A backfire antenna with broadband and beam equalization characteristics

Abstract

The application discloses a backfire antenna with broadband and beam equalization characteristics, and belongs to the fields of antennas, microwave technology and Internet of Things. The antenna is composed of an elliptical main reflector, a sector dipole and an elliptical sub-reflector. A pair of rectangular slots are opened on the surface of the sector dipole, and a pair of tuning branches are added to disturb the excited modes together, so that the broadband characteristics are realized. The reflector is used to realize good beam equalization characteristics. The performances of the antenna are controlled by the major and minor axis radii of the reflector, the length and width of the rectangular slots, the size of the branches, the central angle of the sector dipole and the size of the radius of the sector dipole. The application has the characteristics of small volume, simple structure and low manufacturing cost, and has wide application prospects in various wireless sensing and various radio frequency identification systems of the Internet of Things.

Description

TECHNICAL FIELD

[0001] The present application relates to a backfire antenna with broadband and beam equalization characteristics, belonging to the field of antenna and microwave technology and Internet of Things. BACKGROUND

[0002] With the rapid development of wireless communication, backfire antennas have been widely used in television live broadcast, telemetry and remote control, satellite communication, tracking and other aspects. In particular, backfire antennas with E / H plane beam equalization characteristics can be used as the feed source of parabolic reflector antennas. However, conventional backfire antennas with beam equalization characteristics are resonant antennas with narrow impedance bandwidth, so how to simultaneously realize beam equalization and broadband matching characteristics is a challenging problem in the field of backfire antennas. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a backfire antenna with broadband and beam equalization characteristics, which can realize the characteristics of surface beam equalization and broadband matching, thereby being used as the feed source of a parabolic reflector antenna. The antenna has the characteristics of small size, simple structure and low manufacturing cost, and has wide application prospects in various wireless sensing and various radio frequency identification systems of Internet of Things.

[0004] The present application adopts the following technical solutions to solve the above technical problems:

[0005] The present application adopts the following technical solutions to solve the above technical problems: A backfire antenna with broadband and beam equalization characteristics, comprising an elliptical main reflector, a fan-shaped dipole and an elliptical sub-reflector; the elliptical main reflector is located above the fan-shaped dipole, the elliptical sub-reflector is located below the fan-shaped dipole, and the elliptical main reflector and the elliptical sub-reflector are connected by a plastic support column; the fan-shaped dipole is composed of two identical fan-shaped patches, and is perpendicular to the elliptical main reflector and the elliptical sub-reflector, respectively; the fan-shaped dipole has two coaxial cables, one of which is a feeding cable for participating in feeding, and the other of which is a virtual cable for not participating in feeding; the outer conductor of the feeding cable is attached to the right arm of the fan-shaped dipole, and the inner conductor is connected to the left arm of the fan-shaped dipole; the virtual cable is symmetrically attached to the left arm of the fan-shaped dipole and grounded to balance the current on the two arms of the fan-shaped dipole.

[0006] Further, a combination of branches and slots is provided on the fan-shaped dipole to tune its working mode.

[0007] Further, a rectangular slot and a tuning branch are respectively provided on each of the fan-shaped patches, the two rectangular slots are the same and symmetric about the central axis of the fan-shaped dipole, and the two tuning branches are the same and symmetric about the central axis of the fan-shaped dipole.

[0008] Further, the two tuning stubs are located in the same plane as the fan-shaped dipole.

[0009] Further, the long axis radius of the elliptical main reflector ranges from 0.6 wavelength to 0.9 wavelength, and the ratio of the short axis to the long axis ranges from 0.25 to 0.75.

[0010] Further, the radius of the fan-shaped patch ranges from 0.2 wavelength to 0.3 wavelength.

[0011] Further, the central angle of the fan-shaped patch ranges from 260° to 340°.

[0012] Further, the length of the tuning stub ranges from 0.2 wavelength to 0.3 wavelength, and the width ranges from 0.03 wavelength to 0.06 wavelength.

[0013] Further, the length of the rectangular slot ranges from 0.07 wavelength to 0.09 wavelength, and the width ranges from 0.01 wavelength to 0.02 wavelength.

[0014] Compared with the prior art, the above technical scheme has the following technical effects: the present application can realize beam equalization and wideband matching characteristics, and can be used as a feed source of a parabolic reflector antenna. The antenna has the characteristics of small volume, simple structure, low manufacturing cost, etc., and has a wide application prospect in various wireless sensing and various radio frequency identification systems of the Internet of Things. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a front structure of the antenna and a reference coordinate diagram;

[0016] Figure 2 is a three-dimensional perspective view of the antenna and a reference coordinate diagram;

[0017] Figure 3 is the reflection coefficient characteristics of an antenna with an elliptical long axis of 98mm, a central angle of 300°, and a radius of 31mm calculated by HFSS software;

[0018] Figure 4 is the normalized radiation pattern of the zx plane of the antenna with an elliptical long axis of 98mm, a central angle of 300°, and a radius of 31mm calculated by HFSS software;

[0019] Figure 5 is the normalized radiation pattern of the zy plane of the antenna with an elliptical long axis of 98mm, a central angle of 300°, and a radius of 31mm calculated by HFSS software;

[0020] Figure 6is the reflection coefficient characteristic of the antenna with an ellipse long axis of 95mm, a central angle of 290° and a radius of 30mm calculated by HFSS software;

[0021] Figure 7 is the normalized radiation pattern of the zx plane of the antenna with an ellipse long axis of 95mm, a central angle of 290° and a radius of 30mm calculated by HFSS software;

[0022] Figure 8 is the normalized radiation pattern of the zy plane of the antenna with an ellipse long axis of 95mm, a central angle of 290° and a radius of 30mm calculated by HFSS software;

[0023] In the figure, 1 is an elliptical main reflector, 2 is a fan-shaped dipole, 3, 3' are tuning branches, 4 is a feeding cable, 4' is a virtual cable, 5 is an inner conductor of a coaxial cable, 6 is a central angle, 7, 7' are rectangular slots, 8 is a plastic support column, and 9 is an elliptical sub-reflector. DETAILED DESCRIPTION

[0024] The technical solutions of the present application will be further described in detail below with reference to the accompanying drawings:

[0025] The present application provides a backfire antenna with broadband and beam equalization characteristics, as shown in Figure 1 , Figure 2 which comprises an elliptical main reflector 1, a fan-shaped dipole 2 and an elliptical sub-reflector 9; the elliptical main reflector 1 is located above the fan-shaped dipole 2, the elliptical sub-reflector 9 is located below the fan-shaped dipole 2, and the elliptical main reflector 1 and the elliptical sub-reflector 9 are connected by a plastic support column 8; the fan-shaped dipole 2 is composed of two identical fan-shaped patches, and is perpendicular to the elliptical main reflector 1 and the elliptical sub-reflector 9, respectively.

[0026] There are two coaxial cables on the fan-shaped dipole 2, one of which is a feeding cable 4 that participates in feeding, and the other is a virtual cable 4' that does not participate in feeding; the outer conductor of the feeding cable 4 is attached to the right arm of the fan-shaped dipole 2, and the inner conductor 5 is connected to the left arm of the fan-shaped dipole 2; the virtual cable 4' is symmetrically attached to the left arm of the fan-shaped dipole 2 and grounded to balance the current on the two arms of the fan-shaped dipole 2.

[0027] In specific implementation, the major and minor axes of the elliptical main reflector 1 and the elliptical sub-reflector 9 can be changed, and the radius and central angle of the fan-shaped dipole 2 can be changed.

[0028] In one embodiment, a combination of branches and slots is provided on the fan-shaped dipole 2 to tune its operating mode.

[0029] In one embodiment, a rectangular slot is arranged on each sector patch, respectively, and the two rectangular slots are identical and symmetrical about the central axis of the sector dipole 2. Moreover, the length and width of the rectangular slot can be changed.

[0030] In one embodiment, a tuning stub is arranged on each sector patch 2, respectively, and the two tuning stubs are identical and symmetrical about the central axis of the sector dipole 2. Moreover, the tuning stub is located in the same plane as the sector dipole 2, and the length and width of the tuning stub can be changed.

[0031] In one embodiment, the major axis of the elliptical main reflector 1 is 98 mm, the minor axis is 49 mm, and the ratio of the minor axis to the major axis is 0.5. The radius of the sector dipole 2 is 31 mm, and the central angle is 300°. The length of the tuning stub is 26.9 mm, and the width is 5.8 mm. The length of the rectangular slot is 9.8 mm, and the width is 1.5 mm. The antenna characteristics calculated by using the HFSS software are as follows: Figure 3 is the reflection coefficient characteristic of the antenna calculated by using the HFSS software. The impedance bandwidth of the antenna covers the frequency band of 1.63-3.31 GHz, the center frequency is 2.47 GHz, and the relative bandwidth is about 68%. It can be seen that the antenna has a relatively wide impedance bandwidth. Figure 4 is the normalized radiation pattern of the antenna on the zox plane calculated by using the HFSS software. The solid line represents the main polarization, and the dashed line represents the cross polarization. It can be seen that the 3dB beam width of the antenna is about 60°. Figure 5 is the normalized radiation pattern of the antenna on the zoy plane calculated by using the HFSS software. The solid line represents the main polarization, and the dashed line represents the cross polarization. It can be seen that the 3dB beam width of the antenna is about 70°. Through simulation, the frequency band in which the beam is equalized is 1.7 GHz-2.6 GHz.

[0032] In one embodiment, the major axis of the elliptical main reflector 1 is 95 mm, the minor axis is 47.5 mm, and the ratio of the minor axis to the major axis is 0.5. The radius of the sector dipole 2 is 30 mm, and the central angle is 290°. The length of the tuning stub is 26.9 mm, and the width is 5.8 mm. The length of the rectangular slot is 9.8 mm, and the width is 1.5 mm. The antenna characteristics calculated by using the HFSS software are as follows: Figure 6 is the reflection coefficient characteristic of the antenna calculated by using the HFSS software. The impedance bandwidth of the antenna covers the frequency band of 1.67-3.36 GHz, the center frequency is 2.515 GHz, and the relative bandwidth is about 67.2%. It can be seen that the antenna has a relatively wide impedance bandwidth. Figure 7 is the normalized radiation pattern of the antenna on the zox plane calculated by using the HFSS software. The solid line represents the main polarization, and the dashed line represents the cross polarization. It can be seen that the 3dB beam width of the antenna is about 60°.Figure 8 is the normalized radiation pattern of the antenna in the zoy plane calculated by HFSS software, the solid line represents the main polarization, and the dashed line represents the cross polarization. It can be seen that the 3dB beam width of the antenna is about 70°. Through simulation, the frequency band in which beam equalization is finally achieved is 1.7GHz-3.1GHz.

[0033] According to the comparative embodiment, two cases are simulated according to different long and short axes, central angles and radii, that is, the long axis is 98mm, the central angle is 300° and the radius is 31mm, and the long axis is 95mm, the central angle is 290° and the radius is 30mm. It is found that both the two schemes can achieve the characteristics of beam equalization and wideband matching.

[0034] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless otherwise defined.

[0035] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can understand and think of the transformation or replacement within the technical range disclosed by the present application, which should be covered in the inclusive scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A backfire antenna having broadband and beam equalization characteristics, comprising: The antenna comprises an elliptical main reflector (1), a fan-shaped dipole (2) and an elliptical sub-reflector (9). The elliptical main reflector (1) is located above the fan-shaped dipole (2), and the elliptical sub-reflector (9) is located below the fan-shaped dipole (2), and the elliptical main reflector (1) and the elliptical sub-reflector (9) are connected by plastic support columns (8). The fan-shaped dipole (2) is composed of two identical fan-shaped patches, and is perpendicular to the elliptical main reflector (1) and the elliptical sub-reflector (9) respectively. There are two coaxial cables on the fan-shaped dipole (2), one of which is a feed cable (4) that participates in feeding, and the other is a virtual cable (4') that does not participate in feeding; the outer conductor of the feed cable (4) is attached to the right arm of the fan-shaped dipole (2), and the inner conductor (5) is connected to the left arm of the fan-shaped dipole (2); the virtual cable (4') is symmetrically attached to the left arm of the fan-shaped dipole (2) and grounded to balance the current on the two arms of the fan-shaped dipole (2).

2. A backfire antenna with wideband and beam equalization characteristics according to claim 1, characterized in that, A combination of branches and slots is provided on the fan-shaped dipole (2) to tune its working mode.

3. A backfire antenna with wideband and beam equalization characteristics according to claim 2, characterized in that, A rectangular slot and a tuning branch are respectively provided on each of the fan-shaped patches, and the two rectangular slots are the same and symmetric about the central axis of the fan-shaped dipole (2), and the two tuning branches are the same and symmetric about the central axis of the fan-shaped dipole (2).

4. A backfire antenna with wideband and beam equalization characteristics according to claim 3, characterized in that, The two tuning branches and the fan-shaped dipole (2) are located in the same plane.

5. A backfire antenna with wideband and beam equalization characteristics according to claim 1, characterized in that, The major axis radius of the elliptical main reflector (1) ranges from 0.6 to 0.9 wavelengths, and the ratio of the minor axis to the major axis ranges from 0.25 to 0.

75.

6. A backfire antenna with wideband and beam equalization characteristics according to claim 1, characterized in that, The radius of the fan-shaped patch ranges from 0.2 to 0.3 wavelengths.

7. A backfire antenna with wideband and beam equalization characteristics according to claim 1, characterized in that, The central angle (6) of the fan-shaped patch ranges from 260° to 340°.

8. A backfire antenna with wideband and beam equalization characteristics according to claim 3, characterized in that, The length of the tuning branch (3, 3') ranges from 0.2 to 0.3 wavelengths, and the width ranges from 0.03 to 0.06 wavelengths.

9. A backfire antenna with wideband and beam equalization characteristics according to claim 3, characterized in that, The length of the rectangular slot (7, 7') ranges from 0.07 to 0.09 wavelengths, and the width ranges from 0.01 to 0.02 wavelengths.

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