A novel capacitance formula of the microstrip line using synthetic asymptote

Abstract

AbstractCapacitance formulas of the microstrip line are usually curve‐fitted from numerical solutions, resulting in multiple arbitrary coefficients and multiple equations. Such complexity in equations obscures their physical insight. By using the novel technique of synthetic asymptote, a single formula with just one arbitrary constant is obtained. In this paper, the formula for the line capacitance of arbitrary substrate dielectric constant, thickness, and strip width is investigated. Important parameters of the microstrip line, such as impedance and propagation, are inferred from this capacitance formula. The average errors of the calculated parameters are only 1%. The derived capacitance formula provides insight to enable us to distinguish between the parallel plate field and the fringe field and will find important application in microwave integrated circuit design. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 327–330, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10756