Abstract:In response to the pressing demands of current wearable medical devices for wide bandwidth, multi-functional integration, and biocompatibility, this paper presents the design of a hybrid reconfigurable dual-band antenna based on an eco-friendly flexible paper substrate. The proposed antenna employs photo paper as the dielectric substrate, with compact dimensions of 22×25×0.27 mm3, offering excellent flexibility and lightweight characteristics. Dual-band operation is achieved through stub-loading techniques, while integrated PIN diodes function as RF switches. By controlling their ON/OFF states to alter the current paths, the antenna achieves four reconfigurable operating modes in both frequency and radiation pattern: specifically, two dual-band directional radiation modes, one low-frequency omnidirectional radiation mode, and one high-frequency omnidirectional radiation mode. The antenna structure was fabricated on the photo paper substrate using the screen-printing technique with silver paste, and the prototype was completed by integrating PIN diode control units via a bias circuit module. The measured results demonstrate that the antenna operates effectively in either dual-band or single-band modes across the 2.4 and 5.8 GHz bands. Across all modes, the -10 dB impedance bandwidth exceeds 20%, the peak gain remains stable at approximately 3 dBi, and the radiation efficiency is above 60%. Under bending conditions with a curvature radius of 20 mm and when loaded with a human tissue model, the antenna maintains stable impedance matching and radiation performance, demonstrating good structural robustness and wearability. The specific absorption rate (SAR) values are 1.145 W/kg at 2.5 GHz and 1.312 W/kg at 6 GHz, both complying with international safety standards and meeting the electromagnetic safety requirements for wearable devices used on the human body. The combination of eco-friendly materials, a compact structure, and hybrid reconfigurability endows the proposed antenna with significant potential for practical applications in short-term medical monitoring and body area communication wearable systems.