AlGaN/GaN Schottky Barrier Single-Pole Single-Throw RF Switch

This paper presents three types of single-pole single-throw RF switches utilizing AlGaN/GaN Schottky junction as distributed switching elements integrated in a coplanar waveguide structure. The switches are designed in shunt topology, which allows to achieve good high frequency performance. First type of switch is driven through RF port, while the remaining ones are driven by a separate electrode. The designs with separate driving electrode allow operation in a very broad frequency band down to DC. The third design further improves the switch performance by eliminating impedance discontinuities in the signal path. The best performance is achieved by the third design with 18 dB on-off ratio and 4.5 dB insertion loss at 50 GHz, as well as less than −14 dB reflection coefficient in the 10 MHz – 50 GHz frequency range. Observed performance improvement at high frequency indicates a good perspective for this kind of switch for higher frequencies up to the sub-terahertz band.