Ultra-wideband low-profile vertical polarization omnidirectional antenna applied to indoor subsystem
Technical Field
The invention particularly relates to the technical field of antennas, in particular to an ultra-wideband low-profile vertically polarized omnidirectional antenna applied to a room subsystem.
Background
In current mobile communication, there is an increasing demand for indoor base stations, and indoor communication has become one of the main communication scenarios of daily life. Wherein, the omni-directional antenna capable of realizing 360 degrees of signal full coverage is the first choice of indoor base station. As 5G is beginning to be commercially available on a large scale, the use of 5G antennas is becoming widespread. Meanwhile, the 2G/3G/LTE frequency band still plays an important role in the evolution process of the communication technology. Therefore, the development of the antenna which simultaneously covers the frequency bands of 2G/3G/LTE/5G has good application prospect. The frequency band of 1.7-2.7 GHz is an important application of a 4G LTE (long-term evolution) network, and is of great interest in the design of base station antennas. In addition, N78 (3.3-3.8 GHz) and N79 (4.8-5 GHz) are the primary frequency bands for 5G communication deployment and testing. Because the indoor distributed omnidirectional antenna is arranged on the indoor ceiling, the lower section is beneficial to saving space and is more attractive. Therefore, there is an urgent need for a low profile indoor distribution antenna capable of simultaneously covering the three frequency bands.
Conventional indoor distributed omni-directional antennas are largely classified into single polarized omni-directional antennas and dual polarized omni-directional antennas, which are generally based on vertical polarization, because vertical polarized waves are more likely to propagate on undulating terrain in land mobile communication, thereby greatly reducing energy attenuation. At present, the vertical polarization antenna is mostly realized by a monopole antenna or a conical antenna, and has large section size and high production and manufacturing cost. Furthermore, for ultra wideband omni-directional antennas, prescription pattern degradation at high frequencies is a common problem.
The Chinese patent No. 109687132A discloses a low-profile vertically polarized ultra-wideband omni-directional antenna, which comprises: the circuit comprises a plurality of triangular metal sheets, short circuit metal columns, round metal sheets, rectangular grounding plates and coaxial feed parts. The cross-sectional height of the vertically polarized omnidirectional antenna is 0.128λ low (λ low For wavelengths in free space at the lowest operating frequency of the antenna), at high frequency points, the horizontal plane pattern is severely degraded, with out-of-roundness greater than 5dB.
Disclosure of Invention
The invention aims at: the defects of the prior art are overcome, the ultra-wideband low-profile vertical polarization omnidirectional antenna applied to the indoor subsystem is provided, and the problems that the conventional ultra-wideband vertical polarization omnidirectional antenna is large in profile size and the prescription pattern of a high-frequency point is deteriorated are effectively solved.
The invention provides an ultra-wideband low-profile vertical polarization omnidirectional antenna applied to a room subsystem, which comprises a metal disc, a radiation arm and a metal floor, wherein an SMA head is inserted upwards from a central hole of the metal floor, an inner conductor of the SMA head is connected with an inner end of the radiation arm, an outer conductor of the SMA head is connected with the metal floor, and the metal disc is supported above the metal floor through a radiation arm support in an empty space, and the ultra-wideband low-profile vertical polarization omnidirectional antenna is characterized in that: the radiation arms comprise long straight radiation arms and wave-folded radiation arms which are alternately arranged in a radial shape; the outer end of the long straight radiation arm is fixedly connected with the metal disc; the top of the wave-folding type radiation arm is fixedly connected with the metal disc, the bottom of the outer end of the wave-folding type radiation arm is connected with the metal floor, and the part inside the outer end of the wave-folding type radiation arm is suspended above the metal floor.
The invention is applied to an ultra-wideband low-profile vertical polarization omnidirectional antenna of a room subsystem, the combination of the wave-folded radiation arm and the metal disc at the top reduces the height of the antenna to meet the application requirement of low profile, and the profile height is only 5.4% of the vacuum wavelength at the lowest working frequency; the long straight radiation arm can generate a resonance point at a high-frequency point, and the resonance point is combined with the resonance point generated by the wave-folded radiation arm, so that the bandwidth of the antenna is expanded; the radiating arms also act as support members for the top metal disc.
Six arc-shaped grooves are etched on the metal floor, so that the problem of radiation performance deterioration of the ultra-wideband antenna at a high frequency point can be solved, and the stability of a directional diagram of the antenna in the whole working frequency band is ensured; the outermost end of the metal floor is bent upward and inward, so that the planar size of the antenna can be reduced while realizing a low profile and without affecting the performance of the antenna.
Furthermore, the invention also claims an antenna, characterized in that: the ultra-wideband low-profile vertically polarized omnidirectional antenna comprises the ultra-wideband low-profile vertically polarized omnidirectional antenna applied to a room subsystem.
Drawings
Fig. 1 is a perspective view of an ultra-wideband low-profile vertically polarized omnidirectional antenna for use in a room subsystem in accordance with the present invention;
fig. 2 is a front view of an ultra-wideband low-profile vertically polarized omnidirectional antenna for use in a chamber subsystem in accordance with the present invention;
fig. 3 is a top view of a metal floor of an ultra-wideband low-profile vertically polarized omnidirectional antenna for use in a room subsystem in accordance with the present invention;
FIG. 4 is a graph of reflection coefficient and gain for an ultra-wideband low profile vertically polarized omnidirectional antenna for use in a chamber subsystem in accordance with the present invention;
fig. 5 is a diagram of an ultra-wideband low-profile vertically polarized omnidirectional antenna at a frequency of 2.2GHz for use in a indoor subsystem in accordance with the present invention;
fig. 6 is a diagram of an ultra-wideband low-profile vertically polarized omnidirectional antenna at a frequency of 3.5GHz for use in a indoor subsystem in accordance with the present invention;
fig. 7 is a diagram of an ultra-wideband low-profile vertically polarized omnidirectional antenna at a frequency of 4.8GHz for use in a indoor subsystem in accordance with the present invention;
in the drawings, 1-a metal disc; 2-radiating arms; 3-metal floor; 21-corrugated metal arms; 22-long straight metal arms; 31-arc grooves; 32-central aperture.
Detailed Description
The invention is further explained in the following detailed description with reference to the drawings so that those skilled in the art can more fully understand the invention and can practice it, but the invention is explained below by way of example only and not by way of limitation.
Referring to fig. 1 to 3, which are perspective views showing the structure of an ultra wideband low profile vertically polarized omnidirectional antenna applied to a room subsystem according to the present invention, the antenna comprises a metal disc 1, a radiation arm 2 and a metal floor 3, an SMA head is inserted upward from a central hole 32 of the metal floor 3, an inner conductor of the SMA head is connected to an inner end of the radiation arm 2, an outer conductor of the SMA head is connected to the metal floor 3, and the metal disc 1 is supported overhead above the metal floor 3 by the radiation arm 2. The metal disc 1 and the metal floor 3 are circular in shape, and the centers of the two circles are positioned on the same vertical line. The central hole 32 of the metal floor 3 is provided with a feed port through which the SMA head is fixed. The metal disc 1, the radiation arm 2 and the metal floor 3 are made of copper, and form an integral structure through a 3D printing technology.
In the present embodiment, the radiation arm 2 includes three long straight radiation arms 22 and three wave-folded radiation arms 21. Wherein the long straight radiating arms 22 and the wave-folding radiating arms 21 are alternately arranged in a radial shape, and the included angle between the adjacent long straight radiating arms 22 and the wave-folding radiating arms 21 is 60 degrees. The outer end of the long straight radiating arm 22 is upwarped and fixedly connected with the metal disc 1, and the inner end of the long straight radiating arm 22 is connected with the inner conductor of the SMA head. The long straight radiating arm 22 is used to create a resonance point at the high frequency point to extend the antenna bandwidth. The corrugated radiating arm 21 is formed by bending a rectangular metal sheet several times, and the number of times and the angle of bending can be adjusted according to the antenna performance (antenna impedance matching). The top of the wave-folded radiating arm 21 is fixedly connected with the metal disc 1, the bottom of the outer end of the wave-folded radiating arm 21 is connected with the metal floor 3, the inner end of the wave-folded radiating arm 21 is connected with the inner conductor of the SMA head, and the part inside the outer end of the wave-folded radiating arm 21 is suspended above the metal floor 3, namely a gap is formed between the bottom of the part inside the outer end of the wave-folded radiating arm 21 and the metal floor 3.
As shown in fig. 1, a metalThe floor 3 is provided with six arc grooves 31, and arc grooves 31 are located the outside of radiation arm 2 in one-to-one correspondence, and the centre of a circle of arc groove 31 and the centre of a circle of metal floor 3 are located same plumb line. The six arc-shaped grooves 31 can effectively solve the problem of radiation performance degradation of the ultra-wideband antenna at a high frequency point, thereby ensuring the stability of the antenna pattern in the whole working frequency band. The outermost end of the metal floor 3 is bent upward and inward for reducing the planar size of the antenna to 0.82λ low (λ low Wavelength in free space at the lowest operating frequency of the antenna).
The metal disc 1 prolongs the current path on the radiating arm 2, and the three corrugated radiating arms 21 are combined with the metal disc 1, so that the antenna section height is reduced; three long straight radiating arms 22 are used to create a resonance point at the high frequency point to extend the antenna bandwidth. The cross-sectional dimension of the antenna is only 0.054λ low The defect of large cross section size commonly existing in the existing similar antennas is overcome to a great extent.
The embodiment of the invention optimizes the size of each part of the antenna, and the specific parameters of the antenna are shown in the following table:
parameters (parameters)
|
r
1
|
r
2
|
r
3
|
r
4
|
t
|
l
1
|
l
2
|
Value of
|
32.30mm
|
73.21mm
|
9.96mm
|
35.06mm
|
0.8mm
|
27.79mm
|
28.92mm
|
Parameters (parameters)
|
w
1
|
w
2
|
w
3
|
h
1
|
h
2
|
h
3
|
α
|
Value of
|
1.43mm
|
2.10mm
|
5.02mm
|
4.93mm
|
3.954mm
|
1.90mm
|
37.43° |
In the table of the present invention,r 1 is the radius of the metal disc 1,r 2 is the radius of the metal floor 3,r 3 is the width of the inward bend of the metal floor 3,r 4 the distance of the arc-shaped groove 31 from the center, t is the thickness of the metal disc 1 and the metal floor 3,l 1 for the projected length of the corrugated radiating arm 21,l 2 for the projected length of the long straight radiating arm 22,w 1 for the width of the corrugated radiating arm 21,w 2 is the width of the long straight radiating arm 22,w 3 is the width of the arcuate slot 31,h 1 for the distance between the metal disc 1 and the metal floor 3,h 2 at a height where the metal floor 3 is upwardly bent,h 3 for the distance between the bottom of the inner end of the corrugated radiating arm 21 and the metal floor 3,αis the angle of the arcuate slot 31. Further, the thickness of the corrugated radiating arm 21 was 1.91mm, and the thickness of the long straight radiating arm 22 was 1.78mm.
Fig. 4 shows a reflection coefficient and gain curve diagram of an ultra-wideband low-profile vertically polarized omnidirectional antenna applied to a room subsystem, and the result shows that the relative bandwidth of the design is 105.22% (1.68-5.41 GHz), and the gain in the working frequency band is between 3.8dBi and 8 dBi.
Fig. 5, 6 and 7 show the radiation pattern of the antenna at three different frequency points. The result shows that the directional diagram of the design in the working frequency band has good consistency, particularly at a high frequency point, the directional diagram also has good omnidirectionality, and the omnidirectional radiation performance in the whole working frequency band is good.
In addition, the invention also discloses an antenna, which comprises the ultra-wideband low-profile vertical polarization omnidirectional antenna applied to the indoor subsystem.
While the foregoing is directed to embodiments of the present invention, other and further details of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.