H01F 21/08
By varying the permeability of the core
Official title: by varying the permeability of the core, e.g. by varying magnetic bias
H01F21/08 (By varying the permeability of the core) appears on 79 US grants and 65 published applications in this corpus.
Search patents in H01F- Granted patents
- 79
- Published applications
- 65
- Assignees
- 77
- Inventors
- 173
- Latest grant
- 25 Aug 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 1 | 0 |
| 1978 | 1 | 0 |
| 1979 | 0 | 0 |
| 1980 | 1 | 0 |
| 1981 | 2 | 0 |
| 1982 | 0 | 0 |
| 1983 | 3 | 0 |
| 1984 | 0 | 0 |
| 1985 | 3 | 0 |
| 1986 | 2 | 0 |
| 1987 | 2 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 2 | 0 |
| 1993 | 0 | 0 |
| 1994 | 0 | 0 |
| 1995 | 2 | 0 |
| 1996 | 1 | 0 |
| 1997 | 1 | 0 |
| 1998 | 1 | 0 |
| 1999 | 1 | 0 |
| 2000 | 0 | 0 |
| 2001 | 1 | 0 |
| 2002 | 1 | 2 |
| 2003 | 1 | 1 |
| 2004 | 3 | 2 |
| 2005 | 0 | 1 |
| 2006 | 0 | 2 |
| 2007 | 1 | 2 |
| 2008 | 4 | 3 |
| 2009 | 2 | 4 |
| 2010 | 3 | 1 |
| 2011 | 3 | 6 |
| 2012 | 2 | 2 |
| 2013 | 2 | 1 |
| 2014 | 1 | 5 |
| 2015 | 2 | 0 |
| 2016 | 2 | 5 |
| 2017 | 4 | 6 |
| 2018 | 5 | 7 |
| 2019 | 6 | 4 |
| 2020 | 2 | 2 |
| 2021 | 3 | 1 |
| 2022 | 2 | 0 |
| 2023 | 2 | 3 |
| 2024 | 2 | 2 |
| 2025 | 0 | 3 |
| 2026 | 1 | 0 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Tunable integrated voltage regulator25 Aug 2026US 12,719,362 B2APPLIED Materials.Inc.
- Variable inductor for plasma generator10 Sep 2024US 12,087,546 B2Advanced Energy Industries, Inc.
- Reactor25 Jun 2024US 12,020,840 B2Kyosan Electric Mfg. Co., Ltd.
- Chip-scale resonant gyrator for passive non-reciprocal devices4 Jul 2023US 11,695,382 B2The Board of Trustees of the University of Illinois
- Dually electrically tunable 3-D compact RF phase shifter28 Feb 2023US 11,594,797 B2Universtiy of South Carolina
- Variable inductor and control system for the variable inductor2 Oct 2025US 2025/0308767 A1
- Inductive link coil de-tuning compensation and control2 Oct 2025US 2025/0309698 A1Alfred E. Mann Foundation for Scientific Research
- System for parametric resonant varying inductance13 Mar 2025US 2025/0087400 A1Elan Research - 9456-4424 QuéBec Inc.
- Thin film inductor element and thin film variable inductor element2 May 2024US 2024/0145147 A1Japan Atomic Energy Agency
- Pulsed power circuits using hybrid non-linear magnetic materials and inductors incorporating the same1 Feb 2024US 2024/0039234 A1Cymer, Inc.
Most cited
By later US patents
- Inductive structures for semiconductor integrated circuits217US 5,095,357 AMitsubishi Denki Kabushiki Kaisha · 1992
- Resonant converter with controlled inductor145US 5,684,678 ADelco Electronics Corporation · 1997
- Orthogonal-field electrically variable magnetic device79US 5,534,837 ARockwell International Corporation · 1996
- Self isolating high frequency saturable reactor67US 5,770,982 ASematech, Inc. · 1998
- Regulating transformer with magnetic shunt60US 4,206,434 A1980