DC to 20 GHz GaN SPDT Switch

GaN technology is now widely adopted for high power microwave amplifiers. The high breakdown voltage of the transistors is key to their ability to provide high power amplification and it also means they can be used to realise very high linearity RF and microwave switches. This case study describes the design and implementation of a DC to 20 GHz Single Pole Double Throw (SPDT) GaN MMIC switch. It offers an IP3 of 62 dBm with an insertion loss of just 0.75 dB at 1 GHz rising to 1.3dB at 20GHz. Isolation is over 45dB and the die size is just 1.6mm squared.