	US 11,985,805 B2
	Thermally conductive electromagnetically absorptive material
Zhonghua Lu, Woodbury, MN (US); Badri Veeraraghavan, Woodbury, MN (US); Joel S. Peiffer, Maplewood, MN (US); Jeffrey A. Tostenrude, Leander, TX (US); Jaewon Kim, Woodbury, MN (US); Zulfiqar A. Khan, Woodbury, MN (US); and Jennifer J. Sokol, Mahtomedi, MN (US)
Assigned to 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
Appl. No. 17/910,543
Filed by 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
PCT Filed Mar. 23, 2021, PCT No. PCT/IB2021/052413 § 371(c)(1), (2) Date Sep. 9, 2022, PCT Pub. No. WO2021/198849, PCT Pub. Date Oct. 7, 2021.
Claims priority of provisional application 63/002,399, filed on Mar. 31, 2020.
Prior Publication US 2023/0119856 A1, Apr. 20, 2023
Int. Cl. H01Q 1/52 (2006.01); H01Q 1/02 (2006.01); H05K 9/00 (2006.01)

CPC H05K 9/0083 (2013.01) [H01Q 1/02 (2013.01); H01Q 1/526 (2013.01)]

6 Claims

1. A thermally conductive electromagnetically absorbing material comprising a plurality of particles dispersed in a binder, the plurality of particles comprising all particles dispersed in the binder for increasing electromagnetic absorption or thermal conductivity of the material, the plurality of particles consisting of a plurality of first particles having a first Dv50 size a1 and a plurality of second particles having a second Dv50 size a2, a1/a2≥1.5, the first particles comprising at most 1% of a total number of the first and second particles and being more electromagnetically absorbing than the second particles, such that the material has a thermal conductivity of at least 2 W/(m-K) along at least one direction, and for an at least one frequency in a frequency range from about 20 GHz to about 120 GHz, the material:

has a relative real permittivity of less than about 10; and

attenuates a substantially normally incident radiation having the at least one frequency by at least 5 dB/mm.