An investigation of millimeter wave switches based on shunt transistors including SPDT SWITCH MMICs up to 300 GHz

This paper reports on a design study for millimeter wave single-pole multiple-throw switches, which are based on shunt transistors. For the investigation of an optimized design flow this study focuses on the three main steps of a millimeter wave switch design: identifying the optimum transistor gate width, large signal modeling of shunt transistors and the MMIC design. Based on the investigations of the optimum transistor gate width, it will be shown that insertion loss and output signal dynamic of a switch are directly correlated to the on-resistance of the utilized semiconductor technology. To prove the feasibility of this study, two RF SPDT switch MMICs, operating in the frequency range from 53 to 150 GHz and from 200 to 330 GHz, respectively, were designed and fabricated. Both switches show low insertion loss, high output signal dynamic, high yield and good agreement to the S-parameter simulations, based on the proposed shunt FET model. The proposed W-band and H-band SPDT switch MMICs achieve an insertion loss of 2 dB and 1.7 dB, respectively, and an output signal dynamic of up to 47 and 20 dB, respectively.