2100 W at 425 MHz with SiC RF power BJTs

Abstract

4H-SiC RF bipolar junction transistors (BJTs) have been designed and tested at 425 MHz. Twenty four cells representing approximately 24 inches of emitter periphery were packaged and tested at 425 MHz in common emitter, Class C mode with a 75 V power supply voltage. The pulse width was 2 mus and duty cycle 1%. The total output power was measured to be 2100 W with a power gain of 6.3 dB, collector efficiency of 45% and power added efficiency of 35%. This is the first time, SiC BJTs have been used to produce an output power in excess of 2 kW at 425 MHz. Although the gain and PAE are not very high, the individual cells are capable of producing 50 W with a gain of 9.3 dB and 51% collector efficiency (Agarwal, 2002). By further optimization of the device design, cell layout, the input and output match, and by increasing the power supply voltage to 120 V, it is expected that the output power, gain and efficiency can be further improved