Nonlinear design of low phase noise oscillator based on load line analysis

A novel approach to the design of a low phase noise oscillator is presented, which enables one to optimize the phase noise and the oscillation power simultaneously. Through a load line analysis of a transistor without feedback, the oscillation power and the base-band (1/f) noise up-conversion factor are investigated and predicted. In the implementation of an embedding feedback network, a generalized formulae considering the quality factors of the embedding feedback elements are newly introduced. The proposed approach is applied to the design of an engineering model voltage controlled oscillator for a satellite transponder. The phase noise characteristics of the manufactured VCO exhibit -114dBc/Hz @10 kHz offset and -133 dBc/Hz @100 kHz offset at 1748 MHz.