Active Phased Array Radar Research Articles

Design and Simulation Analysis of Antenna Structure for Active Phased Array Radar

Abstract This article adopts a modular design concept to design an active phased array radar antenna system structure and elaborates on its structural layout design and thermal design content. A finite element model of the antenna structure framework was established, and the rationality of its structural and thermal design was verified through static and thermal simulation analysis.

Thermal Design of Tile Type Active Phased Array Radar Antenna

Abstract Based on the structure and heat source distribution characteristics of the tile-type active phased array radar antenna, forced air cooling is adopted for its heat dissipation design. The heat dissipation path and fins of the main heating module of the antenna were designed and calculated, and the reliability of the thermal design was verified through software simulation and thermal testing.

Low sidelobe pattern synthesis for airborne distributed coherent active phased array radar

Low sidelobe pattern synthesis for airborne distributed coherent active phased array radar

Comparison of Low Pulse-Repetitive-Frequency Pulsed Power Supplies With Extremely Small Storage Capacitor

In active phased array radar, the T/R modules are powered by a low-voltage pulsed power supply (PPS). When the pulse repetitive frequency (PRF) is quite low, bulky storage capacitor or input <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> filter is often used in the PPS, resulting in a low power density. The two-stage PPS and the active capacitor converter (ACC) based PPS can greatly reduce the storage capacitor by intentionally increasing its voltage ripple. In this paper, the two kinds of PPSs with extremely small storage capacitor are compared in terms of the configuration, operating principle, main components and efficiency, and it is shown that the ACC- based PPS is more superior for low PRF than the two-stage PPS.

Angular Super-Resolution of Multi-Channel APAR in Interference Environments

Aiming to resolve azimuth-dense targets in interference environments, the radar needs to have the ability of single snap echo angular super-resolution with anti-interference. To solve the problem, the angular super-resolution algorithm based on single snap echo while anti-interference with blocking matrix method is studied for active phased array radar (APAR) in this paper. Since the super-resolution ability of the conventional MUSIC algorithm and iterative adaptive algorithm (IAA) algorithm are limited in single snap echo, the iterative re-weighted least squares (IRLS) algorithm under p-norm constraint is proposed. Further, the near main lobe interference suppression ability is enhanced by the adaptive diagonal loading method. The performance differences of IAA and IRLS algorithms for single-target detection and double-target angular super-resolution are analyzed in detail by numerical simulation on three scenes of no interference, side-lobe interference, and near-main-lobe interference. The simulation results show that the proposed algorithm can effectively solve the problem of target angle estimation and super-resolution based on single sample echo in an interference environment, including near main-lobe interference.

Investigation of active phased arrays performance deficiency due to array planarity and misalignment

ABSTRACT This paper investigates the degradation in the electromagnetic performance of an active phased array antenna and establishes the coupling relationship between the antenna array alignment/planarity to the near-field scanner probe. An analytical framework is presented to evaluate the sensitivity of radiation parameters of active phased arrays antenna due to the deviation of complex excitation vector. A laser-based positioning metrology equipment measures the near-field scanner plane to the antenna under test (AUT) plane in a global coordinate system. The antenna array surface is adjusted and aligned to the near-field scanner probe measurement plane within 1 mm (in S-band) by employing the mechanical mechanism within the positioning accuracies of 50–100 µ. The collimation of a perfectly aligned antenna array results in the alignment of electrical and mechanical boresight of the active phased array radar. The theoretical evidence and experimental results presented powerful tools and guidelines to set a reasonable tolerance for array alignment in the near-field test range (NFTR) to achieve high performances of the active phased array antenna.

Tailorable Switching of Transmission Modes between Waveguide and Spoof Surface Plasmon Polariton for Flexible and Dynamic Control of Phase Shift.

Programmable metamaterials are suitable for their dynamic and real-time control capabilities of electromagnetic (EM) functions in radars and antenna communications, but it remains a challenge to achieve dynamic modulation of arbitrary transmission phase with high transmission efficiency. Here, we propose a paradigm to tailor transmission phase shift in real time by switching modes between waveguide and SSPP based on the voltage-driven PIN diodes. Step-like phase shift is achieved by the "ON" and "OFF" states of PIN diodes, while continuous phase regulation is by the characteristic of the nonlinear region between those two states. As validations, three systems with programmable functionalities are implemented, including the multibeam generator, the dual-beam scanner, and the active phased-array antenna. The experimental results are consistent with simulation, which verify the feasibility of the proposed approach. Our work offers an alternative route for transmission full-phase modulation and provides unprecedented potential for high-gain, real-time, and multidimensional EM capabilities in applications such as active phased array radars, self-adaption radomes, smart beam shaping.

An active phased array radar in China

An active phased array radar in China

Design of TR module aging control system based on adaptive filtering algorithm

As an important part of active phased array radar, the working stability of TR module has a direct impact on the detection performance of radar system. This paper designs a set of TR electrical aging test system, for batch component aging test at the same time. Based on the principle of spontaneous heating under full power operation, the test environment was designed. The design of wave control board circuit met the excitation requirements in the work of the components. Meanwhile, the adaptive filtering algorithm and classical control theory were combined to control the TR working temperature, which realized the requirements of stable aging test of batch TR module. This system can accurately monitor whether the TR component products fail in the process of electrical aging, and at the same time can more accurately control the working temperature of the tested products within the required temperature range. It also provides a technical basis for further analysis and improvement of TR component product performance parameters. This design method can also be applied to the aging screening of other electronic board cards or components with high reliability requirements.

Advanced Photonics-Based Radar Signal Generation Technology for Practical Radar Application

Photonics-based radar technologies can implement better performance in some main functionalities of the radar systems. The outstanding question is whether these technologies are suitable for the practical application of modern or future radars. Here, we comprehensively analyze key radar parameters and summarize the requirements for the practical applications. Then, we present the corresponding photonics-based technologies capable of meeting actual radar needs. From the aspect of radar signal requirements, we compare the typical microwave photonic technologies for the radar signal generation at this stage and guide the improvement direction. The paper reviews the photonics-based radar signal generation based on a phase-locked dual-comb in detail. Further, the innovative and scalable capabilities of the scheme are presented, including the multi-band radar signal generation for multiple functions radar, and high accuracy beamforming for advanced active phased array radar. The enhanced performances include more flexible carrier frequency, large modulation bandwidth, tunable pulse duration, configurable pulse repetition frequency, full coherence, and continuous phase shift with ultra-high accuracy. The proposed novel photonics-based technology will greatly push forward the application of microwave photonics technologies in actual radar systems.

Extended block replacement policies with mission durations and maintenance triggering approaches

When the missions arrive, it is not feasible to shut down engineering systems for preventive maintenance policies. Otherwise, it would cause major economic losses and even unimaginable accident. Hence, it is interesting and significative to provide appropriate preventive maintenance policies with mission durations to improve the system reliability and maintainability. For the electronic systems consisting of a block or group of units whose ages are not easy observed and only failures are known, we firstly extend the block replacement policy with random arrival time of mission durations. As a required reliability is needed at the mission time and no replacement can be done during the mission durations preventively. From the points of cost and maintainability, two maintenance triggering approaches, i.e., replacement first and replacement last, are discussed in analytical ways, respectively. Furthermore, three replacement policies are compared theoretically and numerically with optimum mission durations and planned replacement time. In addition, a case illustration in maintaining the electronic systems of active phased array radar (APAR) is given when the arrival time of mission durations follows an exponential distribution and the failure time of electronic systems has a gamma distribution.

Real Time Design and Implementation of FPGA Based Timing and Control System for Wireless Radar Communication

This paper introduces real time application of FPGA based Timing Control Signal Generation card for Active Phased Array Radar Transmit Receive modules wireless radar communication. Active phased array radars usually have Transmit-Receive (TR) modules located near to the antenna elements and all the TR modules are to be synchronized for proper operation of the radar system. The TCSG is the heart of radar system which is designed to provide interface for digital controls, analog parameter monitoring, and timing and control signals generation required for 1 kW TR Module operation. The main objective of TCSG is to control and monitor the field located TR modules remotely from the control and instrumentation room, usually far away from the antenna field. Each TCSG card is provided with unique IP address and port number to distinguish each card though they perform same kind of operations. After remote connection establishment, the TCSG card responds to the commands given for controlling or monitoring the TR module parameters. A PC based user interface allows sending controls and monitoring the health of the TR modules. The functionality of the TCSG card is verified with a test bench setup and the results shows that the TCSG card is working properly for all the user parameters. The proposed framework comprises of detailed design, architecture, visualization, implementation and integration on a 1 kW high power TR module for the radar communication. Simulation of various control pulses for radar real time operations are carried out using Vivado and updated to the real time application using Artix-7 FPGA.

一种有源相控阵雷达TR组件电源系统

一种有源相控阵雷达TR组件电源系统

Novel Spray Cooling Plate for Thermal Control of Active Phased Array Radar

Based on spray cooling technology, a new high-integrated subarray cooling plate with multi-nozzles is presented for thermal control of active phased array radar (APAR) with high heat flux density. Firstly, by building a three-dimensional heat transfer and flow model, the simulation work was performed to evaluate both thermal control performance of presented cooling plate for APAR. Then, a special experimental thermal control system for the new cooling plate was established to investigate the thermal performance of presented cooling plate under both static state and vibrative state are investigated. The results showed that the nozzles in the cooling plate got high uniformity in pray characteristics. And by using the new cooling plate, the temperature rise of heat source could be controlled below 43°C with heat flux density of 323.3 W/cm2. Also, the temperature rise of heat source under vibrant state was lower than the static state.

Design and development of the optical control network active phased array radar

Active phased array radars for the atmospheric research have various advantages such as full beam agility in 360°, improved signal-to-noise ratio and improved sensitivity. These radars have distributed transmit–receive modules feeding to the individual antenna system in the antenna array field. In order to control and monitor the field-located transmit–receive modules from centralized radar controller which will be located few hundred meters away from the field, control signals plays an important role in controlling the radar subsystems. Earlier generation radars used electrical cables to transfer such type of signals, where signal speed and bandwidth are limited. In addition, the electromagnetic interference also affects the transmit and receiving signals. To overcome these problems, a new technical approach has been developed over optical interface for active phased array radar. In this paper, we present the design and development of the optical control signal network for 53 MHz active phased array radar. The design details, component selection and the link budget calculations are explained in detail and the test results are provided.

Dwell Time Optimization of Alert-Confirm Detection for Active Phased Array Radars

Dwell Time Optimization of Alert-Confirm Detection for Active Phased Array Radars

An Active Phased Array Radar Transmitter Design

This paper presents an active phased array radar transmitter design using Injection-locking oscillators. The required phase relation for each array element is obtained by electronic tuning through injection-locking technique, and the beam-scanning capability is demonstrated, so a shifter less beam scanning method is proposed.

Optimisation of radar search patterns in localised clutter and terrain masking under direction‐specific scan update rates constraints

Cognitive radars are systems capable of optimising emission and processing by exploiting knowledge about environment and operational scenario. Those improvements are achieved by controlling new degrees of freedom offered by modern radar technology. In particular, active phased-array radars can perform two-dimensional beam-steering and beam-forming. Those new capabilities allow adaptation of radar search patterns to localised constraints. The authors present an improvement from their previous set cover approximation for radar search pattern time-budget minimisation, accounting for localised constraints of terrain masking and direction-specific scan update rates. The addition of those constraints, however, does not modify the underlying mathematical structure of the problem, which can be solved using integer programming methods.

Evolutionary trends in Transmit/Receive Module for Active Phased Array Radars

&lt;p&gt;Worldwide, defense technologies are rapidly evolving and are currently aiming at integrating diverse functionalities like Radar, Electronic Warfare, Communications, etc., on a singular miniaturized platform. Hence, it cannot be denied that the advancements in modern Active Phased Array Radar technologies assume a critical role towards the achievement of this goal. A typical Active Phased Array Radar comprises of an Active Antenna Array Unit (AAAU) consisting of a large number of radiating elements, Transmit/Receive (T/R) Modules with other associated RF and digital circuitry and power electronics. This paper presents mainly the developments in Transmit/Receive (T/R) Module technology, which assimilates various stages of the technological evolution - past, current and futuristic. It discusses how these technologies contribute towards the improvement of efficiency, miniaturization and reliability without compromising its performance parameters.&lt;/p&gt;

Development of the algorithm of reliability­centered maintenance of phased array antennas

The strategy and algorithm of reliability-centered maintenance of active phased array antennas are developed. The use of this strategy and algorithm makes it possible to determine the time and volumes of corrective replacements of the antenna subarray modules based on the results of predicting the reliability indexes of the array antenna as a whole. This procedure is performed as a result of consistent refinement of statistical estimates of reliability indexes of the modules during the normal operation of the phased array antenna. For processing statistical information on the failures of the array antenna modules and determining the estimates of the sample mean, upper and lower confidence limits, the method of quantiles is used. As the law of distribution of the operating time of the array antenna modules, the combination of exponential and diffusion nonmonotonic distributions is used. The example of implementation of the reliability-centered maintenance strategy and algorithm for the receive phased array antenna including 100 antenna subarrays is presented. The results of the research can allow organizing the APAR condition-based maintenance and minimizing the operating costs. Implementation of the obtained results can ensure failure-free operation of active phased array radars during operation with the timely provision of antenna subarrays with spare modules.