With the increasing demand for clean energy and a good reliable form of energy, magnetostrictive energy harvesters have continuously developed, which derive energy from ambient vibrations. A perpetual source of electrical energy can be extracted from structural vibrations. This sensor is made up of Gallium (Ga) and Iron (Fe) alloy and allows it to generate electrical energy from structural vibration. This paper deals with a comparative study of different sizes of stainless steel, Galfenol, and their respective output voltages. The goal of this paper is to find an efficient configuration for a sensor. In order to evaluate the performance of the proposed design, we conduct various simulations for various dimensions of a prototype using COMSOL Multiphysics.