The influence of Conducting Rough Surfaces on the performance of microwave coaxial filter

Conducting rough surfaces (CRS) of microwave devices introduced by the manufacturing process lead to a variation in the device performance. In course of debugging microwave and millimeter wave devices, we often need to get the accurate electromagnetic models for conducting rough surfaces. In this paper, the electromagnetic characteristics of two-dimensional conducting rough surfaces are studied at microwave frequencies. Machine-fabricated rough surfaces with controlled roughness statistics were examined accurately. The reflecting energy and the absorbing energy of electromagnetic waves are dependent on the surface roughness and the working frequency. Because microwave has a short wavelength, the characteristics of the reflecting and the absorbing energy of electromagnetic waves are affected by the surface roughness strongly. In this paper, the reflecting characteristics and the absorbing characteristics of a series of nickel, aluminous and gold rough surfaces are measured using the broadband integrative vector network analyzer VNA) from 3.95 GHz to 4.25 GHz. The reflecting coefficient and the absorbing characteristics of the rough surfaces are extracted by the measured data and the statistical analysis methods.