Fabrication and characterization of radome structure

This paper presents the design issues, modeling, fabrication and characterization of a radome structure, a metamaterial cover over the slotted patch antenna for triband operation with center frequency 2.45 GHz. The dimensions of the slots patterned over the patch antenna are designed to control the lower resonant frequency and the bandwidth. The paper presents the selection of the best optimized dimensions of the slotted patch antenna and metamaterial cover to control the resonant frequencies and bandwidth of the antenna. The experimental results are presented thoroughly and compared with the analytical calculations. An analytical method, Newton´s divided difference method is utilized to predict the features of the simulation results, implying that within a certain frequency range, the spatial height of the metamaterial cover can be adjusted for maximum directivity attainment. Negative value of permittivity and permeability are obtained due to the use of metametarial cover over the patch antenna. S-parameters, directivity and radiation patterns as performance matrices are obtained using the software tool High Frequency Structure Simulator version 11. These parameters are used to retrieve the effective permittivity and permeability. Numerous simulations have been carried out for different heights of the cover from the patch antenna in the microwave regime. The optimally simulated structure is proposed for the application of metamaterials as antenna cover to primarily enhance directivity by minimizing its refractive index in negative regime. Further design includes review and critical discussions on the effect of using different substrate materials for the patch antenna.