Miniaturized Implantable Antenna with Ultra-Wide Bandwidth Characteristics for Leadless Pacemakers

This article presents a miniaturized antenna with a broad bandwidth tailored for use in cardiac leadless pacemakers. The proposed antenna has a compact size with a footprint of
$9.44 mm^{3}$
, and an ultra-wide bandwidth of 3380 MHz, which effectively mitigates detuning effects. This bandwidth covers the frequencies from 0.77 GHz to 4.15 GHz, ensuring optimal performance across medical frequency bands, including ISM, (WMTS), and the midfield bands. The achievement of this ultra-wide bandwidth is attributed to the insertion of a meandered line in the ground plane and a large rectangular slot in the patch. Furthermore, to ensure patient safety, Specific Absorption Rate (SAR) examinations were conducted within a homogeneous heart phantom (HHP). In this HHP scenario, the proposed antenna, housed within a dummy leadless pacemaker, demonstrated high gain values of -27.8 dBi, -28.9 dBi, and -30.5 dBi at 0.915 GHz, 1.4 GHz, and 2.45 GHz, respectively.