A multi - frequency antenna for multi - network fusion deployment in urban underground utility tunnels

Abstract

The present invention relates to a multi-frequency antenna for multi-network integration deployment of urban underground integrated pipe corridors, including: a double-layer radiation unit, including a first electric dipole structure and a second electric dipole structure that are symmetrical to each other; an η-shaped feeding unit, which is arranged between the first electric dipole structure and the second electric dipole structure, and the bottom of the η-shaped feeding unit is connected to the inner conductor probe of the feeding coaxial connector in the double-layer radiation unit, for realizing coupled feeding of the double-layer radiation unit; a "凵"-shaped floor unit, which is arranged below the η-shaped feeding unit and the double-layer radiation unit, for reflecting the electromagnetic waves radiated by the double-layer radiation unit to form directional radiation, and at the same time connected with the double-layer radiation unit to form a magnetic dipole structure, which is complementary to the electromagnetic field radiated by the first to second electric dipole structures of the double-layer radiation unit in space, so as to improve the working bandwidth of the antenna and the symmetry of the radiation pattern. The present invention can be widely used in the field of electronic technology.

Description

Technical Field

[0001] The present invention belongs to the field of electronic technology, and relates to a multi-frequency antenna for multi-network integration deployment of urban underground comprehensive pipe corridors, and in particular to a directional multi-frequency antenna based on a magnetoelectric dipole structure. Background Art

[0002] A complex communication network needs to be built in the new digital underground utility corridor to support the realization of various services such as power Internet of Things data collection, smart mobile inspection, and real-time calls above and below the ground. It is necessary to select a variety of wireless communication systems that meet business needs from a variety of wireless technologies such as 4G, 5G, WiFi / WiFi6, NB-IoT, LoRa, ZigBee, Bluetooth, RFID, etc. for comprehensive networking. Therefore, the wireless communication system of the underground utility corridor will be a comprehensive communication network deployed with multi-network integration.

[0003] At present, the transmitting and receiving antennas of the wireless communication system in the underground integrated pipe gallery are generally deployed with whip antennas. The whip antenna is a monopole antenna and a narrowband omnidirectional radiating antenna. Even if it is designed to be broadband, it is difficult to adapt to the multi-band requirements of multi-network integration deployment. On the other hand, omnidirectional antennas are not suitable for use in pipe gallery scenarios, because the underground integrated pipe gallery environment is a tunnel scenario with four closed sides and two open ends. The propagation characteristics of wireless signals in the pipe gallery are significantly different from those of the ground system. The multiple reflections of wireless signals by the four walls of the pipe gallery and the scattering caused by the wiring racks, cables and other structures deployed inside the pipe gallery will form a significant multipath superposition effect. Therefore, the propagation characteristics of wireless signals in the pipe gallery will show a large-scale fading superimposed on a severe small-scale fading, resulting in the phenomenon of periodic weak coverage areas along the extension direction of the pipe gallery. Summary of the invention

[0004] In response to the needs of multi-network integration deployment in urban underground comprehensive pipeline corridors and the coverage requirements of special scenarios in the pipeline corridors, the purpose of the present invention is to provide a multi-frequency antenna for multi-network integration deployment in urban underground comprehensive pipeline corridors, which meets the needs of multiple systems sharing communication antennas in the pipeline corridor, simplifies deployment difficulty, and improves resource utilization. At the same time, the directional radiation characteristics of the antenna can also effectively reduce the coverage deterioration problem caused by reflections from the four walls of the pipeline corridor, and has important application value.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A multi-frequency antenna for multi-network integration deployment of urban underground integrated pipe corridors, comprising:

[0007] Double-layer radiation unit, η-shaped feeding unit and "凵"-shaped floor unit;

[0008] The double-layer radiation unit includes a first electric dipole structure and a second electric dipole structure which are symmetrical to each other, and are used to form resonance at a preset frequency to achieve a broadband operating frequency band;

[0009] The n-shaped feeding unit is arranged between the first electric dipole structure and the second electric dipole structure, and the bottom of the n-shaped feeding unit is connected to the inner conductor probe of the feeding coaxial connector in the double-layer radiating unit, so as to realize coupling feeding of the double-layer radiating unit;

[0010] The "凵"-shaped floor unit is arranged below the η-shaped feeding unit and the double-layer radiating unit. On the one hand, it is used to reflect the electromagnetic waves radiated by the double-layer radiating unit to form directional radiation. On the other hand, it is used to connect with the double-layer radiating unit to form a 凵-shaped conductive groove to constitute a magnetic dipole structure, which complements the electromagnetic field radiated by the first to second electric dipole structures of the double-layer radiating unit in space to improve the antenna working bandwidth and the symmetry of the radiation pattern.

[0011] Further, the first electric dipole structure and the second electric dipole structure are the same, and both include an upper electric dipole and a lower electric dipole;

[0012] The upper electric dipole and the lower electric dipole are arranged in parallel, and one end of the upper electric dipole and the lower electric dipole are fixedly connected to the "凵"-shaped floor unit via a vertical connecting wall structure; the other end of the upper electric dipole and the lower electric dipole are fixedly connected to the "凵"-shaped floor unit via a non-metallic support column to form resonance at a preset frequency and realize a broadband operating frequency band.

[0013] Furthermore, the upper electric dipole adopts a symmetrical "E"-shaped structure, which includes a first intermediate radiation array and two first edge radiation arrays located on both sides of the first intermediate radiation array, the length of the first intermediate radiation array is smaller than the length of the two first edge radiation arrays, and one end of each radiation array is connected and fixed to the "凵"-shaped floor unit via the vertical connecting wall structure, and the other end of each radiation array is fixed to the "凵"-shaped floor unit via a non-metallic support column.

[0014] Furthermore, the lower electric dipole adopts a symmetrical "mountain" shaped structure, which includes a second intermediate radiation array and two second edge radiation arrays located on both sides of the second intermediate radiation array, and the length of the second intermediate radiation array is greater than the length of the two second edge radiation arrays. After one end of each radiation array is connected, it is fixed on the "凵" shaped floor unit via the vertical connecting wall structure, and the other end of each radiation array is fixed on the "凵" shaped floor unit via a non-metallic support column.

[0015] Furthermore, the second intermediate radiation array is composed of a rectangular radiation array and a trapezoidal radiation array connected to each other, and the length of the rectangular radiation array is the same as that of the second edge radiation array.

[0016] Further, the n-shaped feeding unit comprises a rectangular structure metal sheet, a first trapezoidal structure metal sheet and a second trapezoidal structure metal sheet;

[0017] The rectangular structure metal sheet is fixedly arranged at a preset position of the "凵"-shaped floor unit by a non-metallic support column, the first trapezoidal structure metal sheet and the second trapezoidal structure metal sheet are vertically arranged at both ends of the rectangular structure metal sheet and extend downward, and the upper bases of the first trapezoidal structure metal sheet and the second trapezoidal structure metal sheet are respectively connected to the two sides of the rectangular structure metal sheet to form an η-shaped structure;

[0018] The bottom of the first trapezoidal structure metal sheet is connected to the inner conductor probe of the coaxial feeding connector, and the distance between the connection point between the first trapezoidal structure metal sheet and the inner conductor probe and the "凵"-shaped floor unit is a preset first height;

[0019] The bottom of the second trapezoidal structure metal sheet is suspended in the air, and the distance between the bottom of the second trapezoidal structure metal sheet and the "凵"-shaped floor unit is a preset second height.

[0020] Furthermore, the first preset height is 1 mm.

[0021] Furthermore, the upper bases of the first trapezoidal structure metal sheet and the second trapezoidal structure metal sheet are the same length as the short sides of the rectangular structure metal sheet; the lower base of the first trapezoidal structure metal sheet is shorter than the lower base of the second trapezoidal structure metal sheet.

[0022] Furthermore, the "凵"-shaped floor unit includes a rectangular bottom plate and two side plates, and the two side plates are arranged on both sides of the rectangular bottom plate to form a "凵"-shaped metal floor.

[0023] Furthermore, the two side panels have the same size.

[0024] The present invention adopts the above technical solution, which has the following advantages:

[0025] 1. The multi-frequency antenna designed by the present invention can be designed in different sizes according to actual needs to meet the coverage of different working frequency bands, and can support the integrated networking deployment of multiple communication systems from 2G to 5G mobile communication systems, WiFi, Lora, Zigbee, etc. It improves resource utilization and reduces the complexity of network deployment in the pipe gallery.

[0026] 2. The multi - frequency antenna designed by the present invention exhibits a directional radiation characteristic in each operating frequency band. Deploying this multi - frequency antenna in the utility tunnel can effectively alleviate the periodic weak coverage caused by the multipath effect in the area near the antenna and improve the wireless coverage in a relatively long area of the utility tunnel.

[0027] The antenna unit structure designed by the present invention is simple. Only a feeding structure and a double - layer radiation structure are used to form a magnetoelectric dipole antenna, which has the characteristics of four operating frequency bands and supports the applications of various communication systems that may be deployed in the utility tunnel. Therefore, the present invention can be widely applied in the field of electronic technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0029] Figure 1 is a three - dimensional structure diagram of the multi - frequency antenna for multi - network fusion deployment in the urban underground utility tunnel provided by the embodiment of the present invention;

[0030] Figure 2 is a top view of the multi - frequency antenna without adding a non - metallic support structure provided by the embodiment of the present invention;

[0031] Figure 3 is a front view of the multi - frequency antenna without adding a non - metallic support structure provided by the embodiment of the present invention;

[0032] Figure 4 is a side view of the multi - frequency antenna without adding a non - metallic support structure provided by the embodiment of the present invention;

[0033] Figure 5 is a reflection loss diagram provided by the embodiment of the present invention;

[0034] Figure 6 is the radiation pattern of Phi = 0° and Phi = 90° at 780 MHz in the Lora, 2G, and NB - IoT frequency bands provided by the embodiment of the present invention;

[0035] Figure 7 is the radiation pattern of Phi = 0° and Phi = 90° at 1800 MHz in the 2G and 4G frequency bands provided by the embodiment of the present invention;

[0036] Figure 8 is the radiation pattern of Phi = 0° and Phi = 90° at 2400 MHz in the 4G, 5G, WiFi and other frequency bands provided by the embodiment of the present invention;

[0037] Figure 9This is a directional diagram of Phi=0° and Phi=90° at the WiFi frequency band 5800 MHz provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0040] In some embodiments of the present invention, a multi-frequency antenna for multi-network integration deployment of urban underground integrated pipe corridors is provided, including an η-shaped feeding unit, a double-layer radiating unit and a "凵"-shaped floor unit. The double-layer radiating unit includes a symmetrically arranged first electric dipole structure and a second electric dipole structure, which are used to form resonance at a preset frequency to achieve a broadband working frequency band; the η-shaped feeding unit is arranged between the first electric dipole structure and the second electric dipole structure, and the bottom of the η-shaped feeding unit is connected to the inner conductor probe of the feeding coaxial connector in the double-layer radiating unit, which is used to achieve coupled feeding of the double-layer radiating unit; the "凵"-shaped floor unit is arranged below the η-shaped feeding unit and the double-layer radiating unit, on the one hand, for reflecting the electromagnetic waves radiated by the double-layer radiating unit to form directional radiation, and on the other hand, for connecting with the inner wall of the double-layer radiating unit to form a 凵-shaped conductive groove, forming a magnetic dipole structure, and the electromagnetic field radiated by the first to second electric dipole structures of the double-layer radiating unit is complementary in space, so as to improve the antenna working bandwidth and the symmetry of the radiation pattern. The present invention has a multi-band broadband working effect, can support the integrated deployment of multiple communication systems, realize resource reuse, improve resource utilization, and reduce the complexity of network deployment in the tunnel. On the other hand, the antenna designed by the present invention has good directivity. When deployed in the tunnel, it can achieve wireless coverage of the space where the tunnel is heading, reduce the reflection of the signal by the four walls of the tunnel, and can effectively alleviate the periodic weak coverage phenomenon caused by the multipath effect in the tunnel, and improve the wireless coverage in the longer area of ​​the tunnel. The present invention can be widely used in the field of electronic technology.

[0041] Example 1

[0042] like Figure 1 As shown, this embodiment provides a multi-frequency antenna for multi-network integration deployment of urban underground comprehensive pipeline corridors, which includes: a double-layer radiation unit 1, an η-shaped feeding unit 2 and a "凵"-shaped floor unit 3. Among them, the double-layer radiation unit 1 includes a symmetrically arranged first electric dipole structure 11 and a second electric dipole structure 12, which are used to form resonance at a preset frequency to achieve a broadband working frequency band; the η-shaped feeding unit 2 is arranged between the first electric dipole structure 11 and the second electric dipole structure 12, and the bottom of the η-shaped feeding unit 2 is connected to the inner conductor probe of the feeding coaxial connector in the double-layer radiation unit 1, which is used to realize the coupling feeding of the double-layer radiation unit 1; the "凵"-shaped floor unit 3 is arranged below the η-shaped feeding unit 2 and the double-layer radiation unit 1, on the one hand, it is used to reflect the electromagnetic waves radiated by the double-layer radiation unit 1 to form directional radiation, and on the other hand, it is used to connect with the inner wall of the double-layer radiation unit 1 to form a 凵-shaped conductive groove to form a magnetic dipole structure, which is complementary to the electromagnetic field radiated by the first to second electric dipole structures of the double-layer radiation unit 1 in space, thereby improving the working bandwidth of the antenna and the symmetry of the radiation pattern.

[0043] In a preferred embodiment, Figure 2 As shown, in the double-layer radiation unit 1, the first electric dipole structure 11 and the second electric dipole 12 have the same structure, both including an upper electric dipole 111 and a lower electric dipole 112, wherein the upper electric dipole 111 and the lower electric dipole 112 are arranged in parallel, and one end of the upper electric dipole 111 and the lower electric dipole 112 are fixedly connected to the "凵"-shaped floor unit 3 via a vertical connecting wall structure 113; the other end of the upper electric dipole 111 and the lower electric dipole 112 are fixedly connected to the "凵"-shaped floor unit 3 via a non-metallic support column 114, so as to form resonance at a preset frequency and realize a broadband working frequency band.

[0044] In a preferred embodiment, the upper electric dipole 111 adopts a symmetrical "E"-shaped structure, which includes a first intermediate radiating array and two first edge radiating arrays located on both sides of the first intermediate radiating array. The length of the first intermediate radiating array is smaller than the length of the two first edge radiating arrays. After one end of each radiating array is connected, it is fixed on the "凵"-shaped floor unit via a vertical connecting wall structure, and the other end of each radiating array is fixed to the "凵"-shaped floor unit via a non-metallic support column; the first intermediate position radiating vibrator and the two first edge radiating vibrators are respectively used to form resonances at the low-frequency and high-frequency positions of 1.70GHz-1.96GHz, forming a broadband working frequency band.

[0045] In a preferred embodiment, the lower layer of electric dipoles 112 adopts a symmetric "mountain" - shaped structure, which includes a second intermediate radiation element and two second edge radiation elements located on both sides of the second intermediate radiation element. The length of the second intermediate radiation element is greater than the lengths of the two second edge radiation elements. One end of each radiation element is connected and then fixed to the "U" - shaped floor unit through a vertical connection wall structure, and the other end of each radiation element is fixed to the "U" - shaped floor unit through a non - metallic support column respectively. The second intermediate radiation element and the two second edge radiation elements are respectively used to achieve resonance in the 800 - MHz frequency band and the 1800 - MHz frequency band, realizing two operating frequency bands.

[0046] In a preferred embodiment, the second intermediate radiation element is composed of a rectangular radiation element and a trapezoidal radiation element connected to each other, and the length of the rectangular radiation element is the same as the length of the second edge radiation element.

[0047] In a preferred embodiment, as Figure 3 、 Figure 4 shown, the η - shaped feeding unit 2 includes a rectangular - structure metal sheet 21, a first trapezoidal - structure metal sheet 22, and a second trapezoidal - structure metal sheet 23. Among them, the rectangular - structure metal sheet 21 is fixedly arranged at a preset position of the "U" - shaped floor unit 3 through a non - metallic support column 24. The first trapezoidal - structure metal sheet 22 and the second trapezoidal - structure metal sheet 23 are vertically arranged at both ends of the rectangular - structure metal sheet 21 and extend downward, and the upper bases of the first trapezoidal - structure metal sheet 22 and the second trapezoidal - structure metal sheet 23 are respectively connected to both sides of the rectangular - structure metal sheet 21 to form an η - shaped structure. The bottom of the first trapezoidal - structure metal sheet 22 is connected to the inner - conductor probe of the coaxial feeding connector, and the distance between the connection point of the first trapezoidal - structure metal sheet 22 and the inner - conductor probe and the "U" - shaped floor unit 3 is a preset first height, for example, it can be 1 mm. The bottom of the second trapezoidal - structure metal sheet 23 is suspended, and the distance between it and the "U" - shaped floor unit 3 is a preset second height.

[0048] In a preferred embodiment, in the η - shaped feeding unit, the upper bottom edges of the first trapezoidal - structure metal sheet 22 and the second trapezoidal - structure metal sheet 23 are the same length as the short side of the rectangular - structure metal sheet 21. The length of the lower bottom edge of the first trapezoidal - structure metal sheet 22 is less than the length of the lower bottom edge of the second trapezoidal - structure metal sheet 23. The top rectangular - structure metal sheet 21 of the η - shaped feeding unit 2 is used to achieve resonance in the 5.8 - GHz frequency band, realizing an operating frequency band at 5.8 GHz.

[0049] In a preferred embodiment, the "U" - shaped floor unit 3 includes a rectangular bottom plate 31 and two side plates 32. The two side plates 32 are arranged on both sides of the rectangular bottom plate 31 to form a "U" - shaped metal ground.

[0050] In a preferred embodiment, the two side plates 32 of the "U" - shaped floor unit 3 have the same size.

[0051] Example 2

[0052] This embodiment uses the radio frequency full-wave simulation software Ansoft HFSS to simulate the multi-frequency antenna.

[0053] Among them, in the η-shaped feeding unit, the length and width of the rectangular structure metal sheet are recorded as L2 and W1 respectively; the upper bottom length of the first trapezoidal structure metal sheet is W1, the lower bottom length is W2, and the height is H2; the upper bottom length of the second trapezoidal structure metal sheet is W1, and the lower bottom length is W3; the distance between the bottom of the second trapezoidal structure metal sheet and the "凵"-shaped floor unit is H4; the distance between the η-shaped feeding unit and the double-layer radiation unit is g1;

[0054] In the double-layer radiation unit, the distances between the upper electric dipole and the lower electric dipole and the "凵"-shaped floor unit are H3 and H1 respectively; the length of the first intermediate radiation array is L6 and the width is W7; the length of the first edge radiation array is L7 and the width is W8; the spacing between the first intermediate radiation array and the two first edge radiation arrays is g4; the length of the connection end of the first intermediate radiation array and the first edge radiation array is g2; the first intermediate radiation vibrator and the two first edge radiation vibrators are used to form resonances at the low-frequency and high-frequency positions of 1.70GHz-1.96GHz respectively. A broadband working frequency band is formed; in the second intermediate radiation array, the length of the rectangular radiation array is L3, the width is W5, the upper base of the trapezoidal radiation array is W3, the lower base is W6, and the height is L4; the length of the second edge radiation array is L3, and the width is W4; the interval between the second intermediate radiation array and the two second edge radiation arrays is g3; the length of the connection end between the second intermediate radiation array and the second edge radiation array is L5; the second intermediate radiation vibrator and the two second edge radiation vibrators are used to realize the resonance of the 800MHz frequency band and the 1800MHz frequency band respectively, so as to realize two working frequency bands;

[0055] In the "凵"-shaped floor unit, the length of the rectangular bottom plate is Lg and the width is Wg; the length of the two side panels is Lg and the height is H5.

[0056] The specific structural parameters are shown in Table 1 below.

[0057] Table 1 Antenna structure dimension values

[0058]

[0059]

[0060] like Figure 5As shown, the multi-band antenna provided in this embodiment can cover four operating frequency bands: 0.72 GHz - 0.96 GHz (Lora band and 2G band), 1.70 GHz - 1.96 GHz (2G band and 4G band), 2.05 GHz - 2.76 GHz, (4G, 5G, WiFi, Zigbee, etc. bands), 5.76 GHz - 6.12 GHz (WiFi band). It can support multiple communication networks such as NB-IoT, ZigBee, Bluetooth, RFID, and WiFi to share the same antenna, improving resource utilization and reducing the complexity of network deployment in the pipe gallery.

[0061] As Figures 6 to 9 shown, the radiation pattern diagrams of the multi-band antenna at four frequencies of 780 MHz in the Lora, 2G, and NB-IoT bands, 1800 MHz in the 2G and 4G bands, 2400 MHz in the 4G, 5G, WiFi, etc. bands, and 5800 MHz in the WiFi band are respectively given. It can be seen from the figure that the antenna has good directivity and good symmetry at these four frequencies.

[0062] The above embodiments are only used to illustrate the present invention. The structures, connection methods, manufacturing processes, etc. of each component can all be changed. Any equivalent transformation and improvement based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A multi - frequency antenna for multi - network integrated deployment in urban underground utility tunnels, characterized in that, include: Double-layer radiation unit, η-shaped feeding unit and "凵"-shaped floor unit; The double-layer radiation unit includes a first electric dipole structure and a second electric dipole structure which are symmetrical to each other, and are used to form resonance at a preset frequency to achieve a broadband operating frequency band; The n-shaped feeding unit is arranged between the first electric dipole structure and the second electric dipole structure, and the bottom of the n-shaped feeding unit is connected to the inner conductor probe of the feeding coaxial connector in the double-layer radiating unit, so as to realize coupling feeding of the double-layer radiating unit; The "凵"-shaped floor unit is arranged below the η-shaped feeding unit and the double-layer radiating unit, and is used to reflect the electromagnetic waves radiated by the double-layer radiating unit to form directional radiation on the one hand, and is used to connect with the double-layer radiating unit to form a 凵-shaped conductive slot to form a magnetic dipole structure, which is complementary to the electromagnetic fields radiated by the first to second electric dipole structures of the double-layer radiating unit in space, so as to improve the working bandwidth of the antenna and the symmetry of the radiation pattern; The first electric dipole structure and the second electric dipole structure are the same, both comprising an upper electric dipole and a lower electric dipole; the upper electric dipole and the lower electric dipole are arranged in parallel, and one end of the upper electric dipole and the lower electric dipole is fixedly connected to the "凵"-shaped floor unit via a vertical connecting wall structure; one end of the upper electric dipole and the lower electric dipole is fixedly connected to the "凵"-shaped floor unit via a non-metallic support column, and the other end is used to form resonance at a preset frequency to achieve a broadband working frequency band; The upper electric dipole adopts a symmetrical "E"-shaped structure, which includes a first middle radiating array and two first edge radiating arrays located on both sides of the first middle radiating array, the length of the first middle radiating array is less than the length of the two first edge radiating arrays, one end of each radiating array is connected and fixed to the "凵"-shaped floor unit via the vertical connecting wall structure, and the other end of each radiating array is fixed to the "凵"-shaped floor unit via a non-metallic support column; The lower electric dipole adopts a symmetrical "mountain" shaped structure, which includes a second intermediate radiation array and two second edge radiation arrays located on both sides of the second intermediate radiation array, and the length of the second intermediate radiation array is greater than the length of the two second edge radiation arrays. After one end of each radiation array is connected, it is fixed on the "凵" shaped floor unit through the vertical connecting wall structure, and the other end of each radiation array is fixed on the "凵" shaped floor unit through a non-metallic support column; The second intermediate radiation array is composed of a rectangular radiation array and a trapezoidal radiation array connected to each other, and the length of the rectangular radiation array is the same as that of the second edge radiation array.

2. The multi - frequency antenna for multi - network integrated deployment in urban underground utility tunnels according to claim 1, wherein, The n-shaped feeding unit comprises a rectangular structure metal sheet, a first trapezoidal structure metal sheet and a second trapezoidal structure metal sheet; The rectangular metal sheet is fixedly arranged at a preset position of the "U"-shaped floor unit through a non-metal support column. The first trapezoidal metal sheet and the second trapezoidal metal sheet are vertically arranged at both ends of the rectangular metal sheet and extend downward. The upper bases of the first trapezoidal metal sheet and the second trapezoidal metal sheet are respectively connected to both sides of the rectangular metal sheet to form an η-shaped structure; The bottom of the first trapezoidal metal sheet is connected to the inner conductor probe of the coaxial feed joint, and the distance between the connection of the first trapezoidal metal sheet and the inner conductor probe and the "U"-shaped floor unit is a preset first height; The bottom of the second trapezoidal metal sheet is suspended, and the distance between the bottom of the second trapezoidal metal sheet and the "U"-shaped floor unit is a preset second height.

3. The multi-frequency antenna for multi-network integrated deployment in urban underground utility tunnels according to claim 2, wherein The preset first height is 1 mm.

4. The multi-frequency antenna for multi-network integrated deployment in urban underground utility tunnels as claimed in claim 2, wherein The upper bottom sides of the first trapezoidal metal sheet and the second trapezoidal metal sheet are the same length as the short side of the rectangular metal sheet; the length of the lower bottom side of the first trapezoidal metal sheet is less than the length of the lower bottom side of the second trapezoidal metal sheet.

5. The multi - frequency antenna for multi - network integrated deployment in urban underground utility tunnels according to claim 1, wherein The "U"-shaped floor unit includes a rectangular bottom plate and two side plates. The two side plates are arranged on both sides of the rectangular bottom plate to form a "U"-shaped metal ground.

6. The multi - frequency antenna for multi - network integrated deployment in urban underground utility tunnels according to claim 5, characterized in that, The two side plates have the same size.

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