Multi-layer magneto-dielectric material

Patent metadata

Field	Value
Publication number	US-11626228-B2
Application number	US-201715850466-A
Country	US
Kind code	B2
Filing date	Dec 21, 2017
Priority date	Dec 22, 2016
Publication date	Apr 11, 2023
Grant date	Apr 11, 2023

Abstract

A magneto-dielectric material operable between a minimum frequency and a maximum frequency, having: a plurality of layers that alternate between a dielectric material and a ferromagnetic material, lowermost and uppermost layers of the plurality of layers each being a dielectric material; each layer of the plurality of ferromagnetic material layers having a thickness equal to or greater than 1/15 th a skin depth of the respective ferromagnetic material at the maximum frequency, and equal to or less than ⅕ th the skin depth of the respective ferromagnetic material at the maximum frequency; each layer of the plurality of dielectric material layers having a thickness and a dielectric constant that provides a dielectric withstand voltage across the respective thickness of equal to or greater than 150 Volts peak and equal to or less than 1,500 Volts peak; and, the plurality of layers having an overall thickness equal to or less than one wavelength of the minimum frequency in the plurality of layers.

First claim

What is claimed is:

1. A magneto-dielectric material operable over an operating frequency range equal to or greater than a defined minimum frequency and equal to or less than a defined maximum frequency, the magneto-dielectric material comprising:
a plurality of layers in conforming direct contact with respective adjacent layers that alternate between a film of dielectric material and a film of ferromagnetic material forming a plurality of dielectric material layers in alternating arrangement with a plurality of ferromagnetic material layers, a lowermost layer and an uppermost layer of the plurality of layers each being a dielectric material;
each layer of the plurality of ferromagnetic material layers having a thickness equal to or greater than 1/15th a skin depth of the respective ferromagnetic material at the defined maximum frequency, and equal to or less than ⅕th the skin depth of the respective ferromagnetic material at the defined maximum frequency;
wherein the ferromagnetic material of each layer of the plurality of ferromagnetic material layers comprises a film of iron-nitride with continuous x-y plane permeability;
wherein the ferromagnetic material of each layer of the plurality of ferromagnetic material layers has a relative permeability of equal to or greater than 150 and equal to or less than 500;
each layer of the plurality of dielectric material layers having a thickness and a dielectric constant that provides a dielectric withstand voltage across the respective thickness of equal to or greater than 150 Volts peak and equal to or less than 1,500 Volts peak;
each layer of the plurality of dielectric material layers having a thickness greater than 0.1 micrometers and equal to or less than 10 micrometers: and
the plurality of layers having an overall thickness equal to or less than one wavelength of the defined minimum frequency in the plurality of layers.

2. The magneto-dielectric material of claim 1 , wherein:
at least one side of at least one layer of the plurality of dielectric material layers has an average surface roughness RMS value equal to or less than a defined maximum RMS value, wherein the defined maximum RMS value is equal to or less than 60 nanometers.

3. The magneto-dielectric material of claim 2 , wherein the defined maximum RMS value is 20 nanometers.

4. The magneto-dielectric material of claim 2 , wherein the defined maximum RMS value is 10 nanometers.

5. The magneto-dielectric material of claim 2 , wherein:
each side of the at least one layer of the plurality of dielectric material layers has an RMS value equal to or less than the defined maximum RMS value.

6. The magneto-dielectric material of claim 2 , wherein:
at least one side of each layer of the plurality of dielectric material layers has an RMS value equal to or less than the defined maximum RMS value.

7. The magneto-dielectric material of claim 2 , wherein:
each side of each layer of the plurality of dielectric material layers has an RMS value equal to or less than the defined maximum RMS value.

8. The magneto-dielectric material of claim 2 wherein the defined maximum RMS value is the root mean square average of the surface profile height deviations with respect to a mean line within an evaluation length according to measurement standard ASME B46.1.

9. The magneto-dielectric material of claim 2 wherein the defined maximum RMS value is determined by measurement in multiple linear directions over an entire surface area of the respective side of the respective layer of the plurality of dielectric material layers.

10. The magneto-dielectric material of claim 1 , wherein at least one interface between adjacent ones of the plurality of dielectric material layers and the plurality of ferromagnetic material layers has an average interface roughness RMS value equal to or less than a defined maximum RMS value, wherein the defined maximum RMS value is equal to or less than 60 nanometers.

11. The magneto-dielectric material of claim 10 , wherein the defined maximum RMS value is 20 nanometers.

12. The magneto-dielectric material of claim 10 , wherein the defined maximum RMS value is 10 nanometers.

13. The magneto-dielectric material of claim 10 , wherein each respective interface between adjacent ones of the plurality of dielectric material layers and the plurality of ferromagnetic material layers has an average interface roughness RMS value equal to or less than the defined maximum RMS value.

14. The magneto-dielectric material of claim 10 wherein the defined maximum RMS value is the root mean square average of the surface profile height deviations with respect to a mean line within an evaluation length according to measurement standard ASME B46.1.

15. The magneto-dielectric material of claim 10 wherein the defined maximum RMS value is determined by measurement in multiple linear directions over an entire respective interface area of the respective adjacent ones of the plurality of dielectric material layers and the plurality of ferromagnetic material layers.

16. The magneto-dielectric material of claim 1 operable at a resonant frequency fc, in Hertz (Hz), within the operating frequency range, wherein:
the plurality of layers are layered in a z-direction of an orthogonal x-y-z coordinate system, each layer of the plurality of layers being disposed substantially parallel to an x-y plane;
the plurality of layers has an initial relative magnetic permeability ui in the x-y plane; and
the plurality of layers has a Snoek's product ui times fc that is equal to or greater than 6×10 11 Hz and equal to or less than 8×10 11 Hz at an Ra surface roughness of at least one of the plurality of layers equal to about 7 nm.

17. The magneto-dielectric material of claim 1 operable at a resonant frequency fc, in Hertz (Hz), within the operating frequency range, wherein:
the plurality of layers are layered in a z-direction of an orthogonal x-y-z coordinate system, each layer of the plurality of layers being disposed substantially parallel to an x-y plane;
the plurality of layers has an initial relative magnetic permeability ui in the x-y plane; and
the plurality of layers has a Snoek's product ui times fc that is equal to or greater than 1.1×10 12 Hz and equal to or less than 1.8×10 12 Hz at an Ra surface roughness of at least one of the plurality of layers of less than 1 nm.

18. The magneto-dielectric material of claim 1 , wherein the plurality of layers are arranged parallel with an x-y plane in an orthogonal x-y-z coordinate system, the overall thickness of the plurality of layers is in the z-direction, and the wavelength in the plurality of layers is given by:
λ= c /[ f *sqrt(ε0*ε r*μ 0*μ r )];

where:
c is the speed of light in a vacuum in meters/second;
f is the defined minimum frequency in Hertz;
ε0 is the permittivity of a vacuum in Farads/meter;
εr is the relative permittivity of the plurality of layers in the z-direction;
μ0 is the permeability of a vacuum in Henrys/meter; and
μr is the relative permeability of the plurality of layers in the x-y plane.

19. The magneto-dielectric material of claim 1 , wherein:
each layer of the plurality of ferromagnetic material layers has a thickness equal to or greater than 100 nanometers and equal to or less than 200 nanometers.

Assignees

• Rogers Corp

Inventors

• Sprentall Karl E
• Shere Aniruddha J
• Chen Yajie
• Sethumadhavan Murali

Classifications

• H01Q9/0407 Primary

  Substantially flat resonant element parallel to ground plane, e.g. patch antenna (dipole H01Q9/285; monopole H01Q9/40) · CPC title

• H05K1/0373

  containing additives, e.g. fillers (H05K1/036 takes precedence) · CPC title

• H05K2201/086

  for inductive purposes, e.g. printed inductor with ferrite core · CPC title

• H01F10/265 Primary

  Magnetic multilayers non exchange-coupled (H01F10/32 takes precedence) · CPC title

• H01Q1/38 Primary

  formed by a conductive layer on an insulating support {(patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface  H01Q15/142)} · CPC title