A Novel Circularly Polarized Implantable Patch Antenna for Biomedical Applications

In this letter, a compact single-feed circularly polarized patch antenna working at 2.45-GHz industrial, scientific, and medical band is proposed. The proposed antenna is miniaturized by cutting four identical rectangular slits in the radiation patch, and its whole size is 85.4 mm
³
. An asymmetrical cross slot is etched in the center of the patch so that the circular polarization is realized. The introduction of shorting pin further broadens the axial-ratio (AR) bandwidth. An impedance bandwidth of 15.1% with an AR bandwidth of 31% is achieved in a single-layer human skin tissue phantom, which makes the proposed antenna perfect for biomedical applications.