基于深度学习的毫米波系统波束成形

针对高移动用户在毫米波系统中用户与基站之间频繁切换增大延迟开销问题,提出了一种新颖的集成深度学习协调波束成形(Deep Learning Coordinated Beamforming,DLCBF)解决方案.该方案通过协调多个基站同时为一个移动用户服务,接收用户上行导频序列和预编码码本训练模型,进而预测最佳下行波束向量...     

Analysis of Complex Dielectric Phase Gratings by Hybrid FEM-Gaussian Mode Expansion Technique

Hybrid technique of finite element method (FEM) and Gaussian mode expansion method is implemented for the analysis of transmission property of dielectric phase gratings used in holographic power combining systems. It takes advantages of the versatility of FEM and the simplicity of the mode expansion method. Apparently, this hybrid method is well suited for the analysis of phase gratings with complex profiles, which provide more degrees of structural freedom than those of classical rectangular groove gratings. The transmitted fields of an array of two and three fundamental Gaussian beams through the multi-stepped and curved gratings are calculated by the hybrid method. Numerical results show that much less phase distortion can be fulfilled for the reconstructed pseudo-plane wave by the modified phase gratings, especially the curved ones. This is advantageous for improving the combining efficiency in spatial millimeter wave and sub-millimeter wave power combining systems.     

基于SIW的多波束CTS阵列天线设计

文中设计了一款基于基片集成波导(SIW)的毫米波高增益多波束连续横向枝节(CTS)阵列天线,它通过切换馈电端口实现多波束功能。该天线整体结构简单,采用印刷电路板工艺实现。天线主要包含馈电喇叭、平面波转换结构以及辐射结构三个部分,由三层基板构成。馈源为基于SIW的馈电喇叭,并在口径处添加匹配结构以提高其辐射性能;平面波转换结构由SIW抛物面和渐变耦合槽组成,可将馈电喇叭辐射出的柱面波转换为幅度服从泰勒分布的平面波进而为CTS阵列馈电,因此天线具有低副瓣的特性;辐射结构为1×8的CTS阵列,通过优化缝隙宽度以保证每个单元辐射出相等的能量。天线工作在30 GHz,通过切换馈电端口可在±20°范围内实现波束切换,天线测试结果与仿真结果吻合,验证了设计的合理性。     

毫米波扩展互作用器件

扩展互作用器件是一种采用慢波谐振系统作为高频互作用电路的真空电子器件,是目前能够在毫米波亚毫米波段提供大功率输出的重要器件之一。本文给出了目前国内外毫米波亚毫米波段扩展互作用器件（EIK和EIO）技术的发展情况,并介绍了扩展互作用器件在毫米波亚毫米波段的技术特点和最新研究趋势。     

毫米波有源相控阵天线技术

概述了毫米波技术在雷达探测及通信领域中的应用优势、使用场景以及未来的技术发展趋势,并着重对其技术实现面临的难点进行分析。同时,针对应用需求和技术特征的不同,介绍了满足各类应用的毫米波相控阵技术发展的不同技术路线,对其中涉及的架构、天线单元、器件和封装集成等主要关键技术进行了阐述,力图从总体上对其技术体制、应用情况和发展趋势进行科学分析和归纳,为毫米波相控阵天线技术的发展提供借鉴。     

The Ratio of Antenna Heights as a Parameter to Characterize Path Loss: A Millimeter Wave Desktop Propagation Study

This paper contains measured data for desktop propagation path loss at millimeter wave band. Different ratios between transmitting antenna height and receiving antenna height were studied based on a vector network analyzer system. Transmitting and receiving antenna were separated by distances ranging from 5 to 300 cm on a wooden desktop, and the antenna heights were varied from 5 to 25 cm. Average path loss data are coupled with the path loss exponents and the breakpoint locations of piecewise model to provide insight into large scale propagation characteristics of desktop millimeter wave communication systems. These measurement results may aid in the development of future short range wireless propagation in millimeter wave bands.     

Densification of Alumina Ceramics Sintered by Using Submillimeter Wave Gyrotron

The sintering of high purity alumina, by using a very high frequency in range sub-millimeter waves, is presented in this paper. The sintering was performed by using a 300 GHz material processing system. Achieving homogeneous and volumetric heating on submillimeter wave sintering was confirmed by the grain size distribution analysis. The densification curves were obtained for submillimeter wave (300 GHz), millimeter wave (28 GHz), and conventional processing. The enhancement of densification and early shrinkage were observed on submillimeter wave sintering. However, compared with millimeter wave method, the densification of sub-millimeter wave sintering is lower at all sintering temperatures. The grain coarsening was analyzed using SEM photographs of fracture surfaces. The grain sizes of submillimeter wave sintered samples were smaller than those of the millimeter wave sintered samples. The effect of cold isostatic pressing, was also evaluated on submillimeter wave sintering. It suggests that the cold isostatic pressing method is quite effective for densification of SMMW sintering alumina.     

毫米波亚毫米波近场天线测量系统的建设

随着天线工作频段的扩展以及实际应用的需求,越来越多的科研单位投入了对毫米波甚至到亚毫米波天线的开发,毫米波亚毫米波天线测量系统也成为了研发过程中不可或缺的设备,本文将主要针对测试频率高于40GHz 的系统,从暗室系统的建设、系统机械扫描架的建设、RF 子系统的搭建、系统综合测试性能的评测以及实际建设的系统方面来 对毫米波亚毫米波系统的建设提供参考性意见,以期为需要建设类似系统的科研单位提供理论和实际的工程参考。     

微波管器件现状及技术发展分析

综述了国内外几种主要的微波真空功率器件技术的发展现状,特别对微波管CAD技术、短（亚）毫米波器件、阴极技术等进行了分析,并对整个微波管行业面临的挑战和机遇进行了讨论。     

Design of High-Performance Millimeter Wave and Sub-Millimeter Wave Quasi-Optical Isolators and Circulators

Faraday rotators using permanently magnetized ferrite materials are used to make quasi-optical isolators and circulators at millimeter wave and sub-millimeter wave frequencies that have far higher performance than their waveguide equivalents. This paper demonstrates state-of-the-art performance for four-port quasi-optical circulators with 60-dB isolation, 0.2-dB insertion loss, and better than 80-dB return loss for devices centered at 94 GHz. A method is presented for the accurate characterization of the complex permeability and permittivity of permanently magnetized ferrites via a series of frequency and polarization dependent transmission and reflection measurements. The dielectric and magnetic parameters for the sample are determined by fitting theoretical curves to the measured data. These fitted parameters are then used in a model for a complete quasi-optical Faraday rotator, including matching layers, allowing the accurate design and fabrication of these devices for any specific operational frequency band in the millimeter wave and sub-millimeter wave regime. Examples are given showing typical results and demonstrating how temperature cycling can significantly improve the temperature stability of these devices, while allowing fine tuning of the center frequency. We also indicate the performance possible at higher frequencies to above 1 THz and outline performance of truly planar isolators where lossy polarizer material is built into the Faraday rotator matching structure     

A Future Millimeter/Sub–Millimeter Radiometer for Satellite Observation of Ice Clouds

The instrument concept of a future spaceborne millimeter/sub-millimeter radiometer is proposed in this paper for the remote sensing of ice clouds from satellite. The proposed radiometer is expected to operate at a series of frequencies within the millimeter and sub-millimeter wave range from 150 to about 900 GHz. Five frequencies are selected in the atmospheric windows, i.e., 150, 220, 463, 683, 874 GHz, and at each frequency there are two orthogonally polarized channels. Three water vapor channels located close to 183.31 GHz are also included in this instrument, since they can provide water vapor information, which is needed for ice cloud parameter retrieval. To simplify system design and test, a modular design philosophy is followed in the receiver frontend design and two antennas are used separately for the millimeter and sub-millimeter channels. Overall, the instrument requirements can be met with today's technology, except for the channels at the highest frequencies, where the radiometric sensitivity can be larger than the required 1.0 K for the 10 km spatial resolution (2.5 ms integration time). However, this situation can be improved by averaging neighboring pixels in data processing if certain compromise in the spatial resolution can be made at these frequencies.     

Design and experimental investigation of a multibeam integrated reflector antenna of the millimeter wave band

A multibeam integrated reflector antenna operating in the millimeter wave band is considered. The antenna consists of a radiating array, a planar mirror, and a multichannel feed. The results of simulation of a radiating array of slots in a metal screen are presented. The array is manufactured on the basis of a medium with forced refraction, including a double-slot array, which can radiate along the normal to the array plane. Operation of the array in the multibeam mode is analyzed. It is shown that application of a medium with forced refraction increases the array aperture efficiency in this mode. The results of the design of a planar two-layer mirror are presented and the mirror’s quality indices are estimated. A multichannel radiator designed as an array of planar H-plane horns is studied. The results of simulation of such a radiator with the help of an approximate technique and numerical solution of an electromagnetic problem are considered. The design of the multibeam antenna and its experimental characteristics are presented.     

毫米波相控阵天线研究

阐述了国内外毫米波相控阵天线技术的发展现状,介绍了相控阵天线的原理,指出了实现毫米波相控阵天线的技术关键。并给出了目前的技术条件下实现毫米波相控阵天线的途径。     

微波毫米波多芯片模块三维互联与封装技术

微波毫米波固态有源相控阵天线在通信、雷达和导航等电子装备中得到广泛应用,三维互联与封装技术是研制小型化、高集成和高可靠有源相控阵天线的微波毫米波多芯片模块(MMCM)的关键技术。通过开展三维多层多芯片热布局优化设计,使MMCM 温度分布均匀,保证三维MMCM 可靠工作。通过研发含有双面高精度腔体的低温共烧陶瓷(LTCC)多层电路基板,并采用球栅阵列(Ball Grid Array, BGA)和毛纽扣微波毫米波垂直互联工艺、激光密封焊接工艺,研制出小型化、高性能和高可靠性的三维微波毫米波多芯片模块,满足新一代微波毫米波相控阵天线技术要求。     

任意槽形矩形慢波结构高频特性分析

矩形慢波结构及其变态具有易于微加工、横向尺寸大、散热好等优点,是一种有潜力工作于毫米波段或亚毫米波段的高频系统.文中利用场匹配的方法推导出了任意槽形状开放式矩形波导慢波结构的统一色散方程,并利用数值计算方法分析了几种特殊槽形状加载慢波结构的色散特性及耦合阻抗,得到三角形结构色散和耦合阻抗均最弱,而倒梯形结构色散最强,耦合阻抗最大.     

具有空间宽带效应的毫米波3D MIMO信道估计

在现有的大规模三维多输入多输出（3D MIMO）系统中,相邻天线间的距离可能非常大,这往往会导致电磁波穿过阵列孔径时出现物理传播延迟,被称为空间宽带效应。而大多数学者在研究信道估计时为方便通常会忽略它,仅仅有学者研究雷达系统时提到了空间宽带效应。而去年有学者将其引入到了2D MIMO毫米波系统中,本文在此基础上将其扩展到了毫米波大规模3D MIMO系统中,基于平面天线阵列的水平角和垂直角设计了一种新的信道模型,并提出了一种信道估计算法,仿真结果表明其具有良好的信道估计性能。      

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。     

Design and experimental study of a planar multibeam double-reflector aplanatic system

The results of design and experimental investigation of a multibeam planar three-layer double-reflector system in the millimeter wave band are presented. A Schwarzschild aplanatic reflector system with symmetric generatrices is considered. The system parameters have been chosen as a result of optimization of this system with the use of the method of physical optics and the Pareto criterion. A prototype of an integral quasi-optical system in the form of a multilayer printed circuit board containing an aplanatic double-reflector optical system illuminated by an array of 19 microstrip horns has been manufactured. Experimental studies have been performed at a frequency of 36 GHz; a set of beams with fan-shaped radiation patterns in a coverage sector of ±38° has been obtained. The experimental data are compared to the results of calculation.     

大功率毫米波雷达及器件新技术研究

近年来,在电真空技术进一步发展和概念创新的基础上,借助于材料、工艺及微加工技术的进步,大功率毫米波器件取得了快速发展,诞生了大功率毫米波回旋行波管、W波段宽带行波管、准太赫兹行波管、毫米波扩展互作用速调管、集成微型行波管等新管型。在毫米波频段取得了输出功率100 W^100 kW、带宽6~10 GHz等标志性成果。利用上述性能优良的电真空器件结合雷达探测新技术,开展毫米波单脉冲精密测量及目标成像雷达、毫米波空间合成无源相控阵多目标监视雷达、毫米波微型行波管有源相控阵多功能一体化雷达、机载亚毫米波视频合成孔径雷达研究,突破大功率毫米波器件应用和发射机关键技术,实现大功率毫米波雷达空间目标的多维特征精细测量和成像等应用目标。