Antenna assembly utilizing metal-dielectric resonant structures for specific absorption rate compliance

1. A wireless communication device having a housing with an exterior surface which is designed to face a user when the wireless communication device is transmitting a radio frequency signal, said wireless communication device comprising:

an antenna disposed inside the housing for emitting a radio frequency signal; and

a metal-dielectric structure that resonates to reflect the radio frequency signal and that is located between the antenna and the exterior surface at a position wherein the metal-dielectric structure reduces a specific absorption rate of the wireless communication device.

2. The wireless communication device as recited in claim 1 wherein the metal-dielectric structure is located at a position at which the radio frequency signal has an intensity in excess of a predefined threshold level.

3. The wireless communication device as recited in claim 1 further comprising:

a substrate of dielectric material and having a first surface and a second surface on opposite sides of the substrate, wherein the antenna is disposed on the substrate; and

a ground plane formed by a layer of electrically conductive material on the first surface.

4. The wireless communication device as recited in claim 3 wherein the metal-dielectric structure is supported by the substrate.

5. The wireless communication device as recited in claim 3 wherein the metal-dielectric structure comprises a metal pattern on the second surface of the substrate.

6. The wireless communication device as recited in claim 1 wherein the metal-dielectric structure is on a surface of the housing.

7. The wireless communication device as recited in claim 1 wherein the metal-dielectric structure comprises a rectilinear ring within which is an element shaped as a Jerusalem cross.

8. The wireless communication device as recited in claim 1 wherein the metal-dielectric structure comprises a pair of concentric rings each having a gap.

9. The wireless communication device as recited in claim 8 wherein the gap is on a side of one ring that is opposite to a side of the other ring on the other gap is located.

10. The wireless communication device as recited in claim 8 wherein the pair of concentric rings are either circular or rectilinear.

11. The wireless communication device as recited in claim 8 further comprising a switch for selectively creating an electrical path between the pair of concentric rings that alters a resonant frequency of the metal-dielectric structure.

12. The wireless communication device as recited in claim 1 wherein the metal-dielectric structure resonates at a given frequency; and further comprising a device for varying the given frequency.

13. The wireless communication device as recited in claim 12 wherein the device comprises a layer of liquid crystal polymer on which the metal-dielectric structure is mounted; and a circuit for applying a variable voltage to the layer.

14. The wireless communication device as recited in claim 1 wherein the metal-dielectric structure is isolated from electrical ground of the wireless communication device.

15. A wireless communication device having a housing with an exterior surface which is designed to face a user when the wireless communication device is transmitting a radio frequency signal, said wireless communication device comprising:

a substrate of dielectric material and having a first surface and a second surface on opposite sides of the substrate;

a ground plane formed by a layer of electrically conductive material on the first surface;

a first antenna disposed on the substrate;

a second antenna disposed on the substrate and spaced apart from the first antenna; and

a plurality of metal-dielectric structures located between first and second antennas and the exterior surface of the housing, wherein each metal-dielectric structure resonates at a given frequency to reflect the radio frequency signal and thereby affect a specific absorption rate of the wireless communication device.

16. The wireless communication device as recited in claim 15 wherein plurality of metal-dielectric structures are located in a non-periodic array.

17. The wireless communication device as recited in claim 15 wherein each of the plurality of metal-dielectric structures is at a location where the radio frequency signal has an intensity that exceeds a predefined threshold.

18. The wireless communication device as recited in claim 15 wherein each of the plurality of metal-dielectric structures is on the substrate.

19. The wireless communication device as recited in claim 15 wherein each of the plurality of metal-dielectric structures comprises a pair of either circular or rectilinear concentric rings, each having a gap.

20. The wireless communication device as recited in claim 19 wherein the gap is on a side of one ring that is opposite to a side of the other ring on the other gap is located.

21. The wireless communication device as recited in claim 19 further comprising a switch for selectively creating an electrical path between the pair of concentric rings of one of the plurality of metal-dielectric structures, wherein the electrical path alters a resonant frequency of that one metal-dielectric structure.

22. The wireless communication device as recited in claim 15 wherein each of the plurality of metal-dielectric structures comprises a rectilinear ring within which is an element shaped as a Jerusalem cross.

23. The wireless communication device as recited in claim 15 further comprising a device for dynamically varying the given frequency of each of the plurality of metal-dielectric structures.

24. The wireless communication device as recited in claim 15 further comprising a layer of liquid crystal polymer on the substrate adjacent to the plurality of metal-dielectric structures; and a circuit for applying a variable voltage to the layer which thereby defines the given frequency at which each of the plurality of metal-dielectric structures resonates.