A low phase noise microstrip push-push oscillator with third harmonic output

Abstract

The results of the low noise microstrip oscillator design with 11 GHz output are presented in the paper. The oscillator is stabilized by the microstrip resonator and performed in the push-push circuit. In contrast to traditional even harmonics output, the third harmonic output is used, which is obtained by means of proposed 0-180° combiner unit at the oscillator‟s output. The use of third harmonic output signal made it possible to suppress even harmonics in the oscillator branches, which contributed to the phase noise reduction. Phase noise of the designed oscillator is measured to be no more than -92 dBc/Hz, -113 dBc/Hz, and -130 dBc/Hz at 10 kHz, 100 kHz, 1 MHz offsets from carrier, respectively.