Simulation and experimental measurement of digital multi-beamforming phased antenna array in the frequency range C

The choice of element for constructing a phased antenna array (PAA) providing a relative frequency bandwidth up to 9% for the transmission or reception of wireless communication system information was carried out. There are three methods to suppress of side lobes and diffraction of PAA in the radiation far field. Superposition of excitation signals of a flat PAA for simultaneous emission of several independent beams in a radiation far field was used. Сalculation and optimization of progressive distribution of phase shifts in the excitation signal group in the horizontal and vertical directions in the plane of PAA for radiation (reception) of independent beams in spherical coordinates (azimuth and elevation) in space was performed. An experimental sample of a phased antenna array was developed using microstrip technology, which forms several beams in a radiation far field. An experimental measurement of the voltage standing wave ratio and relative frequency bandwidth of the sample developed by phased array microstrip and printing technology was carried out.

The process of designing of digital active phased antenna array (PAA) is described. Antenna elements can operate in wide frequency band. The comparison of experimental or calculated results is presented. The recommendations on PAA modernization and characteristics improvement are presented.

A new method which is to solve the problem of the digital active phased array antenna fast measurement method based on correlation technique is presented. In this method, a test probe is fixed in the mid-field of phased array antenna, for receiving orthogonal excitation signals sent by the elements; and the initial channel excitation can be fast restored by correlation detection; then with the active element patterns, the radiation characteristics of the array under test can be obtained. Finally, the simulation results of a digital active phased array antenna model are demonstrated here to illustrate the feasibility and accuracy of the proposed method.

On the basis of the analysis of the errors of the monopulse method of direction finding of the target of a radar station with a digital antenna array, a group of errors associated with fluctuations of the equisignal direction when scanning the beam of the antenna system, as well as with the non-identical shape of the generated beams of the monopulse group, was separated into a special cluster. This circumstance is especially critical for large-aperture radars with phased array with electric scanning, where the number of formed receiving beams is significant, in addition, the coordinates of the target usually do not coincide with the coordinate planes along which the coordinates are measured. The nonlinearity of this problem requires unique approaches and solutions. The classical formulation of the problem is associated with obtaining an estimate of the radiation vector of the entire antenna array from the known measured vector of complex signals at the output of the antenna array at a fixed time. To solve this problem and determine the decision rule, a neural network approach was used, while the neural network was trained according to the criterion of the minimum of the selected objective function. The substantiation of increasing the accuracy of measurements of angular coordinates in monopulse systems with scanning digital phased antenna arrays based on the use of neural networks in the process of radar data processing without the formation of direction finding characteristics is given. The results of modeling the characteristics of the antenna array (using the example of a flat antenna array with a dimension of 30 by 30 emitters) under the conditions adopted in the model of the antenna array of assumptions when implementing the classical and original methods are shown using examples of the surfaces of the variances of errors in measuring angular coordinates by the monopulse method in a rectangular spatial domain, which showed reduction of error and expansion of the measurement area. In the future, the practical implementation of this approach is assumed using FPGA in the receiving paths of the frequency-dependent part of the radio direction finder.

Micro-Nano and intelligent satellite products are the future development direction. As an important part of satellite products, the digital phased array antenna has established the satellite-ground data receiving and receiving channel, and the research of micro phased array antenna has become the key to design the control system of micro digital phased array antenna. In this paper, the digital phased array antenna control system is designed based on the core of DW8051 single chip microcomputer embedded in SRAM FPGA. At the same time, the anti-fuse FPGA is used for read-refresh design to correct the single particle flip error of SRAM FPGA. The timing control of T component, logic control of antenna array, remote control of power supply and other functions are completed, and the design of micro-digital phased array day control system is realized.

Modern radar systems often have the conflicting requirements of a large phased array antenna for increased power-aperture product and/or angular resolution versus wide instantaneous signal bandwidth for fine range resolution. Pulse-to-pulse diversity may also be desired as a countermeasure against coherent repeater jammers. Using the multicarrier nature of orthogonal frequency-division multiplexing to encode wide instantaneous bandwidth pulses we propose a novel digital phased array architecture which mitigates dispersion effects experienced when the array main beam is electronically steered off broadside. The result is the ability to transmit and receive wideband pseudo-random phase coded pulses with a phased array antenna. Simulation results are used to quantify the benefit of the architecture. An overview of digital orthogonal frequency-division multiplexing waveform generation is also provided.

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.

This paper describes the design and implementation of an X-band scalable $4\times 4$ element-level digital phased array module. The module consists of sixteen active antenna elements. Each of these elements includes one custom CMOS RF SoC and one custom GaAs switch frontend IC. The RF SoC is implemented using a 65-nm CMOS process. The T/R Switch frontend IC is implemented in a $0.15-\mu \mathrm{m}$ GaAs pHEMT process. The module also includes a digital signal processor implemented in an FPGA SoC device, and the required power supply subsystems. This module can be used to build a large hierarchical digital phased array through synchronizing four LO signals at system level. The built array serves as a tool for researching software-defined phased array radar and communication systems. This paper reports initial test results of this module. This module achieves a state-of-the-art 42-mm scalable tile thickness.

In spite of the major recent advances in the phased array radar and communication systems, calibration in general is still a major challenge. In this work, a quasi-near-field fixed probe based calibration framework is proposed, which is capable of ‘One-Shot’ calibration without any system downtime for digital phased array. Both theory and mathematical model has been developed for different error sources. The error evaluation relative to ‘ground-truth’ has been demonstrated for calibration purpose.

Summary form only given, as follows. A millimeter wave phased antenna array (PAA) has been proposed for use in plasma imaging reflectometric diagnostics and is currently under design and fabrication. To account for the rapid changes of the cutoff layer with plasma density variation, a true time delay (TTD) controlled phased antenna array (PAA) is being developed as an artificial lens with controllable focal length for launching the illumination beam of the microwave imaging reflectometry (MIR) system. The beam shaping concept illustrates that programming the PAA generates concave (focusing/beam narrow) or convex (defocusing/beam broaden) wavefronts by properly arranging the time delay (or phase shift), therefore, the PAA functions like a real optical lens. The focal properties can be easily changed by different time delay arrangement at high speed so that real time control is possible on time scales significantly faster than plasma changes. The operation frequencies for the first implementation of beam shaping antenna array are set as 45-55 GHz based on the NSTX MIR system requirements. The time delay unit utilizes a piezoelectric translator (PET)-driven perturber to vary the propagation velocity along low loss microstrip lines. Tapered slot antenna will be used in the system as array element. To overcome the system loss and scattering loss from the plasma, the beam shaping array system is designed with an output power of at least 50 mW, and with a desired variable 3-dB beam width extending from 15/spl deg/ to 25/spl deg/.

Various smart antennas developed for automatic radio frequency identification (RFID) readers are presented. The main smart antennas types of RFID readers are switched beam, phased array, adaptive beamfsorming and multiple input multiple output (MIMO) antennas. New development in the millimeter wave frequency band?60 GHz and above? exploits micro-electromechanical system (MEMS) devices and nano-components. Realizing the important of RFID applications in the 900 MHz frequency band, a 3×2-element planar phased array antenna has been designed in a compact package at Monash University. The antenna covers 860-960 GHz frequency band with more than 10 dB input return loss, 12 dBi broadside gain and up to 40° elevation beam scanning with a 4-bit reflection type phase shifter array. Once implemented in the mass market, RFID smart antennas will contribute tremendously in the areas of RFID tag reading rates, collision mitigation, location finding of items and capacity improvement of the RFID system.

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

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.

Formulation of the problem. Many electronic applications (for example, satellite communications) impose significant restrictions on the weight and dimensions of the antenna devices used. In addition, the antennas used should have the lowest possible cost and simplicity of design. To solve these problems, it is proposed to use a method for reducing the number of antenna elements in phased antenna arrays based on the method of point sources. Purpose. The purpose of this work is to develop a method for reducing the number of antenna elements in phased antenna arrays while maintaining the parameters of their radiation patterns. Results. As a solution, it is proposed to place the antenna elements above the metal sheet at a distance 1.5–2 times smaller than the size of the antenna array itself, which will significantly reduce the number of elements of the latter without deteriorating its radiation pattern during wide-angle two-coordinate scanning of space with the main lobe. Practical significance. Obtained results can be used to create phased antenna arrays with a reduced number of elements, which will reduce the size, weight and cost of the device.

Phased antenna arrays patterned on optical waveguides can strongly affect mode coupling and propagation in the waveguides. The unidirectional effective wavevector provided by the phased antenna array can facilitate phase matching between different waveguide modes; the effective wavevector can also breaks the symmetry of optical power flow in waveguides. These effects can be used to realize novel integrated photonic circuits. We used full-wave simulations to demonstrate broadband, small-footprint optical waveguide mode converters, polarization converters, and optical power diodes in the telecom and mid-infrared spectral ranges. The designed optical devices have small footprints (i.e., length of antenna arrays ranges from a few to ten times of the free-space wavelength). The efficiency of mode conversion (defined as the percentage of optical power coupled from one waveguide mode to the other) ranges from 10% to 60%, and the purity of converted modes approaches unity. The on-off ratio of optical power diodes (defined as the ratio between optical power transmission in two opposite directions) can be larger than 20dB over a broad wavelength range. We developed a coupled mode theory to model the asymmetric coupling between different waveguide modes and between waveguide modes and surface waves propagating along antenna arrays. The results calculated using the coupled mode theory can successfully explain mode evolution in our waveguide structures observed in simulations. We believe the platform of optical waveguides integrated with phased antenna arrays offers great opportunity to study novel physics originating from interaction between guided waves and designer structures. The platform also has great implication for integrated photonics device applications.