Multi-band antenna
A multi-band antenna includes a plurality of dipole antenna each arranged to operate in a frequency band different from each other; a back cavity structure mounted to the plurality of dipole antennas, wherein the plurality of dipole antennas are at least partially accommodated within a back cavity defined by the back cavity structure; and a feed network provided on the back cavity structure and coupled to the plurality of dipole antennas.
1. A multi-band antenna comprising:
a plurality of dipole antenna each arranged to operate in a frequency band different from each other;
a back cavity structure mounted to the plurality of dipole antennas, wherein the plurality of dipole antennas are at least partially accommodated within a back cavity defined by the back cavity structure; and
a feed network provided on the back cavity structure and coupled to the plurality of dipole antennas, wherein the feed network includes a two-stage cascaded hybrid coupler, wherein the feed network is defied with a first set of ports coupled to the plurality of dipole antennas and a second set of ports coupled to external connectors mounted on the back cavity structure, and wherein:
(i) the first set of ports are defined on a base of the back cavity structure proximate to a center position of the base, and the second set of ports are defined proximate to an edge position of the base; or
(ii) the feed network is further defined with a folded side length between a proximate pair of ports in one of the first set of ports and one of the second set of ports.
2. The multi-band antenna in accordance with claim 1 , wherein the plurality of dipole antennas includes a plurality of cross-dipole antennas.
3. The multi-band antenna in accordance with claim 2 , wherein the plurality of cross-dipole antennas comprises a plurality of dipole arms each having a dimension different from each other.
4. The multi-band antenna in accordance with claim 3 , wherein each of the plurality of dipole arms includes a curved structure, wherein the plurality of dipole arms are defined with different subtended angles so as to operate in different frequency bands.
5. The multi-band antenna in accordance with claim 4 , wherein the plurality of cross-dipole antennas are provided on at least one antenna substrate mounted to the back cavity structure.
6. The multi-band antenna in accordance with claim 5 , wherein each of the at least one antenna substrate is provided with the plurality of dipole arms defined on a first side of the respective antenna substrate.
7. The multi-band antenna in accordance with claim 6 , wherein the plurality of dipole arms couple to a slot feeder defined on the respective antenna substrate.
8. The multi-band antenna in accordance with claim 6 , comprising two antenna substrates intersecting with each other.
9. The multi-band antenna in accordance with claim 8 , wherein the two antenna substrates and a base of the back cavity structure are orthogonally arranged.
10. The multi-band antenna in accordance with claim 6 , wherein each of the at least one antenna substrate is provided with a joining structure arranged to cooperate with another joining structure in another antenna substrate.
11. The multi-band antenna in accordance with claim 10 , wherein the joining structure includes a slit formed on the each of the at least one antenna substrate.
12. The multi-band antenna in accordance with claim 6 , wherein each of the at least one antenna substrate is provided with a ground plane on the first side of the substrate.
13. The multi-band antenna in accordance with claim 12 , wherein each of the at least one antenna substrate is further provided with a microstrip feedline on a second side of the substrate, wherein the second side opposites to the first side.
14. The multi-band antenna in accordance with claim 3 , wherein the plurality of cross-dipole antennas includes multiple sets of the plurality of dipole arms.
15. The multi-band antenna in accordance with claim 1 , wherein the plurality of dipole antennas are arranged communicate an electromagnetic signal with circular polarization.
16. The multi-band antenna in accordance with claim 15 , wherein the electromagnetic signal includes a radiation pattern substantially covering the upper hemisphere in both xoz-plane and yoz-plane.
17. The multi-band antenna in accordance with claim 16 , wherein the electromagnetic signal includes a 3-dB axial ratio beamwidth broader than 200°.
18. The multi-band antenna in accordance with claim 1 , wherein the back cavity structure defines a corrugated back cavity.
19. The multi-band antenna in accordance with claim 18 , wherein the back cavity structure comprises a side wall in a corrugated shape.
20. The multi-band antenna in accordance with claim 1 , wherein the feed network is provided on a bottom surface of a base of the back cavity structure, the feed network is coupled to the plurality of dipole antennas provided on an opposite surface of the base through a plurality of via structures.
21. An antenna assembly comprising a plurality of multi-band antenna in accordance with claim 1 arranged in an array.