The finding

According to a working paper posted on SSRN by Yunan Han, Aqiao Jin, and Qiang Cui, conventional shielding-effectiveness (SE) test setups for board-level shield (BLS) gaskets struggle to keep pace with the higher operating frequencies and denser packaging now common on RF/mmWave PCBs. The authors propose a compact cavity-to-cavity test fixture: two symmetrical metal cavities, each roughly 30 mm x 15 mm x 3 mm, sit side by side and bond to a ground plane so the gasket under test is the only electrical path between them, mimicking how a gasket seals adjoining compartments inside a real board-level shield. Monopole probe pins are inserted on opposite sides of the two cavities, and SE is derived from the scattering parameters (S-parameters) measured between those probes. The authors report this setup extends usable SE characterization from 10 GHz up to 40 GHz, a band where many legacy gasket fixtures lose accuracy or become impractical to build. The method is positioned as more representative of actual multi-cavity BLS layouts than single-aperture or waveguide-based gasket tests typically used at lower frequencies.

Why it matters for RF/EMC design

Real multi-cavity board-level shields leak mainly through the gasket seam between adjacent compartments, not through a single aperture, so a cavity-to-cavity number is a better proxy for in-system performance than a single-cell SE test. A gasket rated across 10-40 GHz lets engineers catch materials that hold up fine at sub-6 GHz but degrade at mmWave seam gaps before committing to compression force, seam geometry, or gasket material on a fine-pitch RF partition. That earlier signal can save a chamber-test iteration on 5G/mmWave module designs where multiple shielded cavities sit close together on one board.

→ Read the original at SSRN

Source: Yunan Han, Aqiao Jin, Qiang Cui, "Shielding Effectiveness Measurement of Board-level Shields with Gaskets Using a Cavity-to-Cavity Testing Method", SSRN.