26 GHz coplanar SiGe MMICs

First results on coplanar MMICs with SiGe HBTs are presented. The circuits are fabricated on high-resistivity Si substrates using a double-mesa HBT process. In the Ka-band, an oscillator output power of 1 dBm and 4.4 dB gain for a one-stage amplifier are achieved. This demonstrates the potential of SiGe transistors for applications in the higher microwave range.