A dual-polarized dipole antenna based on odd mode and even mode fusion

Abstract

The application relates to the technical field of mobile communication, and discloses a dual-polarization dipole antenna based on odd mode and even mode fusion, which comprises a dielectric plate, a first dipole and a second dipole, the first dipole is printed on the upper surface of the dielectric plate, the second dipole is printed on the lower surface of the dielectric plate, and the first dipole is perpendicular to the second dipole. The application solves the problems that the existing dual-polarization dipole antenna cannot simultaneously meet the requirements of miniaturization and wide bandwidth.

Description

Technical Field

[0001] This invention relates to the field of mobile communication technology, specifically a dual-polarized dipole antenna based on the fusion of odd and even modes. Background Technology

[0002] The dipole antenna is one of the earliest, simplest, and most widely used antennas in radio communication. It consists of a pair of symmetrically placed conductors (also called "dipole arms"), with their ends connected to a feed line. The diameter of the dipole antenna arms is much smaller than the operating wavelength and the arm length. The arms can be a pair of symmetrical thin metal tubes or a pair of symmetrical microstrip lines, etc. A common dipole antenna has an arm length of half a wavelength (0.5λ, where λ is the free-space wavelength corresponding to the center frequency of the dipole's operating band). It can resonate in odd-mode, i.e., at frequencies corresponding to 0.5λ, 1.5λ, 2.5λ, etc., but it cannot resonate at frequencies corresponding to even-mode, such as 1λ, 2λ, 3λ. For information on odd and even modes of dipole antennas, please refer to the article “Bing Xiao, Hang Wong, Min Li, Bo Wang and KwanL.Yeung. Dipole Antenna with Both Odd and Even Modes Excited and Tuned[J].IEEE Transactions on Antennas and Propagation, 70(3):1643~1652, 2022”.

[0003] The bandwidth of a dipole is mainly determined by the thickness or width of its arms. Within a certain range, the thicker or wider the dipole arms, the greater the bandwidth. For example, the literature “Zengdi Bao, Zaiping Nie and Xianzheng Zong. A Novel Broadband Dual-Polarization Antenna Utilizing Strong Mutual Coupling[J].IEEE Transactions on Antennas and Propagation,62(1):450~454,2014” proposes a dual-polarized dipole antenna. Each dipole arm is a square ring with a side length of 23.8mm (0.18λ). (Due to the edge effect of the dipole, the length of a single dipole arm is less than 0.25λ, and the length of the entire dipole is less than 0.5λ). The square ring structure is equivalent to increasing the radiation area of ​​the dipole, which increases the antenna bandwidth. Then, the two dipoles with square ring arms are placed crosswise. By utilizing the coupling between the two adjacent dipole arms, the antenna bandwidth is further broadened. Finally, the antenna can cover the 1.7-2.7GHz frequency band. For example, the invention patent with application number 201580002401.3, "A Multi-Frequency Communication Antenna and Base Station", also has a main radiator composed of two intersecting dipoles. The arm of each dipole is a square ring structure. Although the specific dimensions of the antenna are not given, according to the basic theory of half-wave dipoles, the side length of each radiator arm of the antenna is about 0.15 to 0.25λ. Combining geometric knowledge, the length of a single dipole can be estimated to be about 0.42 to 0.79λ, and the width of a single dipole is about 0.21 to 0.35λ.

[0004] There is an urgent need for a miniaturized dual-polarized dipole antenna with a wide bandwidth. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a dual-polarized dipole antenna based on the fusion of odd and even modes, which solves the problems of existing technologies that make it difficult to achieve a dual-polarized dipole antenna that is both miniaturized and has a wide bandwidth.

[0006] The technical solution adopted by the present invention to solve the above problems is:

[0007] A dual-polarized dipole antenna based on odd-mode and even-mode fusion includes a dielectric substrate, a first dipole, and a second dipole. The first dipole is printed on the upper surface of the dielectric substrate, and the second dipole is printed on the lower surface of the dielectric substrate. The first dipole and the second dipole are perpendicular to each other.

[0008] As a preferred technical solution, the first dipole includes a first feed point, a first radiating arm connected to one end of the first feed point, and a second radiating arm connected to the other end of the first feed point; the second dipole includes a second feed point, a third radiating arm connected to one end of the second feed point, and a fourth radiating arm connected to the other end of the second feed point.

[0009] As a preferred technical solution, the first radiating arm includes a first narrow rectangular microstrip and a first wide rectangular microstrip; the second radiating arm includes a second narrow rectangular microstrip and a second wide rectangular microstrip; the first wide rectangular microstrip, the first narrow rectangular microstrip, the first feed point, the second narrow rectangular microstrip, and the second wide rectangular microstrip are connected in sequence; the third radiating arm includes a third narrow rectangular microstrip and a third wide rectangular microstrip; and the fourth radiating arm includes a fourth narrow rectangular microstrip and a fourth wide rectangular microstrip; the third wide rectangular microstrip, the third narrow rectangular microstrip, the second feed point, the fourth narrow rectangular microstrip, and the fourth wide rectangular microstrip are connected in sequence.

[0010] As a preferred technical solution, it further includes a first rectangular coupling strip, a first wide rectangular microstrip, a first narrow rectangular microstrip, a first feed point, a second narrow rectangular microstrip, and a second wide rectangular microstrip forming a rectangular slot, with the first rectangular coupling strip disposed within the rectangular slot, and the first rectangular coupling strip, the first radiating arm, and the second radiating arm forming a first U-shaped slot; it also includes a second rectangular coupling strip, a third wide rectangular microstrip, a third narrow rectangular microstrip, a second feed point, a fourth narrow rectangular microstrip, and a fourth wide rectangular microstrip forming another rectangular slot, with the second rectangular coupling strip disposed within the rectangular slot, and the second rectangular coupling strip, the third radiating arm, and the fourth radiating arm forming a second U-shaped slot.

[0011] As a preferred technical solution, the width range of both the first U-shaped gap and the second U-shaped gap is 0.1mm to 2mm.

[0012] As a preferred technical solution, the lengths of the first dipole and the second dipole are both in the range of 52mm to 67mm, and the widths of the first dipole and the second dipole are both in the range of 6mm to 10mm.

[0013] As a preferred technical solution, the distance between the first feed point and the geometric center of the first dipole is 3mm to 13mm, and the distance between the second feed point and the geometric center of the second dipole is 3mm to 13mm.

[0014] As a preferred technical solution, the dielectric constant of the dielectric substrate is 1 to 20.

[0015] As a preferred technical solution, the thickness of the dielectric substrate is 0.5mm to 3mm.

[0016] As a preferred technical solution, the dielectric substrate is an FR-4 dielectric substrate.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] This invention shifts the feed point of a traditional half-wavelength dipole at its center, exciting an even-mode (1λ) and generating a resonant point operating in even-mode. This resonant point, after forming a dual-polarized antenna, shifts to lower frequencies, merging with the dipole's own odd-mode (0.5λ), thus expanding the antenna bandwidth. By etching concave slots on the dipole arms and setting coupling strips within these slots, the induced current on the dipole arms corresponding to the non-excited ports is weakened, improving the port isolation of the dual-polarized dipole near the even-mode resonant point. The aforementioned dual-polarized antenna can cover 1.7-2.7 GHz, maintaining an in-band isolation of over 31.7 dB, with a single dipole length of 0.43λ and a width of only 0.056λ. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of the first dipole of the present invention;

[0021] Figure 3 This is a schematic diagram of the structure of the second dipole of the present invention;

[0022] Figure 4 This is a schematic diagram illustrating the technological evolution of an embodiment of the present invention;

[0023] Figure 5 yes Figure 4 S-parameter curves corresponding to antennas 1 and 2;

[0024] Figure 6 yes Figure 4 S-parameter curves corresponding to antennas 3-4 in the middle section;

[0025] Figure 7 This is the orientation pattern of the invention in the XOZ plane;

[0026] Figure 8 This is the orientation pattern of the present invention in the YOZ plane.

[0027] The labels and their corresponding names in the attached figures are as follows: 1-Dielectric plate, 2-First dipole, 21-First radiating arm, 22-Second radiating arm, 23-First rectangular coupling bar, 24-First U-shaped slot, 25-First feed point, 3-Second dipole, 31-Third radiating arm, 32-Fourth radiating arm, 33-Second rectangular coupling bar, 34-Second U-shaped slot, 35-Second feed point. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0029] The technical solutions in the embodiments of the present invention are clearly and completely described in the following description. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] In the description of the embodiments of the present invention, it should be noted that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is conventionally placed during use, or the orientation or positional relationship in which those skilled in the art conventionally understand it during use. This is only for the convenience of describing the present invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. Furthermore, the terms "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] Example 1

[0032] like Figures 1 to 8 As shown, the purpose of this invention is to propose a small broadband dual-polarized dipole antenna based on the fusion of odd and even modes. First, the even mode of the dipole is excited by shifting the dipole feed point. Second, it is rotated 90 degrees and combined with the original offset dipole to form a dual-polarized antenna. The resonant point corresponding to the even mode moves to a lower frequency. Finally, grooves are etched at appropriate positions on the dipole arms, and coupling strips are set in the grooves to weaken the isolation between the ports of the dual-polarized dipole.

[0033] Small broadband dual-polarized dipole antenna based on odd-mode and even-mode fusion, such as Figure 1 As shown, the device includes a dielectric substrate 1, a first dipole 2, and a second dipole 3. The first dipole 2 is printed on the upper surface of the dielectric substrate 1, and the second dipole 3 is printed on the lower surface of the dielectric substrate 1. The first dipole 2 and the second dipole 3 are spatially perpendicular to each other. In this embodiment, the dielectric substrate 1 is made of FR4 substrate with a relative permittivity of 4.4 and a thickness of 1.6 mm. The permittivity and thickness of the dielectric substrate 1 can be selected according to actual needs.

[0034] The first dipole 2 includes a first radiating arm 21, a second radiating arm 22, a first rectangular coupling strip 23, a first U-shaped gap 24, and a first feed point 25. The first feed point 25 is a feed port set in the simulation software, which simulates the coaxial cable feed structure. In the actual manufacturing process, the inner core of the coaxial cable is connected to the first radiating arm 21, and the outer core of the coaxial cable is connected to the second radiating arm 22. The first radiating arm 21 consists of a narrow rectangular microstrip and a wide rectangular microstrip. The second radiating arm 22 also consists of a narrow rectangular microstrip and a wide rectangular microstrip. The narrow rectangular microstrip of the first radiating arm 21 and the narrow rectangular microstrip of the second radiating arm 22, together with the wide rectangular microstrip of the first radiating arm 21 and the wide rectangular microstrip of the second radiating arm 22, form a rectangular region. In the rectangular region, the first rectangular coupling strip 23 is set, and the first rectangular coupling strip 23 forms the first U-shaped gap 24 between the first radiating arm 21 and the second radiating arm 22.

[0035] The second dipole 3 includes a third radiating arm 31, a fourth radiating arm 32, a second rectangular coupling bar 33, a second U-shaped slot 34, and a second feed point 35. Its structural dimensions are the same as those of the first dipole 2.

[0036] The length of the first dipole 2 and the second dipole 3 is 58 mm (0.43λ), and the width is 7.5 mm (0.056λ); the width of the first U-shaped slot 24 and the second U-shaped slot 34 is 0.3 mm, and their size affects not only the antenna reflection coefficient (|S) 11 |) has an impact, and also affects the isolation between ports (|S) 21 |) This has an impact. Researchers can adjust the above structure and dimensions according to the indicator requirements.

[0037] To explain the working principle of the antenna, Figure 4 A schematic diagram of the technical evolution of the antenna is given. Antenna 1 is a center-fed single-polarized dipole, antenna 2 is a single-polarized dipole with an offset feed point, antenna 3 is obtained by adding a dipole rotated 90 degrees on the back of the dielectric substrate based on antenna 2, and antenna 4 is the one in this embodiment. Figure 5 Given Figure 4 |S corresponding to antennas 1-2 11 |Curve, by Figure 5 It can be seen that antenna 1 is in |S 11 When | < -10dB, there is only one resonant point at 1.8GHz, which corresponds to the odd mode (0.5λ) of the dipole. At this time, the even mode (1λ) of the dipole cannot be excited. By shifting the feed point, antenna 2 not only resonates at 1.8GHz, but also at a position twice the odd mode frequency, i.e., 3.6GHz. At this time, the odd mode and even mode of the dipole are excited at the same time. Figure 6 Given Figure 4 |S| corresponding to antennas 3-4 11 |、|S 21 As shown in the curve, after forming the dual-polarized antenna 3 based on antenna 2, the frequency corresponding to the even-mode shifts to a lower frequency band, around 2.4 GHz, due to the coupling between the two polarized antennas. However, the port isolation between the two dipoles is very poor at this point, especially at 2.4 GHz, where the port isolation is only 7 dB. This indicates that although coupling can shift the resonant point corresponding to the even-mode to a lower frequency, the generated coupling current cannot be canceled at the unexcited port, resulting in low port isolation. Therefore, we engrave concave grooves on the dipole arms and set the first rectangular coupling strip 23 and the second rectangular coupling strip 33 in the grooves to improve the isolation between the ports of the dual-polarized dipoles. Figure 6 As shown, antenna 4 can not only cover the 1.7 to 2.7 GHz frequency band, but also improve the isolation between the first feed point 25 and the second feed point 35 to more than 31.7 dB.

[0038] Figure 7 and 8 The radiation patterns of the antenna in the XOZ and YOZ planes are given respectively. Figure 7 , Figure 8 As can be seen, the antenna can radiate omnidirectionally in the YOZ plane, and its radiation pattern in the XOZ plane is similar to the figure "8", which conforms to the characteristics of a dipole radiation pattern, indicating good radiation performance.

[0039] The above embodiment has an omnidirectional YOZ plane radiation pattern. Researchers can also place a metal reflective ground at a distance of about a quarter wavelength from the antenna to form directional radiation.

[0040] The beneficial effects of this invention are as follows: A small broadband dual-polarized dipole antenna based on odd-mode and even-mode fusion is provided. The feed point of a traditional half-wavelength dipole, located at its center, is shifted to excite an even-mode (1λ) and generate a resonant point operating in even-mode. This resonant point, after forming the dual-polarized antenna, shifts to lower frequencies and merges with the dipole's own odd-mode (0.5λ), thus expanding the antenna bandwidth. By etching concave slots on the dipole arms and setting coupling strips within the slots, the induced current on the dipole arms corresponding to the non-excited ports is weakened, improving the port isolation of the dual-polarized dipole near the even-mode resonant point. This dual-polarized antenna can cover 1.7-2.7 GHz, maintaining an in-band isolation of over 31.7 dB, with a single dipole length of 0.43λ and a width of only 0.056λ.

[0041] As described above, the present invention can be implemented well.

[0042] All features disclosed in all embodiments of this specification, or steps in all methods or processes implied in the disclosure, may be combined and / or extended or replaced in any way, except for mutually exclusive features and / or steps.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A dual-polarized dipole antenna based on odd-mode and even-mode fusion, characterized in that, It includes a dielectric substrate (1), a first dipole (2), and a second dipole (3). The first dipole (2) is printed on the upper surface of the dielectric substrate (1), and the second dipole (3) is printed on the lower surface of the dielectric substrate (1). The first dipole (2) and the second dipole (3) are perpendicular to each other. The second dipole (3) is obtained by rotating the first dipole (2) by 90 degrees. The first dipole (2) includes a first feed point (25), a first radiating arm (21) connected to one end of the first feed point (25), and a second radiating arm (22) connected to the other end of the first feed point (25); the second dipole (3) includes a second feed point (35), a third radiating arm (31) connected to one end of the second feed point (35), and a fourth radiating arm (32) connected to the other end of the second feed point (35); The first radiating arm (21) includes a first narrow rectangular microstrip (211) and a first wide rectangular microstrip (212); the second radiating arm (22) includes a second narrow rectangular microstrip (221) and a second wide rectangular microstrip (222); the first wide rectangular microstrip (212), the first narrow rectangular microstrip (211), the first feed point (25), the second narrow rectangular microstrip (221), and the second wide rectangular microstrip (222) are connected in sequence; the third radiating arm (31) includes a third narrow rectangular microstrip (311) and a third wide rectangular microstrip (312); the fourth radiating arm (32) includes a fourth narrow rectangular microstrip (321) and a fourth wide rectangular microstrip (322); the third wide rectangular microstrip (312), the third narrow rectangular microstrip (311), the second feed point (35), the fourth narrow rectangular microstrip (321), and the fourth wide rectangular microstrip (322) are connected in sequence; It also includes a first rectangular coupling strip (23), a first wide rectangular microstrip (212), a first narrow rectangular microstrip (211), a first feed point (25), a second narrow rectangular microstrip (221), and a second wide rectangular microstrip (222) forming a rectangular slot, with the first rectangular coupling strip (23) located within the rectangular slot. The first rectangular coupling strip (23), the first radiating arm (21), and the second radiating arm (22) together form a first U-shaped slot (24); it also includes a second rectangular coupling strip (33). The third wide rectangular microstrip (312), the third narrow rectangular microstrip (311), the second feed point (35), the fourth narrow rectangular microstrip (321), and the fourth wide rectangular microstrip (322) enclose another rectangular slot. The second rectangular coupling strip (33) is located in the rectangular slot. The second rectangular coupling strip (33), the third radiating arm (31), and the fourth radiating arm (32) enclose a second U-shaped slot (34). The distance between the first feed point (25) and the geometric center of the first dipole (2) is 3 mm to 13 mm.

2. The dual-polarized dipole antenna based on odd-mode and even-mode fusion according to claim 1, characterized in that, The widths of the first U-shaped gap (24) and the second U-shaped gap (34) are both in the range of 0.1 mm to 2 mm.

3. The dual-polarized dipole antenna based on odd-mode and even-mode fusion according to claim 1, characterized in that, The lengths of the first dipole (2) and the second dipole (3) are both 52 mm to 67 mm, and the widths of the first dipole (2) and the second dipole (3) are both 6 mm to 10 mm.

4. A dual-polarized dipole antenna based on odd-mode and even-mode fusion according to claim 1, characterized in that, The distance between the second feed point (35) and the geometric center of the second dipole (3) is 3 mm to 13 mm.

5. A dual-polarized dipole antenna based on odd-mode and even-mode fusion according to any one of claims 1 to 3, characterized in that, The dielectric constant of the dielectric substrate (1) is 1~20.

6. A dual-polarized dipole antenna based on odd-mode and even-mode fusion according to claim 4, characterized in that, The thickness of the dielectric plate (1) is 0.5 mm to 3 mm.

7. A dual-polarized dipole antenna based on odd-mode and even-mode fusion according to claim 6, characterized in that, The dielectric substrate (1) is an FR-4 dielectric substrate.

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