A high temperature VCO for extreme environment wireless applications

In this paper, a 60 MHz voltage controlled oscillator based on a custom-built silicon carbide (SiC) junction field effect transistor (JFET) is proposed. This SiC VCO is capable of high temperature operation up to 450 °C. A prototype is fabricated through low temperature co-fire (LTCC) process and successfully tested from room temperature to 450 °C, at which stable circuit operation is maintained. This SiC VCO is the fundamental building block of the wireless frequency modulation (FM) circuitry and can be integrated with high temperature sensing elements for wireless sensing in space exploration and other extreme environment applications.