A low profile base station antenna and dual polarized antenna array

Abstract

The application discloses a low-profile base station antenna and a dual-polarized antenna array, and the low-profile base station antenna comprises a first radiator, a second radiator, an upper dielectric plate, a lower dielectric plate, a metal ground and a support column, the first radiator is arranged on the top surface of the upper dielectric plate, the second radiator is arranged on the bottom surface of the upper dielectric plate, and the top points of the first radiator and the second radiator are arranged in alignment with each other; the upper dielectric plate is arranged on the top side of the lower dielectric plate and is connected through the support column; and the metal ground is arranged on the bottom surface of the lower dielectric plate. Through the structural design of the low-profile base station antenna, the multi-radiation arm technology or the artificial magnetic conductor technology mentioned in the background art is not needed, and only the input impedance of the antenna is adjusted to match by changing the structure and working mode of the antenna itself, so that the antenna profile is reduced to 0.094 lambda c (lambda c is the free space wavelength corresponding to 2350 MHz), and the wide frequency communication frequency band of 2010-2690 MHz can be covered.

Description

Technical Field

[0001] This invention belongs to the field of mobile communication technology, and particularly relates to a low-profile base station antenna and a dual-polarized antenna array. Background Technology

[0002] Base station antennas serve as both the entry and exit points for connecting mobile communication user information with base station equipment. They are also converters of electromagnetic wave energy carrying various types of information, playing a crucial role in the entire communication system. As second- to fifth-generation and even future sixth-generation communication systems will coexist for a long time, the space available for base station antennas across various frequency bands is constantly being compressed, leading to continuous advancements in base station antenna technology towards miniaturization and lower profiles.

[0003] According to the mirror principle, when a base station antenna is placed above a metal reflector, it can be considered equivalent to a two-element array consisting of the base station antenna and its mirror antenna. Analysis of the radiation pattern function of this array reveals that when the distance between the base station antenna and its mirror antenna is half the air wavelength (i.e., the distance between the base station antenna and the metal reflector is one-quarter the air wavelength), the antenna's main radiation direction is perpendicular to the metal reflector, and the gain reaches its maximum in the main radiation direction. However, placing the base station antenna at a height of one-quarter the air wavelength above the metal reflector does not align with the trend towards miniaturization of base station antennas. Researchers are employing various techniques to reduce the antenna's profile height.

[0004] In 2004, Steven R. Best proposed in his paper "Improving the Performance Properties of a Dipole Element Closely Spaced to a PEC Ground Plane" that using a folded dipole antenna with multiple radiating arms could compensate for the reduced antenna input impedance caused by a low profile, thus achieving a low profile. In this paper, the distance between the dipole antenna and the metal reflector was only 0.023λ. c (λ c (The free-space wavelength corresponding to 279.5MHz). In 2020, a utility model patent application with application number CN202022027285.1, entitled "A Low-Profile Broadband Base Station Antenna and Communication Equipment Based on AMC," proposed a method for reducing the antenna profile height by using a special periodic electromagnetic material, an artificial magnetic conductor, which can reduce the distance between the antenna and the metal reflector to 0.154λ. c (λ c (The free space wavelength corresponding to 2050MHz). Summary of the Invention

[0005] The purpose of this invention is to disclose a low-profile base station antenna and a dual-polarized antenna array. Through the structural configuration of the low-profile base station antenna described in this invention, it is not necessary to use the multi-radiating arm technology or artificial magnetic conductor technology mentioned in the background art. The antenna input impedance can be adjusted to match simply by changing the antenna's own structure and operating mode.

[0006] On the one hand, the objective of this invention is achieved through the following technical solution:

[0007] A low-profile base station antenna includes: a first radiator, a second radiator, an upper dielectric substrate, a lower dielectric substrate, a metal ground plane, and a support column. The first radiator is disposed on the top surface of the upper dielectric substrate, and the second radiator is disposed on the bottom surface of the upper dielectric substrate, with one vertex of the first radiator and the second radiator aligned with each other. The upper dielectric substrate is disposed on the top side of the lower dielectric substrate and connected to it via the support column. The metal ground plane is disposed on the bottom surface of the lower dielectric substrate.

[0008] According to a preferred embodiment, the first radiator is obtained by providing a first sector-shaped groove near the top corner of a square patch, and providing a second sector-shaped groove and a third sector-shaped groove at two adjacent top corners.

[0009] According to a preferred embodiment, the shape of the second radiator is similar to that of the first radiator.

[0010] According to a preferred embodiment, a power supply port is provided near the vertex position where the first radiator and the second radiator are aligned with each other. The inner core of the coaxial line of the power supply port is connected to the first radiator, and the outer metal wire of the coaxial line of the power supply port is connected to the second radiator to complete the feeding of electrical signals.

[0011] According to a preferred embodiment, the upper medium plate is fixed to the lower medium plate at a position 12mm directly above it by a support column.

[0012] According to a preferred embodiment, the upper and lower dielectric substrates are FR-4 dielectric substrates with a thickness of 1.6 mm and a dielectric constant of 4.4.

[0013] According to a preferred embodiment, the side length of the first radiator is 63 mm, and the side length of the second radiator is 53 mm.

[0014] According to a preferred embodiment, the first radiator is disposed on the top surface of the upper dielectric substrate by printing; the second radiator is disposed on the bottom surface of the upper dielectric substrate by printing.

[0015] According to a preferred embodiment, the metal ground is printed onto the bottom surface of the lower dielectric substrate.

[0016] On the other hand, the present invention also discloses:

[0017] A dual-polarized antenna array includes four antennas: a first antenna, a second antenna, a third antenna, and a fourth antenna. The first and third antennas are arranged along a first direction, and the second and third antennas are arranged along a second direction. The two antennas arranged in the first direction are perpendicular to the polarization direction of the two antennas arranged in the second direction. The first antenna, the second antenna, the third antenna, and the fourth antenna are the aforementioned low-profile base station antennas.

[0018] The aforementioned main solution of the present invention and its various further alternative solutions can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed by the present invention. Those skilled in the art, after understanding the solution of the present invention, will realize that there are many combinations based on existing technology and common knowledge, all of which are technical solutions to be protected by the present invention, and will not be exhaustively listed here.

[0019] The beneficial effects of this invention are:

[0020] The low-profile base station antenna design of this invention eliminates the need for the multi-radiating arm technology or artificial magnetic conductor technology mentioned in the background art. It only relies on changing the antenna's own structure and operating mode to adjust the antenna input impedance to match, thereby reducing the antenna profile to 0.094λc (λc is the free space wavelength corresponding to 2350MHz) and covering the 2010-2690MHz wideband communication band. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a low-profile base station antenna;

[0022] Figure 2 This is a schematic diagram of the first radiator structure of a low-profile base station antenna.

[0023] Figure 3 This is the S-parameter diagram of a low-profile base station antenna;

[0024] Figure 4 This is the simulated radiation pattern of a low-profile base station antenna in the XOZ plane;

[0025] Figure 5 This is a schematic diagram of a dual-polarized antenna array composed of low-profile base station antennas.

[0026] Figure 6 This is an S-parameter diagram of a dual-polarized antenna array composed of low-profile base station antennas.

[0027] Figure 7 This is a simulated radiation pattern of a dual-polarized antenna array composed of low-profile base station antennas in the XOZ plane.

[0028] Wherein, 1-first radiator, 11-square patch, 12-first sector groove, 13-second sector groove, 14-third sector groove, 2-second radiator, 3-upper dielectric plate, 4-lower dielectric plate, 5-metal ground, 6-support column. Detailed Implementation

[0029] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0032] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] Furthermore, it should be noted that, unless otherwise specified, the structures, connections, positions, power sources, etc. involved in this invention are all things that a person skilled in the art can know without creative effort based on the prior art.

[0035] Example 1:

[0036] refer to Figure 1 As shown in the figure, a low-profile base station antenna is illustrated. The low-profile base station antenna includes: a first radiator 1, a second radiator 2, an upper dielectric substrate 3, a lower dielectric substrate 4, a metal ground 5, and a support column 6.

[0037] Preferably, the first radiator 1 is disposed on the top surface of the upper dielectric plate 3, and the second radiator 2 is disposed on the bottom surface of the upper dielectric plate 3, with one vertex of the first radiator 1 and the second radiator 2 aligned with each other.

[0038] Furthermore, the first radiator 1 is printed on the top surface of the upper dielectric substrate 3; the second radiator 2 is printed on the bottom surface of the upper dielectric substrate 3.

[0039] Preferably, the upper dielectric substrate 3 is disposed on the top side of the lower dielectric substrate 4 and connected by a support column 6. The metal ground plane 5 is disposed on the bottom surface of the lower dielectric substrate 4. The metal ground plane 5 is disposed on the bottom surface of the lower dielectric substrate 4 by printing. The upper dielectric substrate 3 is fixed to the lower dielectric substrate 4 at a position 12mm directly above it by the support column 6. The antenna operates in the frequency band of 2010-2690MHz, with a center frequency of 2350MHz. Calculations show that the wavelength corresponding to the center frequency of 2350MHz is 127.66mm (λ). c Converting the 12mm antenna profile into an expression for the wavelength corresponding to the center frequency, we get 0.094λ. c In this embodiment of the invention, both the upper dielectric substrate 3 and the lower dielectric substrate 4 are FR-4 dielectric substrates with a thickness of 1.6 mm and a dielectric constant of 4.4. The dielectric constant and thickness of the upper dielectric substrate 3 and the lower dielectric substrate 4 can be selected according to actual needs.

[0040] Preferably, the side lengths of the first radiator 1 and the second radiator 2 are designed according to the requirements of their resonant frequency. The resonant frequency of the antenna can be adjusted by adjusting the side lengths of the first radiator 1 and the second radiator 2. The side length of the first radiator 1 is 63mm, approximately 0.5λc, and the side length of the second radiator 2 is 53mm, approximately 0.4λc. Technicians can adjust the dimensions themselves according to actual needs.

[0041] Further, refer to Figure 2As shown, the first radiator 1 is an irregular structure. The first radiator 1 is obtained by setting a first sector-shaped slot 12 near the top corner of a square patch 11, and setting a second sector-shaped slot 13 and a third sector-shaped slot 14 at adjacent top corners. The shape of the second radiator 2 is similar to that of the first radiator 1. The purpose of setting several sector-shaped slots is to extend the current path and expand the bandwidth. Researchers can design different structures for the first radiator 1 and the second radiator 2 according to the actual required frequency band.

[0042] A power supply port is provided near the apex position where the first radiator 1 and the second radiator 2 are aligned with each other. The inner core of the coaxial line of the power supply port is connected to the first radiator 1, and the outer metal wire of the coaxial line of the power supply port is connected to the second radiator 2 to complete the feeding of electrical signals.

[0043] Traditional base stations use a symmetrical dipole with an arm length of about half a wavelength (the overall length of the radiator is approximately 0.5λc) as the radiator, placed a quarter-wavelength above a reflector to generate unidirectional radiation. As the height of the half-wave dipole gradually decreases, its input impedance drops from 50 ohms to a few ohms, significantly reducing impedance matching. Theoretically, to address the reduced antenna input impedance caused by the lower profile, simply increasing the antenna's input impedance is sufficient. There are two methods to increase the antenna's input impedance: one is to add an additional tuning circuit, and the other is to replace the original half-wave dipole with an antenna with a higher input impedance. Since the former leads to reduced antenna efficiency and gain, this patent adopts the latter, replacing the original half-wave dipole with an antenna with a higher input impedance. According to antenna theory, a symmetrical dipole with an arm length of about one wavelength (also known as a full-wave dipole) has an input impedance of approximately 1314Ω when operating in free space. A higher input impedance helps to offset the decrease in input impedance caused by the lower profile. However, using a true full-wave dipole antenna would double the antenna length, hindering miniaturization. Furthermore, the input impedance of a full-wave dipole antenna is significantly different from the optimal matching value of 50 ohms, increasing the difficulty of impedance matching. This patent proposes a low-profile base station antenna. The radiator comprises a first radiator 1 printed on the upper surface of the upper dielectric substrate 3 and a second radiator 2 printed on the lower surface of the upper dielectric substrate 3, with lengths of 0.5λc and 0.4λc respectively. The overall length of the radiator remains 0.5λc, comparable to that of a half-wave dipole antenna. The first radiator 1 and the second radiator 2 are placed on two layers with an asymmetrical structure, enabling them to operate in full-wave mode. Their input impedance is significantly reduced compared to the 1314Ω input impedance of a true full-wave dipole antenna, ensuring that the antenna input impedance is rematched to approximately 50Ω.

[0044] Figure 3 and 4The S-parameter plots and simulated XOZ radiation patterns of the antenna in this specific embodiment are presented. The results show that this antenna achieves good reflection coefficients (|S... 11 When the voltage is less than -10dB, it can cover 2010-2690MHz, including the TD-LTE frequency bands of China's three major operators. Figure 3 The dB beamwidth is approximately 65°. It is worth noting that the direction of the maximum radiation pattern deviates from 0° by about 15°. This phenomenon is caused by the fact that the first radiator 1 and the second radiator 2 are not perfectly symmetrical. This problem will be well resolved after they are assembled into an array.

[0045] Example 2

[0046] This embodiment discloses a dual-polarized antenna array. In base station antenna design, multiple antennas need to be arranged in a planar array to obtain high gain. Figure 5 Given Figure 1 The diagram shows a dual-polarized antenna array composed of antennas.

[0047] The dual-polarized antenna array includes four antennas: a first antenna, a second antenna, a third antenna, and a fourth antenna. The first and third antennas are arranged along a first direction, and the second and third antennas are arranged along a second direction. The two antennas arranged in the first direction are perpendicular to the polarization direction of the two antennas arranged in the second direction. The first antenna, the second antenna, the third antenna, and the fourth antenna adopt the low-profile base station antenna structure of the aforementioned embodiment 1.

[0048] Specifically, refer to Figure 5 As shown in the diagram, this schematic includes two antennas placed along the -45° direction (corresponding to port 1 and port 3, respectively) and two additional antennas placed along the +45° direction. The polarization directions of the two antennas placed along the -45° direction and the two antennas placed along the +45° direction are perpendicular, enabling dual-polarization operation. Researchers can place multiple antennas in both the -45° and +45° directions according to the antenna system gain requirements. The center points of the two antennas placed along the -45° direction are 100mm apart (approximately 0.78λ). c The antenna spacing is generally selected to be 0.5 to 0.8λ. cThe specific values ​​can be adjusted according to the beamwidth requirements. To ensure that the main radiation direction of the two antennas placed along the -45° direction forms a binary array along the 0° direction, a phase difference of 180 degrees must be maintained when feeding ports 1 and 3. This allows the far-field radiation of the two antennas to cancel each other out, thus solving the radiation pattern deflection problem caused by the non-perfectly symmetrical structure of the first radiator 1 and the second radiator 2 of a single antenna. The spacing and feeding method of the center points of the two antennas placed along the +45° direction are the same as those of the two antennas placed along the -45° direction. When multiple antennas are set up in the -45° and +45° directions respectively, the antenna spacing and feeding method remain the same.

[0049] Figures 6-7 Given Figure 5 The S-parameter plot and simulated XOZ plane radiation pattern of the dual-polarized antenna array are shown. From Figure 6 As can be seen from this, the dual-polarized antenna array has a high reflection coefficient (|S 11 When the voltage drop is less than -10dB, it still operates in the 2010-2690MHz range, covering the TD-LTE frequency bands of China's three major operators, and the isolation between each antenna port is (-|S). 21 |,-|S 31 |,-|S 41 |) All remained above 22dB. From Figure 7 As can be seen, when the two antennas in the -45° direction are given equal-amplitude, phase-inverse (equal amplitude, 180° phase difference) excitation at ports 1 and 3 respectively, the main polarization direction of the antennas... Figure 3 The dB beamwidth is approximately 33°, the maximum radiation direction points to 0°, and the cross-polarization is relatively small.

[0050] The low-profile base station antenna proposed in this invention adjusts the antenna input impedance solely by changing the antenna's own structure and operating mode, ultimately reducing the antenna profile to 0.094λ. c (λ c It has a free-space wavelength corresponding to 2350MHz and can cover the 2010-2690MHz communication frequency band, which is a brand-new solution for achieving low antenna profile.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-profile base station antenna, characterized in that, The low-profile base station antenna includes: a first radiator (1), a second radiator (2), an upper dielectric substrate (3), a lower dielectric substrate (4), a metal ground (5), and a support column (6). The first radiator (1) is disposed on the top surface of the upper dielectric plate (3), and the second radiator (2) is disposed on the bottom surface of the upper dielectric plate (3), and one vertex of the first radiator (1) and the second radiator (2) are aligned with each other. The upper medium plate (3) is disposed on the top side of the lower medium plate (4) and connected by a support column (6); the metal ground (5) is disposed on the bottom surface of the lower medium plate (4); The first radiator (1) is obtained by setting a first sector groove (12) near the top corner of a square patch (11), and setting a second sector groove (13) and a third sector groove (14) at two adjacent top corners; The shape of the second radiator (2) is similar to that of the first radiator (1); The side length of the first radiator (1) is 63 mm, and the side length of the second radiator (2) is 53 mm. A power supply port is provided near the vertex position where the first radiator (1) and the second radiator (2) are aligned with each other. The inner core of the coaxial line of the power supply port is connected to the first radiator (1), and the outer metal wire of the coaxial line of the power supply port is connected to the second radiator (2) to complete the feeding of electrical signals.

2. The low-profile base station antenna as described in claim 1, characterized in that, The upper medium plate (3) is fixed 12mm above the lower medium plate (4) by a support column (6).

3. The low-profile base station antenna as described in claim 1, characterized in that, The upper dielectric substrate (3) and the lower dielectric substrate (4) are FR-4 dielectric substrates with a thickness of 1.6 mm and a dielectric constant of 4.

4.

4. The low-profile base station antenna as described in claim 1, characterized in that, The first radiator (1) is printed on the top surface of the upper dielectric substrate (3); the second radiator (2) is printed on the bottom surface of the upper dielectric substrate (3).

5. The low-profile base station antenna as described in claim 1, characterized in that, The metal ground (5) is printed on the bottom surface of the lower medium plate (4).

6. A dual-polarized antenna array, characterized in that, The dual-polarized antenna array includes four antennas: a first antenna, a second antenna, a third antenna, and a fourth antenna. The first and third antennas are arranged along the first direction, and the second and third antennas are arranged along the second direction; and the polarization directions of the two antennas arranged in the first direction are perpendicular to the polarization directions of the two antennas arranged in the second direction. The first antenna, the second antenna, the third antenna, and the fourth antenna are low-profile base station antennas as described in any one of claims 1 to 5.

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