Abstract: Our laboratory has developed a two-dimensional semiconductor device simulator to analyze the burnout mechanism of semiconductor devices with high power microwave injection. In this paper, the simulator is further developed to include the SPICE model of microstrip lines irradiated by an incident wave. The developed simulator can be used to analyze the high power microwave irradiation effects on PCB circuits with semiconductor devices. With the developed simulator, a practical PCB circuit including a low noise amplifier (LNA) is simulated in two cases, i. e. the PCB circuit is directly irradiated by an uniform plane wave and the PCB circuit is placed in a shielding cavity with a slot during irradiated. For the first case, different incident modes of plane wave are simulated and the burnout t