A simple design technique for the Gilbert cell in MMIC technology: Application to a DSB modulator

摘要

A theoretical analysis of the Gilbert cell has been performed in order to accomplish a simple design method which allows one to choose the width and the bias point (% of I/sub DSS/) of the MESFET transistors of the Gilbert cell. A wide band (1 to 5 GHz) double side band modulator has been designed and built using this method. It is comprised of an input differential amplifier, a Gilbert cell and an output differential amplifier and it has been implemented with the F20 0.5 /spl mu/m Process of GEC Marconi. A carrier rejection of 50 dB and a third order intermodulation rejection of 47 dB have been measured at 2 GHz. The DC power consumption of the Gilbert cell is 136 mW.