A 60-MHz Silicon Carbide Voltage-Controlled Oscillator for Extreme Temperature Applications

In this brief, a custom-built silicon carbide (SiC) junction field-effect transistor (JFET) is characterized from room temperature to 52°C, and a 60 MHz voltage-controlled oscillator (VCO) based on this SiC JFET is designed and fabricated through low temperature co-fired ceramic (LTCC) process. The test results of the VCO prototype demonstrate that the proposed SiC JFET VCO is capable of operating from 25 °C to 500 °C. RF signal of 50dB above the noise floor is generated, and the tuning gain of 9.22 kHz/V is achieved at 500 °C. The proposed SiC JFET VCO can serve as the fundamental building block for wireless sensing or data communication in extreme temperature industrial and space applications.