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°C and 85°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 (RON*COFF 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.