一款航空VHF限幅器的设计与测试

Design and measurement of an avionic VHF limiter

摘要:

为提高航空甚高频(VHF)通信设备的电磁防护能力，提出了一种基于PIN二极管的限幅器。采用先进设计系统(ADS)仿真研究了不同二极管级数对限幅器插入损耗以及限幅性能的影响，设计了一款由PIN对管并联结构、集总参数定向耦合器、整流电路与匹配电路相结合的半有源式限幅器，通过将部分干扰信号转变为直流的方式，为二极管提供偏置电压，降低限幅器的限幅电平。性能测试结果表明，在118~136 MHz的频率范围内，半有源式限幅器的插入损耗小于1 dB，输入输出端口的回波损耗大于20 dB，限幅电平小于7.5 dBm，功率容量大于25 dBm，实现了低插入损耗与高限幅性能。

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.