Effect of wireless charging antennas on transmission of an antenna pair through human body

In this paper, the effect of the spiral antenna and the loop antenna for wireless charging on the transmission of an antenna pair comprising an external antenna and an implanted antenna through human body is studied. The transmission characteristic of the antenna pair with a wireless charging antenna positioned between the antenna pair is investigated over the frequency band of 3 – 5 GHz. It is found that the loop antenna features a limited effect on the transmission response while the spiral antenna causes the transmission response to change drastically across the frequency band. It is suggested that a loop antenna, compared to a spiral antenna, is a more efficient wireless charging antenna for an implanted radio system and causes less effect on the transmission between the external and the implanted antenna pair.