Satellite-borne millimeter wave array antenna

Abstract

The utility model provides a satellite-borne millimeter wave array antenna. The satellite-borne millimeter wave dipole antenna comprises an isolation cavity with a bottom surface, a dipole body and a conductor, the conductor is located in the isolation cavity, the bottom end of the conductor is connected with the bottom surface of the isolation cavity, and the dipole body is arranged at the top end of the conductor and connected to the bottom surface of the isolation cavity through the conductor. The array body comprises a pair of array long arms and a pair of array short arms which are orthogonally arranged, the pair of array long arms are symmetrically arranged relative to the axis direction of the conductor, the pair of array short arms are symmetrically arranged relative to the axis direction of the conductor, and the phase difference between the adjacent array long arms and array short arms is 90 degrees. At least one of the oscillator long arm and the oscillator short arm is provided with at least one crack along the radial direction.

Description

Technical Field

[0001] The present disclosure relates to the field of antenna technology, and particularly to a spaceborne millimeter-wave dipole antenna. Background Art

[0002] With the rapid construction of low-earth orbit internet satellite constellations and the demand for massive data transmission, higher requirements are put forward for spaceborne communication phased array antennas. On the one hand, the working frequency band migrates to higher frequency bands (ku and ka bands); on the other hand, the wide-area coverage communication requires that the spaceborne phased array antenna has higher gain, wider beam, wider axial ratio bandwidth and working bandwidth.

[0003] Currently, the conventional types of spaceborne antennas include microstrip antennas, helical antennas, and dipole antennas. Among them, the microstrip antenna has a low profile and is easy to miniaturize, but its conventional bandwidth is narrow, and it faces the risk of delamination failure caused by high and low temperature alternation in the vacuum environment. The helical antenna has a wide bandwidth, high gain, and wide beam, but its profile is high, it is not suitable for large-scale array applications, and it is difficult to process and implement in the millimeter-wave band. The dipole antenna has simple materials and high gain, but generally has a narrow beam width and axial ratio bandwidth. Therefore, it is necessary to design a broadband wide-beam circularly polarized dipole sub-array for spaceborne millimeter-wave phased array antenna applications to solve the defects in the prior art that the antenna cannot achieve wide frequency band, wide beam, high reliability, and easy large-scale array in satellite communication.

[0004] Previously, there was proposed a low-profile wide-angle horn antenna, which expands the beam width of the dipole antenna by loading a horn cavity (refer to Patent Document 1). However, the envelope size of this antenna is too large and the normal gain is too low, so it is not suitable for use as a phased array antenna element in the millimeter-wave band.

[0005] In addition, there was also proposed a miniaturized combined microstrip-symmetrical dipole dual-frequency antenna, which achieved miniaturization and wide frequency (refer to Patent Document 2). However, the structure of this antenna is still based on the microstrip structure and is fixed by air suspension, so it is not suitable for use as a spaceborne antenna.

[0006] In addition, there was also proposed a spaceborne millimeter-wave cross dipole antenna, which realizes circular polarization through the cross dipole form and expands the beam width through the cavity (refer to Patent Document 3). However, the beam radiation of this antenna is not uniform, that is, the gain difference between azimuth angles of 0 degrees and 90 degrees within a pitch angle of 55 degrees is greater than 1 dB, and it cannot solve the problems of non-uniform radiation during wide-angle scanning of the phased array antenna beam and too fast decline of the gain at a certain azimuth angle.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Chinese Patent Publication CN215008584U

[0010] Patent Document 2: Chinese Patent Publication No. CN111048891A

[0011] Patent Document 3: Chinese Patent Publication No. CN213905602U Utility Model Content

[0012] This disclosure is completed to solve the above problems in the prior art, and its purpose is to provide a spaceborne millimeter-wave dipole antenna, which can expand the antenna bandwidth and beam width, make the pattern radiation uniform, and has a small envelope size and is easy to form an array on a large scale.

[0013] According to an exemplary embodiment of the present disclosure, there is provided a spaceborne millimeter-wave dipole antenna, characterized in that it includes an isolation cavity having a bottom surface, a dipole body, and a conductor. The conductor is located in the isolation cavity and its bottom end is connected to the bottom surface of the isolation cavity. The dipole body is provided at the top end of the conductor and is connected to the bottom surface of the isolation cavity via the conductor. The dipole body includes a pair of dipole long arms and a pair of dipole short arms arranged orthogonally. The pair of dipole long arms are symmetrically arranged with respect to the axis direction of the conductor, and the pair of dipole short arms are symmetrically arranged with respect to the axis direction of the conductor. The phase difference between adjacent dipole long arms and dipole short arms is 90 degrees, and at least one of the dipole long arms and the dipole short arms is provided with at least one crack along its radial direction.

[0014] Optionally, in the above spaceborne millimeter-wave dipole antenna, the radial length of the crack is 1 / 8 to 3 / 4 of the radial length of the dipole long arm or the dipole short arm, and the circumferential width of the crack is 0.2 to 0.3 mm.

[0015] Optionally, in the above spaceborne millimeter-wave dipole antenna, a plurality of the cracks are provided on one of the dipole long arms or the dipole short arms.

[0016] Optionally, in the above spaceborne millimeter-wave dipole antenna, on one of the dipole long arms or the dipole short arms, the plurality of cracks are arranged in parallel.

[0017] Optionally, in the above spaceborne millimeter-wave dipole antenna, the dipole long arms and the dipole short arms are split into a plurality of split parts with different radial lengths by the cracks.

[0018] Optionally, in the above spaceborne millimeter-wave dipole antenna, the dipole long arms and the dipole short arms are formed in a fan shape.

[0019] Optionally, in the above spaceborne millimeter-wave dipole antenna, the fan angle of the dipole long arm is the same as the fan angle of the dipole short arm.

[0020] Optionally, in the above-mentioned spaceborne millimeter-wave dipole antenna, the isolation cavity includes an outer cavity and an inner cavity in the shape of a coaxial ring disposed on the bottom surface, and the conductor is located inside the inner cavity.

[0021] Optionally, in the above-mentioned spaceborne millimeter-wave dipole antenna, the height of the outer cavity is greater than the height of the inner cavity.

[0022] Optionally, in the above-mentioned spaceborne millimeter-wave dipole antenna, the conductor includes an outer conductor and an inner conductor disposed coaxially. The outer conductor is hollow inside. The long arm and the short arm of the dipole are disposed at the top of the outer conductor. The inner conductor is disposed inside the outer conductor and is connected to one of the long arms or one of the short arms of the dipole.

[0023] Optionally, in the above-mentioned spaceborne millimeter-wave dipole antenna, a matching slot is provided along the axial direction of the outer conductor from the top of the outer conductor between the long arm and the short arm of the dipole.

[0024] Optionally, in the above-mentioned spaceborne millimeter-wave dipole antenna, the axial length of the matching slot is 0.23 - 0.27λ, and the circumferential width of the matching slot is 0.01 - 0.03λ, where λ represents the wavelength corresponding to the working center frequency.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] (1) The spaceborne millimeter-wave dipole antenna of the present invention can achieve excellent circular polarization characteristics by providing at least one crack along the radial direction of at least one of the long arm and the short arm of the dipole body, that is, by using a split dipole arm to replace the conventional dipole arm, thereby expanding the antenna bandwidth and beam width.

[0027] (2) The spaceborne millimeter-wave dipole antenna of the present invention can make the radiation pattern uniform, has excellent front-to-back ratio performance, improves the anti-interference ability of the surrounding environment, and reduces the coupling between array elements.

[0028] (3) The spaceborne millimeter-wave dipole antenna of the present invention has a simple structure, a small envelope size, is easy to form an array on a large scale, and is very suitable for the millimeter-wave spaceborne phased array antenna elements for satellite communication applications.

[0029] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly, it can be implemented according to the content of the description. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the specific embodiments of this application are specifically given below. Description of the Drawings

[0030] Upon reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0031] Figure 1 A perspective view showing the structure of the spaceborne millimeter-wave dipole antenna related to Embodiment 1 of the present disclosure;

[0032] Figure 2 A top view showing the structure of the spaceborne millimeter-wave dipole antenna related to Embodiment 1 of the present disclosure;

[0033] Figure 3 A perspective view showing an example of the structure of the conductor in the spaceborne millimeter-wave dipole antenna related to Embodiment 1 of the present disclosure;

[0034] Figure 4 A schematic diagram showing the structure of the dipole body in the spaceborne millimeter-wave dipole antenna related to Variant 1 of Embodiment 1 of the present disclosure;

[0035] Figure 5 A schematic diagram showing the structure of the dipole body in the spaceborne millimeter-wave dipole antenna related to Variant 2 of Embodiment 1 of the present disclosure;

[0036] Figure 6 A perspective view showing the structure of the spaceborne millimeter-wave dipole antenna related to Embodiment 2 of the present disclosure;

[0037] Figure 7 A top view showing the structure of the spaceborne millimeter-wave dipole antenna related to Embodiment 2 of the present disclosure;

[0038] Figure 8 A simulation standing wave curve graph showing an example of the spaceborne millimeter-wave dipole antenna of the present disclosure;

[0039] Figure 9 A simulation axial ratio curve graph showing an example of the spaceborne millimeter-wave dipole antenna of the present disclosure;

[0040] Figure 10 A simulation gain curve graph showing an example of the spaceborne millimeter-wave dipole antenna of the present disclosure. Detailed Embodiments

[0041] Specific embodiments of the present disclosure will be described below. It should be noted that in the specific description of these embodiments, for the sake of brevity, this specification may not describe all features of the actual embodiments in detail. It should be understood that in the actual implementation of any embodiment, just as in the process of any engineering project or design project, in order to achieve the specific goals of the developer and to meet system-related or business-related constraints, various specific decisions are often made, and these may vary from one embodiment to another. In addition, it should also be understood that although the efforts made in such a development process may be complex and time-consuming, for those of ordinary skill in the art related to the content of the present disclosure, some design, manufacturing, or production changes based on the technical content disclosed in the present disclosure are only conventional technical means and should not be construed as insufficient content of the present disclosure.

[0042] Unless otherwise defined, technical terms or scientific terms used in the claims and the specification shall have the ordinary meanings understood by those of ordinary skill in the technical field to which the present disclosure pertains. The terms "first", "second", and similar terms used in the specification and claims of the present patent application do not denote any order, quantity, or importance, but are merely used to distinguish different components. The terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. The terms "comprising" or "including" and the like mean that the elements or items appearing before "comprising" or "including" cover the elements or items listed after "comprising" or "including" and their equivalent elements, and do not exclude other elements or items. The terms "connected" or "coupled" and the like are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0043] In the present disclosure, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may include direct contact between the first and second features, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes the first feature being directly above and diagonally above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below", and "beneath" the second feature includes the first feature being directly below and diagonally below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0044] In the present disclosure, unless otherwise specified, all the embodiments and preferred embodiments mentioned herein can be combined with each other to form a new technical solution. In the present disclosure, unless otherwise specified, all the technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0045] The spaceborne millimeter-wave dipole antenna of the present disclosure includes an isolation cavity with a bottom surface, a dipole body, and a conductor. The conductor is located inside the isolation cavity and its bottom end is connected to the bottom surface of the isolation cavity. The dipole body is arranged at the top end of the conductor and is connected to the bottom surface of the isolation cavity via the conductor. The dipole body includes a pair of dipole long arms and a pair of dipole short arms arranged orthogonally. The pair of dipole long arms are symmetrically arranged with respect to the axis direction of the conductor, and the pair of dipole short arms are symmetrically arranged with respect to the axis direction of the conductor. The phase difference between adjacent dipole long arms and dipole short arms is 90 degrees. At least one of the dipole long arms and the dipole short arms is provided with at least one crack along its radial direction.

[0046] According to the spaceborne millimeter-wave dipole antenna involved in the present disclosure, the antenna bandwidth and beam width can be expanded, the radiation of the radiation pattern can be made uniform, and the envelope size is small, which is easy to form an array on a large scale.

[0047] The embodiments of the present disclosure will be described below with reference to the drawings. It should be understood that the embodiments described herein are only used to illustrate and explain the present disclosure and are not used to limit the present disclosure.

[0048] 《Embodiment 1》

[0049] Hereinafter, with reference to Figures 1 to 2 , the structure of the spaceborne millimeter-wave dipole antenna 1 involved in Embodiment 1 of the present disclosure will be described. Figure 1 and Figure 2 are respectively a perspective view and a top view showing the structure of the spaceborne millimeter-wave dipole antenna 1.

[0050] As Figure 1 shown, the spaceborne millimeter-wave dipole antenna 1 includes an isolation cavity 11, a dipole body 12, and a conductor 13. The isolation cavity 11 has a bottom surface 111, preferably a circular ring metal cavity. When a circular ring metal cavity is used, the coupling degree between antennas can be improved, the beam width can be expanded, and the radiation of the radiation pattern can be made more uniform. When a circular ring metal cavity is used, the radius of the isolation cavity 11 can be 0.25 - 0.28λ. Herein, λ represents the wavelength corresponding to the working center frequency of the antenna. Of course, the present disclosure is not limited thereto, and the isolation cavity 11 can also be a cavity of other shapes such as a square cavity. The height of the isolation cavity 11 is preferably less than the height of the dipole body 12. The difference between the height of the dipole body 12 and the height of the isolation cavity 11 can be 1 / 4 - 1 / 8λ.

[0051] The conductor 13 is located within the isolation cavity 11, and its bottom end is connected to the bottom surface 111 of the isolation cavity 11.

[0052] The dipole body 12 is disposed at the top end of the conductor 13 and is connected to the bottom surface 111 of the isolation cavity 11 via the conductor 13. As Figure 2 shown, the dipole body 12 includes a pair of dipole long arms 121 and a pair of dipole short arms 122 disposed orthogonally. The dipole long arms 121 and the dipole short arms 122 can be formed into a fan shape. Of course, the present disclosure is not limited thereto, and other shapes such as a square shape can also be formed. In the case of a fan shape, it is preferably that the fan angles of the dipole long arms 121 and the dipole short arms 122 are the same, that is, the center of the fan becomes the center of the dipole body 12.

[0053] A pair of dipole long arms 121 are symmetrically disposed with respect to the axial direction of the conductor 13, and a pair of dipole short arms 122 are symmetrically disposed with respect to the axial direction of the conductor 13. The phase difference between adjacent dipole long arms 121 and dipole short arms 122 is 90 degrees.

[0054] Excellent circular polarization characteristics can be achieved by using dipole long arms 121 and dipole short arms 122 with different lengths. A pair of dipole long arms 121 form a pair of oscillators, and a pair of dipole short arms 122 form a pair of oscillators. When the oscillators themselves have different electrical lengths, the currents on them will exhibit different phases. When the electrical length of a symmetric oscillator approaches λ / 2, its input impedance is approximately a pure resistance. When an excitation voltage is applied, the initial phase of the current at the feeding point can be considered as 0°. When the electrical length of a symmetric oscillator is less than λ / 2, its input impedance will exhibit capacitive characteristics, and the initial phase of the current at the feeding point is ahead of 0°. When the electrical length of a symmetric oscillator is greater than λ / 2, its input impedance will exhibit inductive characteristics, and the initial phase of the current at the feeding point lags behind 0°. Therefore, when two pairs of orthogonally placed oscillators are fed simultaneously, by appropriately adjusting the lengths of the two pairs of oscillators, the phase difference of the currents on them can be exactly 90°. Moreover, by changing the different placement positions of the two pairs of oscillators relative to the feeding point, left-handed or right-handed circular polarization radiation can be generated, and its polarization characteristics are determined by the component that leads among the two current components turning to the component that lags, that is, from the short arm to the long arm.

[0055] In addition, in the present Embodiment 1, as Figure 2 shown, a crack 120 is provided along the radial direction of a pair of dipole long arms 121 and a pair of dipole short arms 122. In some embodiments of the present disclosure, the radial length of the crack 120 can be 1 / 8 to 3 / 4 of the radial length of the dipole long arm 121 or the dipole short arm 122, and the circumferential width of the crack 120 can be 0.2 to 0.3 mm. By providing a crack in the dipole arm and adjusting the size of the crack 120, the path of the current can be changed, thereby expanding the antenna bandwidth and beam width.

[0056] The dipole long arm 121 can be split into two split parts 1211 and 1212 with different radial lengths through the slit 120, and the dipole short arm 122 can be split into two split parts 1221 and 1222 with different radial lengths through the slit 120. By splitting the dipole long arm or the dipole short arm into split parts with different radial lengths, more excellent circular polarization characteristics can be achieved.

[0057] Figure 3 FIG. shows an example of the structure of the conductor 13 in the spaceborne millimeter-wave dipole antenna 1. As Figure 3 shown, the conductor 13 may include an outer conductor 131 and an inner conductor 132 arranged coaxially. The outer conductor 131 has a hollow structure inside, and the dipole long arm 121 and the dipole short arm 122 are provided at the top of the outer conductor 131. The inner conductor 132 is arranged inside the outer conductor 131 and is connected to one dipole long arm 121 by, for example, welding to generate left-handed circular polarization radiation. Of course, the present disclosure is not limited to this, and the inner conductor 132 may also be connected to one dipole short arm 122 to generate right-handed circular polarization radiation.

[0058] In addition, as Figure 3 shown, between the dipole long arm 121 and the dipole short arm 122, two matching slots 130 are provided along the axial direction from the top of the outer conductor 131. In order to maintain the symmetry of the oscillator structure, both arms of the slotted line are connected to the outer conductor 131. The slotted section can be understood as a short circuit line. At this time, the input impedance is infinite, and no current flows through the outer conductor 131, achieving the purpose of balanced feeding. By adjusting the size of the matching slot 130, impedance transformation can be achieved, so that the antenna can operate in a relatively wide frequency band. In some embodiments of the present disclosure, the axial length of the matching slot 130 may be 0.23 - 0.27λ, preferably λ / 4. The circumferential width of the matching slot may be 0.01 - 0.03λ.

[0059] In Figure 2 the example, the dipole long arm 121 and the dipole short arm 122 are split into split parts with different radial lengths through the slit 120, but the present disclosure is not limited to this. For example, in Variant 1 of Embodiment 1 of the present disclosure, as Figure 4 shown, the dipole long arm 121 is split into two split parts 1211 and 1212 with the same radial length through the slit 120.

[0060] In addition, in Figure 2In the example, a pair of dipole long arms 121 and a pair of dipole short arms 122 are each provided with a crack 120 along their radial directions. However, the present disclosure is not limited to this. A crack 120 may be provided only on one of the pair of dipole long arms 121 and the pair of dipole short arms 122, or multiple cracks may be provided on one dipole long arm or dipole short arm. In addition, on one dipole long arm or dipole short arm, the multiple cracks may be configured in parallel. At this time, the dipole long arm or dipole short arm is split into multiple split portions by the multiple cracks.

[0061] For example, in Variant Example 2 of Embodiment 1 of the present disclosure, as Figure 5 shown, three cracks 1201, 1202, and 1203 are provided on one dipole short arm 122 and are configured in parallel. By providing multiple cracks on one dipole arm, the path of the current can be further changed, thereby further expanding the antenna bandwidth and beam width.

[0062] For the spaceborne millimeter-wave dipole antenna with the above structure, by providing at least one crack along the radial direction on at least one of the dipole long arm and the dipole short arm of the dipole body, that is, using a split dipole arm to replace the conventional dipole arm, excellent circular polarization characteristics can be achieved, and the antenna bandwidth and beam width can be expanded.

[0063] In addition, for the spaceborne millimeter-wave dipole antenna with the above structure, the radiation pattern can be made uniform, it has excellent front-to-back ratio performance, improves the anti-interference ability of the surrounding environment, and reduces the coupling between array elements.

[0064] In addition, for the spaceborne millimeter-wave dipole antenna with the above structure, it has a simple structure, a small envelope size, is easy to be arrayed in scale, and is very suitable for the millimeter-wave spaceborne phased array antenna elements for satellite communication applications.

[0065] 《Embodiment 2》

[0066] In the above Embodiment 1, an example in which the isolation cavity 11 is a single-layer circular ring cavity is shown. However, in Embodiment 2, the isolation cavity 11 is set as a double-layer circular ring cavity. Figure 6 and Figure 7 are a perspective view and a top view showing the spaceborne millimeter-wave dipole antenna according to Embodiment 2 of the present disclosure.

[0067] As Figure 6 and Figure 7As shown in the figure, the isolation cavity 11 includes an outer cavity 112 and an inner cavity 113 both having a circular ring shape and coaxially arranged on the bottom surface 111. The radius of the outer cavity 112 can be 0.25 to 0.28 wavelengths, and the difference between the radius of the outer cavity 112 and the radius of the inner cavity 113 can be λ / 10 to λ / 6. At this time, the conductor 13 is located inside the inner cavity 113. The height difference between the dipole body 12 and the outer cavity 112 can be λ / 4 to λ / 8.

[0068] As Figure 6 shown in the figure, the height of the outer cavity 112 is preferably greater than the height of the inner cavity 113. The height difference between the outer cavity 112 and the inner cavity 113 can be λ / 10 to λ / 6.

[0069] For the spaceborne millimeter-wave dipole antenna with the above structure, by setting the isolation cavity as a double-layer circular ring cavity, beam broadening, uniform radiation can be achieved, and it has excellent front-to-back ratio performance, can improve the anti-interference ability of the surrounding environment, and reduce the coupling between array elements.

[0070] 《Simulation Example》

[0071] To more intuitively demonstrate the advantages of the spaceborne millimeter-wave dipole antenna of the present invention, taking the spaceborne millimeter-wave dipole antenna with left-handed circular polarization as an example, its performance was simulated. It is assumed that the spaceborne millimeter-wave dipole antenna operates in the frequency band of 18 to 21 GHz, the radius of the outer cavity is about 0.28λ, the height is higher than the inner cavity by about λ / 8, the radius is greater than the inner cavity by about λ / 8 wavelengths, and the axial length of the matching slot is λ / 4.

[0072] Figure 8 To show the simulated standing wave curve of the spaceborne millimeter-wave dipole antenna. As can be seen from the figure, the standing wave is less than 1.5 within 18 to 21 GHz, demonstrating its wideband characteristic.

[0073] Figure 9 To show the simulated axial ratio curve of the spaceborne millimeter-wave dipole antenna. In the figure, Theta represents the elevation angle and Phi represents the azimuth angle. As can be seen from the figure, at 19 GHz, the beam width is greater than 85 degrees, and the axial ratio is less than 2 dB within the range of ±70°, demonstrating its wide beam and circular polarization characteristics.

[0074] Figure 10 To show the simulated gain curve of the spaceborne millimeter-wave dipole antenna. As can be seen from the figure, the normal gain at 19 GHz is greater than 7.3 dB, the front-to-back ratio is greater than 25 dB, and the gain at azimuth angles of 0 degrees and 90 degrees is less than 0.3 dB within the elevation angle of 70 degrees, demonstrating its high gain, uniform radiation, and excellent front-to-back ratio characteristics.

[0075] It should be understood that the above description is illustrative rather than restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. In addition, many modifications can be made to adapt a particular situation or material to the teachings of various embodiments of the present disclosure without departing from the scope of the present disclosure. Although the dimensions and types of the materials described herein are used to define the parameters of various embodiments of the present disclosure, the various embodiments are not meant to be restrictive, but rather exemplary embodiments. Many other embodiments will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the various embodiments of the present disclosure should be determined with reference to the appended claims and the full scope of the equivalents claimed by these claims.

Claims

1. A satellite-borne millimeter wave array antenna, characterized in that: It includes an isolation cavity with a bottom surface, an array body and a conductor, The conductor is located in the isolation cavity, and the bottom end is connected to the bottom surface of the isolation cavity. The array body is disposed on the top of the conductor and connected to the bottom surface of the isolation cavity via the conductor. The array body comprises a pair of array long arms and a pair of array short arms arranged orthogonally, wherein the pair of array long arms are symmetrically arranged relative to the axial direction of the conductor, and the pair of array short arms are symmetrically arranged relative to the axial direction of the conductor, and the phase difference between adjacent array long arms and array short arms is 90 degrees. At least one of the array long arm and the array short arm is provided with at least one crack along its radial direction.

2. The satellite-borne millimeter wave array antenna according to claim 1, characterized in that: The radial length of the crack is 1 / 8 to 3 / 4 of the radial length of the long arm of the array or the short arm of the array, and the circumferential width of the crack is 0.2 to 0.3 mm.

3. The satellite-borne millimeter wave array antenna according to claim 1 or 2, characterized in that: A plurality of the slits are arranged on one of the array long arms or the array short arms.

4. The satellite-borne millimeter wave array antenna according to claim 3, characterized in that: On one of the array long arms or the array short arms, a plurality of the slits are arranged in parallel.

5. The satellite-borne millimeter wave array antenna according to claim 1 or 2, characterized in that: The array long arm and the array short arm are split into a plurality of split parts with different radial lengths through the crack.

6. The satellite-borne millimeter wave array antenna according to claim 1 or 2, characterized in that: The array long arm and the array short arm are formed in a fan shape.

7. The satellite-borne millimeter wave array antenna according to claim 6, characterized in that: The fan angle of the long arm of the array is the same as the fan angle of the short arm of the array.

8. The satellite-borne millimeter wave array antenna according to claim 1 or 2, characterized in that: The isolation cavity comprises an outer cavity and an inner cavity in a circular ring shape coaxially arranged on the bottom surface, and the conductor is located in the inner cavity.

9. The satellite-borne millimeter wave array antenna according to claim 8, characterized in that: The height of the outer cavity is greater than the height of the inner cavity.

10. The satellite-borne millimeter wave array antenna according to claim 1 or 2, characterized in that: The conductor includes an outer conductor and an inner conductor in a coaxial arrangement, The outer conductor is hollow inside. The array long arm and the array short arm are arranged at the top of the outer conductor. The inner conductor is arranged in the outer conductor and connected to one of the array long arms or one of the array short arms.

11. The satellite-borne millimeter wave array antenna according to claim 10, characterized in that: A matching groove is arranged between the array long arm and the array short arm from the top end of the outer conductor along the axial direction thereof.

12. The satellite-borne millimeter wave array antenna according to claim 11, characterized in that: The axial length of the matching groove is 0.23-0.27λ, and the circumferential width of the matching groove is 0.01-0.03λ, where λ represents the wavelength corresponding to the working center frequency.

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