Design of Miniaturized Incident Angle-Insensitive 2.45 GHz RF-Based Energy Harvesting System for IoT Applications

• Published in: IEEE transactions on antennas and propagation Vol. 70; no. 5; pp. 3781 - 3788
• Main Authors: Park, Jeong-Su, Choi, Yu-Seong, Lee, Wang-Sang
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Angle insensitive; Antenna design; Antenna measurements; Antennas; Charge pumps; Circuit boards; Circuit design; Dipole antennas; Dual polarization (waves); dual-polarized; Efficiency; Energy harvesting; Impedance matching; Internet of Things; miniaturized; Power consumption; Power sources; Printed circuits; Radio frequency; radio frequency (RF)-based energy harvesting system; rectifier circuit; Rectifiers; RF signals; Substrates
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2021.3137481

Using a license-free industrial, scientific, and medical (ISM) frequency band as 2.45 GHz, a miniaturized incident angle-insensitive radio frequency (RF) energy harvester design for the Internet-of-Things (IoT) applications is proposed. For incident angle insensitivity of ambient RF energy and a low-profile compact design, the proposed harvester is used to a two-layer printed circuit board (PCB) substrate, which consists of orthogonally deployed antennas with an <inline-formula> <tex-math notation="LaTeX">LC </tex-math></inline-formula> balun, impedance matching, and Dickson charge pump circuits at each layer. The dual-polarized antenna for miniaturized design uses a bowtie-shaped meander dipole antenna having orthogonal arrangement. By measuring the efficiency of each diode stage of the rectifier circuit, a two-stage Dickson charge pump circuit with optimal efficiency was selected, and the dc outputs of the two rectifier circuits are connected in parallel. This rectifier circuit has a conversion efficiency of up to 71.4% and harvests approximately 1.6 times more power than a single-polarized circuit from any incident ambient RF signal. Due to its compact size and improved harvesting power at various incident angles, the proposed energy harvester can act as a power source, such as many kinds of ultralow power consumption systems, such as IoT sensors and medical applications.