摘要

A 5 GHz transformer-feedback power oscillator with novel frequency modulation (FM) up to 10 MHz is presented in this paper. The novel FM is achieved by a CMOS transistor between transformer and ground, which is designed for varying the equivalent inductance and mutual inductance of the transformer and shows no DC connection with the oscillation circuit. The major frequency tuning is realized by the variable capacitor which is controlled by a phase lock loop. The RF VCO with 210 MHz tuning range operates in class-E mode to achieve a cost-effective transmitter, which demonstrates a high DC-to-RF conversion efficiency of 39 %. A RF power of 15.1 dBm and phase noise better than 109 dBc/Hz @ 100 kHz from the central frequency of 5.5 GHz is obtained with the biasing conditions V = 1.8 V and V = 0.65 V. The VCO also demonstrates an ultra-low voltage operation capability: with V = V = 0.6 V and DC power consumption of 9 mW, the output power is 4.5 dBm and the phase noise better than 93 dBc/Hz @ 100 kHz. The die size of the transformer-feedback power oscillator is only mm.