Methods, computer readable media, and graphical user interfaces for analysis of frequency selective surfaces

• US 7,792,644 B2
• Filed: 11/13/2007
• Issued: 09/07/2010
• Est. Priority Date: 11/13/2007
• Status: Active Grant

• Current Assignee: Battelle Energy Alliance LLC (Battelle Memorial Institute)
• Original Assignee: Battelle Energy Alliance LLC (Battelle Memorial Institute)
• Inventors: Rohrbaugh, David T., Kotter, Dale K.
• Primary Examiner(s): Wachsman; Hal D
• Assistant Examiner(s): HENSON, MISCHITA L
• Application Number:
  US11/939,358
• Publication Number:
  US 20090125254A1
• Time in Patent Office: 1,029 Days
• Field of Search: 702/57, 702 64- 65, 343/756
• US Class Current: 702/22
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

A frequency selective surface (FSS) and associated methods for modeling, analyzing and designing the FSS are disclosed. The FSS includes a pattern of conductive material formed on a substrate to form an array of resonance elements. At least one aspect of the frequency selective surface is determined by defining a frequency range including multiple frequency values, determining a frequency dependent permittivity across the frequency range for the substrate, determining a frequency dependent conductivity across the frequency range for the conductive material, and analyzing the frequency selective surface using a method of moments analysis at each of the multiple frequency values for an incident electromagnetic energy impinging on the frequency selective surface. The frequency dependent permittivity and the frequency dependent conductivity are included in the method of moments analysis.

Claims

1. A method for analyzing a frequency selective surface wherein at least one act of the method is performed by a processing system, comprising:

defining a frequency range comprising a plurality of frequency values within the frequency range;

determining a frequency dependent permittivity for each of the plurality of frequency values across the frequency range for a substrate included in a frequency selective surface;

determining a frequency dependent conductivity for each of the plurality of frequency values across the frequency range for a conductive material included in the frequency selective surface;

analyzing the frequency selective surface using a method of moments analysis at each of the plurality of frequency values for an incident electromagnetic energy impinging on the frequency selective surface by including the frequency dependent permittivity and the frequency dependent conductivity in the method of moments analysis to develop a frequency response function;

defining a geometry of the frequency selective surface comprising the substrate and the conductive material disposed on the substrate to form an array of resonance elements; and

determining an emissivity of the frequency selective surface at each of the plurality of frequency values using the frequency dependent permittivity properties of the substrate and the frequency dependent conductivity properties of the conductive material.

2. The method of claim 1, wherein determining the frequency dependent permittivity across the frequency range for the substrate further comprises:

determining the frequency dependent permittivity for the substrate comprising a dielectric material selected from the group consisting of polyethylene, polyethylene derivatives, polypropylene, acrylic, fluoropolymer, polystyrene, polystyrene derivatives, polymethyl methacrylate, polyvinyl chloride, polyvinyl chloride derivatives, polyethylene terephthalate, polyimide, polyolefin, silicon, and gallium arsenide.

3. The method of claim 1, further comprising performing the analysis of the frequency selective surface for a parameter of interest at each of a plurality of parameter values to develop a plurality of corresponding frequency response functions for each parameter value of the plurality.

4. The method of claim 3, further comprising selecting the parameter of interest from the group consisting of angle of incidence for the incident electromagnetic energy, conductive material thickness, conductive material trace width, substrate thickness, resonance element size, resonance element periodicity, and spacing between resonance elements.

5. The method of claim 1, wherein analyzing the frequency selective surface further comprises including electro-optic properties of an overcoat disposed over the frequency selective surface structure and configured to emulate at least one environmental condition.

6. The method of claim 1, wherein:

the frequency selective surface includes at least two stacked layers of frequency selective surfaces wherein a layer of the at least two stacked layers includes at least one resonance element exhibiting a first geometry and a second layer of the at least two stacked layers includes at least one resonance element exhibiting a second geometry different from the first geometry; and

wherein analyzing the frequency selective surface further comprises analyzing the combination of the at least two stacked layers.

7. A method for analyzing a frequency selective surface wherein at least one act of the method is performed by a processing system, comprising:

defining a frequency range comprising a plurality of frequency values within the frequency range;

determining a frequency dependent permittivity for each of the plurality of frequency values across the frequency range for a substrate included in a frequency selective surface;

analyzing the frequency selective surface using a method of moments analysis at each of the plurality of frequency values for an incident electromagnetic energy impinging on the frequency selective surface by including the frequency dependent permittivity in the method of moments analysis to develop a frequency response function; and

analyzing the frequency response function to determine at least one filter response coefficient selected from the group consisting of major peaks, magnitude, trapezoidal integration of area under the response curve, ratios of user-specified regions of the plot, transient slope and response time of the filter response.

8. The method of claim 7, wherein determining the frequency dependent permittivity across the frequency range for the substrate further comprises:

determining the frequency dependent permittivity for the substrate comprising a dielectric material selected from the group consisting of polyethylene, polyethylene derivatives, polypropylene, acrylic, fluoropolymer, polystyrene, polystyrene derivatives, polymethyl methacrylate, polyvinyl chloride, polyvinyl chloride derivatives, polyethylene terephthalate, polyimide, polyolefin, silicon, and gallium arsenide.

9. The method of claim 7, further comprising performing the analysis of the frequency selective surface for a parameter of interest at each of a plurality of parameter values to develop a plurality of corresponding frequency response functions for each parameter value of the plurality.

10. The method of claim 9, further comprising selecting the parameter of interest from the group consisting of angle of incidence for the incident electromagnetic energy, conductive material thickness, conductive material trace width, substrate thickness, resonance element size, resonance element periodicity, and spacing between resonance elements.

11. The method of claim 7, wherein analyzing the frequency selective surface further comprises including electro-optic properties of an overcoat disposed over the frequency selective surface structure and configured to emulate at least one environmental condition.

12. The method of claim 7, wherein:

the frequency selective surface includes at least two stacked layers of frequency selective surfaces wherein a layer of the at least two stacked layers includes at least one resonance element exhibiting a first geometry and a second layer of the at least two stacked layers includes at least one resonance element exhibiting a second geometry different from the first geometry; and

wherein analyzing the frequency selective surface further comprises analyzing the combination of the at least two stacked layers.

13. A method for analyzing a frequency selective surface wherein at least one act of the method is performed by a processing system, comprising:

defining a frequency range comprising a plurality of frequency values within the frequency range;

determining a frequency dependent conductivity for each of the plurality of frequency values across the frequency range for a conductive material included in a frequency selective surface; and

analyzing the frequency selective surface using a method of moments analysis at each of the plurality of frequency values for an incident electromagnetic energy impinging on the frequency selective surface by including the frequency dependent conductivity in the method of moments analysis to develop a frequency response function.

14. The method of claim 13, wherein determining the frequency dependent conductivity across the frequency range for the conductive material further includes determining the frequency dependent conductivity for the conductive material in the range of 1.0×

10⁶ Ohms<sup>−

1</sup> cm<sup>−

1</sup> to 106.0×

10⁶ Ohms<sup>−

1</sup> cm<sup>−

1</sup>.

15. The method of claim 13, further comprising determining a frequency dependent permittivity for each of the plurality of frequency values across the frequency range for a substrate included in the frequency selective surface, and wherein the analyzing the frequency selective surface further comprises including the frequency dependent permittivity in the method of moments analysis at each of the plurality of frequency values.

16. The method of claim 13, further comprising:

defining a geometry of the frequency selective surface comprising a substrate and the conductive material disposed on the substrate to form an array of resonance elements; and

wherein determining an emissivity of the frequency selective surface at each of the plurality of frequency values responsive to the analyzing the frequency selective surface.

17. The method of claim 13, further comprising performing the analysis of the frequency selective surface for a parameter of interest at each of a plurality of parameter values to develop a plurality of corresponding frequency response functions for each parameter value of the plurality.

18. The method of claim 13, further comprising analyzing the frequency response function to determine at least one filter response coefficient selected from the group consisting of major peaks, magnitude, trapezoidal integration of area under the response curve, ratios of user-specified regions of the plot, transient slope and response time of the filter response.

19. A Graphical User Interface (GUI) for modeling, analyzing and designing frequency selective surfaces, comprising:

an interface element for defining a frequency range comprising a plurality of frequency values within the frequency range;

an element for accessing a frequency dependent permittivity for each of the plurality of frequency values across the frequency range for a substrate included in a frequency selective surface;

an element for accessing a frequency dependent conductivity for each of the plurality of frequency values across the frequency range for a conductive material included in the frequency selective surface; and

an element for controlling a method of moments analysis module to analyze, at each of the plurality of frequency values, the frequency selective surface for an incident electromagnetic energy impinging on the frequency selective surface by including the frequency dependent permittivity and the frequency dependent conductivity in the method of moments analysis.

20. The GUI of claim 19, further comprising:

an interface element for defining a geometry of the frequency selective surface comprising the substrate and the conductive material disposed on the substrate to form an array of resonance elements; and

an interface element for presenting an emissivity of the frequency selective surface at each of the plurality of frequency values responsive to the method of moments analysis.

21. The GUI of claim 19, wherein the element for controlling the method of moments analysis module further comprises performing the analysis of the frequency selective surface for a parameter of interest at each of a plurality of parameter values to develop a plurality of corresponding frequency response functions for each parameter value of the plurality.

22. A non-transitory computer readable media including computer executable instructions, which when executed on a processor perform acts, comprising:

defining a frequency range comprising a plurality of frequency values within the frequency range;

determining a frequency dependent permittivity for each of the plurality of frequency values across the frequency range for a substrate included in a frequency selective surface;

determining a frequency dependent conductivity for each of the plurality of frequency values across the frequency range for a conductive material included in a frequency selective surface; and

analyzing the frequency selective surface using a method of moments analysis at each of the plurality of frequency values for an incident electromagnetic energy impinging on the frequency selective surface by including the frequency dependent permittivity and the frequency dependent conductivity in the method of moments analysis to develop a frequency response function.

23. The computer readable media of claim 22, wherein the computer executable instructions further cause the processor to perform acts, comprising:

defining a geometry of the frequency selective surface comprising the substrate and the conductive material disposed on the substrate to form an array of resonance elements; and

determining an emissivity of the frequency selective surface at each of the plurality of frequency values responsive to the analysis of the frequency selective surface.

24. The computer readable media of claim 22, wherein the computer executable instructions further cause the processor to perform the analysis of the frequency selective surface for a parameter of interest at each of a plurality of parameter values to develop a plurality of corresponding frequency response functions for each parameter value of the plurality.

26. The apparatus of claim 22, wherein the substrate comprises a dielectric material selected from the group consisting of polyethylene, polypropylene, acrylic, fluoropolymer, polystyrene, polymethyl methacrylate, polyethylene terephthalate, polyimide, polyolefin, silicon, and gallium arsenide.

25. An apparatus, comprising:

a frequency selective surface comprising a pattern of conductive material formed on a substrate to form an array of resonance elements; and

wherein at least one aspect of the frequency selective surface is determined by;

defining a frequency range comprising a plurality of frequency values within the frequency range;

determining a frequency dependent permittivity for each of the plurality of frequency values across the frequency range for the substrate;

determining a frequency dependent conductivity for each of the plurality of frequency values across the frequency range for the conductive material; and

analyzing the frequency selective surface using a method of moments analysis at each of the plurality of frequency values for an incident electromagnetic energy impinging on the frequency selective surface by including the frequency dependent permittivity and the frequency dependent conductivity in the method of moments analysis to develop a frequency response function.

27. The apparatus of claim 25, wherein the conductive material is selected from the group consisting of manganese, gold, silver, copper, aluminum, platinum, nickel, iron, lead, tin.

28. The apparatus of claim 25, wherein each of the resonance elements comprises a geometry for the pattern of conductive material selected from the group consisting of square loops, circular loops, concentric loops, square spirals, circular spirals, slots, and crosses.