SPDT switch MMIC using E/D-mode GaAs JFETs for personal communications

The design and performance of a monolithic GaAs SPDT switch applicable to a time division duplexer for personal communications are described. For a switch IC used in a portable handset for personal communications, 3-V battery operation is mandatory. In order to meet this requirement, the IC was realized by utilizing four depletion-mode switch JFETs (junction field effect transistors) with superior pinch-off characteristics, and an enhancement-mode control JFET. An excellent small insertion loss of less than 0.7 dB and a high isolation of 30 dB have been achieved at 1.9 GHz.<>