The design of a high-frequency voltage-controlled oscillator in BiCMOS using on-chip inductors

The design of a monolithic LC voltage-controlled oscillator implemented in silicon BiC-MOS technology suitable for applications such as mobile radio is presented in this thesis. The object of this work is the design of a VCO capable of GHz operating frequencies and low phase noise. A significant portion of this work is directed toward the development of models which facilitate the prediction of oscillator performance and phase noise characteristics. The relationship between quality factor, tuning range, and phase noise are investigated. The circuit is based on a Gilbert cell structure which utilizes two LC tuned circuits with different resonant frequencies. Inductors are implemented as square planar spirals on a layer of silicon oxide. An experimental version of the circuit realized a tuning range of 37 MHz with a center frequency of 1.5 GHz. The results of the simulation of oscillator performance and phase noise are contrasted to the measured characteristics of the fabricated circuit.