Broadband RF radial waveguide feed with integrated glass transition
An antenna and method for using the same are disclosed. In one embodiment, an antenna comprises a radial waveguide; an aperture operable to radiate radio frequency (RF) signals in response to an RF feed wave fed by the radial waveguide; and a radio frequency (RF) choke operable to block RF energy from exiting through a gap between outer portions of the waveguide and the aperture.
1. An antenna comprising:
a radial waveguide having a structure through which an RF feed wave propagates, wherein the structure has an outer portion surrounding an area of the waveguide;
an aperture operable to radiate radio frequency (RF) signals in response to the RF feed wave fed from the outer portion of the radial waveguide without a fixed physical connection to the waveguide, a first surface of the outer portion of the radial waveguide facing and overlapping a second surface at a bottom and outer portion of the aperture to form a gap between the first and second surfaces, the first and second surfaces to move laterally with respect to each other in response to heat due to differences in coefficients of thermal expansion of the waveguide and the aperture; and
a radio frequency (RF) choke operable to block RF energy from exiting through the gap between outer portions of the waveguide and the aperture.
2. The antenna defined in claim 1 wherein no electrically conductive connection exists between the waveguide and the aperture.
3. The antenna defined in claim 1 wherein the second surface is part of a slip plane attached to a bottom of the aperture.
4. The antenna defined in claim 1 wherein the waveguide comprises metal and the aperture comprises a glass or liquid crystal display (LCD) substrate.
5. The antenna defined in claim 1 wherein the RF choke comprises one or more slots in the outer portion of the waveguide in the gap with each of the one or more slots being used to block RF energy of a frequency band.
6. The antenna defined in claim 5 wherein the one or more slots are part of a pair of rings in the outer portion of the waveguide.
7. The antenna defined in claim 1 wherein the RF choke comprises an electromagnetic band gap (EBG) structure.
8. The antenna defined in claim 7 wherein the EBG structure comprises a substrate with one or more vias.
9. The antenna defined in claim 8 wherein the substrate comprises a printed circuit board (PCB) with one or more electrically conductive pads and the one or more vias are plated with electrically conductive material.
10. The antenna defined in claim 9 wherein the PCB is attached with conductive adhesive to the waveguide.
11. The antenna defined in claim 1 wherein the aperture has a slotted array of antenna elements, wherein the slotted array comprises:
a plurality of slots;
a plurality of patches, wherein each of the patches is co-located over and separated from a slot in the plurality of slots, forming a patch/slot pair, each patch/slot pair being turned off or on based on a magnitude of a voltage applied to the patch in the pair.
12. The antenna defined in claim 11 wherein the antenna elements are controlled and operable together to form a beam for a frequency band for use in holographic beam steering.
13. An antenna comprising:
a radial waveguide having a structure through which an RF feed wave propagates, wherein the structure has an outer portion surrounding an area of the waveguide;
an aperture operable having a plurality of antenna elements to radiate radio frequency (RF) signals in response to the RF feed wave fed from the outer portion of the radial waveguide without a fixed physical connection to the waveguide, a first surface of the outer portion of the radial waveguide facing and overlapping a second surface at a bottom and outer portion of the aperture to form a gap between the first and second surfaces, the first and second surfaces to move laterally with respect to each other in response to heat due to differences in coefficients of thermal expansion of the waveguide and the aperture; and
an antenna feed coupled to the waveguide to feed the RF feed wave into the waveguide;
a layer between the waveguide and the aperture around which the feed wave travels to feed the plurality of antenna elements from outer edges of the layer; and
a radio frequency (RF) choke operable to block RF energy from exiting through the gap between outer portions of the waveguide and the aperture.
14. The antenna defined in claim 13 wherein the layer comprises at least one of a group consisting of a ground layer and a dielectric layer.
15. The antenna defined in claim 13 wherein no electrically conductive connection exists between the waveguide and the aperture.
16. The antenna defined in claim 13 wherein the second surface is part of a slip plane attached to a bottom of the aperture.
17. The antenna defined in claim 13 wherein the waveguide comprises metal and the aperture comprises a glass or liquid crystal display (LCD) substrate.
18. The antenna defined in claim 13 wherein the RF choke comprises one or more slots in the outer portion of the waveguide in the gap with each of the one or more slots being used to block RF energy of a frequency band.
19. The antenna defined in claim 18 wherein the one or more slots are part of a pair of rings in the outer portion of the waveguide.
20. The antenna defined in claim 13 wherein the RF choke comprises an electromagnetic band gap (EBG) structure.
21. The antenna defined in claim 20 wherein the EBG structure comprises a substrate with one or more vias.
22. The antenna defined in claim 21 wherein the substrate comprises a printed circuit board (PCB) with one or more electrically conductive pads and the one or more vias are plated with electrically conductive material.
23. The antenna defined in claim 22 wherein the PCB is attached with conductive adhesive to the waveguide.
24. The antenna defined in claim 13 wherein the aperture has a slotted array of antenna elements, wherein the slotted array comprises:
a plurality of slots;
a plurality of patches, wherein each of the patches is co-located over and separated from a slot in the plurality of slots, forming a patch/slot pair, each patch/slot pair being turned off or on based on a magnitude of a voltage applied to the patch in the pair.
25. The antenna defined in claim 24 wherein liquid crystal is between each slot of the plurality of slots and its associated patch in the plurality of patches.
26. The antenna defined in claim 25 further comprising a controller that applies a control pattern that controls which patch/slot pairs are on and off, thereby causing generation of a beam.
27. The antenna defined in claim 13 wherein the antenna elements are controlled and operable together to form a beam for a frequency band for use in holographic beam steering.
28. An antenna comprising:
a radial waveguide having a structure through which an RF feed wave propagates, wherein the structure has an outer portion surrounding an area of the waveguide;
an aperture operable to radiate radio frequency (RF) signals in response to the RF feed wave fed from the outer portion of the radial waveguide without a fixed physical connection to the waveguide, a first surface of the outer portion of the radial waveguide facing and overlapping a second surface at a bottom and outer portion of the aperture to form a gap between the first and second surfaces, the first and second surfaces to move laterally with respect to each other in response to heat due to differences in coefficients of thermal expansion of the waveguide and the aperture, wherein the aperture has a slotted array of antenna elements, wherein the slotted array comprises:
a plurality of slots;
a plurality of patches, wherein each of the patches is co-located over and separated from a slot in the plurality of slots, forming a patch/slot pair, each patch/slot pair being turned off or on based on a magnitude of a voltage applied to the patch in the pair;
a radio frequency (RF) choke operable to block RF energy from exiting through the gap between outer portions of the waveguide and the aperture; and
wherein no electrically conductive connection exists between the waveguide and the aperture.