Low profile small size dual-band dual-polarized wall-mount antenna

Abstract

The application discloses a low-profile small-size dual-frequency dual-polarization wall-hanging antenna, belonging to the antenna field, which comprises a first medium plate, a second medium plate, a third medium plate, a metal isolation wall, a high-frequency antenna, a one-to-two differential feeding power divider, a metal patch of an electromagnetic bandgap structure, a square patch and a high-frequency antenna Г-shaped feeding structure. The low-frequency antenna uses a square rotating ring radiation patch, which is convenient for placing the high-frequency antenna in the middle, reduces the coupling of the antenna and greatly reduces the overall size of the antenna. The low-frequency antenna changes the phase of low-frequency reflected waves by using the electromagnetic bandgap structure, effectively reduces the overall profile height of the dual-frequency dual-polarization antenna (reduces to 0.1 times of the low-frequency wavelength). Meanwhile, the high-low-frequency metal isolation wall effectively reduces the coupling between the high-low-frequency antennas. The overall structure of the antenna is relatively simple, the different-frequency port isolation is greater than 25 dB, the same-frequency port isolation is greater than 22 dB, the low-frequency antenna operating frequency band is 0.88-0.96 GHz, and the high-frequency antenna operating frequency band is 1.71-2.69 GHz.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and more particularly to a low-profile, small-size dual-frequency dual-polarization wall-mounted antenna. Background Technology

[0002] In recent years, with the development of wireless communication systems towards integration and miniaturization, common-aperture antennas have attracted widespread attention due to their ability to integrate antenna elements of multiple frequency bands within the same physical aperture, effectively saving installation space. Among them, dual-band common-aperture antennas have important application value in mobile communication, satellite navigation, and radar systems.

[0003] To achieve system miniaturization and low-profile design, engineering practice often attempts to reduce the profile height of low-frequency antennas. However, low-profile structures introduce a series of technical challenges. First, as the antenna profile height decreases, surface wave coupling between antenna elements of different frequency bands increases, leading to deterioration in inter-frequency isolation. Traditional low-profile dual-frequency common-aperture antennas, without additional isolation measures, exhibit low inter-frequency isolation, severely impacting system transmission and reception performance. Second, low-profile structures also cause a decrease in antenna gain and distortion of the radiation pattern, thereby reducing the antenna's radiation efficiency and beam coverage quality.

[0004] To improve isolation, some existing technologies attempt to introduce frequency-selective surface structures and electromagnetic bandgap structures between antennas. However, while maintaining low profile characteristics, effectively improving inter-frequency isolation to an engineering-practical level, and simultaneously suppressing gain drop and pattern distortion, remains a challenge in current designs. Therefore, there is an urgent need to propose a dual-frequency, dual-polarization wall-mounted antenna design that can simultaneously achieve high inter-frequency isolation, good gain characteristics, and a stable pattern under ultra-low profile conditions. Summary of the Invention

[0005] The purpose of this invention is to solve the aforementioned problems in the prior art and provide a low-profile, small-size dual-band dual-polarization wall-mounted antenna. Through innovative structural design, this antenna can stably support dual-polarization operation in two independent frequency bands. Its low profile and compact size facilitate system integration. The antenna operates in the 0.88~0.96GHz and 1.71~2.69GHz frequency bands while maintaining good radiation performance, meeting the comprehensive requirements of 5G communication equipment for antenna miniaturization, multi-band operation, and high performance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A low-profile, small-size dual-band, dual-polarization wall-mounted antenna, comprising:

[0008] A first dielectric substrate, a second dielectric substrate, and a third dielectric substrate are stacked together, and the lower surface of the first dielectric substrate is provided with a metal ground.

[0009] A high-frequency antenna is positioned above the first dielectric substrate, passes through an opening in the central region of the second dielectric substrate, and is located in the middle of the third dielectric substrate;

[0010] The low-frequency antenna includes a square rotating ring radiating patch disposed on the upper surface of a third dielectric substrate. The square rotating ring radiating patch is arranged around a high-frequency antenna so that the low-frequency antenna and the high-frequency antenna form a coaxial nested structure.

[0011] The electromagnetic bandgap structure includes multiple metal patches disposed on the upper surface of a second dielectric substrate, and multiple copper pillars passing through the second dielectric substrate and electrically connecting the metal patches to a metal ground. The electromagnetic bandgap structure is located below the low-frequency antenna.

[0012] A metal partition wall, erected on the first dielectric substrate and located between the radiating elements of the high-frequency antenna and the low-frequency antenna, is used to suppress spatial coupling.

[0013] Two 1-to-2 differential power dividers are set on the upper surface of the first dielectric substrate and connected to a square rotating ring radiating patch through a power feed copper pillar to differentially feed the low-frequency antenna.

[0014] The low-frequency antenna feed coaxial line has its outer conductor connected to the metal ground and its inner conductor connected to the input terminal of the 1-to-2 differential feed power divider.

[0015] The high-frequency antenna feed coaxial line has its outer conductor connected to the metal ground of the first dielectric substrate, and its inner conductor connected to the feed structure of the high-frequency antenna.

[0016] The copper pillars in the electromagnetic bandgap structure are welded or connected to the metal ground at their bottom ends and connected to the corresponding metal patches at their top ends; the metal patches are periodically arranged on the upper surface of the second dielectric substrate.

[0017] The first dielectric substrate has a slot, and the bottom of the metal isolation wall is fixed in the slot. The metal isolation wall is a vertical metal wall surrounding the high-frequency antenna.

[0018] The 1-to-2 differential power divider includes a jumper structure, and a metallized via is provided on the first dielectric board. The jumper is connected to the power divider network through the metallized via. The two 1-to-2 differential power dividers correspond to the two orthogonal polarization ports of the low-frequency antenna, respectively.

[0019] The high-frequency antenna is an aluminum cast model with a Г-shaped feed structure on it. The inner conductor of the high-frequency antenna feed coaxial line is connected to the Г-shaped feed structure.

[0020] The upper surface of the third dielectric plate is also provided with four square patches, each of which is connected to the metal ground through a corresponding copper pillar.

[0021] The present invention also includes a plurality of nylon pillars, wherein the first, second and third media plates are provided with corresponding non-metallized vias, and the nylon pillars pass through the non-metallized vias and support and fix the relative distance between each media plate.

[0022] The low-frequency antenna operates in the frequency band of 0.88~0.96GHz, and the high-frequency antenna operates in the frequency band of 1.71~2.69GHz; the isolation between different frequency ports is greater than 25dB, and the isolation between the same frequency ports is greater than 22dB.

[0023] The electromagnetic bandgap structure is used to change the phase of the low-frequency reflected wave so that the overall profile height of the antenna does not exceed 0.1 times the low-frequency wavelength.

[0024] Compared with the prior art, the beneficial effects achieved by the technical solution of this invention are:

[0025] 1. The present invention relates to a low-profile, small-size dual-frequency dual-polarization wall-mounted antenna, wherein an electromagnetic bandgap structure is arranged below the low-frequency antenna, and the low-frequency electromagnetic wave reflection phase is controlled by the structure. The overall height of the antenna is reduced by adopting a structural stacking design, thereby reducing the profile height of the low-frequency antenna. The profile height of the overall antenna is reduced from 0.25 times the low-frequency wavelength to 0.1 times the low-frequency wavelength, thus achieving an ultra-low profile antenna structure configuration.

[0026] 2. The present invention relates to a low-profile, small-size dual-frequency dual-polarization wall-mounted antenna. Unlike the traditional dual-frequency dual-polarization wall-mounted antenna with its left-right arrangement, the present invention uses a coaxial nested structure for the high-frequency antenna and the low-frequency antenna. The coaxial integrated arrangement achieves a compact overall structure, significantly reducing the physical size of the antenna in the horizontal direction, resulting in a smaller overall size.

[0027] 3. The present invention relates to a low-profile, small-size dual-frequency dual-polarization wall-mounted antenna, which uses a square rotating ring low-frequency antenna and places the high-frequency antenna in the middle, thereby reducing the size of the dual-frequency dual-polarization wall-mounted antenna.

[0028] 4. The present invention relates to a low-profile, small-size dual-frequency dual-polarization wall-mounted antenna, which sets up a vertical metal isolation wall structure between the high-frequency and low-frequency antenna radiating elements. Through the spatial isolation and electromagnetic shielding structure design of the metal isolation wall, spatial coupling and electromagnetic crosstalk between the high-frequency and low-frequency radiating elements are suppressed, and the isolation performance of the different frequency ports is greatly improved.

[0029] 5. The present invention relates to a low-profile, small-size dual-frequency dual-polarization wall-mounted antenna with an isolation greater than 25dB at the different frequency ports and an isolation greater than 22dB at the same frequency ports, which can be applied to indoor distributed antenna systems.

[0030] 6. The antenna described in this invention adopts a compact, low-profile structure and can be integrated as an array unit in indoor distributed antenna systems or micro base stations, serving as a low-profile, high-isolation unit antenna group. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a low-profile, small-size dual-frequency, dual-polarized wall-mounted antenna according to the present invention.

[0032] Figure 2 This is a schematic diagram of the etched metal structure on the upper surface of the first dielectric substrate.

[0033] Figure 3 This is a schematic diagram of the etched metal structure on the lower surface of the first dielectric substrate.

[0034] Figure 4 This is a schematic diagram of the etched metal structure on the upper surface of the second dielectric substrate.

[0035] Figure 5 This is a schematic diagram of the etched metal structure on the upper surface of the third dielectric substrate.

[0036] Figure 6 The figure shows the simulation results of the S-parameters and gain of the low-frequency antenna as a function of frequency.

[0037] Figure 7 The figure shows the simulation results of the S-parameters and gain of the high-frequency antenna as a function of frequency.

[0038] Figure 8 The figure shows the simulation results of the port isolation of low-frequency and high-frequency antennas as a function of frequency in the low-frequency band.

[0039] Figure 9 The figure shows the simulation results of the port isolation of low-frequency and high-frequency antennas as a function of frequency in the high-frequency band.

[0040] Figure 10 The simulation results show the E-plane and H-plane radiation patterns of the low-frequency antenna at 0.92 GHz when it is fed from port 1.

[0041] Figure 11 The simulation results show the E-plane and H-plane radiation patterns of the high-frequency antenna at 1.7 GHz when fed from port 3.

[0042] Figure 12 The simulation results show the E-plane and H-plane radiation patterns of the high-frequency antenna at 2.2 GHz when it is fed from port 3.

[0043] Figure 13 The simulation results show the E-plane and H-plane radiation patterns of the high-frequency antenna at 2.7 GHz when fed from port 3. Detailed Implementation

[0044] To make the technical problems, technical solutions, and beneficial effects of this invention clearer and more understandable, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0045] Example 1

[0046] like Figures 1 to 5 As shown in the figure, this embodiment provides a low-profile, small-size dual-band dual-polarization wall-mounted antenna, mainly comprising a first dielectric substrate 1, a second dielectric substrate 2, a third dielectric substrate 3, a metal isolation wall 4, a high-frequency antenna 5, an electromagnetic bandgap structure, a 1-to-2 differential power divider 7, and corresponding feeding and support structures. The three dielectric substrates are stacked sequentially from bottom to top at intervals and supported and positioned by multiple nylon pillars to form a stable three-dimensional antenna structure.

[0047] The first dielectric substrate 1 is located at the bottom layer, and its lower surface is fully printed with a metal ground plane 6, which provides an RF ground reference plane for the entire antenna. This metal ground plane also serves as the common ground plane for both the low-frequency and high-frequency antennas. The upper surface of the first dielectric substrate 1 is printed with two 1-to-2 differential feed power dividers 7. The two power dividers correspond to the two orthogonal polarization ports of the low-frequency antenna, respectively, and are used to convert the single-ended feed signal into differential signals with equal amplitude and 180-degree phase difference, so as to differentially feed the low-frequency antenna.

[0048] To facilitate the installation and feeding of the high-frequency antenna, two non-metallic vias 8 and two non-metallic semi-circular vias 9 are provided on the first dielectric substrate 1. The outer conductor of the high-frequency antenna feed coaxial line is soldered to the metal ground 6, and its inner conductor passes upward through the non-metallic vias 8 and connects to the Г-shaped feed structure of the high-frequency antenna 5. The semi-circular vias 9 are used for grounding and position avoidance during the installation of the high-frequency antenna. The first dielectric substrate 1 also has eight non-metallic vias 10 at specific locations on its edge and inside for inserting nylon pillars to achieve precise support and spacing control between the three dielectric substrates.

[0049] The construction of the electromagnetic bandgap structure requires a reliable connection between a large number of copper pillars and the metal ground 6. Therefore, 108 non-metallic vias 11 are provided on the first dielectric substrate 1. These vias are used for soldering or tightly fitting the lower ends of the copper pillars of the electromagnetic bandgap structure. Simultaneously, to accommodate the low-frequency antenna feed and the grounding requirements of the square patch, the first dielectric substrate 1 also has 8 non-metallic vias 14, 4 of which are used for the low-frequency antenna feed copper pillars 12, and the other 4 are used for the square patch grounding copper pillars 13. The low-frequency antenna feed coaxial line 26 is installed through 2 non-metallic vias 15. The outer conductor of this coaxial line is soldered to the metal ground 6, and the inner conductor passes upward through the via and connects to the feed copper pillar, thereby introducing the radio frequency signal into the 1-to-2 differential feed power divider 7. Furthermore, slots 16 are provided on the first dielectric substrate 1 for fixing the bottom of the metal isolation wall 4.

[0050] The second dielectric substrate 2 is located above the first dielectric substrate 1. Its main function is to support the electromagnetic bandgap structure and provide clearance space for the high-frequency antenna. The upper surface of the second dielectric substrate 2 is printed with 108 metal patches 17 of the electromagnetic bandgap structure. These patches are arranged in a periodic pattern to form an artificial electromagnetic surface. For each metal patch 17, a non-metallized via 18 is formed on the second dielectric substrate 2, totaling 108, for mounting copper pillars. During assembly, the lower end of the copper pillar passes through the corresponding via 11 on the first dielectric substrate 1 and is soldered to the metal ground 6. The upper end passes through the via 18 on the second dielectric substrate 2 and is soldered or electrically connected to the metal patch 17. This allows each metal patch 17 to be DC grounded through the copper pillar, effectively forming a parallel resonant structure in the microwave band. This changes the reflection phase of low-frequency electromagnetic waves in this region, thereby reducing the profile height of the low-frequency antenna.

[0051] To accommodate the high-frequency antenna, a square hole 20 is provided in the central region of the second dielectric substrate 2. The inner contour of the square hole is adapted to the shape of the high-frequency antenna 5, allowing the high-frequency antenna to pass sequentially through the square hole of the second dielectric substrate 2 from above the first dielectric substrate 1 and finally extend to the middle space of the third dielectric substrate 3. The second dielectric substrate 2 is also provided with eight non-metallic vias 19 for passing through nylon pillars to achieve a stable connection with the upper and lower dielectric substrates.

[0052] The second dielectric substrate 2 also has 8 non-metallic vias, which correspond to the installation positions of the low-frequency feed copper pillar 12 and the square patch grounding copper pillar 13 on the first dielectric substrate, so that these copper pillars can pass through.

[0053] The third dielectric substrate 3 is located on the top layer, and its upper surface is printed with the core radiating structure of the low-frequency antenna—a square rotating ring radiating patch 21. This patch is a rotating ring with an opening, arranged around the central area, thus forming a space inside to accommodate the high-frequency antenna 5. This achieves a coaxial nested layout of the low-frequency and high-frequency antennas, significantly reducing the overall horizontal size of the antenna. Around the square rotating ring radiating patch 21, four square patches 22 are also printed on the upper surface of the third dielectric substrate 3. These four square patches, as part of the parasitic unit or grounding structure, can further broaden the impedance bandwidth or optimize the radiation pattern.

[0054] To facilitate assembly, the third dielectric substrate 3 has four non-metallic vias 23 at its four corners for passing through nylon posts connected to the first dielectric substrate 1. Simultaneously, four non-metallic vias 24 are also provided, corresponding to the four feed copper posts of the low-frequency antenna. The feed copper posts 12 pass through these vias, with their upper ends soldered to corresponding pads on the square rotating ring radiating patch 21, and their lower ends connected to the output of the 1-to-2 differential feed power divider 7 on the first dielectric substrate 1. Additionally, each square patch 22 has a corresponding non-metallic via 25 through which the square patch grounding copper post 13 passes, with its upper end soldered to the square patch 22 and its lower end connected to the metal ground 6, thereby DC grounding the square patch 22.

[0055] The metal isolation wall 4 is a vertical metal wall, whose bottom is inserted into the slot 16 on the first dielectric plate 1 and welded in place. The wall extends upwards above the third dielectric plate 3 and is spatially located between the radiating elements of the high-frequency antenna 5 and the low-frequency antenna (i.e., the inner area of ​​the square rotating ring radiating patch 21). This metal isolation wall can effectively block the spatial coupling and surface wave propagation between the high-frequency and low-frequency radiating elements, significantly improving the isolation between different frequency ports.

[0056] The high-frequency antenna 5 is a three-dimensional radiating element cast in aluminum. Its bottom is fixed above the first dielectric substrate 1, and its top radiates through a square hole 20 in the second dielectric substrate 2. This high-frequency antenna includes a Г-shaped feed structure, which is connected to the inner conductor of the high-frequency antenna feed coaxial line to achieve broadband single-port or dual-polarization feeding. In this embodiment, the high-frequency antenna also supports dual-polarization operation, fed by two independent ports. Port isolation can be achieved through symmetrical layout and internal structure optimization.

[0057] The low-frequency antenna's feed network employs a compact 1-to-2 differential feed power divider 7. This power divider is printed on the upper surface of the first dielectric substrate 1. Its input port is connected to the inner conductor copper pillar of the low-frequency antenna feed coaxial line 26, and its output port is connected to four opposite feed positions on the square rotating ring radiating patch 21 via corresponding feed copper pillars 12. To avoid line crossings, the power divider network includes a jumper structure. Two metallized vias are opened at specific locations on the first dielectric substrate 1. One end of the jumper is soldered to the upper end of the via and connected to the power divider circuitry, while the other end passes through the via from the lower surface of the dielectric substrate, thus bridging the signal and ensuring the amplitude and phase accuracy of the differential feed.

[0058] Through the aforementioned structural stacking design, the antenna of this invention achieves ultra-low profile characteristics. The low-frequency antenna operates in the 0.88~0.96GHz frequency band. The electromagnetic bandgap structure beneath it alters the phase of the low-frequency reflected wave, effectively compressing the antenna profile height, which originally required approximately 0.25 times the low-frequency wavelength, to below 0.1 times the low-frequency wavelength, thus achieving an extremely low overall height. Simultaneously, the high-frequency and low-frequency antennas are arranged coaxially and nested, significantly reducing the horizontal projected area compared to the traditional side-by-side arrangement, resulting in a more compact overall size.

[0059] To further illustrate the technical effects of this embodiment, Figures 6 to 13 The electromagnetic simulation results of the antenna are presented.

[0060] like Figure 6 The figure shown is a simulation result of the S-parameters and gain of the low-frequency antenna as a function of frequency according to an embodiment of the present invention. The operating frequency band of the low-frequency antenna is 0.88~0.96GHz. The simulated return loss within the operating bandwidth is less than -10dB, the port isolation is greater than 22dB, and the average gain is 8.33dBi.

[0061] like Figure 7 The figure shown is a simulation result of the S-parameters and gain of the high-frequency antenna as a function of frequency in an embodiment of the present invention. The high-frequency antenna operates in the frequency band of 1.71~2.69GHz. The simulated return loss within the operating bandwidth is less than -10dB, the port isolation is greater than 30dB, and the average gain is 8.57dBi.

[0062] like Figure 8 The figure shown is a simulation result of the port isolation of the low-frequency antenna and the high-frequency antenna in the embodiment of the present invention as a function of frequency in the low-frequency band. The port isolation is greater than 30dB.

[0063] like Figure 9 The figure shown is a simulation result of the port isolation of the low-frequency antenna and the high-frequency antenna in the embodiment of the present invention as a function of frequency in the high-frequency band. The port isolation is greater than 25dB.

[0064] like Figure 10The figure shown is a simulation result of the low-frequency antenna in the E-plane and H-plane at a frequency of 0.92 GHz according to an embodiment of the present invention. The low-frequency antenna pattern shows a directional radiation mode.

[0065] like Figure 11 The figure shown is a simulation result of the E-plane and H-plane radiation patterns of the high-frequency antenna at a frequency of 1.7 GHz according to an embodiment of the present invention. The high-frequency antenna radiation pattern exhibits a directional radiation mode.

[0066] like Figure 12 The figure shown is a simulation result of the E-plane and H-plane radiation patterns of the high-frequency antenna at a frequency of 2.2 GHz according to an embodiment of the present invention. The high-frequency antenna radiation pattern exhibits a directional radiation mode.

[0067] like Figure 13 The figure shown is a simulation result of the E-plane and H-plane radiation patterns of the high-frequency antenna at 2.7 GHz in an embodiment of the present invention. The high-frequency antenna radiation pattern exhibits a directional radiation mode.

[0068] Experiments show that, compared to other dual-frequency dual-polarized wall-mounted antennas, the dual-frequency dual-polarized wall-mounted antenna of this invention, with its low profile and small size, utilizes an electromagnetic bandgap structure to alter the phase of the low-frequency reflected wave, reducing the antenna's profile height from 0.25 times the low-frequency wavelength to 0.1 times the low-frequency wavelength. Unlike the traditional left-right arrangement of dual-frequency dual-polarized wall-mounted antennas, this antenna is coaxially arranged, resulting in a smaller overall size. This invention relates to a low-profile, small-size dual-band dual-polarized wall-mounted antenna, which uses a square rotating ring low-frequency antenna with a high-frequency antenna placed in the middle, thus reducing the size of the dual-band dual-polarized wall-mounted antenna. The invention also relates to a low-profile, small-size dual-band dual-polarized wall-mounted antenna that uses a metal wall to reduce coupling between high- and low-frequency antenna elements and improve the isolation of different frequency ports. Furthermore, this invention relates to a low-profile, small-size dual-band dual-polarized wall-mounted antenna with an isolation greater than 25dB for different frequency ports and greater than 22dB for the same frequency port, which can be applied to indoor distributed antenna systems.

[0069] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to these embodiments. Any modifications, combinations and simplifications made without departing from the principles and essence of the present invention are included within the protection scope of the present invention.

Claims

1. A low-profile, small-size dual-frequency, dual-polarization wall-mounted antenna, characterized in that, include: A first dielectric substrate, a second dielectric substrate, and a third dielectric substrate are stacked together, and the lower surface of the first dielectric substrate is provided with a metal ground. A high-frequency antenna is positioned above the first dielectric substrate, passes through an opening in the central region of the second dielectric substrate, and is located in the middle of the third dielectric substrate; The low-frequency antenna includes a square rotating ring radiating patch disposed on the upper surface of a third dielectric substrate. The square rotating ring radiating patch is arranged around a high-frequency antenna so that the low-frequency antenna and the high-frequency antenna form a coaxial nested structure. The electromagnetic bandgap structure includes multiple metal patches disposed on the upper surface of a second dielectric substrate, and multiple copper pillars passing through the second dielectric substrate and electrically connecting the metal patches to a metal ground. The electromagnetic bandgap structure is located below the low-frequency antenna. A metal partition wall, erected on the first dielectric substrate and located between the radiating elements of the high-frequency antenna and the low-frequency antenna, is used to suppress spatial coupling. Two 1-to-2 differential power dividers are set on the upper surface of the first dielectric substrate and connected to a square rotating ring radiating patch through a power feed copper pillar to differentially feed the low-frequency antenna. The low-frequency antenna feed coaxial line has its outer conductor connected to the metal ground and its inner conductor connected to the input terminal of the 1-to-2 differential feed power divider. The high-frequency antenna feed coaxial line has its outer conductor connected to the metal ground of the first dielectric substrate, and its inner conductor connected to the feed structure of the high-frequency antenna.

2. The low-profile, small-size dual-frequency, dual-polarization wall-mounted antenna as described in claim 1, characterized in that: The copper pillars in the electromagnetic bandgap structure are welded or connected to the metal ground at their bottom ends and connected to the corresponding metal patches at their top ends; the metal patches are periodically arranged on the upper surface of the second dielectric substrate.

3. The low-profile, small-size dual-frequency, dual-polarization wall-mounted antenna as described in claim 1, characterized in that: The first dielectric substrate has a slot, and the bottom of the metal isolation wall is fixed in the slot. The metal isolation wall is a vertical metal wall surrounding the high-frequency antenna.

4. The low-profile, small-size dual-frequency, dual-polarization wall-mounted antenna as described in claim 1, characterized in that: The 1-to-2 differential power divider includes a jumper structure, and a metallized via is provided on the first dielectric board. The jumper is connected to the power divider network through the metallized via. The two 1-to-2 differential power dividers correspond to the two orthogonal polarization ports of the low-frequency antenna, respectively.

5. A low-profile, small-size dual-frequency, dual-polarization wall-mounted antenna as described in claim 1, characterized in that: The high-frequency antenna is an aluminum cast model with a Г-shaped feed structure on it. The inner conductor of the high-frequency antenna feed coaxial line is connected to the Г-shaped feed structure.

6. The low-profile, small-size dual-frequency, dual-polarization wall-mounted antenna as described in claim 1, characterized in that: The upper surface of the third dielectric plate is also provided with four square patches, each of which is connected to the metal ground through a corresponding copper pillar.

7. A low-profile, small-size dual-frequency, dual-polarized wall-mounted antenna as described in any one of claims 1 to 6, characterized in that: It also includes multiple nylon pillars, with non-metallized vias corresponding to the first, second, and third dielectric plates. The nylon pillars pass through the non-metallized vias and support and fix the relative distance between each dielectric plate.

8. A low-profile, small-size dual-frequency, dual-polarization wall-mounted antenna as described in claim 1, characterized in that: The low-frequency antenna operates in the frequency band of 0.88~0.96GHz, and the high-frequency antenna operates in the frequency band of 1.71~2.69GHz; the isolation between different frequency ports is greater than 25dB, and the isolation between the same frequency ports is greater than 22dB.

9. A low-profile, small-size dual-frequency, dual-polarization wall-mounted antenna as described in claim 1, characterized in that: The electromagnetic bandgap structure is used to change the phase of the low-frequency reflected wave so that the overall profile height of the antenna does not exceed 0.1 times the low-frequency wavelength.

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