DescriptionThis thesis proposes a design for a low-power downconverter and demodulator, formed by a voltage controlled oscillator and mixer to create a Vance demodulator. This system is intended to operate in the MedRadio frequency band (401-406 MHz). The MedRadio band is intended by the FCC for ultra low-power radios used for medical applications to carry non-voice data. A combination of gm/ID design methods and MATLAB scripting have been used to efficiently calculate the size of transistors within the VCO circuit. Using the transconductance and bias current ratio (gm/ID) value as a primary design variable efficient operation is ensured with this a geometry independent process. The MATLAB script, combined with simulated device information, allows for automation of device sizing, increasing accuracy of results over conventional square-law hand-calculations. The result of this work and design method is a 26 microwatt direct down-conversion DPSK demodulator in the MedRadio, designed in an 8RF CMOS process. The circuit utilizes a two-stage VCO design directly coupled to a passive ring mixer. With biasing circuits it requires an active die area of 49 um x 39 um. The circuit is designed to operate from a 1 V supply and achieves a post-extracted simulated phase noise of -118 dBc/Hz when injection locked. The passive mixer has been designed to achieve a conversion gain of -18.4 dB.