This article deals with the effect of adhesive bond on piezoelectric ceramic (PZT) patch-structure interaction system and the resulting effect on admittance signature, which has a major impact on the electromechanical coupled phenomena pertinent for the electro-mechanical impedance technique. The adhesive bond acts as an elastic medium which facilitates the transfer of stresses and strains developed due to piezo displacement and also couples the impedance of PZT patch with that of the host structure. In this work, the force transfer mechanism is studied along the length of the PZT patch as also the variation of the shear stress and strain along the bond. This article presents a numerical approach to study the inclusion of shear lag in the electro-mechanical impedance model through commercially available finite element (FE) simulation software. The results are compared with existing analytical as well as experimental data. Parametric study of the FE shear lag model is carried out to examine the effect of piezo-mechanical parameters on the admittance signature.