Miniaturized Frequency Reconfigurable Patch Antenna for Wireless Power Transfer

This paper introduces a miniaturized frequency-reconfigurable receiving antenna incorporating a tri-turn square-shaped complementary spiral resonator (3-SCSR) for Wireless Power Transfer (WPT). The proposed planar antenna features a simple design, with compact dimensions of 50 mm × 50 mm, and supports four operating modes. To achieve miniaturization, the 3-SCSR structure is embedded into the ground layer of the patch antenna. Three PIN diodes are integrated with the 3-SCSR structure on the underside, enabling reconfigurable operation across single, dual, and tri-band modes over a wide frequency range (0.205–1.7 GHz), achieving a peak antenna gain of 2.84 dBi. Additionally, a matching network and rectifier designed for 1.5 GHz enable RF-DC conversion, delivering 50% efficiency at an input power as low as –10 dBm.