A low-power dual-band oscillator based on band-limited negative resistance

This paper presents a 2.1/3.9 GHz oscillator based on switching the negative resistance bandwidth of a capacitively degenerated common collector stage, while using a high order resonance tank. Multi-band oscillators have traditionally been implemented by reconfiguring the oscillator tank. In this paper, we employ a fixed high order resonator, and move the bandswitching mechanism from the tank to the loss compensation network (i.e. negative resistance network), thus maintaining the high quality factor of the tank at multiple oscillation frequencies. The proposed oscillator is implemented in a 30GHz fT GaAs process with VBE=1.3V. The measured phase noise for both bands is −136dBc/Hz at 1MHz with a power consumption of 5.1mW, and a FOM of −195.39dBc/Hz and −200.72dBc/Hz for 2.1 and 3.9GHz respectively.