Array Beam Steering Research Articles

Flat-Panel Mechanical Beam Steerable Array Antennas With In-Plane Rotations: Theory, Design and Low-Cost Implementation

We present a compact, flat-panel phased-array antenna design that beam steers using only mechanical in-plane rotations. We explain the steering mechanism and characterize the beam analytically and numerically. Measurements of two prototype antennas for different frequencies validate the concept and modeling. The prototype designs are described in detail and feature added phase-offset control of the array elements in the aperture layout. Potential applications include low-cost and low-power flat-panel user terminals for the next generation of aerial and space communication systems.

Dual-Polarized High-Isolation Antenna Design and Beam Steering Array Enabling Full-Duplex Communications for Operation Over a Wide Frequency Range

A new dual-polarized antenna and array are presented for In-Band Full-Duplex (IBFD) applications, offering high inter-port isolation. The single-element antenna system consists of four H-shape slots, stacked patches for wide bandwidth, and two external hybrid couplers. The multilayer antenna is well matched from about 2.1 to 2.4 GHz and provides high isolation in this frequency range in excess of 60 dB. Two different prototypes are simulated and measured to highlight the design process. In addition, a new and compact hybrid coupler with excellent phase and magnitude stability is also presented for improved antenna radiation and IBFD performances. When compared to other similar types of hybrid coupler and antenna systems, the proposed configurations are simple to manufacture, provide a higher isolation bandwidth (10%), and higher gain of 7.3 dBi with cross-polarization levels of 30 dB or lower. The single-element design was also extended to a 2×2 array and studied for different beam steering and feeding scenarios. The operating bandwidths and isolation values offered by these S-band antenna and array systems can support new data link possibilities for beam steering and future low-cost IBFD wireless networks by simple antenna fabrication.

Optical phased array beam steering in the mid-infrared on an InP-based platform

Compact, lightweight, high-power beam-steering devices operating in the mid-infrared atmospheric window λ = 3 − 5 µ m are attractive for aerial-based applications such as long-range lidar and countermeasures. In the near-infrared spectral region, optical phased arrays (OPAs) have emerged as the dominant nonmechanical on-chip beam-steering technology, with a preponderance in silicon-based platforms. Extensions to the mid-infrared spectral region are scarce. Further, considering that the requirements for high performance in this region will likely demand monolithic integration with quantum cascade lasers, development of the photonic technology on a native III–V platform is advantageous. To this end, at λ = 4.6 µ m , on an InGaAs/InP platform, we experimentally demonstrate the operation of a 32-channel OPA with thermo-optic tuning for azimuthal (lateral) steering. With a waveguide spacing of 2.5 λ , we steer the beam to the maximum uninfringed field of view at ± 11.5 ∘ .

PCB-Based Design of a Beamsteerable Array With High-Gain Antennas and a Rotman Lens at 28 GHz

This letter presents a low-cost single-layer printed circuit board (PCB) design of a Rotman lens and an eight-element Yagi–Uda antenna array suitable for radio frequency (RF) beamsteering at 28 GHz. The antenna array realizes 19 dBi gain due to the guiding parasitic elements of each antenna element and a shaped ground plane surrounding the array. The array radiates in a direction parallel to the PCB enabling the possibility for two-dimensional beamsteering by stacking the PCBs. Integrated with an RF switch network, the design has seven switchable beams to the directions $-\text{30}^\circ$ , $-\text{20}^\circ$ , $-\text{10}^\circ$ , 0 $^\circ$ , 10 $^\circ$ , 20 $^\circ$ , and 30 $^\circ$ . The measured realized gain is still as high as 4–10 dBi including losses of the Rotman lens and the RF switches, thanks to the high-gain antenna array design. The array works wideband across 25.5–28.5 GHz where broadside beam gains are better than 8 dBi. This is the first letter in the literature introducing an experimentally verified design of a PCB endfire antenna array at 28 GHz including all necessary components for RF beamsteering, i.e., a Rotman lens and a switch network.

Grating lobe suppression in metasurface antenna arrays with a waveguide feed layer.

Metasurface antennas offer an alternative architecture to electrically large beamsteering arrays often used in radar and communications. The advantages offered by metasurfaces are enabled by the use of passive, tunable radiating elements. While these metamaterial elements do not exhibit the full range of phase tuning as can be obtained with phase shifters, they can be engineered to provide a similar level of performance with much lower power requirements and circuit complexity. Due to the limited phase and magnitude control, however, larger metasurface apertures can be susceptible to strong grating lobes which result from an unwanted periodic magnitude response that accompanies an ideal phase pattern. In this work, we combine antenna theory with analytical modeling of metamaterial elements to mathematically reveal the source of such grating lobes. To circumvent this problem, we introduce a compensatory waveguide feed layer designed to suppress grating lobes in metasurface antenna arrays. The waveguide feed layer helps metasurface antennas approach the performance of phased arrays from an improved hardware platform, poising metasurface antennas to impact a variety of beamforming applications.

Mutual coupling reduction by SIW ZOR elements on broadside high gain CP beam steering array

Mutual coupling reduction by <scp>SIW ZOR</scp> elements on broadside high gain <scp>CP</scp> beam steering array

A high gain pattern stabilized array antenna fed by modified Butler matrix for 5G applications

In this work, a beam-steering array antenna with the aim of pattern stabilization is presented. The antenna element consists of three-layer and a unique structure of the metalized via hole. It is capable to cover the frequency range from 20.5 to 30 GHz and a stable pattern over thorough operation frequencies. Moreover, the element has a constant gain with the peak of 9.5dBi. Additionally, the proposed modified Butler matrix consists of two 90-degree and two 135-degree couplers without phase shifting section to attain a pattern stabilized beam-steering array antenna. The proposed Butler matrix manages patterns in a constant phase over a frequency from 21 to 29 GHz with the phase error less than ±6°. The integration proposed element and feed network lead to a beam-tilting array antenna which can manage its patterns via input ports and maintain direction by frequencies variation range between 21.1 and 28.8 GHz.

Beam‐steering high‐gain array antenna with FP Bow‐tie slot antenna element for pattern stabilisation

In this work, a beam-steering array antenna for pattern stabilisation is presented. The antenna element consists of two layers with a unique structure of microstrip to coplanar waveguide (CPW) transition to cover a frequency range from 20 to 30 GHz and a stable pattern at all operating frequencies. To increase the gain of the antenna element, an elliptical broadband Fabry–Perot cavity structure is used. The element manages 3 dB gain bandwidth of almost 23–26 GHz with a 14.4 dBi peak. In addition, a modified Butler matrix consisting of two 90° and two 135° couplers without phase shift section is used to attain a stable pattern. The proposed Butler matrix performs a stationary phase with a phase error of less than ±6° over a frequency band from 21 to 29 GHz. The integration of the proposed element and feed network leads to a beam-tilting antenna capable of managing its patterns through the input ports in the operating frequency range of 20–29.5 GHz (9.5 GHz) and 20.6–29.6 GHz (9 GHz) for ports 1 and 2, respectively.

Wide‐angle 2D beam‐steering with Si‐based 16 × (1 × 16) optical phased arrays

The authors demonstrate integrated 1D optical phased arrays (OPAs) for wide-angle 2D beam-steering. The 2D OPA consists of 16 1D transversal steering OPAs whose radiators have different grating periods, to assign different longitudinal angles. The transversal steering of each OPA is performed by the phase control of the p-i-n electro-optic phase shifter array. The 1D transversal steering OPAs operate serially, changing the longitudinal radiation angle. The grating radiators were designed with an array pitch of 2 μm, and a varying period in the range of 610-710 nm. The entire 16 × (1 × 16) OPAs were integrated into a small area of 26.5 mm 2 . The obtained transversal/longitudinal beam-steering range was 46°/44°, respectively, with a wavelength of 1560 nm, which enables wide 2D beam-steering.

Design of Dual-Band Beam Switching Array for Adaptive Antenna Applications Using Hybrid Directional Coupler and E-Shape Slot Radiator

The proposed research work presents a design of a dual-band 4-element planar beam-steering antenna array with a feed network. Beam steering array is implemented with two different schemes for S-Band adaptive antenna applications. A design procedure is derived in detail, and a prototype, including the array and a planar feeding network, is built and tested for the first scheme. The array is capable to generate 4 beams in different directions based on the input applied to the port of the Hybrid Directional Coupler. Scanning range covered by this array is, in E-plane from − 45° to + 10° and in H-plane from − 25° to + 25°. Inter-element spacing is optimized with D1 = 86 mm and D2 = 40 mm to achieve maximum directive gain, which is 12.6 dBi at 3.6 GHz and 9.29 dBi at 2.4 GHz. Return Loss obtained is − 40.76 dB at 3.6 GHz and − 24.58 dB at 2.4 GHz. The planar feed network is designed with Wilkinson Power Dividers and Hybrid Directional Coupler. When the array is operated with 3.6 GHz, beam steering will be in positive directions and when it is operated with 2.4 GHz, beam steering will be in negative directions for E-Plane. Beam switching, based on the input applied to the port of directional coupler will be in the H-Plane for both frequency bands.

Design of Beam Steering-Switching Array for 5G S-Band Adaptive Antenna Applications – Part-I and Part-II

In this research work, a design of different Microwave Components for the proposed beam steering-switching array is presented. In order to achieve beam steering, two different schemes namely Beam Steering Array using Hybrid Directional Coupler and Beam Steering Array using Switched Line Phase Shifters are proposed for improvement of performance parameters like Directivity, Side Lobe Level, Beam-width, number of Maxima directions and Bandwidth. These planar microwave components are designed for 5G, S-band applications. A design procedure is derived in detail for E-Shape single element slot antenna, Wilkinson Power Divider, Hybrid Directional Coupler, Loaded Line Phase Shifter and Switched Line Phase Shifter around 3.6 GHz with necessary simulation results. For the design of beam steering array, the E-shape slot antenna is utilized with line feed and quarter-wave transformer for impedance matching. Compared to normal patch, slot antenna parameters are improved with Return Loss (S11) is −26.32 dB, VSWR is 1.08 and Directivity is 7.6 dBi at 3.6 GHz and 7.39 dBi at 2.4 GHz. Hybrid Directional Coupler parameters are, S11 is −20.83 dB, S21 is −3.39 dB, S31 is −3.56 dB and S41 is −23.78 dB. Performance parameters of Wilkinson Power Divider are, S11 is −28.65 dB, S21 is −3.46 dB and S31 is −3.46 dB. To apply phase shift for array elements, Loaded Line and Switched Line Phase Shifters using PIN diodes (MA4SPS402) are designed. For Loaded Line Phase shifter, phase of S21 with phase shifter is −53.03° and without phase shifter is −23.72°. For Switched Line Phase shifter, phase of S21 with phase shifter is 139.49° and without phase shifter is 47.03°.

Low-Profile Beam Steerable Patch Array With SIW Feeding Network

This paper presents a novel beam steerable array antenna that encompasses fully planar, low profile and lightweight characteristics for satellite communication (SatCom) applications. The proposed array contains a wideband linear source generator (LSG), an array of circular patches, and an inductive surface. The LSG is designed based on the substrate-integrated-waveguide (SIW) technology, whereas the patches are regarded as coupling circular scatterers, placed on the inductive surface for converting surface wave into the radiating wave. Each scatterer acts as a location-dependent phaser that can tailor the farfield behaviour to leverage beam steering, and is achieved by changing its distribution mechanically. A prototype of the proposed design has been fabricated and measured to evaluate the antenna performance. The measured results are in good agreement with the simulated results. The array antenna operates well with S 11 <; -10 dB in the frequency band of 10.75-12.5 GHz and has stable radiation performance with beam steering capability of nearly ±60° in the elevation plane. The total height of the proposed array is about 5.1 mm (0.19λ 0 ). It is envisaged that the proposed antenna array will empower small moving platforms due to low cost, low profile and suitability for mass production.

Beam steering with ultracompact and low-power silicon resonator phase shifters.

Photonic integrated circuit (PIC) phased arrays can be an enabling technology for a broad range of applications including free-space laser communications on compact moving platforms. However, scaling PIC phased arrays to a large number of array elements is limited by the large size and high power consumption of individual phase shifters used for beam steering. In this paper, we demonstrate silicon PIC phased array beam steering based on thermally tuned ultracompact microring resonator phase shifters with a radius of a few microns. These resonators integrated with micro-heaters are designed to be strongly coupled to an external waveguide, thereby providing a large and adjustable phase shift with a small residual amplitude modulation while consuming an average power of 0.4 mW. We also introduce near-field and far-field characterization techniques to enable the calibration and programming of resonator phase shifters in the phased array. With such compact phase shifters, we demonstrate beam steering with a 1x8 PIC phased array. The small size of these resonator phase shifters will enable low-power and ultra-large scale PIC phased arrays for long distance laser communication systems.

Holographic amplification of the diffraction angle from optical phase array for optical beam steering.

Beam steering in lidar applications presents an important engineering problem, as researchers seek to achieve the highest possible field of view with low energy cost and rapid refresh rate. Non-mechanical beam-steering technologies that exist today are known to achieve a low energy cost and rapid refresh rate, but they have a narrow angular range. A method by which the diffraction angle from a beam-steering device may be increased to cover a 4π sr solid angle is presented. Multiple holograms are recorded in the same volume hologram in a process called multiplexing. This multiplexed hologram can diffract light over a solid angle of 2π sr. To increase the angular coverage up to 4π sr, a hemispheric lens is attached to the volume hologram. Secondary holographic optical elements coated on the lens surface further diffract the light, directing it to a theoretical maximum of 4π sr. An early prototype demonstrates five distinct diffraction angles, ranging from 20° to 150°, which covers a solid angle around 90% of the entire sphere while maintaining beam collimation.

A two‐layer beam‐steering array antenna with 4 × 4 modified Butler matrix fed network for switched beam application

This paper presents a novel two layers beam-steering array antenna fed by a 4 × 4 modified Butler matrix. Each of the radiation elements have been replaced by a collection of 2 × 2 circularly polarized (CP) square patches, which joined together by a modified sequentially rotated feed network. The antenna array consists of 2 × 5 CP square patches, which connected to four ring sequential rotation and fed by butler matrix. The proposed Butler matrix which plays a role as beam-steering feed network consists of four novel 90° circular patch couplers and two 45° half circular patch phase shifter. Altogether, using of a 2 × 5 phased array antenna and a modified Butler matrix cause to empower array antenna for covering frequency range between 4.67 to 6.09GHz, the maximum gain of 14.98 dB and 3-dB axial ratio bandwidth of 1.2GHz (4.9~6.1GHz) is attained.

Design of high-speed phase-only spatial light modulators with two-dimensional tunable microcavity arrays.

Spatial light modulators (SLMs) are central to numerous applications ranging from high-speed displays to adaptive optics, structured illumination microscopy, and holography. After decades of advances, SLM arrays based on liquid crystals can now reach large pixel counts exceeding 106 with phase-only modulation with a pixel pitch of less than 10 µm and reflectance around 75%. However, the rather slow modulation speed in such SLMs (below hundreds of Hz) presents limitations for many applications. Here we propose an SLM architecture that can achieve two-dimensional phase-only modulation at high speed in excess of GHz. The architecture consists of a tunable two-dimensional array of vertically oriented, one-sided microcavities that are tuned through an electro-optic material such as barium titanate (BTO). We calculate that the optimized microcavity design achieves a π phase shift under an applied bias voltage below 10 V, while maintaining nearly constant reflection amplitude. As two model applications, we consider high-speed 2D beam steering as well as beam forming. The outlined design methodology could also benefit future design of spatial light modulators with other specifications (for example amplitude modulators). This high-speed SLM architecture promises a wide range of new applications ranging from fully tunable metasurfaces to optical computing accelerators, high-speed interconnects, true 2D phased array beam steering, and quantum computing with cold atom arrays.

A Wideband 28-GHz Transmit–Receive Front-End for 5G Handset Phased Arrays in 40-nm CMOS

This paper reports a transmit-receive (Tx-Rx) front-end (FE) in bulk CMOS targeting fifth-generation (5G) mobile user equipment (UE)-phased arrays. Block-level specifications are first reviewed based on link budget and UE array beam steering considerations, and compared against measured standalone power/low-noise amplifier and phase shifter test circuit performances. Then, the codesign of the Tx-Rx switch and antenna impedance matching is investigated for the important case of wideband dual-resonance networks, leading to a proposed topology that is experimentally verified using silicon passive test structures. A fully integrated FE prototype is fabricated in 1.1-V 1P6M 40-nm bulk CMOS and characterized in detail across digital gain and phase settings. Measurements show Tx-mode P1 dB/PAE1 dB ≥ 14.6 dBm/21.9% across 27-30 GHz, and peak Pout/PAE = 6.5dBm/8.8% at 27 GHz for an 8 x 100-MHz carrier-aggregated 64-QAM OFDM signal. In Rx-mode, a noise figure of 5.5-6 dB and an input-referred third-order intercept point of -8.5 to -6 dBm are achieved across 27-33 GHz. Normalized to area/power consumption, the achieved performance is the state of the art relative to the most recent CMOS/SiGe FEs.

Planar Beam Steerable Parasitic Array Antenna System Design Based on the Yagi-Uda Design Method

A planar beam steerable array antenna system is proposed with dual-control circuits for feeding and reactive loadings. Two orthogonally arranged planar dipoles are excited by SPDT switching circuits, while the forward and backward beam directions are controlled by the adjusted effective electric lengths of the parasitic dipole elements. The adjusted parasitic dipoles are designed to play the alternative roles of directors and reflectors based on the Yagi-Uda antenna theory. The proposed antenna system with four-way switchable beams has been implemented on a planar substrate and evaluated for orthogonal four-way beam steering performance with good agreement.

Proactive Conformal Antenna Array for Near-Field Beam Focusing and Steering Based on Curved Substrate Integrated Waveguide

The quadratic phase distribution on the antenna aperture is necessary to produce a near-field-focused (NFF) beam. The generation, as well as the steering of the quadratic phase distribution, is difficult for a series-fed NFF array antenna, especially for a large-aperture application. This is because the phase control capability of the planar series-fed beam-forming network is limited. In this paper, a curved substrate integrated waveguide (SIW) is employed as the feeding carrier to enhance the amplitude and phase control capability. The spatial placement of the SIW slot array antenna can be sufficiently used to synthesize the desired NFF beam. As examples, two kinds of proactive conformal SIW NFF slot array antennas, working in the standing-wave mode and the leaky-wave mode, have been developed. Both of them have the ability to generate the high-quality NFF beam. In addition, the proactive conformal SIW leaky-wave slot array antenna has the stable focal height over a wide steerable range. After careful analysis and design, these two kinds of antenna arrays are fabricated and proactively conformal to 3-D-printed frameworks with the desired shape. The theoretical analysis and simulated results are verified by experimental results.

Optimization of Planar Antenna Arrays Using the Firefly Algorithm

This paper describes the application of the Firefly Algorithm for the optimization of linear and planar antenna arrays. In order to demonstrate the potential of this technique, three applications are reported. The first one is the synthesis of a radiation pattern with isoflux distribution with a non-uniformly spaced linear array composed of isotropic antennas. The second application is the optimization of a non-uniformly spaced planar array composed of isotropic radiators installed on an 8-U nanosatellite. Finally, the optimization of a 3×3 planar antenna array for beam steering with simultaneous side lobe level control is described, whereby the beamforming coefficients were allowed to assume only discrete values. In the three cases considered, good agreement between the desired (mask) and the optimized patterns has been obtained.