Hardening measures for bipolar transistor against microwave-induced damage

In the present paper we study the influences of the bias voltage and the external components on the damage progress of a bipolar transistor induced by high power microwave (HPM). The mechanism is presented by analyzing the variation of device internal distribution of the temperature. The findings show that the device becomes less vulnerable to damage with the increase of bias voltage. Both the series diode at the base and the relatively low series resistance at the emitter R_e can make the burnout time of the device prolonged obviously. However, R_e will aid the damage of the device when the value is sufficiently high due to the fact that the highest hot spot shifts from the base-emitter junction to the base region. Moreover, the series resistance at the base R_b will weaken the capability of the device to withstand microwave damage.