Four-frequency common-aperture circularly polarized antenna structure unit and its array

Abstract

The present invention provides a four-frequency common-aperture circularly polarized antenna structure unit and its array, which provides four different operating frequencies for the antenna structure unit by setting four antenna units from two frequency bands through the common aperture, and improves the utilization rate of spectrum resources while maintaining the miniaturization of the antenna structure unit. Specifically, the present invention realizes the circular polarization characteristics while reducing the overall size of the antenna unit by respectively setting angle-added and / or angle-cut radiation patches in the four antenna units; at the same time, the direct-connected feeding structure and the coupled filter stripline feeding structure are simultaneously adopted in the antenna unit of the same frequency band, which realizes the antenna gain and broadband circular polarization in each frequency band, and improves the adaptability and flexibility of the antenna unit; by reasonably setting the operating frequency and feeding mode of the circularly polarized antenna unit in the antenna structure unit, signal crosstalk is avoided, and the effective integration of multi-band antennas is realized while maintaining the low profile characteristics.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic radiation technology, and more specifically, to a four-frequency co-aperture circularly polarized antenna structure unit and an array thereof. Background Art

[0002] With the rapid development of modern satellite communication technology, the performance requirements for satellite communication systems are constantly increasing. With the development trend of miniaturization, integration and multi-functional integration of satellite payloads, the research focus of satellite-borne phased array antennas has gradually shifted to the development of optimized antennas that take into account system volume and cost while achieving system functions and performance. In this context, coplanar antenna technology, as an innovative solution, has gradually received widespread attention.

[0003] The coplanar antenna technology integrates multiple antennas of different frequency bands in the same plane aperture. Its core advantage is that it can integrate multi-band antennas in a compact space. The integrated antennas can each have different structural forms, which distinguishes them from antenna units of the same structural form in traditional antenna arrays. This not only greatly saves the space occupied by the antenna and effectively reduces the complexity and cost of the system, but also provides the antenna structure with a wider operating frequency band and higher system flexibility without increasing additional space requirements.

[0004] However, there are still certain challenges when applying coplanar antenna technology to the design of satellite-borne phased array antennas. The biggest problem is how to ensure that the performance requirements of phased array antennas in two-dimensional large-angle scanning are met while integrating multiple frequency band antennas. In particular, the spacing design between antenna units needs to be strictly controlled within a range of less than half a wavelength to avoid the generation of grating lobes, which puts higher technical requirements on the design and manufacture of antennas. Although traditional laminated or three-dimensional array units have been effective in reducing antenna spacing, they are often accompanied by an increase in profile height, which is a disadvantage for application scenarios that pursue low-profile designs. Therefore, how to achieve effective integration of multi-band antennas while maintaining low-profile characteristics has become a key issue in current technology research and development. Summary of the invention

[0005] The present invention aims to overcome at least one of the above-mentioned deficiencies of the prior art and provide a circularly polarized antenna structure unit and an array thereof that realizes four-frequency co-aperture.

[0006] An object of the present invention is to provide a four-frequency co-aperture circularly polarized antenna structure unit, the antenna structure unit comprising a first frequency band antenna unit and a second frequency band antenna unit, the first frequency band antenna unit and the second frequency band antenna unit are coplanarly arranged, and the first frequency band antenna unit comprises a first antenna unit and a second antenna unit, and the second frequency band antenna unit comprises a third antenna unit and a fourth antenna unit;

[0007] The four antenna units respectively realize circular polarization by setting angle-added and / or angle-cut radiation patches; and in the first frequency band antenna unit and the second frequency band antenna unit, one antenna unit adopts direct connection feeding, and the other antenna unit adopts coupled filter stripline feeding;

[0008] The four antenna units are independently arranged, and in the first frequency band antenna unit and the second frequency band antenna unit, the operating frequency ratio between the two antenna units using direct connection feeding is consistent with the operating frequency ratio between the two antenna units using filter stripline feeding.

[0009] In the technical solution of the present application, four antenna units from two frequency bands and with different frequencies are arranged on the same antenna structure unit with a common aperture, thereby providing the antenna structure unit with four different operating frequencies. While maintaining the miniaturization of the antenna structure unit, the utilization rate of the spectrum resources is improved. At the same time, by reasonably setting the operating frequency and feeding mode of the circularly polarized antenna unit in the antenna structure unit, the polarization isolation of each antenna unit in the antenna structure unit is improved, signal crosstalk is avoided, the performance and communication stability of the antenna are improved, and while maintaining the low profile characteristics, the effective integration of multi-band antennas is achieved. Specifically, by respectively arranging angled and / or angled radiating patches in the four antenna units, the four antenna units are made to form a circularly polarized antenna unit. Specifically, by introducing angled and / or angled additions in the radiating patches in the antenna units as perturbation units, degenerate modes are excited to be generated in the antenna units, forming two or more linearly polarized electric fields with equal amplitudes and a phase difference of 90°, so that the antenna units radiate circularly polarized waves, thereby improving the performance and reliability of the antenna units by utilizing the circular polarization performance; and by angled and / or angled additions, the equivalent radiation length of the radiating patches can be effectively increased, thereby improving the radiation efficiency of the antenna units without increasing the physical size. While facilitating the reduction of the overall size of the antenna units, the shape and size of the angled and / or angled additions can be changed to improve better frequency selectivity, thereby improving the working performance of the antenna units in different frequency bands, so that the antenna units can maintain good radiation characteristics in multiple frequency bands. Furthermore, in order to achieve broadband circular polarization in each frequency band, in the first frequency band antenna unit and the second frequency band antenna unit, there is one antenna unit that uses direct connection feeding and the other antenna unit that uses coupled filter stripline feeding; specifically, in the antenna unit, by using direct connection feeding to directly connect the signal source to the antenna, not only the structure is simple and the system design is simplified, but also the generation of circularly polarized waves is promoted and the signal is transmitted to the maximum extent, and the loss of the signal during transmission is reduced, thereby improving the gain and directivity of the antenna unit, and at the same time improving the reliability and stability of the antenna structure unit as a whole; and in the other antenna unit of the same frequency band, a coupled filter feeding method is adopted, and by introducing a coupled feed stripline into the feeding network, the antenna unit has filtering response performance, effectively filters out electromagnetic waves in non-self-frequency bands, and reduces the coupling influence of other antenna units. At the same time, coupled filter feeding also facilitates fine adjustment of the impedance of the antenna unit, thereby significantly expanding the impedance bandwidth of the antenna unit, so that the antenna unit can maintain stable impedance matching in a wider frequency range, thereby improving the overall adaptability and flexibility of the antenna structure unit.

[0010] Furthermore, in order to improve the isolation between the antenna units in the antenna structure unit, the antenna structure unit can operate independently at its corresponding four operating frequencies, thereby improving the overall performance and stability of the antenna structure unit. Specifically, the four antenna units are independently arranged without mutual interconnection. At the same time, since the circularly polarized antenna also has rotational orthogonality, that is, there is a large polarization isolation between electromagnetic waves of different rotational directions, circularly polarized antenna units with different rotational directions are constructed in each antenna unit by introducing different radiation patches and feeding methods, thereby improving the polarization isolation between different antenna units and improving the overall signal transmission stability and anti-interference capability of the antenna structure unit. Moreover, preferably, in the first frequency band antenna unit and the second frequency band antenna unit, the operating frequencies of the two antenna units in the same frequency band are different, and the operating frequency ratio between the two antenna units using direct feeding is consistent with the operating frequency ratio between the two antenna units using filter stripline feeding, so that the operating frequencies of the multiple antenna units arranged in the same plane are set in multiples. By reasonably setting the frequency multiples of the multiple antenna units, not only the overall capacity and transmission efficiency of the antenna structure unit can be improved, but also the signal transmission quality can be optimized and interference can be reduced, thereby improving the overall performance of the antenna structure unit.

[0011] Preferably, in the technical solution, the first antenna unit is configured to include a plurality of first radiation patches and a first direct feed structure arranged from top to bottom, the first direct feed structure includes a first metallized via, and the first radiation patch and the metal floor are connected through the first metallized via;

[0012] The second antenna unit includes a plurality of second radiation patches and a first coupled filter stripline feeding structure arranged from top to bottom, the first coupled filter stripline feeding structure includes a second metallized via and a first coupled filter feed stripline, a gap is left between the first coupled filter feed stripline and the second radiation patch, and the second metallized via is connected to the first coupled filter feed stripline and the metal floor;

[0013] The third antenna unit includes a plurality of third radiation patches and a second direct feed structure arranged from top to bottom, wherein the second direct feed structure includes a third metallized via, and the third radiation patch and the metal floor are connected through the third metallized via;

[0014] The fourth antenna unit includes a plurality of fourth radiation patches and a second coupled filter stripline feeding structure arranged from top to bottom, the second coupled filter stripline feeding structure includes a fourth metallized via and a second coupled filter feed stripline, a gap is left between the second coupled filter feed stripline and the fourth radiation patch, and the fourth metallized via connects the second coupled filter feed stripline and the metal floor.

[0015] Furthermore, the second frequency band antenna unit is arranged at the center of the antenna structure unit, and the third antenna unit and the fourth antenna unit are coaxially stacked; the first frequency band antenna unit is symmetrically arranged with the second frequency band antenna unit as the center, and the first antenna unit and the second antenna unit are coplanarly arranged. In the technical solution of the present application, in the antenna structure unit, by making the third antenna unit and the fourth antenna unit coaxially stacked and making the first antenna unit and the second antenna unit coplanarly arranged, different antenna units are independently arranged, and at the same time, by taking into account both the horizontal arrangement and the vertical arrangement, not only the space utilization rate of the antenna structure unit is improved as much as possible, thereby reducing the size of the antenna structure unit, but also the radiation patches in different antenna units are conveniently arranged to form circular polarizations with different rotation directions, further improving the polarization isolation between antenna units, and ensuring that the four antenna units work independently and effectively.

[0016] Preferably, the antenna structure unit is arranged so that from top to bottom it is a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, a third metal layer, a third dielectric layer and a metal floor;

[0017] The first metal layer includes a first radiation patch, a second radiation patch and a third radiation patch;

[0018] The second metal layer includes a first coupled filter feed strip line and a fourth radiation patch;

[0019] The third metal layer includes a second coupled filter feed strip line. By making the antenna structure unit a stacked metal layer and a dielectric layer, so that it is consistent with the laminated structure of the PCB, the design of the laminated structure has a higher spatial design tolerance, and the filter strip line and the radiation patch are both metal layers on the PCB and can be set together on the same metal layer, thereby further reducing the cross-sectional size of the antenna structure unit, so that the antenna structure unit can achieve the goal of high miniaturization while maintaining its working performance; at the same time, all layers in the antenna structure unit can be made in one piece through the process flow of PCB production, saving the production process and being more economical.

[0020] Furthermore, the first radiation patch and the second radiation patch are both angled patches; the third radiation patch and the fourth radiation patch are both angled patches. By setting the radiation patch to an angle or an angle, the size of each radiation patch in each antenna unit is effectively reduced when responding to the set working frequency, which not only reduces the size of the antenna unit, but also improves the radiation efficiency and frequency response characteristics of the antenna unit, so that the antenna unit can be arranged more compactly in a limited space while ensuring its working performance, and realizes the miniaturization of the antenna structure unit as a whole, which is more in line with the application requirements of the satellite-borne phased array system.

[0021] Furthermore, the first coupled filter feed strip line and the second coupled filter feed strip line respectively include at least two parallel and unconnected microstrip lines. By using multiple coupled microstrip lines for feeding, the antenna impedance can be finely adjusted, thereby significantly expanding the impedance bandwidth of the antenna, while achieving filtering performance, increasing the isolation between antenna units, and reducing mutual interference between antennas of different frequencies, thereby improving the performance and reliability of the entire antenna structure unit.

[0022] In one of the embodiments, the antenna structure unit is a quadrangular prism whose plane shape is a square;

[0023] The first frequency band antenna unit includes four first antenna units and four second antenna units, wherein the first antenna units are respectively arranged at the four corners of the antenna structure unit, and the second antenna units are respectively arranged on the central cross line of the antenna structure unit;

[0024] The second frequency band antenna unit is arranged at the center of the antenna structure unit, and includes a third antenna unit and a fourth antenna unit stacked in sequence.

[0025] Furthermore, in the first antenna unit, the first radiating patch is an angled circular patch, which is a circular patch with an arc-shaped protrusion at the corner facing the square, and the angled circular patch is symmetrical about the diagonal of the square; not only is left-hand circular polarization achieved through the circular angled patch, but the axial ratio performance is also significantly improved through a 2×2 sequential rotation array, thereby improving the stability of the first antenna unit.

[0026] In the second antenna unit, the second radiation patch is a square patch with corners, and the square patch with corners is a square patch with square protrusions at the four corners, and the four second radiation patches are arranged on the central cross line of the antenna structure unit; not only right-hand circular polarization is achieved through the square corner patch, but also the axial ratio performance is significantly improved through the 2×2 sequential rotation array, thereby improving the stability of the second antenna unit.

[0027] In the third antenna unit, the third radiation patch is configured to be a square patch with two symmetrical triangles cut off at two opposite corners, thereby realizing right-hand circular polarization; at the same time, in the fourth antenna unit, the fourth radiation patch is configured to be a square patch with four symmetrical triangles cut off at four corners, and the fourth radiation patch is arranged at a position rotated 45° compared with the third radiation patch, thereby realizing left-hand circular polarization; further, due to the stacking design of the third radiation patch and the fourth radiation patch, the size of the fourth radiation patch is configured to be larger than the third radiation patch, so that in the second frequency band antenna unit, the fourth radiation patch can be used as a reference ground for the third radiation patch, and the third radiation patch can also be used as a guide plate for the fourth radiation patch, thereby improving the gain of the two antenna units, broadening the working bandwidth of the two, and further realizing broadband circular polarization in the two antenna units.

[0028] Furthermore, the first coupled filter feeding strip line and the second coupled filter feeding strip line are configured to include a linear strip line and an angled strip line respectively, and the linear strip line and the angled strip line are arranged in parallel and are not connected to each other;

[0029] In the second antenna unit and the second antenna unit, the second metallized via and the fourth metallized via are connected to the linear strip lines in the corresponding filter strip lines.

[0030] In the present technical solution, the filter stripline feeding structure includes a linear stripline and an angled stripline that are arranged in parallel and are not connected to each other, and a metallized via connected between the linear stripline and the metal floor. The stripline widths of the linear stripline and the angled stripline can be used to adjust the impedance matching of the antenna. By adjusting the sizes of the linear stripline and the angled stripline and their coupling gaps, specific frequency selection characteristics and polarization characteristics can be achieved in the antenna unit, thereby filtering out electromagnetic waves outside its own frequency band. At the same time, the circular polarization characteristics of the antenna unit can also be adjusted, thereby reducing the coupling influence of other antenna units, ensuring that each antenna unit works independently and effectively, and improving the reliability and stability of the antenna structure unit when working in multiple frequency bands.

[0031] Furthermore, the third metallized via penetrates the fourth radiation patch, and an air avoidance groove is provided on the fourth radiation patch at the penetration point of the third metallized via, and the size of the air avoidance groove is larger than the third metallized via; the provision of the air avoidance groove allows the third antenna unit and the fourth antenna unit to adopt a stacked and nested structure, which not only reduces the size of the second frequency band antenna unit, but also reduces the electromagnetic coupling between different antenna units, ensuring the isolation between different antenna units, so that the two antenna units can work independently of each other and ensure their working performance. Preferably, the third metallized via and the fourth metallized via are arranged diagonally in the second frequency band antenna unit so as to increase the spacing between the third metallized via and the fourth metallized via as much as possible, further reducing the coupling effect between the two antenna units and ensuring the independent working performance of the two antenna units.

[0032] Another object of the present invention is to provide a four-frequency co-aperture circularly polarized antenna array, which includes a receiving unit, a transmitting unit and an array arrangement of several four-frequency co-aperture circularly polarized antenna structure units as provided in the present technical solution, wherein each unit in the antenna array is integrated on a PCB.

[0033] In this technical solution, the receiving unit, the transmitting unit and several antenna structure units arranged in the array are integrally prepared to form an antenna PCB, and the phase between the antenna structure units is controlled by the receiving unit and the transmitting unit, thereby realizing two-dimensional large-angle scanning. In the antenna structure unit, there are two frequency bands and four frequency antenna units with a common aperture setting. The space utilization rate of the antenna structure unit is improved by two arrangement methods, namely, the coplanar setting and the coaxial setting. At the same time, the antenna gain is improved by the rotation setting of the radiation patch and the stacking setting of the radiation patch. The isolation between the antenna units is improved by the direct connection feeding and the coupling filter feeding method. While ensuring the miniaturization of the antenna structure unit, the effective integration of the four-frequency antenna unit is realized; further, by controlling the working frequency band of the antenna structure unit to match the transmitting unit and the receiving unit, the antenna PCB can realize large-angle scanning in the two-dimensional direction.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. A four-frequency co-aperture antenna structure unit is provided. Four antenna units from two frequency bands and with different frequencies are co-apertured on the same antenna structure unit, thereby providing the antenna structure unit with four different operating frequencies. While maintaining the miniaturization of the antenna structure unit, the utilization rate of spectrum resources is improved. At the same time, by reasonably setting the operating frequency and feeding mode of the circularly polarized antenna unit in the antenna structure unit, the polarization isolation of each antenna unit in the antenna structure unit is improved, signal crosstalk is avoided, the performance and communication stability of the antenna are improved, and while maintaining the low profile characteristics, the effective integration of multi-band antennas is achieved.

[0036] 2. By respectively setting angled and / or cut-angled radiating patches in the four antenna units to make the four antenna units form circularly polarized antenna units, the equivalent radiation length of the radiating patch is effectively increased, thereby improving the radiation efficiency of the antenna unit without increasing the physical size. While reducing the overall size of the antenna unit, it is also possible to provide the antenna unit with better frequency selectivity by changing the shape and size of the cut angle and / or the angled radiating patches, thereby improving the working performance of the antenna unit in different frequency bands.

[0037] 3. By using direct feeding in one antenna unit and coupled filter stripline feeding in the other antenna unit in the first frequency band antenna unit and the second frequency band antenna unit, antenna gain and broadband circular polarization are achieved in each frequency band, and the adaptability and flexibility of the antenna unit are improved.

[0038] 4. The four antenna units are set up independently without interconnection. At the same time, circularly polarized antenna units with different rotation directions are constructed in each antenna unit by introducing different radiation patches and feeding methods, thereby improving the polarization isolation between different antenna units and improving the overall signal transmission stability and anti-interference ability of the antenna structure unit.

[0039] 5. In the first frequency band antenna unit and the second frequency band antenna unit, the operating frequencies of the two antenna units in the same frequency band are different. The operating frequency ratio between the two antenna units using direct feeding is set to be consistent with the operating frequency ratio between the two antenna units using filter stripline feeding, so that the operating frequencies of the multiple antenna units arranged in the same plane are set in multiples. By reasonably setting the frequency multiples of the multiple antenna units, the overall capacity and transmission efficiency of the antenna structure unit are improved, and the signal transmission quality can be optimized and interference can be reduced, thereby improving the overall performance of the antenna structure unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is one of the structural schematic diagrams of the four-frequency co-aperture circularly polarized antenna structural unit of the present invention;

[0041] Figure 2 This is the second structural schematic diagram of the four-frequency co-aperture circularly polarized antenna structural unit of the present invention;

[0042] Figure 3 This is the third structural schematic diagram of the four-frequency co-aperture circularly polarized antenna structural unit of the present invention;

[0043] Figure 4 It is a schematic diagram of a coupled filter stripline feeding structure in a four-frequency co-aperture circularly polarized antenna structure unit of the present invention;

[0044] Figure 5 It is a schematic diagram of the filtering principle of the coupled filtering stripline feeding structure in the four-frequency co-aperture circularly polarized antenna structure unit of the present invention.

[0045] Explanation of the reference numerals: first antenna unit 100, first radiation patch 110, first metallized via 120, second antenna unit 200, second radiation patch 210, second metallized via 220, first coupling filter feed strip line 230, third antenna unit 300, third radiation patch 310, third metallized via 320, fourth antenna unit 400, fourth radiation patch 410, fourth metallized via 420, second coupling filter feed strip line 430, metal floor 500, avoidance groove 510, linear strip line 610, angled strip line 620, third metal layer 600, second metal layer 700, first metal layer 800. DETAILED DESCRIPTION

[0046] The drawings of the present invention are only for illustrative purposes and should not be construed as limiting the present invention. In order to better illustrate the following embodiments, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; it is understandable to those skilled in the art that some well-known structures and their descriptions in the drawings may be omitted.

[0047] Example 1

[0048] like Figure 1-Figure 3 As shown, this embodiment provides a four-frequency co-aperture circularly polarized antenna structure unit, the antenna structure unit includes a first frequency band antenna unit and a second frequency band antenna unit, the first frequency band antenna unit and the second frequency band antenna unit are coplanarly arranged, and the first frequency band antenna unit includes a first antenna unit 100 and a second antenna unit 200, and the second frequency band antenna unit includes a third antenna unit 300 and a fourth antenna unit 400; the four antenna units are independently arranged and not interconnected, thereby improving the isolation between the antenna units, so that the antenna structure unit can operate independently at its corresponding four operating frequencies.

[0049] Furthermore, the four antenna units respectively achieve circular polarization by setting an added angle and / or a cut angle radiation patch; by setting a cut angle and / or an added angle on the radiation patch, the equivalent radiation length of the radiation patch is effectively increased, thereby reducing the overall size of the antenna unit while providing the antenna unit with better frequency selectivity, thereby improving the working performance of the antenna unit in different frequency bands.

[0050] At the same time, in the first frequency band antenna unit and the second frequency band antenna unit, there is one antenna unit that uses direct connection feeding, and the other antenna unit that uses coupled filter stripline feeding, so that antenna gain and broadband circular polarization are achieved in each frequency band, and the adaptability and flexibility of the antenna unit are improved. In addition, in the first frequency band antenna unit and the second frequency band antenna unit, the operating frequency ratio between the two antenna units that use direct connection feeding is consistent with the operating frequency ratio between the two antenna units that use filter stripline feeding, so that the operating frequencies of the multiple antenna units set in the same plane are set in multiples. By reasonably setting the frequency multiples of the multiple antenna units, the overall capacity and transmission efficiency of the antenna structure unit are improved, and the signal transmission quality can be optimized and interference can be reduced, thereby improving the overall performance of the antenna structure unit.

[0051] Furthermore, the first antenna unit 100 includes a plurality of first radiation patches 110 and a first direct feed structure arranged from top to bottom, the first direct feed structure includes a first metallized via 120, and the first radiation patch 110 and the metal floor 500 are connected through the first metallized via 120;

[0052] The second antenna unit 200 includes a plurality of second radiation patches 210 and a first coupling filter stripline feeding structure arranged from top to bottom. The first coupling filter stripline feeding structure includes a second metallized via 220 and a first coupling filter feed stripline 230. A gap is left between the first coupling filter feed stripline 230 and the second radiation patch 210. The second metallized via 220 connects the first coupling filter feed stripline 230 and the metal floor 500.

[0053] The third antenna unit 300 includes a plurality of third radiation patches 310 and a second direct feed structure arranged from top to bottom, the second direct feed structure includes a third metallized via 320, and the third radiation patch 310 and the metal floor 500 are connected through the third metallized via 320;

[0054] The fourth antenna unit 400 includes a plurality of fourth radiation patches 410 and a second coupled filter stripline feeding structure arranged from top to bottom. The second coupled filter stripline feeding structure includes a fourth metallized via 420 and a second coupled filter feed stripline 430. A gap is left between the second coupled filter feed stripline 430 and the fourth radiation patch 410. The fourth metallized via 420 connects the second coupled filter feed stripline 430 and the metal floor 500.

[0055] Furthermore, the second frequency band antenna unit is arranged at the center of the antenna structure unit, and the third antenna unit 300 and the fourth antenna unit 400 are coaxially stacked; the first frequency band antenna unit is symmetrically arranged with the second frequency band antenna unit as the center, and the first antenna unit 100 and the second antenna unit 200 are coplanarly arranged. In the technical solution of the present application, in the antenna structure unit, by making the third antenna unit 300 and the fourth antenna unit 400 coaxially stacked and the first antenna unit 100 and the second antenna unit 200 coplanarly arranged, different antenna units are independently arranged, and at the same time, by taking into account both the horizontal arrangement and the vertical arrangement, the space utilization rate of the antenna structure unit is improved as much as possible, the size of the antenna structure unit is reduced, and the radiation patches in different antenna units are conveniently arranged to form circular polarizations with different rotation directions, further providing polarization isolation between antenna units, and ensuring that the four antenna units work independently and effectively.

[0056] Preferably, the antenna structure unit is arranged so that from top to bottom it is a first metal layer 800, a first dielectric layer, a second metal layer 700, a second dielectric layer, a third metal layer 600, a third dielectric layer and a metal floor 500; the first metal layer 800 includes a first radiation patch 110, a second radiation patch 210 and a third radiation patch 310; the second metal layer 700 includes a first coupling filter feed strip line 230 and a fourth radiation patch 410; the third metal layer 600 includes a second coupling filter feed strip line 430; by making the antenna structure unit a stacked metal layer and a dielectric layer, so that it is consistent with the stacked structure of the PCB, the coupling filter feed strip line and the radiation patch can be arranged together on the same metal layer, further reducing the cross-sectional size of the antenna structure unit; at the same time, all layers in the antenna structure unit can be integrally manufactured through the process flow of PCB manufacturing, saving the manufacturing process and being more economical.

[0057] Preferably, the first radiation patch 110 and the second radiation patch 210 are both angled patches; the third radiation patch 310 and the fourth radiation patch 410 are both angled patches. By setting the radiation patch to an angle or an angle, the size of each radiation patch in each antenna unit is effectively reduced when responding to the set working frequency, which not only reduces the size of the antenna unit, but also improves the radiation efficiency and frequency response characteristics of the antenna unit, so that the antenna unit can be arranged more compactly in a limited space while ensuring its working performance.

[0058] Furthermore, the first coupled filter feeding structure and the second coupled filter feeding structure respectively include at least two parallel and unconnected microstrip lines. By using multiple coupled microstrip lines for feeding, the antenna impedance can be finely adjusted, thereby significantly expanding the impedance bandwidth of the antenna, while achieving filtering performance, increasing the isolation between antenna units, and reducing mutual interference between antennas of different frequencies, thereby improving the performance and reliability of the entire antenna structure unit.

[0059] Example 2

[0060] With the development of communication systems, the requirements for antenna performance are getting higher and higher, driving antennas to develop in the direction of miniaturization and multi-band. Among them, the electromagnetic waves used by microwave antennas for satellite communications are generally in the microwave frequency band, and the frequency range is 1GHz to 40GHz. According to the frequency band, the microwave frequency band can be divided into: L, S, C, X, Ku, K, Ka band, and different frequency bands have different uses. Specifically, IEEE calls the 1-2GHz frequency band the L band, which is widely used in satellite positioning, satellite communications, and ground mobile communications; at the same time, the 2-4GHz frequency band is called the S band, which is mainly used for weather radar, marine radar, and satellite communications.

[0061] like Figure 1-Figure 5 As shown, this embodiment provides a four-band co-aperture circularly polarized antenna structure unit suitable for L and S frequency bands, which cleverly integrates two L-band antennas and two S-band antennas. Different from Embodiment 1, the L-band antenna includes a third antenna unit 300 and a fourth antenna unit 400, the S-band antenna includes a first antenna unit 100 and a second antenna unit 200, and the design frequencies of the L-band antenna and the S-band antenna are in a multiple relationship, wherein the frequency ratio of the L-band antenna to the S-band antenna is a specific multiple.

[0062] In this embodiment, the operating frequency of the first antenna unit 100 is 2.2 GHz, the operating frequency of the second antenna unit 200 is 2.1 GHz, and the operating frequency of the first antenna unit 100 is 100 MHz higher than that of the second antenna unit 200; the operating frequency of the third antenna unit 300 is 1.8 GHz, and the operating frequency of the fourth antenna unit 400 is 2.0 GHz. The operating frequency of the third antenna unit 300 is set to the lowest, and the operating frequency of the fourth antenna unit 400 is 200 MHz higher than that of the third antenna unit 300.

[0063] Specifically, the antenna structure unit is a quadrangular prism with a square plane shape; in the S-band antenna, it includes four first antenna units 100 and four second antenna units 200, the first antenna units 100 are respectively arranged at the four corners of the antenna structure unit, and the second antenna units 200 are respectively arranged on the central cross line of the antenna structure unit;

[0064] The L-band antenna is disposed at the center of the antenna structure unit, and includes a third antenna unit 300 and a fourth antenna unit 400 stacked in sequence.

[0065] Furthermore, in the first antenna unit 100, the first radiation patch 110 is an angled circular patch, which is a circular patch with an arc-shaped protrusion at the corner facing the square, and the angled circular patch is symmetrical about the diagonal of the square; not only is left-hand circular polarization achieved through the circular angled patch, but the axial ratio performance is also significantly improved through a 2×2 sequential rotation array, thereby improving the stability of the first antenna unit 100.

[0066] In the second antenna unit 200, the second radiation patch 210 is a square patch with corners, which is a square patch with square protrusions at the four corners, and the four second radiation patches 210 are arranged on the central cross lines of the antenna structure unit; not only right-hand circular polarization is achieved through the square corner patches, but also the axial ratio performance is significantly improved through the 2×2 sequential rotation array, thereby improving the stability of the second antenna unit 200.

[0067] In the third antenna unit 300, the third radiation patch 310 is configured to be a square patch with two symmetrical triangles cut off at two opposite corners, thereby realizing right-hand circular polarization; at the same time, in the fourth antenna unit 400, the fourth radiation patch 410 is configured to be a square patch with four symmetrical triangles cut off at four corners, and the fourth radiation patch 410 is arranged at a position rotated 45° compared with the third radiation patch 310, thereby realizing left-hand circular polarization; further, due to the stacking design of the third radiation patch 310 and the fourth radiation patch 410, the size of the fourth radiation patch 410 is configured to be larger than the third radiation patch 310, so that in the second frequency band antenna unit, the fourth radiation patch 410 can be used as a reference ground for the third radiation patch 310, and the third radiation patch 310 can also be used as a guide plate for the fourth radiation patch 410, thereby improving the gain of the two antenna units, broadening the working bandwidth of the two, and further realizing broadband circular polarization in the two antenna units.

[0068] The first coupled filter feed stripline 230 and the second coupled filter feed stripline 430 respectively include a linear stripline 610 and an angled stripline 620, and the linear stripline 610 and the angled stripline 620 are arranged in parallel and are not connected to each other; in the second antenna unit 200 and the second antenna unit 200, the second metallized via 220 and the fourth metallized via 420 are connected to the linear stripline 610 in the corresponding filter stripline. Preferably, the angle of the angled stripline 620 is 90°. Specifically, the coupled filter stripline feeding structure is as follows: Figure 4 As shown, the schematic diagram of the coupled filter stripline feed structure is as follows Figure 5 As shown, Z1 is the impedance of the metallized via portion, Z2 and Z3 are the impedances of the linear stripline 610 portion directly connected to the metallized via, Z4, Z5, and Z6 are the impedances of the coupled angled stripline 620 portion, the stripline Z1-Z2-Z3 portion generates a feeding signal with a 0° phase, and the stripline Z1-Z4-Z5-Z6 generates a feeding signal with a 90° phase shift through the coupled angled stripline 620 branches. At the same time, the coupled angled stripline 620 branches can generate zero points outside the band, thereby improving the out-of-band suppression characteristics, thereby achieving filtering performance. Furthermore, the impedance matching of the antenna unit can be adjusted by adjusting the strip line widths of the linear strip line 610 and the angled strip line 620. Thus, by adjusting the sizes of the linear strip line 610 and the angled strip line 620 and their coupling gaps, the selection characteristics and polarization characteristics at a specific frequency can be achieved in the antenna unit. At the same time, the circular polarization characteristics of the antenna unit can be optimized, and the coupling influence of other antenna units can be reduced, thereby ensuring that each antenna unit works independently and effectively.

[0069] Furthermore, the third metallized via 320 penetrates the fourth radiation patch 410, and an air avoidance groove 510 is provided on the fourth radiation patch 410 at the penetration point of the third metallized via 320, and the size of the air avoidance groove 510 is larger than the third metallized via 320; the provision of the air avoidance groove 510 allows the third antenna unit 300 and the fourth antenna unit 400 to adopt a stacked and nested structure, which not only reduces the size of the second frequency band antenna unit, but also reduces the electromagnetic coupling between different antenna units, ensuring the isolation between different antenna units, so that the two antenna units can work independently of each other and ensure their working performance. Preferably, the third metallized via 320 and the fourth metallized via 420 are arranged diagonally in the second frequency band antenna unit so as to increase the spacing between the third metallized via 320 and the fourth metallized via 420 as much as possible, further reducing the coupling effect between the two antenna units, and ensuring the independent working performance of the two antenna units.

[0070] Example 3

[0071] This embodiment provides a four-frequency co-aperture circular polarization antenna array, which includes a receiving unit, a transmitting unit and a plurality of four-frequency co-aperture circular polarization antenna structure units provided in Example 1 or Example 2, and each unit in the antenna array is integrated on a PCB; the phase between the antenna structure units is controlled by the receiving unit and the transmitting unit, thereby realizing two-dimensional large-angle scanning. In the antenna structure unit, there are two frequency bands and four frequency antenna units with co-aperture settings, and the space utilization rate of the antenna structure unit is improved by two arrangement modes of coplanar setting and coaxial setting. At the same time, the antenna gain is improved by the rotation setting of the radiation patch and the stacking setting of the radiation patch, and the isolation between the antenna units is improved by direct feeding and coupled filtering feeding. The effective integration of the four-frequency antenna unit is realized while ensuring the miniaturization of the antenna structure unit; further, by controlling the working frequency band of the antenna structure unit to match the transmitting unit and the receiving unit, the antenna PCB can realize large-angle scanning in two-dimensional directions.

[0072] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the claims of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A four-frequency common-aperture circularly polarized antenna structure unit, characterized in that: The antenna structure unit comprises a first frequency band antenna unit and a second frequency band antenna unit, and the first frequency band antenna unit and the second frequency band antenna unit are arranged in the same plane; The first frequency band antenna unit includes a first antenna unit with a direct feed structure and a second antenna unit with a coupled filter stripline feed structure; the second frequency band antenna unit includes a third antenna unit with a direct feed structure and a fourth antenna unit with a coupled filter stripline feed structure; the four antenna units respectively realize circular polarization by setting an angle-added and / or angle-cut radiation patch; The four antenna units are independently arranged, and in the first frequency band antenna unit and the second frequency band antenna unit, the operating frequency ratio between the two antenna units using direct connection feeding is consistent with the operating frequency ratio between the two antenna units using coupled filter strip line feeding; The second frequency band antenna unit is arranged at the center of the antenna structure unit, and the third antenna unit and the fourth antenna unit are coaxially stacked; The first frequency band antenna unit is symmetrically arranged with the second frequency band antenna unit as the center, and the first antenna unit and the second antenna unit are arranged in the same plane.

2. The circularly polarized antenna structure unit according to claim 1, characterized in that: The first antenna unit includes a plurality of first radiation patches and a first direct feed structure arranged from top to bottom, the first direct feed structure includes a first metallized via, and the first radiation patch and the metal floor are connected through the first metallized via; The second antenna unit includes a plurality of second radiation patches and a first coupled filter stripline feeding structure arranged from top to bottom, the first coupled filter stripline feeding structure includes a second metallized via and a first coupled filter feed stripline, a gap is left between the first coupled filter feed stripline and the second radiation patch, and the second metallized via is connected to the first coupled filter feed stripline and the metal floor; The third antenna unit includes a plurality of third radiation patches and a second direct feed structure arranged from top to bottom, wherein the second direct feed structure includes a third metallized via, and the third radiation patch and the metal floor are connected through the third metallized via; The fourth antenna unit includes a plurality of fourth radiation patches and a second coupled filter stripline feeding structure arranged from top to bottom, the second coupled filter stripline feeding structure includes a fourth metallized via and a second coupled filter feed stripline, a gap is left between the second coupled filter feed stripline and the fourth radiation patch, and the fourth metallized via connects the second coupled filter feed stripline and the metal floor.

3. The circularly polarized antenna structure unit according to claim 2, characterized in that: The antenna structure unit is composed of a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, a third metal layer, a third dielectric layer and a metal floor from top to bottom; The first metal layer includes a first radiation patch, a second radiation patch and a third radiation patch; The second metal layer includes a first coupled filter feed strip line and a fourth radiation patch; The third metal layer includes a second coupled filter feed strip line.

4. The circularly polarized antenna structure unit according to claim 2, characterized in that: The first radiation patch and the second radiation patch are both corner-added patches; the third radiation patch and the fourth radiation patch are both corner-cut patches.

5. The circularly polarized antenna structure unit according to claim 2, characterized in that: The first coupled filter feeding strip line and the second coupled filter feeding strip line respectively include at least two microstrip lines which are arranged in parallel and are not connected to each other.

6. The circularly polarized antenna structure unit according to any one of claims 2 to 5, characterized in that: The antenna structure unit is a quadrangular prism whose plane shape is a square; The first frequency band antenna unit includes four first antenna units and four second antenna units, wherein the first antenna units are respectively arranged at the four corners of the antenna structure unit, and the second antenna units are respectively arranged on the central cross line of the antenna structure unit; The second frequency band antenna unit is arranged at the center of the antenna structure unit, and includes a third antenna unit and a fourth antenna unit stacked in sequence.

7. The circularly polarized antenna structure unit according to claim 6, characterized in that: The first radiation patch is an angled circular patch, wherein the angled circular patch is a circular patch with an arc-shaped protrusion at a corner facing the square, and the angled circular patch is symmetrical about the diagonal line of the square; The second radiation patch is a square patch with corners, and the square patch with corners is a square patch with square protrusions at the four corners; The third radiation patch is a square patch with two symmetrical triangles cut off at two opposite corners, and the fourth radiation patch is a square patch with four symmetrical triangles cut off at four corners; The fourth radiation patch is arranged at a position rotated 45° relative to the third radiation patch, and the size of the fourth radiation patch is larger than that of the third radiation patch. The first coupled filter feeding strip line and the second coupled filter feeding strip line respectively include a linear strip line and an angled strip line, and the linear strip line and the angled strip line are arranged in parallel and are not connected to each other.

8. The circularly polarized antenna structure unit according to claim 7, characterized in that: The third metallized via penetrates the fourth radiation patch. An air avoidance groove is provided on the fourth radiation patch at the penetration point of the third metallized via. The size of the air avoidance groove is larger than that of the third metallized via.

9. A four-frequency common-aperture circularly polarized antenna array, characterized in that: It comprises a receiving unit, a transmitting unit and a plurality of four-frequency co-aperture circularly polarized antenna structure units as described in any one of claims 1 to 8 arranged in an array, wherein each unit in the antenna array is integrated on a PCB.

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