A 5 GHz pHEMT transformer-coupled VCO

A transformer-coupled technique is shown to be an area-efficient method for reducing oscillator phase noise. Higher signal amplitude and inductor Q can be achieved without breakdown. A pHEMT process was used to fabricate the 5 GHz VCO. The measured phase noise at 3 MHz offset frequency is -129 dBc/Hz. The VCO dissipates 9 mW.