脉冲微波辐射场准确功率测量法探讨

Accurate Measurement of Power Density of Pulsed Microwave

脉冲微波作用于生物体时 ,其辐照剂量通常由HP8991A脉冲功率计测量辐射器的辐射功率 ,再依据生物体至辐射器之距离按公式推算生物体被辐照的剂量。研究结果表明 :1 用接收喇叭 (替代生物体位置 )连接衰减器、功率探头、脉冲功率计 ,既避免公式求算法的推导误差 ,又可对微波暗室任意一点直接测量 ;2 以吸收系数相同的纯净水在同等布局下进行参比对照 ,体现微波吸收的水温增值 (ΔT)与功率密度变化显著相关r=0 9860 ,p <0 0 1 ,表明测量的可信 ;3 证明波源辐射器发射的微波束均匀场强实际是锥形投影 ,这样更有利于被辐照生物体准确安置于均匀场投影区内 ,提高了动物所受辐照剂量的均匀度 ;4 接收喇叭与微波源辐射器的H、E极化方向保持一致则测量准确 ,极化方向错位 ,可使测量误差增大 3倍以上。

When organism is exposed to pulsed microwave, the dosage is usually measured by a HP8991A radiometer. The power of irradiation is calculated according to the distance. In our present study, the findings are as follows:①The power of pulsed microwave could be detected by a system including decay and power detectors. Direct measurement could be more accurate than formula calculation and can detect the power density at any spot of the dark room. ②Increase of the temperature is correlated with the power density of pulsed microwave(r=0.9860,p<0.01).③Projection of microwave beam is like a pyramid after transduction to the dark room. This facilitates exposure subjects to be equally irradiated.④The power detectors should be kept in the same direction of H and E fields in order to increase the accuracy of measurement.