US7256753B2
Expired / Lapsed
US
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Synthesis of metamaterial ferrites for RF applications using electromagnetic bandgap structures
Assignee: Penn State Research Foundation
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Filing: 2004-01-12
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Granted: 2007-08-14
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Expires: 2024-01-12
Abstract
Abstract By configuring a high impedance frequency selective surface (HZ-FSS) structure for the appropriate values of surface impedance (surface resistance and surface reactance), a high frequency artificial ferrite metamaterial can be synthesized with almost any desired value of real and imaginary permeability. Materials with these properties have not previously been physically realizable at frequencies above 1 GHz.
Inventors
- 👤 Douglas H. Werner
- 👤 Douglas J. Kern
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:35
CPC Classifications
H; H01; H01Q; H01Q15/00; H01Q15/0006; H01Q15/0086
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
110 words
A method of designing a metamaterial structure having a required permeability at a predetermined frequency, the metamaterial structure including a frequency selective surface located proximate to an electrically conductive layer, the method comprising: relating the required permeability to a required surface impedance of the metamaterial structure at the predetermined frequency, the required permeability being equal to the required surface impedance divided by an intrinsic impedance of free space, a propagation constant of free space, and a thickness d of an equivalent electrical conductor backed magnetic film having the required permeability; and configuring the metamaterial structure so as to obtain the required surface impedance, the apparatus thereby having the required permeability.
Claim 2
Independent Claim
110 words
A method of designing a metamaterial structure having a required permeability at a predetermined frequency, the metamaterial structure including a frequency selective surface located proximate to an electrically conductive layer, the method comprising: relating the required permeability to a required surface impedance of the metamaterial structure at the predetermined frequency, the required permeability being equal to the required surface impedance divided by an intrinsic impedance of free space, a propagation constant of free space, and a thickness d of an equivalent electrical conductor backed magnetic film having the required permeability; and configuring the metamaterial structure so as to obtain the required surface impedance, the apparatus thereby having the required permeability.
Claim 3
Dependent Claim
80 words
The method of claim 1 , wherein the required permeability includes a required real permeability denoted μ r ′, the required surface impedance includes a required surface reactance denoted X S1 , the required real permeability being related to the required surface reactance using the equation μ r ′ = X S1 η 0 β 0 d , where η 0 is the intrinsic impedance of free space, and β 0 is the propagation constant of free space.
Claim 4
Dependent Claim
79 words
The method of claim 1 , wherein the required permeability includes a required imaginary permeability denoted μ r ″, the required surface impedance includes a required surface resistance denoted R S1 , the required imaginary permeability being related to the required surface resistance by the equation μ r ″ = R S1 η 0 β 0 d where η 0 is the intrinsic impedance of free space, and β 0 is the propagation constant of free space.
Claim 5
Dependent Claim
35 words
The method of claim 1 , wherein configuring the metamaterial structure so as to obtain the required surface impedance includes selecting the frequency selective surface to have a resonance frequency proximate to the predetermined frequency.
Claim 6
Dependent Claim
29 words
The method of claim 1 , wherein configuring the metamaterial structure so as to obtain the required surface impedance includes optimizing the frequency selective surface using an optimization algorithm.
Claim 7
Dependent Claim
14 words
The method of claim 5 , wherein the optimization algorithm is a genetic algorithm.
Claim 8
Dependent Claim
56 words
The method of claim 1 , wherein the frequency selective surface is disposed on a First side of the a dielectric substrate, and the electrically conductive layer is disposed on a second side of the dielectric substrate, the dielectric substrate having a dielectric thickness substantially less than the wavelength of electromagnetic radiation at the predetermined frequency.
Claim 9
Dependent Claim
15 words
An electromagnetic device including the metamaterial structure designed by the method of claim 1 .
Claim 10
Independent Claim
144 words
A method of designing a metamaterial structure having a permeability property of a ferrite film supported on a conducting ground plane, the metamaterial structure including a high impedance frequency selective surface, the method comprising: specifying a required permeability of the metamaterial structure; and relating the required permeability of the metamaterial structure to a surface impedance of the metamaterial structure, the required permeability having a required real component of permeability denoted μ r ′, the surface impedance having a surface reactance denoted X S1 , wherein μ r ′ = X S1 η 0 β 0 d , where η 0 is the intrinsic impedance of free space, β 0 is the propagation constant of free space, and d is the thickness of the ferrite film, the value of surface reactance being chosen so as to provide the required real component of permeability.
Claim 11
Independent Claim
144 words
A method of designing a metamaterial structure having a permeability property of a ferrite film supported on a conducting ground plane, the metamaterial structure including a high impedance frequency selective surface, the method comprising: specifying a required permeability of the metamaterial structure; and relating the required permeability of the metamaterial structure to a surface impedance of the metamaterial structure, the required permeability having a required real component of permeability denoted μ r ′, the surface impedance having a surface reactance denoted X S1 , wherein μ r ′ = X S1 η 0 β 0 d , where η 0 is the intrinsic impedance of free space, β 0 is the propagation constant of free space, and d is the thickness of the ferrite film, the value of surface reactance being chosen so as to provide the required real component of permeability.
Claim 12
Dependent Claim
60 words
The method of claim 9 , wherein the required permeability further includes a required imaginary component μ r ″, the required surface impedance having a surface resistance R S1 , wherein μ r ″ = R S1 η 0 β 0 d the value of surface resistance being chosen so as to provide the imaginary component of permeability.
Claim 13
Dependent Claim
33 words
The method of claim 9 , wherein the value of surface reactance is chosen using electromagnetic modeling of the metamaterial structure, the metamaterial structure being configured to provide the value of surface reactance.
Claim 14
Dependent Claim
26 words
The method of claim 11 , wherein an optimization algorithm is used to configure the metamaterial structure so as to provide the value of surface reactance.
Claim 15
Dependent Claim
14 words
The method of claim 12 , wherein the optimization algorithm is a genetic algorithm.
Claim 16
Dependent Claim
15 words
The method of claim 9 , wherein the required real component of permeability is negative.
Claim 17
Dependent Claim
125 words
A structure providing a required permeability at an operating frequency, the structure comprising: a dielectric substrate, having a first side and a second side, and having a dielectric thickness and a dielectric constant; an electrically conducting layer disposed on the first side of the dielectric substrate; and a frequency selective surface disposed on the second side of the dielectric substrate, the structure having a surface impedance, wherein the surface impedance of the structure at the operating frequency is selected so as to provide the required permeability, the required permeability being equal to the surface impedance divided by an intrinsic impedance of free space, a propagation constant of free space, and a thickness d of an equivalent electrical conductor backed magnetic film having the required permeability.
Claim 18
Dependent Claim
125 words
A structure providing a required permeability at an operating frequency, the structure comprising: a dielectric substrate, having a first side and a second side, and having a dielectric thickness and a dielectric constant; an electrically conducting layer disposed on the first side of the dielectric substrate; and a frequency selective surface disposed on the second side of the dielectric substrate, the structure having a surface impedance, wherein the surface impedance of the structure at the operating frequency is selected so as to provide the required permeability, the required permeability being equal to the surface impedance divided by an intrinsic impedance of free space, a propagation constant of free space, and a thickness d of an equivalent electrical conductor backed magnetic film having the required permeability.
Claim 19
Dependent Claim
18 words
The structure of claim 15 , wherein the frequency selective surface includes a two-dimensional array of conducting elements.
Claim 20
Dependent Claim
31 words
The structure of claim 16 , wherein the structure has the permeability properties of a ferrite film backed by a perfect electrical conductor, the operating frequency being greater than 1 GHz.
Claim 21
Dependent Claim
13 words
The structure of claim 15 , wherein the structure is an electromagnetic absorber.
Claim 22
Dependent Claim
9 words
An antenna including the structure of claim 15 .
Claim 23
Dependent Claim
10 words
A microwave device including the structure of claim 15 .
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