Optimization of NDR VCOs for Microwave Applications

摘要

In this paper we present a comparison of five proposed negative-differential resistance (NDR) voltage controlled oscillators (VCOs) for microwave applications. The VCO circuits comprise a GaAs transistor and a BJT current mirror (CM). The equation for calculating the terminal current is derived for each oscillator circuit. The comparison of VCOs is conducted by using a commonly used figure of merit (FOM). The best designed VCO is tuned in a frequency band of 1.252 to 1.595 GHz with maximum phase-noise of -142.3 dBc/Hz@100-kHz and delivers minimum 19.2 dBm of output power. Power consumption of the VCO core is 52 mW. The implemented prototype of the oscillator operates at 683.8 MHz, draws 2.1 mA from a 9 V power supply and generates low-noise low-distortion signal.