Quasi-TEM Characteristic Impedance of Micromachined CMOS Coplanar Waveguides

Published

May 5, 2000

Author(s)

Mehmet Ozgur, V. Milanovic, C. A. Zincke, Michael Gaitan, Mona E. Zaghloul

Abstract

Micromachined coplanar waveguides fabricated in CMOS technology consist of glass-encapsulated finite-thickness metal conductor strips, fully suspended by selective etching of the silicon substrate. Determination of the quasi-TEM mode characteristic impedance requires knowledge of the quasi-static capcitance of the complete structure, and the quasi-static capacitance of the equivalent air-line structure. In this paper, analytical results are derived for such structures based on conformal mapping transformations and partial capacitance approach. The analytical results and proposed approximations are verified by a finite-difference computational approach and by measurement results on various sample structures. The results are useful for solving general capacitance problems for finite-thickness planar transmission lines with multi-layer dielectric.

Citation

IEEE Transactions on Microwave Theory and Techniques

Pub Type

Journals

Keywords

Silicon micromachining, coplanar waveguide, quasi-static, quasi-TEM mode, characteristic impedance, effective permittivity

Citation

Ozgur, M. , Milanovic, V. , Zincke, C. , Gaitan, M. and Zaghloul, M. (2000), Quasi-TEM Characteristic Impedance of Micromachined CMOS Coplanar Waveguides, IEEE Transactions on Microwave Theory and Techniques (Accessed October 10, 2025)