Patent ID: 11909107
Assignee: 3M INNOVATIVE PROPERTIES COMPANY
Field: Surface technology, coating (Chemistry)
Classification: CPC H  B | IPC B  H

Claim 0:
1. A gradient permittivity film comprising:
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
a second permittivity layer having a second effective layer relative permittivity (ε2) and a thickness (T2) 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:
ε1 is greater than ε2 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
       
      
     
    
   
  
 

εr1 is greater than εr2 for the frequency.