A novel 100 MHz-40 GHz RF termination with bias network for optical systems

A novel wide-band DC-blocked MMIC RF termination with biasing network is presented. It provides return loss better than 18 dB from 100 MHz to 40 GHz. The main advantage of the design is that the DC blocking capacitor is placed directly on top of a wide grounding Si pedestal, thanks to M/A-COM's HMIC technology, reducing the ground inductance. At the RF side of the circuit, two 100-Ohm nichrome resistors have been put in parallel giving 50 Ohm. A small stub between the 100-Ohm resistors compensates for the inductance giving a very good match up to 40 GHz, Bond-wire pads have been designed on the chip and also on the host PCB to match the inductance of double wire-bond at the RF port.