双频带隔板极化器

介绍了一种双频带隔板极化器的设计思路及其应用实例.这种极化器应用了隔板极化器的双频带特性,在一个很宽的频带内实现了圆极化性能,轴比性能良好,且体积小、重量轻,可以在带宽比较窄的前提下实现收发共用,解决了一些小型天线对微波网络重量和体积限制的问题.     

栅条型与网格型极化器

本文给出两种由印制板组合的极化器——一为栅条型;一为网格型。前者单点频率特性好,后者具有宽频带特性。对于波导喇叭馈源,可将极化器做成平板状,罩在辐射口面前。文中给出的曲线和公式有助于简化设计计算。实验表明,栅条型极化器在20％的频带内驻波比小于1.1,圆极化轴比优于2dB,网格型极化器在不小于20％的频带内驻波比小于1.1,轴比优于1dB。     

8 GHz～18 GHz波纹方波导移相器的研究

波纹方波导圆极化器是常用的圆极化器,波纹方波导移相器是它的关键组成部分.文中以路的方法对波纹方波导移相器进行了分析,计算了周期长度内相移量的宽频带特性和波纹方波导各个尺寸对驻波比的影响.应用电磁仿真软件对8 GHz~18 GHz波纹方波导移相器进行了优化,最后在整个频带内得到的相移量为90°±12°,驻波比小于1.1.加工后与其他零件装配成圆极化器,经过测试,在整个频带内轴比小于3 dB.     

8-18GHz介质板极化器的分析与设计

介质板极化器在天线设计中的应用非常广泛。从介质板波导形成圆极化波的原理出发,推导出差相移与波导传播常数的关系式。因此只需利用数值方法计算波导的传播常数,从而减小了仿真计算量。分析表明在818GHz超宽带范围内,方波导中插入介质板的圆极化轴比理论上只能达到2．03dB。文中提出介质板插入结合波导口径变形的方法使圆极化轴比小于1．53dB,驻波比小于1．23。对介质板波导的关键参数进行误差分析,得到加工误差对圆极化性能的影响小于2．5％。     

宽带式隔板极化器

介绍一种宽频带隔板极化器的设计原理、设计思路及其设计实例。这种极化器具有频带宽、轴比小、圆极化端口隔离度高及体积小的特点。对其功率容量的高频仿真表明他能承受较大功率。他可广泛用于微波馈电网络系统。     

高阶圆波导模式圆极化器的研究

提出了一种基于光滑圆波导结构的高阶TEmn模圆极化器.运用耦合波理论和数值计算方法对93 GHz TE5,1模圆极化器进行了研究和设计.设计的圆极化器由过渡段和移相段组成,结构简单,易于实现.在88~98 GHz的频带内,最大轴比低于1.18.空间辐射测试结果证明了这种高阶圆极化器的性能.为高性能的低阶波导模式圆极化器的设计提供重要参考.     

宽带高性能四脊波导圆极化器设计

在射电望远镜和卫星通信天线中,圆极化器是关键部件之一。传统圆极化器在保证0.75 dB轴比时的相对带宽最多为41%,无法满足日益增长的宽频带应用需求。该文利用四脊波导的宽带特性,通过采用具有不同尺寸的水平脊和垂直脊,使四脊波导两个正交主模的相位常数不同,来实现宽带移相特性,并给出了一种宽带四脊波导圆极化器的设计方法。按照这一方法,设计了一款宽带C波段圆极化器,工作带宽为3.625～7.025 GHz,相对带宽64%。该文还研究了圆极化器主要参数变化对其性能的影响,加工并实测了一个圆极化器样机。实测结果显示出,该圆极化器两个正交极化的反射损耗均小于–21 dB,相差90°±3.8°,相应的轴比小于0.6 dB。测试与仿真结果吻合良好,证明了分析与设计方法的正确性。     

一种新型双频双圆极化复合微带天线设计

针对空间微波能量收集的应用场景,提出了一种微带线行波激励的双端口双频双圆极化复合微带天线。该天线由一个工作在低频段的微带圆环和一个工作在高频段的微带圆片复合而成,分别由两种不同的正交十字缝隙耦合馈电,采用微带线级联依次相差90°顺序旋转四馈电实现圆极化,通过对称性结构设计,分别从两个不同端口输入获得双圆极化性能。实验结果表明：在880～960 MHz和1.85～2.45 GHz频带内S11<-10 dB,阻抗相对带宽分别为8.7%和30%;在885～920 MHz和1.86～2.43 GHz频带内轴比小于3 dB,圆极化相对带宽分别为4%和29%;天线的方向性在工作频段内良好,在低频段增益达到5.4 dB,在高频段增益达到7.7 dB。该天线结构紧凑且加工简单,为双端口双频双圆极化天线的研究与设计提供了新思路。     

一种CPW馈电圆形缝隙宽带圆极化天线

设计了一种共面波导(CPW)单端口馈电的圆形缝隙宽带圆极化(CP)印刷天线。该天线通过在圆形缝隙侧面附加圆形枝节,结合CPW端口伸出的激励带条,激励出一对相位差90°的差分正交简并模,从而辐射圆极化波。对天线模型进行了优化设计和实物加工,测试结果表明,该天线的轴比带宽(AR<3dB)达到12.5%;最大增益为3.8dB,在轴比带宽内增益的变化幅度小于1dB。     

一种基于电调移相器的可重构天线

设计并实现了一种基于反射式移相器的极化可重构天线。该天线使用一对交叉摆放的领结型振子作为辐射单元,并在馈电网络中通过两路移相器调整双馈端口间的相位差实现线极化、左旋圆极化和右旋圆极化模式之间的切换。通过加载匹配枝节的方法扩展了反射式移相器的移相范围,提高了移相器的移相精度,降低了天线圆极化模式带内的轴比。所设计天线的中心频率为5.4 GHz,在线极化模式下10 dB 阻抗带宽为990 MHz,在圆极化模式下10 dB 阻抗带宽分别为760 MHz 和850 MHz,3 dB 轴比带宽分别为510 MHz和480 MHz。该天线在频带内具有稳定的波束方向图,其平均增益为5.3 dB,并且具有27 dB 的主极化-交叉极化隔离。最终的实测结果与仿真结果基本一致,表明该天线具有良好的性能。     

多层曲折线圆极化器的研究

对多层曲折线圆极化器进行了研究,描述其分析方法和设计方法。给出理论和实验结果,证明了这种四层曲折圆极化器可以在倍频程范围内得到良好的低轴比、低损耗特性。     

基于模式搜索法的折线栅圆极化器的优化设计

应用微波等效网络方法，分析了在两种场型激励下单元折线栅对应的传输参数矩阵；采用网络级连方法，分析了多层折线栅对应传输参数矩阵，进而推导出折线栅极化器的传输系数和两正交分量的轴比；最后以8～12GHz通带内轴比均值为目标函数，优化了4层折线栅圆极化器的结构参数，优化结果与HFSS计算结果进行了比较，二者吻合。     

The Analysis of a Broad-Band Circular Polarizer Including Interface Reflections

Transmission characteristics of a broad-band circular polarizer consisting of anisotropic dielectric plates are rigorously analyzed. The transmitted wave is formulated in terms of the incident wave including interface reflections. The influence of the interface reflections on the axial ratio of the polarization is numerically shown vs frequency. Frequency dependence of the power transmission ratio is also obtained. From the above analysis, it can be concluded that a circular polarizer of this type is promising as a new broad-band circular polarizer.     

Wideband reflecting frequency-selective surface polarizer for X-band applications

This paper proposed the design of a broadband linear-to-circular reflecting polarizer for X-band applications. The polarizer is designed with three-arm dipole-shaped unit cells with a full ground plane to get wideband performance. The incident linear polarized wave is converted to a right-handed circularly polarized wave upon reflection from the polarizer. The footprint of the unit cell is 9 × 9 mm, which is printed on a FR-4 substrate. Fabricated prototype is measured for its performances like polarization conversion ratio (PCR), fractional bandwidth, and aperture efficiency. The PCR is about 97%, and the fractional bandwidth is 64% with the aperture efficiency of more than 80%. Polarizer performance is analyzed in transverse electric and transverse magnetic modes, and they are stable up to 40° of various incident angles. The polarizer exhibits the 3-dB axial ratio bandwidth from 8 to 12 GHz, which is suitable for satellite applications.     

High‐Performance Dual‐Circularly Polarized Reflector Antenna Feed

This paper presents a high‐performance dual‐circularly polarized feed employing a dielectric‐filled circular waveguide. Novel features are incorporated in the proposed feed, such as a dielectric rod radiator for high gain and good impedance matching; dual quarter‐wave chokes for low axial ratio over wide angles and for low back radiation; an integrated septum polarizer; and two end‐launch‐type coaxial‐to‐waveguide transitions. The proposed feed shows excellent performance at 5.0 GHz to 5.2 GHz.     

脊波导缝隙圆极化天线的设计*

设计了一种新型脊波导缝隙圆极化天线。在脊波导宽边开并联纵缝,从波导耦合电磁波至其上方的四脊波导圆极化器,实现圆极化辐射。采用脊波导不仅减小了单元尺寸,更改善了天线的带宽性能。重点研究了四脊波导圆极化器对相互垂直的两辐射场分量的影响,优化单元的轴比特性。在提取单元谐振电导的基础上,设计了工作在10GHz 的1×10 圆极化波导缝隙阵列。对天线实物测试得到中心频率处的增益为16.8dB,第一副瓣电平为 25dB,阻抗带宽约为8.5%,相对轴比带宽(AR臆3dB)约为3.2%。     

Constructing the phase converters consisting of arbitrary number oftranslucent surfaces

An effective analytical method of synthesis of an artificial anisotropic structure has been developed. At a design frequency, it ensures perfect match and a phase shift given. The structure may be formed by arbitrary number of inductive and capacitive grids. The method has been applied to constructing circular polarizers and twist polarizers. The geometrical parameters of the polarizers were found in the explicit form. Analytical criteria for an estimate of the bandwidth of the devices have been derived. Performance of the polarizers over a frequency band was studied. A circular polarizer has been proposed which consists of both a cascade of two inductive grids and a cascade of two capacitive grids. The polarizer can be used when very high axial ratio is needed. It ensures more than 10% bandwidth for 0.99 axial ratio. Measurements have been presented that prove adequacy of the mathematical model for real inductive and capacitive screens