Broadband circularly polarised implantable antenna for biomedical applications

A compact, broadband and single-fed circularly polarised implantable patch antenna is numerically evaluated and experimentally demonstrated for industrial, scientific, and medical band (2.45 GHz) biomedical telemetry application. By inserting a cross-shaped slot with unequal-length arms in the ground plane, the proposed antenna can obtain improvement for both impedance bandwidth and axial ratio (AR) bandwidth, without increasing the backward radiation. The simulated −10 dB impedance and 3 dB AR bandwidths are 16.15% and 6.09%. The measured impedance bandwidth is 14.03%. The overall antenna size (including the superstrate) is 10 × 10 × 1.27 mm3.