Linear-to-circular polarizer antenna
A linear-to-circular polarizer antenna is disclosed. In accordance with embodiments of the invention, the polarizer antenna includes an antenna operable to transmit and receive polarized signals and a linear-to-circular polarizer coupled to the antenna. The polarizer includes a plurality of cascaded elements, waveplates or anisotropic sheets, having biaxial permittivity. Each cascaded element has a principal axis rotated at different angles relative to an adjacent element about a z-axis of a 3-dimensional x, y, z coordinate system, and each element is composed of an artificial anisotropic dielectric. The polarizer further includes impedance matching layers disposed adjacent the cascaded elements.
1. A polarizer antenna, comprising:
an antenna operable to at least one of transmit and receive polarized signals;
a linear-to-circular polarizer coupled to the antenna, the polarizer including:
a plurality of cascaded waveplates having biaxial permittivity, each waveplate having a principal axis rotated at different angles relative to an adjacent waveplate about a z-axis of a 3-dimensional x, y, z coordinate system; and
impedance matching layers disposed adjacent the cascaded waveplates.
2. The polarizer antenna of claim 1 , where the linear-to-circular polarizer includes a first assembly of impedance matching layers disposed adjacent a first waveplate of the cascaded waveplates, and a second assembly of impedance matching layers disposed adjacent a second waveplate of the cascaded waveplates.
3. The polarizer antenna of claim 1 , where the plurality of cascaded waveplates comprises four waveplate assemblies, and each assembly is rotated at a different angle relative to an adjacent waveplate assembly.
4. The polarizer antenna of claim 2 , where a first waveplate is rotated at a first angle relative about the z-axis, a second waveplate is rotated at a second angle about the z-axis, a third waveplate is rotated at a third angle about the z-axis, and a fourth waveplate is rotated at a fourth angle about the z-axis, the selection of the first, second and third angles based on operating wavelengths of the polarizer.
5. The polarizer antenna of claim 1 , where each waveplate has a respective length with respect to the z-axis different from a length of an adjacent waveplate.
6. The polarizer antenna of claim 1 , where the waveplates have a biaxial permittivity.
7. The polarizer antenna of claim 1 , where the impedance matching layers comprise a first assembly of impedance matching layers and a second assembly of impedance matching layers, each of the first and second assemblies of impedance matching layers comprising a first section having a first permittivity ∈ 1 , a second section having a second permittivity ∈ 2 greater than the first permittivity, and a third section having a third permittivity ∈ 3 greater than the second permittivity.
8. The polarizer antenna of claim 7 , where each assembly of impedance matching layers comprises a plurality of different substrates.
9. The polarizer antenna of claim 1 , where each waveplate comprises a unit cell of an artificial anisotropic dielectric.
10. The polarizer antenna of claim 9 , where each unit cell comprises a substrate patterned with a copper patch.
11. The polarizer antenna of claim 1 , where the antenna is an electronically active scanning array (EASA).
12. A polarizer antenna, comprising:
an antenna operable to at least one of transmit and receive polarized signals;
a linear-to-circular polarizer coupled to the antenna, the polarizer including:
a plurality of cascaded waveplates having biaxial permittivity, each cascaded waveplate having a principal axis rotated at different angles relative to an adjacent section about a z-axis of a 3-dimensional x, y, z coordinate system, each of the plurality of cascaded waveplates comprising an assembly of printed circuit boards, and
impedance matching layers disposed adjacent the cascaded waveplates, the impedance matching layers comprising a first assembly of impedance matching layers and a second assembly of impedance matching layers, each of the first and second assemblies of impedance matching layers comprising a first section having a first permittivity ∈ 1 , a second section having a second permittivity ∈ 2 greater than the first permittivity, and a third section having a third permittivity ∈ 3 greater than the second permittivity.
13. The polarizer antenna of claim 12 , where a first waveplate is rotated at a first angle relative about the z-axis, a second waveplate is rotated at a second angle about the z-axis, a third waveplate is rotated at a third angle about the z-axis, and a fourth waveplate is rotated at a fourth angle about the z-axis, the first, second and third angles selected being selected based on operating wavelengths of the polarizer.
14. The polarizer antenna of claim 12 , where each waveplate has a respective length with respect to the z-axis different from a length of an adjacent waveplate.
15. The polarizer antenna of claim 12 , where the waveplates have a biaxial permittivity.
16. The polarizer antenna of claim 12 , where each assembly of impedance matching layers comprises a plurality of different substrates.
17. The polarizer antenna of claim 12 , where each waveplate comprises a unit cell of an artificial anisotropic dielectric.
18. The polarizer antenna of claim 17 , where each unit cell comprises a substrate patterned with a copper patch.
19. The polarizer antenna of claim 12 , where the antenna is an electronically active scanning array (EASA).