Beam-steering antenna

Abstract

Beam-steering antenna comprising a mechanically rotatable reflector (5a) and a non-rotating feeder (4a) arranged to feed the rotatable reflector, wherein the rotatable reflector is arranged to rotate (2) about a rotation axis (1) for horizontal beam-steering and the feeder is linearly movable (3) along the rotation axis of the rotatable reflector for vertical beam-steering. In particular, comprising two mechanically rotatable reflectors (5a, 5b) and two non-rotating feeders (4a, 4b), wherein each of the two non-rotating feeders is arranged to feed their respective rotatable reflector, wherein the two rotatable reflectors are arranged to rotate about the rotation axis (1) for horizontal beam-steering and the feeders are linearly movable along the rotation axis of the two rotatable reflectors for vertical beam-steering. The rotatable reflector or reflectors (5a, 5b) may be rotatable for a 360° field-of-view. The feeder or feeders (4a, 4b) may be linearly movable for vertical beam-steering of ±30° field-of-view.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of wireless communication, specifically to a beam-steering antenna with a mechanically rotatable reflector arranged to rotate around a linearly-displaceable feeder.BACKGROUND

[0002] Antennas are critical components of radio systems, playing a key role in transmitter and receiver signals over various frequencies, for several uses. In many cases, beam-steering (or beam-scanning) is required, to direct the transmitter / receiver electromagnetic waves to / from specific directions. This commonly goes together with the need for stable high directivity (or gain), meaning that the antenna is required to effectively spatially filter one direction in respect to others while pointing its main lobe in different directions. Many times, having wide beam-steering angles (also called scanning angles) results in varying and degrading directivity (or gain), highly dependent on the beam direction.

[0003] Beam-steering started with bulky and heavy mechanisms, mostly related to high-power transmission systems such as those involving radar. Radio astronomy exploration also applies similarly large mechanical systems, not for power transmission but with very sensitive reception capabilities. Later came the electronic, analog or digital phased arrays, many of these very sophisticated, where the antenna structures no longer have to physically move to steer their beams in the desired directions. But even these most sophisticated electronically beam-forming antennas, at some point, have their directivity (or gain) degraded and dependent on the beam directions. Also, most require larger sizes or complex structures to achieve high steering flexibility.

[0004] In antenna design, this conflicting balance between beam-steering freedom, directivity (or gain) stability, low size and weight are a constant challenge. These are known problems in mobile antenna uses for Unmanned Aerial Vehicles (UAVs), or Autonomous Vehicles (AVs), commonly going together with lower power transmitters and highly sensitive receivers, either for communications, radar, or other purposes. Especially in UAV applications, having azimuth-only beam-steering is too limiting, since elevation angles most often make part of the system's natural geometry, among UAVs, UAV-control stations, or between UAVs and surrounding obstacles needed to be detected.

[0005] One of the means to reduce the dependence of directivity (or gain) on beam direction is to move physical parts of the antenna, the active and / or the passive elements. Naturally, the larger and heavier the antenna parts are, the sturdier the mechanical parts need to be, and less dynamic and slower is the beam-steering.

[0006] On many situations, where active antenna elements need to rotate in respect to other, Radio-Frequency (RF) rotary joints are used since they provide more beam-steering flexibility, while possibly making the antenna's directivity (or gain) more independent of the steering. But their limitations are known - RF rotary joints introduce relevant RF mismatching and signal losses, besides requiring relevant maintenance on the rotary joint electrical parts.

[0007] In the concerning technical field, prior art rotating, compact and light disclosures have important limitations, in particular for applications that require flexible and dynamic azimuth and elevation beam-steering, with larger FOVs (Fields-of-View) and almost constant directivity (or gain). In fact, there are antenna cases with no dynamic elevation beam-steering capabilities; elevation may, apparently, be fixed throughout the azimuth range, hypothetically being changed by changing the active antenna element, or by making changes to the RF reflector (placing RF absorbing elements and or additional reflectors at either end of the RF reflector).

[0008] Looking further at alternatives such as phased arrays with several active elements, which is another well-known and mature technology for those skilled in the art, these tend to either be large or bulky (often multi-planar and occupying several λ lengths), also involving complex RF or baseband combining / processing methods. Namely, it is still a major problem for phased array solutions to be able to achieve beam-steering with full continuous 360° azimuth, plus elevation beam-steering above and below the antenna, keeping directivity (or gain) almost constant and high-enough while beam-steering.GENERAL DESCRIPTION

[0009] A light and compact beam-steering antenna is disclosed, capable of full continuous 360° azimuth and ±15° elevation dynamic beam-steering, with high and almost constant gain, 360° azimuth and ±30° elevation 3dB-power FOVs. It comprises a mechanically rotating group of two parabolic (or also referred to as paraboloid) reflectors around their two co-linear respective feeders, preferably located at their respective parabolic focus points, and wherein each radiating feeder is mounted to radiate the corresponding passive reflector. The non-rotating feeders are linearly movable along the reflectors rotating axis according to the feeders vertical displacement movement, and have omnidirectional radiating properties in the horizontal plane. Considering vertical placement of the rotation axis, azimuth beam-steering is about the axis of the reflectors rotation according to the reflectors rotation movement, coincident with the feeders line, elevation beam-steering is below / above the plane normal to the axis in any of the azimuth directions. This disclosure does not involve any RF rotary joints, being light and compact, while independently making use of two beam-steering degrees-of-freedom, azimuth and elevation, with excellent directivity (or gain), mutual RF coupling and impedance performance. The two feeders may be used either as combined / uncoupled transmitters (transmitters), or combined / uncoupled receivers (receivers), or one transmitter and one receiver mutually combined / uncoupled.

[0010] The disclosure thus includes reflector rotation and feeder linear displacement support elements, and respective mechanisms. The mechanisms may be motorised, or of any other type.

[0011] The present disclosure relates to the field of beam-steering antennas, for either transmission or reception of electromagnetic waves, for wireless communication, radar systems or other. Along with compactness and lightness, the present disclosure offers independent agility in azimuth and elevation beam-steering, and is particularly useful for mobile vehicle applications with restricted payload capability but which require high antenna directivity (or gain) over large scanning angles in both azimuth and elevation. Applications may range from, but are not limited to, UAVs or AVs.

[0012] Prior art limitations include the expected difficulty in physically and electromagnetically combining two similar antennas in linear tandem, as in the present disclosure. Such difficulty arises from the antenna geometry, as well as the necessary use of additional elements such as the absorbing elements, reflectors and radomes. Unlike the present disclosure, high mutual coupling is expected with the prior art solutions, further relying on the need for additional absorbing and reflector elements, adding to the prior art typically fixed elevation performance limitations.

[0013] Additionally, combining two antennas while keeping the required directivity (or gain) and beam-steering performance, plus compactness and lightness, for either combined / uncoupled transmitters, combined / uncoupled receivers, or one transmitter and one receiver mutually combined / uncoupled configurations, yet poses other difficulties in the prior art solutions.

[0014] The disclosure also provides great flexibility in the combination of the two antenna pairs: i) The two feeders may be used as 2 RF combined transmitters, or as 2 RF combined receivers. RF combining may be relevant in a single-link point-to-point wireless communications system, increasing dynamic range through array gain. ii) The two feeders may be used as 2 RF uncoupled transmitters, or as 2 RF uncoupled receivers. This configuration may be relevant in a) a two-link point-to-point wireless communications system, where the transmitter and receiver antenna pair on the same antenna unit will operate for their own differing link, or b) the antenna pair on the same antenna unit that may be used for spatial diversity combining in a single-link point-to-point wireless communications system. iii) The two feeders may be used as 1 transmitter and 1 receiver, combined in the same radar system, mutually RF uncoupled and co-located. This configuration may be particularly relevant in a radar system, as long as transmitter and receiver antennas are RF uncoupled and both transmitter and receiver antennas are pointing to the same beam-steering location, as happens in the present disclosure.

[0015] In the field of beam-steering antennas, for either transmission or reception of electromagnetic waves, for wireless communication, radar systems or other, for applications such as, but are not limited to, UAVs or AVs, the present disclosure allows the following, altogether: i) two independent beam-steering degrees-of-freedom, azimuth and elevation, capable of full continuous 360° azimuth and ±15° elevation dynamic beam-steering, with high and almost constant gain, 360° azimuth and ±30° elevation 3dB-power FOVs. ii) the location of all mechanical parts to allow the effective movement of the antenna elements to achieve required directivity (or gain) performance together with beam-steering transmitter and / or receiver antenna freedom, not involving any RF rotary joints. iii) the location of all mechanical parts that is particularly favourable to having either 2 combined / uncoupled transmitters, or 2 combined / uncoupled receivers, or 1 transmitter and 1 receiver mutually combined / uncoupled, either physically or electromagnetically effective depending on the configuration. iv) small and light construction.

[0016] Each feeder preferably comprises one or more resonant elements, resulting in open-space omnidirectional radiating properties in the horizontal plane.

[0017] The feeders may be independently connected to their own respective RF antenna connectors and outer cables, above and below the main antenna body, involving no rotary RF joints, only top and bottom mechanical bearings.

[0018] The rotational displacement of each parabolic reflector may be independent of the linear displacement of the respective feeding element along the reflector's axis of rotation, resulting in the independent two degree-of-freedom antenna beam-steering in azimuth and elevation.

[0019] A stepper motor, or similar, may be used for the rotating reflectors movement, transmitting its movement to a spur gear set physically connected to a bearing on the top of the rotary structure element, for its rotating movement.

[0020] A servo motor, or similar, may be used for the linear feeders movement, transmitting its movement to a linear movable lever and shaft on the top of the feeders supporting element, for its vertical movement.

[0021] It is disclosed a beam-steering antenna comprising a mechanically rotatable reflector (5a) and a non-rotating feeder (4a) arranged to feed the rotatable reflector, wherein the rotatable reflector is arranged to rotate (2) about a rotation axis (1) for horizontal beam-steering and the feeder is linearly movable (3) along the rotation axis of the rotatable reflector for vertical beam-steering.

[0022] The feeder (4a) may comprise a resonant feeding element.

[0023] The beam-steering antenna may comprise two mechanically rotatable reflectors (5a, 5b) and two non-rotating feeders (4a, 4b), wherein each of the two non-rotating feeders is arranged to feed one of the two rotatable reflectors, wherein the two rotatable reflectors are arranged to rotate about the rotation axis (1) for horizontal beam-steering and the feeders are linearly movable along the rotation axis of the two rotatable reflectors for vertical beam-steering, in particular wherein each of the two feeders (4a, 4b) comprises a resonant feeding element for feeding each of the two rotatable reflectors (5a, 5b).

[0024] The two mechanically rotatable reflectors (5a, 5b) may be arranged to rotate together about the rotation axis (1).

[0025] The two feeders (4a, 4b) may be arranged to move together along the rotation axis (1).

[0026] It is disclosed a beam-steering antenna wherein: the two mechanically rotatable reflectors (5a, 5b) and the two non-rotating feeders (4a, 4b) are arranged to be used as transmitters, the two mechanically rotatable reflectors (5a, 5b) and the two non-rotating feeders (4a, 4b) are arranged to be used as receivers, or a first rotatable reflector (5a) and a first feeder (4a) are arranged to be used as a transmitter, and a second rotatable reflector (5b) and a second feeder (4b) are arranged to be used as a receiver.

[0027] The rotatable reflector or reflectors (5a, 5b) may be a parabolic reflector or reflectors. The reflector or reflectors (5a, 5b) may be a passive reflector or reflectors.

[0028] The rotatable reflector or reflectors (5a, 5b) may be rotatable for a 360° field-of-view.

[0029] The feeder or feeders (4a, 4b) may be linearly movable along the rotation axis (1) of the rotatable reflector or reflectors for vertical beam-steering of ±30° elevation with 3dB-power field-of-view.

[0030] The feeder or feeders (4a, 4b) may be arranged to be located at a focus point of a respective rotatable reflector or reflectors (5a, 5b).

[0031] The feeder or feeders (4a, 4b) may be omnidirectional in a plane perpendicular to the rotation axis (1) of the rotatable reflector or reflectors.

[0032] The beam-steering antenna may comprise an RF connector (7,8) and respective cable, for each of the feeder or feeders. The beam-steering antenna may comprise a horizontal beam-steering motor (10) for rotating the reflector or reflectors (5a, 5b). The beam-steering antenna may comprise a vertical beam-steering motor (9) for linearly moving the feeder or feeders (4a, 4b).BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, concern embodiments of the disclosure and, together with a general description given above and the detailed description given below, further serve to explain the disclosure. The figures should not be seen as limiting the scope of invention. Figure 1: Schematic 2D drawing representation detailing all main parts of the antenna disclosure, in the preferred embodiment of the antenna. Figure 2: Schematic representation of a 3D model detailing all main parts (a) and a real physical prototype (b) of the preferred embodiment of the antenna. Figure 3: Photographic illustration of an experimental setup for characterisation inside the anechoic chamber, testing the preferred embodiment. Figure 4: Plots of the measured S11-parameter at each of two antenna feeding ports 7 and 8, for an Omnidirectional Microstrip Antenna (OMA), for OMA + feeders central supporting element, and for the full assembly (OMA + central supporting element + reflector) (a) and the full antenna coupling (S21-parameter) between the top 7 and bottom 8 antenna feeding ports of Figure 1 / Figure 2 embodiment. Figure 5: Plot representation of the measured radiation pattern, in azimuth for different reflector rotational directions (a) and in elevation for different linear feed displacement around its central point (b), for each of the reflector-feeder antenna pairs (4a and 5a, 4b and 5b) in the Figure 1 / Figure 2 embodiment. The following elements are indicated in the figures with their respective reference numerals: 1 - Reflectors rotation + feeders linear displacement axis 2 - Reflectors rotation movement 3 - Feeders vertical displacement movement 4a / b - Top / bottom omnidirectional feeding antennas 5a / b - Top / bottom parabolic reflectors 6 - Top / bottom central feeders supporting element 7 - RF port of top antenna (inside part 13) 8 - RF port of bottom antenna (outside part 14) 9 - Servo motor for vertical movement 10 - Stepper motor for rotating movement 11 - Top / bottom spur gears set 12 - Lever and shaft for vertical movement 13 - Static supporting structure 14a - Reflectors rotating supporting element (top part, rigid together with 14b) 14b - Reflectors rotating supporting element (bottom part, rigid together with 14a) 15a - Top bearing between 14a (rigid with 14b) and 13 15b - Bottom bearing between 14b (rigid with 14a) and 8 Figure 6: 3D schematic representation of the central feeders supporting element, showing the most relevant building factors that affect electromagnetic and physical performance. DETAILED DESCRIPTION

[0034] Figure 1 presents a drawing of the exemplary arrangement of the antenna, in the form of the preferred embodiment, showing all relevant parts.

[0035] Figure 2 presents the designed, prototyped and experimentally characterised antenna which is disclosed in the present description, in the form of the preferred embodiment.

[0036] The two independent mechanically rotating parabolic reflectors 5a and 5b are preferably moved rigidly together with the rotating supporting element 14. Top part 14a of 14 rotates around the top part of the feeder supporting structure 6. Bottom part 14b of 14 rotates around the bottom part of the feeder supporting structure 6.

[0037] The reflectors' respective two independent non-rotating feeders 4a and 4b are preferably all in the same axis 1.

[0038] Each feeder 4a and 4b, with omnidirectional properties in the horizontal plane (perpendicular do the axis 1), is preferably placed in each reflectors focus points, also in the axis 1.

[0039] In the preferred embodiment the antenna feeders are OMAs, but any other antenna preferably with omnidirectional properties in the horizontal plane may used. Those skilled in the art know that its electromagnetic size needs to be small relative to its reflector, in order to achieve good elevation beam-steering.

[0040] The dimensions of reflectors 5a and 5b, the location of their focus points and the common rotational axis 1 are directly intertwined and set by parabolic antenna properties known to a person skilled in the art.

[0041] Reflectors 5a and 5b preferably rotate according to 2. The feeders 4a and 4b are preferably moved linearly upward or downward according to 3, preferably independent of the rotation movement 2.

[0042] This configuration enables the antenna to achieve azimuth beam-steering for a full and continuous 360° azimuth reflector antennas revolution, while adding independent elevation dynamic beam-steering for each of the above and bottom antennas reflector-feeder pairs (4a and 5a, or 4b and 5b).

[0043] For Figure 1 / Figure 2 preferred embodiment, Figure 4a) plots the measured S11-parameter at either one of the two antenna feeding ports 7 or 8 (plots are very similar between these), for a single isolated OMA 4a or 4b, for such OMA 4a or 4b with its feeders central supporting element 6, and for the full assembly (OMA 4a or 4b + central supporting element 6 + reflector 5a) or 5b). This preferred embodiment presents a relatively good S11 (<-10dB) between 23 and 24.5 GHz, with an effective bandwidth of 1.5GHz.

[0044] For Figure 1 / Figure 2 preferred embodiment, Figure 4b) plots the measured full antenna mutual coupling (S21-parameter) between the top 7 and bottom 8 antenna ports. This preferred embodiment presents antenna coupling measured to be below - 30dB, ensuring therefore a relatively good isolation between antenna ports 7 and 8.

[0045] The disclosed configuration also allows almost constant high directivity (or gain), for all allowed azimuth and / or elevation beam directions. This is shown in Figures 5a) and 5b), for one of the reflector-feeder pairs (4a and 5a, or 4b and 5b), for azimuth and elevation beam-steering angles, for the preferred embodiment. The other reflector-feeder pair has almost the same pattern response.

[0046] In Figure 5a), from anechoic chamber measurements, azimuth gains are shown for azimuth beam-steering between ±90°, with a maximum 17dBi gain, with ±1.5dB fluctuation, in the entire azimuth range (the remaining ]-180°,-90°[ and ]+90°,+180°[ beam-steering angles exhibit symmetrical patterns due to the azimuth symmetry of the antenna). Global main-to-side-lobe levels are better than 10dB. With the possibility of RF combining both reflector-feeder pairs for 2 transmitter antennas or for 2 receiver antennas, because such pairs are RF uncoupled, the overall gain of the disclosed antenna may improve by 3dB, reaching 20dBi.

[0047] In Figure 5b) elevation patterns are shown for elevation beam-steering main beam directions between ±15°, by shifting the central supporting element 6 within the -10 to +10 mm range. In these patterns the elevation 3dB-power FOVs are between ±30°.

[0048] Due to the superposition principle, due to the consistent and linear beam-steering azimuth or elevation angles, and by controlling azimuth and elevation independently by the reflector rotation and the feeder linear displacement support elements 14 and 6 and mechanisms 9, 10 , 11, 12 and 15, the expected combined azimuth-elevation final patterns are able to have high and almost constant performance within the possible steering directions.

[0049] As depicted in Figure 2b), the prototype major body structure was fabricated in Acrylonitrile Butadiene Styrene (ABS) material, instead of Polylactic Acid (PLA) as in other tested embodiments, to ensure stronger mechanical properties and use thermoplastic materials closer to the ones used in the industry for mass-production. Other materials are possible, via other embodiments.

[0050] The paraboloid reflector metallisation was employed using stamped aluminium foil, offering a lightweight yet durable solution for the antenna structure, making it suitable for compact and light integration, as well as good electromagnetic properties. Other materials are possible and have been tested, via other embodiments, such as conductive paint, gold electrodeposition, copper electroforming or sputtering (sputter deposition), with similar electromagnetic performance varying production cost, technique complexity or materials availability.

[0051] The feeders central supporting element has been built and tested with several materials, such as ABS, Polycarbonate, Polyamide and Polyethylene Terephthalate Glycol (PETG). Other materials are possible. Different materials result in differing solidity and ease of assembly.

[0052] The feeders central supporting element has been tested with several shapes. Different shapes result in differing solidity and ease of assembly, changes in the OMA radiation pattern symmetry, unwanted generation of sidelobes and resonant cavities, or deflection. Figure 6 shows the most relevant factors affecting electromagnetic and physical performance.

[0053] Figure 6 illustrates an embodiment of a structural component configured to provide mechanical support while simultaneously optimizing antenna performance characteristics. The component has a longitudinal body with multiple regions wherein the width is selected to improve sidelobe behaviour of the antenna array. Along the body a plurality of pins are judiciously disposed, positioned both at the sides and centrally, correctly dimensioned in width and length. These characteristics are set to enhance structural stability and reduce deformation under stress. The body further incorporates portions configured to accommodate the feeder element(s), thereby ensuring appropriate support without compromising their electromagnetic function. Flat facing surfaces are also provided at selected regions, for mechanical interfacing and alignment with adjoining mechanical parts.

[0054] By tailoring the geometry-specifically the body width, pin placement, and slack regions-the structure achieves a balance between mechanical strength and electromagnetic performance, particularly with respect to minimizing sidelobes.

[0055] The present disclosure may be seen as providing a combination of two similar antennas in linear tandem, each composed by a single rotating reflector and the respective single linear displaceable non-rotating feeder. Notwithstanding the fact that such single reflector-single feeder is a relevant embodiment of the present disclosure, though more limited in directivity (or gain) and beam-steering transmitter and / or receiver freedom, the axial geometry and the possible location of the mechanical parts of the present disclosure are specifically relevant in the two linear tandem combined single reflector-single feeder preferred combination embodiment. By the hereby disclosed antenna nature, geometry and the possible disclosed locations of the mechanical parts, with the two combined single reflector-single feeder pairs, is it possible for the disclosed antenna to achieve highest and almost constant directivity (or gain) performance together with azimuth-elevation beam-steering transmitter and / or receiver freedom.

[0056] Putting other antenna solutions in their close vicinity, with other antenna types or geometries different from those of the present disclosure, would most likely result in larger, heavier, more complex antenna transmitter / receiver systems, also likely to result in poorer RF / electromagnetic performance.

[0057] It is clear that the drawings in the following description are only some examples of the disclosure, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.

[0058] Where an apparatus feature is described as being operable to provide a function, it will be appreciated that this includes an apparatus feature which provides that function or which is adapted or configured to provide that function.

[0059] Where elements are described as being mechanically connected or connectable, they may be directly mechanically connected. Where elements are described as being RF / electromagnetically connected or connectable, they may be directly RF / electromagnetically connected.

[0060] Where elements are described as being mechanically coupled or coupleable, they may be linked by one or more intervening or interposing elements. Where elements are described as being RF / electromagnetically coupled or uncoupled, they may be directly or indirectly RF / electromagnetically coupled or uncoupled.

[0061] Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.

[0062] The term "comprising" whenever used in this document is intended to indicate the presence of stated features, integers, steps, components, but not to preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0063] The following claims further set out particular embodiments of the disclosure.

Claims

1. Beam-steering antenna comprising a mechanically rotatable reflector (5a) and a non-rotating feeder (4a) arranged to feed the rotatable reflector, wherein the rotatable reflector is arranged to rotate (2) about a rotation axis (1) for horizontal beam-steering and the feeder is linearly movable (3) along the rotation axis of the rotatable reflector for vertical beam-steering.

2. Beam-steering antenna according to any of the previous claims wherein the feeder (4a) comprises a resonant feeding element.

3. Beam-steering antenna according to any of the previous claims comprising two mechanically rotatable reflectors (5a, 5b) and two non-rotating feeders (4a, 4b), wherein each of the two non-rotating feeders is arranged to feed one of the two rotatable reflectors, wherein the two rotatable reflectors are arranged to rotate about the rotation axis (1) for horizontal beam-steering and the feeders are linearly movable along the rotation axis of the two rotatable reflectors for vertical beam-steering, in particular wherein each of the two feeders (4a, 4b) comprises a resonant feeding element for feeding each of the two rotatable reflectors (5a, 5b).

4. Beam-steering antenna according to the previous claim wherein the two mechanically rotatable reflectors (5a, 5b) are arranged to rotate together about the rotation axis (1).

5. Beam-steering antenna according to claim 3 or 4 wherein the two feeders (4a, 4b) are arranged to move together along the rotation axis (1).

6. Beam-steering antenna according to any of the claims 3-5 wherein: the two mechanically rotatable reflectors (5a, 5b) and the two non-rotating feeders (4a, 4b) are arranged to be used as transmitters, the two mechanically rotatable reflectors (5a, 5b) and the two non-rotating feeders (4a, 4b) are arranged to be used as receivers, or a first rotatable reflector (5a) and a first feeder (4a) are arranged to be used as a transmitter, and a second rotatable reflector (5b) and a second feeder (4b) are arranged to be used as a receiver.

7. Beam-steering antenna according to any of the previous claims wherein the rotatable reflector or reflectors (5a, 5b) are a parabolic reflector or reflectors.

8. Beam-steering antenna according to any of the previous claims wherein the reflector or reflectors (5a, 5b) are a passive reflector or reflectors.

9. Beam-steering antenna according to any of the previous claims wherein the rotatable reflector or reflectors (5a, 5b) are rotatable for a 360° field-of-view.

10. Beam-steering antenna according to any of the previous claims wherein the feeder or feeders (4a, 4b) are linearly movable along the rotation axis (1) of the rotatable reflector or reflectors for vertical beam-steering of ±30° elevation with 3dB-power field-of-view.

11. Beam-steering antenna according to any of the previous claims wherein the feeder or feeders (4a, 4b) are arranged to be located at a focus point of a respective rotatable reflector or reflectors (5a, 5b).

12. Beam-steering antenna according to any of the previous claims where the feeder or feeders (4a, 4b) are omnidirectional in a plane perpendicular to the rotation axis (1) of the rotatable reflector or reflectors.

13. Beam-steering antenna according to any of the previous claims comprising an RF connector (7,8) and respective cable, for each of the feeder or feeders.

14. Beam-steering antenna according to any of the previous claims comprising a horizontal beam-steering motor (10) for rotating the reflector or reflectors (5a, 5b).

15. Beam-steering antenna according to any of the previous claims comprising a vertical beam-steering motor (9) for linearly moving the feeder or feeders (4a, 4b).

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