A dual band SiGe MMIC LNA and mixer with ground shield for WCDMA and CDMA applications

A single chip 2.7 V dual band SiGe RF front end for 2140 MHz WCDMA and 882 MHz CDMA operation has been implemented by a standard SiGe bipolar process with an f/sub max/ of 50 GHz utilizing a ground shield layer structure upon low resistive silicon substrate. The LNAs are gain controllable single stage amplifiers with high linear characteristics. The mixer circuits are double balanced Gilbert (1997) type micro-mixers with differential IF buffer amplifiers.