Fully Depleted SOI RF Switch with Dynamic Biasing

RF switches based on fully depleted (FD) SOI technology are reported for the first time. In a novel biasing circuit, the conventional bias resistor at the gate of the series MOSFET switch is replaced with another FET, which functions as a variable resistor and presents different resistance optimal for the on-and off-state. The low parasitic capacitance of FDSOI improved the switch performance and the dynamic biasing further increased the saturated power. At 5 GHz, a single-pole double-throw (SPDT) switch with integrated control circuits has 0.75-dB of insertion loss and 39-dB of isolation. The 1-dB-compression power of this dynamically biased SPDT switch approaches 2 W at 5 GHz.