Cavity resonance reduction and/or shielding structures including frequency selective surfaces
View Patent ↗According to various aspects, exemplary embodiments include one or more frequency selective surfaces, which may be used for attenuating, reflecting, and/or redirecting electromagnetic signals. Also disclosed are methods of using one or more frequency selective surfaces for attenuating, reflecting, and/or redirecting electromagnetic signals.
1. A structure comprising a frequency selective surface including a plurality of electrically-conductive members and a plurality of electromagnetic energy absorptive members each coupled to a corresponding one of the electrically-conductive members, whereby the frequency selective surface is operable for attenuating electromagnetic signals within a cavity of a closed structure when the frequency selective surface is positioned within the cavity to thereby reduce cavity resonance and/or electromagnetic energy propagation within the cavity.
2. The structure of claim 1 , wherein:
the electrically-conductive members comprise electrically-conductive rings; and
the electromagnetic energy absorptive members comprise electromagnetic energy absorptive rings having a shape complementary in shape to the electrically-conductive rings.
3. The structure of claim 2 , wherein the electromagnetic energy absorptive members comprise magnetically loaded elastomer material adhered to the electrically-conductive rings.
4. The structure of claim 2 , wherein the electrically-conductive rings have an outer diameter within a range from 9 millimeters to 9.5 millimeters and an inner diameter within a range of 7 millimeters to 7.5 millimeters, such that the frequency selective surface is operable for reflecting, blocking, redirecting, and/or absorbing energy having a frequency of about 10.3 Gigahertz.
5. The structure of claim 1 , wherein:
the electromagnetic energy absorptive members are each adhered to a top surface of the corresponding one of the electrically-conductive members; and
the electrically-conductive members are coupled to and/or supported by a dielectric.
6. The structure of claim 1 , wherein:
the electrically-conductive members comprise metal rings; and
the electromagnetic energy absorptive members comprise electromagnetic energy absorptive rings adhered to the metal rings.
7. The structure of claim 1 , wherein:
the electrically-conductive members comprise aluminum rings; and
the electromagnetic energy absorptive members comprise magnetically loaded, silicone rubber material that is electrically non-conductive and that is complementary in shape to the aluminum rings.
8. The structure of claim 1 , wherein the frequency selective surface comprises dielectric members connected to and/or extending between the electrically-conductive members such that the electrically-conductive members are at spaced apart locations from each other in a pattern.
9. The structure of claim 1 , wherein the electrically-conductive members are tuned to resonate at one or more frequencies including a frequency of about 10.3 Gigahertz such that the frequency selective surface is operable for reflecting, blocking, redirecting, and/or absorbing energy having a frequency of about 10.3 Gigahertz to thereby reduce cavity resonance.
10. The structure of claim 1 , wherein:
the electrically-conductive members are configured to resonate at one or more frequencies such that the frequency selective surface is operable for reflecting, blocking, redirecting, and/or absorbing energy at the one or more frequencies; and/or
the frequency selective surface is configured to be operable for reducing cavity resonance and for reducing electromagnetic energy propagation within the cavity.
11. The structure of claim 1 , wherein:
the frequency selective surface comprises a dielectric substrate to which are coupled the electrically-conductive members and/or the electromagnetic energy absorptive members; and
the dielectric substrate is foam, flexible, and/or conformable to a mating surface.
12. A cavity resonance reduction and/or shielding structure comprising a frequency selective surface including:
a plurality of electrically-conductive members configured to resonate at one or more bandstop frequencies; and
a plurality of electromagnetic energy absorptive members each coupled to a corresponding one of the electrically-conductive members;
whereby the frequency selective surface is operable for attenuating electromagnetic signals at the one or more bandstop frequencies within a cavity of a closed structure when the frequency selective surface is positioned within the cavity.
13. The structure of claim 12 , wherein:
the electrically-conductive members comprise electrically-conductive rings; and
the electromagnetic energy absorptive members comprise electromagnetic energy absorptive rings having a shape complementary in shape to the electrically-conductive rings.
14. The structure of claim 12 , wherein the frequency selective surface is configured to be operable for reducing cavity resonance and for reducing electromagnetic energy propagation within the cavity; and
wherein the electromagnetic energy absorptive members are each coupled to a top surface of the corresponding one of the electrically-conductive members.
15. The structure of claim 12 , wherein:
the electrically-conductive members comprise aluminum rings; and
the electromagnetic energy absorptive members comprise magnetically loaded, silicone rubber material that is electrically non-conductive and that is complementary in shape to the aluminum rings.
16. The structure of claim 12 , wherein the electrically-conductive members and/or the electromagnetic energy absorptive members are coupled to and/or supported by a dielectric that is foam, flexible, and/or conformable to a mating surface.
17. The structure of claim 12 , wherein the frequency selective surface comprises dielectric members connected to and/or extending between the electrically-conductive members such that the electrically-conductive members are at spaced apart locations from each other in a pattern.
18. A method comprising positioning a frequency selective surface within a cavity of a closed structure such that electrically-conductive members and electromagnetic energy absorptive members of the frequency selective surface are operable for attenuating electromagnetic signals within the cavity, to thereby reduce cavity resonance and/or electromagnetic energy propagation within the cavity, wherein the electromagnetic energy absorptive members are each coupled to a corresponding one of the electrically-conductive members.
19. The method of claim 18 , wherein:
the electrically-conductive members configured to resonate at one or more bandstop frequencies;
and
the frequency selective surface is operable for attenuating electromagnetic signals within the cavity at the one or more bandstop frequencies.
20. The method of claim 18 , wherein:
the electrically-conductive members comprise electrically-conductive rings;
the electromagnetic energy absorptive members comprise electromagnetic energy absorptive rings having a shape complementary in shape to the electrically-conductive rings;
the electrically-conductive members and/or the electromagnetic energy absorptive members are coupled to and/or supported by a dielectric that is foam, flexible, and/or conformable to a mating surface; and
the frequency selective surface reduces cavity resonance and electromagnetic energy propagation within the cavity.