Filing in this space is led by a single assignee holding 21 of the 245 records in scope, with the fifth-ranked company at 12 and the tenth at 9. The top 5 assignees together account for 31.0% of all 245 records, and the top 10 for 50.6%, so there is real concentration at the top but it is not a monopoly — the ranked list runs to 83 companies, with a long tail of single- or few-filing entrants below the leaders. Anyone doing freedom-to-operate work should check both the leaders and the specific claim language, since concentration in filing count does not by itself tell you which claims are broad.

Package-level shielding covers the conformal coatings, sputtered layers, sidewall coverage and compartment shields applied directly onto or around a semiconductor package, rather than shielding built into a device housing or PCB enclosure. It gets claimed separately because the constraints are different: the shield has to survive reflow, maintain a ground path to the package substrate, and not add meaningful package height. That is why the dataset clusters so heavily in H01L (semiconductor devices, 48.6% of 245 records) and H05K (printed circuits, 38.0%) rather than in general antenna or enclosure classes.

The complete-year data shows filings falling from 20 in 2021 to 6 in 2024, a -70% decline, after a 2018 peak of 30. That is a real pullback in the most recent fully comparable years, but publication lags filing by roughly 18 months, so 2025 and 2026 figures in the raw trend are understated and should not be read as confirming a continued decline on their own. The honest read is that the field cooled from its 2018 high; whether it has stabilized or kept falling past 2024 is not yet visible in complete data.