L Shaped via based Mushroom type High Impedance Structure

High-impedance Electromagnetic Band-Gap structures (EBG) surfaces have the capability to forbid flow of EM waves in a given band which and therefore surface waves in case of planar antennas like mictostrip antenna can be minimized with this characteristics of EBG plane. Shape, size, symmetry, and material used in their construction defines their operating band. In this research, a novel compact EBG structure also called high impedance structure (HIS) is proposed. The design is achieved through incorporation of ‘L’ shaped via to conventional mushroom type EBG/HIS instead of straight vias. The design includes distribution of square patches over substrate material below which there exists a ground plane. Vias passing through the substrate connecting square patches and the ground plane are also part of its design It has been observed that operating frequency of L shaped via based EBG is much lower than that of conventional mushroom type EBG/HIS having straight vias. Alternatively, we can say that size reduction has been achieved through incorporation of L shaped via to the EBG/HIS resulting in 62.5 % of size reduction. All the designs and simulations are carried out in CST microwave studio.