Broadband Integrated Waveguide Rf To The Electric Field Sensor

With the progress in electronic equipment, evaluation of the electromagnetic compatibility (EMC) of the equipment has become an important issue. To evaluate the EMC it is necessary to accurately understand the electromagnetic field surrounding the equipment. Therefore, various sensors for measuring the electric field have been developed. Among them, since the electric field sensor using a Mach-Zehnder interferometer features wide bandwidth, high sensitivity, and high resolution, its application in EMC measurement is experted..First, this paper has introduced the operation principle of the optical waveguide electric field sensor, and built a equivalent circuit model of the electric field sensor and a system model. And then the sensitivity, the frequency response and the linearity dynamic range are analyzed detailedly.The simulated results show that we can improve the sensitivity by setting the optical bias atπ/2, reducing the gap of electrode, increasing the overlap integral factor, reducing the insert lose, adopting suitable segmentation number, increasing the electrode length, increasing the optical power, reducing the wavelength and the relative intensity noise and reducing the receive bandwidth; obtain the wider bandwidth utilizing reducing the electrode length and the capacitance of modulator, segmentation the electrode; increase the dynamic range using lowering noise, increasing the optical power at the detector and lower optical bias.We designed and fabricated 3 optical electric field sensors with segment electrode, basing on the analyses .The isotropic electric field probe has been fabricated using 3 sensors, and its characters were measured, including electrostatic field measurement, frequency response measurement, sensitivity measurement and dynamic measurement. The±3 dB bandwidth is from 1 MHz to 1 GHz and the±5 dB bandwidth is up to 2.5 GHz. The minimum detectable electric field strength is 10~20 mV/m at frequency bandwidth of 3 Hz. The dynamic range is 80 dB at 250 MHz. The isotropy is±3 dB at 200 MHz, and±1.5 dB at 2GHz.