Electronically reconfigurable beam steering array antenna using switched line phase shifter

Phased Array Antennas (PAAs), using patch -radiating elements, are projected to transmit data at rates several orders of magnitu de higher than currently offered with reflector -based systems. However, there are a number of potential sources of degradation in the Bit Error Rate (BER) performance of the communications link that are unique to PAA -based links. Short spacing of radiatin g elements can induce mutual coupling between radiating elements, long spacing can induce grating lobes, modulo 2� phase errors can add to Inter - Symbol Interference (ISI), and phase shifters and power divider network introduce losses into the system. This paper describes efforts underway to test and evaluate the effects of the performance degrading features of phased - array antennas when used in a high data rate modulation link. The system effects created by small increments in the scan angle, as would be experienced during a LEO system passing over a fixed point on the ground, have been simulated in the far field environment and analyzed. Computer simulation of the system under test has also been conducted by creating models using Matlab/Simulink. Variations of the test configuration, including a lower carrier frequency to data rate ratio and various modulation schemes, have been analyzed with these models. The results from the experimentation and simulation will be discussed and the impact for future implementations will be examined.

Fast beam steering phased-array antenna based on liquid crystal

Abstract. The antenna cross polarization suppression (CPS) is of significant importance for the accurate calculation of polarimetric weather radar moments. State-of-the-art reflector antennas fulfill these requirements, but phased array antennas are changing their CPS during the main beam shift, off-broadside direction. Since the cross polarization (x-pol) of the array pattern is affected by the x-pol element factor, the single antenna element should be designed for maximum CPS, not only at broadside, but also for the complete angular electronic scan (e-scan) range of the phased array antenna main beam positions. Different methods for reducing the x-pol radiation from microstrip patch antenna elements, available from literature sources, are discussed and summarized. The potential x-pol sources from probe fed microstrip patch antennas are investigated. Due to the lack of literature references, circular and square shaped X-Band radiators are compared in their x-pol performance and the microstrip patch antenna size variation was analyzed for improved x-pol pattern. Furthermore, the most promising technique for the reduction of x-pol radiation, namely "differential feeding with two RF signals 180° out of phase", is compared to single fed patch antennas and thoroughly investigated for phased array applications with simulation results from CST MICROWAVE STUDIO (CST MWS). A new explanation for the excellent port isolation of dual linear polarized and differential fed patch antennas is given graphically. The antenna radiation pattern from single fed and differential fed microstrip patch antennas are analyzed and the shapes of the x-pol patterns are discussed with the well-known cavity model. Moreover, two new visual based electromagnetic approaches for the explanation of the x-pol generation will be given: the field line approach and the surface current distribution approach provide new insight in understanding the generation of x-pol component in microstrip patch antenna radiation patterns.

A phased array antenna using ferroelectric coplanar waveguide (CPW) phase shifter active modules is presented based on a Ba0.6Sr0.4TiO3 (BST) thin film. The ferroelectric BST thin film was deposited on an MgO substrate by using pulsed laser deposition. The active module amplifies an RF signal with low noise and changes the phase of a received RF signal to control the main beam of the array antenna. It is composed of low noise amplifier (LNA), dc block, and ferroelectric CPW phase shifter. The prototype of 6×12 phased array patch antenna with the active modules using a ferroelectric phase shifter is proposed. The proposed array antenna continuously scanned its main beam in elevation plane to 32° from its broadside direction at 11.85 GHz by applying the continuous dc voltage to the ferroelectric phase shifter.

The present study discusses the design of microelectromechanical systems (MEMS)-based phase shifters and their application in phased array antenna (PAA) realization. Commercially available MEMS Single-Pole-Double-Throw (SPDT) switches have been employed for the phase shifter design at a frequency of 5.7 GHz (ISM band). These phase shifters are in turn integrated with the feed lines of a 4 × 1 planar patch antenna array such that electronic mode of antenna beamsteering is resulted. It has been observed that a progressive phase shift of 45° between successive patch antenna elements would generate 11° beam tilt with good directivity and a high gain of 9.5 dB. The entire PAA structure along with the antenna elements, phase shifter modules, and the corporate feed network are integrated on the same PCB laminate, Rogers Ultralam 2000™ having permittivity e r = 2.5, thickness h = 30 mil (0.762 mm), and a dissipation factor tan δ = 0.0019 in order to facilitate simplicity in fabrication process.

A phased array antenna is mainly designed with numbers of radiating elements each with a phase shifter. Radiation Beams are formed by shifting the phase of the signals emitted from all radiating elements to provide constructive or destructive interference so as to steer the beams in the desired direction. The antenna is the basic element in the field of wireless communication and finds its uses in various applications. For the satellite communications, at the microwave frequencies of the C band perform better under adverse weather conditions in comparison with Ku band (11.2 GHz to 14.5 GHz) microwave frequencies. The adverse weather conditions, can be referred to as rain fade, all have to do with moisture in the air, including rain and snow. This dual frequency Microsrip antenna array is designed on IE3D and Phase shifter is designed with HFSS software's. The phase shifter designed using UWB power divider with branch line coupler. This research provides a detailed insight of design and fabrication process of a phased array antenna with hybrid phase shifter using HFSS software and study the effect of phase shifter and antenna dimensions on the Radiation parameters of Bandwidth and return loss which are very effective parameters for design of antennas.

A space-fed X-band phased array antenna (PAA) is presented. The space-fed PAA uses physically autonomous individually addressable unit cells as the building blocks of an arbitrarily large array antenna. The X-band PAA unit cell consists of both a feed facing printed antenna element and a target facing printed antenna element. These elements are related by an RF phase shifter placed in the RF signal path between them which introduces relative phase delay and enables analog beam forming. Unit cell autonomy is realized by wirelessly transferring power and command signals required to operate a microcontroller (MCU) and the RF phase shifter at each unit cell. Each unit cell includes RF to DC conversion circuitry as well as an MCU designed to interpret a common control signal and command unit cell phase delay. The wireless phased array unit cell can be replicated in configurations of size and shape that are independent of RF, power, and array module control distribution networks. To demonstrate feasibility a four-element wireless PAA is constructed and antenna patterns for various control states are shown.

Novel acousto-optic systems for spectrum analysis and phased array radar signal processing are proposed. The pulsed source 2-D multiplicative time and space integrating spectrum analyzer is proposed and experimentally demonstrated. This architecture is simpler, physically smaller, and less sensitive to mechanical vibrations than the pulsed source 2-D additive Mach-Zehnder interferometer based spectrum analyzer. Simple and compact optical disk based systems for 1-D and 2-D spectrum analysis are presented. The high data packing density, angular motion, and parallel read out capability of optical disks is uniquely exploited to generate the very high time bandwidth product reference signals required for temporal spectrum analysis, that are otherwise difficult to generate using electronics. A continuous wave 1-D time integrating disk spectrum analyzer is successfully demonstrated in the laboratory. The limited dynamic range due to huge bias levels in interferometric time integrating processors is alleviated by using photorefractive crystals as real time bias removers. Continuous wave 1-D and 2-D bias free acousto-optic architectures for spectrum analysis are theoretically and experimentally investigated from a systems viewpoint. Simple, compact, and powerful acousto-optic systems for control and signal processing in phased array radars are proposed that eliminate many system components like phase shifters, mixers, power dividers, and complex antenna feed networks, that are encountered in typical electronically controlled phased array radars. Via a single control parameter, namely frequency, the optical technique provides appropriately phased signals for transmission and reception in phased array antennas. The system is capable of continuous beam scanning, simultaneous multiple beam formation, and multi-target tracking, and can be integrated on a substrate to provide smaller and lighter phased array radars. Also, the system is resistant to electromagnetic interference (EMI), and signal phase shifts are independent of the radar carrier frequency employed. A 1-D linear phased array radar acousto-optic beam steerer is successfully demonstrated in the laboratory, and performance issues such as detector phase sampling error and phase linearity are highlighted. The linear array design is extended to planar and multiple linear arrays.

Currently, antenna arrays are widely used in modern radio engineering systems. Phased antenna arrays, which can change the scanning beam angle, have become particularly widespread. Vivaldi antennas, used in antenna systems, are among the most promising and offer significant advantages in terms of broadband characteristics, multi-band operation, and gain compared to other antennas. This work examines one of the key components of a phased antenna array—the power divider. The role of the power divider in an antenna system is crucial, as it allows the incoming signal power to be split into multiple output channels. The main objective of this work is to study the primary types of power dividers used in antenna systems, as well as to develop power dividers for phased antenna arrays.

Recent deployments of satellite constellations have taken an increased interest in Low Earth Orbit (LEO) owing to the advantages of lower path loss, lower latency in terms of the propagation delay and coverage of concentrated pockets of area. Due to the nature of these orbits, antennas on the ground station with the ability to scan over wide angles is necessitated. Phased array antennas are the ideal candidates in such a scenario owing to their low cost, low profile and wide-angle scanning performance. In this paper, a phased array antenna is designed and presented to operate around the n261 band of 5GNRFR2 and the 28 GHz Ka-band with an azimuthal beamscanning range of 50° on either side of the boresight. There is also a symmetric elevation scan around boresight of +/-25° attained without the use of phase shifters. The antenna element consists of a multilayer series aperture coupled antenna fed by a meander line. It offers good performance in terms of beamscanning cost as the phase shifter requirement is reduced, owing to the use of frequency scanning in elevation and phase scanning only in the azimuth, drastically reducing the cost. The phased array has a good total efficiency around 80%. The antenna has been designed and its performance validated by full wave simulations in the solver CST Studio Suite.

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This paper presents the design of an electronically scanning phased array antenna which is constituted using 130 RF MEMS capacitive switches conflated with a series of linearly placed micro strip rectangular inset feed patch antennas and a corporate feed network. The design and analysis is performed in Ansoft HFSS (version 13.0). As the urge of obtaining high radiation pattern, light weight, low cost and better performance over wide range of frequencies, the micro strip antennas is still in demand. A phased array antenna using high-Q metal-insulator-metal capacitors which are intended as loading elements in the phase shifter have been designed in this context. The simulated result sights the designed 4-bit DMTL phase shifter which provides nearly 22.5°/45°/90°/180° phase shifts for different combination of MEMS switches. The design is optimized for Ku band at 15 GHz and the return loss for the phased array antenna is annexed to be -27.41dB. A highly integrated structure has been designed on silicon substrate having an area of 3.1×1.9cm2 only.

A 94-GHz phased array antenna using a log-periodic antenna has been developed on a GaAs substrate. The developed phased array antenna comprises four log-periodic antennas, a phase shifter, and a Wilkinson power divider. This antenna was fabricated using the standard microwave monolithic integrated circuit (MMIC) process including an air bridge for unipolar circuit implementations on the same GaAs substrate. The total chip size of the fabricated phased array antenna is 4.8 mm × 4.5 mm. Measurement results showed that the fabricated phased array antenna had a very wide band performance from 80 GHz to 110 GHz with return loss characteristics better than -10 dB. In the center frequency of 94 GHz, the fabricated phased array antenna showed a return loss of -16 dB and a gain of 4.43 dBi. The developed antenna is expected to be widely applied in many applications at W-band frequency.

ABSTRACTIn this study, we perform a low‐power wireless power transfer experiment to efficiently transfer energy using a phased array antenna (PAA). At the transmitting end, we used a 4 × 4 PAA consisting of left‐handed transmission line‐based compact phase shifters and inset‐feed microstrip patch antennas. The PAA used has a −30° to 30° tilting beam range with a gain ranging from 6.42 to 7.09 dBi. At the receiving end, we used an 8.9‐dBi single Yagi‐Uda rectenna at a distance of 0.8 m from the PAA and measured the converted DC powers to be between 1.5–2.2 mW for the tilting beam range. In the experiment, we limited the effective isotropically radiated power to 3 W because of concerns regarding human body safety. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:421–424, 2015

A low side lobe level pattern in a phased array antenna is desired for the radar systems. Time-modulated array has been investigated to achieve ultra-low side lobe pattern. We have proposed a time-modulated array using only phase control. In this method, a desired pattern can be achieved in a time average procedure by temporally controlling of each element phase. However, performance degradation of a phased array causes by amplitude and phase errors each antenna element under real environment. Therefore, amplitude-phase error compensation is important to realize the desired radiation pattern in phased arrays. In this paper, a novel time-modulated array using phase shifter is investigated for amplitude-phase error compensation. The effectiveness of the proposed method is demonstrated by computer simulation.