In present years, surface mounted piezoelectric wafer active sensors (PWAS) or piezoelectric patches are gaining popularity for onboard Structural Health Monitoring (SHM) systems. Through experimental investigations, it is apparent that several uncertainties are associated with the sensor signals. Proper understanding of the influence factors may provide insight to such uncertainties. Optimal placement of sensors is also a big challenge. In this paper, we have tried to report the pattern of wave field generated by the surface mounted actuators and the pattern of wave field developed near the sensors using a semi-analytical modeling technique called Distributed Point Source Method (DPSM). The surface mounted sensors/actuators are glued to the surface of the structure. Therefore, the contact between sensors and the host material is of utmost importance in transmitting energy into the host material. Long term interest of this research is to show the feature based differences in generated signals due to various types of contacts and debondings. However, in this paper we have addressed the most common type of contact called Gaussian contact which has a practical significance. In the near future, through this research, we can address issues related to other types of contact that frequently occur. This will help us to better understand the generated signals and quantify the uncertainties due to contact condition.