Constant near-field gain for folded loop antennas in normal saline at 6.78MHz

It is required that specific absorption rate of mobile devices operated in HF band should be evaluated by using a calibrated probe. In this paper, we propose an extension of reference antenna method, which is one of methods for calibrating the probe. As a reference antenna, we examine a circular folded loop antenna immersed in normal saline solution. If its perimeter is well selected, constant near-field gain can be realized in its near-field region. And, to reduce its size, the number of folding should be larger. Also, we show the validity of estimated formula for electric field intensity radiated by the reference antenna with its near-field gain.