A miniaturized spaceborne Ka-band antenna

Abstract

The present invention discloses a miniaturized spaceborne Ka-band antenna, comprising a parabolic primary reflector and a secondary reflector disposed above the primary reflector. A support member is disposed between the primary and secondary reflectors. A feed is disposed through the center of the primary reflector, and a waveguide is disposed below the feed, with a port for signal input. This miniaturized spaceborne Ka-band antenna features a small size, light weight, reliable structure, and high gain.

Description

Technical Field

[0001] The present invention belongs to the field of satellite antennas, and in particular relates to a miniaturized satellite-borne Ka-band antenna. Background Art

[0002] The antenna is a converter that establishes a two-way information transmission channel between satellites to complete inter-satellite communication. In the existing technology, a portion of the input standing wave generated by the sub-surface of the Ka-band antenna will return to the feed source, degrading the input standing wave characteristics of the feed source, failing to ensure good broadband characteristics, and may also destroy the sidelobe characteristics of the antenna. It also has large size, low diffraction ability, and susceptibility to interference, which makes it difficult to achieve high gain within a limited size range.

[0003] Therefore, there is an urgent need for a Ka-band antenna that is small in size, simple in structure, reliable, and has high gain. This is a technical problem that needs to be solved by technicians in this technical field. Summary of the Invention

[0004] The main technical problem solved by the present invention is to provide a miniaturized satellite-borne Ka-band antenna, which solves the problems of large size, complex structure and low gain of Ka-band antennas in the prior art.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is to provide a miniaturized satellite-borne Ka-band antenna, including a parabolic main reflecting surface and a secondary reflecting surface arranged above the main reflecting surface, a support member is arranged between the main reflecting surface and the secondary reflecting surface, a feed source is arranged through the center of the main reflecting surface, and a waveguide is also arranged at the lower part of the feed source, and the waveguide has a port for signal entry.

[0006] In another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention, a cavity is opened inside the waveguide, the cavity is connected to the port, the cavity is divided into a first cavity and a second cavity starting from the port, the first cavity and the second cavity converge at the output part of the cavity, the first cavity and the second cavity have a length difference in the path, and the output part is connected to the feed source.

[0007] In another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention, the feed source includes a conductive portion and a horn that are conductive to each other, the conductive portion is connected to the output portion of the cavity, and the horn is located on the main reflection surface.

[0008] In another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention, the sub-reflector is arranged directly above the feed source, the lower surface of the sub-reflector faces the feed source, and the lower surface of the sub-reflector has an elliptical surface generated around the central axis of the sub-reflector.

[0009] In another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention, the secondary reflector is circular, the diameter of the circle formed by the focus of the main reflector is the same as the diameter of the secondary reflector, and the circle formed by the focus of the main reflector corresponds to the position of the secondary reflector up and down.

[0010] In another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention, one of the foci of the elliptical surface coincides with the focus of the main reflecting surface, and the other focus of the elliptical surface is located at the phase center of the feed source.

[0011] In another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention, a feed hole for inserting the feed source is provided in the center of the main reflecting surface. The shape of the feed hole is adapted to the shape of the conductive portion. The horn extends outward from the terminal end of the conductive portion, and the aperture of the horn gradually increases.

[0012] In another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention, the feed source is a pyramidal horn antenna.

[0013] In another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention, the maximum diameter of the primary reflector is 130 mm, and the maximum diameter of the secondary reflector is 40 mm.

[0014] In another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention, the support member includes a support column, the upper end of the support column is connected to the secondary reflector, the lower end of the support column is connected to the main reflector, and the support column is arranged around the feed source.

[0015] The present invention provides a miniaturized satellite-borne Ka-band antenna comprising a parabolic primary reflector and a secondary reflector disposed above the primary reflector. A support member is disposed between the primary and secondary reflectors. A feed is disposed through the center of the primary reflector. A waveguide is disposed below the feed, with a port for signal input. This miniaturized satellite-borne Ka-band antenna is compact, lightweight, structurally reliable, and exhibits high gain. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is an exploded schematic diagram of an embodiment of a miniaturized satellite-borne Ka-band antenna according to the present invention;

[0017] Figure 2 yes Figure 1 Schematic diagram of assembly of the embodiment shown;

[0018] Figure 3 is a cross-sectional view of the interior of a waveguide in another embodiment of the miniaturized spaceborne Ka-band antenna of the present invention;

[0019] Figure 4is a longitudinal cross-sectional view of a sub-reflector in another embodiment of the miniaturized spaceborne Ka-band antenna of the present invention;

[0020] Figure 5 2. This is a cross-sectional view of a feed source in another embodiment of the miniaturized spaceborne Ka-band antenna of the present invention;

[0021] Figure 6 This is a side view of the positional relationship between the main reflector, sub-reflector and feed source in another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention. DETAILED DESCRIPTION

[0022] To facilitate understanding of the present invention, the present invention will be described in more detail below with reference to the accompanying drawings and specific embodiments. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0023] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0024] Figure 1 This is an exploded schematic diagram of an embodiment of a miniaturized satellite-borne Ka-band antenna according to the present invention. Figure 2 yes Figure 1 The assembly diagram of the embodiment shown is as follows, Figure 3 This is a cross-sectional view of the inner portion of the waveguide in another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention. Figure 4 FIG1 is a longitudinal cross-sectional view of the secondary reflector of another embodiment of the miniaturized spaceborne Ka-band antenna of the present invention. Figure 5 1 is a cross-sectional view of a feed source in another embodiment of a miniaturized spaceborne Ka-band antenna according to the present invention. Figure 6 This is a side view of the positional relationship between the main reflector, sub-reflector and feed source in another embodiment of the miniaturized satellite-borne Ka-band antenna of the present invention, combined with Figures 1 to 6 The miniaturized satellite-borne Ka-band antenna includes a parabolic main reflector 1 and a sub-reflector 2 arranged above the main reflector 1, a support is provided between the main reflector 1 and the sub-reflector 2, a feed source 4 is provided through the center of the main reflector 1, a waveguide 5 is further provided at the lower part of the feed source 4, and the waveguide 5 has a port 6 for signal entry.

[0025] Preferably, the port of the waveguide is fed by a single-port 50-ohm probe.

[0026] Preferably, a connector 7 is provided at the port 6 , and the connector 7 has a connector core 71 inserted into the port 6 . The connector 7 is SMA-50K, and its characteristic impedance is 50 ohms. The connector 7 can be fixed to the waveguide 5 by a screw L1 .

[0027] Preferably, the support member includes a support column 3 for fixing the secondary reflector 2 to the main reflector 1, the upper end of the support column 3 is connected to the secondary reflector 2, and the lower end of the support column 3 is connected to the main reflector 1. The length and number of the support columns 3 are not fixed. In this embodiment, there are four support columns 3 and they are evenly arranged. The support columns 3 are arranged around the feed source 4, and screw holes are opened on the upper and lower end faces of the support columns 3. Screw holes are also opened at positions corresponding to the main reflector 1 and the secondary reflector 2. The main reflector 1, the secondary reflector 2 and the support columns 3 are connected by screws.

[0028] Further preferably, a plurality of grooves 11 are provided on the bottom surface of the main reflecting surface 1 , the shape of the grooves 11 is adapted to the cross-sectional shape of the support column 3 , and a through hole is provided at the center of the grooves 11 for connecting the support column 3 .

[0029] Further preferably, a cavity 51 is opened inside the waveguide 5, and the cavity 51 is connected to the port 6. The cavity 51 is divided into a first cavity 511 and a second cavity 512 starting from the port 6. The first cavity 511 and the second cavity 512 converge at the output portion 52 of the cavity 51. The first cavity 511 and the second cavity 512 have a length difference in the path. The output portion 52 is connected to the feed source 4. The signal entering the port 6 enters the first cavity 511 and the second cavity 512 in two paths. The two signals converge at the output portion 52 and generate a 90° phase difference, forming circular polarization for outward radiation.

[0030] Further preferably, the cavity 51 is a blind groove, that is, the cavity 51 is downwardly connected to the outside, and a waveguide chassis 8 can be provided under the waveguide 5 to cover the bottom end of the waveguide 5 to prevent the cavity 51 from being exposed.

[0031] Further preferably, a plurality of fixing holes D1 are provided on the waveguide chassis 8 and the waveguide 5 for fixedly connecting the waveguide chassis 8 and the waveguide 5 .

[0032] Further preferably, the cavity 51 is a U-shaped cavity, and the port 6 is connected to the cavity 51 via a transmission cavity 61 , which is a linear cavity.

[0033] Further preferably, a protrusion Q1 is provided at the connection point between the transmission cavity 61 and the cavity 51, and the cavity width at the position of the protrusion Q1 is smaller than the cavity width at other positions, and the cavity width on both sides of the protrusion Q1 gradually increases as it moves away from the protrusion Q1.

[0034] Further preferably, when the miniaturized satellite-borne Ka-band antenna is working, the signal enters from the port 6, is divided into two signals through the waveguide 5 for transmission, and the two signals will produce a 90° phase difference when reaching the feed source, and then form circularly polarized radiation through the feed source, and the radiated radiation pattern is a directional radiation pattern.

[0035] Preferably, a circular boss 53 is provided on the waveguide 5, and the circular boss 53 is used to be connected to the main reflecting surface 1. The lower end of the main reflecting surface 1 is provided with a connecting portion whose shape is adapted to the shape of the circular boss 53. A plurality of corresponding connecting holes 12 are provided on the connecting portion and the circular boss 53, and the connecting portion and the circular boss 53 are fixedly connected through the connecting holes 12.

[0036] Preferably, the feed source 4 includes a conductive portion 41 and a horn 42 that are interconnected. The conductive portion 41 is connected to the output portion 52 of the cavity 51. The horn 42 is located on the primary reflector 1. The conductive portion 41 supplies signals and energy and has shielding properties. The cross-section of the conductive portion 41 is rectangular. This feed source provides minimal obstruction to the primary reflector, providing good matching. It simultaneously feeds energy and provides effective illumination, organizing electromagnetic waves reflected from the primary and secondary reflectors.

[0037] Further preferably, a feed hole 13 for inserting the feed source 4 is provided in the center of the main reflecting surface 1, and the shape of the feed hole 13 is adapted to the shape of the conductive portion 41. The horn 42 extends outward from the terminal end of the conductive portion 41, and the aperture of the horn 42 gradually increases. Specifically, the inner wall of the horn 42 is a slope 421, and the opening surrounded by the slope 421 faces the secondary reflecting surface 2, and the aperture of the opening gradually increases as the opening approaches the secondary reflecting surface 2, and the cross-section of the aperture is rectangular.

[0038] Preferably, the lower end surface 422 of the speaker 42 is in contact with the main reflecting surface 1, and a through hole 4221 is provided on the lower end surface 422, and a through hole 14 is provided on the main reflecting surface 1 corresponding to the position of the through hole 4221, and the speaker 42 can be connected to the main reflecting surface 1 by screws.

[0039] Preferably, the feed source 4 is a pyramidal horn antenna, which forms circular polarization through waveguide dual feeding, has an aperture of 15mm×15mm (excluding wall thickness) and a height of 31mm. The pyramidal horn antenna has a large aperture diameter, a long length, and a high gain. At the same time, it has a simple structure, a wide bandwidth, a large power capacity, and is easy to adjust and use.

[0040] Further preferably, the feed source can be replaced with a conical horn (emitting linearly polarized waves), a variable angle horn or a corrugated horn (the inner wall of the horn is embedded with corrugated grooves, the feed beam is narrow, it is easy to reduce overflow loss, and it is also easy to adjust the position of the feed source).

[0041] Preferably, the sub-reflecting surface 2 is arranged directly above the feed source 4, and the lower surface of the sub-reflecting surface 2 faces the feed source 4. The lower surface of the sub-reflecting surface 2 has an elliptical surface 21 generated around the central axis of the sub-reflecting surface 2, which is convenient for reflecting the signal.

[0042] Further preferably, the lower surface of the secondary reflector 2 is further provided with a groove 22 for the support member to be embedded in, and a threaded hole 221 is provided in the groove, so that the upper end of the support member can be embedded in the groove 22 and then the support member and the secondary reflector can be threadedly fastened with screws.

[0043] Preferably, the secondary reflector 2 is circular, the diameter of the circle formed by the focus of the primary reflector 1 is the same as the diameter of the secondary reflector 2 , and the circle formed by the focus of the primary reflector 1 corresponds to the position of the secondary reflector 2 in the upper and lower directions.

[0044] Preferably, the electromagnetic wave is first reflected by the sub-reflector 2 to the main reflector 1, and then reflected by the main reflector 1 to space, forming a directional high-gain radiation pattern. From the elliptical and parabolic characteristics, it can be seen that the path of the signal radiated by the feed source after being reflected twice by the main reflector 1 and the sub-reflector 2 is: the phase center of the feed source 4 coincides with one focus of the sub-reflector 2, the signal formed by the reflection of the feed source radiated by the sub-reflector 2 will pass through the other focus of the sub-reflector 2, the focus of the main reflector 1 coincides with the other focus of the sub-reflector 2, and the signal formed by the reflection of the sub-reflector 2 will be reflected by the main reflector 1 and will be directionally emitted parallel to the main axis of the miniaturized satellite-borne Ka-band antenna, thereby forming a directional high-gain radiation pattern.

[0045] Preferably, the elliptical surface 21 is composed of an elliptical arc CB rotating around the axis OC of the main reflector. The phase center of the feed source 4 is located on a focus M of the secondary reflector. The radio waves radiated by the feed source are reflected by the secondary reflector 2 and converge at another focus M' of the elliptical surface 21. At the same time, M' is also the focus of the parabola AD. Therefore, the radio waves reflected by the main reflector are emitted parallel to the axis OC.

[0046] Since the antenna is a rotating body around a mechanical axis, the focus M' forms a circular ring perpendicular to the antenna axis OC, forming a ring-focus antenna. This form can eliminate the obstruction of the sub-reflector to the radio waves and basically eliminate the reflection of the sub-reflector to the feed source. Therefore, it has the advantage of low side lobes. At the same time, the antenna has high aperture efficiency, small standing wave ratio and wide operating frequency.

[0047] Preferably, the distance between the plane where the upper port of the feed source 4 is located and the lower surface of the secondary reflector 2 is determined by the two foci and the focal length of the elliptical arc CB of the secondary reflector 2. One of the foci of the elliptical surface coincides with the focus of the primary reflector, and the other focus M of the elliptical surface is located at the phase center of the feed source 4. If the phase center of the feed source does not coincide with a focus corresponding to the elliptical arc CB, the electrical performance of the antenna will be affected. The greater the deviation between the phase center and the focus, the greater the impact on the electrical performance of the antenna, and the more serious the deterioration of the antenna gain and the shape of the radiation pattern.

[0048] Further preferably, the distance between the feed source 4 and the sub-reflector 2 can be shortened, which is beneficial to reducing the side lobes and standing wave ratio of the antenna in a wide frequency band and improving the efficiency of the antenna.

[0049] More preferably, the length of the elliptical arc CB may be further appropriately increased, so that the radio wave radiation range of the main reflecting surface 1 is increased, thereby improving the utilization rate of the main reflecting surface 1 .

[0050] More preferably, the arrangement may be performed in a manner of being inclined at 67.5° relative to the surface of the star to improve the effective coverage of the beam.

[0051] Preferably, screws can be used for both the connection holes and the fixing holes of the antenna, and the antenna can be assembled after the screws are coated with thread glue. The thread glue can form a strong and tough adhesive film in the thread gap, so that the screws are locked and will not loosen.

[0052] Preferably, the thread glue is DG-4 (blue) modified epoxy adhesive with a temperature resistance of -196°C to 120°C.

[0053] Preferably, the Ka antenna can be made of non-magnetic materials, and the main body of the miniaturized satellite-borne Ka-band antenna is aluminum alloy 7075-T651, polyimide support and stainless steel (screws). Since the two materials are mostly connected by screws, and there is a certain gap between the screw holes and the screws, the stability of the structure can be guaranteed when the temperature drops suddenly.

[0054] Preferably, the maximum diameter of the main reflecting surface is 130 mm, and the maximum diameter of the secondary reflecting surface is 40 mm, with small size and light weight.

[0055] Based on the above embodiments, the present invention discloses a miniaturized spaceborne Ka-band antenna, comprising a parabolic primary reflector and a secondary reflector disposed above the primary reflector. A support member is disposed between the primary and secondary reflectors. A feed is disposed through the center of the primary reflector, and a waveguide is disposed below the feed, with a port for signal input. This miniaturized spaceborne Ka-band antenna features a small size, lightweight, reliable structure, and high gain.

[0056] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's description and drawings, or directly or indirectly applied to other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A miniaturized spaceborne Ka-band antenna, characterized in that: The antenna comprises a parabolic main reflector and a secondary reflector disposed above the main reflector, a support member being disposed between the main reflector and the secondary reflector, a feed source being disposed through the center of the main reflector, a waveguide being disposed below the feed source, and a port being provided on the waveguide for signal entry; the feed source being a pyramidal horn antenna; A cavity is provided inside the waveguide, the cavity is connected to the port, the cavity is divided into a first cavity and a second cavity starting from the port, the first cavity and the second cavity converge at the output portion of the cavity, the first cavity and the second cavity have a length difference in the path, and the output portion is connected to the feed source.

2. The miniaturized spaceborne Ka-band antenna according to claim 1, wherein: The feed source includes a conducting portion and a horn which are connected to each other, the conducting portion is connected to the output portion of the cavity, and the horn is located on the main reflection surface.

3. The miniaturized spaceborne Ka-band antenna according to claim 2, wherein: The secondary reflector is arranged directly above the feed source, with the lower surface of the secondary reflector facing the feed source. The lower surface of the secondary reflector has an elliptical surface generated around the central axis of the secondary reflector.

4. The miniaturized spaceborne Ka-band antenna according to claim 3, wherein: The secondary reflective surface is circular, the diameter of the circle formed by the focus of the primary reflective surface is the same as the diameter of the secondary reflective surface, and the circle formed by the focus of the primary reflective surface corresponds to the secondary reflective surface in vertical position.

5. The miniaturized spaceborne Ka-band antenna according to claim 4, characterized in that: One of the foci of the elliptical surface coincides with the focus of the main reflecting surface, and the other focus of the elliptical surface is located at the phase center of the feed source.

6. The miniaturized spaceborne Ka-band antenna according to claim 5, characterized in that: A feed hole for inserting the feed source is provided in the center of the main reflecting surface. The shape of the feed hole matches the shape of the conducting portion. The horn expands outward from the terminal end of the conducting portion, and the caliber of the horn gradually increases.

7. The miniaturized spaceborne Ka-band antenna according to claim 1, wherein: The maximum diameter of the primary reflective surface is 130 mm, and the maximum diameter of the secondary reflective surface is 40 mm.

8. The miniaturized spaceborne Ka-band antenna according to claim 1, wherein: The support member includes a support column, the upper end of the support column is connected to the secondary reflector, the lower end of the support column is connected to the main reflector, and the support column is arranged around the feed source.

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