Miniaturized Triple-Band Circular- Polarized Implantable Patch Antenna for Bio-Telemetry Applications

This letter presents a triple-band antenna with circular polarization (CP) behavior embedded in a lossy tissue for bio-telemetry applications. The triple bands are the Industrial, Scientific, and Medical (868–868.6 MHz and 2.4–2.4835 GHz) bands and the midfield band (1.824–1.98 GHz). These bands are used for physiological information telemetry, power-saving, and wireless power transfer in medical devices. CP behavior at three bands is the key feature of the designed implantable antenna, compared with literature dual-band CP antennas. Moreover, the size of the designed antenna is compact of 50.8 mm
$^{3}$
. Finally, the specific absorption rate and link margin are calculated for the consideration of health safety and reliable communication aspects.