<title>High-harmonic gyrofrequency multiplier</title>

Abstract

ABSTRACT The design of a sixth-harmonic gyrofrequency multiplier driven by a 300 keV, 1 .7 A, prebunched axis-encircling electron beam produced by a 1 MW, 2.9 GHz gyroresonant H' accelerator is presented. A nonlinear simulation code predicts that the device, which is currently being tested, will emit 150 kW at 17.4 GHz with an efficiency of 31%. 1. INTRODUCTION The gyrofrequency multiplier is an exciting new efficient high power millimeter and submillimeter wave source. Asshown in Fig. 1, the device uses the intermediary of a rotating spiral-shaped electron beam produced by a gyroresonant rf accelerator to harmonically up-convert the frequency of a high power, low frequency microwave source. Since the interaction is at a high harmonic of the cyclotron frequency, the requisite magnetic field is reduced and the frequency ofexisting microwave and millimeter wave high power sources can be greatly increased. Our initial unoptimized proof-of-principle experiment demonstrated this harmonic conversion process with the production of 7 kW at the third-harmonicfrequency of 28 GHz with 13% efficiency.' The purpose of the current experiment is to dramatically increase the powerlevel, harmonic number and efficiency.