Gain Enhancement of a Compact Implantable Dipole for Biomedical Applications

A new compact implantable planar dipole with an enhanced gain performance and a relatively low specific absorption rate (SAR) is proposed. In the proposed dipole, a part of each arm is shaped as a folded meander-line structure, especially designed to have a minimal size and cover the medical device radio communications service band (MedRadio, 401-406 MHz). It is shown that using this technique, the gain of the antenna can be increased without compromising miniaturization. The antenna has a peak realized gain of -23.7 dBi and its total volume is 20 mm3. The antenna has a relatively low SAR, so that the maximum transmitting power satisfying the regulatory limitation is 7.7 dBm. The SAR simulation results are confirmed experimentally.