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Run your analysis now →https://www.patsnap.com/resources/blog/rd-blog/conducted-emi-filter-design-patent-landscape/ · Patsnap · data cut-off 2026-07-31 · downloaded from the live page
Patent Landscape · Electromagnetic CompatibilityConducted EMI Filter Design Patents: Who Leads and Where the Filing Gaps Sit
- Concentrated but not locked up. the top five assignees hold 172 of 665 records (25.9%), and the top ten hold 237 (35.6%) — leaving a long tail of single- and few-filing entrants across the rest of the ranking.
- Magnetics and filter networks dominate class activity. H01F (inductors & transformers) and H03H (impedance networks & filters) each cover roughly a quarter to a third of the 665 records, ahead of power conversion (H02M) at 24.5%.
- Filing momentum is still rising through the last complete year. activity climbed from 14 in 2021 to 20 in 2024, a 43% increase over that span, even as the field's 2020 peak of 54 has not been matched since.
665
Published Records
26%
Top-5 Share of All Records
+43%
Filing Growth 2021→2024
US
Leading Jurisdiction
Filing growth compares 2021 (14 records) with 2024 (20) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 665 records in scope (CR5), not by the ranked leaders only.
Published byPatsnap Research··7 min readSourced from Patsnap Eureka
Overview
What this landscape covers
Conducted EMI filter design sits at the intersection of magnetics, power electronics and circuit layout: common mode chokes, Y-capacitor selection, insertion loss tuning and filter placement decisions that determine whether a power supply or converter passes conducted emissions testing. The 665 records in scope span 2015 through the 2026 data cut-off and were pulled using claim and abstract language tied to filter topology, insertion loss and leakage current limits rather than any single product category. Patent families, not raw document counts, are the more reliable unit here because continuation filings and multi-jurisdiction refiling can otherwise inflate a single invention's apparent footprint.
Filing activity is anchored in the United States, with the EPO, WIPO's PCT route, Germany and China each contributing a meaningful but smaller share of receiving-office activity. That distribution points to a field where protection is sought broadly but the core inventive filing still concentrates in a handful of jurisdictions.
Filing activity by year, 2017–2026
Source: Patsnap Eureka. Assignee ranking and totals. Derived from a Patsnap search on Conducted EMI Filter Design covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
The Numbers
Filing trends and technology composition
Two views of the same 665-record corpus: how filing volume has moved year over year, and how the underlying technology splits across IPC subclasses.
Filing trend, 2017–2026
Volume peaked at 54 records in 2020 and has not returned to that level since, but the most recent complete years show renewed growth: 2021's 14 records rose to 20 by 2024, a 43% increase. 2025 and 2026 figures will continue to fill in as publication catches up with filing, typically an 18-month lag, so the apparent tapering at the very end of the chart understates real activity.
Technology composition by IPC subclass
H01F (magnets, inductors and transformers) and H03H (impedance networks and filters) are the two largest classes, each covering more than a quarter of all 665 records, followed closely by H02M power conversion at 24.5%. Smaller but still substantial shares sit in H05K circuit assemblies, H04L and H04B transmission-related filings, H01R connectors, and a distinct A61N electrotherapy cluster reflecting implant-grade filter applications. Because records can carry multiple classes, these shares sum to well over 100% and should be read as overlap, not as a partition of the field.
Shares are the percentage of the 665 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Source: Patsnap Eureka. Filing trend and technology composition. Derived from a Patsnap search on Conducted EMI Filter Design covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.
Go deeper on Conducted EMI Filter Design with Eureka
This page is one run against one query. Ask Eureka your own question about conducted emi filter design and every answer comes back with the patent numbers behind it.
Try EurekaKey Patents
Representative and most-cited filings
Representative Filing
US20230178282A1 — Common mode choke and method of operation
TDK ELECTRONICS AG
A common mode choke with extended frequency range and improved reflection in mode conversion is specified. In this case, the common mode choke has a coil with three turns, where a coupling between a first turn and a second turn is different from a coupling between the second turn and an n-th turn, and so on.Filed by TDK Electronics AG, published 2023-06-08.
Most-cited records in this dataset
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6999818B2 | Inductor capacitor EMI filter for human implant applications | 328 |
| 2 | US6563816B1 | Virtual loop carrier system with gateway protocol mediation | 299 |
| 3 | US5257006A | Method and apparatus for power line communications | 252 |
| 4 | US5647767A | Electrical connector jack assembly for signal transmission | 251 |
| 5 | US5587884A | Electrical connector jack with encapsulated signal conditioning components | 204 |
| 6 | US6377227B1 | High efficiency feed network for antennas | 199 |
| 7 | US20090243756A1 | Shielded three-terminal flat-through EMI/energy dissipating filter | 178 |
| 8 | US6731627B1 | Virtual loop carrier system | 175 |
| 9 | US20170187472A1 | Magnetic Circuit for High Speed Automotive Ethernet Over UTP Channels | 154 |
| 10 | US5825259A | Electromagnetic interference isolator with common mode choke | 148 |
Citation counts reflect influence within the searched corpus and skew toward older filings; they are not a measure of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
Source: Patsnap Eureka. Citation counts and representative records. Derived from a Patsnap search on Conducted EMI Filter Design covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
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Reading the concentration and citation signals
The ranking and citation data point to a field with an established core of implant-grade and telecom-grade filter patents, alongside a still-open set of magnetics and layout claims.
Concentration
25.9%
of 665 records held by top 5
A moderate lead group, not a lock
The leader holds 49 records against a fifth-place figure of 20 and a tenth-place figure of 12 — a real gap at the top but a gentle slope beneath it, meaning most of the field sits with entities holding only a handful of filings each.
Based on the 100-company ranking returned by the dataset.
Citation influence
328 citations
highest-cited record
Oldest filings still anchor the citation graph
The most-cited record, an inductor-capacitor EMI filter for implant applications, and several 1990s connector and power-line communication patents dominate the citation counts, a pattern typical of a searched corpus where older foundational claims accumulate references over time.
Citation counts favour age, not current relevance.
Momentum
+43%
growth, 2021 to 2024
Renewed filing activity after the 2020 peak
After peaking at 54 records in 2020, filings dipped before climbing again through the most recent complete year, suggesting a second wave of investment in filter design distinct from the initial surge.
2025–2026 figures will rise as publication catches up.
Collaboration
10 pairs
co-assignee pairs identified
Collaboration is limited and mostly internal
The strongest co-filing pairs link a single assignee to individual named inventors rather than to other companies, indicating that cross-company joint filing is rare in this space.
Strongest pair recorded 3 joint filings.
Eureka AI Agent
Looking for what nobody has claimed yet?
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to conducted emi filter design, with the prior art for and against each one.
Source: Patsnap Eureka. Co-assignee relationships and derived observations. Derived from a Patsnap search on Conducted EMI Filter Design covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
Players
Who is filing, and where the room to move sits
The ranked leaders span magnetics specialists, implant-device makers and power semiconductor firms, but recent-year momentum has cooled across the names with the largest historical totals — a signal that the current wave of filing may be coming from outside the established leaders.
Leader
49 records
top-ranked assignee
A single clear leader by volume
The top-ranked assignee holds 49 of the 665 records in scope, well ahead of the fifth-place figure of 20, giving it the largest single claim on conducted EMI filter design art in this dataset.
Ranking covers 100 companies, counted in records.
Mid-field
12 records
tenth-place assignee
A gentle drop-off past the top ten
By tenth place, holdings fall to 12 records, and the top ten combined account for 237 records — 35.6% of the 665 in scope — leaving nearly two-thirds of the corpus spread across a long tail of smaller filers.
Top 10 combined = 35.6% of all records in scope.
Momentum
0 in latest year
for several historical leaders
Established names show flat recent activity
Several of the historically largest assignees, including firms with prior double-digit annual output, show zero filings in the latest tracked year, consistent with the broader 18-month publication lag rather than necessarily a real pullback.
Recency reads should be treated cautiously given publication lag.
Recent-year filing momentum by assignee
| Assignee | Recent year | YoY |
|---|---|---|
| Murata Manufacturing Co., Ltd. | 0 | — |
| Greatbatch Ltd. | 0 | — |
| International Rectifier Corp. | 0 | — |
| Toyota Industries Corp. | 0 | -100% |
| Telefonaktiebolaget LM Ericsson (publ) | 0 | — |
| Schaffner EMV AG | 0 | — |
| Linear Technology Holdings LLC | 0 | — |
| Bel Fuse Macao Commercial Offshore Ltd. | 0 | — |
Source: Patsnap Eureka. Assignee-level momentum. Derived from a Patsnap search on Conducted EMI Filter Design covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
What's Next
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, competitive tracking or claim drafting.
Run a freedom-to-operate check on choke coupling claims
Multi-turn common mode choke designs with non-uniform inter-turn coupling, as in the representative TDK filing, sit in an active claim area — a targeted search before committing to a similar topology is worth the time.
Explore in EurekaTrack momentum shifts among mid-tier filers
With established leaders showing flat recent output, the next wave of contested claims may come from the long tail rather than the historical top ten — worth a standing watch rather than a one-time search.
Set up monitoring in EurekaMap claim language around under-claimed sub-areas
Filter placement optimisation and adaptive saturation compensation show thinner filing density than the core magnetics classes, suggesting room for a first-mover claim if the underlying technical work is ready.
Draft claims in EurekaSource: Patsnap Eureka. Forward-looking reading of the same dataset. Derived from a Patsnap search on Conducted EMI Filter Design covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
FAQ
Common questions on conducted EMI filter design patents
The leading assignee in this 665-record dataset holds 49 records, ahead of a fifth-place assignee at 20 and a tenth-place assignee at 12. The top five assignees combined account for 172 records, or 25.9% of all records in scope, and the top ten account for 237, or 35.6%. That leaves close to two-thirds of the field spread across a long tail of smaller filers, so no single company controls the space outright.
Magnetics (IPC class H01F, covering inductors and transformers) and impedance networks and filters (H03H) are the two largest classes, each present in more than a quarter of the 665 records. Power conversion circuitry (H02M) follows closely at 24.5%. Because a single patent can be classified under several IPC codes, these shares overlap rather than summing to 100%, reflecting how tightly choke design, filter topology and power circuitry are bundled together in practice.
Filing volume peaked at 54 records in 2020 and has not returned to that level, but the most recent complete years show renewed growth: 2021's 14 records climbed to 20 by 2024, a 43% increase. Figures for 2025 and 2026 appear lower only because publication typically lags filing by around 18 months, so those years are still filling in and should not be read as a genuine slowdown.
US20230178282A1, filed by TDK Electronics AG and published 2023-06-08, describes a common mode choke with a multi-turn coil where the coupling between the first and second turns differs from the coupling between the second and subsequent turns. The design targets extended frequency range and improved reflection behaviour during mode conversion. Anyone designing a common mode choke with deliberately non-uniform inter-turn coupling for similar performance goals should review this filing before finalising a topology.
Relative to the dense core of magnetics and filter-network claims, areas such as filter placement optimisation for PCB layout, adaptive choke saturation compensation, and Y-capacitor leakage current limiting for medical isolation show thinner filing density in this dataset. That does not guarantee an easy path to a grant, but it does suggest less crowded prior art for a well-drafted first claim. A proper novelty search against the full record set is still the necessary next step before relying on this as a filing strategy.
Answers are grounded in the same dataset. Derived from a Patsnap search on Conducted EMI Filter Design covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish.Run this in Eureka MCP
Research Conducted EMI Filter Design in depth with Eureka
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company's registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.