Compact broadband implantable monopole antenna with gain enhancement

This study proposes a gain enhancement design for a CPW fed compact broadband monopole antenna for biomedical implant applications. A U-shaped ground plane shrinks the antenna dimension. An extension strip of the U-shaped ground can improved the antenna gain by enhancing the capacitive coupling and directivity. The dimension of the proposed antenna is 0.0245λ₀ × 0.0245 λ₀ × 0.00176λ₀ mm³. The measured antenna bandwidth is 55.3% (374 MHz ~ 660 MHz), and the simulated antenna gain improved by 3.7 dB (from -26.1 dBi to -22.4 dBi). Not only does this design achieve high gain but also low SAR value characteristics can be obtained.