A short-circuit transmission line method for PIM evaluation of metallic materials

Abstract

A short-circuit transmission line method for PIM evaluation of metallic materials is proposed in this paper. This method has no restriction of impedance matching at all, and is advantageously free from the low noise termination problem. This enables to treat arbitrarily-shaped samples as a point PIM source, and evaluate them in appropriate current density condition. In addition, the current anti-node of a standing wave located on a sample magnifies observed PIM property. These features improve the resolution and stability in low-level PIM measurement compared for the conventional method using terminated transmission line. Validity of the proposed method is confirmed by the experiments using wires and copper foils in 2 GHz. The sample is evaluated in the form of a shorting wire so that the current density on sample is estimated exactly. PIM characteristics of copper foils are also investigated, which indicates that small differences among the foils are detected clearly.