TE /sub 11/ to HE /sub11/ Cylindrical Waveguide Mode Converters Using Ring-Loaded Slots

A theoretical parameter study is given of a TE/sub 11/ to HE/sub 11/ mode converter consisting of a section of cylindrical corrugated waveguide with ring-loaded slots. The analysis, using modal field-matching techniques to determine the scatter matrix of the converter, allows the return loss to be computed accurately. For a wide range of waveguide sizes it is shown that a bandwidth ratio of 1.5 with a return loss better than 30 dB is possible. The low-frequency performance of the converter is limited by the deterioration in return loss, while at high frequencies the generation of a small amount of unwanted EH/sub 12/ mode is the restriction. If the effects of this mode can be neglected, operation over a wider bandwidth is possible, particularly for larger waveguide size.     

Design of a New Wide Bandwidth TE<Subscript>01</Subscript>-Mode Converter

This study presents the design and cold testing of a Q-band TE₀₁-mode converter. Integrating Marie transducer and the design of Ching-Fang Yu and Tsun-Hsu Chang, we have improved the design of circular TE₀₁-mode converter. The working principle of each section are analyzed and discussed. Two identical converters are joined back-to-back to explore the field symmetry and to examine the existence of competing modes. The angle-independent transmissions manifest high mode purity. This converter features high back-to-back converting efficiency, high mode purity, compact converting section , and broad bandwidth (18% at a 1-dB transmission).     

圆波导TE01-TE11模式转换器设计与实现

基于耦合波理论的基础上,分析了TE01-TE11模式转换器的特性和半径渐变指数,讨论了中心轴线弯曲下的圆波导模式转换器,对中心频率33GHz的波导进行了模拟设计、仿真,在保证带宽的前提下,尽力降低转换器的长度和提高转换效率,最后达到了97．82％的转换效率,带宽达到2GHz。     

一种使用TE11为过渡模的TE01-HE11模式变换器设计

基于弯曲圆波导耦合理论和规则圆波导突变结构模式匹配法, 利用MATLAB软件编写的相关数值计算程序得到波导模式转换结构的优化参量, 最终使用CST软件对模型进行了仿真和验证.该系统主要由三部分组成: 一个TE01-TE01的过渡器, TE01-TE11和TE11-HE11的圆波导模式转换器.计算结果表明, 该TE01-HE11模式转换系统在24.13 GHz的频率有5%的带宽、转换效率超过了99%.计算结果、仿真结果和实物冷测结果是一致的.     

A mode transformer using fin-line array for spatial power-combiner applications

A new TE/sub 10/-to-TE/sub 20/-mode transformer has been developed on the basis of a fin-line array for waveguide spatial power-combiner applications. The fin-line array is designed such that the input TE/sub 10/ mode is split in space into multiple segments, then subject to different signal paths, which effectively converts the TE/sub 10/ mode into a TE/sub 20/ mode, while eliminating the TE/sub 10/ mode at the output. Our Ku-band (14-15 GHz) design indicates that the proposed mode converter makes it possible to obtain the TE/sub 20/ mode with greater than 22-dB suppression of the TE/sub 10/ mode over the band of interest. This converter was used in the design of a waveguide spatial power amplifier involving four monolithic microwave integrated circuit power chips and an output power of 31 dBm has been obtained with a combining efficiency of 80%. A measurement technique has been also developed to measure the electric-field profile inside the rectangular waveguide. A good agreement between measured and simulated results has been observed, showing an effective suppression of the TE/sub 10/ mode, as well as a good TE/sub 20/-mode formation judging from its amplitude and phase.     

A novel TEM-TE/sub 11/ mode converter

A novel mode converter that transforms coaxial transverse electromagnetic (TEM) mode to TE/sub 11/ circular waveguide mode is investigated. It is shown that with four metal plates inserted in the coaxial waveguide, the TEM mode will be converted to coaxial TE/sub 11/ mode, and finally, it forms a TE/sub 11/ conventional circular waveguide mode. The experimental test results are in good agreement with the computer simulations, which demonstrates the feasibility of the mode converter.     

Analysis and Design of TE/sub 11/-to-HE/sub 11/ Corrugated Cylindrical Waveguide Mode Converters

A theoretical parametric study is given of a TE/sub 11/-to-HE/sub 11/ mode converter consisting of a section of cylindrical corrugated waveguide with varying slot depth. The analysis makes use of modal field-matching techniques to determine the scatter marks of the mode converter from which we deduce its propagation properties. It is shown that a mode converter consisting of only five slots achieves a return loss better than 30dB over the band 2.7相似文献   

Circular TE/sub 0n/ Mode Filters for Guided Millimeter-Wave Transmission

A millimeter-wave circular TE/sub 01/ mode waveguide generates undesired circularly symmetric modes (TE/sub 02/, TE/sub 03/ modes, etc.) in bends or at discontinuities along a waveguide line. This paper describes the theory and experiment on the TE/sub 02/ and TE/sub 03/ mode filters developed for guided millimeter-wave transmission. The experimental results of two improved TE/sub 03/ mode filters show that the attenuation of the TE/sub 03/ mode is more than 16 dB for one type over the 40-70-GHz range. The TE/sub 01/-mode insertion loss of another type is about 0.2 dB over the 40-80-GHz range. The present mode filters can be applied to various high-speed guided rnillimeter-wave systems currently under development.     

94 GHz TE_（02）-TE_（11）模式变换链的设计与模拟

本文在电磁场耦合模理论的基础上利用MATLAB优化工具对W波段回旋管用TE02-TE01-TE11模式变换链进行了详细研究与分析。应用编制的仿真程序对W波段TE02-TE01-TE11模式变换链进行了设计和数值模拟,通过结构参数优化,获得了性能良好的模式变换链。TE02-TE01和TE01-TE11模式变换器在中心频率94 GHz处的转换效率分别为96.3%和94.1%,对应带宽分别为4 GHz（转换率95%以上）和2 GHz（转换率90%以上）。为了进一步验证设计的模式变换链的性能,利用高频模拟仿真软件HFSS对优化的模式变换链进行了模拟仿真,模拟结果与利用计算程序得到的结果基本吻合。     

Q波段圆波导轴线弯曲TE01-TE11模式变换器设计

在模式耦合理论的基础上, 采用相位重匹配技术对圆波导轴线弯曲TE01-TE11模式变换器进行了数值优化计算和分析.在Q波段给出了两种不同周期数TE01-TE11模式变换器的优化设计参数.数值计算表明: 四周期模式变换器的最高转换效率为98.82%, 带宽为2.2 GHz, 六周期最高转换效率为99.89%, 带宽为1.7 GHz.研究了模式变换器关键几何尺寸在小范围内变化对转换效率的影响.并利用HFSS对给出的模式变换器进行了仿真, 仿真结果与数值模拟一致性较好.同时加工了六周期结构模式变换器并进行了小功率热测实验, 测试结果表明输出了模式纯度较高的TE11模式.     

General TE/sub 011/-Mode Waveguide Bandpass Filters

A new structure for high-Q TE/sub 011/-mode circular waveguide cavities is introduced and shown to realize the most general bandpass-filter transfer functions. Methods of improving the mode purity and suppressing the degenerate TE/sub 111/ mode are presented. Several experimental narrow-bandpass filters having finite attenuation poles have been constructed; their measured responses show excellent agreement with theory. Average realizable unloaded Q's of 20000 and 16000 have been achieved at 8 and 12 GHz, respectively.     

Resonant Cavity Type Mode Transducer

This paper describes the operating principle and the properties of a resonant cavity type mode transducer which was newly devised. The theoretical equations necessary for designing the mode transducer from a TE/sub 10/ mode of a rectangular waveguide to an arbitrary mode of a circular waveguide have been derived, and a design method using the coupling parameters is discussed. The experiments were made for the rectangular TE/sub 10/-circular TE/sub 01/, mode transformation in the 50 Gc band. Showing an example (N=1), the transfer loss, input SWR and mode purity were 1.34 dB, 1.13, and 95 percent (power contents), respectively, at the resonant frequency of 50 Gc/s. The 3 dB bandwidth of the transfer loss was 83 Mc/s at the constant cavity length, but it can be made much larger if the cavity length is adjusted according to the frequency change. This mode transducer is unique in that various modes can be excited purely in the circular guide by merely varying the cavity length.     

Ka波段TE_（01）模回旋速调管带新型渐变段输出腔设计

利用正余弦拟合的方法和半径渐变波导的耦合波理论,设计出一种Ka波段TE01模回旋速调管带该新型渐变段输出腔。通过Matlab数值计算和HFSS仿真优化,研究了该新型渐变段的传输参数、反射参数、对杂模的抑制等性能指标。仿真结果表明：在渐变段长度为80mm、口径由14mm变化到32mm的情况下,在33～35GHz的范围内该新型渐变的传输参数大于-0.016dB,反射参数小于-55dB,对TE02模的耦合为-25dB和对TE03模抑制在-55dB以下;而该输出腔的中心频率为34.075GHz,Q值为109.6,工作模式TE01模式的模式纯度大于0.94。     

Bandwidth Enhancement in Dielectric-Lined Circular Waveguides (Short Papers)

The increase in TE/sub 11/-TM/sub 01/ mode bandwidth obtained by inhomogeneously loading (dielectric lining) a circular waveguide is systematically documented. Maximum bandwidth is about 31.83 percent of center frequency (up from about 26.54 percent for fully filled or empty circular waveguides). This makes circular waveguides competitive with square waveguides (bandwidth/spl aprox/ 34.3 percent) as radiators in wide-band dual-polarization arrays. Certain interesting symmetries involving the TE/sub 21/-TM/sub 01/ modal inversion are also examined.     

TE/sub 01/ Mode Components in the 3-mm Region

In the 3-mm region (94 Gc) it is desirable to use waveguide components operating in the low loss TE/sub 01/ mode in circular waveguide rather than in fundamental-mode rectangular waveguide. Because this is a higher mode, mode purity is of major concern. A method of identifying undesired modes and their amplitudes is by means of radiation patterns from the end of the waveguide. Components developed to operate in this mode include a transition from rectangular to circular waveguide, standing wave detector, variable attenuator, directional coupler, flexible waveguide, fixed 90/spl deg/ bend and rotary joint.     

X-band TM/sub 01/-TE/sub 11/ mode converter with short length for high power

A mode converter for X-band located between a generator and an antenna to convert TM/sub 01/ to TE/sub 11/ mode with high efficiency for a high power transmitting system is presented. The proposed mode converter has extended radius and excessive curvature with symmetric structure in order to convert between two modes efficiently with short length. The measured and simulated results of the return loss, mode patterns and efficiency of the proposed mode converter with 200 mm length are provided.     

Artificially integrated synthetic rectangular waveguide

A synthetic rectangular waveguide (SRW), which consists of two electrical sidewalls and two parallel periodical structures placed at the top and bottom surfaces of the waveguide, is presented. The SRW is made by multilayered integrated circuit processes, which typically have large ratios of SRW lateral dimensions to substrate thickness. Two theoretical methods, finite-element method and deembedding of composite structure consisting of SRW and mode converters, are applied to investigate the propagation characteristics of the SRW. Application of the dispersion characteristics of the two-dimensional periodical structures coupled with appropriate mode converter designs leads to results in SRW designs supporting TE/sub 10/, TM/sub 00/, and TM/sub 10/ modes. Measurements and the two theoretical approaches indicate that the slow-wave factor is 4.9 and Q-factor is 260 at 6.85 GHz for the TE/sub 10/ mode propagation with a cutoff frequency of 4.10 GHz (0.348 factor of cutoff frequency of conventional rectangular waveguide using the same material and dimensions). The theoretical data show the TM/sub 00/ mode to have a slow-wave factor of 1.8, Q-factor of 187.6 at 11.4 GHz, and cutoff frequency of 10.2 GHz. The TM/sub 10/ mode has a slow-wave factor of 1.98, Q-factor of 187.6 at 12.5 GHz, and cutoff frequency of 10.4 GHz.     

A high-efficiency quasi-optical mode converter for a 140-GHz 1-MW CW gyrotron

A highly efficient quasi-optical mode converter system with several novel features has been designed and tested at Forschungszentrum Karlsruhe (FZK). The converter consists of a dimpled-wall waveguide launcher, one quasi-elliptical mirror and two toroidal mirrors. The coupled-mode theory has been used to analyze the operation of the prebunching waveguide launcher; the radiated fields from the cut of the launcher have been calculated by the scalar diffraction integral. Simulation results show that the advanced dimpled-wall launcher generates a well-focused Gaussian radiation pattern with low diffraction losses. In this case, toroidal mirrors are sufficient to obtain a desired output beam pattern. An efficiency of more than 98% has been achieved to convert the rotating TE/sub 28,8/ cavity mode at 140 GHz into a fundamental Gaussian beam. Experimental measurements show close agreement with theoretical predictions.     

New dual mode square waveguide-corner

The design principles and method for a wideband dual mode square waveguide 90 degrees corner are presented. Experimental results show that for 22% relative bandwidth, the reflection loss in either the E or H-plane (TE/sub 01/ and TE/sub 10/ modes) is better than -27.5 dB.<>     

Gyrotron-traveling wave-tube circuits based on lossy ceramics

The gyro-traveling wave tube (gyro-TWT) is a microwave amplifier with simultaneous high power, high frequency, and broad bandwidth capabilities. Techniques for providing a controlled loading of the TE/sub 01/ cylindrical-guide operating mode of a 35 GHz gyro-TWT using monolithic, lossy ceramic structures are presented. The loading scheme, which also suppresses spurious backward-wave oscillations in the TE/sub 11/, TE/sub 21/, and TE/sub 02/ modes, is based on a sequence of alternating ceramic cylindrical shells and metal rings to form the electron beam tunnel. Design techniques for achieving optimal performance and methods for reducing the sensitivity to temperature-induced variations in ceramic dielectric properties are presented.