A 24GHz SiGe Double-Pole Single-Throw Switch (DPST) with 30dB Gain Control for Multi-Channel Receiver Integrated Circuits

An active Double-Pole Single-Throw (DPST) Switch operating at 24GHz is described that incorporates a voltage variable Attenuator to reduce the signal power level at the switch output terminals. The switch is fabricated in a 0.5um SiGe Bipolar process as an integral component in a Dual-Channel downconverter for UWB applications. The switch has a 3dB Gain bandwidth of over 6GHz, with a nominal Gain (Selected Input to Output) of 2dB. The channel isolation is measured (on-chip) to be greater than 35dB. The switch circuit consumes 25mA from a +5V supply and occupies an area of 0.36mm². The Attenuator allows for approximately 30dB of small-signal Gain control of the downconverter with a control voltage range of 0.5V to 3.5V.