车辆点火脉冲对短波电磁环境影响的数值模拟与试验研究

为评估车辆点火脉冲对短波接收站电磁环境的影响，首先分析了车辆点火原理模型，并测试了小轿车、卡车两种典型车辆的点火脉冲生成的频域噪声；其次利用基于距量法的电磁计算软件对小轿车、卡车的点火脉冲等效天线与10 m单极子接收天线之间的传输效应进行了数值模拟与分析，获得传输损耗波动曲线。最后通过3辆汽车点火实测对乡村短波接收站的电磁环境影响进行了对比分析。仿真与实测结果表明:卡车点火脉冲辐射功率高于小轿车辐射功率14 dB；车辆点火脉冲等效天线相对于10 m单极子接收天线，在7.5 MHz传输损耗最小，相距30，100 m时传输损耗分别为24，32.2 dB；试验中，在30 m距离处，3辆小汽车点火脉冲对短波电磁环境的影响为抬高了低频段底噪1～2 dB，当距离增加到100 m以上时，已无明显影响。

Electromagnetic environment effects of vehicle ignition pulses on shortwave radio receivers

To evaluate Electromagnetic Environment Effects (E3) of the vehicle ignition pulses on High Frequency Receiving Station (HFRS), a model of the vehicle ignition circuit has been analyzed, and frequency spectrums of the noises induced by a car and a truck at the moment of their engine being ignited were measured. Using the method-of-moments-based electromagnetic simulation tool, we have modeled the ignition-equivalent antennas by a car and a truck respectively and obtained their transmission loss fluctuation curves in the transmission path to a 10 m long monopole receiving antenna. In comparison, E3 of the engine ignition by two cars and a truck on HFRS in the countryside was measured. Simulation shows that the least transmission loss from the car and truck to the 10 m monopole antenna located 30 and 100 m away occurs at 7.5 MHz, which is 24 dB and 32.2 dB respectively. This measurement indicates that the emitting signal induced by the engine ignition of the truck is 14 dB higher than that of the car. In the distance of 30 m from the vehicle, the noise floor in the low frequency band is raised 1?2 dB. When the distance is increased to 100 m, the effect can be neglected.