电磁偏谐振阻抗匹配宽带传输超表面设计

针对传统传输超表面固有高Q值导致的工作频带窄的问题,提出了一种电、磁双模偏谐振阻抗匹配实现宽带传输超表面设计方法。建立了实现低损耗透波阻抗匹配的本征参数模型,并根据经典Drude-Lorentz模型分析了本征参数在电磁谐振与偏谐振区域的电磁特性。基于此,通过独立激励电、磁偏谐振模式,设计了满足宽频带阻抗匹配的本征参数电路模型。基于该模型,通过在超表面中引入金属微带线和平行贴片分别作为电、磁偏谐振器,调控结构的本征参数,从而在宽频带内实现所需本征参数条件。仿真和测试结果均证明,设计的超表面实现了双极化模式相对带宽为79.5%的3 dB传输带宽,且结构具有0°~40°的斜入射稳定性。该超表面具有超宽带、结构简单的特点,可应用于高性能天线罩设计中。     

采用一维物理光学法的天线罩瞄准误差补偿

针对雷达天线罩瞄准误差的补偿问题，提出了一种适用于各向同性的天线罩瞄准误差修正方法。构建了基于一维物理光学法的天线罩瞄准误差的数学模型，推导了雷达导引头测量目标角度和角速度的误差修正公式。试验结果表明，该方法有效降低了天线罩瞄准误差对目标角速度性能的影响。     

基于柔性LCP基板的SIW带通滤波器设计与实现

液晶高分子聚合物(LCP)以其优异的高频特性而被广泛应用于高频无源器件设计以及封装基板制备.文章利用LCP基板设计并实现了一款结构紧凑、中心频率20 GHz、相对带宽为30％、带内损耗小于2 dB的基片集成波导(SIW)带通滤波器.通过在SIW谐振腔短边垂直方向引入微扰金属通孔,实现了谐振腔主模中心频率从16 GHz上...     

Optimization of two-dimensional radome boresight error performanceusing simulated annealing technique

A systematic approach to radome design is presented. The problem is formulated as a global optimization procedure such that the radome performance is optimized by properly adjusting the thickness of the radome layer over the entire radome surface. In this approach the thickness profile is parameterized via B-splines representation. Simulated annealing technique is applied to finding the best thickness profile so that the maximum boresight error is reduced to as small as possible over the entire range of the antenna look angle. A two-dimensional design example is given. The best possible thickness profile is found and the boresight error is reduced considerably compared to that due to a uniform layer. The method is general and can be applied without difficulty to other realistic three-dimensional radomes of arbitrary shapes     

一种基于超材料的谐波抑制天线罩

设计了一种基于超材料结构的前置谐波抑制单元天线罩,该天线罩采用多层互补型亚波长单元结构,在一个天线单元的有限尺寸范围内排列更多的周期单元,减小边缘效应的影响,天线罩总厚度小于5 mm,通过PMI泡沫与喇叭天线连接。采用激光刻蚀工艺制备了不同尺寸的两种试验件,并进行了超材料的传输系数测试以及带罩天线阵谐波抑制性能测试,结果表明,所设计的超材料谐波抑制天线罩具有带内0.3 dB 的插损,二次谐波20 dB和三次谐波30 dB的抑制能力。     

Ka波段宽频带频率选择表面设计

随着毫米波技术的发展和毫米波天线的广泛应用,提出了对毫米波雷达隐身的要求。基于耦合和谐振原理,设计了一种Ka波段带内透过的单层频率选择天线罩。利用谱域法对频选天线罩进行了分析计算。优化得到的天线罩仿真结果在Ka全波段内平均插入损耗小于1 dB,在45毅扫描角内35 GHz的S21 >-1. 7 dB,实现X 波段和Ku波段内的透过率小于-11 dB。最后,对频选罩的相关参数特性进行了分析,便于针对其他电性能要求进行优化改进。     

Design of Ka-band antipodal finline mixer and detector

This paper mainly discusses the analysis and design of a finline single-ended mixer and detector. In the circuit, for the purpose of eliminating high-order resonant modes and improving transition loss, metallic via holes are implemented along the mounting edge of the substrate embedded in the split-block of the WG-finline-microstrip transition. Meanwhile, a Ka band slow-wave and bandstop filter, which represents a reactive termination, is designed for the utilization of idle frequencies and operation frequencies energy. Full-wave analysis is carried out to optimize the input matching network of the mixer and the detector circuit using lumped elements to model the nonlinear diode. The exported S-matrix of the optimized circuit is used for conversion loss and voltage sensitivity analysis.The lowest measured conversion loss is 3.52 dB at 32.2 GHz; the conversion loss is flat and less than 5.68 dB in the frequency band of 29-34 GHz. The highest measured zero-bias voltage sensitivity is 1450 mV/mW at 38.6 GHz,and the sensitivity is better than 1000 mV/mW in the frequency band of 38-40 GHz.     

A high-performance 2—18.5-GHz distributed amplifier—Theory and experiment

A high-performance 2-18.5-GHz monolithic GaAs MESFET distributed amplifier has been designed and fabricated. The distributed amplifier is analyzed theoretically using a normalized transmission matrix approach, and a closed-form gain equation is presented for the MMIC m-derived drain-line case. Theoretical predictions are compared to measured results and more complicated CAD models. The measured small, signal gain is typically 8.0±0.40 dB from 2-18.5 GHz at standard bias. Typical input return loss is greater than 12 dB, and the output return loss is greater than 15 dB. The saturated output power is in excess of 23 dBm over most of the band, and the noise figure is less than 7.5 dB.     

Low Conversion Loss Mixers with Improved Finline Transition and Bandstop Filter

A Ka-Band hybrid integrated single-ended mixer with low conversion loss is designed in this paper. In the proposed circuit architecture, metallic via holes are implemented along the mounting edge of substrate embedded in the split-block of WG (waveguide)-finline-microstrip transition. Simulated results show that the effect of high-order modes due to the mounting groove is effectively eliminated and the transition loss is greatly improved. Meanwhile, a slow wave and bandstop filter at Ka band, which presents an equivalent short circuit, is designed for the maximized utilization of idle frequency energy, RF and LO signal energy. In this way, the conversion loss of the mixer can be further improved. The lowest measured conversion loss 3.52dB is obtained at 32.2 GHz; the conversion loss is flat and less than 5.68dB over the frequency band from 29 to 34 GHz. Supported in part by National Natural Science Foundation of China (NSFC) under Grants 60621002 and in part by NSFC under Grants 60471017.     

Accurate boresight measurements of large antennas and radomes

A laser-mirror system incorporated into an antenna pattern range is capable of aligning the antenna tower to measure the radome boresight error of large antennas to within 0.1 mrad angular accuracy. The simplicity of the alignment system makes it relatively easy to position the antenna, with or without its radome to a preestablished mechanical reference plane. Hence, deflection of the antenna tower system due to different loadings can be determined which otherwise would be undetected with most range facilities.     

X波段交直流分离的MEMS开关的设计与研究

介绍了一种带直流驱动电极交直流分离的MEMS开关,研究了影响开关阈值电压的因素,运用缩腰设计、尺寸优化等方法降低开关的阈值电压;运用阻抗匹配方法降低开关的反射损耗;利用等效电感的设计提高所需频段的隔离度。使用Coventor和HFSS软件模拟,设计的开关阈值电压小于20V,在X波段插入损耗低于0.1dB,反射损耗低于-25dB,谐振点处隔离度高于40dB。     

Design of a 24-40 GHz balanced low noise amplifier using Lange couplers

A wide band(24-40 GHz)fully integrated balanced low noise amplifier(LNA)using Lange couplers was designed and fabricated with a 0.15/zm pseudomorphic HEMT(pHEMT)technology.A new method to design a low-loss and high-coupling Lange coupler for wide band application in microwave frequency was also presented.This Lange coupler has a minimum loss of 0.09 dB and a maximum loss of 0.2 dB over the bandwidth from 20 to 45 GHz.The measured results show that the realized four-stage balanced LNA using this Lange coupler exhibites a noise figure(NF)of less than 2.7 dB and the maximum gain of 30 dB;moreover,a noticeably improved reflection performance is achieved.The input VSWR and the output VSWR are respectively less than 1.45 and 1.35 dB across the 24-40 GHz frequency range.     

X波段阶梯阻抗微带带通滤波器设计

设计了一款X波段的多模带通滤波器,并给出了仿真与实验结果。采用恒定阻抗枝节加载3个阶梯阻抗枝节的方式,构成滤波器的主体;利用表面电流分布图获得影响带内极点分布的枝节参数,通过调整阶梯阻抗枝节参数优化滤波性能。为实现更好的带外抑制能力,滤波器两端各串联一对平行耦合线,在14 GHz引入一个传输零点。实验测试结果显示,所设计滤波器的中心频率为9.76 GHz,带宽为2.4 GHz,30 dB/3 dB矩形系数为1.63,相对带宽为25%,带内插入损耗大部分小于1 dB,大部分回波损耗高于15 dB,与仿真结果较为吻合。     

基于遗传算法对二维天线罩瞄准误差的优化

基于物理光学法及表面积分法计算了二维相控阵天线罩的瞄准误差并利用遗传算法对瞄准误差进行优化。首先建立二维相控阵天线一罩系统的数学模型并对瞄准误差进行分析计算,并在此基础上利用遗传算法对天线罩的壁厚分布进行编码以实现对瞄准误差的优化。     

半模SAFSIW谐振腔耦合带通滤波器设计与实现

空气隙填充基片集成波导(Slab Air-Filled Substrate Integrated Waveguide,SAFSIW)作为一种新型的导波结构,被广泛应用于毫米波传输线以及无源电路的设计,由于SAFSIW 中空气隙的存在,其相较于传统的SIW 具有更高Q值。本文基于半模双腔耦合SAFSIW 设计并实现了一款中心频率为19 GHz 的带通滤波器。为了改善滤波器的带外抑制,通过给谐振器并联枝节线结构,在滤波器的上边28 GHz 处,引入一个传输零点,大大改善了滤波器的带外抑制特性。利用双面覆铜的LCP 基板进行了滤波器的加工,并对其进行测试。测试结果表明,该滤波器中心频率为19 GHz,相对带宽达18%,插入损耗优于-4.2 dB,回波损耗小于-16 dB。由于上边带传输零点的引入,该滤波器在28.5 GHz 时,上边带抑制达到-36 dB 以下。实物测试相比于仿真结果有一定的恶化,主要原因是由于SMA转接头带来的损耗以及HMSAFSIW谐振腔的加工误差所导致。     

基于CSRR-QMSIW谐振器的双通带滤波器的设计

为满足滤波器在双频带通信系统中发展的要求,提出了一种基于1/4模基片集成波导(QMSIW)加载互补开口谐振环(CSRR)的新型双通带滤波器。根据CSRR谐振器的传输特性,实现以其谐振频点为中心的第一个通带;设计QMSIW谐振腔的边长,实现以该腔体谐振频点为中心的第二通带;设计QMSIW腔体间的耦合方式,在两通带之间和高阻带处各引入一个传输零点,加强两通带隔离度和带外抑制。设计了一款两通带的中心频率分别为8.1 GHz和11.5 GHz,且有效尺寸仅为15 mm×8 mm,插入损耗低于0.4 dB,高阻带衰减达64 dB,两通带隔离度达46 dB。     

A multielement high power monopulse feed with low sidelobe and high aperture efficiency

A multielement high power monopulse feed was investigated for excitation of a phased array. This feed has the advantages of high antenna efficiency, effective independent sidelobe control for the sum and difference patterns, and high power handling capability. A 32-element device has been designed which yields theoretical sidelobe levels less than -31 dB for both the sum and difference patterns over the 2800 to 3200 MHz frequency band. The aperture efficiency is 69.5 percent which includes 0.1 dB spillover loss and 1.40 dB tapering loss. The difference slope efficiency defined as the actual slope gain over the maximum possible value is 50 percent at midband. An experimental feed was constructed to verify the predicted performance characteristics. Measured data on both the radiation patterns and the antenna gain agreed very Well with the analytical results. The measured sidelobe level is below -30 dB for all sum and difference beams over the 2800 to 3200 MHz. In addition, this feed can be designed for low power intensity at the feed aperture so that very high power operation can be attained.     

Dual Band Planar Spiral Feed Backed by a Stepped Ground Plane Cavity for Satellite Boresight Reference Antenna Applications

This paper presents development of a new planar spiral feed for a satellite boresight reference antenna, operating at two widely separated frequency bands (2200–2300 MHz and 8000–8400 MHz). A stepped ground plane cavity with different quarter wavelength distances is proposed to provide unidirectional patterns at these frequency bands. A back lobe suppression of around 12 dB in 2 GHz band and better than 15 dB in 8 GHz band with a measured on-axis axial ratio of less than 3 dB is achieved for the dual band planar spiral feed with stepped ground plane cavity configuration. A boresight reflector antenna employing this feed has measured beamwidths of 7 degrees and 1.8 degrees respectively and gain of 26 dBi and 36 dBi at 2250 MHz and 8200 MHz.      

面向高铁卫星通信系统的高性能天线罩设计

设计了一款适用于高铁平台卫星通信相控阵天线的高性能天线罩.该天线罩针对载体应用环境，设计了双向对称、低剖面的气动外形，以满足载体高速双向对开时低空气阻力的要求；同时根据卫星通信相控阵天线波束扫描的特点，设计了变厚度夹层结构，以实现天线罩对任意极化方向的电磁波宽角入射时高透波率的电性能.以Ku频段为例，根据设计结果进行了实物制作和测试验证，测试结果显示在10.5~13 GHz频率范围内，采用垂直极化波和水平极化波分别照射时，天线罩在0~70°的入射角范围内，透波率均保持在80%以上，同时天线罩对相控阵扫描波束的指向误差维持在±0.5°范围内.