The spectral Element Method (SEM) is one of the forms of the finite element method in the frequency domain. It has become quite popular in structural health monitoring applications. Wave equations are transformed into the frequency domain using appropriate forward transforms. The governing equation is solved to get the desired parameters. The spectral finite element method is a numerical method evolved using Fast Fourier Transform. This book is primarily concerned with the development and coding of a spectral plate element to analyze the harmonic response of simply supported plates in the mid to high-frequency range. The development includes the governing PDE, displacement field, shape function, and dynamic stiffness matrix.