SPIRAL SCANNINGS IN LONGWAVE HOLOGRAPHY Jacob Politch* Abstract In longwave holography, the detection of the incident object wavefronts in the recording plane is accomplished by means of an array of detectors, or by a single scanning detector. It is shown that the retrived image is a function also of the Fourier transform of the spatial location of the detecting elements in the recording p

PROBLEMS CONCERNING HOLOGRAPHIC IMAGING AT MICROWAVE FREQUENCIES K. Magura * ABSTRACT This paper shows the results of holographic imaging experiments at the 35 GHz band. The hologram was reduced by an inserted lens and the images were reconstructed by computer. The effects of changes in both, the hologram-structure, i. e. hologramsize and sampling, and in the measured amplitude and phase val

COMPREHENSIVE MEASUREMENT OF APERTURE FIELDS, NEAR-FIELDS AND FAR-FIELDS OF A LARGE REFLECTOR ANTENNA FROM A MICROWAVEHOLOGRAM. J.C. BENNETT,A.P. ANDERSON, .A. McINNES, A.J.T. P WHITAKER ABSTRACT holographic technique is used to obtain quantitative data on the amplitude and phase of the principal and cross-polarised fields in the aperture of a large reflector antenna. The hologram formati

CIRCUIT LOSS CHARACTERISATION WITH AN IMPATT DIODE R.C. Tozer*, R. Charlton + and G.S. Hobson* ABSTRACT A convenient technique is described to measure the internal circuit loss, the load conductance and equivalent circuit susceptances of an IMPATT oscillator. The diode is biased just below its breakdown voltage and is used as a resonant reflection absorber. From these frequency depend

A Ka BAND AVALANCHE DIODE UP-CONVERTER by J.L. VATERKOWSKI, E. CONSTANT, Y. DRUELLE ABSTRACT: Recent experimental and theoretical results on a silicon avalanche diode up-converter are reported. A simplified theoretical analysis is developed in order to design the semiconductor device. Based upon the somewhat ideaLized Read model, this theory explains the main parametric effect used for fr

EFFECTS OF TUNNELING ON HIGH EFFICIENCY IMPATT AVALANCHE DIODES by M. CHIVE, E. CONSTANT, J. PRIBETICH, M. LEFEBVRE ABSTRACT: We study theoretically and experimentally the effect of a tunnel injection on high efficiency IMPATT avalanche diodes characterized by high low or low high low doping profile. Taking into account effects of tunneling some characteristics usually observed of such high

MILLIMETER WAVE OSCILLATIONS FROM TUNNETT DIODES Jun-ichi Nishizawa, Tadahiro Ohmi and Toshi-aki Sakai* Space and time dispersions of carrier distribution included in an avalanche build up process are discussed in Si and GaAs, especially concentrating on exchange frequency from an avalanche to a tunneling in a carrier inj ection mechanism in transit time diodes. GaAs multilayer structure has b

AN IMPROVED TRAPATT PULSE GENERATOR WITH APPLICATIONS S.C. Cripps * and J.E. Carroll * ABSTRACT The development and application of a gigahertz repetition rate pulse generator using the anti-parallel Trapatt circuit is described. The pulse generator produces 100 psec risetime pulses at 1 GHz repetition rates with over 200 volts amplitude into a 50 ohm load or open circuit and up to 4 amps in

A 12 VOLT X-BAND AVALANCHE DIODE *B. CULSHAW and*R.A. GIBLIN Avalanche diodes are becoming established as rf power sources in the microwave spectrum from X-band upwards. The conventional device does suffer from some practical disadvantagess of which the most notable are the dissipation of, typically, 10 Watts of dc power as heat from a very small device and the requirement for high bias voltag