On the design model of broadside‐coupled SSS line for microwave integrated circuits

A practical design model for the analysis of broadside‐coupled suspended‐substrate stripline is presented. The modified design expression of the shielded microstrip line is valid for a wide range of structural parameters and dielectric constants, that is, 1.0 ≤ ε r ≤ 140.0 for dielectric constant, 0.1 ≤ w/h ≤ 10.0 for strip width with an accuracy of <0.5%. This design expression is further extended for broadside‐coupled suspended‐substrate stripline. The proposed broadside‐coupled suspended‐substrate stripline (BCSSS) expressions are valid over a practical range of structural parameters and dielectric constants. The validity range of this expression for structural parameters is 1.0 ≤ ε r ≤ 16.0 for dielectric constant, 0.1 ≤ w/b ≤ 2.0 for strip width, and s/b ≤ 0.5 for substrate thickness. The average accuracy of the present expressions is <0.6% and <0.2% for the even‐ and odd‐mode effective dielectric constants, respectively, with maximum deviation less than 1.16% with respect to reference value. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 292–297, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20969