K / Ka frequency band broadband dual circularly polarized antenna for low-orbit satellite communication

Abstract

The invention relates to the technical field of wireless communication, and discloses a low orbit satellite communication K / Ka frequency band broadband dual circularly polarized antenna. According to the technical scheme, the antenna is characterized by comprising a radiation port surface, a resonant cavity, a dual-circular polarizer, a quasi-TEM transmission air cavity layer, a left polarization broadband feed network layer, a right polarization broadband feed network layer, a TEM mode conversion terminal, a polarization switch, a transceiving duplexer, a first standard waveguide port layer and a second standard waveguide port layer. The antenna is simple in structure, has a self-packaging characteristic, is good in electromagnetic compatibility, and can achieve the high gain, wide bandwidth and high circular polarization purity of the antenna. The shielding air cavity is formed by structure stacking and the metalized through holes, and when a plurality of circuits are integrated together, mutual interference is small, the structure is compact, assembling is convenient, and electrical performance is excellent.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and more specifically, to a K / Ka frequency band broadband dual circular polarization antenna for low-orbit satellite communication. Background Art

[0002] The use of circular polarization and co-aperture design in the prior art usually increases the complexity of the antenna system. For the antenna array, to improve the overall gain of the antenna, it is necessary to increase the aperture or number of the co-aperture units. Since the microstrip antenna itself has the characteristics of a low profile, this type of antenna is generally selected for design.

[0003] However, when microstrip antennas are arrayed, there are problems such as narrow antenna bandwidth, low working efficiency, and complex structure; especially when meeting the requirements of broadband dual circular polarization, the feeding network design is complex, which is not conducive to the design, processing and adjustment of the overall antenna.

[0004] Therefore, the present invention provides a low-orbit satellite communication K / Ka band broadband dual circularly polarized antenna, which improves the above-mentioned technical problems. Summary of the invention

[0005] The disclosed embodiments aim to address the deficiencies of the prior art and provide a low-orbit satellite communication K / Ka band broadband dual circularly polarized antenna. The invention has a simple structure, self-packaging characteristics, good electromagnetic compatibility, and can achieve high antenna gain, wide bandwidth, and high circular polarization purity. By using structural stacking and metallized through holes to form a shielded air cavity, when multiple circuits are integrated together, there is less mutual interference, a compact structure, easy assembly, and excellent electrical performance.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions: a low-orbit satellite communication K / Ka band broadband dual circular polarization antenna unit, comprising: a radiation aperture, a resonant cavity, a dual circular polarizer, a quasi-TEM transmission air cavity layer, a left-polarized broadband feeding network layer, a right-polarized broadband feeding network layer, a TEM mode conversion terminal, a polarization switch, a transceiver duplexer, a first standard waveguide port layer, and a second standard waveguide port layer;

[0007] The radiation aperture is formed by an array of 8×8 unit groups, and an isolation metal grid is provided in the radiation aperture of each unit group. The isolation metal grid divides the radiation aperture into four horn mouths to improve the directivity coefficient of the antenna.

[0008] The radiation port is located in a resonant cavity, and the resonant cavity is used to improve impedance matching;

[0009] A dual circular polarizer is provided below the resonant cavity, and the dual circular polarizer is composed of an array of 8×8 unit groups, each dual circular polarizer is composed of two input ports and one output port, the input end is composed of two identical rectangular waveguide ports, and the output end is a square waveguide;

[0010] A quasi-TEM transmission air cavity layer is provided below the dual circular polarizer, and a left-polarized broadband feeding network layer is provided below the quasi-TEM transmission air cavity layer; the quasi-TEM transmission air cavity layer and the left-polarized broadband feeding network layer are connected via a plurality of TEM mode conversion terminals; a first standard waveguide port layer is installed below the left-polarized broadband feeding network layer; a right-polarized broadband feeding network layer is provided below the first standard waveguide port layer; the first standard waveguide port layer and the right-polarized broadband feeding network layer are connected via a plurality of TEM mode conversion terminals; a second standard waveguide port layer is installed below the right-polarized broadband feeding network layer;

[0011] The upper surfaces of the left-polarized broadband feeding network layer and the right-polarized broadband feeding network layer are both provided with polarization switches;

[0012] The upper surfaces of the first standard waveguide port layer and the second standard waveguide port layer are both provided with transceiver duplexers.

[0013] As a preferred technical solution of the present invention, a metal isolation plate is installed on the inner surface of each dual circular polarizer; the dual circular polarizer can generate linear polarization or circular polarization with an arbitrary tilt angle by exciting two input ports through the metal isolation plate and at the same time with an appropriate phase relationship.

[0014] As a preferred technical solution of the present invention, the TEM mode conversion terminal is used to complete the mode conversion; when the TEM mode conversion terminal is a quasi-coaxial structure, different inner diameters are used at both ends of the TEM mode conversion terminal, and a quasi-TEM transmission air cavity is used to meet the change of antenna standing wave caused by impedance change during the mode conversion process, introduce additional transmission loss, and ensure the purity of electromagnetic waves transmitted inside the cavity.

[0015] As a preferred technical solution of the present invention, the isolation metal grid divides the radiation port surface into four horn ports, and the horn ports adopt a stepped gradient horn plus a cross grid structure. By adjusting the size and height of the port surface of each step of the stepped horn, the impedance matching of the horn antenna can be achieved; wherein the size and length of the waveguide correspond to the wave resistance of the guided mode; the calculation formula is as follows:

[0016]

[0017]

[0018] Among them, E u 、E vTransverse electric field; H u , H v transverse magnetic field; ε and μ are the dielectric constant and magnetic permeability of the medium respectively; ω is the angular frequency; β and κ are variable constants; λ and λ are c are the operating wavelength and the cut-off wavelength respectively; is the inherent impedance of the medium, and the air impedance

[0019] As a preferred technical solution of the present invention, the radiation aperture is composed of an array of 8×8 unit groups, and the condition for no grating lobe to appear in the array is:

[0020]

[0021] Where d is the spacing between unit antennas, λ is the wavelength in free space corresponding to the antenna operating frequency, and θ is the scanning angle of the antenna;

[0022] When the antenna is not scanning, θ = 0, and the condition for no grating lobe to appear is:

[0023] d<λ

[0024] The radiation aperture of the square antenna satisfies the following conditions for wave transmission:

[0025] λ<2L

[0026] Where L is the length of the radiation port.

[0027] As a preferred technical solution of the present invention, the calculation formula of the power reflected back to the input port of the dual circular polarizer and the power coupled to the non-excitation input port is:

[0028]

[0029] The relative amplitude and phase determine the axial ratio and the calculation formula of the main axis inclination of the elliptically polarized wave:

[0030]

[0031]

[0032] Where Γ is the reflection coefficient of odd-mode excitation, b i (i=1) represents the power reflected back to the input port, b i (i=2) indicates power coupling to the non-excitation input; b i (i=3) and b i The relative amplitude and phase of (i=4) determine the axial ratio and the major axis inclination of the elliptically polarized wave.

[0033] In summary, the present invention has the following beneficial effects:

[0034] First, wide bandwidth. The new form based on the combination of SISL feeding network and metal cavity ensures that this type of antenna can work normally within the K / Ka frequency band, has good impedance matching within the K / Ka frequency band, ensures mode purity, and further reduces the antenna efficiency and gain reduction caused by impedance mismatch.

[0035] Second, high integration. Due to the use of advanced feeding network structure, the input and output interfaces are diverse and flexible, which can be standard waveguide ports, coaxial or directly connected to TR components, with strong adaptability. Passive circuits and active circuits can be designed on this structure at the same time to achieve system integration, with a high degree of integration.

[0036] Third, it is small in size and compact in structure. The miniaturization problem is solved by loading, stacking and other measures; when connected and integrated with other circuit systems, part of the circuit can be placed at the bottom or top of the multi-layer substrate, making the overall structure more compact.

[0037] Fourth, easy assembly. The main structure of the antenna array is a lightweight alloy structure, which is assembled and installed by stacking and loading. There is no need for welding or debugging, and the assembly is simple and easy.

[0038] Fifth, the electrical performance is excellent. The novel antenna structure of the present invention can make the antenna work normally in the K / Ka frequency band, and the antenna unit and its array have a lower axial ratio, side lobe, and cross polarization, and have a higher aperture efficiency in the full frequency band.

[0039] Sixth, it has a large power capacity. Due to the new form of SISL feeding network combined with metal cavity, the antenna electromagnetic wave is transmitted in the cavity as a quasi-TEM mode, and the energy is bound inside the cavity and transmitted along the metal microstrip line and the cavity in the form of a quasi-TEM mode. The power capacity is equivalent to that of a conventional rectangular waveguide. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A three-dimensional exploded diagram of the internal structure of a low-orbit satellite communication K / Ka band broadband dual circularly polarized antenna provided in an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of a local structure provided by an embodiment of the present invention;

[0042] Figure 3 A schematic diagram of a four-terminal network structure provided by an embodiment of the present invention;

[0043] Figure 4 A schematic diagram of the partial structure of the radiation aperture and the dual circular polarizer provided in an embodiment of the present invention;

[0044] Figure 5A schematic diagram of a local structure of a quasi-TEM transmission air cavity layer provided in an embodiment of the present invention;

[0045] In the figure: radiation aperture 1, resonant cavity 2, dual circular polarizer 3, quasi-TEM transmission air cavity layer 4, left polarization broadband feeding network layer 5, right polarization broadband feeding network layer 6, TEM mode conversion terminal 7, polarization switch 8, transceiver duplexer 9, first standard waveguide aperture layer 10, second standard waveguide aperture layer 11. DETAILED DESCRIPTION

[0046] The present application is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements can also be made without departing from the concept of the present application. These all belong to the protection scope of the present application.

[0047] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0048] It should be noted that, if there is no conflict, the various features in the embodiments of the present application can be combined with each other, all within the scope of protection of the present application. In addition, although the functional module division is performed in the device schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in a sequence different from the module division in the device or the flow chart. In addition, the words "first", "second", "third", etc. used herein do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0049] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification and in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0050] In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0051] The disclosed embodiments are intended to solve the problems of narrow antenna bandwidth, low working efficiency, and complex structure when the microstrip antennas in the prior art are arrayed; in particular, the design of the feeding network is complex and not conducive to the design, processing and commissioning of the overall antenna for the demand for broadband dual circular polarization. In view of this, the disclosed embodiments propose a low-orbit satellite communication K / Ka band broadband dual circularly polarized antenna. The antenna has a simple structure and self-packaging characteristics, good electromagnetic compatibility, and can achieve high antenna gain, wide bandwidth, and high circular polarization purity. The shielded air cavity is formed by structural stacking and metallized through-holes. When multiple circuits are integrated together, there is less mutual interference, a compact structure, easy assembly, and excellent electrical performance.

[0052] Please refer to Figure 1-2 , Figure 1-2 The schematic diagram of the structure of the K / Ka band broadband dual circular polarization antenna for low-orbit satellite communication according to the embodiment of the present disclosure is shown. It includes: a radiation aperture 1, a resonant cavity 2, a dual circular polarizer 3, a quasi-TEM transmission air cavity layer 4, a left-polarized broadband feeding network layer 5, a right-polarized broadband feeding network layer 6, a TEM mode conversion terminal 7, a polarization switch 8, a transceiver duplexer 9, a first standard waveguide port layer 10, and a second standard waveguide port layer 11;

[0053] The radiation aperture 1 is composed of 8×8 units (in a square, every 4 apertures form a unit), forming a 64-unit array antenna; Figure 4 As shown, an isolation metal grid is provided in the radiation aperture 1 of each unit group, and the isolation metal grid divides the radiation aperture 1 into four trumpet-shaped surfaces, and the trumpet-shaped surfaces are used to improve the uniform distribution of current, thereby improving the current distribution and increasing the directivity coefficient of the antenna;

[0054] The radiation aperture 1 is located in the resonant cavity 2. The resonant cavity 2 ensures that the antenna has good impedance matching within the K / Ka frequency band, ensures mode purity, and further reduces the decrease in antenna efficiency and gain caused by impedance mismatch.

[0055] A dual circular polarizer 3 is provided below the resonant cavity 2. The dual circular polarizer 3 is composed of an array of 8×8 unit groups. Each dual circular polarizer 3 is composed of two input ports and one output port. The input end is composed of two identical rectangular waveguide ports, and the output end is a square waveguide. Figure 4 As shown, a metal isolation plate is installed on the inner surface of each dual circular polarizer 3; the dual circular polarizer 3 can generate linear polarization or circular polarization with an arbitrary tilt angle by exciting two input ports through the metal isolation plate and at the same time with an appropriate phase relationship; so that the broadband polarizer has the characteristics of wide bandwidth and low axial ratio.

[0056] A quasi-TEM transmission air cavity layer 4 is provided below the dual circular polarizer 3. Figure 5As shown, a left-polarized broadband feeding network layer 5 is provided below the quasi-TEM transmission air cavity layer 4; the quasi-TEM transmission air cavity layer 4 and the left-polarized broadband feeding network layer 5 are connected via a plurality of TEM mode conversion terminals 7; a first standard waveguide port layer 10 is installed below the left-polarized broadband feeding network layer 5; a right-polarized broadband feeding network layer 6 is provided below the first standard waveguide port layer 10; the first standard waveguide port layer 10 and the right-polarized broadband feeding network layer 6 are connected via a plurality of TEM mode conversion terminals 7; a second standard waveguide port layer 11 is installed below the right-polarized broadband feeding network layer 6;

[0057] The TEM mode conversion terminal 7 is used to complete the mode conversion, that is, quasi-TEM mode-TEM mode-TE01 / TE10. When the TEM mode conversion terminal 7 is a quasi-coaxial structure, different inner diameters are used at both ends of the TEM mode conversion terminal 7, and the quasi-TEM transmission air cavity layer 4 is used to meet the change of the antenna standing wave caused by the impedance change during the mode conversion process, introduce additional transmission loss, and ensure the purity of the electromagnetic wave transmission inside the cavity (no additional electromagnetic wave transmission forms of other modes will be introduced).

[0058] Polarization switches 8 are provided on the upper surfaces of the left polarization broadband feeding network layer 5 and the right polarization broadband feeding network layer 6;

[0059] Transceiver duplexers 9 are disposed on the upper surfaces of the first standard waveguide port layer 10 and the second standard waveguide port layer 11 .

[0060] After the antenna unit completes the impedance and polarization matching of the unit, it is necessary to cooperate with the 6-level left-polarized broadband feeding network and the right-polarized broadband feeding network to effectively transmit the antenna energy, and cooperate with the quasi-TEM transmission air cavity layer 4 to form a complete air cavity. The multi-level broadband network completes the coaxial waveguide TEM mode-quasi-TEM mode transmission air cavity conversion and then outputs the signal, thereby completing the distribution of microwave energy; at the same time, cooperate with the polarization switch 8 and the transceiver duplexer 9 to complete the signal division and switching, and finally the standard waveguide port receives and transmits the signal.

[0061] The radiator of the unit antenna of the present invention adopts a stepped gradient horn plus a cross grid structure, and the impedance matching of the horn antenna can be achieved by adjusting the size and height of the aperture of each step of the stepped horn;

[0062] Specifically, the wave resistance of the guided mode corresponding to the waveguide size and length is calculated; the calculation formula is as follows:

[0063]

[0064]

[0065] Among them, E u 、E v Transverse electric field; H u, H v transverse magnetic field; ε and μ are the dielectric constant and magnetic permeability of the medium respectively; ω is the angular frequency; β and κ are variable constants; λ and λ are c are the operating wavelength and the cut-off wavelength respectively; is the inherent impedance of the medium, and the air impedance

[0066] According to the above formula, it can be known that for the square array antenna of the present invention, the antenna radiates inside the radiation cavity and the matching condition is that the impedance transformation is matched from 50Ω to 376.7Ω.

[0067] The conditions for the array to not have grating lobes are:

[0068]

[0069] Where d is the spacing between the unit antennas, λ is the wavelength in free space corresponding to the antenna operating frequency (i.e., the antenna operating wavelength), and θ is the scanning angle of the antenna. When the antenna is not scanning, θ = 0, and the condition for no grating lobe to appear is:

[0070] d<λ

[0071] For the radiation aperture 1 of the square antenna of the present invention, the conditions for wave transmission are:

[0072] λ<2L

[0073] Wherein L is the length of the radiation aperture 1.

[0074] The circular polarizer of the present invention consists of two input ports and one output port. The input port consists of two identical rectangular waveguide ports, and the output port is a square waveguide. By adding an additional metal isolation plate and simultaneously exciting the two input ports with an appropriate phase relationship, linear polarization or circular polarization with an arbitrary tilt angle can be generated. Figure 3 The four-terminal network shown establishes the relationship between the network parameters for the symmetry of the structure.

[0075] For this structure, the traveling wave inside the cavity can be described as a i and b i (where i = 1, 2, 3, 4), where a i and b i (where i=1, 2, 3, 4) the amplitudes of the incident and reflected waves.

[0076] When the even mode is excited in the rectangular waveguide region (i.e., a1=a2=1, a3=a4=0), the electric and magnetic field distributions in the upper and lower rectangular waveguides are the same, but the current phase directions on the two side walls are opposite. Therefore, the metal groove on the common wall between the two waveguides will not interfere with the field distribution in the waveguide. The flow direction of the current in the conductor is fixed, so if the current directions of the two conductors are opposite, then the flow direction of the current in the first conductor is opposite to that in the second conductor, that is, the phase difference is 180° and the amplitude is canceled. In fact, the propagation of the even mode wave can transfer all the energy to the TE10 mode of the rectangular waveguide.

[0077] When the odd mode is excited in the rectangular waveguide region (i.e. a1=1, a2=-1, a3=a4=0), the upper and lower waveguides are reversed compared to the even mode case. The current is distributed on the top and bottom surface sidewalls in the same direction and the grooves on the lower sidewalls, which will cause interference of the field, resulting in mode coupling and reflection. Therefore, the odd mode energy will be partially transferred to the TE01 mode in the square waveguide and partially;

[0078] Specifically, the power reflected back to the input port and the power coupled to the non-excited input port are calculated as follows:

[0079]

[0080] The relative amplitude and phase determine the axial ratio and the calculation formula of the main axis inclination of the elliptically polarized wave:

[0081]

[0082]

[0083] Where Γ is the reflection coefficient of odd-mode excitation, b i (i=1) represents the power reflected back to the input port (can also be expressed by the standing wave ratio VSWR), b i (i = 2) indicates the power coupled to the non-stimulated input, which determines the isolation between ports. i (i=3) and b i The relative amplitude and phase of (i=4) determine the axial ratio and the major axis inclination of the elliptically polarized wave.

[0084] For a perfectly circularly polarized wave, b i (i=3) and b i (i=4) The amplitude and phase difference must be equal to 90°. Therefore, the essence of the design process is to find the minimum reflection coefficient of Γ in odd mode excitation, and the output phase angle is as close to 90° as possible.

[0085] The present invention verifies that 8×8 unit groups form a 64-unit array antenna, which can cover the K / Ka frequency band, has 4 ports for left and right transmission and reception (both K / Ka frequency bands have left and right rotation), the port standing waves are all within 1.5, the circular polarization axial ratio is less than 1.0, the antenna gain is greater than 26dB, and the port isolation is greater than 55dB. Among them, the left and right rotation input ports are a new form based on the combination of SISL feeding network and metal cavity, completing TE01-quasi-TEM mode-TEM mode-TE01 / TE10 form conversion and energy transfer. In summary, the broadband dual circularly polarized antenna of the present invention has the characteristics of high gain, high efficiency and low axial ratio.

[0086] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A low-orbit satellite communication K / Ka band broadband dual circular polarization antenna, characterized in that: include: Radiation aperture (1), resonant cavity (2), dual circular polarizer (3), quasi-TEM transmission air cavity layer (4), left polarization broadband feeding network layer (5), right polarization broadband feeding network layer (6), TEM mode conversion terminal (7), polarization switching (8), transceiver duplexer (9), first standard waveguide aperture layer (10), and second standard waveguide aperture layer (11); The radiation aperture (1) is composed of an array of 8×8 unit groups, and an isolation metal grid is provided inside the radiation aperture (1) of each unit group. The isolation metal grid divides the radiation aperture (1) into four horn ports, so as to improve the directivity coefficient of the antenna; The radiation port surface (1) is located in a resonant cavity (2), and the resonant cavity (2) is used to improve impedance matching; A dual circular polarizer (3) is provided below the resonant cavity (2), the dual circular polarizer (3) being composed of an array of 8×8 unit groups, each dual circular polarizer (3) being composed of two input ports and one output port, the input end being composed of two identical rectangular waveguide ports, and the output end being a square waveguide; A quasi-TEM transmission air cavity layer (4) is provided below the dual circular polarizer (3); a left-polarized broadband feeding network layer (5) is provided below the quasi-TEM transmission air cavity layer (4); the quasi-TEM transmission air cavity layer (4) and the left-polarized broadband feeding network layer (5) are connected via a plurality of TEM mode conversion terminals (7); a first standard waveguide port layer (10) is installed below the left-polarized broadband feeding network layer (5); a right-polarized broadband feeding network layer (6) is provided below the first standard waveguide port layer (10); the first standard waveguide port layer (10) and the right-polarized broadband feeding network layer (6) are connected via a plurality of TEM mode conversion terminals (7); a second standard waveguide port layer (11) is installed below the right-polarized broadband feeding network layer (6); The upper surfaces of the left-polarized broadband feeding network layer (5) and the right-polarized broadband feeding network layer (6) are both provided with polarization switches (8); The upper surfaces of the first standard waveguide port layer (10) and the second standard waveguide port layer (11) are both provided with transceiver duplexers (9).

2. A low-orbit satellite communication K / Ka band broadband dual circular polarization antenna according to claim 1, characterized in that: A metal isolation plate is installed on the inner surface of each dual circular polarizer (3); the dual circular polarizer (3) can generate linear polarization or circular polarization with an arbitrary tilt angle by exciting two input ports through the metal isolation plate and at the same time with an appropriate phase relationship.

3. A low-orbit satellite communication K / Ka band broadband dual circular polarization antenna according to claim 1, characterized in that: The TEM mode conversion terminal (7) is used to complete mode conversion; when the TEM mode conversion terminal (7) is a quasi-coaxial structure, different inner diameters are used at both ends of the TEM mode conversion terminal (7), and a quasi-TEM transmission air cavity is used to meet the change of antenna standing waves caused by impedance changes during the mode conversion process, introduce additional transmission losses, and ensure the purity of electromagnetic waves transmitted inside the cavity.

4. The low-orbit satellite communication K / Ka band broadband dual circular polarization antenna according to claim 1, characterized in that: The isolation metal grid divides the radiation aperture (1) into four horn apertures, wherein the horn apertures adopt a stepped gradient horn plus a cross grid structure, and the impedance matching of the horn antenna can be achieved by adjusting the aperture size and height of each step of the stepped horn; wherein the size and length of the waveguide correspond to the wave resistance of the guided mode; the calculation formula is as follows: Among them, E u 、E v Transverse electric field; H u , H v transverse magnetic field; ε and μ are the dielectric constant and magnetic permeability of the medium respectively; ω is the angular frequency; β and κ are variable constants; λ and λ are c are the operating wavelength and the cut-off wavelength respectively; is the inherent impedance of the medium, and the air impedance 5. The low-orbit satellite communication K / Ka band broadband dual circular polarization antenna according to claim 1, characterized in that: The radiation aperture (1) is composed of an array of 8×8 unit groups, and the condition for the array to not have grating lobes is: Where d is the spacing between unit antennas, λ is the wavelength in free space corresponding to the antenna operating frequency, and θ is the scanning angle of the antenna; When the antenna is not scanning, θ = 0, and the condition for no grating lobe to appear is: d<λ The radiation aperture (1) of the square antenna satisfies the following conditions for wave transmission: λ<2L Where L is the length of the radiation aperture (1).

6. The low-orbit satellite communication K / Ka band broadband dual circular polarization antenna according to claim 1, characterized in that: The power reflected back to the input port of the dual circular polarizer (3) and the power coupled to the non-excited input port are calculated as follows: The relative amplitude and phase determine the axial ratio and the calculation formula of the main axis inclination of the elliptically polarized wave: Where Γ is the reflection coefficient of odd-mode excitation, b i (i=1) represents the power reflected back to the input port, b i (i=2) indicates power coupling to the non-excitation input; b i (i=3) and b i The relative amplitude and phase of (i=4) determine the axial ratio and the major axis inclination of the elliptically polarized wave.

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