A Dual-band Ultra-Miniaturized Scalp-Implantable Antenna for In-Body Bioelectronics

In this work, an ultra-miniaturized implantable antenna operating in dual frequency bands, including the Industrial, Scientific, and Medical (ISM) band (902–928 MHz) and Midfield band, is proposed. The key feature of the proposed antenna is its small volume ($6\ \text{mm}\times 6\ \text{mm}\times 0.5\ \text{mm}=18\ \text{mm}^{3}$) compared to the existing works. And the antenna size reduction is mainly achieved by employing a spiral-shaped radiator, a shorting strategy and slots in the ground plane. The results demonstrate −10dB fractional bandwidths of 13.4% (871 - 994 MHz) and 6% (1398-1485 MHz). And the peak realized gain values are −32.8 dBi and −24.8 dBi at the desired bands, respectively. The designed antenna can be a potential candidate for the scalp implantable bioelectronics.