Advancing IoT wireless sensor nodes with a low profile multiband RF rectifier based on multi-stub J-Inverter network

Abstract

In this paper, a unique RF rectifier design is introduced, employing a multi-stub J−Inverter impedance matching network (IMN). The structure of the IMN comprises a series of three sections with multiple stub tuning elements interconnected via a meandered line (MDL) to form multi-frequency susceptance blocks. The rectifier has been developed to work at frequency bands: 1.84, 2.10, and 2.45 GHz. These frequencies align with the designated bands for GSM/1800, UMTS/2100, and Wi-Fi, respectively. By implementing a complete ground architecture, the rectifier utilizes a minimal space of 0.57λg×0.3λg on the RT/Duroid 5880 PCB board. The experiment’s outcomes show the proposed RF rectifier’s effectiveness in converting radio frequency (RF) signals into direct current (DC) power (RF-to-DC). The results indicate PCE values of 32.70%, 27.60%, and 24.50%, corresponding to input powers of -20 dBm at the targeted operational frequencies. Additionally, the rectifier design proposed within this study achieves its peak RF-to-DC PCE of 75.30% when energized by an input power of 3 dBm. Moreover, notable stability is demonstrated by the rectifier, sustaining an RF-to-DC PCE surpassing 50% throughout the frequency range spanning 1.7 to 2.4 GHz. This robust performance remains consistent even at lower input power levels, such as -10 dBm Furthermore, the rectifier can produce a direct current (DC) voltage output ((VDC)), measured at 0.411 V in an ambient context. The integration of the rectifier with the power management module (PMM), facilitated through the utilization of the bq25504-674 evaluation module (EVM), successfully established a connection within the PMM system. This integration yielded a (VDC) of 1.270 V. Hence, through proficient management of the proposed RF rectifier, it becomes feasible to utilize ambient RF signals to energize a range of low-energy devices effectively.