频率步进连续波雷达电磁辐射2阶互调虚警干扰效应规律

为提高雷达装备电磁防护能力，研究了电磁辐射对典型雷达造成的2阶互调虚警干扰效应。以频率步进连续波雷达为研究对象，结合理论分析与效应试验的方法，分析了虚警目标的电平变化规律、波形特征以及出现位置，并给出了敏感频偏(频段)与敏感频差的测试方法。结果表明：双频电磁辐射在接收机下变频的过程中会产生2阶互调信号，该信号在适当条件下会使受试雷达产生一个位置固定的“尖峰型”虚警目标，其位置可通过计算得到；当双频干扰任一分量或两分量同比例增强时，2阶互调虚警电平初期近似线性上升，而后增速趋缓直至电平达到最大值，随后电平逐渐下降；2阶互调虚警电平最大值可远高于单频干扰情形；受试雷达2阶互调虚警干扰敏感频偏约为(f₀-180 MHz)～(f₀+160 MHz),敏感频差不高于2.70 MHz。

Laws of Second-order Intermodulation FalseAlarm Interference Effect for Stepped-Frequency Continuous Wave Radar underElectromagnetic Radiation

In order to improve the electromagnetic protection ability of radars, second-order intermodulation false alarm interference effect caused by electromagnetic radiation on ordinary radars is studied. And a stepped-frequency continuous wave radar is studied. Using theoretical analysis and conducting tests, the level change law, waveform characteristics and location law for false alarm targets are studied, and the test methods for sensitive frequency offset (frequency band) and sensitive frequency difference are released. The results show that the dual frequency electromagnetic radiation can produce a second-order intermodulation signal during the down conversion of the receiver, which can make the tested radar produce a “spike” false alarm target with a fixed and calculable position under appropriate conditions. With any component or two components of dual frequency interference increase in the same proportion, the second-order intermodulation false alarm level increases linearly at first and then slowly increases until it reaches its maximum, and then decreases slowly. False alarms caused by the second-order intermodulation can be much higher than those caused by single frequency interference. The sensitivity frequency band of the tested radar is about (f₀-180 MHz)~(f₀+160 MHz), and the sensitivity frequency difference is no more than 2.70 MHz.