Metamaterial‐inspired wideband biocompatible antenna for implantable applications

Abstract

A compact wideband coplanar waveguide (CPW)‐fed antenna is designed for body implantable applications. The proposed antenna has an electrical dimension of only 0.42 λ × 0.42 λ × 0.0072 λ at 2.3 GHz resonating frequency. Fractional bandwidth of 93.5% (1.35–3.5 GHz) is achieved with the low‐profile antenna. To understand the extent of miniaturisation and bandwidth enhancement of the antenna, the characteristic modal analysis is performed. The wideband feature is achieved with the application of asymmetric complementary split‐ring resonator structure through multiple mode excitations. Additional miniaturisation and impedance matching are obtained with a pair of asymmetrical arc‐shaped annular ring slots within the main radiator. The substrate and radiator have been realised using silicon and gold due to their inherent property of excellent bio‐compatibility with the human body. Single layer, as well as multi‐layers phantom model, was used to assess the performance of the antenna. Owing to the inherent wideband feature of the designed antenna, it is able to cover the desired band efficiently even after detuning in different phantom models. The designed antenna is tested in vitro with the development of proper muscle mimicking liquid and the measured results are found to be in good agreement with the simulated ones.