Ku-band antenna array for drone communications

Abstract

The present invention discloses a Ku-band antenna array for drone communications, relating to the field of antenna design. The antenna array comprises a plurality of metasurface antenna units, wherein the metasurface antenna units comprise a metasurface layer and an SIW waveguide layer; a rectangular patch group arranged in an array with equal spacing is laid on the surface of the metasurface layer, the patch group comprising a first rectangular patch etched with slits in the same direction, a second rectangular patch etched with two short slits facing each other, and a third rectangular patch etched with short slots representing magnetic currents, wherein the second rectangular patch is symmetrical about the third rectangular patch; the SIW waveguide layer is pre-set with short-circuit vias and arrayed metal vias, which are used to couple and excite the characteristic modes of the metasurface layer after connecting the SIW feed layer and the slotted ground layer. The antenna array provided by the present invention is not only compact in structure, but also has broadband, high gain, and excellent directivity, and also has good polarization purity and anti-interference capabilities.

Description

Technical Field

[0001] The present invention relates to the technical field of antenna design, and more particularly to a Ku-band antenna array for unmanned aerial vehicle (UAV) communications. Background Art

[0002] Antennas are core components of radio systems, and their transmission efficiency and performance directly determine the reliability of communication systems. The rapid development of technologies such as drone formation flying, real-time HD video backhaul, and remote control has placed higher demands on antennas for broadband, high gain, low profile, and anti-interference capabilities. Particularly in complex electromagnetic environments and high-speed mobile scenarios, traditional antennas, due to limited high-frequency bandwidth, insufficient gain, and severe sidelobe interference, struggle to meet the stringent requirements of drone formation coordination, HD image transmission, and precise control.

[0003] A metasurface (MTS) is a two-dimensional electromagnetic metamaterial composed of a periodic arrangement of subwavelength units, capable of flexibly controlling the phase, amplitude, and polarization of electromagnetic waves. Metasurface antennas have garnered widespread attention in recent years due to their low profile, lightweight, and highly controllable electromagnetic properties.

[0004] However, the resonant characteristics of traditional metasurface units easily induce multi-order modal coupling, resulting in the appearance of undesirable parasitic resonance peaks within the operating frequency band. Especially when the operating frequency band is extended to millimeter waves, the coupling of surface waves and space waves in the undesirable frequency band will induce strong parasitic radiation, forming out-of-band spurious lobes, significantly reducing the spectral purity. This problem will aggravate inter-system interference in dense spectrum environments, leading to increased bit error rates. This parasitic radiation not only reduces antenna efficiency, but also causes radiation pattern distortion, cross-polarization deterioration, and energy leakage, thereby generating intermodulation interference with navigation and measurement and control signals in adjacent frequency bands, threatening the electromagnetic compatibility of drone formation systems.

[0005] Currently existing designs mainly rely on the bandpass filtering characteristics of the resonant unit and lack an active mechanism to suppress out-of-band radiation.

[0006] In addition, existing metasurface antennas lack an effective modal control mechanism and have limited localized control capabilities over electromagnetic fields, resulting in coupled radiation blind spots in the directional pattern or surface currents easily diffusing along unintended paths, causing energy to dissipate in non-radiative directions, making it difficult to meet the directional beamforming requirements in drone formation scenarios. Summary of the Invention

[0007] In view of this, in order to at least partially solve the above technical problems, the present invention provides a Ku-band antenna array for UAV communication;

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A Ku-band antenna array for unmanned aerial vehicle (UAV) communications, comprising a plurality of metasurface antenna units, each comprising a metasurface layer and a SIW waveguide layer;

[0010] The surface of the metasurface layer is paved with a group of rectangular patches arranged in an array with equal spacing. The patch group includes a first rectangular patch etched with a vertical slit, a second rectangular patch etched with two relatively short vertical slits, and a third rectangular patch etched with a short transverse slot representing a magnetic current, and the second rectangular patch is symmetrical about the third rectangular patch.

[0011] The SIW waveguide layer is preset with short-circuit vias and array metal vias, which are used to connect the SIW feeding layer and the slotted ground layer to couple and excite the characteristic modes of the metasurface layer.

[0012] Preferably, the rectangular patches in the rectangular patch group have the same specifications, and the side lengths and arrangement spacings satisfy the following relationship:

[0013] 3*W p +2*W s =W eq =1.5λ

[0014] Where W p Represents the side length of the rectangular patch, W s Indicates the arrangement spacing, W eq represents the side length of the metasurface layer when it is equivalent to a whole rectangular patch, and λ represents the wavelength of the operating frequency.

[0015] Preferably, the third rectangular patch is located in the center of the rectangular patch group, the first rectangular patches exist in rows, multiple rows of second rectangular patches are symmetrically distributed on the upper and lower sides of the third rectangular patch, and the second rectangular patches are in the same row as the third rectangular patch and are symmetrically distributed on the left and right sides of the third rectangular patch.

[0016] Preferably, the first rectangular patch excites surface current in the y-axis direction and suppresses characteristic modes in other current directions. The second rectangular patch excites surface current in the x-axis direction.

[0017] Preferably, at least one row of first rectangular patches located at the boundary of the super surface layer is transitionally cut using a concave arc at the outer edge.

[0018] Preferably, the arrangement and specifications of the array through holes in the SIW waveguide layer meet the following requirements:

[0019] 20*r≤λ,4*r≥d

[0020] Where r is the through hole radius, d is the center-to-center distance between adjacent through holes, and λ is the wavelength of the operating frequency.

[0021] Preferably, the radius of the short-circuit through hole in the SIW waveguide layer is the same as the radius of the array through hole, and the horizontal spacing between the two short-circuit through holes is less than 4r.

[0022] Preferably, the slot in the slotted ground layer is a funnel-shaped slot, and the slot length is greater than half the operating wavelength.

[0023] Preferably, multiple metasurface antenna units are arranged in an array, and the distance between each metasurface antenna unit is greater than half the working wavelength.

[0024] Preferably, the array of metal through holes forms a primary T-shaped SIW power divider and two secondary T-shaped SIW power dividers located at the ends of the primary T-shaped SIW power divider, and the primary T-shaped SIW power divider has a 180-degree phase difference compensation.

[0025] Preferably, the two-stage T-shaped SIW power divider is loaded with a guide through-hole group for guiding the propagation direction of the electromagnetic wave and constraining the electromagnetic field distribution.

[0026] The present invention provides a Ku-band antenna array for UAV communications, which has the following advantages compared with the prior art:

[0027] 1) By customizing the specifications and spacing of the rectangular patches in the metasurface structure, it is possible to ensure that the mode is excited within the preset frequency band. Furthermore, by directionally etching gaps in the rectangular patches, the mode is selectively excited, coupling interference is reduced, and energy confinement capability is improved. In addition, by making arc cuts on the edges of the metasurface, the present application can significantly improve the mode.

[0028] 2) The SIW structure provided in this application can suppress irrelevant modes, stimulate target modes, and improve coupling efficiency.

[0029] The antenna of the present application has a strong out-of-band suppression effect, effectively suppressing unnecessary parasitic radiation in the non-working frequency band and improving the spectral purity of the system. This feature enables the antenna to reduce interference in high-frequency applications and improve signal stability and reliability; that is, it not only has a compact structure, broadband, high gain and excellent directivity, but also has good polarization purity and anti-interference ability, and can provide stable and reliable performance for drone cluster collaborative communication, high-definition image transmission and precise control. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0031] Figure 1 It is a schematic structural diagram of the Ku-band antenna array of the present invention;

[0032] Figure 2 is a cross-sectional view of a metasurface antenna unit in the Ku-band antenna array of the present invention;

[0033] Figure 3 Schematic diagram of the structure of the metasurface layer in the metasurface antenna unit of the present invention;

[0034] Figure 4 is the MS diagram of the four characteristic modes of the metasurface antenna unit of the present invention;

[0035] Figure 5 Schematic diagram of the surface current of the four characteristic modes of the metasurface antenna unit of the present invention at 12.5 GHz;

[0036] Figure 6 Schematic diagram of the SIW structure in the metasurface antenna unit of the present invention;

[0037] Figure 7 Schematic diagram of the surface current at the input impedance Z11 and Z3 of the metasurface antenna unit of the present invention;

[0038] Figure 8 Schematic diagram of the electric field of the SIW in the metasurface antenna unit of the present invention at half TE110, TE110, TE120, half TE310, mixed TE mode, and TE310 resonance points;

[0039] Figure 9 1 is a graph showing the return loss S11 and gain of the metasurface antenna unit of the present invention;

[0040] Figure 10 is a top view of the Ku-band antenna array of the present invention;

[0041] Figure 11 is a bottom view of the Ku-band antenna array of the present invention;

[0042] Figure 12 1 is a graph showing the return loss S11 and gain of the Ku-band antenna array of the present invention;

[0043] Figure 13 These are the main polarization and cross-polarization patterns of the Ku-band antenna array of the present invention at 12.4 GHz and 12.9 GHz.

[0044] Description of reference numerals:

[0045] 1-metasurface layer, 11-rectangular patch group, 111-rectangular patch, 2-slotted ground layer, 21-funnel-shaped slot, 3-SIW feed layer, 31-50Ω feed line, 4-upper dielectric layer, 5-SIW waveguide layer, 51-array through hole, 52-short-circuit through hole, 53-first-stage T-type SIW power divider, 54-second-stage T-type SIW power divider, 541-guide through hole group. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0047] An embodiment of the present invention discloses a Ku-band antenna array for unmanned aerial vehicle (UAV) communications. By combining a substrate integrated waveguide (SIW) with a metasurface (MTS), this not only ensures efficient signal transmission but also enables flexible beam steering through a precisely designed unit structure.

[0048] In this embodiment, the Ku-band antenna array includes a plurality of metasurface antenna units, each of which includes a metasurface layer and a SIW waveguide layer;

[0049] The surface of the metasurface layer is paved with a group of rectangular patches arranged in an array with equal spacing. The patch group includes a first rectangular patch etched with a vertical slit, a second rectangular patch etched with two relatively short vertical slits, and a third rectangular patch etched with a short transverse slot representing a magnetic current, and the second rectangular patch is symmetrical about the third rectangular patch.

[0050] The SIW waveguide layer is preset with short-circuit vias and array metal vias, which are used to connect the SIW feeding layer and the slotted ground layer to couple and excite the characteristic modes of the metasurface layer.

[0051] The antenna array provided in this application is not only compact in structure, but also has wide bandwidth, high gain, low sidelobe, good out-of-band suppression and modal control effects, and is suitable for the long-range high-speed communication and anti-interference capability requirements of drones.

[0052] Example 1

[0053] Reference Figure 1-Figure 2 , Figure 1 This is a schematic structural diagram of the metasurface antenna unit of this application; Figure 2 is a cross-sectional view of a metasurface antenna unit;

[0054] In this embodiment, the metasurface antenna unit is composed of a metasurface layer 1, an upper dielectric layer 4 and an SIW; the SIW includes a slotted ground layer 2, an SIW waveguide layer 5 and an SIW feeding layer 3.

[0055] In one embodiment,

[0056] The super surface layer 1 optimizes the surface current direction through a specific rectangular patch structure and etched gaps, improves the energy confinement capability, and reduces the coupling blind area. Figure 3 , Figure 3 This is a structural diagram of the supersurface layer. A rectangular patch group 11 arranged in an equidistant array is laid on the surface of the supersurface layer. The rectangular patch group 11 includes a first rectangular patch P1 etched with a vertical gap, a second rectangular patch P2 etched with two relatively short vertical gaps, and a third rectangular patch P3 etched with a short transverse groove representing a magnetic current, and the second rectangular patch P2 is symmetrical about the third rectangular patch P3.

[0057] Preferably, the number and spacing of the vertical gaps on the first rectangular patch P1 are equal, and the third rectangular patch P3 is located at the center of the rectangular patch group 11. The first rectangular patches P1 exist in rows, and multiple rows of first rectangular patches P1 are symmetrically distributed on the upper and lower sides of the third rectangular patch P3. The second rectangular patch P2 is in the same row as the third rectangular patch P3 and is symmetrically distributed on the left and right sides of the third rectangular patch P3.

[0058] In a specific embodiment, the metasurface layer 1 is a metal copper layer, and the rectangular patch group 11 is composed of 3×3 rectangular patches 111. In this embodiment, to ensure that the metasurface excites the characteristic mode within the expected frequency band, the rectangular patches 111 in the rectangular patch group 11 have the same specifications, and the side length and spacing meet the following empirical formula:

[0059] 3*W p +2*W s =W eq =1.5λ

[0060] Where W p Represents the side length of the rectangular patch, W s Indicates the arrangement spacing, W eq represents the side length of the metasurface layer when it is equivalent to a whole rectangular patch, and λ represents the wavelength of the operating frequency. As a preference, the side length of each rectangular patch 111 in this application is W p =6mm, equal spacing W s =0.4mm arrangement.

[0061] Figure 3In the figure, the rectangular patch P3 is located at the center of the rectangular patch group 11 and integrates a short transverse slot with a width of 0.4mm representing the magnetic current, which is perpendicular to the electric field direction of the half-wavelength electric field mode of the funnel gap 21, thereby selectively exciting the desired mode. Secondly, the first rectangular patches P1 in the first and third rows of the rectangular patch group 11 are vertically etched with 0.4mm gaps at equal intervals, so that the first rectangular patch P1 excites only the surface current in the y-axis direction and suppresses the characteristic mode in other current directions. Since the second rectangular patch P2 will be affected by the coupling interference of the first rectangular patch P1 in the first and third rows, two vertical gaps with a length of 1.5mm and a width of 0.4mm are etched in the center of the two second rectangular patches P2 of the rectangular patch group 11. If the second rectangular patch P2 excites the surface current in the x-axis direction, due to symmetry, the current directions of the two second rectangular patches P2 are opposite, and the mutual cancellation between the two patches can reduce coupling interference.

[0062] Furthermore, to enhance the modal significance (MS) of the characteristic modes and make them more easily excited, this application employs a concave arc at the outer edge of at least one row of first rectangular patches located at the boundary of the metasurface layer for transition cutting. Preferably, a 42mm radius arc is used for transition cutting at the top and bottom of the metasurface layer boundary.

[0063] Figure 4 The MS diagram of the four characteristic modes of the metasurface antenna unit is given. It can be seen from the figure that the four characteristic modes can be excited in the Ku band and have high modal significance.

[0064] Figure 5 It is a schematic diagram of the surface current of the four characteristic modes of the metasurface antenna unit at 12.5GHz. The currents J1, J2, J3 and J4 correspond to the surface currents of the four characteristic modes of characteristic mode 1, characteristic mode 2, characteristic mode 3 and characteristic mode 4 respectively. It can be observed that in J1 and J2, the first rectangular patch P1 and the third rectangular patch P3 only have surface currents in the y-axis direction, and the surface currents of the second rectangular patch P2 in the x-axis direction are opposite and cancel each other out, which is equivalent to the rectangular patch group 11 only having surface currents in the y-axis direction; while in J3 and J4, the rectangular patch group 11 only has surface currents in the y-axis direction; therefore, the four characteristic modes excited only have surface currents in the y-axis direction, which improves the energy confinement capability of the system. This localization effect not only enhances the concentration of the electromagnetic field, but also effectively reduces radiation loss.

[0065] In one embodiment,

[0066] The upper dielectric layer 4 is a Rogers RT3003 dielectric substrate with a thickness of 2.28 mm, which is used to support the metasurface structure.

[0067] In one embodiment,

[0068] SIW is used to couple and excite the characteristic modes of the metasurface. Its structure is as follows: Figure 6 Specifically, a funnel-shaped gap 21 and a short-circuit through-hole group 52 are combined to suppress irrelevant modes, stimulate target modes, and improve impedance matching and energy coupling efficiency.

[0069] In this embodiment, the SIW is composed of the following from top to bottom: a slotted ground layer 2, a SIW waveguide layer 5, and a SIW feed layer 3; wherein,

[0070] The slotted ground layer 2 is a metal copper layer with a funnel-shaped slot 21 etched therein;

[0071] The SIW waveguide layer 5 is a 0.76mm-thick Rogers RT3003 dielectric substrate with a relative dielectric constant of 3, enabling low-loss signal transmission at high frequencies. Metal vias within the SIW waveguide layer 5 connect the slotted ground layer 2 and the SIW feed layer 3. The substrate-integrated waveguide is a novel planarized waveguide structure that achieves the transmission characteristics of a traditional rectangular waveguide by integrating metal vias into a dielectric substrate to form a closed channel. It also offers the low-cost and easy-to-integrate advantages of microstrip circuits, making it suitable for high-frequency signal transmission.

[0072] The SIW feed layer 3 is a metal copper layer loaded with a 50Ω feed line 31 .

[0073] In a specific embodiment, in order to effectively center the energy in the cavity and reduce electromagnetic field leakage, the arrangement and specifications of the array through holes in the SIW waveguide layer need to meet the following requirements:

[0074] 20*r≤λ,4*r≥d

[0075] Where r is the through hole radius, d is the center-to-center distance between adjacent through holes, and λ is the wavelength of the operating frequency.

[0076] In this embodiment, continue to refer to Figure 6 In the figure, the radius r of the SIW array through hole 51 is 0.5 mm, and the hole center distance d is 1.5 mm.

[0077] In this application, due to the discontinuity of the through-hole, the SIW only supports TE mode transmission, thereby reducing the design complexity.

[0078] Furthermore, the short-circuit via 52 in the SIW waveguide layer is used to redistribute the TE electric field mode distribution of the SIW, so that the funnel-shaped slot 21 excites the half-wavelength mode;

[0079] The radii of two of the through holes are the same as the radius of the array through holes, and their positions are symmetrical about the vertical center axis of the array through hole area in the horizontal direction. The horizontal spacing is less than four times the through hole radius r, and the vertical direction is located in the upper center of the array through hole area, ensuring that there is only one standing wave in the upper half of the through hole.

[0080] In this embodiment, the hole center distance in the horizontal direction may be between 0.5 and 2 mm; and the hole center distance in the vertical direction may be between 0.5 and 1 mm after optimization.

[0081] Preferably, the radius of the short-circuit through hole is 0.5 mm, and the hole center distances in the horizontal and vertical directions are 1.5 mm and 0.5 mm respectively.

[0082] Furthermore, the funnel-shaped slot 21 of the short-circuit via hole needs to be located approximately one-tenth of a wavelength away from the top of the array via hole region so that the slot excites a half-wavelength mode.

[0083] In a specific embodiment, the slot length of the funnel-shaped slot 21 is greater than half the working wavelength, and is used to couple the electromagnetic waves transmitted inside the SIW to the free space to achieve effective radiation of energy, thereby coupling and exciting the characteristic mode of the metasurface.

[0084] In some embodiments, the funnel-shaped slot 21 has a length of 17.7 mm, a center width of 1.6 mm, and a width of 3 mm at both ends. Furthermore, chamfers are used to create transitions in the width variation region. In this application, the funnel-shaped slot structure optimizes impedance matching through a gradually expanding design, enhancing the coupling efficiency of energy from the SIW waveguide layer to the external space.

[0085] further, Figure 7 is a schematic diagram of the input impedance Z11 and surface current at Z3 of the metasurface antenna unit, where the input impedance Z11 is Figure 7 The horizontal axis is , Z3 is the electric field resonance mode caused by the metasurface characteristic mode 3. TEmn0 refers to the resonance mode caused by the SIW, where m represents the number of standing waves in the X-axis direction inside the SIW cavity, and n represents the number of standing waves in the Y-axis direction.

[0086] When the SIW is not inserted into the short-circuit via group 52, the cavity excites electric field resonance modes of half TE110, TE110, TE120, half TE310, TE310, TE130, and TE320. When the SIW is inserted into the short-circuit via group 52, the TE310 and TE130 modes are suppressed and a hybrid mode is excited at 15.1 GHz, where the hybrid mode is a superposition of half TE310 and TE320.

[0087] Figure 8This is a schematic diagram of the electric field of the SIW at the half TE110, TE110, TE120, half TE310, mixed TE mode, and TE320 resonance points after the short-circuit through-hole group 52 is inserted. The figure shows that only one standing wave appears at the four resonance points of half TE110, TE110, TE120, and half TE310 in the upper half of the cavity of the short-circuit through-hole group 52 of the SIW, and the antinode of the standing wave is located at the center of the funnel-shaped slot 21, thereby exciting the half-wavelength mode of the funnel-shaped slot 21.

[0088] The resonant modes of the SIW are used to excite the characteristic modes of the metasurface. Figure 4 Modal significance analysis in , and Figure 7 The change in the SIW input impedance Z11 after inserting the short-circuit via group 52 shows that the metasurface antenna unit has a potential operating bandwidth between TE120 and half TE310. Figure 7 The change trend in the input impedance Z11 of the SIW structure after inserting the short-circuit via group 52 and loading the metasurface structure shows that the metasurface antenna unit excites a new resonant mode Z3 at 12.5 GHz. This mode is introduced by the metasurface structure. By comparing the surface current distribution of the metasurface under this mode, it can be confirmed that the resonant mode Z3 is excited by the characteristic mode 3.

[0089] Since only a single characteristic mode is excited, the mutual coupling and interference problems that may be caused by the coexistence of multiple modes are avoided, making the electromagnetic field distribution more stable, thereby improving the radiation purity and directivity of the antenna.

[0090] The return loss S11 and gain curve of the metasurface antenna unit of this application are as follows: Figure 9 The operating bandwidth is 11.8-13.0 GHz, and the in-band gain is 7.0-8.1 dBi. The S11's -15 dB bandwidth is 11.9-12.8 GHz. This antenna unit features wide bandwidth, high gain, low loss, and a low profile.

[0091] Example 2

[0092] In order to enhance beam directivity and reduce sidelobe interference, and to adapt to applications requiring higher gain and greater beam control, multiple metasurface antenna units are arranged in an array. In one embodiment, the antenna array is arranged in a 2*2 pattern, where the top view of the antenna array is as follows: Figure 10 shown.

[0093] To avoid coupling interference, the spacing between the metasurface antenna units in this embodiment is greater than half the working wavelength, otherwise grating lobes will be generated, leading to enhanced side lobes, causing energy to be radiated in undesirable directions, affecting the directivity of the antenna. In this application, the spacing value is preferably 33 mm.

[0094] Furthermore, the bottom view of the antenna array is as follows Figure 11 As shown, in order to synchronously feed the antenna array, the present application designs a power divider structure to achieve one-to-four feeding. Specifically, the array metal through-holes form a first-level T-type SIW power divider 53 and two second-level T-type SIW power dividers 54 located at the ends of the first-level T-type SIW power divider, and the first-level T-type SIW power divider has a 180-degree phase difference compensation to keep the surface currents of the metasurface of the first and second rows of metasurface antenna units in phase, thereby avoiding the radiation blind spot in the center horizontal direction. This design optimizes the radiation performance of the antenna array.

[0095] In order to further optimize the above technical solution, the two-stage T-type SIW power divider 54 of the present application is loaded with a guide through-hole group 541, which is used to guide the propagation direction of the electromagnetic wave and constrain the electromagnetic field distribution, so that each metasurface antenna unit only supports one stable standing wave mode in the horizontal direction, thereby effectively exciting the half-wavelength mode of the funnel-shaped gap 21.

[0096] In addition, the SIW feeding layer 3 of the antenna array is loaded with a 50Ω feeding line 31 with a width of 2.4 mm, which is used for external connection to the SMA port for coplanar waveguide feeding.

[0097] The return loss S11 and gain curves of the metasurface antenna array in this application are as follows: Figure 12 As shown in the figure. Although the electromagnetic coupling effect between adjacent units interferes with the longer-wavelength, low-frequency portion of the bandwidth, resulting in a reduction in bandwidth, the antenna still features wide bandwidth and high gain, with an operating bandwidth of 12.2-13.0 GHz and an in-band gain of 8.2-10.1 dBi, supporting high-definition video streaming and real-time control signal transmission for drones. The S11's -15dB bandwidth is 12.27-12.97 GHz. The antenna also exhibits strong out-of-band suppression, effectively suppressing unnecessary parasitic radiation in non-operating frequency bands and improving the system's spectral purity. This feature reduces interference in high-frequency applications and improves signal stability and reliability.

[0098] The main polarization and cross-polarization patterns of the antenna array at 12.4 GHz and 12.9 GHz are shown in Figure 2. Figure 13 As shown in the figure, the antenna array exhibits strong mainlobe gain and low sidelobe effects in the main radiation direction, providing excellent directivity and ensuring accurate signal coverage of the target area. Furthermore, the cross-polarization level is significantly lower than the main polarization level, further demonstrating the antenna array's high polarization isolation capability. With a total thickness of less than 4mm, the antenna is lightweight and easy to integrate, making it suitable for miniaturized drone platforms.

[0099] Therefore, the antenna array not only has broadband, high gain and excellent directivity, but also has good polarization purity and anti-interference capability, and can provide stable and reliable performance for UAV cluster collaborative communication, high-definition image transmission and precise control.

[0100] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0101] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is intended to be consistent with the principles and novel features disclosed herein.

Claims

1. A Ku-band antenna array for UAV communications, characterized in that: The invention comprises a plurality of metasurface antenna units, wherein the metasurface antenna unit comprises a metasurface layer and a SIW waveguide layer; The surface of the metasurface layer is paved with a group of rectangular patches arranged in an array with equal spacing. The patch group includes a first rectangular patch etched with a vertical slit, a second rectangular patch etched with two relatively short vertical slits, and a third rectangular patch etched with a short horizontal groove, and the second rectangular patch is symmetrical about the third rectangular patch; the third rectangular patch is located at the center of the rectangular patch group, the first rectangular patches exist in a row, and multiple rows of the first rectangular patches are symmetrically distributed on the upper and lower sides of the third rectangular patch. The second rectangular patches are in the same row as the third rectangular patch and are symmetrically distributed on the left and right sides of the third rectangular patch. The rectangular patches in the rectangular patch group have the same specifications, and the side lengths and arrangement spacing satisfy the following relationship: 3*W p +2*W s =W eq =1.5λ Where W p Represents the side length of the rectangular patch, W s Indicates the arrangement spacing, W eq represents the side length of the metasurface layer when it is equivalent to a whole rectangular patch, and λ represents the wavelength of the operating frequency; The SIW waveguide layer is preset with short-circuit vias and array metal vias, which are used to connect the SIW feeding layer and the slotted ground layer to couple and excite the characteristic modes of the metasurface layer.

2. The antenna array according to claim 1, wherein: The first rectangular patch excites a surface current in the y-axis direction, and the second rectangular patch excites a surface current in the x-axis direction.

3. The antenna array according to claim 1, wherein: At least one row of first rectangular patches located at the boundary of the super surface layer is transitionally cut using an inward concave arc at the outer edge.

4. The antenna array according to claim 1, wherein: The arrangement and specifications of the array through holes in the SIW waveguide layer meet the following requirements: 20*r≤λ,4*r≥d Where r is the through hole radius, d is the center-to-center distance between adjacent through holes, and λ is the wavelength of the operating frequency.

5. The antenna array according to claim 1, wherein: The gap in the slotted ground layer is a funnel-shaped gap, and the gap length is greater than half of the working wavelength.

6. The antenna array according to claim 1, wherein: Multiple metasurface antenna units are arranged in an array.

7. The antenna array according to claim 6, characterized in that The array metal through holes form a first-level T-shaped SIW power divider and two second-level T-shaped SIW power dividers located at ends of the first-level T-shaped SIW power divider, and the first-level T-shaped SIW power divider has a 180-degree phase difference compensation.

8. The antenna array according to claim 7, characterized in that The two-stage T-type SIW power divider is loaded with a guide through-hole group for guiding the propagation direction of electromagnetic waves and constraining the electromagnetic field distribution.

Images