A Miniaturized Circularly Polarized Implantable Patch Antenna for Bio-Telemetry Applications

Abstract

This paper designs a novel miniaturized circularly polarized patch antenna for wireless implantable medical devices (WIMDs) operating at 1.9 GHz band. The antenna incorporates innovative structures such as meandered S-shaped slits, origin-symmetric shorting pins, and open-ended rectangular slots, resulting in a compact structure with a volume of 32.3 mm ³ . This antenna demonstrates good performance with an impedance bandwidth (IBW) of 18.24% and a broad 3 dB axial ratio bandwidth (ARBW) of 40%, while maintaining a minimum axial ratio of 0.35 dB. This antenna achieves a maximum realized gain of −28.1 dBi in both E and H planes, ensuring efficient signal transmission from in-vivo to external receiving antennas.