An Implantable Broadband Antenna for ISM-Band Applications with a Small, Multi-Slot Design

The human body is a complex dielectric environment, with each tissue layer possessing distinct dielectric constants, which can significantly impact the performance of antennas. To address the issue of unstable communication in implantable devices, a miniaturized, broadband, implantable antenna designed for the Industrial, Scientific, and Medical (ISM) band (2.4-2.48 GHz) is presented. The antenna has a compact volume of merely 6×6×0.53 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>, achieved by introducing a zigzag slot, symmetrical rectangular slots, and multiple identically sized rectangular slots on the metallic patch, thereby realizing miniaturization. The antenna utilizes alumina ceramic as the dielectric substrate, covered with silicone on the top layer, endowing the antenna with biocompatibility. A rectangular ground plane is etched beneath the substrate to extend the antenna's impedance bandwidth. To simulate the antenna's in vivo working environment, simulations were conducted within a simulated human muscle tissue model. Test results indicate that the antenna's operational bandwidth reaches 15% (2.23-2.57 GHz), fully covering the ISM band.