Passive Intermodulation at Contacts of Rough Conductors

TL;DR

This paper investigates the sources and mechanisms of passive intermodulation (PIM) at conductor contacts, emphasizing the role of surface roughness and nonlinearities, and advocates for advanced multiphysics models for better prediction.

Contribution

It provides a detailed analysis of PIM generation mechanisms at conductor joints and highlights the need for novel multiphysics modeling approaches.

Findings

Surface roughness significantly influences PIM generation.

Passive nonlinearities are interconnected across electrical, thermal, and mechanical domains.

Multiphysics models are essential for accurate PIM prediction.

Abstract

Passive intermodulation (PIM) is a niggling phenomenon that debilitates performance of modern communications and navigation systems. PIM products interfere with the information signals and cause their nonlinear distortion. The sources and basic mechanisms of PIM were studied in literature but PIM remains a serious problem of signal integrity. In this paper, the main sources and mechanisms of PIM generation by joints of good conductors are discussed. It is shown that the passive electrical, thermal and mechanical nonlinearities are intrinsically linked despite their distinctively different time scales. The roughness of the contact surfaces plays an important role in PIM generation by conductor joints. A review of the PIM phenomenology at contacts of the good conductors suggests that novel multiphysics models are necessary for the analysis and reliable prediction of PIM products generated by several concurrent nonlinearities of diverse physical nature.