A Compact-Size Multiple-Band Planar Inverted L-C Implantable Antenna Used for Biomedical Applications

In this paper, a compact-size multiple-band planar inverted L-C implantable antenna is proposed. The compact antenna has a size of 20 mm × 12 mm × 2.2 mm and consists of planar inverted C-shaped and L-shaped radiating patches. The designed antenna is employed on the RO3010 substrate (ε_r = 10.2, tanδ = 0.0023, and thickness = 2 mm). An alumina layer with a thickness of 0.177 mm (ε_r = 9.4 and tanδ = 0.006) is used as the superstrate. The designed antenna operates at triple-frequency bands with a return loss of -46 dB at 402.5 MHz, -33.55 dB at 2.45 GHz, and -41.4 dB at 2.95 GHz, and provides a size reduction of 51% compared with the conventional dual-band planar inverted F-L implant antenna designed in our previous study. In addition, the SAR values are within the safety limits with a maximum allowable input power (8.43 mW (1 g) and 47.5 mW (10 g) at 402.5 MHz; 12.85 mW (1 g) and 47.8 mW (10 g) at 2.45 GHz; and 11 mW (1 g) and 50.5 mW (10 g) at 2.95 GHz). The proposed antenna operates at low power levels and supports an energy-efficient solution. The simulated gain values are -29.7 dB, -3.1 dB, and -7.3 dB, respectively. The suggested antenna is fabricated and the return loss is measured. Our findings are then compared with the simulated results.