Measured Results of Input Resistance of NMHA in a Body Phantom

In recent years, the development of healthcare monitoring devices require sensor antennas with high performance and small size. Normal-mode helical antenna (NMHA) can achieve high efficiency when antenna structure is designed self-resonant. However, when antenna was placed in a human body, it was reported that an antenna efficiency was decreased owing to increase of input resistance. To ensure the input resistance through experiment is important. In this paper, measurement is performed by using a human body phantom. Input resistance results of measurement and simulations agree rather well.