航空VHF通信设备电磁防护模块电路设计

Circuit Design of Electromagnetic Protection Module for Aviation VHF Communication Equipment

针对航空甚高频(Very High Frequency,VHF)通信设备,提出了一种具有低插入损耗、高限幅性能的电磁防护模块电路设计方法。在无源多级限幅器设计基础上外加直流偏置,构建了一款有源式防护模块以提高限幅能力。将定向耦合器与整流电路相结合,提出了以整流部分干扰信号代替外加直流偏置的方式,进一步优化设计了一款半有源式防护模块。对所设计的2款电磁防护模块进行实物加工与测试,结果表明,在118~136 MHz的航空VHF频段内,插入损耗均小于1.5 dB,起限电平小于6 dBm,限幅电平小于8 dBm,功率容量不小于25 dBm。相比于其他同类型防护模块,起限电平和限幅电平明显降低,能够有效提高防护能力。

A method of electromagnetic protection module circuit design with low insertion loss and high amplitude limiting performance is proposed for aviation Very High Frequency(VHF)communication equipment.Based on a passive multi-stage limiter designed with a DC bias,an active protection module is constructed to improve the limiting capability.Then,an optimized semi-active protection module is designed by combining a directional coupler with a rectifier circuit and using the rectified part of the interference signal instead of the applied DC bias.The two electromagnetic protection modules are physically fabricated and tested,and the results show that the insertion loss of the two modules is less than 1.5 dB,the starting limiting level is less than 6 dBm,the limiting level is less than 8 dBm,and the power capacity is not less than 25 dBm in the aviation VHF frequency band of 118~136 MHz.Compared with other protection modules of the same type,the starting limiting level and the limiting level are significantly lower,which can effectively improve the protection capability.