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

Abstract

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 0.15um GaAs pHEMT process and measured insertion loss less than 2.0dB and isolation more than 63dB in the frequency range of 3GHz ~ 4GHz. Output 3rd order interceptpoint above 32dBm has been recorded and the value is very high even though the unit pHEMT has gate width of 0.2mm and only four pHEMT are used in the MMIC.

Análisis de desempeño de conmutadores de microondas tipo serie-paralelo y TEE de diferentes materiales semiconductores para comunicaciones Satelitales

“…Before the 1990´s, switches on the base of p-i-n diodes had been favorites instead of FET switching devices [1]. Currently FET devices are still been developed due to their outstanding features; in the same way, phase shifter devices are often designed with p-i-n diodes which are implemented with antenna arrays for terrestrial and satellite applications.…”

“…Microwave p-i-n diode switches are characterized by low insertion loss, high power handling, high isolation switching and better microwave signal responses compared to the one using conventional diodes [1]. In practice it is usually difficult to achieve more than 40 dB isolation using a single silicon p-i-n diode, either in shunt or series, at microwave frequencies and there are proposals to use other semiconductor materials [3].…”