Miniaturized Wide Tri-Band Antenna for Scalp Implantable Applications

A miniaturized scalp-implantable antenna, operating in the wireless medical telemetry service of 1395−1400 MHz for data telemetry, midfield band of 1824−1980 MHz for wireless power transfer, and industrial, scientific, and medical (ISM) band of 2400−2483 MHz for controlling signals, is developed. The proposed antenna has the dimensions of 7.2 mm × 7.7 mm × 0.762 mm (0.0336λ
0
× 0.0359λ
0
× 0.0036λ
0
at 1.4 GHz) by etching a serpentine radiating patch and a defective ground plane. In skin phantom with an implanted depth of 3 mm, –10-dB impedance bandwidths of 1400 MHz (11.5%), 1870 MHz (19.5%), 2450 MHz (14.5%) are obtained. In the off-body direction, peak gains reach −27.4, −21.4, and −24.1 dBi at 1400, 1870, 2450 MHz, respectively. The designed antenna is coated with a biocompatible film to ensure safety. Moreover, it is integrated with the rest of the electronics and re-matched by adjusting one of geometrical parameters of the ground slots. Due to the merits, the proposed antenna has the potential to be implanted in the scalp.