High-sensitivity optically modulated scatterer for electromagnetic-field measurement

Abstract

The optically modulated-scatterer (OMS) technique is developed for electromagnetic-field-distribution measurement with minimum disturbance to the field under test. In this paper, an OMS with newly designed photoconductive-switching structure is proposed. The performances of the new OMS are evaluated with a monostatic-field-measurement system. Measurement results show that an improvement of 6 to 8 dB in sensitivity is achieved compared to previous OMS devices. The developed OMS was used in an electromagnetic-field-distribution mapping system to measure the field distribution in a cubic phantom radiated by a mobile phone. The results show the suitability of this OMS for specific-absorption-rate measurement application.