The Proportioning of Shielded Circuits for Minimum High-Frequency Attenuation

Abstract

For given conditions of design there exists an optimum proportioning or configuration which makes the high-frequency attenuation of a given type of individually shielded circuit a minimum. Determination is made of such optimum proportioning for a wide variety of types of individually shielded circuits including several novel types designed to make the high-frequency attenuation low in comparison with the cross-sectional area occupied by the circuit, and the attenuation of different types is compared. The following topics and specific circuit structures are considered: Coaxial Circuits — Basic Coaxial Circuit; Effect of Dielectric; Effect of Frequency on Optimum Ratio; Thin Walls; Stranded Conductors; Optimum Proportioning as a Function of Conductor Resistance. Balanced Shielded Circuits — Shielded Pair (Cylindrical Conductors and Shield) — Condition for Minimum Attenuation, Condition for Maximum Characteristic Impedance, Effect of Dielectric, Effect of Frequency; Pair in Space; Shielded Stranded Pair; Pair with Shield Return; Double Coaxial Circuit; Shielded Pair (Round Conductors and Oval Shield); Shielded Pair (Quasi-Elliptical Conductors); Shielded Quad.