Synthesis of metamaterial ferrites for RF applications using electromagnetic bandgap structures
AssigneeThe Penn State Research Foundation
InventorsDouglas H. Werner, Douglas J. Kern
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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.
Claims20
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.
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 μr′, the surface impedance having a surface reactance denoted XS1, wherein
- μ
- r
- ′
- =
- X
- S1
- η
- 0
-
- β
- 0
-
- d
- ,
- where η0 is the intrinsic impedance of free space, β0 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.
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.
Dependencies are inferred from the claim text.