A SiC BJT-Based Negative Resistance Oscillator for High-Temperature Applications

This brief presents a 59.5 MHz negative resistance oscillator for high-temperature operation. The oscillator employs an in-house 4H-silicon carbide BJT, integrated with the required circuit passives on a low-temperature co-fired ceramic substrate. Measurements show that the oscillator operates from room temperature up to 400 °C. The oscillator delivers an output power of 11.2 dBm into a 50 Ω load at 25 °C, which decreases to 8.4 dBm at 400 °C. The oscillation frequency varies by 3.3% in the entire temperature range. The oscillator is biased with a collector current of 35 mA from a 12-V supply and has a maximum dc power consumption of 431 mW.