Phased Array Antenna Research Articles

A Computer Controlled Phase and Magnitude Self-Calibration Methodology for Phased Array Antennas

A Computer Controlled Phase and Magnitude Self-Calibration Methodology for Phased Array Antennas

Pencil Beams and High-Precision Aiming of Wireless Power

Wireless Power Transfer (WPT) is the technique of delivering energy to specific targets with high-gain antennas. An important global application is SpaceBased Solar Power (SBSP) in which powersats in Earth orbit gather sunlight and beam this power to terrestrial groundstations (rectennae). At the distances involved, and the power levels needed to be economical, any stray (off-axis or off-target) energy can disrupt communications, giving cause for regulatory restriction or public objection of SBSP. Until recently, sidelobe levels (SLL) were limited to no lower than -60 dB, meaning that a gigawatt beam would give off kilowatt-range SLL, leading to desensitization of communications devices for a very wide radius surrounding a rectenna. The author discovered, published, and validated a specific design for a phased array antenna (PAA) that allows SLL to be reduced to -240 dB, creating what is called a "pencil beam" with negligible off-axis energy. Studies have found that this method can be applied to PAA as small as 6 m diameter at 5.8 GHz. This breakthrough discovery was first published in 2016 but appears to have largely escaped notice by the WPT community. The second issue is aiming accuracy, with the de facto solution being phase conjugation at the transmit PAA using a pilot beam issued from the receiver. While elegant, the accuracy of angle of arrival (AOA) using phase conjugtion is limited to about 1 degree (17 milliradians). This is sufficient for 5G signals over 100s of meters, but grossly inadequate for SBSP that requires microradian pointing accuracy. A novel method to detect AOA at the microrad scale that is separated from the transmitter emission electronics allows independent optimization of both. This work presents simulation studies showing microradian capability and laboratory results in the single millirad range, a factor of 10 improvement over the current state of the art. With this new approach, an orbiting powersat can aim its beam to a terrestrial target with stability under 100 m with off-axis energy at -127 dBm (typical surface environments are -100 to -80 dBm). The combination of a pencil beam and highly-accurate AOA detection bode well for realizing the benefits of SBSP.

Wideband Simultaneous Dual Circularly Polarized Phased Array Subarray with Scalable Characteristics for Satellite Communications

This paper proposes a budget-friendly, highly integrated, and low-profile wideband simultaneous dual circularly polarized phased array subarray with scalable characteristics for satellite communications. In order to achieve wideband, the antenna unit is not only fed by double-fed point probe contact, but also by electromagnetic coupling. Moreover, the dual circularly polarized radiation of the antenna unit is realized by a miniaturized 3 dB bridge-type phase-shift network. In addition, the phased array subarray uses metalized vias to reduce inter-element crosstalk, which effectively improves the active voltage standing wave ratio (VSWR) and beam steering characteristics. Also, the subarray has interchangeability and versatility, enabling convenient two-dimensional expansion to form a tile-type phased array antenna. Besides, the phased array subarray can be used to achieve two-dimensional ±40∘ beam scanning in both the azimuth and elevation planes. Within ±40∘ beam scanning, the active VSWR of the subarray is less than 2.5 in 9.55 - 14.35 GHz (40.17%). At 12.1 GHz, the two-dimensional gain decreases by less than 2.1 dB and 1.95 dB, respectively. The proposed antenna exhibits good performance in terms of matching and beam steering characteristics, which make it suitable for use in future 5G/6G phased array antenna systems.

Broadband Beam-Scanning Phased Array Based on Microwave Photonics

A one-dimensional active broadband phased array based on microwave photonics that works in the Ku band is proposed to achieve a large instantaneous bandwidth. The phased array uses a feeding network based on microwave photonics to provide the true time delay and a wide operating bandwidth. The array is mainly composed of a broadband horn antenna, an RF transmitting/receiving module, an optical network module, and a temperature control module. The form of a horn was selected for the antenna unit, and it was fed through a waveguide to obtain a wide operating bandwidth. An optical fiber delay line that could realize the true time delay at different frequencies was adopted for the time-delay module of the optical network. To obtain a large time delay and small quantization error, a hybrid time-delay diagram utilizing electrical and optical time delays was used in the design. In addition, a temperature control module was added to the antenna system to enhance the stability of the photonic time-delay module. For verification, a prototype of the presented antenna system was designed, fabricated, and measured. The experimental results showed that the optical phased array antenna was able to scan ±20° from 12 GHz to 17 GHz, and the beam pointing did not appear to be offset over the wide operating bandwidth.

Compact planar phased array antenna for extended V2X communication coverage

In this article, a new compact planar phased array antenna is proposed for blind spot reduction in V2X communications. The proposed antenna can be easily integrated on the front-panel or rear-view side by providing 2-dimensional wide communication coverage while overcoming physical integration space limitations. Moreover, because the proposed antenna is based on a planar structure, it can be integrated effectively with beamforming circuits. To verify the proposed antenna, both single and array configurations were fabricated and compared with conventional patch antennas at 5.9 GHz. The proposed single antenna with a size of 1λ0 × 1.1λ0 × 0.02λ0 exhibited a measured bandwidth of 4.3% and a peak gain of 6.1 dBi. The measured HPBWs in the E- and H- planes were approximately 126° and 136°, respectively, compared to 75.5° and 66.9° for the conventional patch antenna. Further, the proposed antenna and reference patch antenna were extended to 1 × 8 array configurations with 8-ch beamforming circuits. The measured scan angle of the proposed antenna was 160°, compared to only 98° for the patch antenna. Finally, a vehicular communication test was conducted with 256-QAM signals, where the proposed 1 × 8 antenna array exhibited a stable error vector magnitude (EVM) over a wide coverage angle of 150°.

Efficient power management of an active phased array antenna via circular aperture reduction

Efficient power management of an active phased array antenna via circular aperture reduction

Capacity loss mitigation due to phased array antennas in multi-satellite scenarios

Capacity loss mitigation due to phased array antennas in multi-satellite scenarios

Terahertz phased array antenna based on integrated taper emitters

We report on an all-dielectric integrated taper as a radiating element for terahertz phased array antenna. The taper was manufactured on the base of the silicon substrate and was integrated with effective-medium waveguide. The obtained value of return loss of the taper emitter is 12.9 dB at a radiation frequency of 145.5 GHz. The width of the radiation pattern is 56.2° in the plane of the substrate. To demonstrate the change of the radiation pattern at different values of the phase difference between the elements of the phased array antenna, an appropriate simulation was carried out. It was found that with a phase difference between each pair of adjacent elements of a phased array antenna of 60°, the direction angle of the mainlobe of the radiation pattern changes by 5.5°. A proof of concept experimental demonstration of scanning by the mainlobe of the radiation pattern of a terahertz phased array antenna was carried out. The obtained results open up the possibility of use of the proposed taper emitter in future phased array antennas as part of a new generation communication system with ultra-high data transfer rate.

The Design and Implementation of a Phased Antenna Array System for LEO Satellite Communications.

LEO satellite constellations can provide a viable alternative to expand connectivity to remote, isolated geographical areas and complement existing IoT terrestrial communication infrastructures. This paper aims to improve LEO satellite communications by implementing a new phased antenna array system that can significantly improve the radio communication link's performance. By adjusting the progressive phase shift to each element of the antenna array system, the direction of the main radiation lobe of the phased antenna array system can be controlled with accuracy. As far as we know, it is the first time that a four-element, three-quarter wavelength phased antenna array system has been successfully realized with the intention of being optimized for implementation in LEO IoT satellite reception systems. The proposed system's high level of performance is confirmed by the measurements, which indicate effective control of the main radiation lobe orientation. The numerical analysis shows a maximum gain close to 12 dBi for about 42° elevation, a Half Power Beamwidth (HPBW) of 32° in the vertical plane, and 80° in the azimuth plane. The experimental measurement results at various main lobe orientation angles revealed an HPBW ranging from 76° to 87° in the azimuth plane and a maximum Front-to-Back ratio (F/B) of 14.5 dB.

Dual-band dual-polarized sub-6 GHz phased array antenna with suppressed higher order modes

This manuscript proposes a dual-band dual-polarized 64-element phased array antenna (PAA) with suppressed higher order modes (HoMs). Each array element is a microstrip patch structure with complementary split ring resonator (CSRR) loading, allowing for simultaneous dual-band and dual-polarization performance at 3.45 GHz and 3.87 GHz. The proposed PAA exhibits impedance matching of ≤-20\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\le - 20$$\\end{document} dB at 3.45 GHz and 3.87 GHz while limiting the mutual coupling below -19\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$- 19$$\\end{document} dB between the adjacent elements at both the operating bands. The proposed design includes a plated through hole placed near the CSRR loading to suppress any higher-order modes (HOMs). Two antenna prototypes, without and with HOMs suppression techniques are fabricated and measured. In addition, we demonstrate the beam steering of the proposed PAA up to ±600\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pm 60^0$$\\end{document} using an off-the-shelf 6-bit phase shifter module. The proposed 64 -element array achieves a gain of 23 dBi, and shows a minimal steering loss of ≃3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\simeq 3$$\\end{document} dB over the steering angle.

Coherent interface between optical and microwave photons on an integrated superconducting atom chip

Sub-wavelength arrays of atoms exhibit remarkable optical properties, analogous to those of phased array antennas, such as collimated directional emission or nearly perfect reflection of light near the collective resonance frequency. We propose to use a single-sheet sub-wavelength array of atoms as a switchable mirror to achieve a coherent interface between propagating optical photons and microwave photons in a superconducting coplanar waveguide resonator. In the proposed setup, the atomic array is located near the surface of the integrated superconducting chip containing the microwave cavity and optical waveguide. A driving laser couples the excited atomic state to Rydberg states with strong microwave transition. Then the presence or absence of a microwave photon in the superconducting cavity makes the atomic array transparent or reflective to the incoming optical pulses of proper frequency and finite bandwidth.

Discrete space-time processing in multifunctional radar systems

In radar systems, all basic tasks, from signal detection to their recognition, are solved under conditions of a priori uncertainty arising, among other things, due to natural or organized interference. The task of maintaining a balance between the speed of the information-measuring and control system and the detail of the assessment of the phase coordinates of targets is of particular relevance in modern on-board multifunctional radar systems of fighter aircraft. In such systems, all basic tasks are solved with strict restrictions on space-time resources. The purpose of the work is to analyze the options for reviewing the airspace that provide the solution of basic tasks in multifunctional radar systems with restrictions on the permissible time of observation of targets and taking into account electronic countermeasures. Based on the analysis performed using performance indicators that ensure the noise immunity of multifunctional radar systems, rational variants of a discrete space-time survey for active phased antenna arrays are proposed. In modern antennas with electromechanical scanning, two space viewing modes are used – continuous direction-finding mode and on-pass tracking. In the continuous direction-finding mode, the detail of the phase coordinate estimates is realized only for a single target, but the secrecy of the actions of the multifunctional radar system is not ensured. In the pass-through tracking mode, a high level of detail is provided for assessing the phase coordinates of targets and the noise immunity of multifunctional radar systems. Therefore, in this mode, it is advisable to evaluate only the noise immunity of multifunctional radar systems against the background of natural interference. The greatest detail of estimates of the phase coordinates of targets and noise immunity are achieved in multifunctional radar systems with active phased antenna arrays, the element base of which allows for a fast discrete space-time overview when all parameters of the electromagnetic wave change, including its polarization, according to pseudo-random laws. The use of modern onboard time standards with stability up to 〖10〗^(-18) in combination with high-speed electromechanical switches will significantly increase the detail of the evaluation of the phase coordinates of targets and noise immunity, including during group actions of aircraft. The proposed review options relate to a new priority scientific and technical direction  correction of techniques (principles, methods and algorithms) for the construction of avionics using technological advances in the development of the element base of active phased antenna arrays.

Kinematic-mapping-model-guided analysis and optimization of 2-PSS&1-RR circular-rail parallel mechanism for fully steerable phased array antennas

This paper presents a systematic methodology for analyzing and optimizing an innovative antenna mount designed for phased array antennas, implemented through a novel 2-PSS&1-RR circular-rail parallel mechanism. Initially, a comparative motion analysis between the 3D model of the mount and its full-scale prototype is conducted to validate effectiveness. Given the inherent complexity, a kinematic mapping model is established between the mount and the crank-slider linkage, providing a guiding framework for subsequent analysis and optimization. Guided by this model, feasible inverse and forward solutions are derived, enabling precise identification of stiffness singularities. The concept of singularity distance is thus introduced to reflect the structural stiffness of the mount. Subsequently, also guided by the mapping model, a heuristic algorithm incorporating two backtracking procedures is developed to reduce the mount's mass. Additionally, a parametric finite-element model is employed to explore the relation between singularity distance and structural stiffness. The results indicate a significant reduction (about 16%) in the antenna mount's mass through the developed algorithm, while highlighting the singularity distance as an effective stiffness indicator for this type of antenna mount.

Single-Layer Wideband Tilted Beam Phased Array Antenna for Millimeter-Wave Vehicle Communications

Single-Layer Wideband Tilted Beam Phased Array Antenna for Millimeter-Wave Vehicle Communications

Single-PCB Fabricated, Ultrawideband, and Wide-Scanning Phased Array Antenna With Vertically Integrated Resistive Frequency-Selective Surface

Single-PCB Fabricated, Ultrawideband, and Wide-Scanning Phased Array Antenna With Vertically Integrated Resistive Frequency-Selective Surface

Estimation of Power Density in mm-wave Phased Array Antenna for 5G Cellular Handset

Estimation of Power Density in mm-wave Phased Array Antenna for 5G Cellular Handset

A Tiling Method for Sub-Arrayed Spherical Conformal Phased Array Antennas Based on Maximum 3-D Space Entropy Model

A Tiling Method for Sub-Arrayed Spherical Conformal Phased Array Antennas Based on Maximum 3-D Space Entropy Model

Millimeter-Wave Wideband Lens Loaded Circularly Polarized Phased Array Antenna With Limited Field of View

Millimeter-Wave Wideband Lens Loaded Circularly Polarized Phased Array Antenna With Limited Field of View

A Compact and Wideband MMIC-to-Ridge Gap Waveguide Contactless Transition for Phased Array Antenna Front Ends

A Compact and Wideband MMIC-to-Ridge Gap Waveguide Contactless Transition for Phased Array Antenna Front Ends

Dual-Band and Dual-Polarized Shared-Aperture Phased-Array Antennas With Enhanced Beam Coverage for 5G FR2 and 6G FR3

Dual-Band and Dual-Polarized Shared-Aperture Phased-Array Antennas With Enhanced Beam Coverage for 5G FR2 and 6G FR3