Abstract

This paper presents a simple design technique for differential amplifiers working at frequencies above few GHz, that allows the application of well-known low frequency techniques to microwave circuitry. It is based on the parametrization of the characteristic functions of a differential pair -CMRR and differential gains - in terms of only three design variables: drain resistor Rd gate width Wl and normalized bias current i=Id/Idss A 0.5-6 GHz power divider providing both in-phase power division and gain has been designed using the proposed technique. An amplitude balance <0.2 dB and a phase balance <3° have been measured. The chip has been designed using the 0.5 um, F20 process of GEC-Marconi.