Multi-resonant, high-impedance electromagnetic surfaces

• US 20030122729A1
• Filed: 12/23/2002
• Published: 07/03/2003
• Est. Priority Date: 10/04/2000
• Status: Active Grant

• Current Assignee: Wemtec Inc.
• Original Assignee: E-Tenna Corporation
• Inventors: McKinzie, William E. III, Diaz, Rodolfo E.
• Granted Patent: US 6,774,867 B2
• Time in Patent Office: Days
• US Class Current: 343/909
• CPC Class Codes: H01Q 15/008 said selective devices having Sievenpipers' mushroom elements
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 9/0442 with particular tuning means

Abstract

An artificial magnetic conductor is resonant at multiple resonance frequencies. The artificial magnetic conductor is characterized by an effective media model which includes a first layer and a second layer. Each layer has a layer tensor permittivity and a layer tensor permeability having non-zero elements on the main tensor diagonal only.

Claims

1. An artificial magnetic conductor (AMC) resonant with a substantially zero degree reflection phase over at least two resonant frequency bands, the artificial magnetic conductor comprising a frequency selective surface having a plurality of Lorentz resonances in transverse permittivity at independent, non-harmonically related, predetermined frequencies different from the resonant frequency bands.

2. The AMC of claim 1 further comprising:

a spacer layer including an array of metal posts extending through the spacer layer, the frequency selective surface being disposed on the spacer layer.

3. The AMC of claim 2 further comprising:

a conductive ground plane adjacent the spacer layer and electrically contacting posts of the array of metal posts.

4. The AMC of claim 1 wherein the frequency selective surface comprises a plurality of conductive layers.

5. The AMC of claim 1 wherein the frequency selective surface has a transverse permittivity ∈

_1t defined by

6. The AMC of claim 5 wherein the frequency selective surface has a normal permeability μ

_1z defined by