Multi-Throw SPNT Circuits Using Phase-Change Material RF Switches for 5G and Millimeter Wave Applications

Here we report on multiple series-only SPNT circuits that utilize non-volatile phase-change material (PCM) radio-frequency (RF) switches: a single-pole, single-throw (SPST, SP1T), a single-pole, double-throw (SPDT, SP2T), a single-pole, four-throw (SP4T), and a single-pole, nine-throw (SP9T) circuit. All circuits were measured at both 25 degrees C and 85 degrees C and showed minimal change in insertion loss and isolation with an increase in temperature. A series-only architecture was utilized for all circuits due to the excellent figure-of-merit (FOM) of the unit device (R-ON*C-OFF less than 10 fs). The SP4T demonstrates less than 0.6 dB of insertion loss from 0-20 GHz, and 1 dB of insertion loss at 40 GHz with greater than 25 dB of isolation across the entire 0-40 GHz band. The SP9T circuit also demonstrates less than 0.5 dB insertion loss from 0-20 GHz, and 1.5 dB of insertion loss at 40 GHz with greater than 28 dB of isolation across the entire 0-40 GHz band. This represents the first time PCM RF switches have been reported in a broadband high-throw count SPNT configuration.