Silicon-on-sapphire MOSFET transmit/receive switch for L and S band transceiver applications

A single-pole double-throw transmit/receive switch has been fabricated with MOSFETs in silicon-on-sapphire technology. The switch has an insertion loss of 1.7 dB and an isolation of >30 dB at 2.4 GHz. The switch was targeted for 2.4 GHz operation, but is broadband with only a 2.0 dB insertion loss at 5 GHz. The same switch was also fabricated on SIMOX as a comparison. Owing to capacitive losses to the substrate, the SIMOX switch had a much higher insertion loss: 4.9 dB at 2.4 GHz and 6.2 dB at 5 GHz.