A broadband omnidirectional antenna unit and a broadband omnidirectional high-gain antenna

Abstract

The present invention discloses a broadband omnidirectional antenna unit and a broadband omnidirectional high-gain antenna. A broadband omnidirectional antenna unit is composed of a supporting structure, a radiating structure, a choke, and a passive coupling structure. A channel for the antenna feeding coaxial line is provided in the middle of the supporting structure; the radiating structure is composed of an upper radiating arm, a lower radiating arm, and a short-circuit block. The upper radiating arm and the lower radiating arm are in the form of a biconical antenna, and the short-circuit block is a fan-ring cylindrical structure and is eccentrically arranged; the passive coupling structure is directly above the radiating structure. The broadband omnidirectional high-gain antenna of the present invention is composed of four broadband omnidirectional antenna units, and there is a 90° orientation angle difference between two adjacent broadband omnidirectional antenna units around the antenna axis. Simulation results show that the present invention has the advantages of simple feeding, higher gain, and wider bandwidth.

Description

Technical Field

[0001] The present invention relates to a broadband omnidirectional high-gain antenna, and in particular to a broadband omnidirectional high-gain antenna applied to a vehicle-mounted communication system, which mainly solves the problems of low gain and narrow bandwidth of traditional omnidirectional antennas. Background Art

[0002] With the continuous development of wireless communication technology, people are placing increasingly higher demands on antennas used in wireless communications. Omnidirectional, high-gain antennas, due to their wide coverage and strong anti-interference capabilities, are now widely used in various vehicle-mounted communications and base station communication systems. There are currently two approaches to achieving omnidirectional, high-gain antennas: one is to leverage the inherent omnidirectionality of certain antennas, increasing antenna gain by forming an array in directions perpendicular to the omnidirectional plane, thereby achieving a high-gain omnidirectional pattern. The other is to use high-gain directional antennas as array antenna elements to form a planar circular array, where the complementary patterns of the individual antenna elements form a high-gain omnidirectional pattern.

[0003] Xidian University disclosed a broadband omnidirectional high-gain antenna array in its patent application document "Broadband Omnidirectional High-Gain Linear Array Antenna" (application number CN202210730483.5, application publication number CN 114899619 A). The antenna divides the antenna array into four independent linear array antennas, and arranges them in a parallel and vertical manner, fixed on the base of a one-to-four power divider. Each linear array antenna uses four directional antennas as units to form a four-element linear array, thereby obtaining high gain. The four linear array antennas are then arranged in a ring shape and fixed on the base of the one-to-four power divider to obtain an omnidirectional radiation pattern. The antenna has a wide bandwidth, good omnidirectionality, a simple structure and is easy to manufacture. However, the antenna still has the disadvantage that its antenna bandwidth still cannot meet the requirements for use scenarios with higher channel capacity requirements.

[0004] The 724th Research Institute of China Shipbuilding Industry Corporation has applied for a method for realizing a high-gain omnidirectional biconical antenna array in its patent document "A Method for Realizing a High-Gain Omnidirectional Biconical Antenna Array" (application number CN202110060816.3, application publication number CN 112886279 A). This method uses a coaxial nested feeding structure to realize parallel feeding of the omnidirectional antenna array, overcomes the influence of the feeding device on the antenna pattern, avoids the "frequency sweep" phenomenon caused by series feeding, and improves the out-of-roundness of the antenna under conventional parallel feeding. However, the method still has the disadvantage that once multiple units are used to form an array, multiple nestings will increase the volume of the antenna feeding structure and make the structure complex, while squeezing the space of the radiator and affecting the antenna's performance such as the pattern.

[0005] In summary, while existing technologies can achieve a certain degree of broadband and high gain, they still cannot meet the needs of scenarios with higher channel capacity requirements. Furthermore, there is room for improvement in the parallel feeding method of high-gain omnidirectional biconical antenna arrays. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a broadband omnidirectional high-gain antenna with simplified feeding, higher gain, and wider bandwidth. Based on this broadband omnidirectional antenna unit, a broadband omnidirectional high-gain antenna for use in vehicle-mounted communication systems is also proposed. Compared with traditional omnidirectional antennas, this omnidirectional antenna offers advantages such as simplified feeding, higher gain, and wider bandwidth.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A broadband omnidirectional antenna unit (1) is composed of a supporting structure (2), a radiating structure (3), a choke (4), a passive coupling structure (5) and a feeding interface (6); the supporting structure (2) passes through the central circular hole of the radiating structure (3), the choke (4) and the passive coupling structure (5) and a channel for the antenna feeding coaxial line is provided in the middle; the radiating structure (3) is composed of an upper radiating arm (7), a lower radiating arm (8) and a short-circuit block (9); the upper radiating arm (7) and the lower radiating arm (8) are formed in the form of a biconical antenna to widen the antenna standing wave bandwidth; the short-circuit block (9) is a fan-ring cylindrical structure and is arranged at a position deviated from the central axis; the passive coupling structure (5) is a bowl-shaped structure and is arranged directly above the radiating structure (3); the feeding interface (6) is arranged on the lower radiating arm (8), and the feeding interface (6) is deviated from the central axis and in the opposite direction to the deviation of the short-circuit block (9).

[0009] The choke (4) is located below the lower radiation arm (8), thereby improving the isolation between antenna units; the passive coupling structure (5) is located above the upper radiation arm (7), thereby introducing a new resonance point in a coupling manner, thereby improving the working bandwidth of the antenna.

[0010] The broadband omnidirectional antenna unit (1) is provided with a short-circuit block (9) disposed between an upper radiating arm (7) and a lower radiating arm (8) and at a position deviated from the central axis, and a feed interface (6) is disposed on a side of the lower radiating arm (8) close to the upper radiating arm (7), and the feed interface (6) extends from the bottom to the top of the lower radiating arm (8). The position of the feed interface (6) deviates from the central axis; the position of the short-circuit block (9) deviates from the central axis, and the direction in which the short-circuit block (9) deviates from the center is opposite to the direction in which the feed interface (6) deviates from the center, thereby improving the symmetry of the radiation pattern.

[0011] In the broadband omnidirectional antenna unit (1), the short-circuit block (9) deviates from the center of the antenna axis by a distance R1, and the feed interface (6) deviates from the center of the antenna axis in a direction opposite to that of the short-circuit block (9), and the deviation distance is R2.

[0012] The distance R1 of the short-circuit block (9) from the center is 23 to 33 mm; the distance R2 of the feed interface (6) from the center is 26 to 36 mm. The short-circuit block (9) is in the shape of a fan-ring column. The lower end of the lower radiation arm (8) has four protruding steps, and through holes are provided on the steps for installing the short-circuit block (9). The opposite side has a mounting hole for the feed interface (6) of the antenna unit.

[0013] The broadband omnidirectional antenna unit (1) is provided with a waist-shaped hole on the side wall of the lower end of the supporting structure (2), and the direction facing the waist-shaped hole is consistent with the direction in which the feeding interface (6) deviates from the center of the antenna axis, so as to realize the connection between the feeding coaxial line and the feeding interface (6); the lower radiating arm (8), the upper radiating arm (7), the choke (4) and the passive coupling structure (5) are all provided with weight-reducing holes for reducing the weight of the antenna.

[0014] The broadband omnidirectional antenna unit (1) has an upper radiating arm (7) located directly above the lower radiating arm (8) and a distance H2 from the lower radiating arm (8); the upper radiating arm (7) is not connected to the supporting structure (2), but is connected to the lower radiating arm (8) via a short-circuit block (9) and a feed interface (6). The upper radiating arm (7) is located directly above the lower radiating arm (8) at a distance H2 of 5 to 8 mm.

[0015] The broadband omnidirectional antenna unit (1) has a choke (4) which is a circular thin plate. The choke (4) is connected to the support structure (2) through a screw hole provided on the support structure (2). At the same time, the choke (4) is connected to the lower radiating arm (8) through a through hole on a step at the lower end of the lower radiating arm (8). The choke (4) is located directly below the lower radiating arm (8) and the distance from the lower radiating arm (8) is H1. The choke (4) is located directly below the lower radiating arm (8) at H1, and H1 is 3 to 6 mm. Two circles of weight-reducing holes are provided on the choke (4), and each circle of weight-reducing holes has 12 holes arranged evenly in a circular pattern. The two circles of weight-reducing holes are aligned.

[0016] The broadband omnidirectional antenna unit (1) has a passive coupling structure (5) that is a bowl-shaped structure. The passive coupling structure (5) is located at a position H3 directly above the upper radiation arm (7). The distance H3 between the passive coupling structure (5) and the upper radiation arm (7) is 27 to 35 mm.

[0017] A broadband omnidirectional high-gain antenna for use in an on-vehicle communication system comprises four identical broadband omnidirectional antenna units (1). The four broadband omnidirectional antenna units (1) are used to form an array, and two adjacent broadband omnidirectional antenna units (1) have a 90° orientation angle difference around the antenna axis. The antenna as a whole adopts an all-metal structure, and the support structure (2), lower radiation arm (8), short-circuit block (9), upper radiation arm (7), choke (4) and passive coupling structure (5) are all made of the same metal material.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] First, the present invention adopts a hollow circular cylindrical metal as the support structure of the antenna. By arranging the feeding coaxial line in the supporting structure, the influence of the feeding structure on the antenna radiation pattern is avoided. The feeding is achieved by leading the feeding coaxial line out from the waist-shaped hole on the side wall of the supporting structure, which solves the problem of difficult parallel feeding of the high-gain omnidirectional biconical antenna array and has the advantage of simple feeding.

[0020] Secondly, the present invention uses a biconical antenna as an antenna unit to expand the standing wave bandwidth of the antenna, and adopts a passive coupling structure to introduce a new resonance point for the antenna to further expand the standing wave bandwidth of the antenna. This makes the antenna of the present invention have a wider standing wave bandwidth.

[0021] Third, the present invention mitigates the pattern degradation caused by eccentric feeder alignment through two measures: first, aligning adjacent antenna elements 90° apart; and second, providing a short-circuit block in the opposite direction of the feeder offset. This results in the antenna having very low horizontal out-of-roundness and a wide pattern bandwidth.

[0022] Fourth, the present invention improves the antenna's omnidirectional radiation gain by forming a four-element array in the vertical direction. Passive coupling branches and chokes are used to improve isolation between antenna elements, avoiding the gain reduction caused by hesitant coupling between antenna elements. This results in the antenna having higher radiation gain.

[0023] Fifth, the present invention uses a metal antenna structure as the antenna element, rather than an antenna printed on a dielectric substrate, which increases the antenna's power capacity. Because the breakdown voltage of air is much higher than that of a dielectric substrate, the present invention's power capacity exceeds that of traditional omnidirectional antennas.

[0024] Simulation results show that the present invention has the advantages of simple feeding, higher gain, and wider bandwidth. The -10dB relative bandwidth of the present invention is 65.37%. In the entire frequency band, the maximum gain in the horizontal plane is greater than 4.24dBi, the maximum value is 8.27dBi, and the out-of-roundness is less than 1.59dB. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Shown is the overall structural diagram of the present invention;

[0026] Figure 2 is an exploded view of the antenna unit of the present invention;

[0027] FIG3( a ) is a schematic diagram of the main structural dimensions of the antenna unit of the present invention;

[0028] FIG3( b ) is a layout diagram of the short-circuit block and feed interface of the antenna unit of the present invention;

[0029] Figure 4 1 is a simulation result diagram of the active reflection coefficient of the feed port of the antenna unit of the present invention;

[0030] Figure 5 This is a simulation result diagram of the maximum gain of the azimuth plane vertical polarization varying with frequency according to the present invention;

[0031] Figure 6 This is a simulation result diagram of the variation of the azimuth plane vertical polarization non-circularity with frequency according to the present invention. DETAILED DESCRIPTION

[0032] In order to make the technical concept and advantages of the invention more clearly understood, the technical solution of the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the following embodiments are only used to explain and illustrate the preferred embodiments of the present invention and should not constitute a limitation on the scope of protection claimed in the patent application of the present invention.

[0033] Example 1

[0034] The following further describes the embodiments and technical effects of the present invention with reference to the accompanying drawings:

[0035] Reference Figure 1 、 Figure 2 3(a) and 3(b), the present invention discloses a broadband omnidirectional high-gain antenna for use in a vehicle-mounted communication system, which is composed of four broadband omnidirectional antenna units 1. Each broadband omnidirectional antenna unit 1 includes a support structure 2, a lower radiating arm 8, a short-circuit block 9, an upper radiating arm 7, a choke 4, a passive coupling structure 5, and a feeding interface 6.

[0036] The support structure 2 is an annular cylindrical structure with four rows of screw holes on its outer surface, with four screw holes in each row evenly distributed. A waist-shaped hole is provided near the lower end of the support structure 2 to ensure that the antenna feed cable is connected to the antenna feed interface 6. The support structure 2 passes through the central circular hole of the choke 4, the lower radiating arm 8, the upper radiating arm 7, and the passive coupling structure 5 and is connected and fixed to the choke 4, the lower radiating arm 8, and the passive coupling structure 5. The hollow space in the middle of the support structure 2 provides a channel for the feed cable.

[0037] The lower radiating arm 8 has a bowl-shaped structure, with two rows of waist-shaped holes evenly distributed in a circular pattern on the side wall. There are 20 waist-shaped holes in each row, and the two rows of waist-shaped holes are staggered with each other, achieving the effect of reducing weight without affecting the performance of the antenna; the lower end of the lower radiating arm 8 has four protruding steps, and through holes are provided on the steps for connecting to the choke 4; the upper end of the lower radiating arm 8 has a threaded hole for fixing the short-circuit block 9 on the side deviating from the axis, and the opposite side has a mounting hole for the feed interface 6 of the antenna unit.

[0038] The short-circuit block 9 is fan-ring cylindrical, and the feed interface 6 is a two-hole flange SMA type electrical connector; the short-circuit block 9 is above the lower radiating arm 8, and the feed interface 6 extends from the bottom of the lower radiating arm 8 to the top; the short-circuit block 9 deviates from the antenna axis by a distance of R1, and the feed interface 6 deviates from the antenna axis in a direction opposite to that of the short-circuit block 9 by a distance of R2.

[0039] The upper radiating arm 7 is a bowl-shaped structure, and its side walls have the same configuration as the side walls of the lower radiating arm 8; the upper radiating arm 7 is located directly above the lower radiating arm 8, and the distance from the lower radiating arm 8 is H2; the upper radiating arm 7 is not connected to the support structure 2, but is connected to the lower radiating arm 8 through the short-circuit block 9 and the feed interface 6.

[0040] The choke 4 is a circular thin sheet with two circles of weight-reducing holes on it. Each circle of weight-reducing holes has 12 holes evenly arranged in a circle, and the two circles of weight-reducing holes are aligned. The choke 4 is located directly below the lower radiating arm 8, and the distance from the lower radiating arm 8 is H1. The choke 4 is connected to the support structure 2 through the screw holes provided on the support structure 2. At the same time, the choke 4 is connected to the lower radiating arm 8 through the through hole on the step at the lower end of the lower radiating arm 8.

[0041] The passive coupling structure 5 is a bowl-shaped structure, and its side walls have the same configuration as the side walls of the lower radiating arm 8; the passive coupling structure 5 is located directly above the upper radiating arm 7, and the distance from the upper radiating arm 7 is H3; the passive coupling structure 5 is connected to the support structure 2 through screw holes provided on the support structure 2.

[0042] The antenna as a whole adopts an all-metal structure. When four broadband omnidirectional antenna units 1 are used to form an array, two adjacent broadband omnidirectional antenna units 1 have a direction angle difference of 90° rotated around the antenna axis.

[0043] 3( a ) and 3 ( b ), in this embodiment, it is set but not limited to H1 = 4.00 mm, H2 = 6.00 mm, H3 = 30.00 mm, R1 = 29.00 mm, and R2 = 30.00 mm.

[0044] The effect of this embodiment can be further illustrated by the following simulation experiment:

[0045] Using the High Frequency Structure Simulator simulation software, use Figure 1 The model shown in the figure is simulated and the results are as follows Figures 4 to 6 The simulation results are shown.

[0046] Figure 4 The figure is a simulation result diagram of the active standing wave ratio of the feed port of the antenna unit of the present invention. Figure 4 The horizontal axis represents the frequency, and the vertical axis represents the active standing wave ratio of the feed port of the antenna unit of the present invention. Figure 4 The middle curve represents a curve showing a change in the active standing wave ratio of the feed port of the antenna unit of the present invention with frequency from 0.6 GHz to 1.4 GHz. As can be seen from the figure, the matching bandwidth range of the active standing wave ratio of the antenna unit of the present invention is less than 2 is approximately 0.69 GHz-1.36 GHz. At the center frequency of 1.025 GHz, the calculated impedance matching bandwidth is equal to the percentage ratio of the bandwidth (1.36-0.69) GHz to the center frequency 1.025 GHz, and the impedance matching relative bandwidth with an active standing wave ratio less than 2 is approximately 65.37%.

[0047] Figure 5 This is a simulation result diagram of the maximum achievable gain of the azimuth plane vertical polarization varying with frequency. Figure 5 The horizontal axis represents the frequency, and the vertical axis represents the maximum achievable gain of the vertical polarization in the azimuth plane of the present invention. Figure 5 The middle curve represents the curve of the maximum achievable gain of the azimuth plane vertical polarization of the present invention as the frequency changes from 0.6 GHz to 1.4 GHz. It can be seen from the figure that between 0.69 GHz and 1.36 GHz, the maximum achievable gain of the azimuth plane vertical polarization of the present invention is greater than 4.24 dBi.

[0048] Figure 6 This is a simulation result diagram of the variation of the azimuth plane vertical polarization non-circularity with frequency according to the present invention. Figure 6 The horizontal axis represents the frequency, and the vertical axis represents the azimuth plane vertical polarization non-circularity of the present invention. Figure 6 The middle curve represents the curve of the vertical polarization non-circularity of the azimuth plane of the present invention as the frequency changes from 0.6 GHz to 1.4 GHz. It can be seen from the figure that between 0.69 GHz and 1.36 GHz, the vertical polarization non-circularity of the azimuth plane of the present invention is less than 1.59 dB.

[0049] Example 2

[0050] See also Figure 2, Figure 3(a), Figure 3(b). This embodiment discloses a specific implementation of a broadband omnidirectional antenna unit 1. The broadband omnidirectional antenna unit 1 is composed of a support structure 2, a lower radiating arm 8, a short-circuit block 9, an upper radiating arm 7, a choke 4, a passive coupling structure 5 and a feeding interface 6; the support structure 2 is an annular cylindrical shape, and the lower radiating arm 8 and the upper radiating arm 7 adopt a biconical antenna form with a bowl-shaped structure to widen the working bandwidth of the antenna; the support structure 2 passes through the central circular hole of the choke 4, the lower radiating arm 8, the upper radiating arm 7, and the passive coupling structure 5 and is fixed to the choke 4, the lower radiating arm 8, and the passive coupling structure 5; the lower radiating arm 8 is connected to the upper radiating arm 7 through the short-circuit block 9, and the lower end of the lower radiating arm 8 is connected to the choke 4. An antenna feeding cable channel is provided in the middle of the support structure 2, and the upper end of the lower radiating arm 8 is provided with a feeding interface 6 of the antenna unit to connect with the antenna feeding cable.

[0051] The upper radiating arm 7 is located directly above the lower radiating arm 8 and is at a distance H2 from the lower radiating arm 8 . The upper radiating arm 7 is not connected to the supporting structure 2 , but is connected to the lower radiating arm 8 via the short-circuit block 9 and the feeding interface 6 .

[0052] The choke 4 is located below the lower radiating arm 8, which improves the isolation between antenna units; the passive coupling branch 7 is located above the upper radiating arm 7, which introduces a new resonance point in a coupling manner, thereby improving the working bandwidth of the antenna.

[0053] Example 3

[0054] The broadband omnidirectional antenna unit 1 of this embodiment differs from that of Embodiment 2 in that: further, a short-circuit block 9 is fixed to a side of the lower portion of the upper radiating arm 7 that is offset from the center of the axis, and a feed interface 6 of the antenna unit is provided on a side opposite to the upper end of the lower radiating arm 8, extending from the lower portion to the upper portion of the lower radiating arm 8.

[0055] The position of the feeding interface 6 deviates from the central axis; the position of the short-circuit block 9 deviates from the central axis, and the direction in which the short-circuit block 9 deviates from the center is opposite to the direction in which the feeding interface 6 deviates, thereby improving the symmetry of the radiation pattern.

[0056] Example 4

[0057] The broadband omnidirectional antenna unit 1 of this embodiment is different from that of embodiment 3 in that the short-circuit block 9 deviates from the center of the antenna axis by a distance R1, and the feed interface 6 deviates from the center of the antenna axis in a direction opposite to that of the short-circuit block 9 by a distance R2.

[0058] Preferably, the distance R1 from the center of the short-circuit block 9 is 23 to 33 mm, and the distance R2 from the center of the feed interface 6 is 26 to 36 mm. The lower end of the lower radiating arm 8 has four protruding steps with through holes for mounting the short-circuit block 9. On the opposite side are mounting holes for the feed interface 6 of the antenna unit.

[0059] The short-circuit block 9 is in the shape of a fan-ring cylinder. The feed interface 6 is a two-hole flange SMA type electrical connector.

[0060] Example 5

[0061] The broadband omnidirectional antenna unit 1 of this embodiment differs from the aforementioned embodiments in that: a waist-shaped hole is provided on the side wall of the lower end of the support structure 2, and the direction facing the waist-shaped hole is consistent with the direction in which the feed interface 6 deviates from the center of the antenna axis to achieve connection between the feed cable and the feed interface 6; the lower radiating arm 8, the upper radiating arm 7, the choke 4 and the passive coupling structure 5 are all provided with weight-reducing holes for reducing the weight of the antenna.

[0062] There are four rows of screw holes on the outer surface of the support structure 2, with four screw holes in each row evenly distributed; the hollow in the middle of the support structure 2 provides a channel for the feeding cable to ensure the connection between the antenna feeding cable and the antenna feeding interface 6.

[0063] Two rows of waist-shaped holes evenly distributed in a circular shape are set on the side wall of the lower radiating arm 8. There are 20 waist-shaped holes in each row. The two rows of waist-shaped holes are staggered with each other, achieving the effect of reducing weight without affecting the performance of the antenna; the side wall of the upper radiating arm 7 has the same setting as the side wall of the lower radiating arm 8.

[0064] The upper radiating arm 7 is located directly above the lower radiating arm 8, at a distance H2 from the lower radiating arm 8. The upper radiating arm 7 is not connected to the support structure 2, but is connected to the lower radiating arm 8 via the short-circuit block 9 and the feed interface 6. The upper radiating arm 7 is located directly above the lower radiating arm 8 at a distance H2 of 5 to 8 mm.

[0065] Example 6

[0066] The broadband omnidirectional antenna unit 1 of this embodiment differs from the aforementioned embodiments in that: the choke piece 4 is a circular thin piece, and is connected to the support structure 2 through screw holes provided on the support structure 2; at the same time, the choke piece 4 is connected to the lower radiating arm 8 through a through hole on the step at the lower end of the lower radiating arm 8; the choke piece 4 is located directly below the lower radiating arm 8, and the distance from the lower radiating arm 8 is H1; the choke piece 4 is located directly below the lower radiating arm 8 at H1, and H1 is 3 to 6 mm.

[0067] Two circles of weight-reducing holes are provided on the choke 4. Each circle of weight-reducing holes has 12 holes evenly arranged in a circle, and the two circles of weight-reducing holes are aligned.

[0068] Example 7

[0069] The broadband omnidirectional antenna unit 1 of this embodiment differs from the previous embodiments in that the passive coupling structure 5 is a bowl-shaped structure located directly above the upper radiating arm 7 at a distance H3 from the upper radiating arm 7. The distance H3 between the passive coupling structure 5 and the upper radiating arm 7 is 27 to 35 mm. The passive coupling structure 5 is located directly above the upper radiating arm 7 and is connected to the support structure 2 via screw holes provided in the support structure 2. Its sidewalls have the same configuration as the sidewalls of the lower radiating arm 8.

[0070] Example 8

[0071] See also Figure 1 This embodiment is a broadband omnidirectional high-gain antenna for an in-vehicle communication system. The antenna comprises four identical broadband omnidirectional antenna units 1, forming an array. Adjacent broadband omnidirectional antenna units 1 have a 90° orientation difference around the antenna axis.

[0072] In the broadband omnidirectional high-gain antenna applied to the vehicle communication system, the support structure 2, the lower radiating arm 8, the short-circuit block 9, the upper radiating arm 7, the choke 4 and the passive coupling structure 5 are all made of the same metal material.

[0073] The antenna of the present invention adopts a metal structure as a whole rather than a printed dielectric substrate, which improves the power capacity of the antenna; a biconical antenna is used as an antenna unit to widen the antenna bandwidth, and a passive coupling structure 5 is used to introduce a new resonance point for the antenna to further expand the antenna bandwidth; the radiation pattern is adjusted by arranging a short-circuit block 9 at a specific position, and the antenna array method is improved to enable the antenna to have a wider pattern bandwidth.

[0074] Simulation results show that the -10dB relative bandwidth of the present invention is 65.37%. In the entire frequency band, the maximum horizontal gain is greater than 4.24dBi, the maximum value is 8.27dBi, and the out-of-roundness is less than 1.59dB. The present invention has the advantages of simple feeding, higher gain, and wider bandwidth.

[0075] The foregoing description is merely a preferred embodiment of the present invention and does not constitute a limitation of the present invention. Those skilled in the art, guided by the prior art, may make other modifications to the implementation of the present invention without inventive effort. Any modifications made within the spirit and principles of the present invention, or simple replacements or equivalent substitutions using conventional techniques in the art, shall be included within the scope of protection of the present invention.

Claims

1. A broadband omnidirectional antenna unit (1), comprising a support structure (2), a radiation structure (3), a choke (4), a passive coupling structure (5) and a feed interface (6), characterized in that: The support structure (2) passes through the central circular hole of the radiation structure (3), the choke (4), and the passive coupling structure (5), and a channel for the antenna feeding coaxial line is provided in the middle; the radiation structure (3) is composed of an upper radiation arm (7), a lower radiation arm (8), and a short-circuit block (9); the upper radiation arm (7) and the lower radiation arm (8) adopt the form of a biconical antenna to widen the antenna standing wave bandwidth; the short-circuit block (9) adopts a fan-ring cylindrical structure and is arranged at a position deviated from the central axis; the passive coupling structure (5) adopts a bowl-shaped structure and is arranged directly above the radiation structure (3); the feeding interface (6) is arranged on the lower radiation arm (8), and the feeding interface (6) deviates from the central axis and is opposite to the deviation direction of the short-circuit block (9).

2. The broadband omnidirectional antenna unit (1) according to claim 1, characterized in that: The short-circuit block (9) is arranged between the upper radiating arm (7) and the lower radiating arm (8) and at a position offset from the central axis. The feed interface (6) is arranged on a side of the lower radiating arm (8) close to the upper radiating arm (7). The feed interface (6) extends from the bottom to the top of the lower radiating arm (8).

3. The broadband omnidirectional antenna unit (1) according to claim 2, characterized in that: The short-circuit block (9) deviates from the center of the antenna axis by a distance R1, and the feed interface (6) deviates from the center of the antenna axis in a direction opposite to that of the short-circuit block (9), and the deviation distance is R2.

4. The broadband omnidirectional antenna unit (1) according to claim 3, characterized in that: The distance R1 of the short-circuit block (9) from the center is 23 to 33 mm; the distance R2 of the feed interface (6) from the center of the antenna axis is 26 to 36 mm.

5. The broadband omnidirectional antenna unit (1) according to any one of claims 1 to 4, characterized in that: A waist-shaped hole is provided on the side wall of the lower end of the support structure (2), and the direction in which the waist-shaped hole faces is consistent with the direction in which the feed interface (6) deviates from the center of the antenna axis, so as to realize the connection between the feed coaxial line and the feed interface (6); and weight-reducing holes are provided on the lower radiating arm (8), the upper radiating arm (7), the choke (4) and the passive coupling structure (5) to reduce the weight of the antenna.

6. The broadband omnidirectional antenna unit (1) according to any one of claims 1 to 4, characterized in that: The upper radiation arm (7) is located directly above the lower radiation arm (8), and the distance between the upper radiation arm (7) and the lower radiation arm (8) is H2.

7. The broadband omnidirectional antenna unit (1) according to claim 6, characterized in that: The choke piece (4) is a circular thin piece, and the choke piece (4) is connected to the support structure (2) through a screw hole provided on the support structure (2); at the same time, the choke piece (4) is connected to the lower radiating arm (8) through a through hole on a step at the lower end of the lower radiating arm (8); the choke piece (4) is located at H1 directly below the lower radiating arm (8), and H1 is 3 to 6 mm.

8. The broadband omnidirectional antenna unit (1) according to claim 6, characterized in that: The passive coupling structure (5) is a bowl-shaped structure. The passive coupling structure (5) is located at a position H3 directly above the upper radiation arm (7). The distance H3 between the passive coupling structure (5) and the upper radiation arm (7) is 27 to 35 mm.

9. A broadband omnidirectional high-gain antenna for use in an on-vehicle communication system based on the broadband omnidirectional antenna unit according to any one of claims 1 to 8, comprising four identical broadband omnidirectional antenna units (1), wherein the four broadband omnidirectional antenna units (1) are arrayed, and two adjacent broadband omnidirectional antenna units (1) have a 90° orientation angle difference around the antenna axis.

10. The broadband omnidirectional high-gain antenna for an in-vehicle communication system according to claim 9, characterized in that: The supporting structure (2), the lower radiation arm (8), the short-circuit block (9), the upper radiation arm (7), the choke piece (4) and the passive coupling structure (5) are all made of the same metal material.

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