An Intermediate Frequency Amplifier for High-Temperature Applications

This paper presents a two-stage small signal intermediate frequency amplifier for high-temperature communication systems. The proposed amplifier is implemented using in-house silicon carbide bipolar technology. Measurements show that the proposed amplifier can operate from room temperature up to 251 degrees C. At a center frequency of 54.6MHz, the amplifier has a gain of 22 dB at room temperature, which decreases gradually to 16 dB at 251 degrees C. Throughout the measured temperature range, it achieves an input and output return loss of less than -7 and -11 dB, respectively. The amplifier has a 1-dB output compression point of about 1.4 dBm, which remains fairly constant with temperature. Each amplifier stage is biased with a collector current of 10 mA and a base-collector voltage of 3 V. Under the aforementioned biasing, the maximum power dissipation of the amplifier is 221 mW.