Compact metamaterial-integrated wireless information and power transfer system for low-power IoT sensors

This paper presents the realization and assessment of a compact metamaterial (MTM)-integrated wireless information and power transfer (WIPT) system. Developed WIPT is tailored to facilitate numerous Internet of Things (IoT) sensors operating at the low-power regime. Generally, WIPT is accomplished with a system possessing two operating bands. Therefore, the dual-band system working at frequencies of 405 MHz and 900 MHz was proposed. WIPT is achieved by coupling two defected ground structure-based resonators that are designed by cascading two single-band resonating structures. Then, MTM with the double negative characteristics at WIPT's operating frequencies was incorporated, which led to the performance enhancement. The power transfer efficiency of WIPT was increased by 14% and 7% at 405 MHz and 900 MHz, respectively, when the resonators were coupled at 20 mm. It is worth mentioning that WIPT and MTM share the same area of 25 × 25 mm2 to keep the compactness of the overall system. The WIPT system was evaluated in terms of charging time for two low-power IoT sensors. The powering time was approximated considering two scenarios: using only one band and two bands simultaneously. The provided analysis in both cases reveals that MTM-integrated WIPT aids in the significant reduction of a charging cycle.