11 THz figure-of-merit phase-change RF switches for reconfigurable wireless front-ends

We report on GeTe-based, phase-change RF switches in a series configuration with an embedded micro-heater for thermal switching. With heater parasitics reduced, these GeTe RF switches show on-state resistance of 0.12 ohm*mm and off-state capacitance of 0.12 pF/mm. The RF switch figure-of-merit is estimated to be 11 THz, which is about 15 times better than state-of-the-art silicon-on-insulator switches. With 50-μm-wide GeTe switches, RF insertion loss was 0.25 dB and isolation was 24 dB at 20 GHz. Harmonic powers were suppressed >90 dBc at 35 dBm, meeting wireless requirements. The GeTe switches were characterized under W-CDMA signals without spectral regrowth up to 25 dBm.