Multiple-device single-cavity Gunn combiner for electron spin resonance spectrometer

Abstract

A multiple-device single-cavity power combiner has been designed as a microwave source for ESR spectrometers. The X-band oscillator is mechanically tuned over a range of 800 MHz. The output power exceeds 500 mW across the tuning range. Varactor tuning assures fast tuning over a range of 30 MHz. A water-cooled combiner is phase-locked with respect to a quartz oscillator and adjusted to an actual resonant frequency of the spectrometer sample cavity by an AFC unit. Using this combiner it was possible to record weak pitch signal for a modulation frequency of 80 Hz, whereas such recording using a klystron oscillator as a microwave source was unsuccessful.