Multi-beam antenna based on transmission and reflection

Abstract

The invention belongs to the technical field of antennas, and relates to a multi-beam antenna based on transmission and reflection, which comprises a transmission metasurface, a feed source surface and a reflection metasurface which are sequentially arranged from top to bottom, wherein the transmission metasurface and the feed source surface are arranged at an interval, and the feed source surface abuts against the reflection metasurface; the feed source surface comprises a plurality of feed sources arranged in an array, so that multi-beam scanning is realized by adopting multiple ports; the feed source generates linearly polarized waves to irradiate and transmit the metasurface; the transmission metasurface comprises a plurality of transmission units arranged in an array, and the transmission units perform polarization selection to convert linear polarized waves of the feed source into circularly polarized waves and radiate the circularly polarized waves, or reflect the linear polarized waves of the feed source to the reflection units and convert the linearly polarized waves converted by the reflection units into circularly polarized waves and radiate the circularly polarized waves; the reflection metasurface comprises a plurality of reflection units arranged in an array mode, and the reflection units achieve conversion of linearly polarized waves and reflect the linearly polarized waves to the transmission units. According to the invention, the section height of electromagnetic waves in space can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of antennas, and in particular to a multi-beam antenna based on transmission and reflection. Background Art

[0002] Satellites have the advantages of large communication coverage area and rich communication frequency resources, and are applied in many aspects such as national defense and military, civil communication, aviation and shipping. With the rapid growth of communication service demands, satellite communication has become a major research focus of current space communication technologies. Due to the development of diversified functions and scenarios, the high-standard service demands faced by satellite networks and the user accommodation pressure have also increased. Therefore, how to achieve seamless satellite coverage and improve satellite communication capacity has become one of the research hotspots.

[0003] Due to the rapid growth of service demands such as personal communication, high-speed networks, military communication, and mobile communication, it has also promoted the development of communication satellites towards high-capacity and high-rate directions. As a key data transmission terminal of communication satellites, using a multi-beam scheme is an ideal choice to meet this development demand.

[0004] Currently, the satellite antennas mainly used are reflector antennas and phased array antennas. The former has problems such as large mass, large volume, and high profile. For the latter, the radio frequency multi-beam forming part needs to adjust the beam rotation through phase shifters, which has problems such as complex feed networks, narrow beam scanning, high research and development costs, and large losses. As a new electromagnetic artificial two-dimensional material, metasurface has extraordinary physical properties that natural dielectrics do not possess, and provides more degrees of freedom for electromagnetic wave regulation with its anisotropic characteristics. It is gradually becoming a research hotspot and frontier in multiple interdisciplinary fields. Using metasurfaces to integrate and form metasurface antennas can flexibly adjust the beam, produce antennas with low profile, circular polarization, and multi-beams, have simple feed networks, and have the characteristics of light mass, small volume, low profile, low cost, and easy processing, and are increasingly used in satellite antennas.

[0005] In the prior art, the focus on metasurfaces is mainly on the refraction, reflection of metasurfaces and their regulation effects on antenna arrays such as matching, radiation, and beams. Metasurface antennas are divided into refractive array antennas and reflective array antennas. The gain and aperture efficiency of refractive array antennas are very low. The focusing position of the reflective array antenna and the feed source are on the same side. Therefore, when electromagnetic waves are reflected by the reflective array, the feed source will block the reflected electromagnetic waves, resulting in feed source blockage and causing losses to the incoming waves. Moreover, both of them have high profiles, which is not conducive to integration in microwave circuits. Summary of the Invention

[0006] Based on this, it is necessary to provide a multi-beam antenna based on transmission and reflection for the above technical problems, which can improve the gain and aperture efficiency, balance the gain consistency between multi-beams, avoid feed blockage, and reduce the profile height of electromagnetic waves in space to F / 3, where F is the focal length.

[0007] A multi-beam antenna based on transmission and reflection includes, from top to bottom in sequence: a transmissive metasurface, a feed surface, and a reflective metasurface; wherein, the transmissive metasurface is spaced apart from the feed surface, and the feed surface is in contact with the reflective metasurface. The feed surface includes a plurality of feeds arranged in an array to achieve multi-beam scanning with multiple ports; the feeds generate linearly polarized waves to irradiate the transmissive metasurface. The transmissive metasurface includes a plurality of transmissive units arranged in an array. The transmissive units perform polarization selection, converting the linearly polarized waves of the feeds into circularly polarized waves for radiation, or reflecting the linearly polarized waves of the feeds to the reflective units and converting the linearly polarized waves converted by the reflective units into circularly polarized waves for radiation. The reflective metasurface includes a plurality of reflective units arranged in an array. The reflective units achieve the conversion of linearly polarized waves and reflect them to the transmissive units.

[0008] In one embodiment, the transmissive unit includes, from top to bottom in sequence: an upper transmissive layer, an upper dielectric layer, a ground layer, a lower dielectric layer, and a lower transmissive layer. The upper dielectric layer and the lower dielectric layer are square dielectric layers of the same size. The upper transmissive layer includes: a circular upper patch and a groove provided at the edge of the upper patch; the center of the upper patch coincides with the center of the upper dielectric layer; there are two grooves, which are respectively provided at the positions corresponding to a set of diagonals of the upper dielectric layer. The lower transmissive layer includes: a circular lower patch, the center of the lower patch coincides with the center of the lower dielectric layer, and the radius of the lower patch is equal to the radius of the upper patch. The upper transmissive layer is electrically connected to the lower transmissive layer.

[0009] In one embodiment, a C-shaped slot is provided on both the upper patch and the lower patch. The two C-shaped slots are exactly the same, and the perimeter of the C-shaped slot is half of the wavelength of the electromagnetic wave.

[0010] In one embodiment, the open end of the C-shaped slot faces one side of the upper dielectric layer or one side of the lower dielectric layer.

[0011] In one embodiment, the transmissive unit further includes: a connecting column. Both ends of the connecting column are perpendicularly connected to the upper transmissive layer and the lower transmissive layer respectively. In one embodiment, the phase of the transmission unit satisfies:

[0012]

[0013]

[0014] wherein is the phase of the transmission unit, is the compensation phase of the first focus, is the compensation phase of the second focus, is the coordinate of the transmission unit arrangement in the x direction, is the coordinate of the transmission unit arrangement in the y direction, is the coordinate of the focus on the x-axis, is the coordinate of the focus on the y-axis, is the focal length, is the wavelength of the electromagnetic wave in free space.

[0015] In one embodiment, the reflection unit includes, from top to bottom, a reflection layer, an intermediate layer, and a floor layer stacked in sequence; The intermediate layer and the floor layer are square layers of the same size; The reflection layer includes a reflection patch provided at the center of the intermediate layer; the reflection patch is a square structure, and any side of the reflection patch is parallel or perpendicular to any side of the intermediate layer.

[0016] In one embodiment, a first cut groove and a second cut groove are provided on the reflection patch; The first cut groove is a rectangular structure and penetrates the reflection patch along a diagonal of the reflection patch; The second cut groove is a square structure and is vertically provided at the midpoint of the first cut groove.

[0017] In one embodiment, the feed source includes a patch layer and a substrate layer; The patch layer is provided on the upper surface of the substrate layer and includes a first patch and a second patch; The first patch is a square structure and is provided at the center of the substrate layer; The second patch is a square ring structure, the inner ring of the square ring structure is equidistantly arranged from the edge of the square structure, and the outer ring of the square ring structure coincides with the edge of the substrate layer; The second patch is connected to the floor layer of the reflection unit.

[0018] In one embodiment, it further includes: a plurality of support columns; The support column is made of a non-metallic material. The top of the support column is connected to the transmissive metasurface, and the middle of the support column is connected to the reflective metasurface.

[0019] The above multi-beam antenna based on transmission and reflection is a folded metasurface antenna, which has the following beneficial effects: 1) It can fold the electromagnetic waves generated by the feed multiple times between the transmissive metasurface and the reflective metasurface, effectively reducing the profile height, so that the profile height of the electromagnetic waves in space is reduced to F / 3, where F is the height of the focus, and it can be effectively integrated into the microwave circuit; 2) The feed and the focus of the transmissive metasurface are located on both sides of the metasurface. The electromagnetic waves emitted by the feed will not cause energy loss due to feed blockage, solving the problem of feed blockage; 3) Using dual foci or triple foci to compensate for the phase to achieve antenna focusing, effectively reducing the gain difference between the normal beam and other beams, reducing the gain loss of multi-beams, and being able to maintain the gain consistency between beams, which is beneficial to the stability of communication; 4) It can be used as a spaceborne antenna. By using a passive structure and multi-port feed common aperture, beam deflection can be achieved, thus realizing multi-beam scanning, without a complex feed structure, and being beneficial to improving the gain of the feed at both ends of the port, reducing the gain loss, and having high radiation efficiency; 5) The linearly polarized feed combined with the dielectric integrated waveguide and the connecting column forms a metal cavity, which can effectively improve the isolation between the feeds and reduce the coupling effect between the feeds; 6) Converting the linearly polarized wave generated by a simple linearly polarized feed into a circularly polarized wave can resist multipath reflection, achieve efficient conversion of linear and circular polarization, and effectively reduce the polarization interference in the communication transmission process, improving the anti-interference ability. Description of the Drawings

[0020] Figure 1 It is a three-dimensional schematic diagram of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 2 It is a schematic diagram of the transmission unit of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 3 It is a schematic diagram of the upper transmission layer of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 4 It is a schematic diagram of the lower transmission layer of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 5 It is a schematic diagram of the feed of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 6 It is a schematic diagram of the reflection unit of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 7 Top view of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 8 Bottom view of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 9 One of the size diagrams of the transmission unit of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 10 Another size diagram of the transmission unit of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 11 Simulation diagram of the magnitude of the transmission coefficient of the transmission unit of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 12 Simulation diagram of the phase of the transmission coefficient of the transmission unit of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 13 Size diagram of the reflection unit of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 14 Simulation diagram of the reflection coefficient of the reflection unit of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 15 Size diagram of the feed of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 16 Simulation diagram of S11 of the surface of the feed of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 17 Simulation diagram of the surface gain of the feed of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 18 3D beam pattern of port1 of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 19 2D beam pattern of port1 of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 20 3D beam pattern of port9 of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 21 2D beam pattern of port9 of a multi-beam antenna based on transmission and reflection in an embodiment; Figure 22 S-parameter schematic diagram of a multi-beam antenna based on transmission and reflection in an embodiment.

[0021] Reference numerals: Transmissive metasurface 1, upper transmissive layer 11, upper patch 111, groove 112, upper C-shaped groove 113, upper dielectric layer 12, ground layer 13, lower dielectric layer 14, lower transmissive layer 15, lower patch 151, lower C-shaped groove 152, connecting post 16; Feeder surface 2, patch layer 21, first patch 211, second patch 212, substrate layer 22, connecting post 23; Reflective metasurface 3, reflective layer 31, reflective patch 311, first cut groove 312, second cut groove 313, intermediate layer 32, floor layer 33; Support post 4; Coaxial feeding port 5. Detailed implementation manners

[0022] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0023] It should be noted that all directional indications (such as up, down, left, right, front, back,...) in the embodiments of the present application are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0024] In addition, in the present application, descriptions such as "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "multiple groups" is at least two groups, such as two groups, three groups, etc., unless otherwise specifically defined.

[0025] In the present application, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0026] In addition, the technical solutions between the various embodiments of the present application can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0027] The present application provides a multi-beam antenna based on transmission and reflection. As Figure 1 shown, in one embodiment, it includes: a transmissive metasurface, a feed surface, a reflective metasurface, and a plurality of support columns. Among them, the transmissive metasurface, the feed surface, and the reflective metasurface are arranged in sequence from top to bottom. The transmissive metasurface is spaced from the feed surface, and the feed surface is in contact with the reflective metasurface (that is: the feed surface is provided on the upper surface of the reflective metasurface).

[0028] I. Transmissive metasurface The transmissive metasurface includes a plurality of transmissive units arranged in an array; the transmissive units achieve polarization selection and the conversion between linear and circular polarization, that is, after polarization selection, the linear polarization wave of the feed is converted into a circular polarization wave and radiated out, or the linear polarization wave of the feed is reflected to the reflective unit and the converted linear polarization wave of the reflective unit is converted into a circular polarization wave and radiated out; different transmissive units have different electromagnetic wave phases to generate different deflection angles, generate multi-beams, and achieve beam scanning.

[0029] As Figure 2 shown, the transmissive unit includes: an upper transmissive layer, an upper dielectric layer, a ground layer, a lower dielectric layer, a lower transmissive layer, and a connecting column. Among them, the upper transmissive layer, the upper dielectric layer, the ground layer, the lower dielectric layer, and the lower transmissive layer are stacked in sequence from top to bottom.

[0030] As Figure 3 shown, the upper transmissive layer includes: an upper patch, two grooves, and an upper C-shaped slot. The upper patch is a circular structure, and the center of the circle coincides with the center of the upper dielectric layer; the two grooves are both provided at the edge of the upper patch and are respectively provided at the positions of a set of diagonals of the corresponding upper dielectric layer to generate circular polarization; the perimeter of the upper C-shaped slot is half of the wavelength of the electromagnetic wave (the inner and outer rings of the upper C-shaped slot are of equal length) to expand the bandwidth, and the open end of the upper C-shaped slot faces one side of the upper dielectric layer to ensure both good circular polarization and good bandwidth at the same time.

[0031] The upper dielectric layer is a support layer for loading the upper transmissive layer; the upper dielectric layer is a square dielectric layer.

[0032] An isolation through hole is provided on the ground layer so that the connecting column passes through the isolation through hole and is connected to the upper transmissive layer and the lower transmissive layer, and the connecting column is spaced from the ground layer to achieve isolation between the connecting column and the ground layer.

[0033] The lower dielectric layer is a support layer for loading the lower transmission layer; the lower dielectric layer is a square dielectric layer and is the same size as the upper dielectric layer.

[0034] As Figure 4 shown, the lower transmission layer includes: a lower patch and a lower C-shaped slot. The lower patch is a circular structure, the center of the circle coincides with the center of the lower dielectric layer, and the radius of the lower patch is equal to the radius of the upper patch; the lower C-shaped slot is exactly the same as the upper C-shaped slot, that is to say, the perimeter of the lower C-shaped slot is also half the wavelength of the electromagnetic wave (the inner ring and the outer ring of the lower C-shaped slot are of equal length), the open end of the lower C-shaped slot faces one side of the lower dielectric layer, and the upper C-shaped slot and the lower C-shaped slot are vertically aligned (if the opening faces the x direction, only the x-linearly polarized wave can be received, if the opening faces the y direction, only the y-linearly polarized wave can be received, thus realizing polarization selection).

[0035] The connecting column is a cylindrical structure, one end is vertically connected to the upper transmission layer, and the other end is vertically connected to the lower transmission layer to electrically connect the upper transmission layer and the lower transmission layer.

[0036] II. Feed Source Surface The feed source surface includes a plurality of feed sources arranged in an array to achieve multi-beam scanning using multiple ports. At the same time, the phase delays of the electromagnetic waves irradiated on the transmission metasurface are different, causing the electromagnetic waves transmitted through the metasurface to deflect at different angles, realizing the deflection of different beams; the feed source generates linearly polarized waves to irradiate the transmission units of the transmission metasurface; the feed source surface adopts a SIW structure (substrate integrated waveguide), which is beneficial to effectively reduce the energy coupling interference between ports during integration and reduce the isolation degree.

[0037] As Figure 5 shown, the feed source includes: a patch layer and a substrate layer. Among them, the patch layer is arranged on the upper surface of the substrate layer.

[0038] The patch layer includes: a first patch and a second patch. The first patch is a square structure and is arranged at the center of the substrate layer; the second patch is a square ring structure, the inner ring of the square ring structure is arranged at an equal interval from the edge of the square structure, the outer ring of the square ring structure coincides with the edge of the substrate layer, and the center of the square ring structure coincides with the center of the square structure.

[0039] The substrate layer is a support layer for loading the patch layer; the substrate layer is arranged on the upper surface of the reflection metasurface.

[0040] III. Reflection Metasurface The reflection metasurface includes a plurality of reflection units arranged in an array; the reflection units realize the conversion of linearly polarized waves and reflect them to the transmission units.

[0041] The reflection unit includes: a reflection layer, an intermediate layer, and a floor layer. Among them, the reflection layer, the intermediate layer, and the floor layer are stacked in sequence from top to bottom.

[0042] As shown Figure 6 in the figure, the reflection layer includes: a reflection patch, a first cut groove, and a second cut groove. The reflection patch is arranged at the center of the intermediate layer and has a square structure. Any side of the reflection patch is parallel or perpendicular to any side of the intermediate layer to achieve polarization conversion (i.e., convert the x-line polarized wave into a y-line polarized wave, or convert the y-line polarized wave into an x-line polarized wave); the first cut groove is arranged on the reflection patch and has a rectangular structure, and penetrates the reflection patch along a diagonal line of the reflection patch to improve the polarization conversion efficiency; there are two second cut grooves, which are square structures arranged on the reflection patch (the square structure is formed by a rectangular structure that is vertically arranged at the midpoint of the first cut groove and recessed away from the first cut groove), and the side length of the second cut groove is greater than the width of the first cut groove to further improve the polarization conversion efficiency.

[0043] The intermediate layer is a support layer for loading the reflection layer; the intermediate layer is a square layer.

[0044] The floor layer is a square layer and has the same size as the intermediate layer.

[0045] IV. Support posts The support posts are made of non-metallic materials. The top of the support posts is connected to the transmissive metasurface, and the middle part of the support posts is connected to the reflective metasurface, so that the transmissive metasurface, the reflective metasurface, and the feed surface arranged on the reflective metasurface are all spaced apart, thereby improving the focusing effect, generating multiple beams, reducing the profile, while ensuring the polarization conversion efficiency and avoiding increasing the tilt angle due to multiple reflections.

[0046] In this embodiment, the second patch of the feed is connected to the floor layer of the reflection unit, so that the feed and the reflection unit are integrated together and share the floor layer. Specifically: the feed further includes a plurality of connecting columns; the plurality of connecting columns are spaced apart and enclose a square structure spaced apart from the first patch; one corresponding end of the plurality of connecting columns is connected to the second patch, and the other corresponding end is connected to the floor layer; the connecting columns can be metal through holes; the connecting columns and the second patch work together to improve the S parameters and isolation, and prevent the reduction of radiation efficiency caused by mutual coupling.

[0047] It should be noted that: a coaxial feed port is also provided on the antenna. The coaxial feed port includes an inner conductor and an outer conductor. The inner conductor is connected to the first patch of the feed, and the outer conductor is connected to the floor layer of the reflection unit.

[0048] Preferably, the phase of the transmissive unit satisfies the following formula to perform phase compensation on the incoming wave, achieve dual-focus focusing, thereby taking into account all beams, improving the gain loss between the beams, reducing the gain difference of beam scanning, and improving the gain consistency and stability between the beams;

[0049]

[0050]

[0051] In the formula, is the compensation phase of the double focus of the transmission unit, is the compensation phase of the first focus, is the compensation phase of the second focus, is the coordinate of the transmission unit arrangement in the x direction, is the coordinate of the transmission unit arrangement in the y direction, is the coordinate of the focus on the x-axis, is the coordinate of the focus on the y-axis, is the focal length, is the wavelength of the electromagnetic wave in free space.

[0052] Further preferably, the phase of the transmission unit satisfies the following formula to perform phase compensation on the incoming wave, achieve three-focus focusing, thereby further taking into account all beams, further improving the gain loss between beams, further reducing the gain difference of beam scanning, and further improving the gain consistency and stability between beams, and further increasing the gain, thereby increasing the aperture efficiency;

[0053]

[0054]

[0055]

[0056] In the formula, is the compensation phase of the three foci of the transmission unit, is the compensation phase of the first focus, is the compensation phase of the second focus, is the compensation phase of the third focus, is the coordinate of the transmission unit arrangement in the x direction, is the coordinate of the transmission unit arrangement in the y direction, is the coordinate of the focus on the x-axis, is the coordinate of the focus on the y-axis, is the focal length, is the wavelength of the electromagnetic wave in free space.

[0057] Even more preferably, the area of the transmissive metasurface is the same as that of the reflective metasurface, but the number of transmission units is different from the number of reflection units to improve the gain and axial ratio.

[0058] Further preferably, the transmission units form a rectangular array to be combined with the feed surface, ensuring sufficient radiation of each transmission unit and improving the aperture efficiency.

[0059] Further preferably, the number of feeds is nine to avoid an increase in coupling between feed ports and a decrease in the number of beams, effectively maintaining multiple beams and high gain, and balancing gain, aperture efficiency, and isolation to ensure antenna performance.

[0060] The working process of this embodiment is as follows: The feed generates an x - polarized wave and irradiates the lower transmission layer of the transmission unit on the transmission metasurface; the transmission metasurface does not absorb the x - polarized wave and reflects the x - polarized wave to the reflection metasurface; the reflection layer of the reflection unit on the reflection metasurface converts the x - polarized wave into a y - polarized wave and reflects the y - polarized wave to the transmission metasurface; the lower transmission layer of the transmission unit on the transmission metasurface absorbs the y - polarized wave, transfers the y - polarized wave along the connecting column to the upper transmission layer, and the upper transmission layer converts the y - polarized wave into a circularly polarized wave and radiates it out; Or, the feed generates a y - polarized wave and irradiates the lower transmission layer of the transmission unit on the transmission metasurface; the lower transmission layer of the transmission unit on the transmission metasurface absorbs the y - polarized wave, transfers the y - polarized wave along the connecting column to the upper transmission layer, and the upper transmission layer converts the y - polarized wave into a circularly polarized wave and radiates it out.

[0061] The above multi - beam antenna based on transmission and reflection is a folded metasurface antenna and has the following beneficial effects: 1) It can fold the electromagnetic wave generated by the feed multiple times between the transmission metasurface and the reflection metasurface, effectively reducing the profile height, so that the profile height of the electromagnetic wave in space is reduced to F / 3, where F is the height of the focus, and it can be effectively integrated into the microwave circuit; 2) The feed and the focus of the transmission metasurface are on both sides of the metasurface, and the electromagnetic wave emitted by the feed will not cause energy loss due to feed blockage, solving the problem of feed blockage; 3) Using two or three foci to compensate for the phase to achieve antenna focusing, effectively reducing the gain difference between the normal beam and other beams, reducing the gain loss of multiple beams, being able to maintain the gain consistency between beams, and improving gain and aperture efficiency, which is beneficial to the stability of communication; 4) It can be used as a spaceborne antenna. By using a passive structure and multi - port feed common aperture, beam deflection can be achieved, thus realizing multi - beam scanning without a complex feed structure, and being beneficial to improving the gain of the feed at both ends, reducing gain loss, and having high radiation efficiency; 5) The linearly polarized feed combined with the dielectric integrated waveguide and the connecting column forms a metal cavity, which can effectively improve the isolation between feeds and reduce the coupling between feeds; 6) Convert the linearly polarized wave generated by a simple linearly polarized feed into a circularly polarized wave, which can resist multipath reflection, achieve efficient conversion between linear and circular polarization, and effectively reduce polarization interference during communication transmission, improving the anti-interference ability.

[0062] In a specific embodiment, as Figure 7 shown, the transmissive metasurface includes 20 * 16 transmissive units (the angles of different transmissive units are different). In the transmissive unit, the thicknesses of the upper transmissive layer, the ground layer, and the lower transmissive layer are all 0.035 mm; the thicknesses of the upper dielectric layer and the lower dielectric layer are 0.787 mm, and the material used is Rogers 5880, and the loss tangent of the material is 0.0009. The reflective metasurface includes 20 * 20 reflective units (the angles of different reflective units are the same). In the reflective unit, the thicknesses of the reflective layer and the floor layer are both 0.035 mm; the thickness of the intermediate layer is 0.787 mm, and the material used is Rogers 5880, and the loss tangent of the material is 0.0009. As Figure 8 shown, there are nine feeds on the feed surface, and nine pencil beams are realized by using 9 feed ports (respectively: Port1, Port2, Port3, Port4, Port5, Port6, Port7, Port8, Port9). Among them, the distances between the feed ports are equal, so the deflection angles between the feed ports are all 7°. Port1 is 0°, Port2 is 7°, Port3 is 14°, Port4 is 21°, Port5 is 28°, Port6 is 7°, Port7 is 14°, Port8 is 21°, Port9 is 28°, and good gain consistency is ensured. There are four support columns, made of nylon material.

[0063] As Figure 9 and Figure 10 shown in the size diagram of the transmissive unit (the width m of the groove is 1.8 mm, the depth of the groove is 0.41 mm, the inner ring diameter d1 of the upper C-shaped groove or the lower C-shaped groove is 1.8 mm, the diameter d2 of the upper patch or the lower patch is 2.04 mm, the opening distance J of the upper C-shaped groove or the lower C-shaped groove is 1.6 mm, the width i of the upper C-shaped groove or the lower C-shaped groove is 0.25 mm, and the side length p of the upper dielectric layer or the lower dielectric layer is 5 mm), the function of converting x polarization to right-handed circular polarization can be realized. Simulate the above transmissive unit. As Figure 11 shown in the amplitude simulation diagram of the transmissive coefficient of the transmissive unit, as Figure 12 shown in the phase simulation diagram of the transmissive coefficient of the transmissive unit, it can be seen that within the frequency range of 25.5 GHz to 29 GHz, a polarization conversion efficiency of more than -1 dB can be achieved, and the phase compensation condition is also satisfied, so as to facilitate subsequent phase compensation to achieve the compensation of the double focus.

[0064] AsFigure 13 The size diagram of the reflection unit shown (the length a of the middle layer = 5 mm, the width b of the middle layer = 5 mm, the length c of the reflection patch = 3.25 mm, the width d of the reflection patch = 3.25 mm, the width e of the first cut groove = 0.35 mm, the width f of the second cut groove = 0.35 mm, where the second cut groove is a square structure) can achieve the conversion of linearly polarized waves. The above reflection unit is simulated. As Figure 14 The simulation diagram of the reflection coefficient of the reflection unit shown, SZmax(1), Zmax(1) is S11, which represents the reflection efficiency of the y-polarized wave finally reflected as the y-polarized wave on the unit structure. In the range of 24 GHz to 32 GHz, S11 ≤ -10 dB means that the reflection efficiency is very low and the y-polarized wave is completely absorbed; SZmax(2), Zmax(1) is S21, which represents the reflection efficiency of the y-polarized wave finally reflected as the x-polarized wave on the unit structure. In the range of 24 GHz to 32 GHz, S21 being close to 0 dB means that the reflection efficiency is very high and the y-polarized wave is completely absorbed and converted into the x-polarized wave; SZmax(1), Zmax(2) is S12, which represents the reflection efficiency of the x-polarized wave finally reflected as the y-polarized wave on the unit structure. In the range of 24 GHz to 32 GHz, S12 being close to 0 dB means that the reflection efficiency is very high and the y-polarized wave is completely absorbed and converted into the x-polarized wave; SZmax(2), Zmax2) is S22, which represents the reflection efficiency of the x-polarized wave finally reflected as the x-polarized wave on the unit structure. In the range of 24 GHz to 32 GHz, S22 ≤ -10 dB means that the reflection efficiency is very low and the x-polarized wave is completely absorbed. It can be seen that in the frequency range of 24 GHz to 30 GHz, the amplitude of the reflection coefficient is close to 0 dB, and the reflection unit completely converts the incoming linearly polarized wave with a high conversion efficiency.

[0065] As Figure 15 The size diagram of the feed shown (the side length k1 of the first patch = 3.16 mm, the inner ring side length k2 of the second patch = 5 mm, the center distance k4 of the connecting columns = 0.5 mm, the diameter k5 of the connecting columns = 0.34 mm, the side length of the feed (also the outer ring side length of the second patch) k6 = 7 mm, the thickness k7 of the substrate layer = 0.79 mm, the inner conductor diameter of the coaxial feed port is 0.35 mm). The above feeds are combined into the feed surface and simulated. As Figure 16 The S11 simulation diagram of the feed surface shown, as Figure 17 The gain simulation diagram of the feed surface shown. It can be seen that the return loss bandwidth (S11 < -10 dB) is 26.3 GHz to 28.5 GHz, and the gain is 7.12 dBi.

[0066] The antenna is automatically programmed by CST to achieve a dual-focus structure with dimensions of length 110 mm × width 90 mm × height 13.3 mm, and the electrical size of the cross-sectional height is 1.15 λ( λ is the wavelength in free space), with a low profile height and is easy to integrate into microwave circuits.

[0067] As Figure 18 shown in the beam pattern of antenna port1 (the first feed, located at the midpoint of the feed surface), it can be seen that when theta = 0 degrees, the gain of the antenna is 23.21 dBi.

[0068] As Figure 19 shown in the beam pattern of antenna port9 (the ninth feed, located at the edge of the feed surface, specifically the rightmost end of the feed surface in Figure 8 ), it can be seen that when theta = 28 degrees, the gain of the antenna is 19.78 dBi.

[0069] As Figure 20 shown in the schematic diagram of the S-parameters of the antenna, the band of the S-parameters is 26.4 GHz to 28.6 GHz, with a relative bandwidth of 7.8% (S11 < -10 dB), the isolation of each port is less than -23 dB, realizing multi-beam deflection of 9 beams, the gain loss is 3.43 dBi, the range of the deflection angle is -28° to 28°, realizing a relatively wide angle of deflection, and the aperture efficiency is 25%, achieving a relatively high aperture efficiency.

[0070] The content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0071] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0072] The above-described embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A multi-beam antenna based on transmission and reflection, characterized in that: The invention comprises: a transmission metasurface, a feed surface and a reflection metasurface which are arranged in sequence from top to bottom; wherein the transmission metasurface is spaced apart from the feed surface, and the feed surface is abutted against the reflection metasurface; The feed surface includes a plurality of feeds arranged in an array to realize multi-beam scanning using multiple ports; the feed generates a linearly polarized wave to illuminate the transmission metasurface; The transmission metasurface includes a plurality of transmission units arranged in an array, and the transmission units perform polarization selection, convert the linear polarization wave of the feed source into a circular polarization wave for radiation, or reflect the linear polarization wave of the feed source to the reflection unit and convert the linear polarization wave converted by the reflection unit into a circular polarization wave for radiation; The reflective metasurface includes a plurality of reflective units arranged in an array, and the reflective units realize the conversion of linear polarized waves and reflect them to the transmission units.

2. A multi-beam antenna based on transmission and reflection according to claim 1, characterized in that: The transmission unit comprises: an upper transmission layer, an upper dielectric layer, a ground layer, a lower dielectric layer and a lower transmission layer stacked in sequence from top to bottom; The upper dielectric layer and the lower dielectric layer are square dielectric layers of equal size; The upper transmission layer comprises: a circular upper patch and a groove arranged at the edge of the upper patch; the center of the circle of the upper patch coincides with the center of the upper dielectric layer; there are two grooves, which are arranged at a group of diagonal positions corresponding to the upper dielectric layer; The lower transmission layer comprises: a circular lower patch, the center of which coincides with the center of the lower dielectric layer, and the radius of which is equal to the radius of the upper patch; The upper transmission layer is electrically connected to the lower transmission layer.

3. A multi-beam antenna based on transmission and reflection according to claim 2, characterized in that: A C-shaped groove is provided on each of the upper patch and the lower patch. The two C-shaped grooves are completely identical, and the circumference of the C-shaped groove is half the wavelength of the electromagnetic wave.

4. The multi-beam antenna based on transmission and reflection according to claim 3, characterized in that: The opening end of the C-shaped groove faces one edge of the upper dielectric layer or one edge of the lower dielectric layer.

5. The multi-beam antenna based on transmission and reflection according to claim 4, characterized in that: The transmission unit further includes: a connecting column; Two ends of the connection column are respectively vertically connected to the upper transmission layer and the lower transmission layer.

6. A multi-beam antenna based on transmission and reflection according to any one of claims 1 to 5, characterized in that: The phase of the transmission unit satisfies: In the formula, is the phase of the transmission unit, is the compensation phase of the first focus, is the compensation phase of the second focus, Arrange the x-coordinates for the transmission unit, Arrange the y-direction coordinates for the transmission unit, is the coordinate of the focus on the x-axis, is the coordinate of the focus on the y-axis, is the focal length, is the wavelength of the electromagnetic wave in free space.

7. A multi-beam antenna based on transmission and reflection according to any one of claims 1 to 5, characterized in that: The reflection unit comprises: a reflection layer, an intermediate layer and a floor layer stacked in sequence from top to bottom; The middle layer and the floor layer are square layers of equal size; The reflective layer comprises: a reflective patch arranged at the center of the middle layer; the reflective patch is a square structure, and any side of the reflective patch is parallel or perpendicular to any side of the middle layer.

8. The multi-beam antenna based on transmission and reflection according to claim 7, characterized in that: The reflective patch is provided with a first groove and a second groove; The first slot is a rectangular structure and penetrates the reflective patch along a diagonal line of the reflective patch; The second slot is a square structure and is vertically arranged at the midpoint of the first slot.

9. A multi-beam antenna based on transmission and reflection according to any one of claims 1 to 5, characterized in that: The feed source comprises: a patch layer and a substrate layer; The patch layer is arranged on the upper surface of the substrate layer, and includes: a first patch and a second patch; The first patch is a square structure and is arranged at the center of the substrate layer; The second patch is a square ring structure, the inner ring of the square ring structure is arranged at equal intervals from the edge of the square structure, and the outer ring of the square ring structure coincides with the edge of the substrate layer; The second patch is connected to the floor layer of the reflection unit.

10. A multi-beam antenna based on transmission and reflection according to any one of claims 1 to 5, characterized in that: Also includes: Multiple support columns; The support column is made of non-metallic material, the top of the support column is connected to the transmission metasurface, and the middle of the support column is connected to the reflection metasurface.

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