Low Phase Noise X/Ku-Band VCO

A balanced, thin-film VCO utilizing silicon bipolar transistors and hyper-abrupt varactor diodes has yielded 40% tuning bandwidth while demonstrating excellent frequency stability. Key features of this design are: High RF output power, linear tuning characteristics, excellent sub-harmonic rejection, and low single sideband phase noise. At an operating frequency of 11.5 GHz, single sideband phase noise of -104 dBc/Hz at 100 KHz offset has been obtained. An X-band VCO subsystem designed for missile LO applications utilizing the developed oscillator is also presented.