Miniaturized Circularly Polarized Implantable Antenna for ISM-Band Biomedical Devices

摘要

A compact circularly polarized antenna operating at 915MHz industrial, scientific, and medical (ISM) band for biomedical implantable applications is presented and experimentally measured. The proposed antenna can be miniaturized to a large extent with the compact size of 15 x 15 x 1.27mm(3) by means of loading patches to a ring-shaped microstrip patch antenna. An impedance bandwidth of 10.6% (865-962MHz) for reflection coefficient less than -10 dB can be obtained. Meanwhile, the simulated 3 dB axial-ratio (AR) bandwidth reaches 14MHz. Finally, the optimized design was fabricated and tested, and the measured results agree well with simulated results.