Characterization of Single and Coupled Microstrip Lines Covered with Protective Dielectric Film

Kazuhiko ATSUKI
Keren LI

IEICE TRANSACTIONS on Electronics   Vol.E78-C    No.8    pp.1095-1099
Publication Date: 1995/08/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Microwave and Millimeter-Wave Technology)
microstrip line,  coupled microstrip line,  microwave integrated circuits,  multilayered medium structure,  protective dielectric film,  partial-boundary element method,  Green's function,  

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In this paper, we presented an analysis of single and coupled microstrip lines covered with protective dielectric film which is usually used in the microwave integrated circuits. The method employed in the characterization is called partial-boundary element method (p-BEM). The p-BEM provides an efficient means to the analysis of the structures with multilayered media or covered with protective dielectric film. The numerical results show that by changing the thickness of the protective dielectric films such as SiO2, Si and Polyimide covered on these lines on a GaAs substrate, the coupled microstrip lines vary within 10% on the characteristic impedance and within 25% on the effective dielectric constant for the odd mode of coupled microstrip line, respectively, in comparison with the structures without the protective dielectric film. In contrast, the single microstrip lines vary within 4% on the characteristic impedance and within 8% on the effective dielectric constant, respectively. The protective dielectric film affects the odd mode of the coupled lines more strongly than the even mode and the characteristics of the single microstrip lines.