幅相误差对有源相控阵天线副瓣的影响

对误差分布函数进行了理论分析,通过分析有源相控阵系统的组成,构建了其误差组成结构,并推导了误差计算公式.通过理论推导和仿真分析研究了幅相误差对有源相控阵天线副瓣电平的影响.结合误差计算公式和副瓣电平公式得到了实现所需副瓣电平的幅相误差分配方法.     

相控阵天线及其功率合成方法分析

相控阵天线是当前干扰设备研究领域的重要设备之一。在介绍相控阵天线特点及构成的基础上,重点分析了通道的相位不一致性、天线的驻波导致的反射损耗、阵列单元间的互耦、天线阵的合成效率等诸因素对相控阵功率合成效率的影响,并就达到一定的干扰功率进行了初步设计。     

Phased arrays in radar

Modern microwave phased arrays with electronic beam-steering allow surveillance and tracking with variable data rates in a multifunction radar. The author reviews system options and discusses the engineering of active arrays, using as an example, the Siemens Plessey Radar/ARE MESAR, which is now undergoing trials and which is the first modular active array radar in the UK. Future applications, the success of which depends on cost-effective production of active transmit-receive modules, improved beam control, and larger wideband arrays, are outlined     

Difference pattern synthesis in small planar phased arrays

A pattern synthesis technique for low sidelobe arbitrarily scanned difference beams in small planar phased arrays is presented. The approach is based on adaptive array theory and is the development of a technique used for radiation pattern synthesis in linear arrays. The method has been applied to measured element pattern data from a small planar array, which includes the effects of pattern corruption by mutual coupling. The successful synthesis of low sidelobe difference beams is demonstrated, with arbitrary difference plane and scan angle     

Beam Steering with Linear Arrays

The principles and techniques of real-time imaging with phased array ultrasound scanners are reviewed. Topics include 1) the geometric optics of beam steering and focusing with a linear array in the transmit and receive modes; 2) limitations on image data acquisition due to ultrasound propagation velocity; 3) optical diffraction theory for linear arrays including effects of amplitude grating lobes. Limitations on the image quality of phased array imaging systems are also discussed, including 1) nonideal response of array transducers; 2) target ambiguities caused by phase error grating lobes; 3) refraction errors; 4) delay line design. Finally, an analysis is presented of current techniques for improving ultrasound image quality using phased array methods including phase compensation, spatial compounding, frequency compounding, and parallel processing.     

On-board non-linear circuitry for Ku-band active arrays

Active phased arrays will play an important role in future satellite communications, because of the system flexibility and potential reconfigurability that they may provide. Therefore, an investigation of the relationship existing between payload characteristics and the synthesis parameters of this kind of antenna may constitute a helpful tool. To this end, a parametric analysis of the on-board non-linear circuitry of the transmitting system (power and up-converter sections) has been carried out, establishing the dependence of the mass and DC power demand on the number of beams and feeds of the transmitting phased array. The parametric investigation has been, in particular, applied to an active imaging phased array and an active direct radiating phased array whose suitability to provide a multibeam coverage of Western Europe at K_u band has been demonstrated within an ESA/ESTEC contract. This paper describes the parametric approach followed in the investigation of the on-board non-linear subsystems of the active transmitting phased arrays. The assumed circuitry configurations are widely commented, and the parametric curves for the case of imaging and direct radiating phased arrays are reported.     

Pattern synthesis based on adaptive array theory

Pattern synthesis based on either optimization of signal-to-noise ratio or noise minimization is developed. The connection between adaptive arrays and adapted pattern shape is used in synthesizing linear array patterns with freedom to adjust both amplitude and phase. Phase-only pattern synthesis is described in connection with suppressing interference or clutter in proportions of space. A planar array example applied to a constant-amplitude solid-state phased array is discussed     

射频MEMS及其在相控阵系统中的应用

概述了国内外射频MEMS移相器的研究情况,分析了射频MEMS技术给相控阵系统设计带来的优 势如：降低系统功耗,实现宽带阵列、自适应阵列与低成本相控阵等,介绍了国外MEMS相控 阵天线实例与毫米波MEMS相控阵系统方案。     

Computer simulation of synthesizing images by digital phased arrays

A method of synthesizing images by digital phased arrays is proposed. Following this method a numerical experiment of image synthesis is conducted to simulate arrays of 64 × 64 by computer. Each array element is assigned a binary digit, that is, it is either excited or nonexcited.     

Extending the Field of View With Phased Array Techniques: Results of European SKA Research

The radio frequency window of the square kilometre array is planned to cover the wavelength regime from centimeters up to a few meters. For this range to be optimally covered, different antenna concepts are considered. At the lowest frequency range, up to a few gigahertz, it is expected that multibeam techniques will be used, increasing the effective field-of-view to a level that allows very efficient detailed and sensitive exploration of the complete sky. Although sparse narrow-band phased arrays are as old as radio astronomy, multioctave sparse and dense arrays now considered for the SKA require new low-noise design, signal processing, and calibration techniques. The successful implementation of these new array techniques has already been introduced for the use of phased array feeds upgrading existing telescopes: enhancing aperture efficiency as well as effective field-of-view. Especially the development of low-cost array antenna design will allow a cost-effective large-scale implementation for the SKA. This paper addresses these new capabilities, emphasizing the R&D work done in Europe and aims to provide insight into the status of enabling technologies and technical research on polarization, calibration, and side-lobe control that will unleash the potential of phased arrays for future growth of radio astronomy synthesis arrays.     

On the removal of blindness in phased antenna arrays by element positioning errors

The effects of random errors in positioning the elements of uniform phased arrays on the scanning pattern are investigated. Expressions for the mean and variance of the element pattern and the complete array pattern are given and a typical computer-simulated array is also studied. The curves show that the sharp dips which occur at some scan angles in the case of the hypothetical error-free array are filled in, and the blindness is completely removed for large values of the error parametersigma. A simple feeding system is presented to partially correct the element phasing for the element positioning errors.     

阵元幅相误差对AEW雷达二维杂波谱的影响

本文研究了不可避免的阵元幅相误差对各列先微波合成为列子的矩形侧面相控机载预警（ＡＥＷ）雷达二维杂波谱的影响，并分析了基于理想“脊背型”杂波谱的二维信号处理性能下降的原因，为深入研究时空二维处理提供了基础。     

Analysis of finite phase arrays of microstrip patches

A method for the analysis of large phased arrays of microstrip patches is presented. It is based on an infinite array approach where the edge effects are taken into account through the convolution with a proper window function. In the first step, a rigorous Green's function corresponding to a finite array of elementary sources is derived. This Green's function is then used to analyze the finite phased array of microstrip patches. Results are shown for the active impedance and element patterns of several arrays, and compared with measurements or, in the case of small arrays, with results obtained by a rigorous element-by-element approach. It is shown that the method, even if developed for the analysis of large arrays, is able to handle small arrays. Indeed, the results obtained are good even for single patches. Although the method has been developed for the microstrip phased array case, the results are general and are valid for any phased array with a rectangular grid     

Pattern synthesis in small phased arrays using adaptive arraytheory

A pattern synthesis technique for low sidelobe difference and scanned beams in small phased arrays is presented. The approach is based on adaptive array theory and is a development of a technique used for beam synthesis in an ideal, λ/2 spaced, isotropic array. The method has been applied to measured element pattern data from a five element linear array, which includes the effects of pattern corruption by mutual coupling. The successful synthesis of low sidelobe sum and difference beams are demonstrated, with the look direction on and scanned off boresight     

A Modular and Lightweight Multibeam Active Phased Receiving Array for Satellite Applications: Design and Ground Testing

A 17 GHz receiving multibeam active phased array, based on modular “suopertiles,” was built and tested. The array was launched and placed in geostationary orbit in 2008. The tile concept is characterized by low volume and low mass, making it well suited for satellite-antenna applications, and in particular for deployed multibeam active phased arrays for communications satellites. The modular design facilitates low recurring cost in a high-volume continuous production. Both component and array measurement data are presented in the paper. Measured array-antenna patterns were in good agreement with estimated and predicted values, proving that the array can be built according to its requirements, and calibrated and controlled to generate independent beams with low sidelobes from low-rms excitation errors.     

基于K-means聚类的相控阵任意形状波束子阵综合方法

传统相控阵由于设计复杂性和成本过高,已经不能满足日益增长的应用需求,子阵划分等技术较好地解决了这个问题。本文提出一种任意形状波束相控阵子阵综合方法,在激励匹配策略下,将子阵综合问题转化为一个子阵布局优化问题,而子阵的复激励可解析地从参考阵列激励计算得到。利用一种无监督聚类K-means方法对子阵布局优化问题进行求解,该方法能同时对子阵的激励幅相进行优化,增加了子阵综合的自由度和灵活性。在任意形状波束子阵综合数值算例中,通过与传统智能优化方法在方向图逼近、激励匹配代价函数、阵列性能参数及计算效率等方面的比较,验证了所提方法的有效性。     

Spatial statistics of instrument-limited angular measurement errors in phased array radars

The major contributors to the random component of the instrument limited angular measurement errors in electronically scanned phased array radars are reviewed and formulas are developed for statistical modeling of these error sources. The error model employed is applicable to space-fed and certain types of corporate-fed arrays. A comprehensive computer program, embodying this analysis, has been developed for determining these array measurement errors and their spatial correlation statistics, in two angle variables. This program is used to evaluate the statistical behavior of angular errors for some typical situations of interest. The use of angle, frequency, and phase "dithering" for improving the correlation statistics of these arrays is examined. The phase dithering technique is shown to be at least as effective as angle and frequency dithering and has the virtue of being readily implemented in the beam steering computer.     

超低副瓣相控阵天线设计中的几个问题

本文论述了超低副瓣相控阵天线的设计方法，它涉及诸多因素，这里主要研究诸如阵列单元互耦，单元与馈电系统之间的传输变换段，阵列激励与位置误差，以及单元通道校准问题。     

阵列方向图综合的一些方法

介绍了几种常用的阵列方向图综合方法。切比雪夫阵列在指定的副瓣电平下主瓣宽度最窄,在指定的主瓣宽度下副瓣电平最低;相位控制技术通过控制阵列各单元的相位实现波束的指向变化;最后介绍了遗传算法并利用遗传算法优化了8元线阵,将其相对副瓣电平抑制到了-50dB。