Improvement in Transmission Characteristics for Magnetically Coupled Body Area Network by Using a Parasitic Wearable Coil

Abstract

　In this research, to improve the transmission characteristics, we proposed introducing a parasitic relay coil without a power source, as a relay device, and investigated transmission characteristics and electromagnetic field distribution. From the results, it was confirmed that the insertion of the relay coil between the transmitting and receiving coils improved the transmission characteristics by up to 8.9 dB, except when the relay coil was located close to the trans-mitting or receiving coils. In addition, it was also confirmed that the magnetic field excitation in the transmitting coil was induced by the relay coil and this enabled effective transmission to the receiving coil. Thus, the effective improvement in the transmission characteristics by introducing the relay coil was confirmed.