Electrically tunable surface impedance structure with suppressed backward wave
First Claim
1. A method of delaying the onset of a backward wave mode in a frequency selective surface having a two dimensional array of conductive patches and an RF ground plane, the two dimensional array of patches being interconnected by variable capacitors, the method comprising separating grounds associated with the variable capacitors from the RF ground plane and providing a separate conductive mesh structure as a ground for said variable capacitors.
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Abstract
A method of delaying the onset of a backward wave mode in a frequency selective surface having a two dimensional array of conductive patches or elements and an RF ground plane, the two dimensional array of patches or elements being interconnected by variable capacitors, the method comprising separating grounds associated with the variable capacitors from the RF ground plane and providing a separate conductive mesh structure or arrangement as a bias voltage ground for the variable capacitors. A tunable impedance surface comprises a RF ground plane; a plurality of patches or elements disposed in an array a distance from the ground plane; a capacitor arrangement for controllably varying capacitance between at least selected ones of adjacent patches or elements in the array; and a grounding mesh associated with the capacitor arrangement for providing a control voltage ground to capacitors in the capacitor arrangement, the grounding mesh being spaced from the RF ground plane by dielectric material.
198 Citations
17 Claims
- 1. A method of delaying the onset of a backward wave mode in a frequency selective surface having a two dimensional array of conductive patches and an RF ground plane, the two dimensional array of patches being interconnected by variable capacitors, the method comprising separating grounds associated with the variable capacitors from the RF ground plane and providing a separate conductive mesh structure as a ground for said variable capacitors.
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5. A tunable impedance surface comprising:
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(a) a RF ground plane; (b) a plurality of elements disposed in an array a distance from the ground plane; (c) a capacitor arrangement for controllably varying capacitance between at least selected ones of the elements in said array; and (d) a grounding mesh associated with said capacitor arrangement for providing a bias voltage ground to capacitors in said capacitor arrangement, the grounding mesh being spaced from the RF ground plane by dielectric material. - View Dependent Claims (6, 7, 8)
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9. A method of tuning a high impedance surface for reflecting a radio frequency signal comprising:
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arranging a plurality of generally spaced-apart conductive surfaces in an array disposed essentially parallel to and spaced from a conductive RF ground plane, and varying the capacitance between at least selected ones of adjacent conductive surfaces in to thereby tune the impedance of said high impedance surface using bias voltages, the bias voltages being referenced to a bias voltage ground supplied via a grounding mesh which is isolated from said RF ground plane by a layer of dielectric material. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A tunable impedance surface for reflecting a radio frequency beam, the tunable surface comprising:
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(a) a ground plane; (b) a plurality of elements disposed in an array a distance from the ground plane, the distance being less than a wavelength of the radio frequency beam; (c) a capacitor arrangement for controllably varying the impedance along said array; and (d) means for suppressing a formation of a backward wave by said tunable impedance surface.
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16. A tunable impedance surface comprising:
- (a) a ground plane;
(b) a plurality of discreet elements disposed in a two-dimensional array a distance from the ground plane; and
(c) a plurality of capacitors coupling neighboring ones of said elements in said two dimensional array for controllably varying capacitive coupling between said neighboring ones of said elements in said two-dimensional array while at the same time suppressing a formation of a backward wave by said tunable impedance surface. - View Dependent Claims (17)
- (a) a ground plane;
Specification