UHF to Ka band upconverter

Journal of Infrared, Millimeter, and Terahertz Waves - A balanced upconverter curcuit has been developed in planar transmission line configuration using NEC GaAs beam lead Schottky barrier diodes....     

Uhf to Ka band upconverter

A balanced upconverter circuit has been developed in planar transmission line configuration using NEC GaAs beam lead Schottky barrier diodes. RF power output of +1.6 dBm SSB is obtained at Ka-band when up converter is driven by +17 dBm IF and +20 dBm LO signal.     

Q band microwave-biased photoconductive detector

A microwave-biased photoconductive detector operating in a cavity resonant at 36 GHz is described. The potential advantages of working at this high microwave frequency are outlined, and the microwave system is described. A photocurrent gain of 55 is reported, and measurements show that this value is degraded by about 25% at optical-modulation frequencies approaching 1 MHz.     

Q band GaAs Schottky-barrier IMPATT

Microwave power at Q band is reported from GaAs Schottky-barrier avalanche diodes. A nickel-contacted epitaxial GaAs structure in a flipped mesa configuration was used. In a Q band waveguide cavity, 0.5 W was obtained at 26.7 GHz using a pulsed voltage source.     

Gunn-diode operation at Q band frequencies

Operation of Gunn oscillators at Q band frequencies is reported. Useful c.w. output powers were obtained and a practical resonant circuit was examined.     

Microwave-package measurements at the Q band

The elements of the ? equivalent circuit of S4 microwave packages with a range of bond-lead geometries have been measured at the Q band.     

Fractional delay sigma-delta upconverter

A new architecture for IF to RF conversion is presented. The architecture is based on a tunable continuous-time bandpass /spl Sigma//spl Delta/ modulator with fractional delay in combination with a Manchester coder and decoder. The suitability of the proposed architecture is discussed in the context of a software-defined radio. Mixed-signal behavioural simulations confirm the validity of the concept.     

对极鳍线在空间功率合成器中的应用

介绍了一种新型的宽频带波导-微带渐变对极鳍线转换结构的设计方法及其在扩展同轴空间功率合成器中的 应用。该对极鳍线过渡形式采用一次函数、三角函数与指数函数相结合的新型复合函数曲线方程来代替传统的鳍线渐 变线函数方程，并利用对极鳍线自身结构的优化调整，就可以对频带内谐振频率产生抑制作用，不需外加任何谐振抑 制结构或金属孤岛，减少了设计和制造的复杂性。将其应用于6-18GHz 同轴空间功率合成器并经实际测试表明，合成 器在全频段内具有较低的插入损耗和回波损耗，从而证明了该设计方法的可行性。     

Q and V band power InGaAs MESFETs

Excellent power performance at 44 and 60 GHz demonstrated by 0.25 mu m gate InGaAs MESFETs is reported. From small-signal S-parameter measurements, these devices typically have extrinsic f/sub t/ greater than 100 GHz. At 1 dB compression point, a 150 mu m wide MESFET shows a power added efficiency of 33% with an output power of 60.8 mW (0.43 W/mm) at 44 GHz. For 200 mu m wide devices, the power added efficiency was measured to be 19% with an output power of 82 mW (0.41 W/mm) at 60 GHz. These results indicate that InGaAs MESFETs are viable millimetre-wave power devices.<>     

Q band interferometer for high temperature measurements

A Q band interferometer for determining the complex permittivity of solids and liquids between 20°C and 1300°C has been developed. The Roberts and Von Hippel standing-wave method was used. The technique involves the utilization of a computer-assisted digital voltmeter for data acquisition and treatment. Results for a 67SiO₂?33Na₂O within the temperature range 20–400°C and in the liqid state (950°C) are presented.     

The Ultra-Bandwidth Finline Coupler

The "finline coupler" is a recently developed microwave circuit element with which it has been possible to assemble hybrid junctions, directional couplers, and polarization-selective couplers capable of operating over bandwidths of at least three-to-one in frequency. Constructional details and experimental results are given.     

Millimetric Nonreciprocal Coupled-Slot Finline Components

Promising preliminary results are presented for isolators and a four-port circulator in novel finline structures in the frequency range 26.5-40.0 GHz. The basic configuration is a ferrite-loaded coupled-slot finline with the ferrite magnetized parallel with the direction of propagation. The nonreciprocal effects of the odd mode propagating alone and of the odd and even modes propagating are described. All structures exhibit a 20-dB isolation bandwidth greater than 3.6 GHz. It is suggested that such structures would also be suitable for higher frequencies.     

GaAs FET upconverter for TV tuner

The critical part of a broad-band TV tuner, i.e., the upcon-verter was fabricated with simple GaAs IC's. The results obtained were: 1) "Pure" frequency spectrum due to double balanced mixer configuration. 2) Constant conversion gain of 12 ± 2 dB over the entire TV band (50-900 MHz). 3) Good linearity for large signals: Suppression of third-order intermodulation >40 dB for typical bias. 4) Low noise figure (typically 8 dB). These data demonstrate the feasibility of a monolithically integrated single-range TV tuner on GaAs.     

鳍线阶梯不连续的散射特性

本文应用谱域法和谐振腔法分析了鳍线阶梯不连续性,给出了等效阶梯电纳的计算公式。这种方法具有计算简单、速度快的特点,便于CAD应用。     

Ka/Q band GaAs IMPATT amplifier technology

GaAs IMPATT diodes are capable of generating 2 to 3 W simultaneously with 18–22% efficiency in the 33 GHz to 46 GHz frequency band. The design of the amplifier circuits which utilize these devices is discussed. The circuit design is based on a 3-step closed form algorithm. The first step is a passive circuit characterization with an automatic network analyzer. In the second step, a computer is used to generate diode device lines. The third step is load line synthesis for predictable operation. The resulting performance is described. 2 W over a 2GHz bandwidth was achieved simultaneously with a minimum gain of 12 dB.     

Millimetre-wave electro-optical upconverter for wireless digitalcommunications

A millimetre-wave optical upconverter using a semiconductor laser diode and high-speed external optical modulator is described. Upconversion and transmission of 16-QAM and 64-QAM digital subcarriers over a 38 GHz optical fibre-wireless link are demonstrated     

Recent Advances in Finline Circuits

Detailed studies of transmission properties of the finline coupler have revealed existence of certain phenomena which adversely affect the transmission characteristics. A discussion of the origin and successful elimination of such effects is described. New applications for the finline coupler have been found in the design of hybrid junctions, twists and bends in multimode waveguide, and other polarization selective devices. The paper concludes with a presentation of theoretical and experimental results in the application of finline techniques to low-pass microwave filters.     

毫米波鳍线结构的数值研究

本文采用边界元法对鳍线结构进行了混合模分析,该方法具有推导简单,计算量小,处理问题灵活等特点,它可对各种鳍线进行研究,其中包含鳍的厚度,波导模深度,不对称结构及具有多种介质等。文中对几个典型的例子进行了计算,得到的数据均与其它方法的结果相吻合。     

Transverse Resonance Analysis Discontinuities of Finline

A method of analysis is proposed for characterizing finline discontinuities. Two conducting or magnetic planes are inserted at some distances away from the discontinuity so as to obtain a closed resonant structure. A transverse resonance technique is then used to compute the resonant frequencies and, from these, the equivalent circuit parameters of the discontinuity. In the particular case when the discontinuity is removed, the method can be used to characterize uniform finlines.