光変調器を用いた電界センサの抵抗装荷エレメントによる周波数帯域改善法

摘要

A wide-band electric field sensor is expected much for measuring impulse noise or evaluating EMC facilities. An electric field sensor using an optical modulator is suitable because it can operate over a wide frequency range and it does not disturb electric field because it does not have metallic materials.This paper describes the method for improving the frequency bandwidth of an the electric field sensor by resistively loaded element. The r esonant phenomenon of the sensor element was controlled by loading resistance on the element. First, the frequency response of the sensor was numerically analyzed by the moment method based on the equivalent circuit of the sensor, and the optimum distribution of resistance was obtained by the analysis. Then a sensor with resistively loaded element was fabricated and itu27s frequency characteristics were measured, and the measured value agreed closely with the calculated value. The frequency bandwidth of the sensor was made two times as wide as that of the sensor with the same long metallic element.