Curved surface scattering antennas
Surface scattering antennas on curved manifolds provide adjustable radiation fields by adjustably coupling scattering elements along a wave-propagating structure.
1. An antenna, comprising:
a waveguide configured to propagate a guided wave along a curved manifold; and
a plurality of adjustable subwavelength radiators positioned along the curved manifold and coupled to the waveguide;
wherein the adjustable subwavelength radiators are configured to define a holographic function on the curved manifold;
wherein the guided wave has a propagation direction, and the subwavelength radiators have inter-element spacings along the propagation direction substantially less than a free-space wavelength corresponding to an operating frequency of the antenna; and
wherein each of the plurality of subwavelength radiators includes an adjustable surface mount component connected to a surface of the curved circuit board.
2. The antenna of claim 1 , wherein the curved manifold corresponds to a curved circuit board that supports the waveguide.
3. The antenna of claim 2 , wherein the curved circuit board is a semirigid PCB that has been bent to conform to the curved manifold.
4. The antenna of claim 3 , wherein the semirigid PCB is a microwave laminate PCB.
5. The antenna of claim 4 , wherein the microwave laminate PCB is a PTFE laminate PCB.
6. The antenna of claim 2 , wherein the curved circuit board is a flexible PCB.
7. The antenna of claim 6 , wherein the flexible PCB is a polyimide laminate PCB.
8. The antenna of claim 6 , wherein the flexible PCB is a liquid crystal polymer laminate PCB.
9. The antenna of claim 2 , wherein the waveguide is a substrate-integrated waveguide.
10. The antenna of claim 2 , wherein the waveguide is a stripline or microstrip waveguide.
11. The antenna of claim 1 , wherein each surface mount component is connected to the surface of the curved circuit board with an elastomeric conductive compound.
12. The antenna of claim 1 , wherein each surface mount component is connected to the surface of the curved circuit board with flexible contacts.
13. A method of making a curved antenna, comprising:
identifying a desired curvature for the curved antenna;
obtaining a circuit board that includes a waveguide and a plurality of adjustable subwavelength radiators coupled to the waveguide; and
bending the circuit board to conform to the desired curvature;
wherein the adjustable subwavelength radiators are configured to define a holographic function for the desired curvature;
wherein the waveguide has a propagation direction, and the adjustable subwavelength radiators have inter-element spacings along the propagation direction substantially less than a free-space wavelength corresponding to an operating frequency of the antenna; and
wherein the obtaining of the circuit board includes, prior to the bending:
selectively applying solder paste to an upper surface of the circuit board; and
placing a plurality of adjustable surface mount components on the circuit board to form connections via the selectively applied solder paste, the plurality of adjustable surface mount components corresponding to the plurality of adjustable subwavelength radiators.
14. The method of claim 13 , wherein the selectively applying of the solder paste is an applying of the solder paste with a solder screen.
15. The method of claim 13 , wherein the placing of the plurality of surface mount components is a placing with a pick-and-place machine.
16. The method of claim 13 , wherein the obtained circuit board is a circuit board with unbaked solder paste, and the method further comprises:
after the bending, baking the obtained circuit board in a solder reflow oven.
17. A curved antenna fabricated by a method that includes:
identifying a desired curvature for the curved antenna;
obtaining a circuit board that includes a waveguide and a plurality of adjustable subwavelength radiators coupled to the waveguide; and
bending the circuit board to conform to the desired curvature;
wherein the adjustable subwavelength radiators are configured to define a holographic function for the desired curvature;
wherein the waveguide has a propagation direction, and the adjustable subwavelength radiators have inter-element spacings along the propagation direction substantially less than a free-space wavelength corresponding to an operating frequency of the antenna; and
wherein the obtaining of the circuit board includes, prior to the bending:
selectively applying solder paste to an upper surface of the circuit board; and
placing a plurality of surface mount components on the circuit board to form connections via the selectively applied solder paste, the plurality of surface mount components corresponding to the plurality of adjustable subwavelength radiators.
18. The curved antenna of claim 17 , wherein the selectively applying of the solder paste is an applying of the solder paste with a solder screen.
19. The curved antenna of claim 17 , wherein the placing of the plurality of surface mount components is a placing with a pick-and-place machine.
20. The curved antenna of claim 17 , wherein the obtained circuit board is a circuit board with unbaked solder paste, and the method further comprises:
after the bending, baking the obtained circuit board in a solder reflow oven.