The main focus is to obtain triband operation within the frequency range of 1–4GHz. Miniaturization of the overall size of the antenna is to the core of our effort. A novel approach is adopted for evaluating the relationship of directivity with the spacing height of copper grid layer over the patch, termed as radome structure by the present team of authors is presented. Numerous designs and models of radome structure are conceptually solved and evaluated using finite element method (FEM) based High Frequency Structure Simulator (HFSS) software tool. Single copper grid layer over the patch antenna for achieving high directivity is described. Newton's divided difference method is applied on the radome structure for evaluating the performance parameters of the antenna. A global formula is developed to indicate the relationship of the directivity with the spacing height of the patch antenna by varying the distance of copper grid layer and observing its effect on the directivity of the patch. A metamaterial cover over the microstrip patch antenna is reported to improve the directivity of the slotted patch antenna.