A high capacity near-field inductive coupled MISO communication system for Internet of Things

Communication between things (objects) could involve the use of near-field energy coupling between objects close to each other and radiating-near-field transmission for objects further afield. This paper therefore investigates the capacity of near field magnetically coupled communication systems in free space based on their equivalent circuit models. Only the capacity of near field magnetically coupled single-input-single-output (SISO) and multiple-input-single-output (MISO) inductive systems in free space are analyzed based on their equivalent circuit models. The analysis provides a basis for assessing the general inductively coupled MIMO communication system. We show that preferred architectures for placing the several MISO transmitter nodes are required to maximize the received power. The case for circular orbits around the receiver node which maximizes the received power several times compared to when only one transmitter is used (provided the crosstalk between the transmitters is insignificant) is demonstrated. The binary case on a circular orbit achieves eight times the capacity of a single-input-single-output system using identical system components and devices. We also demonstrate how to limit crosstalk through geometric architectures.