Ku、Ka频段龙伯透镜馈源阵列技术研究

针对卫星通信中龙伯透镜天线不同频段的馈源并排放置导致最大波束指向的偏移,无法实现多频段馈源上、下行跟踪同一颗卫星,提出了馈源阵列馈电的方法。通过辐射口面采用介质杆天线取代喇叭以改进馈源,此方法减小了馈源的阵间距,利于馈源组阵。结果表明:利用馈源组阵技术可以解决波束偏焦问题,实现多频段收发同一颗卫星的目的,同时也分析了阵列馈源馈电对天线增益和效率的影响。     

一种小型化双收、单发线极化馈源

介绍一种适用于抛物面天线馈电的小型双收、单发三端口线极化馈源,该馈源在收、发各15％的频带内具有近乎旋转对称的波束,系统驻波比小于1.2,极化隔离度优于40分贝,收发隔离度大于100分贝。其优点在于体积小、功能全、性能价格比高。     

有限扫描反射面天线相控波束重构技术

该文研究一种采用聚焦馈源阵列馈电的反射面天线,相控阵馈源离开焦平面向反射面移动一定距离,位于焦散区,能够增强反射面天线的波束重构赋形能力和有限视角扫描能力。采用改进的投影矩阵法,利用仅相位控制技术,求解相控阵馈源的激励系数,有效综合了聚焦馈源偏置抛物面天线的方向图。对算例的设计达到了采用仅相位技术控制波束指向、波束赋形、旁瓣电平等性能要求,实现了相控阵馈电偏置抛物面天线的波束重构或扫描,并利用商用GRASP仿真软件验证了该文的设计结果,说明了该文方法的有效性。     

一种快速稳健的致密焦面阵列馈源设计方法

致密焦面阵列馈源(DFPAF)融合了多喇叭多波束馈源和相控阵列馈源(PAF)的特点,与多喇叭多波束馈源和常规相控阵列馈源相比较,它可以同时提供更多的固定赋形波束进一步拓宽视场。在射电天文、雷达、电子侦察和卫星通信等领域引起了极大的关注。由于其阵列结构与常规阵列馈源不同,导致设计方法也具有特殊性,因此近年来展开了对其设计方法的研究。该文充分利用反射面天线的固有特性,并结合阵列天线理论,提出一种可以快速、稳健地设计致密焦面阵列馈源的方法,给出了设计原理和设计结果,并和最具代表性的多喇叭多波束馈源进行了性能对比分析,为设计致密焦面阵列馈电的大型反射面提供理论和数据参考。     

采用相控阵馈电反射器的多波束天线

本文对相控阵馈电单反射器天线作了分析研究，并阐明了馈源单元数量是最重要的设计参数，计算出的辐射特性证实了相控阵馈电单反射器天线适用于大型多波束天线。     

偏置天线设计与分析

多波束天线在卫星通信中主要用于星体上,由于偏焦的各个馈源形成各个单波束,可由馈电网络面电流组合起来,形成一个赋形波束覆盖整个照射区。必要时也可单独使用各个单波束,这样一副天线就有多种工作方式。实现多波束有两种途径,一是通过多波束合成网络来实现一个赋形波束或多个单波束;另一个方法是控制馈源与焦点(O′)的相     

宽频带双圆极化单脉冲馈源设计

介绍了一种宽频带双圆极化单脉冲馈源,采用了一种新型馈电方式的单极对数周期天线单元,并利用这种单极对数周期单元以等间距的方式序列馈电,均匀地将8个单极对数周期天线布在一个圆锥上,巧妙地解决了宽频带内的组阵问题。用宽频带双圆极化波束形成网络馈电的该馈源,已成功地应用于某旋转抛物面。实验结果表明,该馈源工作于C波段,具有良好的左/右旋双圆极化和差性能,满足了实际使用的要求,在电子战领域具有很高的应用价值。     

卫星通信有效载荷用的多波束双频段阶梯反射器天线

本文介绍了一种适用于双频段多波束卫星有效载荷的新型阶梯反射器天线（SAR）。这种SAR系统用于地球同步卫星，可向地球覆盖区产生“平顶”辐射方向图接收波束和高效率高斯方向图发射波束。它综合利用改进后的阶梯反射器天线和双频段高效率馈源喇叭实现高效率多波束天线（MBA），支持通信卫星信号的下行发射和上行接收。已表明SAR可发射接收一组重合点波束，并显著地改善了边缘覆盖增益，提高了复用相同频率信道的波束间同极化隔离度，接收波束对卫星指向误差的反应小，与传统多波束天线相比还减少了反射器数量。     

一种板线馈电背腔式振子馈源的设计

背腔式振子馈源体积小、结构简单、调节灵活、电气性能好等优点,并且采用板线的形式进行馈电后,可以实现良好的宽带匹配性能。这种馈源由辐射振子、反射腔及其馈电部分组成,馈电部分采用板线形式并且具有便于调节的短路片。实测结果表明,这种馈源具有较宽的匹配和方向图带宽。该馈源尤其适用于L波段或S波段等频率较低的频段,用作前馈反射面天线的馈源。     

多模双馈阵列雷达天线

一种多孔径阵列天线,通过梯形馈电结构的前馈源为照射波束提供波束宽度窄、旁瓣低的辐射方向图。另一方面,将梯形网络的后馈源作电锥削,从而取得三个同时低旁辦小孔径,用移相器对它们分别独立定向而取得的不同的接收波束,可用于干涉测量相位补偿。三个孔径各自范围内的每个辐射单元都连接有一个馈源,以产生用于旁瓣对消的宽波束方向图。每个辐射单元邻近处设置一个移相器,从而通过精确控制每个端口的相位激励实现天线功能的切换。馈电结构以梯形布局形式连接,这样就形成了前馈源与后馈源。前馈电网络通过一个馈电结构连到发射机,于是所有辐射单元都可用于产生一个高增益窄照射波束,作搜索和测绘之用。后馈电网络通过三个不同的馈电结构连到各自的接收机上,因而每个接收机可用三分之一的辐射单元来形成各自的低增益宽波束孔径,用于干扰测量方位方向。根据加到移相器上的适当信号,还可对经后馈电网络而形成的三个独立孔径分别定向。     

数字多波束形成系统的分析设计

数字波束形成技术在阵列信号处理中应用愈来愈广泛，采用数字波束形成技术实现多波束具有很高的灵活性。论文对数字式多波束形成系统进行了较详细的分析，对工程设计中波束宽度、影响波束合成效率的主要因素进行了仿真分析，对系统的幅相校准方法进行了讨论。文中给出设计完成后的系统硬件及说明。     

Hybrid wideband transceiver design for achievable rate maximization in millimeter-wave MIMO systems

Telecommunication Systems - This paper proposes two algorithms for hybrid (Analog–Digital) beamforming in a single-user millimeter-wave (mm-wave) multi-input multi-output (MIMO) systems under...     

数字波束形成器的FPGA实现

数字波束形成技术是天线波束形成原理与数字信号处理技术相结合的产物，其广泛应用于阵列信号处理领域，本文介绍了数字波束形成器的基本原理及其FPGA的实现结构。     

数字阵列雷达及其进展

数字阵列雷达是一种接收和发射波束都以数字方式实现的全数字相控阵雷达。由于数字处理所具有的灵活性,数字阵列雷达拥有许多传统相控阵雷达所无法比拟的优越性。本文对数字阵列雷达及其研究进展进行了评述,主要介绍数字阵列雷达的基本原理、关键技术、研究进展,并对数字阵列雷达的应用前景进行了分析,提出了数字阵列雷达发展应考虑的一些问题。     

Outage Probabilities of Wireless Systems with LCMV Beamforming

This paper investigates the outage probability of a wireless system with linear constrained minimum variance (LCMV) beamforming using a uniform linear array beamformer. LCMV beamforming is able to perfectly cancel a number of dominant interferers while other interferers remain. A simplified beamforming model is used to derive closed-form outage probability expressions considering the impact of LCMV beam patterns on various interferers. Fading statistics of Rayleigh, Rician, and Nakagami are used to characterize the desired signal, whereas interferers are assumed to be subject to Rayleigh fading. One important aspect of this paper is the consideration of the directions of arrivals (DOA) of the dominant interferers and the exact beam patterns in the outage performance evaluations of LCMV beamforming systems. Numerical results of the outage probability are presented to illustrate the impact of DOA's of the dominant interferers and the impact of different fading scenarios. The paper also presents performance comparison between LCMV beamforming and conventional beamforming considering different interference scenarios (DOA's of dominant interferers).     

G/T maximization of a paraboloidal reflector fed by a dipole-diskantenna with ring by using the multiple-reflection approach and themoment method

A 1.8-m paraboloidal reflector fed by a dipole-disk antenna with a beamforming ring is optimized for high G/T at L-band by using the moment method (MM) and the multiple reflection (MR) approach. The MR approach is based on using MM to calculate the radiation and scattering patterns of the feed, using physical optics plus uniform geometrical theory of diffraction (UTD) to include the reflector, and in addition to include the mutual interaction (multiple reflections) between the reflector and the feed by using the expression for the sum of an infinite geometric series. The MR approach is shown to be equally accurate as a MM solution of the complete antenna with reflector, provided the reflector is in the far field of the feed, and the MR approach is much faster. As a result of the calculations using the MR approach, design curves are presented showing how the G/T varies as a function of antenna geometry, size, and elevation angle, all for a given noise profile of the surrounding sky and ground. The computed radiation patterns and G/Ts are compared with measurements for several elevation angles and surrounding terrain     

基于差分进化算法的阵列天线波束赋形研究

在阵列天线波束赋形设计中,通常方法是对阵列的阵因子进行分析,这类方法没有考虑阵列单元的影响,所设计的波束形状与要求的有一定差异。本文将差分进化算法(DE)与高频电磁仿真软件HFSS相结合,分析阵中每个单元的影响,减少波束赋形结果与天线实际方向图之间的差异。文中对一个微带缝隙阵列天线进行了低副瓣优化设计,设计结果和HFSS仿真结果吻合良好,两者之间差异在0.3dB范围之内,验证了设计方法的可行性。     

基于QPSK的智能天线固定多波束基带DBF算法

射频(RF)波束形成算法,难以直接采用数字信号处理(DSP)技术,实时完成数字波束形成(DBF)计算.对于相移键控(PSK)调制方式,本文认为RF波束形成算法可等效在基带实现.针对四相相移键控(QPSK)调制方式,本文提出了一种新的智能天线固定多波束基带DBF算法.与RF波束形成算法相比,提出的算法可实现同样的辐射方向图,但需要的计算量却大幅度地降低.基带DBF算法,使智能天线的实现更为简单、应用更为灵活、性能更为优良,对推动智能天线技术实用化发展具有重大意义.     

A small dipole-fed resonant reflector antenna with high efficiency, low cross polarization, and low sidelobes

The computer-aided optimization of a small five-wavelength diameter reflector antenna with a center-supported dipole-disk feed is described. The primary radiation is controlled by using a patented beamforming ring to give low cross polarization and low sidelobes due to spillover. The efficiency is maximized by controlling and taking advantage of the multiple reflections between the feed and the reflector. This has inspired the name "resonant reflector antenna." The gain from the feed reflector resonances is so large that it compensates almost completely for the about 1 dB loss due to center blockage of the aperture.     

Development of a 45 GHz multiple-beam antenna for militarysatellite communications

Design and experimental results of a wide-angle coverage 45 GHz multiple-beam antenna for military satellite communications are presented in this paper. The high-gain spot beams with low sidelobe levels and efficient adjacent beam overlap are generated by employing an offset parabolic reflector with overlapping feed clusters. The beam shape can be adapted to cancel either single- or multiple-jammers by varying excitations within the feed cluster corresponding to the beam. Development of antenna components including Potter horn, polarizer, phase-amplitude controller, and beamforming network is discussed. Measured results of the demonstration antenna have shown that sidelobe and crosspolar levels of better than -25 dB are achieved for beams scanned over an eight-degree diameter circular coverage region. The adapted patterns of the antenna agree well with the computations, and null depths of better than 30 dB have been realized over a 4.5% bandwidth