Mutual coupling in RF powered wireless communication networks for health monitoring

Simultaneous wireless information and power transfer (SWIPT) can be an essential technology for health monitoring. In this paper, the mutual coupling effect for SWIPT is presented with mathematical analysis and simulation results. With two dipole antennas arranged, the total received power for energy harvesting can be maximized as much as 5.6825 μW, which is 1.34 times as large as the uncoupled total received power. With more than two dipole antennas arranged, analytical results show that the received power with the coupling effect into account depends on the spacing of antennas and can increase by more than 50%, compared to the uncoupled case. In single-input multiple-out systems, the channel capacity fluctuates as the interval of antennas is changed. Our analysis shows that the channel capacities of the coupled and the uncoupled case converge because the impact of mutual coupling decreases as the spacing of antennas increases.