Accurate closed-form solutions for fin-lines

Accurate closed-form expressions are derived for the theoretical prediction of equivalent dielectric constant, cutoff wavelength, and characteristic impedance of unilateral, bilateral and insulated fin-lines. The expressions developed on a physical basis are accurate to within ±0.6% and valid over the range of structural parameters 0 ≤ b/a ≤ 1, 1/32 ≤ d/b ≤ 1, and 1/32 ≤ s/a ≤ 1/4 (see Fig. 1).