An electro-optic measurement system for electric fields near RF and microwave radiators and scatterers

[摘要] ENGLISH ABSTRACT:An electro-optic sensor system was developed which uses the modulated scatterertechnique [1] to measure the fine structure-amplitude and phase-ofelectric fields with the minimum of perturbation. The theory for the techniqueis discussed in detail, with the Lorentz Reciprocity theorem as foundation.The system is also treated as a general two port and solved interms of the impedances present. This comprises self impedances and mutualimpedances.The signals scattered by the dipole scatterer are modeled as amplitude modulatedsignals and a detailed detection scheme is presented. The detectionof the signals is done by a digital correlation process. This is quite similar tosynchronous detection.A detailed sensitivity analysis is presented that was used to determine thequality of the system. This analysis is backed by a practical sensitivitymeasurement. A few antennas and scatterers are measured in the X-bandusing the system, and results are compared with theory. These systemsinclude a pyramidal horn, an E-plane sectoral horn and a simple waveguide.Half plane diffraction by a metal sheet is also presented.The practical implementation of the theory is emphasized.

[发布机构] Stellenbosch University