A broadband MM wave helix-waveguide coupler

A millimeter wave helix-waveguide coupler has been investigated. The experiments show that the wider bandwidth matching was obtained by the designed coupler in Ka band.     

Design of Coupling Structure for MMW Folded Waveguide TWTs

A significant advantage of the folded wave traveling wave tube (TWT) is simple coupling structure. In millimeter wave band, owing to higher frequency, linear double taper can be used as impedance transformer. The design method and calculation results for the folded waveguide TWTs in Kα-band are given.     

Analysis of Performances for Broadband Millimeter Wave Folded Waveguide TWTs

On the basis of computation of dispersion and coupling impedance for folded waveguide circuit (FWC), main performances: interact coefficient, saturated gain and output power are analyzed. Computation shows that if FWC is used in MMW amplifier, high power and wide band can be easy reached.     

一种用于毫米波的共面波导间的宽带互联结构

在多芯片组件中,微波传输线间一般使用金丝键合的方式进行连接。受金丝自身的等效电感和其与基板及壳体间存在的寄生电容的影响,键合金丝结构在毫米波频段下带来了较大的阻抗失配。为了解决该问题,文中从等效集总元件角度出发,对阻抗变换公式进行了推导,分析得出串联低阻抗传输线可以等效为并联集总电容的结论,可以与键合金丝的等效模型一起,构成等效低通滤波器,完成阻抗匹配。文中使用共面波导结构制作了键合金丝匹配结构测试件,测试结果显示,在30～40 GHz内S_(11)<-20 dB、S_(21)>-0.2 dB,具有优良的传输性能。该结构具有较强的实用性,可以用于毫米波频段下的微波组件设计。     

Double ridged waveguide phase shifters for broadband applications

The author presents an electromagnetic mode matching analysis of dual ridged waveguide phase shifters. The waveguide is loaded with a high dielectric material between the ridges, and the troughs are filled with ferrite toroids. The present structure offers nearly twice the bandwidth and less variation in nonreciprocity versus frequency as compared to the conventional dual toroidal phase shifter. An optimum design that maximizes nonreciprocity has been found. Effects of the dielectric constant and the trough dimensions are also presented. A differential phase shift of more than 100°/cm has been predicted for the new phase shifter     

一种紧凑型的宽频带单脊波导功分器

提出一种宽频带、小型化单脊波导功分器结构。分支波导采用标准单脊波导,在维持较高功率容量的条件下拓展了传输模的主模带宽。在T型结处设置一容性金属平板与分支单脊波导相接构成一个宽带电抗性调谐元件,在主模带宽拓展的情况下有效地实现了T型结的宽带匹配。为了能够与标准器件连接,设计了单脊波导-标准矩形波导转换器件,采用多级阶梯匹配的形式使转换器件的阻抗带宽与T型结保持一致。利用高频仿真软件HFSS进行仿真优化,结果显示该功分器在25~40 GHz频率范围内,回波损耗小于–20 d B,信号波动优于0.04 d B,相对带宽为46.2%,实际内部尺寸比标准波导功分器减少38%。该单脊波导功分器具有低损耗、小型化和宽频带的优点,可以广泛应用于雷达、天线以及功率放大器等微波设备。     

W-band broadband integrated circuit mixers

Broadband integrated circuit mixers using a crossbar stripline configuration and a finline configuration have been developed. For the crossbar stripline balanced mixer, less than 7.5 dB conversion loss for 15 GHz instantaneous IF bandwidth has been achieved with the LO at 75 GHz and the RF swept from 76 to 91 GHz. For the finline balanced mixer, a conversion loss of 9 to 12 dB over a 19 GHz instantaneous IF bandwidth has been achieved as the RF is swept from 91 to 110GHz.     

Nonradiative dielectric waveguide circuit components

The nonradiative dielectric waveguide (NRD-guide) is a newly proposed dielectric waveguide which can substantially suppress radiation at curved sections and discontinuities and is applicable to great advantage for millimeter wave integrated circuits. Basic circuit components such as transitions between a metal waveguide and an NRD-guide, matched terminations, a ring resonator and a bandpass filter were fabricated with polystyrene material and tested successfully at 50 GHz. Measurements showed that each component worked as expected without suffering from undesirable radiation and interferences at all.     

High-speed circuit designs for transmitters in broadband data links

Various high-speed techniques including internal peaking, differentially stacked inductor, and dual-loop PLL for wireline communications are proposed,analyzed, and verified by means of three independent circuits. A multiplexer incorporates multiple peaking techniques and gate control switching to achieve an operation speed of 20 Gb/s while consuming 22 mW from a 1.8-V supply. A voltage-controlled oscillator employing differentially stacked inductor accomplishes a phase noise of -90dBc/Hzat 1-MHz offset with a minimum power of 1 mW. A clock multiplication unit utilizes dual-loop architecture as well as a third-order loop filter, arriving at an output jitter of 0.2 ps, rms (0.87 ps, rms de-embedding 0.84 ps, rms from the instruments) and 4.5 ps, pp while consuming 40 mW from a 1.8-V supply.     

A RF window for broadband millimeter wave tubes

The equivalent circuit and design method for a RF window in millimeter wave band are presented. Computation and experiment show that matching band of the RF window is wider. It can be used as output window for broadband millimeter wave tubes.     

New NRD guide MM wave oscillators

A new millimenter-wave Gunn oscillator is described. The present structure makes use of NRD guide and metal resonant cap. The field expressions and the design considerations of NRD guide are discussed. Some experimental results of 8mm and 6mm band oscillators show that the new Gunn oscillator has a future as an integrated millimeter-wave source.     

Central-pin tolerances in broadband 3-port waveguide circulators

Computed designs for broadband 3-port waveguide designs are discussed. They require a central metallic pin of very small diameter within the ferrite. The computed effects of pin tolerances are shown.     

Analysis of the methods to increase the output power and frequency of the broadband TWTs

The limitations on the output power and operating frequency of the broadband TWTs resulting from a relatively low thermal stability of helix and the self-excitation at the backward wave at a operating voltage of greater than 10 kV are considered. The analysis yields the methods to overcome limitations: the application of a bifilar helix with the azimuthally conducting rings and the application of combined metal-dielectric supports that allow a simultaneous improvement of the heat removal from the helix and an increase in the TWT band. It is demonstrated that a decrease in the slowing caused by the rings and a smaller period of the bifilar helix make it possible to shift the threshold of the self-excitation at the backward wave to 30–40 kV.     

毫米波行波管用衰减瓷

针对毫米波行波管用衰减瓷,就衰减瓷在复合粉体制备工艺、微观结构和材料性能测试等方面作了详细论述.     

A step-type, broadband, X-band ceramic waveguide window

This paper describes a broadband-type ceramic output window for use in X-band microwave power tubes. This vacuum-tight window is capable of passing average cw power outputs of more than 250 watts, and can withstand temperatures as high as 750°C. The window introduces a standing-wave ratio of less than 1.2 over a frequency range of more than 2,000 megacycles per second, and, due to lengthening of the arc path, shows little tendency toward arc-over.     

Equivalent circuit formulation for an array of phased waveguide apertures

An expression for the radiation admittance of an infinite planar array of rectangular waveguide apertures is formulated and a technique for finding the complete equivalent circuit of the waveguide to space junction is given. The formulation includes multiple layers of dielectric above the array ground plane and waveguide elements which are center loaded with dielectric. Experimental verification of the radiation admittance formulation and the equivalent circuit concepts is given.     

An expandable time-division circuit switching LSI and networkarchitecture for broadband ISDN

A broadband network architecture is proposed that integrates multimedia services, such as data, video, and telephony information, using 52-Mb/s based STM-paths at the user network interface (UNI). The user can access any new service via the STM-based access network via either synchronous transfer mode (STM) switching or asynchronous transfer mode (ATM) switching. STM circuit switching supports long duration, constant bandwidth data transfer services such as video and high-definition television (HDTV) distribution and will also be used for the crossconnect system. Circuit switching can provide transparent transmission during long connection periods. This paper also proposes an expandable time-division switch architecture, an expandable time-division switching LSI, and an expandable switching module for small to large size system applications. The proposed time-division switching LSI, module, and system handle 52-Mb/s bearer signals and have throughputs of 2.4 Gb/s, 10 Gb/s, and 40 Gb/s, respectively. The time-division switch realizes video distribution with 1:n connections. Finally, a local switching node that features an expandable 52-Mb/s time-division circuit switching network is shown for multimedia access networking     

A novel noncontacting waveguide backshort for submillimeter wave frequencies

A novel noncontacting waveguide backshort has been developed for millimeter wave and submillimeter wave frequencies. It employs a metallic bar with rectangular or circular holes. The size and spacing of the holes are adjusted to provide a periodic variation of the guide impedance on the correct length scale to give a large reflection of rf power. This design is mechanically rugged and can be readily fabricated for high submillimeter wave frequencies where conventional backshorts are difficult or impossible to fabricate. Model experiments have been performed at 4 GHz – 6 GHz to empirically optimize the design parameters. Values of reflected power greater than 95% over a 30% bandwidth have been achieved. A specific design is presented which has also been successfully scaled to WR-10 band (75 GHz – 110 GHz). A theoretical analysis is compared to the experiments and found to agree well with the measured data.     

Generalized Bloch wave analysis for fiber and waveguide gratings

We have developed a generalized Bloch wave approach for the analysis of aperiodic gratings. This method yields both a macroscopic (i.e., reflection or transmission coefficient) as well as a microscopic (i.e., dispersion diagram and microstructure of the propagating internal field) characterization of fiber and waveguide aperiodic gratings     

A broadband Ka-band microstrip circulator for integrated millimeter wave systems

A Ka-band microstrip circulator, using ferrite with 4π M=5000 G, have been developed. By optimizing the circulator configuration, broadband n=2 Chebyshev response performance are obtained over 7 GHz bandwidth. The circulator have isolation of greater than 15 dB, and insertion loss of less than 1.0 dB.