Frequency Multiplication By A P-I-N Diode When Driven Into Avalanche Breakdown

Abstract

An investigation of frequency multiplication using a step-recovery diode (SRD) driven into avalanche is presented. This mode of operation, which is called the breakdown mode, consists of a reverse-biased p-n junction, SRD, or IMPATT diode driven into reverse by an ac signal source. As the diode voltage passes from reverse bias to reverse and avalanche, the state of the diode switches quickfy from a depletion-layer capacitance to an avalanche inductance; hence the production of strong harmonics. A theoretical analysis and experimental investigation of a coaxial/waveguide 2-6-GHz frequency multiplier using HP5082-0320 step-recovery diodes, [R/sub s/ = 0.75 Omega, C/sub d/(-6/sub v/) = 1.0 pF] shows that the breakdown-mode frequency multiplier has a higher conversion efficiency than the conventional multipuer. A measured conversion efficiency of 73 percent was achieved while the same circuit configuration produced 52 percent for the same diode used as a charge-storage multiplier under optimum forward-drive and tuning conditions. Also the theory developed in this paper indicates a maximum possible conversion efficiency of 80 percent for the breakdown-mode multiplier, which corresponds closely with the measured results, and a maximum theoretical efficiency for a forward driven diode of 64 percent. The performance of an FM microwave system was monitored using the multiplier as a LO in which a baseband SNR of 59 dB was recorded.