摘要:

Since 1970, InP has been developed as a material for microwave oscillators and amplifiers, with most interest to date being taken in transferred-electron devices. the physics of electron transport and of transferred-electron oscillators is reviewed; the features of greatest practical significance are the high potential oscillator efficiency set by the peak-to-valley ratio, which is approximately 3·5, of the velocity/field curve; studies of cathode-contact effects which have led to oscillator efficiencies over 20% and the observation of limited-space-charge-accumulation (l.s.a.) mode operation. Consideration is also given to other less developed InP microwave components, including transferred-electron small-signal amplifiers which have given noise measures of 8 dB at 15 GHz, and field-effect transistors for which encouraging preliminary results have been obtained.

DOI:10.1049/ij-ssed.1976.0001

出版商:IEE    

年代:1976

数据来源: IET

摘要:

The use of avalanche and transit-time effects in microwave transistor-like structures is being explored to provide increased gain and higher-frequency operation of 3-terminal semiconductor power amplifiers. The paper describes certain aspects of the avalanche-multiplication process of importance for understanding c.a.t.t. operation and for c.a.t.t. design. It is shown thatn-p-nsilicon c.a.t.t.s can be designed to operate with moderate charge multiplication without requiring a critical value of collector-base bias voltage. Space-charge effects reduce the actual multiplication at high injection levels. Avalanche-generated holes, returning to the emitter and base regions, have profound effects on the d.c. and r.f. characteristics of the c.a.t.t. These effects are qualitatively understood. Experimental results are reported on device impedances, gain and bandwidth in the 2.5–4.0 GHz region.

DOI:10.1049/ij-ssed.1976.0002

出版商:IEE    

年代:1976

数据来源: IET

摘要:

The subject of the paper is the monolithic integration of digital circuits on GaAs, a technique which is of significance for the subnanosecond range. Planar Gunn devices operated in the triggered-domain mode are used, and the technological requirements of such circuits are described. The limits of GaAs integrated circuits with regard to package density and bit rate are given. A dynamic shift register with Gunn devices for multiplexing and demultiplexing techniques in connection with p.c.m. transmission in the gigabit-per-second range is demonstrated. The technological level attainable at present is illustrated by a dynamic shift register consisting of five monolithically integrated Gunn devices. Experimental results with continuously operating circuits for a bit rate close to 2 Gbit/s are reported.

DOI:10.1049/ij-ssed.1976.0003

出版商:IEE    

年代:1976

数据来源: IET

摘要:

Siliconp+-nn+trapatt diodes have been fabricated by integral-heat-sink (t.h.s.) technology. The gradedp+njunction has been formed by two methods; by deposition and by a low energy implantation, both of which were followed by a drive-in period. Oscillator efficiencies of 55% in L-band, and 35% in X-band were recorded. R.F. peak powers of up to 15 W in X-band have been observed. J-band operation has been obtained by 2nd-harmonic extraction, giving efficiencies of 13% to 16 GHz. Low steady-state thermal impedance has enabled operation with mean powers in excess of 1 W in X-band. Diodes with improved transient thermal impedance have enabled operation to be extended beyond 5 μs pulsewidth. Coaxial amplifier circuits produced small-signal gains of 9 dB and added-power efficiencies of 25% at 9 GHz. Large-signal gains of 4 dB with 1 dB bandwidths of 500 MHz with r.f. peak powers of over 12 W have been obtained. Amplifiers have been operated with a 1 dB variation in gain over a temperature range of 50 deg C.

DOI:10.1049/ij-ssed.1976.0004

出版商:IEE    

年代:1976

数据来源: IET

摘要:

The large-signal performance of baritt and dovett (double-velocity transit-time) devices is analysed using an analytical model and computer simulations. The predictions agree well with each other and, in the case of baritts, with experimental results. Efficiencies of more than 25% are predicted for some dovett devices.

DOI:10.1049/ij-ssed.1976.0005

出版商:IEE    

年代:1976

数据来源: IET