A New Design Approach for Low Phase-Noise Reflection-Type MMIC Oscillators

摘要

In this paped optimization of the loaded quality factor Q_L for reflection-type heterojunction bipolar transistor (HBT) oscillators is investigated. The main result is an optimum relation between the S-parameter phases at the three transistor ports. A new design strategy for this type of oscillator is proposed. The analysis is verilied by comparing several Ka-band monolithic-microwave integrated-circuit oscillators in GaAs HBT technology with different resonators. The measured loaded Q_L values correspond to the measured phase noise of the circuits. At an oscillation frequency of 33 GHz, an excellent phase noise of -87 dBc/Hz at 100-kHz offset frequency is achieved over the whole tuning range.