Design of High Performance HEMT Switch for S-band MSM of Satellite Transponder

A SPST switch MMIC which used for microwave switch matrix (MSM) of communications satellite payload with multi-beam function has been designed and fabricated. New RF FET switch configuration has been devised to improve power characteristics and isolation. Input and output return losses are better than another switches reported previously for both on and off states. The MMIC chips were fabricated in 0.15 um GaAs pHEMT process and measured insertion loss less than 2.0 dB and isolation more than 63 dB in the frequency range of 3 GHz ~ 4 GHz. Output 3rd order interceptpoint above 32 dBm has been recorded and the value is very high even though the unit pHEMT has gate width of 0.2 mm and only four pHEMT are used in the MMIC.