Near-field gain measurement of waterproofed shielded loop antenna in tissue-equivalent liquid

In this paper, the shielded loop antenna operated in the liquid as the magnetic-field type reference antenna is designed to estimate SAR of the equipments for the wireless energy transfer system. It is found that our gain measurement method developed for the electric-field type reference antenna can apply to the shielded loop antenna which is one of the magnetic-field type reference antennas: we confirm thatthe theoretical curve of the near-field gain can be derived from the extended Friis transmission formula and the far-field gain can be estimated by curve fitting technique. In the future, we are going to optimize the design parameters of the waterproofed shielded loop antenna and the fitting range to obtain the near-field gain. To decrease the reflection of the shielded loop antenna, some matching circuits should be introduced. In addition, we are going to analyze the magnetic-field components produced by the shielded loop antenna by use of methods of moment.