Low Temperature Superconducting RF MEMS Devices

A dc contact and a capacitive contact niobium-based superconducting radio frequency (RF) microelectro-mechanical systems switches are presented for the first time. The switches are amenable to integration with superconducting-micro-electronics technology. A comparison of the RF performance of the switches at room and cryogenic temperatures indicate a significant improvement in the insertion loss of the switch when niobium is superconducting. A niobium-based dc contact single-port-double-throw switch is designed, fabricated, and tested. Two types of switched capacitor banks are also designed each implementing one of the two types of the introduced switches. The measured results of the capacitor bank with capacitive contact switches show variation of the capacitance value from 0.4 to 0.94 pF. The measured results of the capacitor bank with dc contact switches show variation of the capacitance value from 0.2 to 1 pF at 4 K.