Reconfigurable inline phase-change switches for broadband applications

Improvements to the GeTe inline phase-change switch (IPCS) technology have resulted in a 10× increase in the figure-of-merit (FOM) for radio-frequency (RF) switches. An ON-state resistance of 0.9 Ω (0.027 Ω·mm) with an OFF-state capacitance and resistance of 14.1 fF and 30 kΩ, respectively, were measured. This results in a switch cutoff frequency (F
_co
) of 12.5 THz, with an OFF/ON resistance ratio of 10,000:1. Passive RF circuits have been built with these switches to compare their frequency performance to state-of-the-art technologies, as well as to demonstrate fine-grain reconfigurability in RF circuits. Further analysis of 8-port omni-directional IPCS switches used in a reconfigurable transceiver demonstrates less than 2dB degradation in gain and 1dB in noise figure when reconfiguring a single chip for 4 different receiver chain frequencies (S-band, X-band, Iridium, and CDL-Ku), demonstrating the feasibility of IPCS devices for low-power, broadband reconfigurable RF systems.