毫米波波导设计分析

在行波管整管性能中,波导与慢波结构的阻抗匹配过渡波导结构的S参数满足设计要求.采用两节腔慢波结构加载波导,模拟分析了无电子注作用时高频波的传输特性,分析得到引起衰减的主要因素并判定输入/输出波导与慢波结构的阻抗匹配状态良好.     

Millimeter Wave Substrate Integrated Waveguide Antennas: Design and Fabrication Analysis

The paper presents a new concept in antenna design, whereby a photo-imageable thick-film process is used to integrate a waveguide antenna within a multilayer structure. This has yielded a very compact, high performance antenna working at high millimeter-wave (mm-wave) frequencies, with a high degree of repeatability and reliability in antenna construction. Theoretical and experimental results for 70 GHz mm-wave integrated antennas, fabricated using the new technique, are presented. The antennas were formed from miniature slotted waveguide arrays using up to 18 layers of photo-imageable material. To enhance the electrical performance a novel folded waveguide array was also investigated. The fabrication process is analyzed in detail and the critical issues involved in the fabrication cycle are discussed. The losses in the substrate integrated waveguide have been calculated. The performance of the new integrated antenna is compared to conventional metallic, air-filled waveguide antennas, and also to conventional microstrip antenna arrays operating at the same frequencies.      

毫米波宽带波导功率合成器设计

毫米波宽带功率放大器是毫米波电子对抗系统的关键部件之一,宽带低损耗的波导合成器是实现毫米波宽带大功率合成放大器的关键。根据设计目标,分析比较了四端口波导合路器和无耗三端口波导合路器的优缺点,提出了毫米波宽带波导合成器的设计方案,用电磁场仿真软件HFSS对宽带波导功率合成器进行了建模和设计仿真,并制作了工作频率范围在26~40 GHz的功率合成器,对测试指标和仿真曲线进行了对比分析。实际测试结果表明,设计的波导合路器具有良好的工程实用价值。     

毫米波耦合腔行波管过渡波导的设计

利用电磁场分析软件，研究了用于毫米波耦合腔行波管的两种过渡波导，分析比较了各种结构的宽带匹配性能，给出的部分结果可以直接在整管设计中采用。     

Design of Millimeter Wave Wideband Transition From Double-ridge Waveguide to Coaxial Line

In this paper, an improved design method of millimeter wave wideband transition from double-ridge waveguide to coaxial line is introduced. The proposed design is based on the mode conversion theories and impedance matching techniques. The characteristics of the transition in microwave frequencies are analyzed and simulated by full-wave analysis software. According to the simulated results, a couple of transitions are fabricated. The predicted superduper performances have been confirmed experimentally in a wide frequency range of 18 ~ 40 GHz.     

The Groove Guide, a Low-Loss Waveguide for Millimeter Waves

A new waveguide for the low-loss transmission of millimeter waves is presented. The guide consists of two parallel conducting walls with grooves in the central region of the guide cross section. The grooves run along the guide in the direction of the wave propagation. It is shown that the waveguide, if excited in the TE-wave mode, has properties similar to those of the H guide, which contains a dielectric slab between the conducting walls in the center. The new guide is characterized by an exponential transverse decrease of the field distributions in direction from the center and by low attenuation. Theoretical considerations dealing with the field distribution and the data of the guide are presented.     

Random Discrete Imperfections in Millimeter Waveguide Systems

A method has been developed to compute the increase of attenuation due to imperfections of finite length randomly distributed in a link. As a limit for the vanishing length the formulas yield the result for random discontinuities. The approach is quite general and can apply to a circular waveguide link as well as to other cases, where the statistics of the problem are described by the power spectrum of the deformation. The applications presented here show how random spacing of the deformations causes significant modifications on the attenuation results; as a particular case some expressions are found to be in agreement with others previously derived. The results are interesting in determining what random variation in the waveguide lengths is sufficient to avoid a serious frequency dependent effect in the attenuation characteristic of a circular waveguide link.     

A Range of 2 and 1 Millimeter Waveguide Components

A variety of components have been made in wave-guides RG136 and RG139 by techniques which include the use of extruded waveguide, copper-gold eutectic bonding, precision milling and, in particular, of electroforming. Performances of several RG136 components are given, together with the loss in RG139 waveguide and in oversized guide tapered from RG139. Ferrite devices, including isolators, 3 port switches and amplitude modulators, using Ferramic R1, have been quite successful. A typical isolator has an insertion loss of 1 1/4 db and an isolation of 30 db, magnetically tunable over at least 133 to 145 Gc. An RG136 slotted line, at a coupling ratio of 20 db, has an inherent mismatch of 1.05 with good reproducibility over the 2 1/2 wavelengths traverse of the one-mil Wollaston wire probe. The main waveguide is milled and broached from brass and gold plated. Electroformed matched hybrid tees in RG136 split power to /spl plusmn/ 1/4 db, have a discrimination of 30 db, a loss of 1 1/4 db and a match looking into any arm of better than 1.4. Rotary and flap-type attenuators, phase shifters, variable short circuits, matching units, crystal diodes and their mounts, bolometers and dry calorimeters, etc., have been made, and for transmission over moderate distances the vastly overmoded TE/sub 01/ waveguide was used.     

波导微波泄漏检测系统的设计及实现

介绍了波导微波泄漏检测系统的原理，并对其中的幅度测量单元、显控单元的组成和实现作了详细的阐述。     

Hollow-Cylinder Waveguide Isolators for Use at Millimeter Wavelengths

The device considered in this study is a semiconductor waveguide isolator consisting of a hollow column of a semiconductor mounted coaxially in a circular waveguide in a longitudinal dc magnetic field. An elementary and physical analysis based on the excitation of plane waves in the guide and a more rigorous mode-matching analysis (MMA) are presented. These theoretical predictions are compared with experimental results for an InSb isolator at 94 GHz and 7.5 K.     

A New Leaky Waveguide for Millimeter Waves Using Nonradiative Dielectric (NRD) Waveguide-Part I: Accurate Theory

An almost-rigorous analysis is presented for a new leaky waveguide of simple configuration based on a recent nonradiative modification of H guide suitable for millimeter wavelengths, The analysis employs a transverse equivalent network that yields a dispersion relation in closed form, and contains some interesting and subtle features. Numerical values are presented for the phase and leakage constants in terms of the different geometric parameters and the dielectric constant comparisons with measurements are made in the companion paper, part II.     

一种新型毫米波集成波导微带转换的分析与设计

提出一种新型集成于单层微带基片的毫米波集成波导微带转换 ,由一圆形微带谐振器、微带共面波导探针组成。利用全波分析软件对该转换器进行了分析计算、优化设计。测试了波导微带转换实物 ,结果表明 ,在Ka波段在 1 GHz频带内 ,该波导微带转换具有较低的插入损耗 ( <0 .4d B)和反射损耗 ( <-1 4d B)。可满足相关毫米波微带集成电路系统的应用要求。     

Field Theory Design of Square Waveguide Iris Polarizers

Profiled depth corrugated square waveguide polarizers are designed with the method of field expansion into eigenmodes, which includes higher order mode interaction between the step discontinuities. Computer-optimized design data are giyen for a compact Ku-band prototype with an exponentially varying depth function that achieves 90° +- 1° differential phase shift shift within the separate 11.9-12.3-GHz and 17.5-17.9-GHz frequency bands. The maximum VSWR is only about 1.02. Further design examples include a linearly profiled depth function, which provides a short design, and a polarizer with iris thicknesses suitable for metal-etching manufacturing technique. The theory is verified by comparison with available measured results.     

A Novel Low-Loss Dielectric Waveguide for Millimeter and Submillimeter Wavelengths

This paper describes a novel dielectric (gas confined) wave guide which consists of a thin dielectric tube separating an internal high-dielectric-constant gas from an external low-dielectric-constant gas. The attenuation constant, fractional power flow, and radiation Ioss of this waveguide are calculated and compared with those of a conventional O-guide (a dieletric tube waveguide). The advantage of the gas-confined guide is that the attenuation constant is decreased involving no bending loss increase due to tight field confinement within the low-loss internal gas. Experimental investigations are carried out to verify the low-loss property of the gas-confined guide. An attenuation constant less than 0.4 dB/m is obtained over the 80-200-GHz range.     

On the Design of Transitions Between a Metal and Inverted Strip Dielectric Waveguide for Millimeter Waves

The results of a study of three types of transitions between the rectangular metal waveguide and the inverted strip guide are reported. Reflected power measurements from each type of transition and insertion-loss measurements for configurations involving the three transitions have also been carried out. The procedure of determining the optimum parameters for the transition is quite general, and has the potential for being extended to other dielectric structures.     

Power-Handling Capabilities of Circular Dielectric Waveguide at Millimeter Wavelengths

The power-handling capabilities of a circular dielectric waveguide propagating the single HE/sub 11/ mode are discussed. Simple calculations illustrate the limits imposed by dielectric heating and dielectric breakdown. Examples are presented for polystyrene and polytetrafluoroethylene (PTFE) guides at 70 GHz. The results suggest that maximum power levels for circular dielectric waveguide in the millimeter-wave specturm will be of the orders of 10 to 100 W and that dielectric heating is the limiting phenomenon.     

The Use of Flat Waveguide in the Millimeter Range

The use of flat waveguide in the millimeter range has the advantage of increased power handling ability and lower attenuation as compared to the ordinary single mode guide. These advantages are gained at the expense of possible multi-mode propagation. Various flat guide components are described which are designed to operate over a 4:1 frequency band with minimum higher mode excitation. In addition, the measurement of the equivalent coupling parameters of waveguide discontinuities when two modes are propagating, is discussed. These measurements are facilitated through the use of a novel standing wave indicator which allows the standing wave of each mode to be measured separately. The experimental values of the coupling parameters are in good agreement with those predicted by theory.     

Channel Multiplexing Network for a Millimeter Waveguide Transmission System

The Nippon Telegraph and Telephone Public Corporation (NTT) plans to make a field test for the practical application of the W-40G millimeter waveguide transmission system, using a frequency range of 43 GHz to 87 GHz and a clock frequency of 403 MBd. This paper describes channel multiplexing-demultiplexing networks fabricated for use in the test. First, frequency allocation and construction of the 43 ∼ 87 GHz multiplexing-demultiplexing networks are discussed. Second, newly developed hardware consisting of band-splitting filters and channel-dropping filters is described. Finally, overall loss, frequency response in amplitude and delay and pulse waveform transmission characteristics are shown. The overall losses of the networks constructed by three stages, namely, band-splitting filters (I), (II), and a channel-dropping filter, are 8 ∼ 12 dB over the frequency range from 43 GHz to 87 GHz, with the channel-dropping filters only partly installed. The experimental results suggest that these multiplexing-demultiplexing networks are suitable for the millimeter wave guided wave communication system.     

Impedance Characteristics of Closed Elliptic-Groove Waveguide for Millimeter Waves

A characteristic equation and impedance characteristic for the dominant mode of closed elliptic-groove guide have been analyzed and discussed by using the mode-matching method. The reference size of the closed elliptic-groove guide for the good impedance matching with rectangular guide in actual application is given. The obtained conclusions are of important significance in theoretical studies and actual applications of closed elliptic-groove guide for millimeter waves.