초록 ▼

Surface scattering antennas provide adjustable radiation fields by adjustably coupling scattering elements along a wave-propagating structure. In some approaches, the scattering elements are patch elements. In some approaches, the scattering elements are made adjustable by disposing an electrically

Surface scattering antennas provide adjustable radiation fields by adjustably coupling scattering elements along a wave-propagating structure. In some approaches, the scattering elements are patch elements. In some approaches, the scattering elements are made adjustable by disposing an electrically adjustable material, such as a liquid crystal, in proximity to the scattering elements. Methods and systems provide control and adjustment of surface scattering antennas for various applications.

대표청구항 ▼

1. An antenna, comprising: a wave-propagating structure; anda plurality of subwavelength patch elements distributed along the wave-propagating structure with inter-element spacings less than one-third of a free-space wavelength corresponding to an operating frequency of the antenna, where the plural

1. An antenna, comprising: a wave-propagating structure; anda plurality of subwavelength patch elements distributed along the wave-propagating structure with inter-element spacings less than one-third of a free-space wavelength corresponding to an operating frequency of the antenna, where the plurality of subwavelength patch elements have a plurality of adjustable individual electromagnetic responses to a guided wave mode of the wave-propagating structure, and the plurality of adjustable individual electromagnetic responses provide an adjustable radiation field of the antenna;wherein the wave-propagating structure includes a conducting surface, and the plurality of subwavelength patch elements corresponds to a plurality of conducting patches respectively positioned at least partially above a respective plurality of irises in the conducting surface; andwherein the plurality of conducting patches is configured to provide a plurality of elliptically-polarized radiation fields responsive to iris-intermediated couplings between the conducting patches and the guided wave mode. 2. The antenna of claim 1, wherein the operating frequency is a microwave frequency. 3. The antenna of claim 1, wherein the wave-propagating structure is a two-dimensional wave-propagating structure. 4. The antenna of claim 3, wherein the two-dimensional wave-propagating structure is a parallel plate waveguide, and the conducting surface is an upper conductor of the parallel plate waveguide. 5. The antenna of claim 1, wherein the wave-propagating structure includes a one-dimensional wave-propagating structure. 6. The antenna of claim 5, wherein the one-dimensional wave-propagating structure includes a closed waveguide, and the conducting surface is an upper surface of the closed waveguide. 7. The antenna of claim 1, wherein the guided wave mode defines a plurality of time-dependent H-fields at respective locations of the plurality of irises, and the time-dependent H-fields are vectors sweeping out a plurality of ellipses. 8. The antenna of claim 7, wherein the ellipses are circular. 9. The electromagnetic apparatus of claim 1, wherein the plurality of elliptically-polarized radiation fields is a plurality of left-hand elliptically-polarized radiation fields. 10. The electromagnetic apparatus of claim 1, wherein the plurality of elliptically-polarized radiation fields is a plurality of right-hand elliptically-polarized radiation fields. 11. The electromagnetic apparatus of claim 1, wherein the plurality of elliptically-polarized radiation fields includes a first plurality of right-hand elliptically-polarized radiation fields and a second plurality of left-hand elliptically-polarized radiation fields. 12. The electromagnetic apparatus of claim 1, wherein the plurality of elliptically-polarized radiation fields is a plurality of circularly-polarized radiation fields. 13. The electromagnetic apparatus of claim 1, wherein the wave-propagating structure is a rectangular waveguide, the conducting surface is an upper conductor of the rectangular waveguide, and the plurality of irises are positioned on the upper conductor at locations intermediate between a left edge of the upper conductor and a bisector of the upper conductor. 14. The electromagnetic apparatus of claim 13, wherein the locations intermediate between the left edge and the bisector are locations halfway between the left edge and the bisector. 15. The electromagnetic apparatus of claim 1, wherein: the wave-propagating structure is a rectangular waveguide;the conducting surface is an upper conductor of the rectangular waveguide;the plurality of irises includes a first plurality of irises and a second plurality of irises;the first plurality of irises are positioned on the upper conductor at locations intermediate between a left edge of the upper conductor and a bisector of the upper conductor; andthe second plurality of irises are positioned on the upper conductor at locations intermediate between a right edge of the upper conductor and the bisector of the upper conductor. 16. The electromagnetic apparatus of claim 15, wherein the locations intermediate between the left edge and the bisector are locations halfway between the left edge and the bisector, and the locations intermediate between the right edge and the bisector are locations halfway between the right edge and the bisector. 17. The antenna of claim 1, wherein the wave-propagating structure includes a plurality of one-dimensional wave-propagating structures. 18. The antenna of claim 17, wherein the plurality of one-dimensional wave-propagating structures includes a plurality of closed waveguides, and the conducting surface in one of a plurality of conducting surfaces that are upper surfaces of the closed waveguides. 19. The antenna of claim 1, wherein the wave-propagating structure includes a plurality of one-dimensional wave-propagating structures. 20. The antenna of claim 19, wherein the plurality of one-dimensional wave-propagating structures includes a plurality of closed waveguides, and the conducting surface in one of a plurality of conducting surfaces that are upper surfaces of the closed waveguide. 21. An antenna, comprising: a wave-propagating structure;a plurality of subwavelength patch elements distributed along the wave-propagating structure with inter-element spacings less than one-third of a free-space wavelength corresponding to an operating frequency of the antenna, where the plurality of subwavelength patch elements have a plurality of adjustable individual electromagnetic responses to a guided wave mode of the wave-propagating structure, the plurality of adjustable individual electromagnetic responses provide an adjustable radiation field of the antenna, the wave-propagating structure includes a conducting surface, and the plurality of subwavelength patch elements corresponds to a plurality of conducting patches respectively positioned at least partially above a respective plurality of irises in the conducting surface;a plurality of bias voltage lines configured to provide respective bias voltages between the plurality of conducting patches and the conducting surface; andan electrically adjustable material disposed between the plurality of conducting patches and the plurality of irises in the conducting surface. 22. The antenna of claim 21, wherein the electrically adjustable material includes a liquid crystal material. 23. The antenna of claim 22, further comprising: an alignment layer positioned between the liquid crystal material and the conducting surface, the alignment layer providing microscopic grooves parallel to the conducting surface. 24. The antenna of claim 23, wherein the conducting surface composes at least part of an upper metal layer of a printed circuit board, and the alignment layer is a polyimide layer coating on the upper metal later. 25. The antenna of claim 22, further comprising: an alignment layer positioned between the liquid crystal material and the plurality of conducting patches, the alignment layer providing microscopic grooves parallel to the plurality of conducting patches. 26. The antenna of claim 25, where the plurality of conducting patches compose at least part of a lower metal layer of a printed circuit board, and the alignment layer is a polyimide coating on the lower metal layer. 27. The antenna of claim 22, wherein the electrically adjustable material includes an interstitial medium that embeds the liquid crystal material. 28. The antenna of claim 27, wherein the interstitial medium is a microporous interstitial medium. 29. The antenna of claim 27, wherein the interstitial medium provides microscopic pores for surface alignment of the liquid crystal material, the microscopic pores having long dimensions that are parallel to the conducting surface. 30. The antenna of claim 21, wherein the operating frequency is a microwave frequency. 31. The antenna of claim 21, wherein the wave-propagating structure is a two-dimensional wave-propagating structure. 32. The antenna of claim 31, wherein the two-dimensional wave-propagating structure is a parallel plate waveguide, and the conducting surface is an upper conductor of the parallel plate waveguide. 33. The antenna of claim 21, wherein the wave-propagating structure includes a one-dimensional wave-propagating structure. 34. The antenna of claim 33, wherein the one-dimensional wave-propagating structure includes a closed waveguide, and the conducting surface is an upper surface of the closed waveguide.