35 GHz Vivaldi Fed Antenna Design for Passive Millimeter Wave Imaging System in Ka Band

This antenna will be used for PMWIS （passive millimeter wave imaging system） which has 35 GHz operating frequency described as Ka Band. The antenna should work in that specific frequency because of having low attenuation in that region according to frequency behavior in misty conditions. Antenna also should have approximately 50 ohm input impedance value so that perfect matching to the active circuits will occur. The input reflection coefficient, S11, has to be under -20 dB and the gain of the antenna, has to be over 10 dB value for better efficiency. Microstrip Vivaldi Fed Antenna provides all of the conditions for imaging system, was designed by using Antenna Magus Computer Program and later it was designed in detail with Computer Simulation Technology Studio Suite Computer Program. The last format of the VFA has -23.1 dB input reflection coefficient, 48.55 ohm input impedance and 12.3 dB gain for 35 GHz OF. It is ready to connect to the LNA and detector, which are active circuits of the PMWIS. At the end, the detector will be connected to the VA and computer. The receiver of PMWIS is composed to the VFA connected to the other equipment that is defined above will scan elevation and azimuth angles, as a result; the VA will transfer the signals to the computer. Computer will show the user the scanning area image. In this system, antenna is the most important section and particular attention was given to the antenna in this study.

Design and Modeling of S Band Circular Patch and Ka Band Horn Antenna, Integration with Future Multifunctional Radio over Fiber Network

Radio over Fiber is an integration of microwave and optical fiber technologies having numerous benefits. RoF technology can give a scope of advantages including the capacity for backing multiple radio services and standards. In coming future, there is need of integrated wireless service with high speed satellite broadband and multifunctional indoor/outdoor antennas. Radio over fiber is one of the most favorite candidates to meet all these requirements of future multifunctional integrated wireless communication. Due to planer profile, small size and low cost patch antennas are most favorite to use for multi- frequency applications. In this paper, we present system level design for future multifunctional radio over fiber network. Under FTTH (Fiber To The Home) technology, it will be possible to use multi-frequency applications on single fiber medium. Firstly, we designed S band circular patch antenna (2.5 GHz) and Ka band (29 GHz) horn antenna. Circular patch antenna performance is estimated with different substrate height. After getting S parameters and far-field results, we did modeling of Radio over Fiber system over (10 Km) with same parameters from antenna results.

Coding Scheme for Ka-Band Fixed Satellite Communication System

The performance analysis and simulation of coding schemes based on the modeling Ka band fixed satellite channel have been presented. The results indicate that concatenated codes with large inner interleaving depth have good performance and high spectrum efficiency. The studies also show that simple block interleaving is very effective in combating the slow frequency nonselective fading of Ka band.

A Ku and Ka Dual Band Experimental Radar

Due to the good performance of tracking low elevation target as compared to microwave and the superiority in penetrating smoke, dust, fog, and dry snow as compared to infrared, a Ku and Ka dual band experimental radar was designed and developed. This Ku and Ka dual band experimental radar is an arnplitute-comparison monopulse tracking and guiding radar. The constitution and parameters of this radar is described in paragraph 2. Paragraph 3 deals with two experiments for testing the tracking performances against low elevation target, and gives the important results. Both Ku and Ka band have high tracking precision when they track high elevation targets, while Ka band has much better tracking performance than Ku band when they track low elevation targets. Ka band can track a helicopter, whose radar cross section is about 6 square meters, at 40m, 20m, 10m, and even 5m above sea. Ku band can only track the same helicopter at 160m and higher above sea.

Ka频段车载遥感站天线伺服控制系统设计

针对Ka频段7.3 m车载遥感站天线高精度标校、窄波束跟踪等应用需求,提出一种多数据源融合的跟踪控制方法。该方法采用双GPS/北斗定北和太阳标校相结合的角度校准方法,提高了天线捕获概率,解决了车载站天线难捕获以及车载站转场后伺服高精度角度标校的问题;综合利用天线系统中的接收机跟踪误差数据、程序跟踪点位数据、外部引导角度数据和天线实时角度测量数据,通过自适应加权最小二乘方法进行数据融合跟踪,提高了车载站天线伺服控制系统跟踪精度和跟踪性能。测试结果表明,组合标校方法实现天线外场角度标校精度优于0.02°;多源融合跟踪与单一数据源跟踪相比,伺服控制系统跟踪误差减小了30%以上,跟踪精度优于1/15个波束宽度。验证了组合标校和多源融合跟踪方法的有效性,可用于指导大口径高频段遥感接收天线伺服控制系统设计。

Ka频段卫通收发共口径多波束相控阵封装天线设计

为满足卫星通信中双频共口径、高集成、多波束等要求,提出了一种基于封装天线(Antenna in Package, AIP)架构的Ka频段收发共口径多波束相控阵天线。天线以双频堆叠微带单元的形式实现了收发共口径,并通过天线集成滤波器保证了收发通道的隔离度优于44 dB。在±60°范围内,64元接收阵增益优于17.4 dB,128元发射阵增益优于20.2 dB,具有良好的波束扫描性能。为获得收发多波束一片式集成,在收发(Transmitter/Receiver, T/R)组件中使用晶圆级三维系统集成封装(Three Dimensions System in Package, 3D-SIP)并结合微凸点的制备技术,保证了系统级芯片(System-on-Chip, SOC)的高密度二次集成。高低频混压技术同样被应用于阵面、收发网络、控制供电链路的多层板集成。所提多波束的相控阵天线新架构具有高密度集成TR组件、多波束一体化、高效散热等特点,在卫星通信和数据链等方面具有广阔的应用前景。

三个传输零点的三阶LTCC Ka-band窄带滤波器

本文介绍了一种基于LTCC(低温共烧陶瓷)技术的Ka波段三阶窄带滤波器,中心频率35.78GHz,带宽0.8GHz(2.24%),带内插损小于0.1dB(未考虑介质和金属损耗)。并且在输入输出端口、各枝节之间引入交调耦合分量,在带外形成三个传输零点,带外抑制EM仿真结果为:>20dB@f>36.9GHz,>30dB@f<34.9GHz。此滤波器可用于毫米波收发组件中,对镜频信号和杂波进行抑制。

Performance Analysis and Simulation of Higher Order Modulations for Ka-Band Fixed Satellite Communication

The performance analysis and simulation of spectrally efficient modulation schemes , MPSK and MQAM, for Ka-band fixed satellite communication system are provided. The effects of bandwidth limitation, nonlinearityity distortion and adjacent channel interference (ACI) in Ka-band satellite channel corrupted by additive white Gaussian noise (AWGN) are taken into account. The analytical expressions of the HER of coherent MPSK and MQAM signal are obtained and shown to be in good agreement with the simulation results.

A Ka-band Solid-state Transmitter Cloud Radar and Data Merging Algorithm for Its Measurements

This study concerns a Ka-band solid-state transmitter cloud radar, made in China, which can operate in three different work modes, with different pulse widths, and coherent and incoherent integration numbers, to meet the requirements for cloud remote sensing over the Tibetan Plateau. Specifically, the design of the three operational modes of the radar（i.e., boundary mode M1, cirrus mode M2, and precipitation mode M3） is introduced. Also, a cloud radar data merging algorithm for the three modes is proposed. Using one month＇s continuous measurements during summertime at Naqu on the Tibetan Plateau,we analyzed the consistency between the cloud radar measurements of the three modes. The number of occurrences of radar detections of hydrometeors and the percentage contributions of the different modes＇ data to the merged data were estimated.The performance of the merging algorithm was evaluated. The results indicated that the minimum detectable reflectivity for each mode was consistent with theoretical results. Merged data provided measurements with a minimum reflectivity of -35 dBZ at the height of 5 km, and obtained information above the height of 0.2 km. Measurements of radial velocity by the three operational modes agreed very well, and systematic errors in measurements of reflectivity were less than 2 dB. However,large discrepancies existed in the measurements of the linear depolarization ratio taken from the different operational modes.The percentage of radar detections of hydrometeors in mid- and high-level clouds increased by 60% through application of pulse compression techniques. In conclusion, the merged data are appropriate for cloud and precipitation studies over the Tibetan Plateau.

一种Ka频段宽带多波束相控阵的设计

【目的】全球已步入第5代移动通信技术(5G)和卫星互联网时代,各领域对通信速率和容量的需求激增,传统抛物面和窄带平面相控阵天线系统的应用受到带宽和波束形成数量等因素的限制。文章基于相关产业领域的现状、趋势和宽带多目标的应用需求,对Ka频段宽带多波束固态相控阵技术展开了研究。【方法】文章从理论上建立并推导了相控阵天线方向图的通用矢量数学仿真模型,研究了相控阵天线的子阵划分、孔径效应和渡越时间等问题,设计了基于阵元级电移相与子阵级光延时相结合的宽带多波束相控阵系统。前端单个集成子阵采用不同材料基板的三维高密度异构瓦式集成方案,极大地提高了子阵集成度;子阵后级采用基于光开关、高精度光纤延迟线和波分复用等技术相结合的光真时延(OTTD)方法,实现了子阵级的多通道延时和多波束合成。【结果】通过对Ka频段宽带多波束接收相控阵系统原理样机进行集成与测试,验证了原理样机克服了孔径渡越时间和波束偏斜等带宽限制问题。原理样机可实现对Ka频段8个独立接收波束的宽角度扫描,每个接收波束的最高数据传输率可达1500 Mbit/s。【结论】测试结果证明,文章所提系统具有集成度高、带宽大和可形成多个独立波束等优势。研究成果将有助于促进宽带多波束固态相控阵的进一步发展,为Ka频段宽带多目标相控阵的后续工程化和产品化奠定了理论和实践基础。

Ka频段全机动综合测控系统无人机标校设计与应用

任务前的系统标校和跟踪验证是Ka频段全机动综合测控系统需要完成的重要工作。Ka频段全机动综合测控系统机动性强,同时支持陆地机动测控和海上测控需求。系统布站位置灵活,布站地无标校塔,无法采用传统固定标校塔方法进行系统标校和跟踪验证。无人机平台机动灵活,搭载Ka频段信标机和校零变频器设备后,不仅可用于完成Ka频段全机动综合测控系统静态情况下的校相、距离校零和跟踪验证工作,还可满足系统机动测控情况下的跟踪验证需求。本文设计了无人机测试标校系统,满足Ka频段全机动综合测控系统在任意布站位置展开标校和跟踪验证工作,并进行了机动情况下的测控跟踪验证。经实测,“动中测”的测量精度满足要求,为机动型测控系统提供了一种新的跟踪验证手段,具有良好的应用前景。

Ka波段连续波9 W GaN功率放大器

本文研制了一款采用0.15μm碳化硅基氮化镓功率MMIC工艺的Ka波段连续波功率放大器芯片。功率放大器采用了3级共源级联结构。输出级采用了16个晶体管进行功率合成,有效地分散了热分布,输出匹配网络采用低损耗拓扑架构,保证了输出功率与附加效率。级间匹配采用了最大增益匹配,同时兼顾了小信号增益平坦度。在28 GHz~30 GHz内,小信号增益为25 dB,28 V偏置电压下连续波输出功率大于39 dBm,功率增益为17 dB,附加效率大于25%,热阻为1.41℃/W。输出功率为35 dBm时,IMD 3小于-25 dBc,芯片面积为3.0 mm×3.1 mm。

Ka波段双模螺旋线行波管的研制

本文介绍了一种Ka波段双模螺旋线行波管的研制情况,其工作频率范围为32~38GHz,工作电压为9.5kV,低模工作比为70%,峰值输出功率为150~200W;高模工作比为10%,峰值输出功率为300~400W。该Ka波段双模螺旋线行波管具有工作电压低、快速启动、可无环控工作的特点,适用于航外有源诱饵弹等多种应用场景。

一种Ka频段圆极化宽波束天线设计

文章针对常规频段越来越拥挤的频谱问题,突破思维定式,超越常规频段,设计了一种Ka频段圆极化宽波束天线。该天线主体辐射结构为单馈点圆极化方形贴片微带天线,并通过金属腔体扩展辐射波束。对天线的电性能进行了仿真分析,仿真结果表明:天线在29.5CHz~30.5CHz范围内电压驻波比小于2,在典型频点值30GHz下辐射右旋圆极化波,可以提高天线的抗干扰能力和接收信号的能力,天线的3dB波束宽度大于等于130°,是常规天线3dB波束宽度的两倍,可以在极广空域内辐射接收能量。

一种高集成八通道Ka频段低噪变频组件的研制

本文介绍一种高集成八通道Ka频段低噪下变频组件的功能和组成,研制了八通道Ka频段低噪下变频组件,提出了组件的工作原理和电路实现方式,对组件的隔离度、通道一致性、噪声系数、组合频率进行了分析。该变频组件测试结果为:噪声系数≤2.3 dB,变频增益≥35 dB,通道间幅度一致性≤±0.5 dB,多通道间隔离度≥60 dB,具有体积小、可靠性高、一致性好等优点,在某Ka频段测控系统的多波束引导接收中得到成功应用。

一种Ka频段双通道遥测设备的无杆标校方法研究

Ka频段双通道遥测设备的和、差通道存在相位差,并且随环境变化而变化,需要在基带终端通过校相才能实现相位差的校正,最终完成对目标的自主跟踪。在靶场中,以往都是通过架设标校杆进行基带校相,这种方法可以实现相位标校的目的,但是随着遥测设备作战领域已经向深海、高原等区域拓展,受到这些特殊位置环境等对架设标校杆的种种限制。本文重点研究了在高原环境下,不架设标杆校,通过偏馈天线发射信号,实现和、差通道相位零值标定的目的。本文给出了基于偏馈天线的无杆标校原理和方法,并通过实验验证了本文方法的有效性。

一次层状云弱降水过程的机载Ka波段云雷达探测特征分析

利用2019年11月17日一次层状云系弱降水过程中获取的机载Ka波段云雷达(Ka-band precipitation cloud radar,KPR)和云粒子测量系统(droplet measurement technologies,DMT)资料,将利用云粒子谱正演得到的雷达反射率因子(Z_(c))与KPR探测值(Z_(m))进行对比,并对影响两者偏差的成因进行探讨分析。结果发现:(1)在层状云内部,Z_(c)与Z_(m)有很好的一致性,两者之间的偏差和均方根偏差分别为4.1 dBZ和4.3 dBZ。(2)在KPR径向速度变化和速度谱宽较大的区域,或在云层比较薄的区域,Z_(c)与Z_(m)之间的偏差和均方根偏差变大,但在雷达反射率因子的变化趋势上有较好的一致性。(3)云粒子数浓度(N_(c))、云粒子有效直径和云中液态水含量的变化均对Z_(c)与Z_(m)之间的偏差有一定的影响,但偏差总体控制在±10 dBZ范围内。随着N_(c)的增大,两者之间的偏差变小,当N_(c)>200 cm^(-3)时,偏差大于10 dBZ的时次极少。当有效直径在50~230μm、液态水含量在0.15~0.50 g·m^(-3)范围内时,Z_(c)<Z_(m);当有效直径大于230μm、液态水含量大于0.50 g·m^(-3)时,Z_(c)>Z_(m)。

基于TSV技术的Ka频段硅基天线设计

TSV(Through-Silicon Via硅通孔)技术是现代集成电路设计的新型工艺。基于此工艺,针对射频通信系统小型化、高集成度的要求分别设计了工作于Ka频段的硅基多端口天线和单端口集成天线。整体结构采用CPW(Co-Planar Waveguide共面波导)和TSV结合的方式实现了对天线的馈电。在此基础上,分别设计了中心频率为35GHz的2X2四端口天线阵和中心频率为35.5GHz的单端口集成天线。仿真结果表明,天线阵列的相对带宽分别为2.88%和6.56%,增益约为4.57dBi和4.06dBi。

遥感卫星地面站12米口径天线Ka频段G/T值测试方法综述

Ka频段G/T值是遥感卫星地面站12米口径天线最重要的指标之一,其测试方法与遥感站目前常用的X频段测试方法相比,适用条件更加严苛,因此如何选取最佳的测试方法成为本文研究的主要内容。首先介绍了Ka频段12米口径天线特点;然后分别论述了分段测试法、信标法、比较法和射电源法的原理及其优缺点,并提出了Ka频段对月测试的这一最方便简洁的测试方法及其修正系数的研究方向;最后通过实测结果进行比较,给出Ka频段G/T值测试方法选取建议,为工程师现场测试提供了科学的指导和参考。

Ka波段自偏置微带环行器优化设计与仿真分析

基于BaM型六角铁氧体材料,利用有限元仿真软件建立微带环行器的三维电磁场模型,优化仿真设计Ka波段自偏置环行器的结构和尺寸,探究铁氧体基板厚度h、中心圆盘半径R_(0)以及大小Y结尺寸对环行器性能的影响。结果表明,在26~28GHz频率范围内,插入损耗S_(21)随着铁氧体基板厚度h增大而增大,隔离度S_(12)和回波损耗S_(11)随铁氧体基板厚度h和中心圆盘半径R_(0)先增大后减小;随着大小Y结长度和宽度的增大,回波损耗S_(11)和隔离度S_(12)均先增大后减小。经优化仿真后,在26~27.6GHz频率范围内,环行器插入损耗S_(21)均小于1dB,最小插入损耗为0.85dB,最大隔离度为53dB,隔离度S_(12)和回波损耗S_(11)均大于20dB的带宽约1.6GHz,器件整体尺寸为7mm×7 mm×0.4mm,具有良好的环行性能。