The development of a high power SP4T RF switch in GaNHFET technology

The development of a high power, single-pole four throw (SP4T) hybrid switch using AlGaN/GaN heterostructure field effect transistors (HFETs) on Si substrate is reported for the first time for applications up to 1.5 GHz. The off-state capacitance (C-off) of a single-gate GaN based HFET is 250 fF and the on-state resistance (R-on) is 4.1 Omega at a gate length of 0.7 mu m and a width of 1 mm. The hybrid SP4T switch with a size of 4 x 4 mm 2 was implemented for system applications of three transmit paths and a receiver, of which each was configured with a series-shunt self-biased configuration. The switch has achieved an insertion loss of 1.4 dB with power handling of P-0.1dB =43 dBm at the transmitter paths and an optimized isolation of better than 25 dB at the receiver path at 1.5 GHz. In addition, a high voltage switch driver using the GaN HFET technology was designed with an input control voltage of 0/4 V to provide an output voltage of 0/26 V. This development provides a baseline design for our next generation monolithic microwave integrated circuit switches in GaN technology.