A Material Selection Method for High Frequency Connectors

Abstract

Manufacturers of a high-frequency connectors consider their electrical performance based on the type of material used, in particular by its relative dielectric constant and loss tangent. In addition, manufacturers have to consider mechanical and molding properties as well as the cost of the material. This paper focuses on developing an optimal method for selecting a high frequency connector material based on electrical, mechanical, and molding properties. This method relies on modified Ashby plots and current industry standards to obtain an optimal region where possible polymers are placed and thereby a practicing signal integrity engineer can choose an appropriate material for a given application. The modified Ashby plot involve the use of sigmoid functions to modify the electrical properties axis as well normalization of the mechanical properties axis, to generate an optimal region. To verify the above method, a material, satisfying the Ashby plot requirements, is chosen. This material is further electrically characterized using the coaxial airline technique up to a frequency range of 18 GHz. The broadband characterization process involves acquiring the scattering parameters from a vector network analyzer and calculating the electrical properties such as dielectric constant and loss tangent. This method allows the practicing signal integrity engineer to efficiently choose polymers for a variety of connectors used in high frequency consumer electronics application such as USB, HDMI, and Thunderbolt.