A wide-band T/R switch using enhanced compact Waffle MOSFETs

A wide-band complementary metal oxide semiconductor (CMOS)transmit/receive (T/R) switch using enhanced compact waffle metal-oxide-semiconductor field-effect transistors (MOSFETs) is presented. The compact waffle layout configuration saves much active area to give a low on-resistance. Furthermore,the low drain-to-substrate capacitance (CDB) in waffle MOSFETs can help reduce high frequency substrate coupling and substrate loss for CMOS radio frequency (RF)/microwave integrated circuits (ICs). A 2-dB higher maximum stable gain/maximum available gain (MSG/MAG)and a 2-GHz higher f_max are obtained compared with those of conventional multifinger MOSFETs. The CMOST/R switch implemented in a standard 0.35-μm CMOS technology gives a low insertion loss of 1.7dB,high isolation of more than 40dB, larger than 15-dB return loss, 7-dBm P/sub 1 dB/ and 13-dBm input IP3 at 900MHz with a 3-V supply voltage. The switch maintains a wide-band performance up to 2.4GHz with only a slight deterioration.