Dispersion characteristics of curved microstrip transmission lines

An empirical expression for the effective dielectric permittivity of curved microstrip transmission lines is derived. This expression is very general because it can also be used for rectangular microstrip lines by considering a rectangular line as a curved line of infinite radius of curvature. The closed-form expression for the frequency dependence of the effective dielectric permittivity of a rectangular microstrip line is compared with other available results. This expression for the frequency dependence of the effective dielectric permittivity of curved microstrip transmission lines is simple, accurate, and suitable for CAD implementation. The measured and computed results for various curved microstrip lines are compared, and excellent agreement between the two is obtained.<
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