Circularly polarized antenna with broadband axial ratio beam broadening
By combining the circular dichroic selection absorption surface with the antenna frame and using a rectangular frame with a notch for conformal design, the problem of difficulty in optimizing frequency points in the frequency band in the existing technology is solved, and the axis-specific beam broadening and gain improvement in the entire frequency band is achieved, meeting the high-performance needs of modern communication systems.
Patent Information
- Application Number
- CN202411767664.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-03-25
AI Technical Summary
While achieving broadband axes-to-beam broadening technology, it is difficult to maintain good axes-to-beam broadening characteristics at all frequencies throughout the entire frequency band, resulting in limited applications in high data rates and complex environments.
By combining the circular dichroic selective absorption surface with the antenna frame and using a rectangular frame with a notch, it is designed in a conformal manner with the radiating antenna, selective absorption of left-hand circular polarization and right-hand circular polarization is achieved.
It significantly improves the gain to axis ratio beam width of the signal, expands the axis ratio beam bandwidth in the entire frequency band, ensuring that performance improvements are maintained in a wider range of applications and meeting diverse communication needs.
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Figure CN119695515A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of wireless communications, and in particular relates to a circularly polarized antenna with broadband axial ratio beam broadening. Background Art
[0002] Circularly polarized antennas, with their unique radiation characteristics, can significantly improve the coverage and penetration of signals, especially when faced with challenges such as multipath propagation and signal attenuation. Therefore, they play a key role in modern communication systems, especially in satellite communications, mobile communications, and drone communications. However, in recent years, with the rapid growth in demand for wireless communications, especially driven by 5G and future 6G networks, traditional circularly polarized antennas have gradually revealed their problems of insufficient bandwidth and limited beam width control capabilities. In order to address these challenges, circularly polarized antennas with wide-bandwidth axial ratio beamwidth have emerged. The wide-bandwidth axial ratio beam characteristic further improves the transmission stability of the signal, reduces the impact of polarization on communication quality, and enhances anti-interference capabilities, becoming an important technology to meet diverse communication needs.
[0003] However, broadband axial ratio beam broadening technology still faces some challenges. Although innovations in design and materials have achieved certain results, designers often find it difficult to take into account all frequencies within the bandwidth, especially in achieving broadband while maintaining good axial ratio beam broadening characteristics at all frequencies within the bandwidth. Existing materials and structural designs often perform well in certain frequency bands. Specifically, they can usually only achieve optimization of three or four frequencies, but may lead to performance degradation in a wider range of applications. This limits the application of circularly polarized antennas in specific high data rates and complex environments, affecting their applicability in modern communication systems.
[0004] Therefore, finding an effective method to solve the problem of achieving beam broadening within the wide bandwidth of the antenna so that it can achieve beam broadening within the entire frequency band is an important issue currently faced. It will also lay the foundation for the use of broadband axial ratio beam broadening circularly polarized antennas in a wider range of application scenarios and promote the further development of wireless communication technology. Summary of the invention
[0005] The present invention provides a broadband axial ratio beam broadening circular polarization antenna. The design combines a circular dichroism selective absorption surface with an antenna frame to selectively absorb left-hand circular polarization and right-hand circular polarization, and the polarization selective absorption frame is designed as a conformal rectangular frame with a notch, which not only greatly improves the gain, but also expands the axial ratio beam bandwidth in the full frequency band. The design uses only simple manufacturing materials and innovative design ideas to take into account the axial ratio beam broadening of all frequency points within a wide bandwidth, maintain performance improvement in a wider range of applications, and meet diverse communication needs.
[0006] The technical solution to realize the present invention is: a circularly polarized antenna with broadband axial ratio beam broadening, which can realize beam bandwidth broadening in the full frequency band, including an external conformal frame, an internal circularly polarized antenna located at the center of the external conformal frame, a circular dichroism polarization selective absorption surface designed on the external conformal frame, and an upper frame metal boundary and a lower frame metal boundary located on the upper and lower surfaces of the external conformal frame; the internal circularly polarized antenna includes, from top to bottom, an upper dielectric substrate with metal strips, an Al2O3 dielectric resonator, and a lower dielectric substrate with a feeding structure, and the metal ground of the external conformal frame and the internal circularly polarized antenna are on the same horizontal plane.
[0007] The external conformal frame is a rectangular frame with inner notches in the middle of the four sides. Three circular dichroism polarization selective absorption surfaces are evenly distributed on the inner wall surface of the inner notch on each side, and two raised parts on both sides of the inner notch are each distributed with two circular dichroism polarization selective absorption surfaces.
[0008] Compared with the prior art, the present invention has the following significant advantages: the present invention combines the circular dichroism selective absorption surface with the antenna frame, and adopts a rectangular frame with a notch, which is conformally designed with the radiating antenna, thereby achieving effective selective absorption of left-hand circular polarization and right-hand circular polarization, significantly improving the gain and axial ratio beam width of the signal, and expanding the axial ratio beam width in the full frequency band; the present invention only uses simple manufacturing materials, and through innovative design ideas, it achieves the goal of maintaining performance improvement in a wider bandwidth application range. This design that achieves axial ratio beam broadening and high gain in a broadband range enables the antenna of the present invention to meet the stringent requirements of modern wireless communication systems for high-performance antennas, and promotes the continuous advancement of communication technology. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figure 1 It is a three-dimensional stereogram of the circularly polarized antenna with broadband axial ratio beam broadening of the present invention.
[0010] Figure 2 The top view of the circularly polarized antenna with broadband axial ratio beam broadening of the present invention.
[0011] Figure 3 The three-dimensional structure of the absorbing surface is selected for circular dichroism polarization in the present invention.
[0012] Figure 4 The bottom view of the circularly polarized antenna with broadband axial ratio beam broadening of the present invention is shown.
[0013] Figure 5 It is a schematic diagram of the selective absorption degree of left-handed and right-handed polarization of the circular dichroism polarization selective absorption surface in the present invention.
[0014] Figure 6 The circularly polarized antenna with broadband axial ratio beam broadening of the present invention has a |S11 |Atlas.
[0015] Figure 7 It is the axial ratio spectrum of the circularly polarized antenna with broadband axial ratio beam broadening of the present invention.
[0016] Figure 8 It is the gain spectrum of the circularly polarized antenna with broadband axial ratio beam broadening of the present invention.
[0017] Fig. 9 A comparison of the 3 dB axial ratio beamwidth at 4.2 GHz using a circular dichroism polarization selective absorption surface conformal frame compared to a metal frame for the present invention.
[0018] Fig.10 A comparison of the 3 dB axial ratio beamwidth at 4.4 GHz using a circular dichroism polarization selective absorption surface conformal frame compared to a metal frame for the present invention.
[0019] Fig.11 A comparison of the 3 dB axial ratio beamwidth at 4.6 GHz using a circular dichroism polarization selective absorption surface conformal frame compared to a metal frame for the present invention.
[0020] Fig.12 A comparison of the 3 dB axial ratio beamwidth at 4.8 GHz using a circular dichroism polarization selective absorption surface conformal frame compared to a metal frame for the present invention.
[0021] Fig.13 A comparison of the 3 dB axial ratio beamwidth at 5.0 GHz using a circular dichroism polarization selective absorption surface conformal frame compared to a metal frame for the present invention.
[0022] Fig.14 A comparison of the 3 dB axial ratio beamwidth at 5.2 GHz using a circular dichroism polarization selective absorption surface conformal frame compared to a metal frame for the present invention.
[0023] Fig.15 A comparison of the 3 dB axial ratio beamwidth at 5.4 GHz using a circular dichroism polarization selective absorption surface conformal frame compared to a metal frame for the present invention.
[0024] Fig.16 A comparison of the 3 dB axial ratio beamwidth at 5.6 GHz using a circular dichroism polarization selective absorption surface conformal frame compared to a metal frame for the present invention.
[0025] Fig.17 Schematic diagram of the present invention in the xoz and yoz planes at 5.0 GHz.
[0026] In the figure: 1-external conformal frame; 2-circular dichroism polarization selective absorption surface; 3-resistance; 4-upper frame metal boundary; 5-lower frame metal boundary; 6-upper dielectric substrate; 7-metal strip; 8-Al2O3 dielectric resonator; 9-metal ground; 10-lower dielectric substrate; 11-feeding microstrip line. DETAILED DESCRIPTION
[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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 creative work are within the scope of protection of the present invention.
[0028] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0029] The technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.
[0030] The following will further introduce the specific implementation method, as well as the technical difficulties and inventive points of this invention in combination with this design example.
[0031] Combine the following Figure 1 to Figure 17 The invention provides a circularly polarized antenna with broadband axial ratio beam broadening.
[0032] A circularly polarized antenna with broadband axial ratio beam broadening can achieve full-band beam bandwidth broadening, comprising an external conformal frame 1, an internal circularly polarized antenna located at the center of the external conformal frame 1, a circular dichroism polarization selective absorption surface 2 designed on the external conformal frame 1, an upper frame metal boundary 4 and a lower frame metal boundary 5 located on the upper and lower surfaces of the external conformal frame 1; the internal circularly polarized antenna comprises, from top to bottom, an upper dielectric substrate 6 with a metal strip 7, an Al2O3 dielectric resonator 8, and a lower dielectric substrate 10 with a feeding structure, and the external conformal frame 1 and a metal ground 9 of the internal circularly polarized antenna are on the same horizontal plane.
[0033] The external conformal frame 1 is a rectangular frame with inner notches in the middle of the four sides, and three circular dichroism polarization selective absorption surfaces 2 are evenly distributed on the inner wall surface of the inner notch on each side, and two raised parts on both sides of the inner notch are each distributed with two circular dichroism polarization selective absorption surfaces 2.
[0034] The inner side of the circular dichroism polarization selective absorption surface 2 is designed with three sections of circular arc-shaped metal branches that are not directly connected, which are respectively called the first circular arc-shaped metal branch, the second circular arc-shaped metal branch and the third circular arc-shaped metal branch. The first circular arc-shaped metal branch and the third circular arc-shaped metal branch are relatively spaced apart and together form a quasi-circular whole. The outer side of the circular dichroism polarization selective absorption surface 2 is attached with a metal copper reflector.
[0035] A resistor 3 is loaded between the first arc-shaped metal branch and the second arc-shaped metal branch, and the open end of the second arc-shaped metal branch points to the center of the circular whole.
[0036] The material of the external conformal frame 1 is FR4, with a thickness of 6 mm, a relative dielectric constant of 4.3, and a loss tangent value of 0.025.
[0037] Four metal strips 7 of equal distance and size are designed on the lower surface of the upper dielectric substrate 6 .
[0038] The Al2O3 dielectric resonator 8 is made of 99% pure aluminum oxide, has a relative dielectric constant of 9.5, a loss tangent of 0.003, a thickness of 6.35 mm, and is in the shape of a rectangle with notches at the four corners.
[0039] The upper surface of the lower dielectric substrate 10 is a metal ground 9 engraved with feeding cross slots of equal width and unequal length, and the lower layer is engraved with feeding microstrip lines 11.
[0040] Example:
[0041] The present embodiment provides a circularly polarized antenna with broadband axial ratio beam broadening, which can achieve beam bandwidth broadening in the entire frequency band, including an external conformal frame 1, an internal circularly polarized antenna, a circular dichroism polarization selective absorption surface 2 is designed on the conformal frame, and an upper frame metal boundary 4 and a lower frame metal boundary 5, the internal circularly polarized antenna includes an upper dielectric substrate 6, an Al2O3 dielectric resonator 8, and a lower dielectric substrate 10 from top to bottom, and the external conformal frame 1 and the metal ground 9 of the internal circularly polarized antenna are on the same horizontal plane. The present invention can achieve axial ratio beam bandwidth broadening in the entire frequency band and significantly improve the gain by arranging a circular dichroism selective absorption surface 2 on the external conformal frame 1 of the antenna to differentially absorb left-handed and right-handed circular polarizations, regulate the external electric field, and optimize the absorption effect through conformal design.
[0042] like Figure 1As shown, the external conformal frame 1 is a rectangular frame with a notch, which can be regarded as a rectangular parallelepiped with a length, width and height of 44mm×6mm×14mm protruding toward the internal circular polarization antenna and two rectangular parallelepipeds with a length, width and height of 44.5mm×6mm×14mm protruding outwards, overlapped by 4.5mm and bonded, and then rotated into a frame, with the middle area being hollow, and the internal circular polarization antenna is placed at the center of the external conformal frame 1. The material of the external conformal frame 1 is a 6mm thick FR4 dielectric substrate, whose relative dielectric constant is 4.3 and loss tangent is 0.025. According to the unit size of the circular dichroic polarization selective absorption surface 2 and the length of the frame, three circular dichroic polarization selective absorption surfaces 2 are evenly distributed on the inner side of each rectangular parallelepiped protruding toward the internal circular polarization antenna, and two circular dichroic polarization selective absorption surfaces 2 are evenly distributed on the inner side surfaces of the two rectangular parallelepipeds protruding outwards to ensure the absorption effect. For the entire outer frame, an upper frame metal border 4 and a lower frame metal border 5 are printed on the upper and lower surfaces of the outer conformal frame 1 respectively.
[0043] Internal circularly polarized antenna, such as Figure 1 and Figure 2 As shown, the metal strip 7 is on the lower surface of the upper dielectric substrate 6 and is placed on the Al2O3 dielectric resonator 8. The metal ground 9 is arranged on the top surface of the lower dielectric substrate 10. The Al2O3 dielectric resonator 8 is arranged on the metal ground 9. The feeding microstrip line 11 is on the lower surface of the lower dielectric substrate 10. The center of the metal ground 9 is engraved with equal-width 90° intersecting gaps. The signal is fed through the impedance matching feeding microstrip line, and the energy is coupled to the Al2O3 dielectric resonator 8 by the 90° intersecting gaps of the metal ground 9. After being regulated by the metal strip 7, circularly polarized electromagnetic waves are radiated to the frame. The upper dielectric substrate 6 and the lower dielectric substrate 10 are both made of Rogers 5880 plates, and the relative dielectric constant of the plates is 2.2, the loss tangent value is 0.0009, and the thickness is 0.762 mm.
[0044] Circular dichroism polarization selective absorption surface 2, such as Figure 3 and Figure 4As shown, three sections of indirect connected arc-shaped metal branches are distributed on the inner surface of the FR4 dielectric substrate, which are called the first arc-shaped metal branch, the second arc-shaped metal branch and the third arc-shaped metal branch in sequence. The first arc-shaped metal branch and the third arc-shaped metal branch are arranged with relative intervals to form a quasi-circular whole. A metal copper reflector is attached to the outer side of the circular dichroism polarization selective absorption surface 2. The inner diameter of the quasi-circular whole is r1 and the outer diameter is r2. The width of the three arc-shaped metal branches is 0.5mm. The opening angle of the third arc-shaped metal branch is θ1, the opening angle of the first arc-shaped metal branch is θ2, and the opening angle of the second arc-shaped metal branch is θ3. The first arc-shaped metal branch with an opening angle of θ2 and the second arc-shaped metal branch with an opening angle of θ3 are connected through a 100Ω resistor 3 of model 0402. The length, width and height of the resistor 3 are 1mm×0.5mm×0.3mm. The outer surface of the FR4 dielectric substrate is a metal reflector of the circular dichroism polarization selective absorption surface 2.
[0045] The three arc-shaped metal branches on the circular dichroism polarization selective absorption surface 2 and the metal reflector, the upper frame metal boundary 4, the lower frame metal boundary 5, the metal strip 7, the metal ground 9, and the feeding microstrip line 11, as shown in FIG. Figure 1-4 As shown, they are all made of copper sheets with a thickness of 0.035 mm.
[0046] The specific structural parameters of a broadband axial ratio beam broadening circularly polarized antenna proposed by the present invention are shown in Table 1, wherein l1, l5, and l6 are the length dimensions of the external conformal frame 1, w1, w4, and w5 are the width dimensions of the external conformal frame 1, l2 is the length and width dimensions of the metal ground 9 and the lower dielectric substrate 10, l4 and w2 are the length and width dimensions of the upper dielectric substrate 6, l3, l4 and w2, w3 are the overall dimensions of the dielectric resonator 8, l7 and h1 are the length, width and height dimensions of the circular dichroism polarization selective absorption surface 2, θ1, θ2, θ3 are the opening angles of the three arc-shaped metal branches on the circular dichroism polarization selective absorption surface 2, r1 and r2 are the inner and outer diameters of the arc-shaped metal branches, ls1, ls2, and ws1 are the length and width dimensions of the central cross gap of the metal ground 9, lf1, ws2 and lf2, ws3 are the length and width dimensions of the two microstrip lines that constitute the feeding microstrip line 11, respectively.
[0047] Table 1 Specific structural parameters of a broadband axial ratio beam broadening circularly polarized antenna
[0048] parameter <![CDATA[l1]]> <![CDATA[l2]]> <![CDATA[l3]]> <![CDATA[l4]]> <![CDATA[l5]]> <![CDATA[l6]]> Value(mm) 124 60 18 10.6 44 35 parameter <![CDATA[l7]]> <![CDATA[w1]]> <![CDATA[w2]]> <![CDATA[w3]]> <![CDATA[w4]]> <![CDATA[w5]]> Value(mm) 7 124 10 18 16 6 parameter <![CDATA[h1]]> <![CDATA[θ1]]> <![CDATA[θ2]]> <![CDATA[θ3]]> <![CDATA[r1]]> <![CDATA[r2]]> Value(mm) 6 138 160 30 5.5 6 parameter <![CDATA[ws2]]> <![CDATA[ws3]]> <![CDATA[lf2]]> <![CDATA[ls1]]> <![CDATA[ls2]]> <![CDATA[ws1]]> Value(mm) 2.3 1.6 10 9.6 16.8 1
[0049] Figure 5It is a schematic diagram of the absorption curve of the circular dichroism polarization selective absorption surface of the circularly polarized antenna with broadband axial ratio beam broadening in this embodiment. It can be seen from the figure that within the frequency range of (4.2-5.6 GHz), the highest right-hand circular polarization absorption rate of the circular dichroism polarization selective absorption surface exceeds 98%, while the lowest left-hand circular polarization absorption rate is less than 10%, and the entire frequency band has effective differential absorption for right-hand circular polarization and left-hand circular polarization.
[0050] like Figures 6 to 8 As shown, the impedance bandwidth of the broadband axial ratio beam broadening circularly polarized antenna proposed by the present invention is 31.1% (4.27-5.84 GHz), the axial ratio bandwidth is 33.2% (4.09-5.72 GHz), and the peak gain in the passband range is 10 dBi.
[0051] like Figures 9 to 16 As shown, eight frequency points, namely 4.2 GHz, 4.4 GHz, 4.6 GHz, 4.8 GHz, 5.0 GHz, 5.2 GHz, 5.4 GHz and 5.6 GHz, were selected to observe the axial ratio beam width broadening of the xoz plane and yoz plane at each frequency point using the conformal frame antenna with circular dichroism polarization selective absorption surface. It can be seen that there are different angle broadenings compared with the metal frame. At 4.2 GHz, the 3dB axial ratio beam width in the xoz plane and yoz plane are broadened by 66.5% and 182% respectively; at 5.0 GHz, the 3dB axial ratio beam width in the xoz plane and yoz plane are broadened by 140.1% and 14.7% respectively; at 5.6 GHz, the 3dB axial ratio beam width in the xoz plane and yoz plane are broadened by 151.6% and 9% respectively.
[0052] like Fig.17 As shown, it can be seen that the radiation direction of the antenna of the present invention has good symmetry, and there is good isolation between left-handed and right-handed polarizations in the main radiation direction.
[0053] In summary, the present invention only uses common dielectric plates, common resistors and easily available ceramic dielectrics, and cleverly combines the circular dichroism selective absorption surface with the antenna frame, and adopts a rectangular frame with a notch, which is conformally designed with the antenna, thereby achieving effective selective absorption of left-hand circular polarization and right-hand circular polarization, significantly improving the signal gain and axial ratio beam width, and ultimately achieving beam bandwidth broadening for all frequency points within a wide frequency band, providing a feasible solution to achieve beam broadening within a wide bandwidth range.
Claims
1. A circularly polarized antenna with broadband axial ratio beam broadening, characterized in that: Able to achieve full-band beamwidth expansion, including: External conformal border (1), The inner circularly polarized antenna is located at the center of the outer conformal frame (1), A circular dichroism polarization selective absorption surface (2) designed on the outer conformal frame (1), An upper frame metal boundary (4) and a lower frame metal boundary (5) located on the upper and lower surfaces of the external conformal frame (1); The internal circularly polarized antenna comprises, from top to bottom, an upper dielectric substrate (6) with a metal strip (7), an Al2O3 dielectric resonator (8), and a lower dielectric substrate (10) with a feeding structure. The external conformal frame (1) and the metal ground (9) of the internal circular polarization antenna are on the same horizontal plane.
2. A broadband axial ratio beam broadening circularly polarized antenna according to claim 1, characterized in that: The external conformal frame (1) is a rectangular frame with inner notches in the middle of the four sides, three circular dichroism polarization selective absorption surfaces (2) are evenly distributed on the inner wall surface of the inner notch on each side, and two convex parts on both sides of the inner notch are each distributed with two circular dichroism polarization selective absorption surfaces (2).
3. A broadband axial ratio beam broadening circularly polarized antenna according to claim 2, characterized in that: The inner side of the circular dichroism polarization selective absorption surface (2) is designed with three sections of circular arc-shaped metal branches that are not directly connected, which are respectively called the first circular arc-shaped metal branch, the second circular arc-shaped metal branch and the third circular arc-shaped metal branch. The first circular arc-shaped metal branch and the third circular arc-shaped metal branch are arranged with relative intervals to form a circular whole. The outer side of the circular dichroism polarization selective absorption surface (2) is attached with a metal copper reflection plate.
4. A broadband axial ratio beam broadening circularly polarized antenna according to claim 3, characterized in that: A resistor (3) is loaded between the first arc-shaped metal branch and the second arc-shaped metal branch, and the open end of the second arc-shaped metal branch points to the center of the circular whole.
5. The broadband axial ratio beam broadening circularly polarized antenna according to claim 1, characterized in that: The material of the external conformal frame (1) is FR4, with a thickness of 6 mm, a relative dielectric constant of 4.3, and a loss tangent of 0.
025.
6. The broadband axial ratio beam broadening circularly polarized antenna according to claim 1, characterized in that: Four metal strips (7) of equal distance and size are designed on the lower surface of the upper dielectric substrate (6).
7. The broadband axial ratio beam broadening circularly polarized antenna according to claim 1, characterized in that: The Al2O3 dielectric resonator (8) is made of 99% pure aluminum oxide, has a relative dielectric constant of 9.5, a loss tangent of 0.003, a thickness of 6.35 mm, and is in the shape of a rectangle with notches at the four corners.
8. The broadband axial ratio beam broadening circularly polarized antenna according to claim 1, characterized in that: The upper surface of the lower dielectric substrate (10) is a metal ground (9) engraved with feeding cross gaps of equal width and unequal length, and the lower layer is engraved with feeding microstrip lines (11).