平面漏波天线综述北大核心CSCD

综述了平面漏波天线最近的发展情况。主要介绍了微带漏波天线和基片集成波导(SIW)漏波天线,探讨了这些漏波天线的工作模式,介绍了这些天线的理论分析与设计方法,描述了这些天线的传播特性及辐射特性。     

用区域分解法分析基于NRD波导结构的漏波天线

提出了利用区域分解结合频域有限差分法,分析基于NRD波导结构的漏波天线。用区域分解法将原问题分解为若干子问题,大大缩小稀疏矩阵的规模,从而使得求解大尺寸问题成为可能。文中首先介绍了区域分解法在分析三维电磁问题中的实现,并计算了典型结构金属块的散射问题,用于验证算法的正确性;最后分析了一种基于NRD波导结构的漏波天线,并与实验值进行了比较,说明了方法的有效性。同时还给出了一种能够有效改善该天线性能的改进型漏波天线结构的分析结果。     

镜象和非镜象型喇叭NRD漏波天线的研究

为了克服一般无辐射介质波导漏波天线(简称 NRD 漏波天线)在 xoz 平面上有两个对称大瓣的缺点,也为了提高天线的增益,作者曾提出在天线口面上加喇叭的方法,称为喇叭 NRD 漏波天线。本文从理论上解出了当喇叭张角较小时(不大于50度)喇叭 NRD 漏波天线的复传播常数,从而可以设计天线。文中给出了根据理论结果计算的相位常,数β及衰减常数α随喇叭张角θ_0及介质条位置 d 的关系曲线。理论计算数据及实验结果符合良好。本文并提出了镜象型喇叭 NRD 漏波天线的方案,使天线的面积及体积大大减小,也解决了介质条的安装及固定的问题,将这种天线向实用化推进了一大步。同样也求出了镜象型喇叭 NRD 漏波天线的复传播常数,并得到了实验验证。     

NRD波导缝隙天线中横向辐射现象的研究

本文对NRD波导裂缝天线横向辐射现象进行了深入的研究.给出了一种分析波导缝隙横向辐射能量空间分布的有效方法.研究结果不仅对开放波导激励的缝隙天线的设计有实际意义,而且对以缝隙作为耦合结构的集成电路的研制,特别对抑制由横向辐射造成的干扰的研究有着重要的指导意义.     

基于复合左右手材料的圆柱共形漏波天线设计

提出了一种基于复合左右手材料的平衡式圆柱共形漏波天线。天线单元由圆柱共形介质波导构成,通过在波导上表面蚀刻矩形缝隙槽结构,在引入串联电容的同时实现电磁波能量的连续泄漏,从而得到所需要的辐射特性。同时在波导结构中采用金属化通孔,引入并联电感, 实现了电磁波的左手传输特性。所设计的天线在平衡频点 15.6 GHz 处具有良好的边射特性。所提出的复合左右手漏波天线的阻抗带宽为 4.3 GHz(13.5~17.8 GHz),在天线阻抗带宽范围内天线主波束可以从-57°连续扫描到+30°。     

基于特异材料微带漏波天线辐射特性研究

分析复合左右手特异材料微带漏波天线的辐射原理,建立复合左右手材料微带漏波天线仿真模型,通过仿真计算得到微带漏波天线的辐射特性。制备与仿真参数相同的实物天线,测量天线S参数、方向图和天线各单元电容瞬态电压。最后,对仿真试验结果和实物天线测量结果比较,吻合较好。在固定工作频率下,复合左右手特异材料微带漏波天线工作在左手区时,电磁波辐射主要发生在天线结构前几个单元,且电磁波以指数形式快速衰减,工作在右手区时,电磁波沿整个天线辐射,且电磁波衰减较慢。     

一种基于左手介质的新型介质栅漏波天线的理论分析

提出了一种基于左手介质的新型介质栅漏波天线,并采用多模网络与严格模匹配相结合的方法,对该左手介质栅天线的辐射特性进行了仔细严格的分析.文中给出了漏波系数随天线结构参数变化的关系以显示该左手介质天线特有的性质.数值结果表明这种新型漏波天线比传统介质栅天线具有更强的辐射能力.讨论了产生这种现象的原因.     

基于漏泄矩形波导的低副瓣漏波天线

设计了一种基于长直缝隙漏泄矩形波导的低副瓣漏波天线.基于有效辐射段理论将漏波天线等效成线源模型,分析线源模型的有效辐射段结构,然后针对天线某一副瓣对应的有效辐射段,缩小该处的缝隙宽度直接抑制该副瓣水平,同时通过增大天线主瓣对应的有效辐射段缝隙宽度间接抑制副瓣水平.两种方法都能不同程度实现天线的低副瓣特性,利用仿真软件验...     

基于Minkowski分形CRLH结构的微带漏波天线

将Minkowski分形理论应用于文献中提出的复合左右手传输线结构,使其带宽从2.78～3.30 GHz展宽到2.02～4.53 GHz.对新结构色散特性进行分析,给出色散曲线,确认其为平衡结构,并在此基础上设计了一款微带漏波天线.由于复合左右手单元结构具有左手和右手特性,漏波天线可以分别实现后向辐射和前向辐射,在平衡状态下,消除了平衡点附近的阻带效应,平衡点处的群速不为0,有行波传播,天线可产生横向辐射.仿真和测试结果表明,该文所设计的漏波天线工作频段为2.35～3.20 GHz,相对带宽为30.6％,且能实现从后向到前向连续辐射,克服了传统漏波天线后向辐射角和前向辐射角不连续的缺点.     

可重构天线的FDTD研究

基于共面波导漏波结构,提出了一种方向图可重构的天线结构,该天线采用开关重构漏波结构周期,并使用两个馈电端口.采用时域有限差分法(FDTD)对天线的可重构特性进行了仿真分析.计算结果表明该方法能快速准确地确定周期结构漏波天线设计中的关键参数-基波传播常数.     

A Systematic Investigation on Leaky Characteristics for NRD Guide with Arbitrary Profile of Cross-Section

The leaky characteristics of the NRD guide with arbitarary profile of cross section are systematically studied by a method which combines staircase approximation with multimode network theory and mode-matching procedure. Emphasis is laid on the investigation of the effect of the different profile dimensions on the leakage characteristics of the NRD guide. Extensive numerical results are given to establish useful guidelines for the design of some new types of NRD guide leaky wave antennas.     

Leaky wave antenna based on image NRD guide with staircase-shapeddielectric slab

A leaky wave antenna based on the use of an asymmetric image nonradiative dielectric (NRD) guide has been studied experimentally. By using a staircase-shaped image NRD guide, the gain bandwidth of the antenna becomes three times that of a leaky wave antenna using an ordinary image NRD guide. Moreover, this antenna employs a flared horn in the NRD guide which makes the H-plane beamwidth controllable     

Leaky NRD guide as a feeder for microwave planar antennas

Although leaky wave antennas have been studied extensively in the literature, their practical use is still limited. This work proposes a novel and unique application of leaky NRD guides as feeding systems for microwave planar antennas and shows their substantial possibilities of practical use. At first a new leaky waveguide is introduced based on a periodic array of grooves on the upper side of the dielectric strip in the NRD guide. Then, leaky waves issuing from this configuration are used to feed a slot array cut on the upper metal plate of the NRD guide. Design examples of linearly and circularly polarized planar antennas were constructed, and their characteristics were measured at 23 GHz. The obtained results show the validity for this application of the leaky waveguide     

Analysis of Transmission Characteristics for NRD/Microstrip Line Hybrid Integrated LSE and LSM-Mode Baluns*

The NRD/microstrip line hybrid integration structure shows good behavior for millimeter wave applications. This paper applies the integral equations method to analyze the transmission characteristics of the NRD/microstrip line hybrid integrated baluns coupling through slot and operating in LSE or LSM modes. To apply this method, a new Greens’ function of microstrip line is presented and the slot coupling problems between NRD guide and microstrip line and the practical LSE and LSM-mode baluns are analyzed respectively. The availability of the present approach is validated by rather good agreement between the theoretical results and the experiment data given in the literature.     

Full-wave nonlinear analysis of nonradiative dielectric guide circuits including lumped elements

This paper describes the full-wave numerical analysis of complex nonradiative dielectric (NRD) guide structures including linear or nonlinear lumped elements. The numerical results described in this paper, validated through experimentation, show that the method is suitable for NRD guide and similar circuits. Nonlinear analysis of a single-ended NRD guide mixer is carried out, and the results are experimentally verified. Nonlinear harmonic-balance analysis of a novel leaky-wave balanced mixer circuit with very good tolerance of manufacturing inaccuracies in NRD guide configuration in Ka-band is then carried out. Due to curved segments, and orders of magnitude difference in the dimensions of different parts, the analysis of this component requires certain simplifying assumptions. How these can be implemented without sacrificing much accuracy is described. Until now, the design of NRD guide components, especially those using nonlinear effects, has been mostly trial-and-error-based. Here we demonstrate that a more systematic approach is possible.     

Analysis and measurement of NRD-guide leaky wave coupler in Ka-band

A new structure for a nonradiative dielectric (NRD) waveguide directional coupler has been developed. The structure combines two NRD guides and a dielectric slab guide in order to utilize a leakage mechanism for coupling. The coupling depends on this leaky mechanism, but not on field interactions as in a conventional proximity coupler. A theoretical formula for calculation of the decay constant is derived. The field along the NRD guide and the decay constant are measured at Ka band (35 GHz) and compared with the theoretical data. Reasonable agreement between the measured and theoretical data is found     

Substrate integrated nonradiative dielectric waveguide

A new substrate integrated circuits (SICs) fabrication technique is proposed for realizing nonradiative dielectric (NRD) waveguide circuits. This new technique called substrate integrated NRD (SINRD) guide allows the NRD guide be integrated within a dielectric substrate by drilling a pattern of air holes. Dispersion analysis and design considerations of the new structure are discussed. A hybrid integrated scheme of planar and SINRD circuits is demonstrated for the first time with simulation and measurement results.     

An NRD-fed dielectric rod antenna for the short millimeter wave band

A simple E-plane tapered rectangular dielectric rod fed by NRD guide is used as a millimeter wave antenna. This class of aerial features attractive radiation patterns with relatively low sidelobes and moderate gain. The measured results show that such an antenna and mounting structure can be exploited as effective radiating element in the short millimeter wave frequency band.     

An NRD fed dielectric rod antenna for the short millimeter wave band

A simple E-plane tapered rectangular dielectric rod fed by NRD guide is used as a millimeter wave antenna. This class of aerial features attractive radiation patterns with relatively low sidelobes and moderate gain. The measured results show that such an antenna and mounting structure can be exploited as effective radiating element in the short millimeter wave frequency band.     

Leaky Characteristics of Modified NRD Guide with Finite Parallel Plate Length

Leaky wave characteristics of modified NRD (Nonradiative Dielectric) guide with parallel plate length are systemically investigated. A technique is used to investigate the leaky property of the guide structure, whichis formulated by effectively combining the multimode network theory with the mode-matching method. In the paper, two phenomena are carefully studied: First, the asymmetric position of the dielectric rod generates a leaky hybrid mode that could produce cross talk between components of the circuit. Second, when the length of metallic plate is finite, another type of leaky mode creates which influences and even couples to the normal leaky guide mode under appropriate circumstances.