Gradient permittivity film

Patent metadata

Field	Value
Publication number	US-11909107-B2
Application number	US-202318189780-A
Country	US
Kind code	B2
Filing date	Mar 24, 2023
Priority date	Apr 6, 2018
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A gradient permittivity film comprises (a) a first permittivity layer comprising a first continuous matrix of a first material having a first relative permittivity (εr1) and a second component having a second relative permittivity (εr2) dispersed in the first continuous matrix, the first permittivity layer having a first effective layer relative permittivity (ε1) and a thickness (T1); And (b) a second permittivity layer having a second effective layer relative permittivity (ε2) and a thickness (T2) disposed on the first permittivity layer. T1=0.8(t1) to 1.2(t1), wheret1=c4⁢f⁢ε1;⁢T2=0.8(t2)⁢to1.2(t2),where⁢t2=c4⁢f⁢ε2.

First claim

What is claimed is:

1. A gradient permittivity film comprising:
a first permittivity layer comprising a first continuous matrix of a first material having a first relative permittivity (ε r1 ) and a second component having a second relative permittivity (ε r2 ) dispersed in the first continuous matrix, the first permittivity layer having a first effective layer relative permittivity (ε 1 ) and a thickness (T 1 ); and
a second permittivity layer having a second effective layer relative permittivity (ε 2 ) and a thickness (T 2 ) disposed on the first permittivity layer;
wherein the gradient permittivity film has a haze greater than 50% or a transmission of visible light less than 50%; and
wherein:
ε 1 is greater than ε 2 by at least 10% for at least one frequency (f) within a frequency range between 20 GHz and 300 GHz,

ε
1

=

1.1

to
⁢

10

⁢

ε
2

=

1.11

to
⁢

10

⁢

T

1

=

0.8

(

t
1

)

⁢

to

1.2

(

t
1

)

,

where
⁢

t
1

=

c

2
⁢
f
⁢

ε
1

⁢

T
2

=

0
.
8

⁢

(

t
2

)

⁢

to

1.2

(

t
2

)

,

where
⁢

t
2

=

c

4
⁢
f
⁢

ε
2

ε r1 is greater than ε r2 for the frequency.

2. The gradient permittivity film of claim 1 wherein the second permittivity layer is an adhesive.

3. The gradient permittivity film of claim 2 wherein the second permittivity layer is an acrylic foam adhesive.

4. The gradient permittivity film of claim 1 wherein the second permittivity layer comprises a second continuous matrix of a fourth material having a fourth relative permittivity (ε r4 ) and a fifth component having a fifth relative permittivity (ε r5 ) dispersed in the second continuous matrix.

5. The gradient permittivity film of claim 1 wherein ε 1 is from 1.3 to 1.6.

6. The gradient permittivity film of claim 1 wherein ε 2 is from 1.9 to 2.6.

7. The gradient permittivity film of claim 1 wherein f is within a frequency range between 20 GHz and 120 GHz.

8. The gradient permittivity film of claim 7 wherein f is within a frequency range between 20 GHz and 100 GHz.

9. The gradient permittivity film of claim 8 wherein f is within a frequency range between 20 GHz and 81 GHz.

10. The gradient permittivity film of claim 9 wherein f is within a frequency range between 76 GHz and 81 GHz.

11. The gradient permittivity film of claim 9 wherein f is within a frequency range between 20 GHz and 30 GHz.

12. The gradient permittivity film of claim 1 wherein T 1 is from 1400 μm to 2400 μm and T 2 is from 400 μm to 900 μm.

13. The gradient permittivity film of claim 12 wherein T 1 is from 1600 μm to 1800 μm and T 2 is from 650 μm to 900 μm.

14. The gradient permittivity film of claim 1 wherein the second component is disposed within a third component having a third relative permittivity (ε r3 ) and ε r2 ≤ε r3 for the frequency f.

15. The gradient permittivity film of claim 14 wherein the third component is glass and the second component is air.

16. The gradient permittivity film of claim 1 wherein the first component includes a polymeric material.

17. The gradient permittivity film of claim 1 wherein the first continuous matrix is a nonwoven material.

18. The gradient permittivity film of claim 1 wherein the second component is air.

19. An assembly comprising the gradient permittivity film of claim 1 attached to a vehicle bumper fascia.

20. An assembly comprising the gradient permittivity film of claim 1 attached to an automobile radome.

Assignees

• 3M Innovative Properties Company

Inventors

• Salehi Mohsen
• Etzkorn Stephen J
• Kim Jaewon
• Sitter Brett J

Classifications

• H01Q1/424 Primary

  comprising a layer of expanded material · CPC title

• B32B5/022

  Non-woven fabric · CPC title

• B32B7/025

  Electric or magnetic properties · CPC title

• B32B7/12

  using interposed adhesives or interposed materials with bonding properties · CPC title

• B32B17/10

  of synthetic resin · CPC title