A mm-wave transformer based transmit/receive switch in 90nm CMOS technology

A new lumped-element switch topology has been proposed. The switch only incorporates shunt transistors, which makes it more realizable at mm-wave frequencies. Parasitic capacitances are in shunt with the signal path and are resonated out with the effective inductance of a transformer. A 50 GHz transformer based single pole double throw (SPDT) shunt switch was designed and fabricated in 90nm digital CMOS process. It has a minimum insertion loss of 3.4dB at 50GHz from the single pole to the ON-thru port and a leakage of 19dB from the single pole to the OFF-thru port. The isolation is 13.7dB between the two thru ports. Return loss for the single pole and ON-thru ports is better than −10dB. Large signal measurements verify that the switch is capable of handling +14dBm of input power at its 1dB compression point. The fabricated SPDT switch has a small active area of 60µm×60µm.