Towards multi-mode millimeter wave body area networks for information and power transmission: a co-existence study

While millimeter-wave (mmWave) technologies are often associated with costly applications using large arrays, several inexpensive implementations promise mmWave connectivity closer to the user in Body Area Networks (BANs) applications. Here, we evaluate the potential for multi-mode mmWave links for information and power transfer applications. The co-existence of off-body radiative and on-body wave-guiding mechanisms is experimentally investigated based on state-of-the-art transmission lines and antennas. First, a body-to-body link with at least -50 dB channel gain is demonstrated based on wide-beam microstrip and reflector-backed broadband antennas. Co-existence is then studied experimentally by measuring the coupling between the off-body communication/power transfer antenna and a wearable Single Wire Transmission Line (SWTL), with an ultra-low on-body attenuation of below -0.8 dB/cm around 28 GHz. Less than -40 dB coupling is demonstrated for clearances as low as 1 cm between the antenna and SWTL. The measured results indicate that co-located textile-based antennas and transmission lines can enable multi-mode high-performance body-centric mmWave networks, and highlight the need for interference-countering mechanisms in future high-density BANs