Analysis and Design of Silicon Bipolar Distributed Oscillators

A. Hajimiri and H. Wu

A systematic approach to design of silicon bipolar distributed oscillators and VCOs is presented. The operation of distributed oscillators is analyzed and the general condition for oscillation is derived, resulting in analytical expressions for the frequency and amplitude of distributed oscillators. Special attention is paid to transmission line modeling that largely determines the performance of distributed oscillators. A distributed VCO operating at 12GHz dissipating 13mW of power is demonstrated. The VCO has a tuning range of 26% with a phase noise of -104dBc/Hz at 1MHz offset from the carrier. A second design shows a 17GHz bipolar distributed oscillator, which dissipates 9mW of power.