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 inorder to accomplish a simple design method which allows one to choosethe width and the bias point (% of I_DSS) of the MESFETtransistors of the Gilbert cell. A wide band (1 to 5 GHz) double sideband modulator has been designed and built using this method. It iscomprised of an input differential amplifier, a Gilbert cell and anoutput differential amplifier and it has been implemented with the F200.5 μm Process of GEC Marconi. A carrier rejection of 50 dB and athird order intermodulation rejection of 47 dB have been measured at 2GHz. The DC power consumption of the Gilbert cell is 136 mW