A Highly Compact Intra-Ocular Antenna Characterization for Retinal Prosthesis Application

This work presents a miniature intra-ocular (IO) antenna for retinal biomedical implants. Capacitive radiator loading offered miniaturized dimensions of 2.5 × 2.5 × 0.254 mm 3 , and the electrical dimensions, are λ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> /50 × λ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> /48 × λ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> /500. The proposed IO antenna is based on a modified Hilbert geometry resonator and an inverted L-slot, Vertical slots are used in the ground plane to obtain a wider bandwidth (561 MHz) with proper impedance matching, and it operates at 2.4 GHz in the industrial, scientific, and medical (ISM) band. A simplified multi-layered human eye model is developed to simulate and analyze the proposed IO antenna for design evolution in a realistic environment. The proposed IO antenna has simulated realized gain at 2.4 GHz of -20.3 dBi, and its radiation pattern is omnidirectional in the H-plane and directional in the E-plane. For 1W of input power, the SAR values for 1g and 10g tissues were found to be 289 [W/kg] and 68 [W/Kg] at 2.4 GHz, respectively.