Abstract

A compact coplanar passive MMIC mixer has been developed, realized and tested successfully as a cost effective part of an I/Q demodulator module for applications in 2.4 GHz transponder systems. Although there are no external elements required, the cold-FET mixer's size is only 1 mm2 including bias and active matching networks. Operating with 6V/15mA DC bias, required by the active matching FETs, the mixer has a maximum conversion gain of -2 dB at 9.5 dBm LO power and 100 MHz IF frequency. Intermodulation measurements show an IP3 of 6.9 dBm. The small wafer area is due to a consequent use of active elements for matching and biasing purposes.