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 mm Wave con-nectivity closer to the user in Body Area Networks (BANs) applications. Here, we evaluate the potential for multi-mode mm Wave 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.