Miniaturized Duplex Implantable Antenna for Wireless Data Communication and Power Transfer

Abstract

This paper presents a novel duplex implantable antenna for simultaneous wireless power transfer and data telemetry in wireless capsule endoscopy (WCE) applications. The proposed antenna operates at 1.8 GHz (wireless power transfer) when Port-1 is excited and 2.4 GHz (data telemetry) when Port-2 is excited. The antenna’s performance has been evaluated within a simulated human stomach phantom to closely mimic real-world implantation scenarios. Shorting pins, semi-circular and open-end slots techniques are used to make the antenna smaller, resulting in a compact volume of 8.17 mm3. Slots of different lengths on both patches generate different resonant frequencies. A rectangular slot with a width of 0.4 mm and a length of 6.3 mm is introduced in the center of the ground plane, achieving an isolation level better than 28 dB. The antenna provides nearly omnidirectional patterns at both frequencies with gain values of -24.7 dBi at 1.8 GHz and -23.9 dBi at 2.4 GHz. Link budget and specific absorption rate (SAR) are investigated. The fabricated prototype is tested in minced pork meat, with good agreement between experimental and simulation results. The antenna system has a compact size, low coupling levels, and can simultaneously transmit data and receive power without the need of a multiplexer. With these attributes, the proposed design is a promising candidate for WCE devices requiring simultaneous data communication and power reception.