Antenna feeding network
An antenna feeding network for a multi-radiator antenna. The feeding network comprises at least one substantially air filled coaxial line, each comprising a central inner conductor, an elongated outer conductor surrounding the central inner conductor and an elongated rail element slidably movably arranged inside the outer conductor. The rail element is longitudinally movable in relation to at least the outer conductor.
1. An antenna feeding network for a multi-radiator antenna, said feeding network comprising:
at least two phase shifters, each having:
an inner conductor; and
an outer conductor having walls surrounding the inner conductor; and
a support element arranged to support the inner conductor and to define the position of the inner conductor relative to the outer conductor;
a rail element arranged inside the walls of the outer conductor; and
at least one dielectric element attached to said rail element and being longitudinally movable in relation to said conductors.
2. The antenna feeding network according to claim 1 , wherein said at least one dielectric element is configured to cooperate with at least one phase shifter to provide a phase shifting arrangement.
3. The antenna feeding network according to claim 1 , wherein said at least one dielectric element has a U-shaped profile such as to partly surround the inner conductor of at least one phase shifter and to at least partly fill out the cavity between the inner and outer conductors of said at least one phase shifter.
4. The antenna feeding network according to claim 1 , wherein said outer conductor is provided with guiding means configured to guide the rail element inside the outer conductor.
5. The antenna feeding network according to claim 4 , wherein said guiding means comprises at least one longitudinally extending protrusion provided on the inside of said outer conductor.
6. The antenna feeding network according to claim 1 comprising a plurality of said phase shifters and means for moving at least two rail elements of said phase shifters simultaneously at different speed.
7. The antenna feeding network according to claim 6 , wherein said means for moving comprises a longitudinally extending rod and at least first and second connecting elements, each being mechanically connected to respective at least first and second rail elements of said at least two rail elements, wherein each connecting element is provided with an internally threaded portion, said threaded portions being configured to co-operate with corresponding threaded segments of said rod, wherein said threaded segments have different pitch such that said first connecting element and first rail element moves at a different speed than said second connecting element and second rail element when said rod is rotated.
8. The antenna feeding network according to claim 7 , wherein said means for moving comprises at least one electric motor arranged to rotate said longitudinally extending rod and means for electrically controlling said electric motor from a distance.
9. The antenna feeding network according to claim 2 , wherein said support element is configured to position the inner conductor relative to the outer conductor.
10. The antenna feeding network according to claim 1 further comprising at least one holding element configured to attach said inner conductor to said outer conductor.
11. The antenna feeding network according to claim 1 , wherein said outer conductor is configured to form a cavity around the inner conductor.