The attenuation of electromagnetic waves in a Plasma medium is a complex topic that has attracted the interest of researchers in both fundamental physics and technology. It may be utilized for a variety of applications such as radar cross section reduction, beam steering, etc. In this study, we described a Surface Dielectric Barrier Discharge micro-plasma slab that was positioned in front of a WR62 waveguide to study the interaction properties of electromagnetic waves with plasma. The plasma slab was found to cause a 3-10% attenuation in the S21 parameter, with the amount of attenuation depending on the frequency of the incident wave.