Feasibility evaluation of near-field communication in clay with 1-mm3 antenna

We are working toward actualizing a real-time 3D modeling system that uses a sensor network consists of many 1mm³-class sensor nodes in plastic clay. This paper focuses on 1mm³-class small antenna and discusses the feasibility of near-field communication with such small antennas. In order to clarify communication characteristics for evaluating the feasibility, we designed 1mm³-class spiral antennas having three different resonant frequencies and carried out 3D full-wave electromagnetic simulations. When two antennas are embedded in a clay model with 10mm distance, the maximum |S₂₁| values at 30MHz, 340MHz, and 1.3GHz are -81.1dB, -69.6dB, and -64.7dB, respectively. This simulation result suggests that the near-field communication with 1mm³-class antennas is feasible.