Cavity-backed slot antenna

1. A device comprising:

a cavity-backed slot antenna; and

a flexible planar transmission line to feed the cavity-backed slot antenna, the flexible planar transmission line including:

a conductive strip separated from one or more ground planes by a dielectric, wherein the conductive strip feeds the cavity-backed slot antenna,

a first segment having a first characteristic impedance,

a second segment, proximate the cavity-backed slot antenna, having a second characteristic impedance, wherein the second characteristic impedance provides impedance for matching a load impedance of the cavity-backed slot antenna, and

a flexible circuit, wherein the cavity-backed slot antenna includes a conductive sidewall formed by the flexible circuit.

2. The device of claim 1 ,

wherein the conductive strip includes a first conductive strip and a second conductive strip,

wherein the first segment includes the first conductive strip having a first width, and

wherein the second segment includes the second conductive strip having a second width.

3. The device of claim 2 , wherein the second width is larger than the first width.

4. The device of claim 3 ,

wherein the second conductive strip includes a connection to one or both of the ground planes.

5. The device of claim 2 , wherein the second width is smaller than the first width.

6. The device of claim 5 , wherein the second conductive strip zig-zags to extend electrical length over the corresponding physical length.

7. The device of claim 1 ,

wherein the flexible circuit defines a slot in the conductive sidewall of the cavity-backed slot antenna, and

wherein the conductive sidewall formed by the flexible circuit is electrically connected to other conductive sidewalls of the cavity-backed slot antenna.

8. The device of claim 7 , wherein the conductive sidewall formed by the flexible circuit is continuous with one of the ground planes of the flexible planar transmission line.

9. The device of claim 8 , wherein the cavity-backed slot antenna includes a feed, wherein the feed is continuous with the conductive strip of the flexible planar transmission line.

10. The device of claim 9 ,

wherein the flexible planar transmission line to feed the cavity-backed slot antenna includes a stripline,

wherein the conductive strip separated from one or more ground planes is a central conductor separated from two ground planes, and

wherein the feed emerges from the stripline proximate an edge of the slot of the cavity-backed slot antenna.

11. The device of claim 9 ,

wherein the flexible planar transmission line to feed the cavity-backed slot antenna includes a stripline,

wherein the conductive strip separated from one or more ground planes is a central conductor separated from two ground planes, and

wherein the feed emerges from the stripline proximate an edge of the cavity-backed slot antenna at which the stripline meets the cavity-backed slot antenna.

12. The device of claim 8 , wherein the flexible circuit includes a conductive plane that coincides with the conductive sidewall to act as a floating resonator.

13. The device of claim 8 , wherein the flexible circuit includes a conductive strip that coincides with the slot to act as a resonator.

14. The device of claim 1 , further comprising:

one or more lumped components electrically connected to the second segment wherein the lumped components provide impedance for matching the load impedance of the cavity-backed slot antenna.

15. A device comprising:

a display having a housing and a bezel;

a cavity-backed slot antenna situated within the bezel; and

a flexible planar transmission line to feed the cavity-backed slot antenna, the flexible planar transmission line including:

a conductive strip separated from one or more ground planes by a dielectric, wherein the conductive strip feeds the cavity-backed slot antenna,

a first segment having a first characteristic impedance,

a second segment, proximate the cavity-backed slot antenna, having a second characteristic impedance, wherein the second characteristic impedance provides impedance for matching a load impedance of the cavity-backed slot antenna, and

a flexible circuit, wherein the cavity-backed slot antenna includes a conductive sidewall formed by the flexible circuit.

16. The device of claim 1 ,

wherein the conductive strip includes a first conductive strip and a second conductive strip,

wherein the first segment includes the first conductive strip having a first width,

wherein the second segment includes the second conductive strip having a second width, and

wherein the second width is different than the first width or wherein the second conductive strip zig-zags to extend electrical length over the corresponding physical length.

17. The device of claim 15 ,

a flexible circuit, wherein the cavity-backed slot antenna includes a conductive sidewall formed by the flexible circuit,

wherein the conductive sidewall formed by the flexible circuit is electrically connected to other conductive sidewalls of the cavity-backed slot antenna,

wherein the flexible circuit defines a slot in the conductive sidewall of the cavity-backed slot antenna,

wherein the conductive sidewall formed by the flexible circuit is continuous with one of the ground planes of the flexible planar transmission line, and

wherein the cavity-backed slot antenna includes a feed, wherein the feed is continuous with the conductive strip of the flexible planar transmission line.

18. The device of claim 9 ,

wherein the flexible planar transmission line to feed the cavity-backed slot antenna includes a stripline,

wherein the conductive strip separated from one or more ground planes is a central conductor separated from two ground planes, and

wherein the feed emerges from the stripline proximate an edge of the slot of the cavity-backed slot antenna or wherein the feed emerges from the stripline proximate an edge of the cavity-backed slot antenna at which the stripline meets the cavity-backed slot antenna.

19. The device of claim 18 ,

wherein the flexible circuit includes a conductive plane that coincides with the conductive sidewall to act as a floating resonator or wherein the flexible circuit includes a conductive strip that coincides with the slot to act as a resonator.