Projected artificial magnetic mirror
View Patent ↗A projected artificial magnetic mirror (PAMM) includes conductive coils, a metal backing, and a dielectric material. The conductive coils are arranged in an array on a first layer of a substrate and the metal backing is on a second layer of the substrate. The dielectric material is between the first and second layers of the substrate. The conductive coils are electrically coupled to the metal backing to form an inductive-capacitive network that, for a a selected frequency band, substantially reduces surface waves along a PAMM surface, the PAMM surface residing within the substrate or above the substrate. The PAMM surface may be substantially adjacent or coexistent with the first layer.
1. A projected artificial magnetic mirror (PAMM) comprises:
a plurality of conductive spiral coils arranged in an array on a first layer of a substrate;
a metal backing on a second layer of the substrate;
a dielectric material between the first and second layers of the substrate, wherein the plurality of conductive spiral coils is electrically coupled to the metal backing to form an inductive-capacitive network that, for a given frequency band, substantially reduces surface waves along an artificial magnetic conductor having a shape determined, at least in part, by the arrangement of the plurality of conductive spiral coils; and
an antenna element on a third layer of the substrate that is constructed to service communications in the given frequency band, the first layer of the substrate between the second layer and the third layer, and the first layer separated from the third layer by other dielectric material, wherein the artificial magnetic conductor and the antenna element operate to form an effective dish antenna.
2. The PAMM of claim 1 , wherein the coupling between a conductive spiral coil of the plurality of conductive spiral coils and the metal backing comprises at least one of:
a via electrical connection; and
a capacitive coupling.
3. The PAMM of claim 1 , wherein the given frequency band corresponds to Near Field Communications (NFC).
4. The PAMM of claim 1 , wherein a conductive spiral coil of the plurality of conductive spiral coils comprises:
a shape that includes at least one of be circular, square, rectangular, hexagon, octagon, and elliptical; and
a pattern that includes at least one of interconnecting branches, an n th order Peano curve, and an n th order Hilbert curve.
5. The PAMM of claim 1 further comprises:
a first conductive spiral coil of the plurality of conductive spiral coils has a first size and a first shape; and
a second conductive spiral coil of the plurality of conductive spiral coils has a second size and a second shape.
6. The PAMM of claim 1 , wherein a conductive spiral coil of the plurality of conductive spiral coils comprises:
a plurality of metal patches; and
a plurality of switching elements such that at least one of size, shape, and pattern of the conductive spiral coil is configurable.
7. The PAMM of claim 1 , wherein the artificial magnetic conductor is substantially non-planar and has a focal point, the antenna element positioned within the focal point.
8. The PAMM of claim 1 , wherein a conductive spiral coil of the plurality of conductive spiral coils comprises:
a length that is less than or equal to ½ wavelength of a maximum frequency of the given frequency band.
9. The PAMM of claim 1 further comprises:
each of the plurality of conductive spiral coils is of a given size, a given pattern, and of a given length; and
the metal backing is a distance “d” from the first layer such that at least a desired property of the PAMM is substantially obtained.
10. The PAMM of claim 1 further comprises:
a second antenna element on a fourth layer of the substrate that is constructed to service communications in the given frequency band, the third layer of the substrate between the fourth layer and the first layer.
11. The PAMM of claim 1 , wherein at least one of the plurality of conductive spiral coils is a concentric spiral coil and at least one of the plurality of conductive spiral coils is an eccentric spiral coil.
12. A projected artificial magnetic mirror (PAMM) comprises:
a plurality of conductive coils arranged in an array on a first layer of a substrate, wherein a conductive coil of the plurality of coils includes:
a first winding having a first shape;
a second winding having a shape similar to the first shape;
a first coupling circuit that, when enabled, couples the first and second windings in series; and
a second coupling circuit that, when enabled, couples the first and second windings in parallel;
a metal backing on a second layer of the substrate, and
a dielectric material between the first and second layers, wherein the plurality of conductive coils are electrically coupled to the metal backing to form an inductive-capacitive network that, for a given frequency band, substantially reduces surface waves along artificial magnetic conductors having shapes determined, at least in part, by the arrangement of the plurality of conductive coils;
a plurality of antennas on a third layer of the substrate that are constructed to service communications in the given frequency band, the first layer of the substrate between the second layer and the third layer, and the first layer separated from the third layer by other dielectric material; and
additional dielectric material disposed between the plurality of antennas to alter radiation patterns of the plurality of antennas, wherein the artificial magnetic conductor and the plurality of antennas operate to form a plurality of effective dish antennas.
13. The PAMM of claim 12 further comprises:
the first coupling circuit being enabled for a first frequency band; and
the second coupling circuit being enabled for a second frequency band.
14. The PAMM of claim 12 , wherein a conductive coil of the plurality of conductive coils further comprises:
a first selectable tap switch that, when enabled, couples the first winding to the metal backing; and
a second selectable tap switch that, when enabled, couples the second winding to the metal backing.
15. The PAMM of claim 12 further comprises:
a plurality of circuit components formed in the dielectric material.
16. The PAMM of claim 12 , wherein a conductive coil of the plurality of conductive coils further comprises:
a shape that includes at least one of be circular, square, rectangular, hexagon, octagon, and elliptical; and
a pattern that includes at least one of interconnecting branches, an n th order Peano curve, and an n th order Hilbert curve.
17. The PAMM of claim 12 , wherein a conductive coil of the plurality of conductive coils comprises:
a length that is less than or equal to ½ wavelength of a maximum frequency of the given frequency band.
18. The PAMM of claim 12 further comprises:
each of the plurality of conductive coils is of a given size, a given pattern, and of a given length; and
the metal backing is a distance “d” from the first layer such that at least a desired property of the PAMM is substantially obtained.
19. The PAMM of claim 12 further comprises:
a second plurality of conductive coils arranged in an array on a fourth layer of a substrate; and
the dielectric material being between the fourth and second layers of the substrate, wherein the second plurality of conductive coils is electrically coupled to the metal backing to further form the inductive-capacitive network.
20. The PAMM of claim 12 , wherein each of the artificial magnetic conductors has a focal point, at least one of the plurality of antennas positioned within the focal point.