Characterization of Ka-Band phased Array Systems: Modeling and Experimental Verification

By dividing the available spectrum into multiple bands, multi-band ultra-wideband (UWB) systems possess many advantages, such as the flexibility to eliminate possible interference and coexistence problems with available wireless standards. UWB channels have large delay spread, causing inter- symbol interference (ISI) in high rate systems. The RAKE receiver is often used to capture multipath energy, but it is incapable of ISI compensation, causing severe bit error rate (BER) degradation in practical UWB channels. This paper proposes an over-sampling multi-channel equalizer per sub-band for multi-band UWB. The performance of the proposed receiver is compared with the RAKE receiver through analytical and simulation studies. The proposed equalizer has been shown to be able to handle ISI under any channel conditions or data rate presented, with an acceptable BER. In addition, the rich multipath diversity of the UWB channels is harnessed by the over-sampling scheme, for output SNR improvement. one. Therefore, equalization receiver based on adaptive algorithms seems to be an effective way to recover the transmitted data. With this consideration, we propose an over-sampling multi-channel equalizer per sub-band for a multi-band UWB system, which provides more effective inter-symbol interference (ISI) suppression compared with the conventional RAKE receiver when operating in channels with large delay spread. Through detailed theoretical analysis and extensive simulations, we are able to show that the proposed 4-arm equalizer scheme is superior to a 4-arm conventional RAKE receiver in the presence of ISI at all signal-to-noise ratios (SNRs). Based on the method presented in (4), the simulated performance is shown to conform to analytical predictions. The RAKE receiver is incapable of ISI compensation, and a moderate level of ISI is shown to cause severe bit error rate (BER) degradation. The proposed over-sampling equalizer, on the other hand, is able to handle ISI under any channel conditions or data rate, with an acceptable BER. Over- sampling is shown to be able to achieve diversity gain, and improves the output SNR.

Beam-steering antennas are the ideal solution for a variety of system applications, it is most commonly achieved through using phased arrays, where phase shifters are used to control the relative of the main-beam. In this paper, a low-cost directive beam-steering phased array (DBS-PA) antenna using switched line phase shifters is demonstrated. The proposed DBS-PA antenna has four micro-strip patch antennas, three power dividers and four phase shifters printed on the same Rogers RT-Durroid substrate with a dielectric constant of 2.2 with dimensions of 8 × 3.5 cm. The phased array antenna has a directivity of 15 dBi and the main beam direction can be switched between the angles of ±30 degrees with a 3dB beam-width of 25 degrees. All design and simulations have been carried out using Agilent AdS and Ansoft HFSS software tools. The frequency considered for the operation is 10 GHz.

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.

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.

Phased array antennas are becoming more and more ubiquitous largely in part because of the provision within the 5G protocol for millimeter-wave beamforming. As silicon phased array beamforming core chips become widely available, this opens cost effective solutions for highly agile line of sight (LOS) communications links which utilize classical phased array antennas. This paper describes the development and demonstration of a 0.4 km RF link which operates in the Ku-Band (13.8 GHz), which supports up to 30 Mbps data rates. The developed system is demonstrated utilizing laboratory instruments as well as with a small form factor radio. The developed phased array antenna is able to maintain link at 0.4 km at scan angles up to ±60°, utilizing a digitally modulated signal (32-QAM) at a symbol rate of 5 Msym/s while maintaining an RMS EVM of less than 6%.

Design of a compact multilayer circularly polarized phased array transmit antenna system for satellite applications

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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.

The advantages of the new digital-analog principle of operation for phase shifters using ferroelectric (FE) film varactors are considered. The results of the theoretical investigation are confirmed by testing of a 1.8GHz device with a figure of merit F=120 deg/dB and a phase error < ±2° in bandwidth Δf/f ~ 5%. The response time of the phase shifter to control pulse corresponds to units of nanoseconds. On the base of analysis of properties of ferroelectric varactors the theoretical estimation of nonlinear behavior of digital-analog phase-shifter in two-tone input signal regime is executed. Expected parameters of a multilayer microstrip phased array antenna based on phase shifters with ferroelectric varactors are presented.

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&#x00B0; on either side of the boresight. There is also a symmetric elevation scan around boresight of +/-25&#x00B0; 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.

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.

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.

In phased array antennas, the high side-lobe levels due to the amplitude quantization often need to be reduced to meet some requirements. In order to develop the digitalization of antenna arrays in phased array radars, the amplitude quantization of aperture distribution in array antennas is studied. In this paper, the random technique and a novel appropriate random technique are presented and used to reduce the side-lobe levels, and the side-lobe levels in the amplitude quantized array pattern are calculated. The reduction of side-lobe level due to amplitude quantization are introduced using the improving method and confirmed with computations, where the related parameters are modified and numerous patterns are computed and compared. The quasi-optimum patterns are also obtained and given.