Mobile antenna system for satellite communications
View Patent ↗Antenna system that includes a plurality of antenna arrangements, each having one or more ports, and all ports connected through transmission lines in a combining/splitting circuit. The antenna arrangements form a spatial phased array able to track a satellite in an elevation plane by mechanically rotating the antenna arrangements about transverse axes giving rise to generation of respective elevation angles and changing the respective distances between the axes in a predefined relationship with the respective elevation angles. The combining/splitting circuit provides phasing and signal delay in order to maintain pre configured radiating parameters. The arrangements can be mounted on a rotating platform to provide azimuth tracking. The system provides dynamic tracking of satellite signals and can be used for satellite communications on moving vehicles.
1. Antenna system comprising at least two antenna arrangements, each having at least one port, and all ports connected through transmission lines in a combining/splitting circuit, where said antenna arrangements form a spatial element array able to track a target in an elevation plane by mechanically rotating the antenna arrangements about transverse axes giving rise to generation of respective elevation angles and changing the respective distances between said axes in a predefined relationship at least with the respective elevation angles; said combining/splitting circuit provides phasing and signal delay in order to maintain pre configured radiating parameters.
2. The antenna system of claim 1 , wherein projections of said antenna arrangements on a plane perpendicular to the elevation direction are touching or overlapping.
3. The antenna system of claim 1 , wherein said antenna arrangements are planar element arrays.
4. The antenna system according to claim 3 , wherein said planar element arrays being planar phased arrays.
5. The antenna system of claim 1 , wherein said antenna arrangements are conformal element arrays.
6. The antenna system according to claim 5 , wherein said conformal element arrays being conformal phased arrays.
7. The antenna system of claim 1 , wherein said antenna arrangements being one from a group that includes reflector antenna, lens antenna and horn antenna.
8. The antenna system of claim 1 , wherein said respective elevation angles are identical (e) for all antenna arrangements and said respective distances are identical (D) between each neighboring axes.
9. The antenna system of claim 8 , wherein said relationship substantially complies with the following equation:
D
=
1
sin
(
e
)
*
W
,
where D represents the distance between said axes, e represents said elevation angle, and W represents a width of each antenna arrangement.
10. The antenna system of claim 1 , wherein the antenna arrangements are able to track a target in an elevation plane by further providing respective tilt angles θ from a normal to an aperture plain of a corresponding antenna arrangement; the respective distances between said axes are changed in a predefined relationship at least with the respective elevation angles and the respective tilt angles.
11. The antenna system of claim 10 , wherein said respective elevation angles are identical (e) for all antenna arrangements and said respective distances are identical (D) between each neighboring axes, and the respective tilt angles θ are identical for all antenna arrangements.
12. The antenna system of claim 11 , wherein said relationship substantially complies with the following equation:
D
=
cos
(
θ
)
sin
(
e
)
*
W
where D represents the distance between said axes, e represents the elevation angle, W represents a width of each antenna arrangement, and θ represents said tilt angle.
13. The system according to claim 12 , wherein said tilt angle is static.
14. The system according to claim 12 , wherein said tilt angle can be steered.
15. The antenna system according to claim 1 , wherein each antenna arrangement has more than one signal port providing more than one polarization.
16. The antenna system according to claim 15 , wherein said more than one polarization includes linear vertical or linear horizontal polarization.
17. The antenna system according to claim 16 , wherein said more than one polarization includes left hand circular or right hand circular polarization.
18. The system of claim 16 , wherein said linear vertical or linear horizontal polarization are combined to form dual/single linear polarizations with any polarization tilt angles.
19. The antenna system according to claim 15 , wherein said more than one polarization includes left hand circular or right hand circular polarization.
20. The antenna system according to claim 1 , wherein said arrangements provide either or both of transmit and receive mode.
21. The antenna system according to claim 1 , wherein each one of said antenna arrangements consists of more than one planar element array antenna module.
22. The antenna system according to claim 21 , wherein said planar element array antenna modules being planar phase array antenna modules.
23. The antenna system according to claim 1 , wherein the relationship between the respective distances and the respective elevation angles is non-linear chosen to maximize gain and minimize side lobes for a whole field of view, and performing selected overlapping of projections towards the target for lower elevation angles.
24. The antenna system of claim 1 , wherein said target being a selected satellite, and wherein said antenna is configured to be fitted on mobile vehicle, for communicating with satellite signals during stationary and moving states of said vehicle.
25. The antenna system according to claim 24 , wherein said vehicle being any of: train, bus, SUV, RV, boat, car, and aircraft.
26. The system according to claim 24 , wherein said antenna is configured to be fitted on mobile vehicle, for receiving Satellite signal during stationary and moving states of said vehicle.
27. The system according to claim 1 , being of up to 13 cm height when fitted on a vehicle.
28. The system according to claim 1 , being of up to 10 cm height when fitted on a vehicle.
29. An antenna system including at least two antenna arrangements mounted on a common rotary platform, using a carriage for each arrangement which provides mechanical bearing for an axis perpendicular to the elevation plane of the antenna arrangement, to thereby provide its elevation movement; wherein the axes of rotation of all antenna arrangements are parallel each to other; two rails joined with the carriages are mounted on the rotary platform at their bottom side, driving means providing linear guided movement of the axes of rotation in direction perpendicular to the axes of rotation of the antenna arrangements.
30. The system according to claim 29 , being of up to 13 cm height when fitted on a vehicle.
31. The system according to claim 29 , being of up to 10 cm height when fitted on a vehicle.
32. An antenna system comprising: at least two antenna arrangements each accommodating a transverse axis; a mechanism for rotating the arrangements in order to track a target in the azimuth plane, and rotating each arrangement about its transverse axis in order to track the target in the elevation plane; mechanism for moving the transverse axes one with respect to the other so as to maintain substantially no gaps between antenna apertures as viewed for any elevation angle within selectable elevation angle range.
33. The system according to claim 32 , being of up to 13 cm height when fitted on a vehicle.
34. The system according to claim 32 , being of up to 10 cm height when fitted on a vehicle.
35. An antenna system comprising: at least two antenna arrangements each accommodating a transverse axis; a mechanism for rotating the arrangements in order to track a target in the azimuth plane, and rotating each arrangement about its transverse axis in order to track the target in the elevation plane; mechanism for moving the transverse axes one with respect to the other, so as to maintain substantially no gaps between antenna apertures for any location where a target is in the field of view of the antenna system.
36. The system according to claim 35 , being of up to 13 cm height when fitted on a vehicle.
37. The system according to claim 35 , being of up to 10 cm height when fitted on a vehicle.
38. An antenna system comprising: at least two antenna arrangements each accommodating a transverse axis; a mechanism for rotating the arrangements in order to track a target in the azimuth plane, and rotating each arrangement about its transverse axis in order to track the target in the elevation plane; mechanism for moving the transverse axes one with respect to the other, whilst maintaining antenna gain and side lobes level within a predefined range for any elevation angle within a pre-defined range of elevation angles.
39. The antenna system according to claim 38 , wherein said mechanism is configured to move the transverse axes one with respect to the other, whilst maintaining antenna gain and side lobes level substantially the same for any elevation angle within a pre-defined range of elevation angles.
40. The antenna system according to claim 38 , further providing mechanism for providing tilt angle for each arrangement, for reducing the side lobe level.
41. The system according to claim 40 , wherein said tilt angle is static.
42. The system according to claim 40 , wherein said tilt angle can be steered.
43. The system according to claim 38 , being of up to 13 cm height when fitted on a vehicle.
44. The system according to claim 38 , being of up to 10 cm height when fitted on a vehicle.
45. An antenna system comprising: at least two antenna arrangements each accommodating a transverse axis; a mechanism for rotating the arrangements in order to track a target in the azimuth plane, and rotating each arrangement about its transverse axis in order to track the target in the elevation plane; mechanism for moving the transverse axes one with respect to the other; the antenna system is not taller than 13 cm.