Abstract:A design method of limiter based on PIN diode is proposed in order to improve the electromagnetic protection capability of the aeronautical Very High Frequency(VHF) communication equipment. The influence of different diode stages on the insertion loss and limiting performance of the limiter are simulated and researched by Advanced Design System(ADS). Furthermore, a semi-active limiter is designed, which is composed of PIN pair parallel structure, directional coupler with lumped parameter, rectifier circuit and matching circuit. To reduce the limiting level of the limiter, a bias voltage is provided for the diode by converting part of the interference signal into DC. The measurements show that the insertion loss of the limiter is less than 1 dB, the return loss is more than 20 dB, and the limiting level is less than 7.5 dBm, the power capacity is more than 25 dBm in 118~136 MHz, which realizes the low insertion loss and high limiting performance.