A folded dipole base station antenna with very low profile

Abstract

The application provides a kind of folded dipole base station antenna with extremely low profile, belongs to mobile communication technical field, is related to the structure of base station antenna, solves the various limitations problems existing in the structure of existing base station antenna;Including main radiator, secondary radiator, dielectric plate and metal ground plane;Main radiator is arranged on the upper surface of dielectric plate, secondary radiator is arranged on the lower surface of dielectric plate, and metal ground plane is arranged below dielectric plate;Feed port is arranged between main radiator and secondary radiator, feed port passes through dielectric plate, and is connected with main radiator and secondary radiator respectively, and feed port is used to provide feed for main radiator and secondary radiator in differential feed mode;The application provides feed in differential feed mode, so that the base station antenna has good radiation performance, and also has the advantages of extremely low profile, high gain and good directivity, reduces the antenna volume, realizes the miniaturization of antenna, reduces wind resistance and reduces the cost of antenna installation and future maintenance.

Description

Technical Field

[0001] This invention belongs to the field of mobile communication technology and relates to the structure of base station antennas, specifically a folded dipole base station antenna with an extremely low profile. Background Technology

[0002] With the rapid development of wireless communication technology, 5G communication systems have been widely used. Due to the significant increase in 5G communication frequencies, the coverage area of ​​a single base station antenna has decreased, leading to a greater demand for base station antennas and a need for denser deployment, resulting in a scarcity of space resources. Therefore, reducing the cross-section of base station antennas and achieving miniaturization is an urgent problem to be solved in current mobile communication technology.

[0003] The current telecommunications industry is highly competitive. Major mobile operators require base station antennas to be both high-performance and low-cost. Half-wave dipoles are widely used in base station antennas due to their simple fabrication and easy assembly, along with good directional radiation and impedance matching capabilities. Since base station antennas need to be erected at a height, wind resistance becomes a major consideration for installation and maintenance costs. Half-wave dipole base station antennas require a lower profile to reduce wind resistance after being erected, significantly reducing installation and future maintenance costs. Therefore, designing high-gain, wide-bandwidth, and low-profile high-performance base station antennas has become a hot and challenging research topic in the antenna field.

[0004] Existing technologies include: a magnetic dipole antenna that achieves a profile height of 0.07λ by forming a circulating current on the surface of a metal patch while maintaining a constant circulating current length; however, its gain and antenna pattern front-to-back ratio require further improvement. Another high-gain patch antenna consists of four radiating elements. To extend the current propagation path, a fan-shaped slot is cut out of each radiating element, and four feed holes are electrically connected to the microstrip feed line via feed pillars; however, its profile height still needs further reduction. A low-profile base station antenna reduces the antenna profile by folding a vertical patch and a metal ground plane; its directivity still needs further improvement. It is evident that existing technologies for base station antenna design consistently have various limitations and shortcomings. Designing a comprehensive, high-performance base station antenna remains a challenging problem in the field of mobile communications. Summary of the Invention

[0005] This invention provides a folded dipole base station antenna with extremely low profile, high gain, and good directivity by using a differential feeding method. It operates in the 5G n78 frequency band. While ensuring good radiation performance, it effectively reduces the antenna profile, thus solving the limitations of the prior art.

[0006] The present invention employs the following technical solutions to achieve its objective:

[0007] A folded dipole base station antenna with an extremely low profile includes a main radiator, a secondary radiator, a dielectric substrate, and a metal ground plane. The main radiator is disposed on the upper surface of the dielectric substrate, the secondary radiator is disposed on the lower surface of the dielectric substrate, and the metal ground plane is disposed below the dielectric substrate. A feed port is provided between the main radiator and the secondary radiator, the feed port passing through the dielectric substrate and connecting the main radiator and the secondary radiator respectively, and the feed port is used to provide differential feed to the main radiator and the secondary radiator.

[0008] Furthermore, the main radiator includes a first microstrip line and a second microstrip line, which are symmetrically arranged on both sides of the central axis on the upper surface of the dielectric substrate.

[0009] Specifically, the first microstrip line and the second microstrip line have the same structure and size.

[0010] Furthermore, the secondary radiator includes a third microstrip line and a fourth microstrip line, which are symmetrically arranged on both sides of the central axis of the lower surface of the dielectric substrate.

[0011] Specifically, the third microstrip line and the fourth microstrip line have the same structure and size.

[0012] Furthermore, the power supply port includes a first end power supply port and a second end power supply port. The first end power supply port is located at the end of the first microstrip line near the end of the second microstrip line, and the second end power supply port is located at the end of the second microstrip line near the end of the first microstrip line. The first end power supply port is also connected to the end of the third microstrip line near the end of the fourth microstrip line, and the second end power supply port is also connected to the end of the fourth microstrip line near the end of the third microstrip line.

[0013] Specifically, the first end feed port is used to provide a first excitation signal to the first microstrip line and the third microstrip line for power supply, and the second end feed port is used to provide a second excitation signal to the second microstrip line and the fourth microstrip line for power supply; the first excitation signal and the second excitation signal have equal amplitudes and are 180 degrees out of phase.

[0014] Specifically, the dielectric substrate is an FR-4 dielectric substrate with a dielectric constant of 4.4 and a thickness of 0.8 mm.

[0015] Specifically, the distance between the metal ground plane and the lower surface of the dielectric plate is 6 mm.

[0016] Specifically, the first, second, third, and fourth microstrip lines are all rectangular patch structures. The first and second microstrip lines are 32.5 mm long and 2 mm wide; the third and fourth microstrip lines are 22.5 mm long and 8 mm wide; the dielectric substrate is 100 mm long and 30 mm wide; and the metal ground plane has a side length of 300 mm.

[0017] In summary, due to the adoption of this technical solution, the beneficial effects of this invention are as follows:

[0018] Compared with traditional base station antenna structures, this invention connects the feed line directly to the antenna radiator and uses microstrip direct feeding to feed the antenna, thereby reducing losses and achieving a peak antenna simulation gain of 9.7 dBi.

[0019] This invention employs a folded dipole antenna, which enables the base station antenna to have a good front-to-back ratio while reducing the cost of the antenna.

[0020] This invention employs a differential feeding method with identical amplitude, 180-degree phase difference, and simultaneous excitation of two feed ports. This reduces the profile of the dipole base station antenna, lowering the distance between the dielectric substrate and the metal ground plane to 6mm. The antenna operates in the 5G n78 band (3400-3600MHz), which is only 0.07 times the free space wavelength corresponding to the center frequency. The extremely low profile enables antenna miniaturization and effectively reduces wind resistance after elevation, significantly reducing the costs of antenna installation and future maintenance.

[0021] Therefore, compared with traditional technologies, this invention effectively reduces the size of the antenna, achieves antenna miniaturization, enables the antenna to operate stably in the corresponding frequency band, and has high gain and good directivity, thereby solving various limitations in the traditional base station antenna structure. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the dipole base station antenna of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of a traditional dipole base station antenna;

[0024] Figure 3 The S-parameter diagram of the dipole base station antenna of the present invention is shown below;

[0025] Figure 4 This is a simulated radiation pattern of the YOZ plane of the dipole base station antenna of the present invention;

[0026] Figure 5This is a gain curve diagram of the dipole base station antenna of the present invention;

[0027] Figure 6 The S-parameter diagram is for a traditional dipole base station antenna.

[0028] Figure 7 The simulated radiation pattern of the YOZ plane of a traditional dipole base station antenna;

[0029] Figure 8 This is a gain curve diagram for a traditional dipole base station antenna.

[0030] The meanings of the markings in the attached diagram are as follows:

[0031] 11-First microstrip line, 12-Second microstrip line, 21-Third microstrip line, 22-Fourth microstrip line, 31-First end feed port, 32-Second end feed port, 4-Dielectric substrate, 5-Metallic ground plane, 61-First microstrip line of conventional antenna, 62-Second microstrip line of conventional antenna, 7-Dielectric substrate of conventional antenna, 8-Feed port of conventional antenna, 9-Metallic ground plane of conventional antenna. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0034] This embodiment provides a detailed description of the folded dipole base station antenna with an extremely low profile of the present invention by comparing it with a conventional dipole base station antenna.

[0035] Figure 2The structure of a conventional dipole base station antenna is shown, including a radiator, a dielectric substrate 7, and a metal ground plane 9. The radiator is composed of a first microstrip line 61 and a second microstrip line 62, both with identical structures and dimensions, and symmetrically distributed about the perpendicular bisector of the dielectric substrate 7 on its upper surface. The lengths of the first and second microstrip lines 61 and 62 are designed according to their resonant frequency requirements. When the conventional dipole base station antenna operates in the 3.4 GHz to 3.6 GHz frequency band with a center frequency of 3.5 GHz, the resonant frequency can be adjusted by changing the lengths of the first and second microstrip lines 61 and 62. The dielectric constant and thickness of the dielectric substrate 7 are then incorporated into the design. Using conventional calculation formulas, the waveguide wavelength corresponding to a center frequency of 3.5 GHz is calculated to be 95.2 mm. The lengths of the first microstrip line 61 and the second microstrip line 62 of the conventional antenna are both designed to be 10.5 mm, approximately 0.11 times the waveguide wavelength. The metal ground plane 9 of the conventional antenna is located 21 mm below the dielectric substrate 7 of the conventional antenna, approximately 0.25 times the free space wavelength corresponding to the center frequency. Since the operating frequency band of the conventional base station antenna in this example is 3.4 GHz to 3.6 GHz, and the center frequency is 3.5 GHz, the calculated wavelength is 85.7 mm. In this embodiment, the feed port 8 of the conventional antenna is distributed between the first microstrip line 61 and the second microstrip line 62 of the conventional antenna, with a length of 8 mm and a width of 2 mm. The excitation signal is generated by the feed network.

[0036] Next, the structure of the folded dipole base station antenna with an extremely low profile in the technical solution of this invention will be described, such as... Figure 1 As shown, a folded dipole base station antenna with an extremely low profile includes a main radiator, a secondary radiator, a dielectric substrate 4, and a metal ground plane 5; the main radiator is disposed on the upper surface of the dielectric substrate 4, and the secondary radiator is disposed on the lower surface of the dielectric substrate 4. Figure 1 To facilitate viewing of the secondary radiator, the dielectric plate 4 is made transparent (the actual secondary radiator is located on the lower surface of the dielectric plate 4 and is obscured by the dielectric plate 4). The metal ground plane 5 is located below the dielectric plate 4. A feed port is provided between the main radiator and the secondary radiator. The feed port passes through the dielectric plate 4 and is connected to the main radiator and the secondary radiator respectively. The feed port is used to provide power to the main radiator and the secondary radiator in a differential feeding manner.

[0037] The main radiator includes a first microstrip line 11 and a second microstrip line 12, which are symmetrically arranged on both sides of the central axis on the upper surface of the dielectric substrate 4; the first microstrip line 11 and the second microstrip line 12 have the same structure and size.

[0038] The secondary radiator includes a third microstrip line 21 and a fourth microstrip line 22, which are symmetrically arranged on both sides of the central axis on the lower surface of the dielectric substrate 4; the third microstrip line 21 and the fourth microstrip line 22 have the same structure and size.

[0039] The power supply ports include a first end power supply port 31 and a second end power supply port 32. The first end power supply port 31 is located at the end of the first microstrip line 11 near the end of the second microstrip line 12, and the second end power supply port 32 is located at the end of the second microstrip line 12 near the end of the first microstrip line 11. The first end power supply port 31 is also connected to the end of the third microstrip line 21 near the end of the fourth microstrip line 22, and the second end power supply port 32 is also connected to the end of the fourth microstrip line 22 near the end of the third microstrip line 21.

[0040] In this embodiment, the first end feed port 31 is used to provide a first excitation signal to the first microstrip line 11 and the third microstrip line 12 for power supply, and the second end feed port 32 is used to provide a second excitation signal to the second microstrip line 21 and the fourth microstrip line 22 for power supply; the amplitudes of the first excitation signal and the second excitation signal are equal, and the phase difference is 180 degrees.

[0041] In this embodiment, the center frequency of the base station antenna is still 3.5 GHz, and the distance between the metal ground plane 5 and the lower surface of the dielectric substrate 4 is 6 mm, which is about 0.07 times the free space wavelength corresponding to the center frequency. The operating frequency band of the base station antenna in this embodiment is 3.4 GHz to 3.6 GHz. According to conventional calculations in the art, the wavelength corresponding to the center frequency of 3.5 GHz is 85.7 mm.

[0042] In this embodiment, the dielectric substrate 4 is an FR-4 dielectric substrate with a dielectric constant of 4.4 and a thickness of 0.8 mm. Its length is 100 mm and its width is 30 mm. The dielectric constant, length, width and thickness of the dielectric substrate 4 can be selected according to actual needs in actual application.

[0043] The side lengths of the main radiators, the first microstrip line 11 and the second microstrip line 12, and the secondary radiators, the third microstrip line 21 and the fourth microstrip line 22, are designed according to the requirements of their resonant frequency. The base station antenna operates in the frequency band of 3.4 GHz to 3.6 GHz, with a center frequency of 3.5 GHz. The side lengths of the main radiators, the third microstrip line 21 and the fourth microstrip line 22, are related to the resonant frequency. By adjusting the side lengths of the main radiators, the resonant frequency of the base station antenna can be adjusted.

[0044] Substituting the dielectric constant 4.4 and thickness 0.8mm of the dielectric substrate 4 in this embodiment into conventional calculation formulas in the art, the waveguide wavelength corresponding to the center frequency of 3.5GHz is calculated to be 95.2mm. The lengths of the first microstrip line 11 and the second microstrip line 12 of the main radiator are both 32.5mm, which is 0.34 times the waveguide wavelength; the lengths of the third microstrip line 21 and the fourth microstrip line 22 of the secondary radiator are both 22.5mm, which is 0.24 times the waveguide wavelength. Those skilled in the art can adjust the dimensions themselves according to actual needs in practical applications.

[0045] Therefore, the specific dimensions provided for the antenna structure of the present invention in this embodiment are as follows: the first microstrip line 11, the second microstrip line 12, the third microstrip line 21, and the fourth microstrip line 22 are all rectangular patch structures, wherein the length of the first microstrip line 11 and the second microstrip line 12 is 32.5 mm and the width is 2 mm; the length of the third microstrip line 21 and the fourth microstrip line 22 is 22.5 mm and the width is 8 mm; the length of the dielectric substrate 4 is 100 mm and the width is 30 mm; and the side length of the metal ground plane 5 is 300 mm.

[0046] The following data compares the base station antenna of the present invention with that of a traditional dipole base station antenna. Figures 3 to 5 The S-parameter diagram, simulated radiation pattern of the YOZ plane, and gain curve of the folded dipole base station antenna with extremely low profile of the present invention are given respectively; for data comparison, the profile height of the base station antenna of the present invention is 6mm. Figure 4 The 'h' in the annotation refers to the profile height.

[0047] The results show that the base station antenna of this invention operates between 3.4 GHz and 3.6 GHz with a return loss of less than -10 dB. Within the operating frequency range, the gain of the base station antenna is distributed between 9.2 and 9.7 dBi, reaching a maximum gain of 9.7 dBi at 3.5 GHz. The front-to-back ratio of the base station antenna at 3.5 GHz is 32.8 dB, and the half-power beamwidth is 94 degrees.

[0048] Figures 6 to 8 The S-parameter plots, simulated YOZ plane radiation patterns, and gain curves of a traditional dipole base station antenna with different profile heights (6, 9, 12, and 15 mm) are presented respectively. Figure 6 , Figure 7 The comment 'h' in the text refers to the height value of the profile.

[0049] The results show that the conventional antenna operates between 3.4 GHz and 3.6 GHz with a return loss of less than -10 dB. Within the operating frequency range, the gain of the conventional antenna is distributed between 8.2 and 8.4 dBi, reaching a maximum gain of 8.4 dBi at 3.45 GHz. With a profile height of 15 mm, the conventional antenna has a front-to-back ratio of 30 dB and a half-power beamwidth of 106 degrees at 3.5 GHz.

[0050] Compared with traditional dipole base station antennas, the folded dipole base station antenna with extremely low profile provided by this invention effectively reduces the antenna profile height and improves the antenna gain and directivity by adopting a differential feeding scheme without changing the operating frequency range.

Claims

1. A folded dipole base station antenna with very low profile, characterized by: The antenna comprises a main radiator, a secondary radiator, a dielectric plate (4) and a metal ground plane (5); the main radiator is arranged on the upper surface of the dielectric plate (4), the secondary radiator is arranged on the lower surface of the dielectric plate (4), and the metal ground plane (5) is arranged below the dielectric plate (4); a feed port is arranged between the main radiator and the secondary radiator, the feed port penetrates through the dielectric plate (4) and is connected with the main radiator and the secondary radiator respectively, and the feed port is used for providing differential feed for the main radiator and the secondary radiator. The main radiator comprises a first microstrip line (11) and a second microstrip line (12), and the first microstrip line (11) and the second microstrip line (12) are symmetrically arranged on both sides of the central axis of the upper surface of the dielectric plate (4). The secondary radiator comprises a third microstrip line (21) and a fourth microstrip line (22), and the third microstrip line (21) and the fourth microstrip line (22) are symmetrically arranged on both sides of the central axis of the lower surface of the dielectric plate (4). The feed port comprises a first end feed port (31) and a second end feed port (32), the first end feed port (31) is arranged at the end of the first microstrip line (11) close to the second microstrip line (12), and the second end feed port (32) is arranged at the end of the second microstrip line (12) close to the first microstrip line (11); the first end feed port (31) is also connected with the end of the third microstrip line (21) close to the fourth microstrip line (22), and the second end feed port (32) is also connected with the end of the fourth microstrip line (22) close to the third microstrip line (21). The first end feed port (31) is used for providing a first excitation signal for feeding the first microstrip line (11) and the third microstrip line (21), and the second end feed port (32) is used for providing a second excitation signal for feeding the second microstrip line (12) and the fourth microstrip line (22). The first microstrip line (11), the second microstrip line (12), the third microstrip line (21) and the fourth microstrip line (22) are all rectangular patch structures; the length of the first microstrip line (11) and the second microstrip line (12) is greater than the length of the third microstrip line (21) and the fourth microstrip line (22), and the width of the first microstrip line (11) and the second microstrip line (12) is smaller than the width of the third microstrip line (21) and the fourth microstrip line (22).

2. A folded dipole base station antenna with very low profile according to claim 1, characterized in that: The structure and size of the first microstrip line (11) and the second microstrip line (12) are the same.

3. A folded dipole base station antenna with very low profile according to claim 1, characterized in that: The structure and size of the third microstrip line (21) and the fourth microstrip line (22) are the same.

4. A folded dipole base station antenna with very low profile according to claim 1, characterized in that: The amplitudes of the first excitation signal and the second excitation signal are equal, and the phases are different by 180 degrees.

5. A folded dipole base station antenna with very low profile according to claim 1, characterized in that: The dielectric plate (4) adopts an FR-4 dielectric plate with a dielectric constant of 4.4 and a thickness of 0.8 mm.

6. A folded dipole base station antenna with very low profile according to claim 5, characterized in that: The distance between the metal ground plane (5) and the lower surface of the dielectric plate (4) is 6 mm.

7. A folded dipole base station antenna with very low profile according to claim 6, characterized in that: The length of the first microstrip line (11) and the second microstrip line (12) is 32.5mm, and the width is 2mm; the length of the third microstrip line (21) and the fourth microstrip line (22) is 22.5mm, and the width is 8mm; the length of the dielectric plate (4) is 100mm, and the width is 30mm; the side length of the metal ground plane (5) is 300mm.

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