阅读说明：本技术 一种全向、垂直极化、电小滤波天线 (Omnidirectional, vertical polarization and electric small filtering antenna ) 是由 唐明春 郭飘 李大疆 胡坤志 李梅 理查德·齐奥尔科夫斯基 于 2021-09-13 设计创作，主要内容包括：本发明公开了一种全向、垂直极化、电小滤波天线,包括与下层介质基板平行的上层介质基板；顶帽加载的单极子包括圆形贴片设置在上层介质基板上表面,驱动柱连接圆形贴片与馈线部分；短路柱垂直设置在上层介质基板与下层介质基板之间,并连接圆形贴片和金属地板；馈线部分设置于下层介质基板的上表面；同轴电缆的内导体连接馈线部分和驱动柱,同轴电缆的外导体连接金属地板,金属地板设置在下层介质基板的下表面。本天线采用圆形顶帽加载的单极子结构由此降低单极子的剖面高度和减小尺寸,采用混合的滤波结构来实现优异的滤波性能,而且可以拓宽天线的工作带宽,实现了在保持一个电小尺寸的同时还具有良好频率选择和带外抑制特性。(The invention discloses an omnidirectional, vertical polarization and small electric filtering antenna, which comprises an upper dielectric substrate parallel to a lower dielectric substrate; the monopole loaded on the top cap comprises a circular patch arranged on the upper surface of the upper-layer medium substrate, and the driving column is connected with the circular patch and the feeder line part; the short circuit column is vertically arranged between the upper-layer dielectric substrate and the lower-layer dielectric substrate and is connected with the circular patch and the metal floor; the feeder line part is arranged on the upper surface of the lower-layer dielectric substrate; the inner conductor of the coaxial cable is connected with the feeder line part and the driving column, the outer conductor of the coaxial cable is connected with the metal floor, and the metal floor is arranged on the lower surface of the lower-layer dielectric substrate. The antenna adopts the monopole structure loaded by the circular top cap, so that the profile height and the size of the monopole are reduced, the excellent filtering performance is realized by adopting the mixed filtering structure, the working bandwidth of the antenna can be widened, and the antenna has good frequency selection and out-of-band rejection characteristics while keeping the small size.)

1. An omnidirectional, vertically polarized and electrically small filtering antenna is characterized by comprising an upper dielectric substrate (1), a lower dielectric substrate (2), a top cap loaded monopole (3), a short-circuit column (4), a feeder line part (5), a coaxial cable (6) and a metal floor (7);

the upper-layer dielectric substrate (1) is parallel to the lower-layer dielectric substrate (2), and the upper-layer dielectric substrate (1) is positioned above the lower-layer dielectric substrate (2);

the top cap loaded monopole (3) comprises a circular patch (8) and a driving column (9);

the circular patch (8) is arranged on the upper surface of the upper-layer dielectric substrate (1), the driving column (9) is vertically arranged between the upper-layer dielectric substrate (1) and the lower-layer dielectric substrate (2), and the driving column (9) is connected with the circular patch (8) and the feeder line part (5);

the short-circuit column (4) is vertically arranged between the upper-layer dielectric substrate (1) and the lower-layer dielectric substrate (2), and the short-circuit column (4) is connected with the circular patch (8) and the metal floor (7);

the feeder line part (5) is arranged on the upper surface of the lower-layer dielectric substrate (2);

the inner conductor of the coaxial cable (6) is connected with the feeder line part (5) and the driving column (9), the outer conductor of the coaxial cable (6) is connected with the metal floor (7), and the metal floor (7) is arranged on the lower surface of the lower-layer dielectric substrate (2).

2. An omnidirectional, vertically polarized, electrically small filter antenna according to claim 1, wherein the material of the upper dielectric substrate (1) and the lower dielectric substrate (2) is Rogers RO4003, the dielectric constants of the upper dielectric substrate (1) and the lower dielectric substrate (2) are 3.55, the loss tangents of the upper dielectric substrate (1) and the lower dielectric substrate (2) are 0.0027, and the thicknesses of the upper dielectric substrate (1) and the lower dielectric substrate (2) are H₁And H₂Said H is₁＝H₂The radius of the upper dielectric substrate (1) is 15mm, and the radius of the lower dielectric substrate (2) is 21 mm;

the axis of the upper-layer dielectric substrate (1) coincides with the axis of the lower-layer dielectric substrate (2).

3. An omnidirectional, vertically polarized, electrically small filtering antenna according to claim 2, characterized in that the axis of the circular patch (8) coincides with the axis of the upper dielectric substrate (1);

half of the circular patch (8)Diameter R₁15mm, the diameter D of the drive column (9)₁The distance between the axis of the driving column (9) and the axis of the circular patch (8) is 3mm, 4 mm.

4. An omnidirectional, vertically polarized, electrically small filtering antenna according to claim 2, characterized in that said shorting pillar (4) has a diameter D₂The short circuit column (4) is located on one side, away from the axis of the upper-layer dielectric substrate (1), of the driving column (9), and the axis of the short circuit column (4), the axis of the upper-layer dielectric substrate (1) and the axis of the driving column (9) are located on the same vertical plane;

the distance between the axis of the short-circuit column (4) and the axis of the upper-layer dielectric substrate (1) is 9 mm.

5. An omnidirectional, vertically polarized, electrically small filter antenna according to claim 1, wherein the radius of the inner conductor of the coaxial cable (6) is 0.45mm, the length of the coaxial cable (6) is 6mm, the inner diameter of the outer conductor of the coaxial cable (6) is 1.5mm, and the outer diameter of the outer conductor of the coaxial cable (6) is 1.7 mm.

6. An omnidirectional, vertically polarized, electrically small filtering antenna according to claim 1, characterized in that the radius of said metal floor (7) is 165mm, the thickness of said metal floor (7) is 1mm, the distance between said metal floor (7) and the upper dielectric substrate (1) is H, said H being 11.3 mm.

7. An omnidirectional, vertically polarized, electrically small filtering antenna according to claim 1, wherein said feed portion (5) comprises a first stub module and a second stub module, said first stub module and said second stub module being disposed on the upper surface of the lower dielectric substrate (2);

the first branch module comprises an arc branch I (22), a first rectangular branch I (23) and a second rectangular branch I (24);

the arc-shaped branch section I (22) is connected to one end of a first rectangular branch section I (23), the first rectangular branch section I (23) is connected with an inner conductor of the coaxial cable (6), and a second rectangular branch section I (24) is arranged on one side, far away from a feed point, of the first rectangular branch section I (23) in parallel;

the width W of the first rectangular support section I (23)_S11.5mm, the length L of the first rectangular strut I (23)_S111mm, the distance S between one end of the first rectangular branch section I (23) far away from the arc branch section I (22) and the feed point₄4.5mm, the width W of the arc-shaped branch section I (22)₃2mm, the arc primary point of arc branch node I (22) coincides with the feed point, the arc bending angle theta of arc branch node I (22)₁32 °, length L of second rectangular leg i (24)₁2mm, the width W of the second rectangular strut I (24)₁2.5mm, the distance S between the bottom edge of the second rectangular branch section I (24) far away from the arc branch section I (22) and the feed point₅＝2mm；

The second branch joint module comprises a rectangular branch joint II (25), an arc branch joint II (26) and a rectangular groove (27);

the rectangular branch section II (25) is parallel to the first rectangular branch section I (23), the rectangular branch section II (25) is also connected with an inner conductor of the coaxial cable (6), an arc branch section II (26) is arranged at one end of the rectangular branch section II (25), and the arc branch section II (26) is positioned on one side, far away from the arc branch section I (22), of the rectangular branch section II (25);

the clearance air gap g between the first rectangular branch section I (23) and the rectangular branch section II (25) is 0.2mm, and the length L of the rectangular branch section II (25)_S215.5mm, width W of the rectangular strut II (25)_S21.5mm, arc-shaped tributary section II (26) is kept away from arc-shaped tributary section II (26) one end and distance S of feed point₃12mm, the width W of the arch-shaped strut II (26)₄2.5mm, the arc origin of the arc branch node II (26) coincides with the feed point, and the arc bending angle theta of the arc branch node II (26)₂＝30°；

The rectangular groove (27) is arranged between a feeding point on the rectangular branch node II (25) and the arc branch node II (26), the rectangular groove (27) is positioned on one side of the arc branch node II (26) close to the feeding point, and the length L of the rectangular groove (27) is₂11mm, saidThe width W of the rectangular groove (27)₂0.5mm, the minimum perpendicular distance S between the rectangular slot (27) and the feeding point₈＝2mm。

Technical Field

The invention belongs to the technical field of antennas, and relates to an omnidirectional, vertical polarization and small electric filtering antenna.

Background

Vertically polarized antennas have the performance advantage over horizontally polarized antennas that their path loss is inherently much smaller when the electromagnetic waves propagate in a lossy medium, such as the earth or the ground. Therefore, the vertically polarized antenna has been widely applied to many practical engineering scenarios other than land, water and air vehicles, such as unattended ground sensor networks, wireless local area network systems, communication and sensing in tunnel environments, and road radio frequency identification smart parking systems, and so on.

In recent years, a filtering antenna, i.e., an antenna and a filter integrated into one module, has been attracting attention because of its small size advantage. In particular, vertically polarized filtering antennas have an additional desirable advantage over simple vertically polarized antennas in that they can provide both radiation and filtering functions. However, only one vertical polarization filtering antenna is reported at present. The filter response is realized by loading an annular groove and four short-circuit columns in a dielectric resonator and feeding by adopting a mixed structure. Due to its operating characteristics, a dielectric resonator has an inevitably high profile, thereby resulting in its electrically large size, which is not suitable for wireless platforms where space is limited.

Disclosure of Invention

The invention aims to provide an omnidirectional, vertically polarized and electrically small filtering antenna which has the performances of small size, simple structure, high frequency selection and out-of-band rejection.

The invention is realized by the technical scheme, which comprises an upper dielectric substrate, a lower dielectric substrate, a top cap loaded monopole, a short-circuit column, a feeder part, a coaxial cable and a metal floor;

the upper dielectric substrate is parallel to the lower dielectric substrate, and the upper dielectric substrate is positioned above the lower dielectric substrate;

the top cap loaded monopole comprises a circular patch and a driving column;

the circular patch is arranged on the upper surface of the upper-layer dielectric substrate, the driving column is vertically arranged between the upper-layer dielectric substrate and the lower-layer dielectric substrate, and the driving column is connected with the circular patch and the feeder line part;

the short-circuit column is vertically arranged between the upper-layer dielectric substrate and the lower-layer dielectric substrate and is connected with the circular patch and the metal floor;

the feeder line part is arranged on the upper surface of the lower-layer dielectric substrate;

the inner conductor of the coaxial cable is connected with the feeder line part and the driving column, the outer conductor of the coaxial cable is connected with the metal floor, and the metal floor is arranged on the lower surface of the lower-layer dielectric substrate.

Preferably, the material of the upper dielectric substrate and the material of the lower dielectric substrate are both Rogers RO4003, the dielectric constants of the upper dielectric substrate and the lower dielectric substrate are both 3.55, the loss tangents of the upper dielectric substrate and the lower dielectric substrate are both 0.0027, and the thicknesses of the upper dielectric substrate and the lower dielectric substrate are respectively H₁And H₂Said H is₁＝H₂The radius of the upper dielectric substrate is 15mm, and the radius of the lower dielectric substrate is 21 mm;

the axis of the upper-layer dielectric substrate coincides with the axis of the lower-layer dielectric substrate.

Preferably, the axis of the circular patch coincides with the axis of the upper-layer dielectric substrate;

radius R of the circular patch₁15mm, diameter D of the drive column₁The distance between the axis of the drive column and the axis of the circular patch is 3mm, 4 mm.

Preferably, the short-circuiting pillars have a diameter D₂The short-circuit column is positioned on one side, away from the axis of the upper-layer dielectric substrate, of the driving column, and the axis of the short-circuit column, the axis of the upper-layer dielectric substrate and the axis of the driving column are positioned on the same vertical plane;

the distance between the axis of the short-circuit column and the axis of the upper-layer dielectric substrate is 9 mm.

Preferably, the radius of the inner conductor of the coaxial cable is 0.45mm, the length of the coaxial cable is 6mm, the inner diameter of the outer conductor of the coaxial cable is 1.5mm, and the outer diameter of the outer conductor of the coaxial cable is 1.7 mm.

Preferably, the radius of the metal floor is 165mm, the thickness of the metal floor is 1mm, the distance between the metal floor and the upper dielectric substrate is H, and H is 11.3 mm.

Preferably, the feeder part comprises a first branch module and a second branch module, and the first branch module and the second branch module are both arranged on the upper surface of the lower-layer dielectric substrate;

the first branch module comprises an arc branch I, a first rectangular branch I and a second rectangular branch I;

the arc-shaped branch section I is connected to one end of a first rectangular branch section I, the first rectangular branch section I is connected with an inner conductor of the coaxial cable, and a second rectangular branch section I is arranged on one side, far away from a feed point, of the first rectangular branch section I in parallel;

the width W of the first rectangular support section I_S11.5mm, the length L of the first rectangular strut I_S111mm, first rectangle minor axis I keeps away from arc minor axis I' S one end and distance S of feed point₄4.5mm, the width W of the arc-shaped branch section I₃2mm, the arc primary point of arc branch node I coincides with the feed point, the arc bending angle theta of arc branch node I₁32 °, length L of the second rectangular leg i₁2mm, the width W of the second rectangular support section I₁2.5mm, the distance between the bottom edge of the second rectangular branch section I far away from the arc branch section I and the feed pointS₅＝2mm；

The second branch joint module comprises a rectangular branch joint II, an arc branch joint II and a rectangular groove;

the rectangular branch section II is parallel to the first rectangular branch section I, the rectangular branch section II is also connected with an inner conductor of the coaxial cable, an arc branch section II is arranged at one end of the rectangular branch section II, and the arc branch section II is positioned on one side, far away from the arc branch section I, of the rectangular branch section II;

the clearance air gap g between the first rectangular branch section I and the rectangular branch section II is 0.2mm, and the length L of the rectangular branch section II is equal to that of the rectangular branch section II_S215.5mm, the width W of the rectangular strut II_S21.5mm, arc branch festival II keeps away from arc branch festival II one end and the distance S of feed point₃12mm, the width W of the arc-shaped branch section II₄2.5mm, the arc origin of the arc branch node II coincides with the feed point, and the arc bending angle theta of the arc branch node II₂＝30°；

The rectangular channel is arranged between a feed point and the arc branch node II on the rectangular branch node II, the rectangular channel is positioned on one side of the arc branch node II close to the feed point, and the length L of the rectangular channel₂Width W of the rectangular groove being 11mm₂0.5mm, the minimum perpendicular distance S between the rectangular slot and the feed point₈＝2mm。

After adopting the structure, compared with the prior art, the invention has the following advantages:

1. two zero points are generated by adopting the novel mixed filtering structure, so that a band-pass filtering effect is realized;

2. by adopting the novel hybrid filtering structure, an additional resonance point is introduced, so that the bandwidth is expanded;

3. due to the adoption of the novel hybrid filtering structure, the filter can be completely arranged below the patch, so that the electrically small size is realized;

4. due to the adoption of the novel hybrid filtering structure, the omnidirectional vertical polarization can be realized under the condition of keeping excellent filtering performance.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof.

Drawings

The drawings of the present invention are described below.

FIG. 1 is a three-dimensional view of the overall structure of an omnidirectional, vertically polarized, electrically small filtering antenna of the present invention;

FIG. 2 is a side view of the overall structure of the omnidirectional, vertically polarized, electrically small filtering antenna of the present invention;

FIG. 3 is a front view of the overall structure of the feed line in the omnidirectional, vertically polarized, electrically small filtering antenna of the present invention;

FIG. 4 shows the simulated impedance bandwidth (S) of the omnidirectional, vertically polarized, electrically small filter antenna of the present invention₁₁Less than or equal to-10 dB) and can realize gain;

FIG. 5 is a graph of the overall efficiency of the omnidirectional, vertically polarized, electrically small filtering antenna of the present invention;

FIG. 6 is a simulated two-dimensional radiation pattern of the omnidirectional, vertically polarized, electrically small filter antenna in the ZOY plane and the XOY plane at the frequency point of 1.85GHz in accordance with the present invention;

FIG. 7 is a three-dimensional view of the overall structure of the directional, vertically polarized, electrically small filtering antenna of the present invention;

FIG. 8 is a side view of the overall structure of a directional, vertically polarized, electrically small filtered antenna of the present invention;

FIG. 9 is a front view of the overall structure of the top hat in the directional, vertically polarized, electrically small filtering antenna of the present invention;

FIG. 10 is a front view of the overall structure of the feed line in the directional, vertically polarized, electrically small filter antenna of the present invention;

FIG. 11 is a graph of simulated impedance bandwidth (S) of a directional, vertically polarized, electrically small filter antenna of the present invention₁₁Less than or equal to-10 dB) and can realize gain;

FIG. 12 is a graph of the overall efficiency of the directional, vertically polarized, electrically small filter antenna of the present invention;

fig. 13 is a simulated two-dimensional radiation pattern of the directional, vertically polarized, electrically small filter antenna in the ZOY plane and XOY plane at the frequency of 2.05GHz in accordance with the present invention.

In the figure: 1. an upper dielectric substrate; 2. a lower dielectric substrate; 3. a top-cap loaded monopole; 4. a shorting post; 5. a feeder section; 6. a coaxial cable; 7. a metal floor; 8. circular patch; 9. a drive column; 10. the upper dielectric substrate of the directional filter; 11. a directional filtering lower dielectric substrate; 12. a monopole loaded on the first directional filtering top cap; 13. a second directionally filtered top hat loaded monopole; 14. a directional filtering short-circuit column; 15. a directional filter feeder section; 16. a directional filtering coaxial cable; 17. a directional filtering metal floor; 18. a first directional filtering sector patch; 19. a first directional filtering drive column; 20. a second directional filtering sector patch; 21. a second directional filtering drive column; 22. an arc-shaped branch section I; 23. a first rectangular branch section I; 24. a second rectangular branch section I; 25. a rectangular branch section II; 26. an arc-shaped branch section II; 27. a rectangular groove.

Detailed Description

The invention is further illustrated by the following figures and examples.

As shown in fig. 1 to 6, an omnidirectional, vertically polarized, electrically small filtering antenna includes an upper dielectric substrate 1, a lower dielectric substrate 2, a top-hat loaded monopole 3, a shorting post 4, a feeder portion 5, a coaxial cable 6, and a metal floor 7;

the upper dielectric substrate 1 is parallel to the lower dielectric substrate 2, and the upper dielectric substrate 1 is positioned above the lower dielectric substrate 2;

the top cap loaded monopole 3 comprises a circular patch 8 and a driving column 9;

the circular patch 8 is arranged on the upper surface of the upper-layer dielectric substrate 1, the driving column 9 is vertically arranged between the upper-layer dielectric substrate 1 and the lower-layer dielectric substrate 2, and the driving column 9 is connected with the circular patch 8 and the feeder line part 5;

the short-circuit column 4 is vertically arranged between the upper-layer dielectric substrate 1 and the lower-layer dielectric substrate 2, and the short-circuit column 4 is connected with the circular patch 8 and the metal floor 7;

the feeder line part 5 is arranged on the upper surface of the lower-layer dielectric substrate 2;

the inner conductor of the coaxial cable 6 is connected with the feeder line part 5 and the driving column 9, the outer conductor of the coaxial cable 6 is connected with the metal floor 7, and the metal floor 7 is arranged on the lower surface of the lower-layer dielectric substrate 2.

The dielectric substrate comprises an upper dielectric substrate 1 and a lower dielectric substrate 2, wherein the upper dielectric substrate 1 and the lower dielectric substrate 2 are made of Rogers RO4003, the dielectric constants of the upper dielectric substrate 1 and the lower dielectric substrate 2 are both 3.55, the loss tangents of the upper dielectric substrate 1 and the lower dielectric substrate 2 are both 0.0027, and the thicknesses of the upper dielectric substrate 1 and the lower dielectric substrate 2 are respectively H₁And H₂Said H is₁＝H₂The radius of the upper dielectric substrate 1 is 15mm, and the radius of the lower dielectric substrate 2 is 21 mm;

the axis of the upper layer medium substrate 1 coincides with the axis of the lower layer medium substrate 2.

The axis of the circular patch 8 is coincided with the axis of the upper-layer dielectric substrate 1;

radius R of the circular patch 8₁15mm, the diameter D of the drive column 9₁The distance between the axis of the drive column 9 and the axis of the circular patch 8 is 3mm, 4 mm.

Diameter D of the shorting post 4₂The short-circuit column 4 is positioned on one side, away from the axis of the upper-layer dielectric substrate 1, of the driving column 9, and the axis of the short-circuit column 4, the axis of the upper-layer dielectric substrate 1 and the axis of the driving column 9 are positioned on the same vertical plane;

the distance between the axis of the short-circuit column 4 and the axis of the upper-layer dielectric substrate 1 is 9 mm.

The radius of the inner conductor of the coaxial cable 6 is 0.45mm, the length of the coaxial cable 6 is 6mm, the inner diameter of the outer conductor of the coaxial cable 6 is 1.5mm, and the outer diameter of the outer conductor of the coaxial cable 6 is 1.7 mm.

The radius of the metal floor 7 is 165mm, the thickness of the metal floor 7 is 1mm, the distance between the metal floor 7 and the upper-layer dielectric substrate 1 is H, and H is 11.3 mm.

The feeder line part 5 comprises a first branch module and a second branch module, and the first branch module and the second branch module are both arranged on the upper surface of the lower-layer dielectric substrate (2);

the first branch module comprises an arc branch I22, a first rectangular branch I23 and a second rectangular branch I24;

the arc-shaped branch section I22 is connected to one end of a first rectangular branch section I23, the first rectangular branch section I23 is connected with an inner conductor of the coaxial cable 6, and a second rectangular branch section I24 is arranged on one side, far away from a feeding point, of the first rectangular branch section I23 in parallel;

the width W of the first rectangular support section I23_S11.5mm, the length L of the first rectangular stub I23_S111mm, the distance S between one end of the first rectangular branch section I23 far away from the arc branch section I22 and the feed point₄4.5mm, the width W of the arc-shaped branch section I22₃2mm, the arc primary point of arc branch node I22 coincides with the feed point, the arc bending angle theta of arc branch node I22₁32 °, length L of second rectangular leg i 24₁2mm, the width W of the second rectangular support section I24₁2.5mm, the distance S between the bottom edge of the second rectangular branch section I24 far away from the arc branch section I22 and the feed point₅＝2mm；

The second branch node module comprises a rectangular branch node II25, an arc branch node II26 and a rectangular groove 27;

the rectangular branch section II25 is parallel to the first rectangular branch section I23, the rectangular branch section II25 is also connected with the inner conductor of the coaxial cable 6, one end of the rectangular branch section II25 is provided with an arc branch section II26, and the arc branch section II26 is positioned on one side of the rectangular branch section II25 away from the arc branch section I22;

the clearance air gap g between the first rectangular branch section I23 and the rectangular branch section II25 is 0.2mm, and the length L of the rectangular branch section II25_S215.5mm, width W of the rectangular strut II25_S21.5mm, the distance S between one end of the arc branch II26 far away from the arc branch II26 and the feed point₃12mm, width W of the arch-shaped branch II26₄2.5mm, the arc origin of the arc branch node II26 is connected with the feed pointCoincidence, the arc bending angle theta of the arc branch section II26₂＝30°；

The rectangular groove 27 is arranged between a feeding point on the rectangular branch node II25 and the arc branch node II26, the rectangular groove 27 is arranged on one side of the arc branch node II26 close to the feeding point, and the length L of the rectangular groove 27₂Width W of the rectangular groove 27 being 11mm₂0.5mm, the minimum perpendicular distance S of the rectangular slot 27 from the feed point₈＝2mm。

The first branch module and the second branch module are quarter open-circuit branches, wherein the first branch module generates a high-frequency zero point, and excellent filtering performance is realized on an upper stop band; the second branch node module forms a low-frequency zero point, so that excellent filtering performance is realized at a lower stop band, namely the compact and simple feeder line can realize high-frequency selection characteristics, and band-pass filtering response is brought; the first branch node module and the second branch node module form a half-wavelength resonator by feeding a common coaxial line, a resonance peak is generated in a pass band, and the loading of the short-circuit column 4 can promote the resonance peaks of the two modes to be overlapped so as to realize the expansion of the bandwidth; because the first rectangular branch section I23 of the first branch section module and the rectangular branch section II25 of the second branch section module are arranged in parallel, the top arc-shaped branch section I22 and the arc-shaped branch section II26 are bent in opposite directions, and the energy of the top arc-shaped branch section I22 and the top arc-shaped branch section II26 in the side radiation direction are mutually cancelled, the antenna can keep vertical polarization radiation in the whole passband.

Table 1 table of various parameter sizes of omni-directional filtering antenna in the present invention

According to the parameters in table 1, high frequency electromagnetic simulation software HFSS is used to perform simulation analysis on the S parameters, two-dimensional radiation pattern, radiation gain and other characteristic parameters of the designed omnidirectional, vertical polarization and electrically small filtering antenna with high performance, and based on the characteristics parameters, a final object is obtained and tested, the simulation and test results are shown in fig. 4-6, and the results are specifically analyzed as follows:

as shown in FIG. 4, the S parameter and radiation gain in the simulation and test case of the filtering antenna of the present invention are shown, in this case, | S₁₁|<-an impedance bandwidth range of 1.74-1.96GHz (11.9%) with a physical test value of 1.76-1.97GHz (11.3%) under 10 dB; the simulated peak gain was 3.65dBi, while the measured peak gain was 3.01 dBi. It can be found that both simulation and test have two radiation zeros and have excellent frequency selection characteristics.

As shown in fig. 5, the total efficiency in the simulated pass band is greater than 85%, and the total efficiency in the pass band of the physical test is greater than 83%.

As shown in fig. 6, the radiation patterns of the omni-directional filtering antenna in the ZOY plane and the XOY plane at 1.85GHz in the present invention are respectively shown, and it can be seen from the figure that the XOY plane of the antenna exhibits omni-directional radiation and has good cross polarization.

In summary, the omni-directional filtering antenna has good impedance matching characteristics, filtering characteristics and a good and stable omni-directional radiation pattern.

As shown in fig. 7 to 10, a directional, vertically polarized, electrically small filtering antenna includes a directional filtering upper dielectric substrate 10, a directional filtering lower dielectric substrate 11, a monopole 12 loaded on a first directional filtering top cap, a monopole 13 loaded on a second directional filtering top cap, a directional filtering short circuit column 14, a directional filtering feeder line part 15, a directional filtering coaxial cable 16, and a directional filtering metal floor 17;

the upper surface of the directional filtering upper-layer dielectric substrate 10 is provided with a first directional filtering fan-shaped patch 18 and a second directional filtering fan-shaped patch 20, the monopole 12 loaded on the first directional filtering top cap is connected with the first directional filtering fan-shaped patch 18, the monopole 13 loaded on the second directional filtering top cap is connected with the second directional filtering fan-shaped patch 20, the arc-shaped circle center of the first directional filtering fan-shaped patch 18 and the arc-shaped circle center of the second directional filtering fan-shaped patch 20 are coincided with the circle center of the directional filtering upper-layer dielectric substrate 10, and the first directional filtering fan-shaped patch 20The opening angles of the fan-shaped patch 18 and the second directional filtering fan-shaped patch 20 are theta₁120 degrees, the width of the zigzag groove is W1 mm, and the radius of the circular arc is R₄4mm, the length of the fold line is L₁3.5mm, the center of the left meander line is apart from the center S of the antenna₄13.75mm, the center of the right meander line is apart from the center S of the antenna₅A directional filter driving column 19 is vertically arranged and connected with the first directional filter sector patch 18 and the directional filter feeder line part 15, and the diameter of the directional filter driving column is D₂3.2mm, its center is distant from the antenna center S₂The directional filtering short circuit column 21 is vertically arranged and connected with the second directional filtering fan-shaped patch 20 and the directional filtering metal floor 17, and the diameter of the directional filtering short circuit column is D₃4.4mm, its center is distant from the antenna center S₃＝14.8mm。

The loading of the fan-shaped top cap greatly reduces the section height of the monopole, thereby reducing the size; the fan-shaped top caps are etched with the zigzag wire grooves, the zigzag wire grooves increase the path of surface current, and the working frequency of the antenna is reduced, so that the small size is realized; two monopoles are placed side by side, the left monopole acts as a director, and the right monopole acts as a reflector, thereby forming a quasi-Yagi antenna structure, producing end-fire radiation.

The materials of the directional filter upper dielectric substrate 10 and the directional filter lower dielectric substrate 11 are Rogers RO4003, the dielectric constant of the materials is 3.55, the loss tangent of the materials is 0.0027, and the radius R of the directional filter upper dielectric substrate 10 and the radius R of the directional filter lower dielectric substrate 11 are respectively equal to that of the dielectric substrate₁The thickness of the substrate is 0.813mm, and the air gap H between the upper dielectric substrate 10 and the lower dielectric substrate 11 is 8.37 mm.

The directional filtering short circuit column 14 is connected with a first directional filtering fan-shaped patch 18 and a directional filtering metal floor 17, and the diameter of the directional filtering short circuit column is D₁2.6mm with its center 13.2mm from the center of the antenna.

The directional filter feeder line part 15 is positioned on the upper surface of the directional filter lower-layer dielectric substrate 11;

the radius of the inner conductor of the directional filtering coaxial cable 16 is 0.45-0.55mm, the length of the cable is 6-7mm, the inner diameter of the outer conductor is 1.5-1.6mm, and the outer diameter of the outer conductor is 1.7-1.8 mm.

The directional filtering metal floor 17 is positioned on the lower surface of the directional filtering lower-layer dielectric substrate 11 and is a cylinder with the radius of 150mm and the thickness of 1 mm.

The directional filter feeder section 15 includes a stub I, a feed point spaced from its bottom end S₆0.8mm, length L_s117.2mm, width W_s13.4mm, and a branch section II of an etched rectangular groove, wherein the feed point is far away from the bottom end S of the rectangular groove₇3.8mm, length L_s217.7mm, width W_s22.3mm, the tip bending width is W₅1.9mm and a bending angle theta₂41 DEG, the length of the rectangular groove is L₄10.7mm, width W₄1mm, and the air gap between the branch joint I and the branch joint II is g 0.2 mm.

The feeder part 16 adopts the design of an omnidirectional filtering antenna, namely two quarter open-circuit stubs with different lengths and a short-circuit column; the introduction of the branch nodes I and II respectively generates a zero point at the edges of high and low frequency pass bands, so the filtering performance can be maintained, similarly, the half-wavelength resonance formed by the same coaxial feed of the two branch nodes generates a resonance peak in the pass band, and the loading of the short-circuit column promotes the superposition of a monopole sub-mode and a branch node mode, thereby playing the role of expanding the bandwidth of the antenna and further verifying the function of the hybrid filtering structure provided in the omnidirectional filtering antenna; since the feed line portion 16 is still located directly below the radiating patch, the directional filter antenna can achieve a filter response while maintaining an electrically small size.

Table 2 table of the size of each parameter of the directional filtering antenna of the present invention

According to the parameters in table 2, HFSS is used to perform simulation analysis on the S parameters, two-dimensional radiation pattern, radiation gain, and other characteristic parameters of the designed directional, vertical polarization, electrically small filtering antenna with high performance, and based on the simulation analysis, a final object is obtained and tested, the simulation and test results are shown in fig. 11-13, the results are basically matched, and the specific analysis on the results is as follows:

as shown in fig. 11 and 12, S parameter, radiation gain and total efficiency under the simulation and test condition of the directional filtering antenna in the present invention, | S in the simulation₁₁|<Under the condition of-10 dB, the impedance bandwidth range is 1.91-2.19GHz (13.7%), the corresponding passband simulation peak gain is 6.34dBi, and the total efficiency in the passband is more than 80%; under test, | S₁₁|<Under the condition of-10 dB, the impedance bandwidth range is 1.9-2.16GHz (12.8%), the corresponding passband simulation gain range is 6.09dBi, and the total efficiency in the passband is more than 78%; both the simulated and the tested gain curves have two zeros.

As shown in fig. 13, it can be seen that the radiation patterns of the circular polarization filter antenna in the ZOY plane and the XOY plane respectively at 2.05GHz in the present invention are end-fire radiation, and the cross polarization is good.

In summary, the directional filter antenna has good impedance matching characteristics, good filtering characteristics, and a good and stable end-fire radiation pattern.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.