A Dual-Band Printed Inverted-F Antenna for Smart-Card-Sized IoT Devices

This study proposes a compact dual-band printed inverted-F Antenna (PIFA) tailored for integration into miniaturized Internet of Things (IoT) devices. The antenna operates at 2.4 GHz and 5.5 GHz frequency bands, employing a structurally simple yet effective design strategy that introduces an additional resonant branch to achieve dual-frequency operation. A key design constraint assumes a smart-card-sized (53.98 × 85.6 mm2) IoT device, with the antenna confined to one-eighth of the total available area. Despite this spatial limitation, the antenna demonstrates notable performance, achieving realized gains of 2.48 dBi and 3.6 dBi at 2.4 GHz and 5.5 GHz, respectively, along with radiation efficiency exceeding 80% across the targeted bands. Owing to its compact, single-layer structure and efficient radiation characteristics, the proposed design presents a promising solution for space-constrained wireless applications in next-generation IoT systems. © 2025 IEEE.