Resonance frequency behaviour of microstrip resonators for thin film overlays

The effect of very thin overlays on microstrip resonating structures is studied theoretically and compared with reported experimental results using screen printed dielectric pastes. A graph of resonance frequency against log₁₀ (overlay thickness) shows three distinct regions corresponding to different overlay thickness values. Furthermore, using the theoretical curves the relative dielectric constant of the paste material at microwave frequencies is estimated, by curve fitting. The reported data are found to agree with the theoretical predictions for all regions.