Mitigating Electromagnetic Interference with Filtered Connectors
Spectrum Control
This white paper from Spectrum Control examines how EMI-filtered connectors address the growing challenge of electromagnetic interference in modern electronic systems across aerospace, defense, medical, and industrial applications. EMI impacts power integrity, signal integrity, signal-to-noise ratio, and regulatory compliance, and traditional board-mount filters consume valuable PCB space. The paper explains how parasitic effects — specifically equivalent series resistance (ESR) and equivalent series inductance (ESL) — limit the effectiveness of capacitors at high frequencies and must be carefully managed in filter design. Circular filtered connectors are presented as an efficient solution, with a single connector capable of replacing up to 128 discrete filters. Spectrum Control introduces a novel Pi-configurable design using planar capacitor arrays on configurable substrates, which delivers robust attenuation beyond 1 GHz while reducing delivery time to 12 weeks compared to 26+ weeks for fully custom solutions. EMC test data demonstrates the before-and-after effectiveness of these connectors in a flight system application.