Wireless body area communication using electromagnetic resonance coupling

In this paper, a new highly efficient wireless communication link around human body using electromagnetic resonance coupling was proposed and investigated. The communication between wearable devices located on forearm and upper arm, like a wristwatch or armband, is assumed as a model for body area communication. The transmission characteristics S₂₁, between transmitting and receiving antenna which is put on forearm and upper arm, respectively, like a wristwatch or armband, were analyzed and measured. As a result, the transmission characteristics S₂₁ showed the maximum value of -12 dB, and was excellent compared with that of conventional body area communication using the electrodes in contact with the body. Moreover, the SAR of the body was less than a three-hundredth compared with the safety limit of 2 W/kg. Therefore, we confirmed that the wireless communication link using magnetic resonance coupling is useful for body area communication.