New imitated equipment with optical powering system for evaluating anechoic chamber characteristics

In order to evaluate the characteristics of an anechoic chamber, a new optically driven imitated equipment with optical powering system is developed. The optical powering system consists of high power laser diode, optical fiber and photovoltaic cells. This serves as the electric power source which does not use any metal cables and operates for a much longer period of time than batteries. By comparing the radiation characteristics of the imitated equipment using the optical powering system with those when battery was used, it is clear that the radiation characteristics of the imitated equipment with the two power sources agreed with each other. In addition, the correlation of radiated electric field from the imitated equipment between semi and fully anechoic chambers was studied experimentally and theoretically by comparing with the results when other kinds of antennas were used as the radiating source. As a result, it was revealed that the measured correlation for the imitated equipment were in relatively good agreement with that for the broadband antennas; and the calculated correlation for the imitated equipment showed the same tendency as that for a dipole antenna. Moreover, we measured the correlation of radiated electric field from the imitated equipment for semi anechoic chambers with imperfection which was realized by placing a metal board on one side of the walls. Since the correlation for the imitated equipment was different from that for the log-periodic antenna, we concluded that there is a need to measure radiated electric field by using the imitated equipment, in addition to NSA measurements by the log-periodic antenna.