An ultra-low loss millimeter-wave solid state switch technology based on the metal - insulator - transition of vanadium dioxide

A new ultra-low-loss and broad band millimeter wave switch technology based on the reversible metal / insulator phase transition of vanadium dioxide has been developed. We report having fabricated series configured, single-pole single-throw (SPST) switches having measured S-parameters from DC to 110 GHz. The on-state insertion loss is 0.2 dB and off-state isolation is 21 dB at 50 GHz. The resulting impedance contrast ratio, Z_OFF/Z_ON, is greater than 500:1 at 50GHz (i.e. cut-off frequency f_c ~ 40 THz). As a demonstration of the technology´s utility, we also present the results of a 2-bit real time delay phase shifter incorporating a pair of VO₂ SP4T switches. This switch technology´s high impedance contrast ratio combined with its compactness, ease of integration, and low voltage operation make it an enabler of previously unachievable high-performance millimeter wave FPGAs.