A microstrip antenna unit and a spaceborne phased array antenna

Abstract

The present disclosure relates to the technical field of antennas, in particular to a microstrip antenna unit and a spaceborne phased array antenna. The microstrip antenna unit is applied to the spaceborne phased array antenna. The microstrip antenna unit comprises a ground plate, a dielectric layer arranged on the ground plate, and a radiation patch arranged above the dielectric layer. The radiation patch is circular in whole, concentrically provided with a fan ring-shaped through slot, and at least provided with two open slots at the edge. The radiation patch is used to form a circularly polarized wave through feeding. One or more through holes are arranged at the opening of the fan ring-shaped through slot of the radiation patch, forming a plurality of current paths from the feeding position of the radiation patch to the edge of the radiation patch. The present disclosure can simultaneously realize wide beam, uniform radiation, low profile, high reliability, easy scale array, strong engineering implementation, and has wide application value.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of antennas, in particular to a microstrip antenna unit and a satellite-borne phased array antenna. BACKGROUND

[0002] Due to the circular polarization radiation characteristics, which can effectively overcome the Faraday effect, the circular polarization radiation characteristics are widely used in satellite-borne phased array antennas. With the rapid development of Internet satellite constellations and the demand for massive data transmission, higher requirements are put forward for satellite-borne communication phased array antennas, in which wide coverage communication requires satellite-borne phased array antennas to have higher gain, more uniform radiation, and wider beams, especially the 3dB axial ratio beam width of circular polarization. However, it is more difficult to simultaneously realize wide beam, uniform radiation, high reliability, low profile, and large-scale array of antennas in satellite communication. SUMMARY

[0003] To overcome the problems in the related art, an exemplary embodiment of the present disclosure provides a microstrip antenna unit applied to a satellite-borne phased array antenna, wherein the microstrip antenna unit comprises: a ground plate; a dielectric layer arranged on the ground plate; a radiation patch arranged above the dielectric layer, which is circular in shape as a whole, concentrically provided with a fan ring-shaped through slot, and at least provided with two open slots at the edge, the radiation patch being used to form circularly polarized waves through feeding; wherein the radiation patch is provided with one or more through holes at the opening of the fan ring-shaped through slot, forming a plurality of current paths from the feeding position of the radiation patch to the edge of the radiation patch.

[0004] In some embodiments, the dielectric layer is rectangular, the center of the radiation patch is located at the center of the dielectric layer, and a first through hole is arranged at the center position of the dielectric layer for feeding the center of the radiation patch.

[0005] In some embodiments, the microstrip antenna unit further comprises: four parasitic folded metal patches arranged at the four corners of the upper surface of the dielectric layer, respectively, in an L shape; four second through holes are arranged at the L-shaped corners of the parasitic folded metal patches at the four corners of the dielectric layer, the four second through holes being connected to the ground plate, and the parasitic folded metal patches being in conduction with the ground plate through the second through holes.

[0006] In some embodiments, the radiation patch is provided with two open slots, the shape of the open slots is rectangular, the length of the rectangle is 1.9-2.1mm, and the width of the rectangle is 1.4-1.6mm.

[0007] In some embodiments, the notch of the fan ring-shaped through slot is directed towards one of the open slots and away from the other open slot.

[0008] In some embodiments, the fan-shaped slots are uniformly provided with at least three through holes at the notches.

[0009] In some embodiments, the shape of the through holes is any one of a fan shape, a square shape, a circular shape, a triangular shape, or a fan-shaped slot.

[0010] In some embodiments, the shape of the through holes is a fan shape, and the fan angle is 9-13 degrees.

[0011] In some embodiments, the inner circle radius of the fan-shaped slot is 2.6 mm, the slot width of the fan-shaped slot is 0.8 mm, the arc length angle of the fan-shaped slot is 269 degrees, and the circular radius of the radiation patch is 4.7 mm.

[0012] In a second aspect, the disclosure also provides a spaceborne phased array antenna, wherein the spaceborne phased array antenna comprises a plurality of microstrip antenna units as described in the first aspect, and the plurality of microstrip antenna units are capable of cooperative radiation.

[0013] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and are not limiting to the disclosure.

[0014] The disclosure provides a microstrip antenna unit and a spaceborne phased array antenna, which solves the defects that the existing spaceborne phased array antenna unit is difficult to simultaneously realize wide beam, uniform radiation, low profile, high reliability, and easy scale array. The super surface design of the microstrip antenna breaks through the limitation of the narrow 3dB beam width of the conventional microstrip antenna, and finally realizes the low profile, wide beam, and uniform and symmetrical circularly polarized radiation characteristics of the single-layer microstrip under the combination of the symmetrical structure design. Meanwhile, the present application scheme is a center feeding mode, the feeding port is regular and uniform, easy to scale array, and has strong engineering implementation and wide application value. The antenna is a single-layer microstrip structure, which can effectively avoid the risk of delamination of the antenna under the severe cold-heat alternation in the harsh space environment, effectively improve the reliability, and has extremely low profile and weight, which can save valuable satellite platform resources. BRIEF DESCRIPTION OF DRAWINGS

[0015] The disclosure can be better understood by describing the exemplary embodiments of the disclosure in conjunction with the accompanying drawings, in which:

[0016] Figure 1 is a schematic diagram of a radiation patch according to an exemplary embodiment of the disclosure;

[0017] Figure 2 is a gain direction and axial ratio pattern diagram without fan-shaped structure through holes;

[0018] Figure 3 is a gain direction and axial ratio pattern diagram with fan-shaped structure through holes;

[0019] Figure 4 is a reflection coefficient - frequency band chart shown in accordance with a disclosed exemplary embodiment;

[0020] Figure 5 is an 8 GHz E-plane gain pattern shown in accordance with a disclosed exemplary embodiment;

[0021] Figure 6 is an 8 GHz E-plane circular polarization axial ratio pattern shown in accordance with a disclosed exemplary embodiment. DETAILED DESCRIPTION

[0022] In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a thorough understanding of the inventive concepts. However, it will be apparent to one skilled in the art that embodiments of the application can be practiced without these specific details. In other instances, well-known methods, procedures, components, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein and the claims that follow is not intended to be limiting of the scope of the application and must be read in the context of the entire specification including the claims. The use of numbering and labels such as "first", "second", and "third" or "a", "an", and "the" are used for convenience only and do not require or imply that the applications are limited to any particular number of steps or components. The use of "one" or "the" are intended to mean that there is at least one of the items being referred to. The use of "includes" or "including" means "comprising" or "including" and not by way of limitation. The use of "connected", "coupled", or similar connective language is not limited to mechanical or physical connections, but can include the functionality of being electronically connected, electrically connected, or communicatively connected.

[0024] In the face of wide coverage communication needs, the spaceborne phased array antenna has higher gain, more uniform radiation and wider beam, especially the circularly polarized 3dB axial ratio beam width. Currently, the common types of spaceborne phased array circularly polarized antenna elements are microstrip antenna, array antenna and waveguide antenna. Among them, the microstrip antenna has low profile and is easy to scale array, but the 3dB axial ratio beam width of the conventional single-layer microstrip antenna is narrow, and the radiation pattern symmetry is poor, while the multi-layer microstrip antenna faces the risk of delamination failure caused by high-temperature alternation in vacuum environment. The array antenna has simple material and high gain, but the beam width is generally narrow, and the wide-angle scanning capability is limited after arraying, and the gain decreases too fast at large angle scanning. The waveguide antenna has high gain and good integration, but its all-metal structure is heavy and has large envelope size, which is difficult to meet the requirements of low profile and light weight of satellite platform.

[0025] Currently, the antenna elements easy to scale array mainly include array antenna and microstrip antenna. In some related technologies, the array antenna has excellent wideband circularly polarized performance, but its profile is usually high, and the structure often needs additional mechanical support design, which cannot meet the strong vibration environment of spaceborne. In some other related technologies, the microstrip antenna is used, but the 3dB axial ratio beam width of the microstrip antenna is usually narrow, and in order to expand the beam, the air loading method is often used, and similarly, its structure is not suitable for spaceborne environment. In some other related technologies, a single-layer microstrip antenna is used to expand the beam through the design of a super surface, but the gain pattern radiation is not uniform enough, and the difference between the 0 and 90 degree azimuth gain within 60 degrees is usually greater than 1dB, and the wide-angle uniform coverage performance needs to be further improved after arraying.

[0026] To overcome the problems in the related art, the exemplary embodiments of the present disclosure provide a microstrip antenna element applied to a spaceborne phased array antenna, wherein the microstrip antenna element can include a ground plane, a dielectric layer 200 and a radiation patch 100. The radiation patch 100 can be arranged on the uppermost layer, the dielectric layer 200 is arranged in the middle, and the ground plane is arranged on the bottom layer and connected with an SMA (SubMiniature version A) connector.

[0027] The ground plane, which is usually a metal layer, can be copper or the like, and can cover the entire dielectric layer 200. The ground plane can adopt a periodic structure according to design requirements, such as arraying, slotting, etc. The ground plane can form a standing wave with the radiation patch 100 to produce electromagnetic wave radiation. And by adjusting the structure and size of the ground plane, the input impedance of the antenna can be optimized, and the reflection loss can be reduced. And the ground plane as the base of the microstrip antenna element can make the overall structure stable.

[0028] The medium layer 200 can be arranged on the floor. The medium layer 200 can be arranged between the radiation patch 100 and the floor. The material of the medium layer 200 can be selected from materials with low loss, stable dielectric constant, good thermal stability and mechanical processability, such as PTFE (Polytetrafluoroethylene) substrate and the like. Such materials have extremely low dielectric loss and stable dielectric constant, and are suitable for high frequency use. The thickness of the medium layer 200 can be much smaller than a wavelength, and can be 1 / 10-1 / 20 of a wavelength. The thickness of the medium layer 200 can be appropriately increased to facilitate bandwidth expansion. The medium layer 200 controls the propagation of electromagnetic waves between the patch and the floor through the dielectric constant, and can form a radiation field.

[0029] The radiation patch 100, as shown in Figure 1 The radiation patch 100 can be arranged above the medium layer 200, and can have a circular shape. The radiation patch 100 can be concentrically provided with a fan-shaped slot 110, and at least two open slots 130 can be arranged at the edge of the radiation patch 100. The radiation patch 100 can be used to form a circularly polarized wave through feeding. The radiation patch 100 has a circular shape and has axial symmetry, which is easy to excite orthogonal modes. The radiation patch 100 can be provided with a hollow, which can have a fan-shaped slot 110. The fan-shaped slot 110 and the circular shape of the radiation patch 100 can be concentrically arranged. The fan-shaped slot 110 can divide the radiation patch 100 into multiple current paths, force the current to flow in different directions, generate more orthogonal resonant modes, and expand the bandwidth of the antenna. The edge of the radiation patch 100 is provided with an open slot 130, and the number of the open slot 130 is at least two, which can be two, four or more. The positions of the open slots 130 can be symmetrically distributed, and can be 180 degrees apart or 90 degrees apart, which can ensure the symmetry of the orthogonal modes. The open slot 130 can have a rectangular shape, or a triangular shape, a trapezoidal shape, a fan shape, etc. The depth of the open slot 130 can be designed in cooperation with the fan-shaped slot 110 to avoid introducing additional loss. The open slot 130 can introduce additional reactance compensation to adjust the phase difference between the two orthogonal modes to be close to 90 degrees, which can improve impedance matching and reduce reflection loss. The radiation patch 100 can be fed by a microstrip line or a coaxial probe to form a circularly polarized wave.

[0030] The radiation patch 100 is concentrically provided with the fan ring barrel groove 110. While forming a reliable circularly polarized wave, the structure also has non-central symmetry, so that the current distribution is uneven, and the gain pattern of the circularly polarized wave is also uneven. In the embodiment of the present disclosure, one or more through holes 120 can be arranged at the opening of the fan ring barrel groove 110 of the radiation patch 100, forming multiple current paths from the feeding position of the radiation patch 100 to the edge of the radiation patch 100. When the size of the opening of the fan ring barrel groove 110 is constant, the number of through holes 120 can be increased according to actual conditions. The more the number of through holes 120, the more uniform the current passing through the radiation patch 100. The shape of the through hole 120 can also match the opening of the fan ring barrel groove 110, which can be fan-shaped, triangular, rectangular, etc. The distribution of the through hole 120 can be uniformly arranged at the opening of the fan ring barrel groove 110, or it can be unevenly arranged. The through holes 120 can be relatively close or relatively loose. The width of the through hole 120 can also be adjusted according to the distribution of the current. The through hole 120 can also be arranged in two layers or multiple layers in the radial direction of the circle, and each layer can be arranged side by side or staggered, so as to realize more current paths in the space and achieve the purpose of uniform current. The radiation patch 100 is concentrically provided with the fan ring barrel groove 110, which causes the structure to have non-central symmetry. The embodiment of the present disclosure can guide the current to the maximum extent by arranging one or more through holes 120 at the opening of the fan ring barrel groove 110 of the radiation patch 100, so as to make the current distribution more uniform, make the shape of the antenna more symmetrical, and make the gain pattern more uniform and symmetrical. Moreover, the multiple current paths can make the amplitudes of the orthogonal electric field components more equal and the phase difference more close to 90 degrees, thereby reducing the axial ratio. The arrangement of the through hole 120 in the radiation patch 100 significantly improves the circular polarization performance and bandwidth of the microstrip antenna unit by reconstructing the current path. The core advantage lies in that the multiple current paths work together to realize the axial ratio, impedance matching and gain optimization that the traditional single-path patch cannot achieve. Figure 2 The gain patterns and axial ratio patterns of the H plane and the E plane before adding multiple through holes are as follows: Figure 3 The gain patterns and axial ratio patterns of the H plane and the E plane after adding multiple through holes are as follows: Figure 2 Figure 3 As shown in the figure, after adding multiple through holes, the current is forced to form a multi-path symmetrical flow on the patch surface, and the gain pattern and the axial ratio pattern are more symmetrical. In particular, the gain pattern, the simulation result within the pitch angle of plus or minus 60 degrees, the E plane and the H plane gain difference is less than 0.2 dB, and the directional pattern radiation is more uniform.

[0031] ​In the embodiments of the present disclosure, the symmetry of the antenna is improved, so that the antenna has very good pattern symmetry and uniform radiation, and the feed ports are arranged uniformly and regularly, which is beneficial to scale array. Through the design of the metasurface of the microstrip antenna, the limitation of the narrow 3dB beam width of the conventional microstrip antenna is broken, and the low profile, wide beam, and uniform and symmetrical circularly polarized radiation characteristics of the single-layer microstrip are finally realized by combining the symmetrical structure design. Meanwhile, the present application is a center feeding method, the feed ports are regularly and uniformly arranged, which is easy to scale array, has strong engineering implementation, and has wide application value. The antenna is a single-layer microstrip structure, which can effectively avoid the risk of delamination of the antenna in the severe space environment of cold and hot alternation, effectively improve the reliability, and has extremely low profile and weight, which can save valuable satellite platform resources.

[0032] In some embodiments, the medium layer 200 can be rectangular, the center of the radiation patch 100 is located at the center of the medium layer 200, and a first through hole is arranged at the center position of the medium layer 200 for feeding the center of the radiation patch 100. The center of the radiation patch 100 coincides with the first through hole at the center of the rectangular medium layer 200, which can form an axisymmetric structure. The first through hole penetrates the center of the medium layer 200, connects the radiation patch 100 and the ground plate, and forms a single-point coaxial feeding. The feeding point is arranged at the center, and center feeding can be performed. The orthogonal components of the center feeding have equal amplitudes and a phase difference close to 90 degrees, which can form a circularly polarized wave. And the radio frequency signal can be directly coupled to the center position of the radiation patch through a coaxial probe or a metalized hole. The medium layer 200 can be rectangular, and the feed ports are arranged uniformly and regularly, which is easy to scale array. In the embodiments of the present disclosure, the combination of the rectangular medium layer and the center feeding through hole effectively balances the integration convenience and radiation performance of the microstrip antenna through geometric symmetry design. And by using the axisymmetric characteristics of the center feeding, through the cooperative optimization of the fan ring-shaped through slot 110 and the open slot 130, wide-angle uniform radiation and high circular polarization purity are realized, and the feed ports are arranged uniformly and regularly, which is easy to scale array.

[0033] In some embodiments, the microstrip antenna unit can further include: four parasitic folded metal patches, which can be respectively arranged at the four corners of the upper surface of the dielectric layer 200, in the shape of L; the four corners of the dielectric layer 200 can be provided with four second through holes corresponding to the L-shaped corners of the parasitic folded metal patches, the four second through holes can be connected to the ground plane, and the parasitic folded metal patches can be connected to the ground plane through the second through holes. The four corners of the dielectric layer 200 are provided with L-shaped parasitic folded metal patches 140, and the bending part of the L-shaped structure can be connected to the ground plane and conductive to the ground plane, which can guide the current to flow along the L-shaped path and change the current distribution on the surface of the antenna. In addition, the two sides of the L-shaped structure can be the same length, which can form a symmetrical current path, so that the current distribution on the surface of the patch is more uniform, and the asymmetric edge field leakage can be suppressed. The four corners of the dielectric layer 200 can be provided with four second through holes corresponding to the parasitic folded metal patches 140, and the four second through holes can be connected to the ground plane. The length of the parasitic folded metal patch 140 can be 1 / 8-1 / 4 wavelength, when the length of the patch is close to 1 / 4 wavelength, the impedance bandwidth can be expanded, and when the length of the patch is close to 1 / 8 wavelength, the impedance matching near the feed point can be optimized, while reducing the interference of the parasitic patch on the main radiation patch pattern. The length of the parasitic folded metal patch 140 can be 1 / 8 wavelength, and a shorter patch length can produce a higher resonant frequency. The position of the second through hole can accurately correspond to the position of the bending part of the parasitic folded metal patch 140, and be connected to the lower surface of the ground plane for feeding. In the embodiments of the present disclosure, by providing four L-shaped parasitic folded metal patches 140 at the four corners of the dielectric layer 200, the current distribution on the surface of the antenna can be changed, and the widening of the antenna beam can be realized. By setting the length of the parasitic folded metal patch 140 and connecting to the ground plane through the second through hole, better impedance matching can be achieved, the reflection loss can be reduced, the efficiency of the antenna can be improved, the bandwidth can be expanded, and directional radiation or the uniformity of omnidirectional radiation can be improved.

[0034] In some embodiments, the radiation patch 100 can be provided with two open slots 130, which can be rectangular in shape, with a length of 1.9-2.1 mm and a width of 1.4-1.6 mm. In the present disclosure, two rectangular open slots 130 can be uniformly provided, which can reduce the processing time and cost compared to more open slots, and to ensure the reliability of circularly polarized waves, the opening area of the two open slots in the present disclosure can be compared with the opening area when there are four open slots, and in cooperation with the size of the radiation patch 100 of the present disclosure, when the frequency is 8 GHz, the length of the rectangle can be 1.9-2.1 mm, and the width of the rectangle can be 1.4-1.6 mm, which can make the radiation patch 100 achieve better signal effect in limited space. In some embodiments, when the frequency is 8 GHz, the length of the open slot rectangle can be 2 mm, and the width of the rectangle can be 1.5 mm, so that it has a higher circular polarization effect. In the present disclosure, by increasing the area of the open slot rectangle (both the length and the width of the rectangle can be increased), the number of open slots is reduced (two are provided), thereby achieving better circular polarization effect, and the processing is convenient and the cost is low.

[0035] In some embodiments, the notch of the fan ring-shaped through slot 110 can face one open slot 130 and be away from the other open slot 130. In the present disclosure, the center of the fan ring-shaped through slot 110 is concentrically arranged with the radiation patch 100, and the center of the radiation patch 100 coincides with the center of the dielectric layer 200 and is centrally fed, thereby achieving better symmetry, facilitating the installation and implementation of the antenna array. After the circular center feeding of the radiation patch 100, the current passes through the notch of the fan ring-shaped through slot 110 to the two open slots 130 at different distances, which can improve the radiation performance. In the present disclosure, by facing one open slot 130 and being away from the other open slot 130 of the notch of the fan ring-shaped through slot 110, excellent impedance matching and radiation performance can be achieved while maintaining a low profile.

[0036] In some embodiments, the at least three through holes 120 can be uniformly arranged at the gap of the fan-shaped annular through groove 110. In the case of a certain gap of the fan-shaped annular through groove 110, the number of the through holes 120 can be appropriately increased according to the size of the gap of the fan-shaped annular through groove 110, so that the current distribution is more uniform. At least three, for example, three, five, seven, etc. can be provided. In some embodiments of the present disclosure, three through holes 120 can be provided to achieve more uniform current and lower processing difficulty. The three through holes 120 can be uniformly arranged so that the distance between each through hole 120 and the distance between the through holes 120 on both sides and the fan-shaped annular through groove 110 are substantially the same, so that the current is also more uniform and the processing cost is lower. In embodiments of the present disclosure, by providing at least three through holes 120 at the gap of the fan-shaped annular through groove 110, the shape of the antenna can be more symmetrical, and the gain pattern can be more uniform and symmetrical.

[0037] In some embodiments, the shape of the through hole 120 can be any one of a fan shape, a square shape, a circular shape, a triangular shape, or a fan-shaped annular shape. The through hole 120 can utilize the characteristics of different shapes to achieve different current distribution and flow direction. In embodiments of the present disclosure, the shape of the through hole 120 can be a fan shape or a fan-shaped annular shape, the outer arc shape of which can be the same as the outer radius of the fan-shaped annular through groove 110, and the radial length can also be consistent with the radial length of the fan-shaped annular through groove 110, so that the overall symmetry of the shape of the antenna is stronger, and the gain pattern is more uniform and symmetrical.

[0038] In some embodiments, the shape of the through hole 120 can be a fan shape, and the fan angle can be 9-13 degrees. In the case of a certain number of fans, the angle of the fan can be appropriately increased according to the size of the gap of the fan-shaped annular through groove 110, so that the area of the current conduction becomes smaller; and appropriately reducing can set more through holes 120. In embodiments of the present disclosure, the approximate angle of the gap of the fan-shaped annular through groove 110 is 90-100 degrees, and the through hole 120 can be provided as three. The through hole 120 is a fan shape and the angle of the fan shape can be 10 degrees, which can uniformly distribute the current. In embodiments of the present disclosure, by setting the angle of the fan shape to be more symmetrical, the conduction current can be more uniform.

[0039] In some embodiments, the inner circle radius of the fan ring-shaped through slot 110 can be 2.6 mm, the slot width of the fan ring-shaped through slot 110 can be 0.8 mm, the arc length angle of the fan ring-shaped through slot 110 can be 269 degrees, and the circular radius of the radiation patch can be 4.7 mm. In some scenarios, the circular radius of the radiation patch can be 4.6-4.8 mm, which can be set to 4.7 mm, for example, at a frequency of 8 GHz in the X band. The length of the rectangular opening slot 130 at the edge of the radiation patch can be 1.9-2.1 mm, and the width of the rectangular opening slot 130 can be 1.4-1.6 mm. The width of the rectangular opening slot 130 can be set to 1.5 mm, the length of the rectangular opening slot 130 can be set to 2 mm, the inner circle radius of the fan ring-shaped through slot 110 can be 2.5-2.7 mm, which can be set to 2.6 mm, and the slot width (radial direction) of the fan ring-shaped through slot 110 can be 0.7-0.9 mm, which can be set to 0.8 mm. The arc length angle of the fan ring-shaped through slot 110 can be 268-270 degrees, which can be set to 269 degrees. The notch of the fan ring-shaped through slot 110 can be provided with 3 fan-shaped through holes 120, and the angle of the fan-shaped through holes 120 can be 10 degrees. In the embodiments of the present disclosure, the radiation patch 100 improves the performance and uniformity of circularly polarized waves by setting the fan ring-shaped through slot 110 and the through hole 120, and in the case of a frequency of 8 GHz, the above size settings can provide the directional diagram with excellent wide-beam uniform radiation characteristics.

[0040] For example, by the above size settings, Figure 4 、 Figure 5 、 Figure 6 as shown, Figure 4 is a reflection coefficient diagram of a microstrip antenna, and the curve in the diagram is a curve of the reflection coefficient with respect to the frequency. It can be seen that the radiation patch covers 7.65 GHz-8.45 GHz with a reflection coefficient less than -10 dB.

[0041] Figure 5 is an 8 GHz E-plane radiation gain directional diagram, and the curves in the diagram are respectively a curve of the gain with respect to the elevation angle that can be achieved by the right-handed circular polarization at a frequency of 8 GHz when φ=0 degrees, a curve of the gain with respect to the elevation angle that can be achieved by the right-handed circular polarization at a frequency of 8 GHz when φ=45 degrees, and a curve of the gain with respect to the elevation angle that can be achieved by the right-handed circular polarization at a frequency of 8 GHz when φ=90 degrees. It can be seen that the 3dB gain beam width is greater than 91 degrees, and the difference in the antenna gain in each azimuth plane within the ±60 degree elevation angle is less than 0.45 dB.

[0042] Figure 6 is an 8 GHz E-plane circular polarization axial ratio directional diagram, and the curves in the diagram are respectively a curve of the axial ratio with respect to the elevation angle at a frequency of 8 GHz when φ=0 degrees, a curve of the axial ratio with respect to the elevation angle at a frequency of 8 GHz when φ=45 degrees, and a curve of the axial ratio with respect to the elevation angle at a frequency of 8 GHz when φ=90 degrees. It can be seen that the 3dB axial ratio beam width is greater than 179.5 degrees.

[0043] As shown in Figure 5 , Figure 6 , the radiation pattern has excellent wide-beam uniform radiation characteristics. The present scheme adopts a center-fed structure, and the antenna is symmetrically designed, has very good radiation pattern symmetry, and radiates uniformly. Meanwhile, the feed ports are arranged uniformly and regularly, which is conducive to scale arraying. The four parasitic structures effectively widen the beam width, especially the 3dB axial ratio beam width, which can meet the requirements of wide coverage and circular polarization characteristics. The antenna is a single-layer microstrip structure, which can effectively avoid the risk of delamination of the antenna in the harsh space environment with severe cold-heat alternation, effectively improve the reliability, and has extremely low profile and weight, which can save valuable satellite platform resources.

[0044] Based on the same inventive concept, the exemplary embodiments of the present disclosure also provide a spaceborne phased array antenna, wherein the spaceborne phased array antenna comprises: a plurality of microstrip antenna units according to any one of the preceding embodiments, wherein the plurality of microstrip antenna units are capable of cooperative radiation after being arrayed. A dielectric layer 200 is arranged below the radiation patch 100, and the center position penetrates a feed-through hole, connecting the circular radiation patch and the connector. Four ground metal through holes are located at the four corners of the edge of the dielectric layer 200, connecting the bending part of the parasitic folded metal patch and the ground plate. The microstrip antenna unit improves the performance and uniformity of circularly polarized waves through the fan ring-shaped through slot 110 and the through hole 120, and adopts a center-fed mode, and the feed ports are regularly and uniformly arranged, which is easy to scale arraying. The spaceborne phased array antenna combines electronic beam control with lightweight design through the cooperative radiation of the microstrip unit array. In the embodiments of the present disclosure, a plurality of microstrip antenna units are arranged for arraying, which is suitable for space tasks requiring high precision, high reliability and flexible beam management, has strong engineering implementation, and has wide application value. The antenna is symmetrically designed, has very good radiation pattern symmetry, and radiates uniformly. Meanwhile, the feed ports are arranged uniformly and regularly, which is conducive to scale arraying. The four parasitic structures effectively widen the beam width, especially the 3dB axial ratio beam width, which can meet the requirements of wide coverage and circular polarization characteristics. The antenna is a single-layer microstrip structure, which can effectively avoid the risk of delamination of the antenna in the harsh space environment with severe cold-heat alternation, effectively improve the reliability, and has extremely low profile and weight, which can save valuable satellite platform resources.

[0045] The present application uses specific words to describe the embodiments of the present application. As "one embodiment", "an embodiment", and / or "some embodiments" means a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "one alternative embodiment" mentioned in different places in the specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present application can be properly combined.

[0046] As used in the description of the application herein, the meaning of "a," "an," and "the" includes singular and plural referents unless the context clearly dictates otherwise. The terms "comprising," "including," "containing," and variations thereof do not specify an exhaustive or exhaustive disclosure, and these terms are each generally intended to be equivalent to the term "including," composed of the elements specified, without excluding other elements.

[0047] It should also be noted that, in the context of the present application, various features of the application will, in some instances, be presented in a form that is a combination of two or more separate features. Such presentation should not be interpreted as a limitation to the application. In addition, technical features of the application will, in some instances, be presented in a form that is a combination of two or more separate features. Such presentation should not be interpreted as a limitation to the application.

[0048] The foregoing description of the basic concepts of the application has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the application to the precise form disclosed. Many modifications, variations, and improvements will be apparent to practitioners skilled in this art. Such modifications, variations, and improvements are to be within the spirit and scope of the application.

Claims

1. A microstrip antenna element for use in a satellite-borne phased array antenna, wherein, The microstrip antenna unit comprises: a floor; a dielectric layer disposed on the floor; a radiation patch disposed above the dielectric layer, which is circular in shape, has a fan-shaped through slot arranged concentrically, and has at least two open slots arranged at the edge, and is used to form a circularly polarized wave through feeding; wherein the radiation patch is uniformly provided with at least three through holes at the openings of the fan-shaped through slot, forming a plurality of current paths from the feeding position of the radiation patch to the edge of the radiation patch; wherein the center of the radiation patch is located at the center of the dielectric layer, and the center of the dielectric layer is provided with a first through hole for feeding the center of the radiation patch; wherein the angle of the notch of the fan-shaped through slot is 90-100 degrees, and the shape of the through hole is a sector with an angle of 9-13 degrees.

2. The microstrip antenna element of claim 1, wherein, The dielectric layer is rectangular.

3. The microstrip antenna element of claim 2, wherein, The microstrip antenna unit further comprises: four parasitic folded metal patches, each disposed at a corner of the upper surface of the dielectric layer, and each in the shape of L; four second through holes are disposed at the L-shaped corners of the parasitic folded metal patches at the corners of the dielectric layer, and the four second through holes are connected to the floor, and the parasitic folded metal patches are in conduction with the floor through the second through holes.

4. The microstrip antenna element of claim 1, wherein, The radiation patch is provided with two open slots, and the shape of the open slot is a rectangle with a length of 1.9-2.1 mm and a width of 1.4-1.6 mm.

5. The microstrip antenna element of claim 4, wherein, The notch of the fan-shaped through slot faces one of the open slots and is away from the other open slot.

6. The microstrip antenna element of claim 1, wherein, The inner radius of the fan-shaped through slot is 2.6 mm, the slot width of the fan-shaped through slot is 0.8 mm, the arc length angle of the fan-shaped through slot is 269 degrees, and the radius of the circular radiation patch is 4.7 mm.

7. A space-borne phased array antenna, wherein, The space-borne phased array antenna comprises a plurality of microstrip antenna units as claimed in any one of claims 1-6, wherein the plurality of microstrip antenna units are capable of cooperative radiation.

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