Accession Number : AD0865744

Title :   Fundamental Frequency of Oscillation in LSA Circuits.

Descriptive Note : Technical rept. Sep 68-Aug 69,

Corporate Author : CORNELL UNIV ITHACA NY SCHOOL OF ELECTRICAL ENGINEERING

Personal Author(s) : Foulds, Kenneth W. H.

Report Date : FEB 1970

Pagination or Media Count : 62

Abstract : The report traces out the development of the low frequency equivalent circuit of the diode-on-a-post type waveguide LSA oscillator and shows that circuit conditions exist for the low frequency oscillations. The input impedance presented to a diode mounted in a rigid waveguide combined with a three-quarter wavelength choke is analyzed in some detail and it is shown that this structure also can support a low frequency oscillation. Experiments in a coaxial cavity have shown the existence of two modes of oscillation. In the higher frequency mode, thought to be LSA, the effective diode capacitance was 1.6 times the cold capacitance, and N/f for the fundamental frequency of oscillation was less than 200,000 sec/cc. A description is given of a resonant waveguide iris structure combined with a ridge waveguide which produces X band output as only the second harmonic frequency. Preliminary experiments have given 13 watts at 4% efficiency at X band and over 50 watts at 10% at the fundamental frequency. (Author)

Descriptors :   (*MICROWAVE OSCILLATORS, SEMICONDUCTOR DIODES), ELECTROMAGNETIC COMPATIBILITY, RESONANT FREQUENCY, WAVEGUIDES, SPACE CHARGE, X BAND, CAPACITANCE.

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE