A circularly polarized integrated feed transmission array antenna based on degenerate mode waveguide

Abstract

The present invention discloses a circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide, comprising an array face and a planar feed located below the array face, wherein the phase center of the planar feed coincides with the focus of the array face. The array face comprises multiple array face units, each of which comprises an upper section, a middle section, and a lower section. The upper section and the lower section are located at both ends of the middle section in a mirror-image manner and each has a horn-shaped opening structure with a linearly gradient inner diameter. The multiple array face units include multiple types of array face units, and the inner diameters of the middle sections of different types of array face units are different. The array face simultaneously meets the requirements of the Fermat principle and circularly polarized radiation. The planar feed is a differentially fed planar aperture antenna, comprising a feeding structure for feeding, a waveguide, a horn-shaped waveguide, a rectangular cavity, and a patch structure located within the rectangular cavity, wherein the patch structure is connected to the horn-shaped waveguide. The array face does not require the introduction of dielectric materials, and the use of a planar aperture antenna as a feed source can make the entire transmission array antenna have a high aperture efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and in particular relates to a circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide. Background Art

[0002] In recent years, with the continued growth of millimeter-wave communication research, transmission array antennas have attracted widespread attention from both academia and industry. These antennas typically offer advantages such as high gain, simple feeding, and low feeding loss, making them well-suited for various applications in the millimeter-wave frequency band. Regarding polarization, circularly polarized transmission array antennas are a worthy research area, as they effectively avoid polarization mismatch and suppress multipath effects. They also have significant practical application value.

[0003] The circularly polarized transmission array antenna mainly consists of two parts: the array and the feed. For the former, there are two main design methods commonly used in the literature reported so far: the first type is the combination of a polarizer and a phase shifter, as shown in literature [1]-[2], in which the polarizer is used to convert the linearly polarized wave emitted by the feed into a circularly polarized wave, and then the focused beam is realized through the phase shifter. The second type is a unit using a receive-transmit structure (Rx-Tx), in which the receiving unit (Rx) is located below the array and is used to receive the linearly polarized wave emitted by the feed, and then the transmitting unit (Tx) generates circularly polarized radiation. The unit phase shift is usually achieved by changing the relative angle between the receiving and transmitting units, as shown in literature [3]-[4]. For the feed part, almost all the reported literature uses a linearly polarized horn antenna as the feed. In view of the current technical status, the circularly polarized transmission array antenna still has some shortcomings: First, the array design in the existing schemes inevitably uses dielectric materials, and the introduction of dielectric materials will cause dielectric loss in the array. Because the aperture efficiency of a transmission array antenna is closely related to the array's surface loss, high loss reduces the antenna's aperture efficiency. Furthermore, horn antennas generally suffer from the drawbacks of being large, heavy, difficult to manufacture, high cost, and difficult to integrate with front-end circuits. These issues significantly limit the practical application of transmission array antennas. Furthermore, there are currently relatively few design solutions for circularly polarized transmission array antennas.

[0004] literature:

[0005] [1] G.B. Wu, Y.-S. Zeng, K.F. Chan, S.-W. Qu, and C.H. Chan, "High-gain circularly polarized lens antenna for terahertz applications," IEEE Antennas Wireless Propag. Lett., vol. 18, no. 5, pp. 921-925, May 2019.

[0006] [2] M.N. Iqbal, M.F.M. Yusoff, M.K.A. Rahim, M.R. Bin Hamid, Z. Johari, and H.U. Rahman, "Circularly polarized transmitarray antenna design using meander line polarizer for Ku-band applications," IEEE Access, vol. 9, pp. 119598-119612, 2021.

[0007] [3] L.D. Palma, A. Clemente, L. Dussopt, R. Sauleau, P. Potier, and P. Pouliguen, "Circularly-polarized reconfigurable transmitarray in Ka-band with beam scanning and polarization switching capabilities," IEEE Trans. Antennas Propag., vol. 65, no. 2, pp. 529-540, Feb. 2017.

[0008] [4] L. Di Palma, A. Clemente, L. Dussopt, R. Sauleau, P. Potier, and P. Pouliguen, "Circularly polarized transmitarray with sequential rotation in Ka-band," IEEE Trans. Antennas Propag., vol. 63, no. 11, pp. 5118-5124, Nov. 2015. Summary of the Invention

[0009] In order to solve at least one of the problems in the prior art, namely, high dielectric loss and low aperture efficiency in the array surface part caused by the introduction of dielectric materials, and large volume, heavy weight, difficult processing, high cost, and difficulty in integration with front-end circuits of the feed part caused by the use of horn antennas as feed sources, the present invention provides a circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide.

[0010] In order to achieve the purpose of the present invention, the present invention provides a circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide, comprising an array face and a planar feed located below the array face, wherein the phase center of the planar feed coincides with the focus of the array face.

[0011] The array includes multiple array units, each of which includes an upper section, a middle section, and a lower section. The upper section and the lower section are located at both ends of the middle section in a mirrored manner, and both have a trumpet-shaped opening structure with a linearly gradient inner diameter. The multiple array units include multiple types of array units, and the inner diameters of the middle sections of different types of array units are different. The array also meets the requirements of Fermat's principle and circularly polarized radiation.

[0012] The planar feed source is a differentially fed planar aperture antenna, comprising a feeding structure for feeding, a waveguide, a horn-shaped waveguide connected to the waveguide, a rectangular cavity, and a patch structure located in the rectangular cavity, wherein the patch structure is connected to the horn-shaped waveguide.

[0013] Furthermore, the planar feed illuminates the array surface vertically and forms a 45-degree angle with the array surface in the horizontal direction.

[0014] Furthermore, the four patch structures are arranged in a 2×2 linear array.

[0015] Furthermore, there are multiple patch structures in the rectangular cavity, each patch structure includes a first microstrip line, a second microstrip line connected to the first microstrip line, and a third microstrip line connected to the second microstrip line. The first microstrip line is connected to the horn-shaped waveguide, the second microstrip line is used to adjust the impedance matching of the antenna, and the impedance matching of the antenna can be adjusted by changing its length and width. The third microstrip line is a radiation structure, and changing the offset distance L between it and the first microstrip line can achieve adjustment of the E-plane and H-plane beam widths.

[0016] Furthermore, each array unit is an air-filled rectangular waveguide structure.

[0017] Furthermore, the array includes a plurality of array units arranged in a linear form.

[0018] Furthermore, among the multiple types of array face units included in the plurality of array face units, different types of array face units have different phase types.

[0019] Furthermore, the types of array units in the plurality of array units are divided using 3-bit phase quantization, that is, there are 8 types of array units.

[0020] Furthermore, according to Fermat's principle, the phase shift required for each array unit is:

[0021]

[0022] Among them, x and y represent the coordinates of the geometric center of a certain array element on the array in the x direction and y direction, F represents the focal length of the array, Represents an arbitrary initial phase; there are two orthogonal electric field modes in the array unit, namely the polarization degenerate TE 10 and TE 01 mode, their phase shift magnitudes within the unit can be expressed as and To satisfy Fermat's principle, we need to or One of the two is equal to

[0023] In order to satisfy the circular polarization radiation principle, these two phases must also satisfy the following equations:

[0024]

[0025] Furthermore, the linearly polarized electromagnetic wave generated by the planar feed can be decomposed into two orthogonal components with equal amplitude and phase, and these two components respectively excite the polarization degenerate TE in the array element. 10 and TE 01 mode, and their phase constants are

[0026]

[0027] f is the center frequency of the antenna, β TE10 and β TE01 Represents TE 10 and TE 01 The phase constant of the mode in the middle section of the array unit, a and b are the length and width of the inner diameter of the middle section of the array unit, μ0 and ε0 are the magnetic permeability and dielectric constant of the air, respectively.

[0028] The phase changes of the two modes in the middle section of the waveguide are:

[0029]

[0030] The phase difference between the modes is:

[0031]

[0032] Where h is the height of the middle section of the array unit;

[0033] By adjusting the parameters a, b, and h, the array can simultaneously meet the requirements of Fermat's principle and circularly polarized radiation.

[0034] Compared with the prior art, the present invention can achieve at least the following beneficial effects:

[0035] 1. The array unit adopts an air-filled rectangular waveguide structure, which does not introduce dielectric loss and therefore has extremely low transmission loss.

[0036] 2. The feed is a single-layer planar feed with high gain and wide bandwidth. It can replace the traditional horn antenna in terms of performance. It also has the advantages of low cost, light weight, low profile and easy integration.

[0037] 3. In one embodiment, the entire transmission array antenna has excellent performance, with a gain of 29.3dBic, a bandwidth of 17.7%, and an aperture efficiency of up to 49.4%, which is technically superior to the current circularly polarized transmission array antenna.

[0038] 4. The planar aperture antenna proposed in the present invention can be used in conjunction with the proposed array surface, so that the entire transmission array antenna can have a higher aperture efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the overall structure of a circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide provided by an embodiment of the present invention.

[0040] Figure 2 Schematic diagram of the structure of the array unit in an embodiment of the present invention.

[0041] Figure 3 2 is a schematic diagram of the front structure of the feed source in an embodiment of the present invention.

[0042] Figure 4 2 is a schematic diagram of the back structure of the feed source in an embodiment of the present invention.

[0043] Figure 5 2 is a schematic structural diagram of a patch structure in an embodiment of the present invention.

[0044] Figure 6 is the TE of each array unit in the embodiment of the present invention 10 Schematic diagram of the transmission loss of the mode.

[0045] Figure 7 is the TE of each array unit in the embodiment of the present invention 01 Schematic diagram of the transmission loss of the mode.

[0046] Figure 8 Schematic diagram of the impedance matching characteristics of the planar feed according to an embodiment of the present invention.

[0047] Figure 9 Figures (a) and (b) are the E-plane radiation pattern and H-plane radiation pattern at the center frequency of the planar feed source of an embodiment of the present invention, respectively.

[0048] Figure 10 Schematic diagram showing how the gain of a planar feed varies with frequency according to an embodiment of the present invention.

[0049] Figure 11 Schematic diagram of the impedance matching characteristics of the transmission array antenna in an embodiment of the present invention.

[0050] Figure 12 Schematic diagram of the axial ratio characteristics of the transmission array antenna in an embodiment of the present invention.

[0051] Figure 13 It is the XZ plane radiation pattern of the transmission array antenna in the embodiment of the present invention at a center frequency of 30 GHz.

[0052] Figure 14 It is the YZ plane radiation pattern of the transmission array antenna at a center frequency of 30 GHz in the embodiment of the present invention.

[0053] Figure 15 Schematic diagram of the gain characteristics of the transmission array antenna in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] See also Figure 1-5 The present invention provides a circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide, comprising an array face 1 and a planar feed 2 located below the array face 1, with a bracket 3 used to fix the two together. The rectangular coordinate system is established as follows: Figures 1 to 5 As shown, the XY plane of the coordinate system is parallel to array face 1, with the x-axis and y-axis parallel to the edges of array face 1, and the z-axis pointing in the direction of the electromagnetic wave perpendicular to the array face. Planar feed 2 illuminates array face 1 perpendicularly and forms a 45-degree angle with array face 1 in the horizontal direction (XY plane). The phase center of planar feed 2 coincides with the focal point of array face 1.

[0056] The array 2 includes a plurality of array units 4 arranged in a linear form, wherein the plurality of array units 4 include multiple types of array units, and the inner diameters of the middle sections of different array units are different. The array 1 satisfies the requirements of both the Fermat principle and circularly polarized radiation. In some embodiments of the present invention, each array unit 4 is an air-filled rectangular waveguide structure, such as Figure 2 As shown, each array unit 4 includes three sections: upper, middle and lower. The upper and lower sections are trumpet-shaped opening structures with linearly gradient inner diameters, and are located at both ends of the middle section in a mirror-image manner.

[0057] If the entire array requires 360-degree continuous phase shifting, corresponding array elements are required to achieve this. Theoretically, there is an infinite number of array elements, and the types of array elements are determined by the phase type. In some embodiments of the present invention, there are eight types of array elements 4, using 3-bit phase quantization, corresponding to eight types of array elements. It is understood that in other embodiments, the number of array element types may be fewer or more than eight.

[0058] Wherein, corresponding to 3-bit phase quantization, the outer cross-section of each array element 4 is square, and the overall size is 0.9λ0×0.9λ0×4.6λ0, where λ0 represents the free space wavelength at the center frequency.

[0059] Different types of array elements 4 have different inner diameters a×b of the middle section. The specific size can be selected by simulation using the full-wave simulation software ANSYS HFSS. The selection principle must meet 1) Fermat's principle; 2) circularly polarized radiation principle.

[0060] First, according to Fermat's principle, the phase shift required for each array element 4 is:

[0061]

[0062] Wherein, x and y represent the coordinates of the geometric center of a certain array element on array 1 in the x-direction and y-direction, and F represents the focal length of array 1. Indicates an arbitrary initial phase; there are two orthogonal electric field modes in the array element 4, namely the polarization degenerate TE 10 and TE 01 mode, their phase shift magnitudes within the unit can be expressed as and To satisfy Fermat's principle, we need to or One of the two is equal to On the other hand, in order to satisfy the circular polarization radiation principle, these two phases must also satisfy the following equations:

[0063]

[0064] The planar feed 2 is a single-layer PCB structure. In some embodiments of the present invention, Figure 3 and Figure 4 Shown are the front and back structures of the planar feed 2, respectively. The PCB thickness is 1.575 mm, the material is Rogers RT / duroid 5880, the dielectric constant is 2.2, and the loss tangent is 0.0009.

[0065] The planar feed 2 is a differentially fed planar aperture antenna comprising a feed structure 5, two sections of waveguides 6, two sections of horn waveguides 7, a rectangular cavity 8, and four patch structures 9. The waveguides 6 and horn waveguides 7 are connected. In some embodiments of the present invention, the four patch structures 9 are arranged in a 2×2 pattern and are mirror-imaged within the rectangular cavity 8.

[0066] See also Figure 5 In some embodiments of the present invention, each patch structure 9 includes a cascaded first microstrip line 10, a second microstrip line 11, and a third microstrip line 12. The first microstrip line 10 in the patch structure 9 is connected to the horn-shaped waveguide 7 to achieve electrical connection between the patch and the waveguide structure. The second microstrip line 11 is used to adjust the impedance matching of the antenna. The impedance matching of the antenna can be adjusted by changing its length and width. The third microstrip line 12 is a radiating structure. By changing the offset distance L between it and the first microstrip line 10, the E-plane and H-plane beam widths can be adjusted.

[0067] In some embodiments of the present invention, the planar feed 2 is fed by a WR-28 coaxial-waveguide converter at the feeding structure 5 .

[0068] In terms of working principle, the feeding structure 5 is similar to the E-plane T-junction waveguide power divider in terms of working principle, which can divide the electromagnetic wave into two equal-amplitude, anti-phase signals. The differential signal is transmitted to the horn-shaped waveguide 7 via the waveguide waveguide 6, and then distributed to the four patch structures 9 with equal amplitude by the horn-shaped waveguide 7, and finally radiated into the atmosphere. Since the four patch structures 9 are arranged in a mirror image, the differential electromagnetic waves can constructively interfere in the +z direction to achieve unidirectional radiation to illuminate the array 1. The use of differential feeding in the planar feed 2 can make the phase center of the feed more stable and coincide with the geometric center of the feed structure. The function of the rectangular cavity 8 is to suppress the surface waves in the dielectric plate, thereby making the electromagnetic energy more concentrated.

[0069] Since there is a 45° relative angle between the planar feed 2 and the array 1, according to the vector decomposition principle, the linearly polarized electromagnetic wave generated by the planar feed 2 can be decomposed into two orthogonal components with equal amplitude and phase. These two components respectively excite the polarization degenerate TE in the array element 4. 10 and TE01 mode, and their phase constants are

[0070]

[0071] Where f is the center frequency of the antenna, β TE10 and β TE01 Represents TE 10 and TE 01 The phase constant of the mode in the middle section of the array element, a, b are the length and width of the inner diameter of the middle section of the array element 4, μ0 and ε0 are the magnetic permeability and dielectric constant of the air, respectively. Therefore, the phase changes of the two modes in the middle section of the waveguide are:

[0072]

[0073] Where h is the height of the middle section of the array element. Therefore, the phase difference between the modes is:

[0074]

[0075] The above equations show that the phase variation between the two modes within array element 4 can be achieved by varying the waveguide inner diameters a and b, as well as the height h. By adjusting these three structural parameters, array element 1 can simultaneously meet the Fermat principle and the requirements for circularly polarized radiation. In transmission array design, all phase discussions concern the relative phase between elements, and the upper and lower sections of different array elements 4 are identical. Therefore, only the effect of the middle section on phase is considered here. The upper and lower sections primarily serve as transitions for electromagnetic waves and have little effect on phase variation.

[0076] In some embodiments of the present invention, a 13×13 array arrangement is used, with a total of 169 units, an aperture size of 117mm×117mm, a focal length of 117mm, and a focal diameter ratio of 1. The array 1 is processed using metal 3D printing technology, and the minimum wall thickness of the array unit 4 is 0.3mm. The phase quantization of the array 1 adopts a 3-bit solution, that is, a cycle of 360° is discretized into 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°. The inner diameters a and b of the middle sections of the eight array units 4 are shown in Table 1. TE in the eight array units 4 10 and TE 01 The transmission losses of the modes are Figure 6 and Figure 7 As shown, it can be seen that within the antenna operating frequency band (27.3-32.6 GHz, 17.7%), the average loss is about 0.4 dB, which is far superior to the current technical level.

[0077] Table 1

[0078]

[0079] In terms of antenna performance, the performance of the planar feed 2 is as follows: Figures 8 to 10 shown. Figure 8 For impedance matching characteristics, the planar feed 2 can achieve broadband matching below -10dB in the frequency band of 26.7-33.6GHz, with a bandwidth of about 23%. The E-plane and H-plane directional patterns at the center frequency are as follows: Figure 9 As shown in the figure, it can be seen that the feed has good unidirectional radiation characteristics. At the same time, the 3-dB beamwidths of the two surfaces are close, indicating that the planar feed 2 can achieve relatively uniform illumination on the array surface. Figure 10 The figure shows a schematic diagram of gain variation with frequency. It can be seen that the planar feed 2 has a relatively high gain, with a peak gain of 15.5 dBi, a stable in-band gain, and a fluctuation of less than 3 dB.

[0080] The performance of the entire transmission array antenna is as follows Figures 11 to 15 As shown. Among them, Figure 11 The impedance matching characteristic of the transmission array antenna can achieve an impedance matching lower than -10dB in the frequency band of 27-33GHz, which has broadband characteristics. Figure 12 As shown, the axial ratio is lower than 3 dB in the frequency band of 27.3-32.6 GHz, and the axial ratio bandwidth is about 17.7%. Figure 13 and Figure 14 These are the E-plane and H-plane radiation patterns with a center frequency of 30 GHz. The antenna sidelobe is lower than -18 dB, which means that it achieves high gain while also having the characteristics of low sidelobe. Figure 15 The gain characteristics are as follows: within the operating frequency band (27.3-32.6GHz), the maximum gain is 29.3dBic, and the 3dB gain bandwidth covers the operating bandwidth, with stable in-band gain performance. At the same time, the maximum aperture efficiency in the band is as high as 49.4%, which has very high aperture efficiency.

[0081] The transmission array antenna provided by the above embodiment of the present invention adopts an air-filled rectangular waveguide structure in its array surface portion, and utilizes the polarization degeneracy characteristics of the rectangular waveguide to stimulate TE 10 and TE 01 These two modes constitute the two orthogonal linear polarization components required for circularly polarized radiation. Since no dielectric material is involved, there is no dielectric loss in the array part, and thus it has a higher aperture efficiency. As for the feed part, the traditional planar aperture antenna has not yet been applied to the design of transmission array feed. The planar aperture antenna proposed in the present invention can be used in conjunction with the proposed array. The 3-dB beam widths of the E-plane and the H-plane are similar, which can provide more uniform electromagnetic wave illumination for the array, further improving the aperture efficiency. The feed has the advantages of low profile, light weight, easy processing, easy integration, and low cost, and can replace the traditional horn antenna feed.

[0082] In summary, the transmission array antenna has a wide axial ratio bandwidth, high gain, and high aperture efficiency, and its overall performance is better than the current circularly polarized transmission array antenna.

[0083] The parts not involved in the present invention are the same as the existing technology or are implemented by using the existing technology.

[0084] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Those skilled in the art may make various equivalent changes and improvements based on the above embodiment. All equivalent changes and modifications made within the scope of the claims shall fall within the scope of protection of the present invention.

Claims

1. A circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide, characterized in that: It includes an array surface (1) and a planar feed source (2) located below the array surface (1), wherein the phase center of the planar feed source (2) coincides with the focus of the array surface (1). The array surface (1) includes a plurality of array surface units (4), each array surface unit includes an upper section, a middle section and a lower section, the upper section and the lower section are located at both ends of the middle section in a mirrored manner, and both are trumpet-shaped opening structures with linearly gradient inner diameters, the plurality of array surface units (4) include a variety of array surface units, and the inner diameters of the middle sections of different types of array surface units are different, and the array surface (1) satisfies the requirements of the Fermat principle and circularly polarized radiation at the same time; The planar feed source (2) is a differentially fed planar aperture antenna, comprising a feeding structure (5) for feeding, a waveguide (6), a horn-shaped waveguide (7) connected to the waveguide (6), a rectangular cavity (8), and a patch structure (9) located in the rectangular cavity (8), wherein the patch structure (9) is connected to the horn-shaped waveguide (7); According to Fermat's principle, the phase shift required for each array element (4) is: ； Where x and y represent the coordinates of the geometric center of a certain array element on the array (1) in the x-direction and y-direction, and λ0 represents the free space wavelength at the center frequency; represents the focal length of the array (1), Indicates an arbitrary initial phase; there are two orthogonal electric field modes in the array element (4), namely the polarization degenerate TE 10 and TE 01 mode, their phase shift magnitudes within the unit can be expressed as and , to satisfy Fermat's principle, we need to let or One of the two is equal to ; In order to satisfy the circular polarization radiation principle, these two phases must also satisfy the following equations: 。 2. The circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide according to claim 1, characterized in that: The plane feed source (2) illuminates the array surface (1) vertically and forms a 45-degree angle with the array surface (1) in the horizontal direction.

3. The circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide according to claim 1, characterized in that: There are four patch structures (9) in the rectangular cavity (8), and each patch structure (9) includes a first microstrip line (10), a second microstrip line (11) connected to the first microstrip line (10), and a third microstrip line (12) connected to the second microstrip line (11). The first microstrip line (10) is connected to the horn-shaped waveguide (7). The second microstrip line (11) is used to adjust the impedance matching of the antenna. The impedance matching of the antenna can be adjusted by changing its length and width. The third microstrip line (12) is a radiation structure. By changing the offset distance L between the third microstrip line (12) and the first microstrip line (10), the E-plane and H-plane beam widths can be adjusted.

4. The circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide according to claim 3, characterized in that: The four patch structures (9) are arranged in a 2×2 linear array.

5. The circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide according to claim 1, characterized in that: Each array unit (4) is an air-filled rectangular waveguide structure.

6. The circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide according to claim 1, characterized in that: The array (1) comprises a plurality of array units (4) arranged in a linear form.

7. The circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide according to claim 1, characterized in that: Among the multiple array units included in the plurality of array units (4), different types of array units have different phase types.

8. The circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide according to claim 7, characterized in that: The types of array units in the plurality of array units (4) are divided using 3-bit phase quantization, that is, there are 8 types of array units.

9. The circularly polarized integrated feed transmission array antenna based on a degenerate mode waveguide according to claim 1, characterized in that: The linearly polarized electromagnetic wave generated by the planar feed (2) can be decomposed into two orthogonal components with equal amplitude and phase. These two components respectively excite the polarization degenerate TE in the array element (4). 10 and TE 01 mode, and their phase constants are is the center frequency of the antenna, and Respectively represent TE 10 and TE 01 The phase constant of the mode in the middle section of the array element, a and b are the length and width of the inner diameter of the middle section of the array element (4), respectively. and denote the magnetic permeability and dielectric constant of air respectively, then The phase changes of the two modes in the middle section of the waveguide are: The phase difference between the modes is: Where h is the height of the middle section of the array unit; By adjusting the parameters a, b, and h, the array (1) can simultaneously meet the requirements of Fermat's principle and circularly polarized radiation.

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