Compact coplanar waveguide fed implantable antenna with hybrid split-ring resonators

摘要

This communication presents the design of a miniaturized coplanar waveguide (CPW) fed antenna backed by split-ring resonators (SRR) for implantable applications. The proposed antenna is designed to operate at Industrial Scientific and Medical (ISM) band (2400-2483.5 MHz). The antenna has a dimension of 0.1856 λeff × 0.2088 λeff × 0.002946 λeff with a substrate thickness of 0.127 mm. The antenna miniaturization is achieved by using a meandering microstrip line on the top and SRR at the bottom layer. A Superstrate of thickness 0.381 mm is used to improve the impedance matching and to reduce the tissue contact with the radiating patch. The antenna prototype is fabricated and measured using porcine tissue to verify the suitability of the design. From the study, it is inferred that the proposed SRR backed CPW antenna significantly improves the realized gain. The proposed antenna has a gain of −22.7 dB without SRR and an improved gain of −15.05 dB with SRR at 2.45 GHz. The specific absorption rate (SAR) is 0.651 W/Kg for 1 g of tissue. The input power is maintained at 1 mW for satisfying the IEEE/ANSI standard. Furthermore, the proposed antenna's novel features are compared with the state-of-the-art implantable antennas.