Multiple-device and multiple-resonator low phase-noise and microwave oscillators.

Abstract

There have been increasing demands for low phase-noise and low-cost microwave frequency sources due to the rapidly growing market for wireless communication systems in the recent years. This thesis demonstrates novel multiple-device and multiple-resonator low phase-noise microwave oscillators with a potential to address the phase-noise requirements of modern communication systems. The first proposed design methodology is based on high-order resonant circuits. By properly connecting multiple resonators and optimizing coupling relations between those resonators, high-order resonant circuits can be designed to produce higher oscillator Qs compared to the conventional single resonators. This work proposes two new high-order resonant circuits based on the extended resonance technique and multiple-pole filters. The extended-resonance multiple-device oscillator is capable of improving the phase noise as a result of high oscillator Q from cascading of multiple resonant circuits as well as power combining. In multiple-pole elliptic-filter oscillators, high oscillator Qs can be achieved by utilizing group delay peaks formed at the passband edges of the filters. A SiGe HBT extended-resonance oscillator and a SiGe HBT four-pole elliptic-filter oscillator are demonstrated with phase noises of -138 dBc/Hz and -140 dBc/Hz at 1 MHz offset frequency, respectively. The 1/<italic>f</italic> noise upconversion in push-push and triple-push oscillators has also been studied. Because the 1/<italic>f</italic> noise upconversion is strongly dependent on the harmonic contents of waveforms, it should be carefully treated in push-push and triple-push oscillators that utilize harmonic components as output signals. The low phase-noise design requirements for minimizing 1/<italic>f</italic> noise upconversion in such oscillators are presented and the experimental demonstration at C band using MESFET oscillators shows 12-15 dB phase-noise improvement in 1/<italic>f</italic><super> 3</super> phase noise region.