A Miniaturized Enhanced Gain Wideband Metamaterial Loaded Planar Inverted F-L Implant Antenna

Abstract The antenna presented in this work is a planar inverted F-L (PIFLIA) implant antenna. The PIFLIA characteristics are improved by loading it with a metamaterial. A metamaterial is an artificial material engineered having properties that are unavailable in nature. The metamaterial is designed using an H-shaped split rectangular resonator as the unit cell. Unit cells are the main element of metamaterials. The antenna is constructed on a substrate material of RO3010. To reduce the antenna's size and enhance its bandwidth, a 2x2 array of the metamaterial unit cell is printed on the opposite side of the substrate. While, the planar inverted F-L antenna is on the upper side of the substrate. This arrangement results in a compact antenna structure. The size of the metamaterial-loaded PIFLA antenna is specified as 16 × 10 × 1.28 mm³. The structure and simulation of the proposed antenna are performed using CST (Computer Simulation Technology) software, a popular tool for electromagnetic simulations. The relative permittivity, ε_r, relative permeability, μ_r, and refractive index, n of the metamaterial unit cell are determined from the scattering parameters and plotted using Matlab, a high-level programming language commonly used for numerical simulations and data analysis. The simulated S_11 of the antenna indicates excellent performance with less than -32 dB return loss in the industrial, scientific, and medical (ISM) band and the medical implant communication services (MICS) band. Additionally, the antenna supports a wide frequency bandwidth, including the MICS band [393.3 – 412.64 MHz], the ISM band [2 – 2.6 GHz], and two additional frequency bands: [1.2 – 1.3 GHz] and [2.8 - 3.6 GHz]. The introduced metamaterial-loaded PIFLA implant antenna is implemented, and the measurements were in consistent with the simulation results.