are required. Because of the above-mentioned drawback, in this paper, a new approach is presented to synthesise uniform spaced antenna array using the minimum number of elements. This approach introduces the state-space model to represent the desired discrete array pattern that is sampled uniformly from −1 to 1 corresponding to 0–180°, then uses the desired sampled array pattern directly to construct the forward–backward data matrix that is introduced to estimate the model parameters, from which the locations and excitations of the new antenna elements can be extracted. The appropriate roots that are located on the unit circle are selected to obtain new radiation pattern. Simulation results show the viability for both shaped-beam and pencil-beam designs.

Time and frequency modulated arrays have numerous application areas including radar, navigation, and communications. Specifically, a time modulated array can create a beampattern with low sidelobes via connecting and disconnecting the antenna elements from the feed network, while the frequency modulated frequency diverse array produces a range-dependent pattern. In this paper, we aim to introduce these advanced arrays to the signal processing community so that more investigations in terms of theory, methods, and applications, can be facilitated. The research progress of time/frequency modulated array studies is reviewed and the most recent advances are discussed. Moreover, potential applications in radar and communications are presented, along with their technical challenges, especially in signal processing aspects.

Digital beamforming with non-uniformly distributed array radar can make full use of resources and enhance the target detection capability. However, it encounters severe grating lobes and high false alarm probability. In this paper, a novel range-angle pencil-beamforming with the non-uniformly distributed frequency diverse array (FDA) is proposed. FDA is referred to as an array transmitting linearly increased carrier frequencies with the array elements. The FDA is capable of providing controllable degrees-of-freedom in range domain, which is superior to the conventional phased array. In our approach, the frequency increments and element positions are optimally determined via particle swarm optimization algorithm to focus the transmit power within a particular range and angle region. With the proposed method, the range-angle pencil-beampattern is obtained and its side-lobes in range-angle domains can be further lowered down. Numerical simulation examples are provided to verify the effectiveness of the proposed approach.

Presently certain applications demand two or more radiation patterns by using a single antenna array due to miniature and cost effective measures of the device. Hence, reconfigurable array is suitable for this purpose. This paper presents differential evolution (DE) algorithm based design of a reconfigurable antenna array. This method effectively obtains the optimum phase weights for efficient antenna performance in dual mode. The problem attempted is to find an optimal common amplitude weight distribution with minimum amplitude range ratio. 4-bit discrete amplitudes and 5-bit discrete phases have been considered to simplify the design of the array feed network. Based on simulation results, it is established that DE-based reconfigurable antenna array design provides better performance in terms of side lobe levels and null steering.

A planar linearly dual-polarized mm-wave antenna array is designed, fabricated, and investigated in detail. The requirements are two orthogonal polarizations with good purity and suitability of the array column for 1-D beamforming applications. Since single-layer fabrication without using vertical interconnection accesses is another important requirement, the chosen radiating elements are square microstrip patches, fed at two orthogonal edges. The array feeding is designed in series microstrip line fashion, providing a highly compact structure. In that way, 1-D beamforming agility is gained, when multiple array columns are arranged side by side and the individual columns are fed with appropriate phases. The sidelobe level of the array columns is decreased by implementing an amplitude taper within the series array, following the Dolph–Chebychev distribution. A fast scattering parameter calculation procedure is presented to achieve an efficient simulation and design process. The simulated and measured antenna properties are very stable over a bandwidth of 500 MHz around the center frequency proving that such a challenging dual-polarized design can be successfully implemented at millimeter-wave (mm-wave) frequencies with just one metallization layer on a grounded substrate. The design parameters and the design procedure are demonstrated in a step by step manner to give sufficient insight into the process together with the possibility of reusing the antenna array itself, as well as the underlying concepts.

A key requirement of an adaptive sensor array involves the ability to deterministically adjust the directional response of the array to reduce noise and reverberations, null interferences and enhance the gain and recognition of the desired signal. This paper presents a low-carbon adaptive broadband beamforming algorithm called the regulated-element Frost beamformer. It enhances the desired signal based on the noise conditions of the individual omnidirectional sensors deployed in a complex dynamic environment that is prone to steering errors. The investigation of this algorithm was carried out in an interference-dominant, noisy automobile environment characterised by diffuse noise conditions. An embedded system measurement of real-time signals was carried out using omnidirectional acoustic sensors mounted in a model convertible F-Type car driven at speed limits of 20 to 50 mph. The simulation results indicate an array gain enhancement of 2 dB higher than the conventional Frost beamformer and it requires less sensors and filter taps for real-time reconfigurable implementations. The experimental results reveal that the average array gain of the regulated-element beamformer is 2.9 dB higher than the conventional Frost beamformer response. The minimum floor array gain of the regulated-element beamformer is 5 dB, representing 70 % noise reduction than the conventional adaptive beamformers.

Array gain for the vertical sensor array deployed in the reliable acoustic path (RAP) is simulated in this paper. A formula is developed to evaluate the vertical array gain based on the assumption that the ocean noise is Gaussian white and isotropic. The multiple-path structure in RAP is analyzed according to amplitudes and arrival times of each propagation path. In RAP, the main components of the sound field are direct wave and once-surface-reflected wave except the region from 15km to 30km, where bottom-reflected waves cannot be ignored. In most area of RAP, simulation results show that average correlation coefficients of the vertical line array are always high along the ray path and array gains are very close to the ideal value after proper phase shift. Array gain deduction may occur at some ranges where the interaction between the sound wave and the ocean bottom cannot be ignored. It has great application prospects in target detection for the vertical line array deployed in RAP.

Spherical harmonic array processing, also known as phase mode spherical sensor array processing, has been recently studied for different communication purposes. The spherical array arrangement presents desired three-dimensional symmetry, while the phase modes provide frequency-independent spatial processing. This paper proposes two novel sensor arrangements for spherical array which have been compared with the three sensor arrangements most used in spherical array beamforming. It has been proven that these proposed arrays achieve high directivity and more symmetrical beampatterns compared to the other arrangements. The phase mode beamformer with the element space beamformer has also been analyzed in an acoustic field. Furthermore, the phase mode beamformer has been compared when using the proposed sensor arrangements where different simulations show that the phase mode beamformer, at low frequencies, suffers of a huge reduction in array gain compared to that of the element space beamformer.

A novel method for joint direction finding and array calibration in multiple-input multiple-output (MIMO) radar with unknown array gain phase errors is proposed. The transmit array and receive array are innovatively arranged along different axes, which are orthogonal to each other. After the trilinear decomposition, the influenced transmit direction matrix and receive direction matrix are combined to estimate the angles, and the gain phase errors can be calculated subsequently. The proposed algorithm is suitable for both uniform linear array (ULA) and non-ULA, and it can achieve favourable angle and gain phase errors estimation without any auxiliary sensors and any information of the gain phase errors. Furthermore, it has better estimation performance and lower complexity than the eigenstructure method. Simulation results verify the usefulness of the approach.

This paper proposes an optimum array configuration to improve null steering time for mobile controlled reception pattern antenna (CRPA) systems. The proposed array consists of a single reference element at the center and nine auxiliary elements arranged in a circular array. The array radius and the vertical positions of the center element are optimized using a genetic algorithm in conjunction with a constrained least-mean-square algorithm. The results demonstrate that the proposed array is suitable for mobile CRPA systems without significant side nulls in satellite directions.

The gain of the vertical antenna array in a randomly inhomogeneous ocean waveguide is numerically simulated on the assumption that the useful signal is generated by a finite set of mutually uncorrelated discrete spectrum modes and is received against the ocean noise background. It is shown that the choice of themost effective weight distribution of the array and the thus obtained gain strongly depend on both the modal spectra of the signal and noise and the number and position of the receiving elements in the channel. The critical factor is the mutual orthogonality of the waveguide modes at the array input, which indicates the possibility of specially arranging the elements for the known (expected) mode spectrum of the signal.

The main feature of an antenna array is its ability to form and scan the shaped main beam by using the amplitude and phase inputs as the controlling parameters at element level. In this paper, a comprehensive analysis of various parameters of a uniformly spaced linear array with respect to a number of elements for different amplitude distribution/window functions has been presented. There is a general assumption that any given window function will realize the expected parameters of the array even for a small number of array elements. A systematic study has been done to bring out very clearly the minimum number of elements that is required to realize antenna performance for a particular amplitude distribution. Effect of number of elements to obtain the desired first side lobe level and efficiency is presented. Contributions have been made to discuss the effects on directivity, gain, and beamwidth of the linear array.

We propose an aperiodic antenna array to suppress secondary radiation lobes in widely spaced arrays. We show that the use of Fermatn’s spiral as a template for the antenna array leads to similar results in terms of sidelobe level and bandwidth as those obtained by computationally expensive non-linear optimization methods. Furthermore, by maintaining the distances between neighbors approximately constant, the increase in array footprint is kept approximately within 25% of an equivalent periodic array, a key feature for space-constrained applications. Based on the straightforward computation of our method, we are able to present the results for arrays varying from 4 to 2048 elements and minimal spacing between the antennas up to ten wavelengths.

Long-range wireless power transmission (WPT) is implemented with the beamforming using the phased array transmitter technology, which has been extensively applied in the radar systems. The cost of a conventional phased array transmitter module scales up in proportion to the number of antenna elements, as the massive number of transmit channels results in the increasing complexity of hardware and feeding antenna elements. Besides, the conventional phase-shifting transmitter architecture has lower DC to RF power conversion efficiency due to the insertion loss of power combining network at microwave frequency. In this paper, the concept of spatial power combining transmitter is utilized, and the upconversion circuit is greatly simplified to an injection locked oscillator. Our WPT system is implemented with the technology of oscillator array antenna at 2.4 GHz, which converts DC power to RF power and radiates into the air directly. The feedback voltage controlled oscillator (VCO) is implemented as the microwave source using a off-the-shelf bandpass filter, and the external signal is injected to the oscillator via a microstrip coupler. The oscillator core shows the DC-to-RF conversion efficiency of 45.87% with the injected power of 0 dBm at 2.4 GHz. Then the digital phase shifter is used to phase shifting the injected signal to extend the beam coverage. From the link budget analysis, the overall DC-to-DC efficiency of our highly-integrated system shows 1.5 times (0.22%) of the conventional phased array (0.15%) when the separation between the transmit array and the receive horn antenna is 1.2 meters. Therefore, as an modularized array, the proposed system demonstrates the promising capability of upscaling to an efficient massive array with greatly reduced bill-of-materials (BOM).

A new direction-of-arrival (DOA) and power estimation method of unknown number of source signals is proposed. The direction and power of coherent and/or noncoherent signals are estimated by controlling the roots of the array polynomial on the unit circle. The genetic algorithm is used to find the phases of the array polynomial roots that minimize the array output power. The pseudo-spectrum is obtained by phase rotation of the estimated roots, and the real power spectrum is derived from the pseudo-spectrum and the array factor. The results indicate that the direction of arrivals, power of the signals, and number of source signals are estimated from the real power spectrum.

An antenna array capable of focusing the power transmitted to a specified point in space is modeled and simulated. This array will serve best for wireless power transmission applications where one of the goals is to maximize the power transfer efficiency. The array consists of 100 dipole antennas with each antenna transmitting a sum of 50 signals where each signal has a different frequency. This difference in frequency gives an additional degree of freedom that allows the overall beam pattern to be focused to a point in space instead of just a direction. The same array structure is also capable of transmitting power to multiple points in space which is promising when it comes to powering multiple points of interest.

Array antennas are used in science as well as for commercial and military purposes. The used element antennas act in accordance to their desired uses, for example radars or stationer GPS satellites. Typical components are for example slotted waveguides, patches, yagi-antennas and helix-antennas. All these elements do stand out with their own characteristics based on their special applications. If these elements are formed into an array configuration, the effectiveness can be improved immensely. There is a relation between the array functions and the physical array properties like the element alignment (linear, planar, circular), distances between the elements and so on. Among the physical properties there are other attributes like phase or amplitude coefficients, which are of great significance. The aim of this study was to provide an insight into the problem of array design, as far as the antenna element phase is concerned. Along with this, array radiation characteristics effects are presented. With the help of the extracted cognitions beam forming behaviour can be shown and the array phase behaviour can be analysed. One of the main applications is to simulate the array characteristics, like the radiation characteristic or the gain, for displacements of the array feeding point. A software solution that simulates the phase shift of a given array pattern is sought to adjust the feeding point.

While transmit and receive beamforming for the multiple-input multiple-output (MIMO) point-to-point channel is a well-studied topic, existing algorithms cannot specify effective beamformers for certain situations. To address this deficiency, we present an iterative algorithm that can establish beamformers based on different channel information available to the transmitter and receiver, different receiver architectures, and different constraints on the power radiated by the transmit array. Simulation results based on modeled and measured channels demonstrate that the algorithm effectively accommodates a wide range of conditions and that the performance achieved with the approach matches that obtained using existing algorithms that are applicable only to specific conditions.

An array is constructed to radiate the far-field pattern of a single complex point source. For any nonzero error tolerance, the physical dimension of the array is smaller (sometimes much smaller) than the diameter of the branch-cut disk of the complex point source. The inverse source problem is formulated for non-resonant arrays with reactive zones that do not extend significantly beyond the physical dimensions of the array. Both time-harmonic and pulsed beams are considered. In numerical examples, each array element consists of real point sources in an end-fire configuration.

A new array synthesis problem, whose objective is to maximize secure information shared with a legitimate recipient in the presence of a passive eavesdropper, is posed for line-of-sight (LOS) wireless transmission. By casting the problem into the form of a semidefinite program, it is found that the problem is convex and that optimal solutions can be efficiently found irrespective of the array topology. Representative results for a uniform linear array (ULA) and uniform circular array (UCA) are presented to demonstrate the utility of the method. Furthermore, it is shown that the radiated power of the optimal solution can be naturally decomposed into a signal pattern and noise pattern , providing an intuitive description of the optimal solutions and allowing comparison with standard array synthesis techniques.

This paper developed a uniform Y-shaped array (UYA) in a 3-dimensional (3-D) environment. While introducing electromagnetic vector sensor (EVS), the closed-form expression of spatial fading correlation (SFC) was derived. The SFC was expressed in terms of azimuth and elevation angles of arrival and the geometry of an antenna array. The developed SFC can be used to determine the covariance matrixes at both transmitter and receiver hence the capacity can be calculated in a specific channel state. This paper studied on the performance of azimuth and elevation angles of arrival, azimuth spread and elevation spread on the SFC and the capacity of a multiple input multiple output (MIMO) system. The performance comparison between antenna arrays while introducing EVS and the traditional scalar sensor array (SSA), as a uniform Y-shaped array and a uniform circular array (UCA), were made. Simulation results showed that comparing to SSA, the antenna array which introducing EVS had a significant advantage and, UCA and UYA both had its own superiorities. This investigation expanded the application of statistical channel model and optimized the study of terminal antenna array.

Recently, 3rd Generation Partnership Project (3GPP) has developed sidehaul system to cope with the explosively increasing mobile data traffic. The sidehaul system is based on single carrier-frequency division multiple access (SC-FMDA) due to its low peak to average power ratio (PAPR). Also, antenna array is designed to support multiple input multiple output (MIMO) in a restricted space. In this paper, we design the antenna array about uniform linear array (ULA), uniform circular array (UCA) and uniform planar array (UPA), and analysis the performance in sidehaul system. In addition, we propose the novel hybrid receiver full suppression cancellation (FSC) to reduce the interference from neighbor cell in sidehaul system. The proposed receiver can suppress and cancel the interference by combining interference rejection combining (IRC) with successive interference cancellation (SIC).

In a recent study by Hong Zhe Shi et al., a new approach to enhance the security of data transmission using a two-element array based on the directly modulated antenna array technique has been shown. Consequently, Hong Zhe Shi et al. have presented the phase shift values of the array to synthesise a directional modulation (DM) signal in the desired direction. In this current comment, the author demonstrates that the DM signal cannot be synthesised by a two-element phase array because the relative phase information maintain as the conventional baseband modulation signal. The DM signal synthesised using a phase array needs at least three elements.

Array error analysis and correction of active array antenna are described in this paper. Array elements composed of radiator and TR(Transmit & Recive) module have error(magnitude and phase difference among array elements) which affects SLL(Side Lobe Level). Error affectedness level depends on ideal SLL according to antenna aperture weighting, number of array elements and antenna effective aperture. To satisfy required SLL, correction of array elements is necessary; adopted differently per errors, and weighted differently per shapes of antenna and required SLL. Errors of every individual element had been defined, performance of the antenna with or without error correction had been estimated and proved through near field test.

With the rapid development of wireless communication networks, the need of massive Multiple-Input Multiple-Output (MIMO) to offer sufficient network capacity has become evident. As a part of array signal processing, direction-of-arrival (DoA) estimation is of vital importance to obtain directional information of sources and to enable the 3-D beamforming. In this paper, the performance of DoA estimation for massive MIMO systems is analyzed and compared using a low complexity algorithm. To be specific, 2-D unitary estimation of signal parameters via rotational invariance techniques (U-ESPRIT) algorithm is studied to jointly estimate elevation and azimuth information, and uniform rectangular array is selected to represent massive MIMO systems. The simulation results indicate that the U-ESPRIT algorithm works well for the massive MIMO systems. The performance has been evaluated with various types of antenna configuration and source numbers. Finally, the array resolution is adopted to analyze the performance of elevation and azimuth estimation and how to choose the appropriate antenna array configuration.

This letter investigates the array design methods of the sequential single-input–multiple-output (SSIMO) array. Antennas of SSIMO array are both transmitters and receivers, and when one antenna transmits, others receive. Compared with the widely used multiple-input–multiple-output (MIMO) array, SSIMO array has the similar azimuth resolution but lower grating lobe level (GLL). As a general rule, periodic and irredundant (PIR) ultra-wideband one-way array provides a means of improving the azimuth resolution and lowering the GLL. Based on this principle, we first propose the design method for the SSIMO array with four antennas. However, if the number of antennas exceeds four, the effective array of the SSIMO array cannot be PIR. But we have successfully proposed a novel design method to deal with this problem. The simulation results and design example verify the correctness and effectiveness of the proposed method.

Null steering in adaptive arrays is usually achieved by controlling the complex weights of all or most of the array elements. This study explores an alternative approach, where only the two side elements of the array are used for null steering. By suitably adjusting the amplitude and phase excitations of these elements, it is possible to modify the overall array pattern to place a wide angular null in the direction of undesired interfering signals. Unlike the adaptive arrays, the proposed method is much simpler in practical implementation.

Maximization of the directivity with a constraint on the lower bound of the white noise gain is a typical strategy used to attain robust performance in superdirective arrays. However, array imperfections and sensor mismatches significantly reduce the nominal directivity, even in robust designs. We focus on the generalized directivity (i.e., the directivity of the mean beam power pattern, computed using the probability density functions of the array errors) as a reliable metric to assess the average performance. We show that the generalized directivity is an extension of the nominal directivity, corresponds to the array gain when the array errors are considered, and is strictly related to the mean directivity. We demonstrate that, unlike the mean directivity, the generalized directivity of a linear array (under fair assumptions for gain, phase, and position errors) can be computed in closed form. Starting from this result, we propose a method to analytically compute, through the generalized eigenvalues, the weight vector that maximizes the generalized directivity. The numerical results confirm that maximizing the performance by setting a lower bound for the white noise gain a priori is a critical operation. Differently, maximization of the generalized directivity directly provides the optimum average performance. Notable advantages in designing maximum directivity arrays and in achieving the maximum degree of superdirectivity are reported, particularly for linear arrays steered at end-fire.

5G, the next generation of wireless communications, is focusing on modern antenna technologies like massive MIMO, phased arrays and mm-wave band to obtain data rates up to 10 Gbps. In this paper, we have proposed a new 64 element, 8×8 phased series fed patch antenna array, for 28 GHz, mm-wave band 5G mobile base station antennas. The phased array steers its beam along the horizontal axis to provide the coverage to the users in different directions. The 8×8 array contains eight 8-element series fed arrays. The series fed array is designed in such a way that it shows a mixed standing wave and travelling wave behaviour. The initial seven elements of the series fed array show a standing wave behaviour, while the eighth element shows a travelling wave behaviour. It is due to the provision of the matched inset feeding, to effectively radiate the maximum power arriving at this element. The array is operating from 27.9 GHz to 28.4 GHz with a 500 MHz impedance bandwidth. The gain of the array is 24.25 dBi while the suppression of the side lobes is −14 dB. The half power beamwidth of the array is 11.5°. The beam steering is performed which shows a stable side lobe level. The array shows a stable array gain throughout the impedance bandwidth without any beam tilting due to the variations in the frequency. The simulations are performed using both CST Microwave Studio Suite 2015 and Ansys Electromagnetics Suite 17.0 simulation packages.

In this paper, a new method of measuring the emission characteristics of phased array transmitter by receiving antenna array is proposed. Compared to traditional method that only gets the suppression of harmonic and spurious emission, the proposed method that based on direction-of-arrival (DOA) estimation and broadband sweep measurement also measures the effect of spatial power-combining which is significant for beamforming. In order to meet the measurement requirements, a receiving antenna array composed of ultra-wideband dual polarized Vivaldi antennas operating in frequency range from 1 GHz to 9 GHz is designed. The influence of mutual coupling on array response is described in detail. The validity of the method of measurement and the design of the receiving antenna array are verified by numerical calculations and measured data.

A planar controlled reception pattern array (CRPA) with increased upper hemisphere angular coverage is designed and studied. The array consists of three dual-mode TM11-TM21 circular microstrip elements. The TM11 patch is circularly polarized (CP) while the TM21 patch is dual polarized to exploit more degrees of freedom. The nulling performance of the array is studied using a Monte Carlo approach and is benchmarked against a uniform circular array (UCA) of TM11 elements and a spherical array. It is shown that for low elevation angle RFIs, the proposed array provides more angular space available for reception, compared to the planar UCA.

The delay-and-sum beamforming method (DAS) is robust, as a consequence, it is widely used in the underwater array signal processing. However, the array gain of the DAS method is limited, and is restricted to the array aperture. To tackle this problem, we propose a DAS method based on the diagonal reducing method in the data covariance matrix. Firstly, a reducing value is subtracted from the diagonal elements of the covariance matrix, so as to reduce the noise. As a consequence, a new covariance matrix includes less noise component. Then, the DAS method is applied using this new covariance matrix to obtain the beam output, and we can obtain high array gain when compared with the traditional DAS method. The analytic solution and approximate solution of reducing value are obtained under the constraint condition that the output signal-to-noise ratio (SNR) attains its maximum. The simulation and the experimental results show that the diagonal reducing method reduces some ambient noise, the output array gain is increased.

This paper presents a novel sequential transmitter phased array architecture for efficiency boosting of the transmitter-receiver link. The boost in efficiency is achieved by transmitting the signal peaks and the remaining data through different chains, each of which optimized for specific power, and recombining the signal over-the-air. Experimental results verified the over-the-air combining concept in actual environment. An 80 MHz bandwidth 802.11ac OFDM signal with 9.7dB PAPR at 5GHz was transmitted through an array of 4 patch antennas. The received EVM was lower than −38dB, similar to a uniform excited array. Simulations show that this transmitter can boost the efficiency by 31% and 54% for −8dB and −10dB power back-off from the array maximum power respectively, without any penalty in die area nor antenna size compared to a uniform array.

In antenna array thinning some antenna elements are made ‘ON’ and some antenna elements are  made ‘OFF” strategically. Keeping some of the antenna elements ‘OFF’ and reducing use of digital beamformer, desired characteristics of the array can be achieved in direct broadcast satellite (DBS) communication, to achieve higher gain and saving power utilization. In this paper, array thinning is done using differential evolution (DE) algorithm, an optimization technique. DE optimized results are compared with corresponding fully populated arrays. Lower side lobe levels (SLL) are achieved using DE optimized thinned arrays compared to fully populated arrays. Both linear array and planar are considered for array thinning.

This paper presents a high-gain low-sidelobe two-dimensional cavity-backed angled-dipole array antenna with 64 antennas in an 8 × 8 square grid for 28-GHz applications. This antenna yields broadband characteristics and similar 3-dB beamwidths in the E- and H-planes, and it is chosen for stable operation in a two-dimensional array environment. A nonuniform power distribution is used to excite the array to achieve a low sidelobe level (SLL) in the azimuth planes. The proposed array showed similar scanning performance in the E-and H-planes. It achieved gain exceeding 20.0 dBi and SLL below −18.5 dB for scanning angles up to 40°.

Microstrip Patch Array Antennas are widely used nowadays in radar satellite and other communication Systems. Use of Microstrip array as Synthetic Aperture Radar (SAR) is wide-spread these days in Airborne as well as Space Borne SAR missions. In this paper, design of a compact 128 elements Microstrip Antenna Array is discussed operating in X-Band. Designed array is high gain with total 128 radiating elements in configuration of 2×4 sub-arrays. 16 elements are single fed and constitute a single sub-array. Elements are excited using corporate feed network and have inter-element spacing of 0.6λ. Microstrip array is designed using commercially available low-loss dielectric substrate Rogers having relative permittivity ∊ r =2.2, thickness 1.575 mm and loss tangent 9 × 10−4 and simulated using Advance EM Simulator. Simulated gain of single sub-array is 17 dB while complete array has gain of 26 dB. Return Loss or S 11 of array is less than −50 dB which proves that designed array is matched to input impedance of 50Ω. As Array is in form of 2×4 sub-arrays having total 8 inputs, it can be used effectively for electronic beam steering by changing phases at input ports. Designed array is manufactured using highly precise PCB manufacturing facility and testing using far-field testing facility. Measured results are in close conformance with the simulated results.

In this paper, we consider optimum array configurations for multiple satellite signals in interference-free environment. The two measures of maximum output signal-to-noise ratio (SNR) and equal gains towards all sources incident on the array are considered for the array design. As it is computationally exhaustive to enumerate all configurations and implement eigenvalue decomposition to compare respective maximum eigenvalues, we resort to the relaxation of maximizing the lower bound of the output SNR. Subsequently, an iterative linear fractional programming method is proposed to maximize the spectral norm of the source covariance matrix. Simulation examples confirm that the array configuration plays a vital role in determining the array processing performance in interference-free scenarios. The selected optimum subarrays achieve maximum performance preservations with a dramatically reduced cost.

Smart antenna is one of the fastest emerging technologies. An antenna array is a set of individual antennas that are used for transreceiving the electromagnetic signals. In this paper weighting method is used to control the behaviour of the array along with sidelobe cancellation techniques. Three basic algorithms that are Kaiser-Bessel, Blackman and Gaussian are used to find the array weights. As a result an array factor of amplitudes 1, 0.6561, 0.2521 with side lobes which are being cancelled to yield maximum directional beam.

Objective: To design a high gain square patch array antenna, that can be applied in the communication modules to improve the system performance. The array performance will depend on the number of elements, geometry of the array and weighting vector used in the design. From array factor, we concentrated on the reception factor of the array with strong function of geometry. Methods/Analysis: Advanced array antennas generally use the planar structure for its numerous advantages. So, a planar square patch 4X4 array antenna is proposed to operate at 2.4 GHz (IEEE 802.11b) WLAN communication application in this paper. Quarter wave transformers are been used in the design to achieve impedance matching of 50 ohms. Findings: An impedance bandwidth of 20% is achieved from the proposed design. The proposed array antenna is showing gain more than 13 dB, efficiency more than 80% with good impedance matching and radiation characteristics. Novelty/Improvement: Planar structure with simple design is the novelty in this model. The improvement in the gain and directivity is unlocking the additional applications in the communication band and providing possible ways for long distance communication.

The letter describes an original time-based driving strategy of a compact antenna array suitable for future 5G Internet of Things (IoT) applications. Subsets of array elements are selectively activated in real-time for agile and precise localization of tagged objects, randomly distributed in harsh electromagnetic environments. A new layout, starting from a standard time-modulated array (TMA) solution, is implemented, which allows us to fruitfully exploit the sideband radiation capability, typical of this array family. One radiating element of the array is replaced by a multiantenna architecture, thus enabling the designer to have a total control of the maximum radiation direction of the array not only at the sideband harmonics, as for standard TMAs, but also at the fundamental. In this way, an extremely accurate localization capability is obtained by properly driving the nonlinear switches at each antenna port, without resorting to complex feeding networks or phase shifters. The antenna system design must be carried out through an accurate circuit/electromagnetic cosimulation approach, thus accounting for the electromagnetic couplings among the radiating elements and the nonlinear behavior of the switches. This is demonstrated with a compact-size planar patch array operating at 5.8 GHz compatible with portable device equipment for concurrent future wireless operations.

This paper analyzes array pattern tolerance against excitation errors. The nonprobabilistic interval analysis algorithm is used for tolerance analysis of the nonideal uniform linear array in this work. Toward this purpose, corresponding interval models of the power pattern functions are established, respectively, with the consideration of the amplitude errors, phase errors, or both simultaneously, in antenna arrays. The tolerance for the amplitude-phase error of the main function parameters including the beamwidth, sidelobe level, and the directivity is simulated by computer according to the indicators and the actual requirements. Accordingly, the worst admissible performance of an array can be evaluated, which may provide theoretical reference for optimal antenna array design. As for the problem of array synthesis in the presence of various array errors, interval analysis-convex programming (IA-CP) is presented. Simulation results show that the proposed IA-CP based synthesis technique is robust for the amplitude and phase errors.

A general linearly constrained adaptive array is examined in the weight vector space to illustrate the array performance with respect to the gain factor. A narrowband linear adaptive array is implemented in a coherent signal environment. It is shown that the gain factor in the general linearly constrained adaptive array has an effect on the linear constraint gain of the conventional linearly constrained adaptive array. It is observed that a variation of the gain factor of the general linearly constrained adaptive array results in a variation of the distance between the constraint plane and the origin in the translated weight vector space. Simulation results are shown to demonstrate the effect of the gain factor on the nulling performance.

The results of numerical simulation of an antenna array radiation pattern in impulse mode by the method of sampling phased array signal processing are represented in this paper. The studies of array parameters impact (the number of elements and the distance between them) on its penetrometer characteristics are discussed. It is established that the change of the distance among array elements leads to narrowing of the main lobe of the radiation pattern as well as to shifting of the side lobes nearer to the main one. Meanwhile, the increase in the number of elements in the array leads to narrowing of the main lobe and decreasing of the side lobes level.

This letter studies the mainlobe misorientation problem of the First-Order Steerable Differential Array (FOSDA) in the presence of microphone gain and phase errors, whose response is constructed by a linear combination of monopole and two orthogonal dipoles using a four-element square array. It is shown that the mainlobe orientation of the FOSDA will be undesiredly reversed in the presence of microphone phase errors if the array directivity controlling parameter is less than the corresponding lower bound. In contrast, the effect of microphone gain errors makes little difference when the array directivity controlling parameter varies. Some numerical examples are presented to evaluate the theoretical analysis.