Beam-scanning Array Research Articles

Radiation Pattern Analysis and Phase Shifter for Base Station Mobile Communication Circular Array Antenna at 900MHz Frequency by Using 4NEC2X Software

Background: This paper presents the utilization of phase shifters to manipulate and control the radiation patterns in Uniform Circular Array (UCA) antennas. UCAs, known for their 360-degree coverage and symmetrical radiation patterns, are enhanced by incorporating phase shifters, enabling dynamic beam steering and pattern shaping. Materials and Methods: A uniform circular antenna array operating at 900 GHz frequency has been intended for use in base stations using 4NEC2X simulation software. Results: A single-element dipole antenna having a 2.14 dBi gain is used as a base for constructing a uniform 0.5 λ spacing circular array. The number of elements gradually increased from 2 to 12, raising the gain to 12.3 dBi. HPBW decreased both in vertical and horizontal plans from 80o to 60o and 360o to 20o respectively this implies that the circular array antenna's directivity is enhanced. The eight-element array beam scanning was performed from 0o to 360o without any distortion in radiation pattern, gain, and directivity, contradictory with the linear array. Conclusions: The studied case and simulation output illustrate the impact of the element numbers and phase shifter configurations on properties of the radiation pattern of the uniform circular array can be obtained when increasing the number of elements, the gain increases too and scanning the main beam without any change and distortion

Full‐angle beam scanning leaky‐wave antenna array based on spoof surface plasmon polaritons

AbstractA design scheme of high‐gain and full‐angle frequency beam scanning leaky wave antenna (LWA) and array is proposed based on spoof surface plasmon polaritons (SSPPs) slow‐wave transmission line (TL) for radar field applications. A row of complementary split ring resonators is periodically etched near the SSPPs TL, which can transform the fundamental mode of SSPPs TL to the fast‐wave region and radiate electromagnetic waves, realising the full‐angle frequency beam scanning performance. A 1‐to‐2 microwave power divider is designed to feed the LWA array and realised good impedance matching covers 5.8–9.4 GHz bandwidth. Simulation and experimental results indicate that the designed LWA array can realise full‐angle beam scanning range of 180° (−90° to 90°) with a scanning rate of 3.83°/% performance. The peak gain values of the designed LWA element and array are 11.4dBi and 14.6 dBi, respectively, and the radiation efficiency of LWA array is maintained more than 80% within the operation frequency band.

A novel 4 × 4 butler matrix with continuously tunable phase covering 360° range and application for 1‐D and 2‐D beam scanning array

AbstractA novel 4 × 4 Butler Matrix (BM) with continuously tunable phase covering phase range from −180° to 180° is proposed using substrate integrated waveguide technology. The proposed BM consists of two H‐plane hybrid couplers, two E‐plane hybrid couplers and four 180° tunable phase shifters. With this simple configuration, the proposed BM can realise a continuously tunable progressive phase difference from −180° to 180° in a one‐dimensional (1‐D) or two‐dimensional (2‐D) form. For demonstration, the proposed BM has been fabricated to feed a 1 × 4 or 2 × 2 broadband microstrip antenna arrays. The fabricated prototype has a 16.7% fractional impendence bandwidth centred at 6 GHz. The measured pattern for the 1‐D array showed a continuous beam scanning range from −39° to 39° in H‐Plane, while the measured radiation patterns for the 2‐D array showed continuous beam range from −27° to 30° in elevation and 0°–180° in azimuth. The measurement results were in good agreement with the simulation results.

Active-Isolation Improvement of Shared-Aperture Beam-Scanning Array Based on Excitation Optimization Techniques

Active-Isolation Improvement of Shared-Aperture Beam-Scanning Array Based on Excitation Optimization Techniques

A Compact Broadside Coupled Stripline 2-D Beamforming Network and Its Application to a 2-D Beam Scanning Array Antenna Using Panasonic Megtron 6 Substrate.

This article presents a 4-way 2-D butler matrix (BM)-based beamforming network (BFN) using a multilayer substrate broadside coupled stripline (BCS). To achieve the characteristics of a compact, wide-bandwidth, high-gain phased array, a BCS coupler is implemented using the Megtron 6 substrate. The compact 2-D BFN is formed by combining planarly two horizontal BCS couplers and two vertical BCS couplers. The BFN is proposed without a crossover and without a phase shifter, generating phase responses of ±90° in the x- and y-directions, respectively. The proposed BFN exhibits a wide operating band of 66.7% (3-7 GHz) and a compact physical area of just 0.25 λ0 × 0.25 λ0 × 0.04 λ0. The planar 2-D BFN is easily integrated with the patch antenna radiation elements to construct a 2-D multibeam array antenna that generates four fixed beams, one in each quadrant, at an elevation angle of 30° from the broadside to the array axis when the element separation is 0.6 λ0. The physical area of the 2-D multibeam array antenna is just 0.8 λ0 × 0.8 λ0 × 0.04 λ0. The prototypes of the BCS coupler, the 2-D BFN, and the 2-D multibeam array antenna were fabricated and measured. The measured and simulated results were in good agreement. A gain of 9.1 to 9.9 dBi was measured.

A 2-D Beam Scanning Array Antenna Fed by a Compact 16-Way 2-D Beamforming Network in Broadside Coupled Stripline

A 2-D beam scanning array antenna fed by a compact 16-way 2-D beamforming network (BFN) designed in Broadside Coupled Stripline (BCS) is addressed. The proposed 16-way 2-D BFN is formed by interconnecting two groups of 4x4 Butler Matrix (BM). Each group is composed of four compact 4x4 BMs. The critical point of the design is to propose a simple and compact 4x4 BM without crossover in BCS to achieve a better transmission coefficient of the 16-way 2-D BFN with reduced size of merely 0.8λ0 × 0.8λ0 × 0.04λ0. Moreover, the complexity of the interface connection between the 2-D BFN and the 4x4 patch array antenna is reduced by using probe feeding. The 16-way 2-D BFN is able to produce the phase shift of ±45°, and ±135° in x- and y- directions. The 2-D BFN is easily integrated under the 4x4 patch array to form a 2-D phased array capable of switching 16 beams in both elevation and azimuth directions. The area of the proposed 2-D beam scanning array antenna module has been significantly reduced to 2λ0 × 2λ0 × 0.04λ0. A prototype operating in the frequency range of 4-6GHz is fabricated and measured to validate the concept. The measurement results agree well with the simulations.

K-/Ka-Band Planar Shared-Aperture Beam-Scanning Array Antenna for Simultaneous Transmitting and Receiving Low Earth Orbit Satellite Communication Terminal

A planar shared-aperture beam-scanning array antenna for simultaneous transmitting and receiving (STAR) satellite communication is proposed. The antenna operates in dual working bands with right-handed circular polarization (RHCP) from 17.7 to 21.2 GHz and left-handed circular polarization (LHCP) from 27.5 to 31.0 GHz. For the K-/Ka-band shared-aperture beam-scanning array antenna, the main challenge is to simultaneously achieve a wide beam scanning range, low profile and high cross-band isolation. Compared to high-profile end-fire duplexing or filtering antennas, planar laminated antennas have a stronger coupling between two elements operated at different frequency bands. In this design, two embedded two-stage filters are proposed and integrated into the dual-band feeders. The minimum spacing between the elements is 1/4 wavelength, and both in-band wideband impedance matching and cross-band filtering are performed simultaneously. Firstly, two square lattices with a 45° rotation angle between them and a non-stacked topology are employed in the design of uniform arrays for both bands. This design is better suited for this filtering array. Secondly, to improve CP performance during the beam scanning, the Ka-band induced current on the K-band radiator should be suppressed. The rotary feed phase and the segmented patch are used to suppress the induced current and produce the reverse induced current in the small and large beam scanning area respectively. Finally, the equivalent circuits and chain matrices are used to design the filtering feeders. As a result, the dual cross-band isolations increase to 38 dB and 41 dB. The total profile is less than 3.2 mm, much smaller than the existing K-/Ka-band filtering antenna’s profile of 10 mm, and the proposed design also has a wide operating bandwidth and a large beam scanning range of ±60°.

A simple design of reconfigurable feeding network for antenna array beam scanning

In this letter, a simple approach to design a reconfigurable feeding network (RFN) for antenna array beam scanning is presented. By combining a 3 dB power divider and a reconfigurable delay line group (RDLG), the two output signals with 2m+n sets of uniformly distributed phase gradients (PGs) can be obtained. And by adopting multi two-output RFNs and multi-stage design, a RFN for generating 2m+n continuously distributed beams is constructed. For verifying the design method, a microstrip four-output RFN for generating four scanning beams is implemented, fabricated and measured. The measured results are consistent with the theoretical analysis, which provides the validity of the design. And the design of the RFN can be used as a candidate of the feeding network for antenna array beam scanning.

A K-/Ka-band planar shared-aperture beam-scanning array with a high-isolation for the emerging mm-Wave shared-aperture terminals

A K-/Ka-band planar shared-aperture beam-scanning array with a high-isolation for the emerging mm-Wave shared-aperture terminals

Grating Lobe Suppression for Wideband Large-Spacing Beam Scanning Array Using Subarray Null Adjustable Method

In this letter, a subarray null adjustable method is proposed to solve the grating lobe problem for wideband large-spacing beam scanning arrays. With the reshaped subarray by this method, large null depths of the pattern are formed to align with the grating lobe regions. The proposed reflective phase shifter loaded four varactors adjusts these nulls continuously, accurately and flexibly. Then, a wide-angle coverage of continuous nulls sufficiently suppress grating lobes in the whole bandwith. A two-element subarray with the bandwidth of 40% (2.8–4.2 GHz) is introduced, and an 8 × 4 planar array formed by this subarray is fabricated and measured as the verification prototype. Finally, the proposed planar beam scanning array realizes grating-lobe-free scanning of ±45° in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">yoz</i> -plane (with the array spacing of one wavelength at the highest frequency) and ±53° in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xoz</i> -plane over the entire wideband range, respectively.

Circularly Polarized Corporate-Feed Beam-Scanning Array With Low Profile

A low-cost low-profile circularly polarized (CP) corporate-feed beam-scanning array is presented. As the main part of the feed network, we found that the sidewall reflection of the parallel plate waveguide (PPW) is the major reason for the deterioration of the beam-scanning performance at large angles. Therefore, a hybrid feed network composed of PPW and substrate integrated waveguide (SIW) is proposed. Mechanical beam-scanning is realized by a planar parabolic reflector-based line source generator (LSG). To expand the beam-scanning range, an SIW delay line-based phase compensation structure is introduced after theoretically analyzing the phase deviation generated by the LSG. The CP radiation is realized by improved CP antenna elements with a wide 3 dB axial ratio (AR) beamwidth. These CP antenna elements are fed by a corporate-fed network to avoid the frequency-dependent squint beam. A K-band prototype of an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times14$ </tex-math></inline-formula> array is fabricated and measured to verify the design. According to the measured results, the beam-scanning range of 0°–51° in elevation with the peak gain of 22.3 dBi is realized. The gain variation and ARs in this scanning range are less than 2.9 and 2.5 dB, respectively.

Wide-Band Wide-Beam Circularly-Polarized Slot-Coupled Antenna for Wide-Angle Beam Scanning Arrays.

The design of a wide-band wide-beam circularly-polarized slot-coupled (WWCS) radiating element for wide-angle scanning arrays (WASAs) is addressed. The WWCS radiator exploits a simple geometry composed of a primary (driven) and a secondary (passive) element to generate wide-beam patterns with rotational symmetry and high polarization purity. The synthesis was carried out by means of a customized version of the System-by-Design (SbD) method to derive a WWCS radiator with circular polarization (CP) and wide-band impedance matching. The results of the numerical assessment, along with a tolerance analysis, confirm that the synthesized WWCS radiating element is a competitive solution for the implementation of large WASAs. More specifically, a representative design working at f0=2.45 [GHz] is shown having fractional bandwidth FBW≃15%, half-power beam-width HPBWf0≃180 [deg] in all elevation planes, and high polarization purity with broadside axial ratio ARf0=3.2 [dB] and cross-polar discrimination XPDf0=15 [dB]. Finally, the experimental assessment, carried out on a PCB-manufactured prototype, verifies the wide-band and wide-beam features of the designed WWCS radiator.

A review of microwave electronically scanned array: Concepts and applications

As the application of microwave to radar and 5G communication goes wider, the array beam scanning capability has become an important and popular issue in modern society. Appropriate implementation of beam scanning methods suitable for diverse conditions could provide better performance and help to save costs for a system. Moreover, electronically scanned array has the characteristics of fast beam switching rate, high measurement accuracy and low profile. Thus, discussions on typical electronic scanning approaches are particularly necessary. This paper first presents a review of typical electronic scanning approaches to microwave arrays, such as the phased array, the focused aperture array, the frequency scanning array, and the time modulated array. And then some latest designs in the industry have been introduced. In addition, problems appeared in the application of the phased array and relevant solutions have been put forward. For the rest, some discussions are briefly summarized, as well as some comments on future trend in this field.

Metamaterial-Based Wide-Beam Dielectric Resonator Antenna for Broadband Wide-Angle Beam-Scanning Phased Array Applications

A novel metamaterial-loaded, miniaturized, broadband, wide-beam dielectric resonator (DR) antenna is presented for low-cost wide-angle beam-scanning applications. The mushroom structure is loaded on the DR structure, so the proposed DR radiator reduces the size reduction (low profile, 0.09 &#x03BB;0) and achieves a broadened bandwidth with a dual-mode response. The realized 3 dB beam-width of the DR radiator is widened from 90&#x00B0; to 194&#x00B0; by introducing a pair of miniaturized equal-amplitude and out-of-phase Huygens sources. Owing to its compact size and wide beam-width, a five-element low-cost wide-angle beam-scanning phased array is presented by using the proposed wide-beam DR elements. The measured -10 dB impedance bandwidth covers the 5G-78 band well (3.30-3.80 GHz, 14.1 %). The realized scanning angle of the fabricated linear array can be extended from &#x00B1;36&#x00B0; to &#x00B1;65&#x00B0;, and its 3 dB beam-width scanning coverage can up to &#x00B1;90&#x00B0;. In virtue of miniaturized size, wideband, low-cost, and good beam-scanning ability, the presented element, and the resulting wide-angle beam-scanning array are promising candidates for wireless communication and low-cost phased array applications.

Synthesis of Difference Patterns for 3-D Conformal Beam-Scanning Arrays With Asymmetric Radiation Aperture

Due to the asymmetry of the elements’ position distribution and polarization direction, it is a challenge to synthesize difference patterns with large slope and symmetric main-lobe on 3-D conformal beam-scanning arrays with asymmetric radiation aperture. In this article, an approach to synthesize the optimal difference patterns for 3-D conformal arrays with asymmetric radiation aperture is proposed. To determine the limitation region of the main-lobe and sidelobe for a 3-D conformal array, an initial difference pattern is generated by the joint multidimensional vector clustering method. Then, an auxiliary phase function is introduced to convert the nonconvex constraint of the symmetry of the difference beam into a convex one. Finally, an iterative convex optimization is applied to obtain the optimal difference pattern. The optimization progress is finished by extracting the vector field patterns of a simulated antenna element. Two design examples employing hemispherical conformal array (HCA) and conical conformal array (CCA) with asymmetric radiation aperture are implemented to demonstrate the effectiveness of the proposed method. Difference patterns with −20 dB sidelobe level (SLL) and large slope are obtained in both numerical and simulated results of the two design examples.

A Cross-Polarization Suppressed Probe-Fed Patch Antenna and Its Applications to Wide-Angle Beam-Scanning Arrays

In this article, H-plane cross-polarization (X-pol) radiation of probe-fed air-filled patch antennas is substantially suppressed by introducing two or more floating metal cylinders underneath the patch, respectively. The X-pol is canceled by the radiation of induced currents on metal cylinders. The working principle of the new X-pol suppressed patch (XSP) antenna is revealed by an approximate model. The X-pol level of a typical XSP antenna can be suppressed to lower than −49 and −37 dB theoretically and experimentally for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$| \theta |\le 60^{\circ }$ </tex-math></inline-formula> . Two <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times $ </tex-math></inline-formula> 8-element arrays constructed by XSP antennas and conventional patch antennas are prototyped and measured at scanning beam angles of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta = 0^{\circ }$ </tex-math></inline-formula> , −40°, and −65°. The measured co-polarization (co-pol) gain of the XSP antenna array is 0.7 and 0.9 dB larger than that of the conventional patch array at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta = -40^{\circ }$ </tex-math></inline-formula> and −65°, respectively. Besides, the beam scanning angle with −30 dB X-pol level of the XSP antenna array can be as wide as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$| \theta |\le 40^{\circ }$ </tex-math></inline-formula> , while that of the conventional patch array is about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$| \theta |\le 12^{\circ }$ </tex-math></inline-formula> . A wide-band dual-polarized XSP antenna is also presented. The measured maximum H-plane X-pol level can be lower than −29 dB within 8.7% fractional bandwidth.

Spectrum Sensing of Noncooperative Beam Signals

In this paper, we investigate the issue of spectrum sensing of noncooperative beam signals that are emitted by a multiantenna transmitter. When the sampling period of the sensing node includes the whole process of beam scanning, that is, spectrum sensing is performed in an ideal situation, we use the traditional energy detection algorithm for spectrum sensing and get good results; for multiantenna beam scanning spectrum sensing in nonideal situation, the performance of traditional energy detection algorithm is seriously degraded. To deal with this problem, a sensing period selection (SPS) algorithm is proposed. The simulation results show that the proposed algorithm can effectively improve the performance of spectrum sensing in the multiantenna array beam scanning scenario.

A Low-Profile Programmable Beam Scanning Holographic Array Antenna Without Phase Shifters

Beam scanning antenna brings new opportunities to reduce the data collision of multinode communication in the Internet of Things (IoT). This article proposes a new type antenna design scheme that can be used for IoT relay communication. A programmable beam scanning antenna without phase shifters operating in the X-band is designed to evaluate the feasibility of this scheme. The integrated design of excitation source and phase-modulated structure greatly reduces the profile of the antenna and improves the integrated degrees of freedom with other equipment. By switching the state of the PIN diode loaded on each element, different radiators can be selected and the direction of current polarization on elements can be adjusted to change the radiation phase. Furthermore, the diode states are encoded by the holographic antenna theory and controlled by the FPGA controller to realize programmable beam scanning. One-element, two-element, and 1-D array containing 32 elements are fabricated and measured. The experimental results are in good agreement with the simulation data. The operating bandwidth is 7.5% at 10 GHz while the beam scanning range of the array is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 60{^\circ }$ </tex-math></inline-formula> –60°, with a good scanning accuracy and stability. The proposed low-profile beam scanning antenna can provide stable communication services to multiple users and smart devices as a new type of beam scanning array antenna solution for the IoT application, which is beneficial to this field.

Metasurface-Based Beam Scanning Array With In-Band Co-Polarized Scattered Field Shaping

In this article, a novel array of radiation and scattering function-integrated metasurface antenna (RSIMA) elements is proposed, simulated, and measured for radiation beam scanning and two examples of in-band co-polarized (IBCP) scattered field shaping. The RSIMA consists of a slot-connected metasurface (SCMS) subarray of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times $ </tex-math></inline-formula> 3 unit cells and a substrate integrated slot waveguide (SISW). When illuminated by plane waves, each SCMS unit cell can independently obtain a wide range of reflection phases by tuning structural parameters. When excited by the coaxial port of SISW, the SCMS subarray will also act as a radiation carrier of RSIMA. Moreover, the layout change of SCMS subarray will not significantly affect the radiation performance of RSIMA. Based on the principle of phase compensation and the phase superposition method, the phase distribution for two examples of scattered field shaping can be designed. In simulations and experiments, the array of 12 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times12$ </tex-math></inline-formula> RSIMAs radiates an IBCP beam scanning over ±31.5° in the E-plane and shapes the IBCP scattered fields into a deflected vortex beam (DVB) and a deflected high-gain multi-beam (DHMB). It is worth mentioning that the SCMS layout change between two examples of scattered field shaping does not significantly affect the radiation performance of the RSIMA array.

A Low Profile, Broadband Circularly Polarized Beam Scanning Array

Based on the idea of tightly coupled dipole array, a low profile, broadband circularly polarized array is designed in this paper. The circularly polarized phased array element consists of dual polarized dipoles with the same phase center and orthogonal arrangement, grounded coupling patches, resistive frequency selective surfaces (RFSS), and a 90° phase shifter network. In order to realize broadband scanning, the effect of RFSS on the input active voltage standing wave ratio and radiation axial ratio (AR) of the element is studied. The results show that the element can operate at 5-11.5GHz, within a ±45° angle scanning range, the AR of each scanning plane is less than 3dB, and the profile height is only 0.33 λ high.