Analysis and design of broadband simultaneous wireless information and power transfer (SWIPT) system considering rectifier effect
The deployment of internet of things (IOT) devices in several applications is limited by their need of having batteries as a power source. This has led many researchers to make efforts on simultaneous wireless information and power transfer (SWIPT) systems design. Increasing the bandwidth provides higher capacity; however, due to the narrowband response of conventional power transfer subsystems, power delivery is decreased. In order to design an optimum wideband SWIPT system, first, a realistic model of the system, including antennas and rectifier, should be developed. Then, proper methods to increase the bandwidth of subsystems for optimum power delivery can be proposed. In this paper, a wideband SWIPT system (300 MHz bandwidth at the center frequency of 1.44 GHz) while considering realistic limitations of antennas and rectifiers is designed. To optimize the system performance, a novel power allocation method is proposed. Using this algorithm, Pareto fronts of Shannon channel capacity versus power delivery in three scenarios (broadband antennas without considering rectifier, broadband antennas with narrowband rectifier and broadband antennas with broadband rectifier) are compared. The results show that, without considering the realistic behaviour of the subsystems, the performance is largely overestimated. Furthermore, this model allows for designers to optimize each subsystem directly and assess its effect on the overall SWIPT system performance.