A broadband high-gain filtering cavity antenna applied to 5G millimeter wave

Abstract

The application discloses a broadband high-gain filter-backed cavity antenna applied to 5G millimeter waves, comprising a metal cavity, the metal cavity comprising a radiation layer, a support layer and a floor layer, one side of the radiation layer away from the floor layer being provided with a slit, the inside of the metal cavity being a first sub-cavity and a second sub-cavity stacked, a first metal column being arranged in the first sub-cavity, and the radiation layer and the floor layer being connected through a probe.The application integrates an antenna with linear polarization normal radiation characteristics and an antenna with broadband filtering characteristics together, adopts a back cavity slot antenna structure, and realizes the characteristics of antenna broadband, filtering, high gain, normal radiation and suppression of backward radiation.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of antennas, in particular to a wideband high-gain filter-backed cavity antenna applied to 5G millimeter waves. BACKGROUND

[0002] In recent years, the speed of communication technology update iteration far exceeds people's expectations, and the resulting is the large popularity of various terminal devices and the increasingly large demand for spectrum by the mobile communication industry, and the original low-frequency spectrum resources have become increasingly tight. Under the condition of limited wireless spectrum resources, it is very difficult to further improve the spectrum utilization and thus improve the system capacity, so in the process of finding new solutions, millimeter wave band has become a popular coping approach because it has more optional frequencies and more available bandwidth. However, millimeter wave space loss, surface wave loss, and small device size require high processing precision, which also puts forward more stringent conditions for the radio frequency front-end system.

[0003] In the application of 5G millimeter wave communication, the frequency spectrum resources are divided into FR1 and FR2: FR1 is the low-frequency part, the frequency band is 450MHz-6000MHz, so it is generally called Sub-6G; FR2 is the high-frequency part, the frequency band is 24.25GHz-52.6GHz, generally called millimeter wave frequency band. Because the existing low-frequency communication technology is relatively mature and the cost is relatively low, it is convenient for rapid large-scale deployment, so China currently takes Sub-6G as the main application frequency band of 5G. However, the millimeter wave frequency band has its unique advantages: absolute bandwidth advantage, that is, absolute channel capacity advantage; the short wavelength of the millimeter wave band means that the antenna unit has a smaller size; at the same time, there is basically no interference source in the millimeter wave band, and the cleaner spectrum resources mean lower bit error rate. The existing millimeter wave filter antenna has the problems of complex structure, large dielectric loss and narrow bandwidth. How to improve the wideband characteristics of the antenna without increasing the structural complexity is also a difficulty in the design of millimeter wave filter antennas. SUMMARY

[0004] The present application relates to the field of antennas, in particular to a wideband high-gain filter-backed cavity antenna applied to 5G millimeter waves.

[0005] Technical solution: A kind of broadband high gain filter back cavity antenna applied to 5G millimeter wave of the present application, including metal cavity, the metal cavity includes radiation layer, support layer and floor layer, the radiation layer is the first surface layer of the metal cavity, the floor layer is the second surface layer of the metal cavity, the support layer is the third surface layer of the metal cavity, one side of the radiation layer away from the floor layer is equipped with slit, the inside of the metal cavity is the first sub-cavity and the second sub-cavity of lamination, the first sub-cavity is close to the radiation layer, the second sub-cavity is close to the floor layer, first metal column is arranged in the first sub-cavity, the radiation layer and the floor layer are connected by probe.

[0006] Further, the slit is L-shaped, and the number of the slit is 2, symmetrically arranged on the radiation layer.

[0007] Further, the center of the first metal column is arranged on the symmetry axis of the two slits.

[0008] Further, the first sub-cavity is provided with a second metal column at the edge position, and the number of the second metal column is 2, symmetrically arranged on the two sides of the first metal column.

[0009] Further, the radiation layer is provided with a first through hole, and the probe is connected to the radiation layer through the first through hole, and the diameter of the first through hole is the same as the diameter of the probe.

[0010] Further, the floor layer is provided with a second through hole, and the diameter of the second through hole is greater than the diameter of the probe, and the center of the second through hole overlaps the center of the probe, and the center is on the symmetry axis.

[0011] Further, the first sub-cavity and the second sub-cavity are communicated.

[0012] Beneficial effect: Compared with the prior art, the present application has the following advantages:

[0013] 1、The present application integrates linear polarization normal radiation characteristic antenna and broadband filter characteristic antenna by reasonably arranging the structure of metal cavity surface and interior, adopts back cavity slot antenna structure, greatly reduces the design complexity of filter antenna, realizes the characteristics of antenna broadband, filtering, high gain, normal radiation and suppression of backward radiation;

[0014] 2、For the wideband filtering antenna, the application realizes the wideband filtering characteristic by introducing the metal column and the resonant slot, the first metal column is used to couple the base mode and the high-order mode resonant frequency of the cavity to the adjacent frequency range, so as to introduce two in-band resonant frequency points; the second metal column arranged on both sides in the first sub-cavity is used to suppress the high-order mode of the cavity out of the band; the L-shaped resonant slot is opened in the radiation layer, the length of the radiation slot is prolonged, the half-wavelength resonant slot is introduced, the third resonant point in the frequency band is generated, so as to expand the impedance bandwidth of the antenna; the electric coupling and the magnetic coupling between the three resonant modes are generated, so as to generate two out-of-band zero points, so as to realize the filtering characteristic of the antenna;

[0015] 3、For the high-gain antenna, the application suppresses the backward radiation of the antenna through the back cavity slot structure;

[0016] 4、The application introduces the symmetrical L-shaped resonant slot in the metal radiation layer, so that the overall weight of the metal frame of the antenna is reduced; meanwhile, the effective radiation area of the antenna is increased, and high gain is realized. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the wideband high-gain filtering back cavity antenna;

[0018] Figure 2 It is a front view of the wideband high-gain filtering back cavity antenna;

[0019] Figure 3 It is a top view of the wideband high-gain filtering back cavity antenna;

[0020] Figure 4 It is a full-band return loss simulation result of the wideband high-gain filtering back cavity antenna;

[0021] Figure 5 It is a gain-frequency variation curve simulation result of the wideband high-gain filtering back cavity antenna;

[0022] Figure 6 It is a radiation pattern of the Theta direction gain component and the Phi direction gain component of the antenna at Phi=90 degrees and the frequency of 24.8 GHz;

[0023] Figure 7 It is a radiation pattern of the Theta direction gain component and the Phi direction gain component of the antenna at Phi=0 degrees and the frequency of 24.8 GHz;

[0024] Figure 8 It is a radiation pattern of the Theta direction gain component and the Phi direction gain component of the antenna at Phi=90 degrees and the frequency of 26.8 GHz;

[0025] Figure 9Radiation pattern for the Theta directional gain component and the Phi directional gain component of the antenna at a frequency of 26.8 Ghz at Phi = 0 degrees;

[0026] Figure 10 Radiation pattern for the Theta directional gain component and the Phi directional gain component of the antenna at a frequency of 28.6 Ghz at Phi = 90 degrees;

[0027] Figure 11 Radiation pattern for the Theta directional gain component and the Phi directional gain component of the antenna at a frequency of 28.6 Ghz at Phi = 0 degrees. DETAILED DESCRIPTION

[0028] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the drawings and embodiments.

[0029] Figures 1-3 A schematic diagram of a wideband high-gain filter-backed cavity antenna structure applied to 5G millimeter waves is shown in the embodiment. The antenna includes a metal cavity 1, which includes a radiation layer 4, a support layer 5 and a floor layer 6. The radiation layer 4 is a first surface layer of the metal cavity 1. The floor layer 6 is a second surface layer of the metal cavity 1. The support layer 5 is a third surface layer of the metal cavity 1. A gap 7 is provided on the side of the radiation layer 4 away from the floor layer 6. The inside of the metal cavity 1 is a first sub-cavity 8 and a second sub-cavity 9 stacked together. The first sub-cavity 8 is close to the radiation layer 4. The second sub-cavity 9 is close to the floor layer 6. A first metal column 2 is arranged in the first sub-cavity 8. The radiation layer 4 and the floor layer 6 are connected by a probe 10.

[0030] Specifically, the first surface layer is the upper surface layer of the metal cavity 1. The second surface layer is the lower surface layer of the metal cavity 1. The third surface layer is the four wall surface layer of the metal cavity 1.

[0031] Preferably, the gap 7 provided on the surface of the radiation layer 4 is L-shaped. The number of gaps 7 is 2. The two L-shaped gaps are symmetrically arranged on the radiation layer 4. The symmetry axis of the two L-shaped gaps is a center line of the radiation layer 4. Further, the long side of the L-shaped gap is on the other center line of the radiation layer 4, as shown in the figure. Figure 3

[0032] Further, the first metal column 2 is arranged in the first sub-cavity 8. The center of the first metal column 2 is arranged on the symmetry axis of the two L-shaped gaps, which is also the center line of the first sub-cavity 8. Preferably, the first metal column can be a cylindrical or cuboid.

[0033] ​Further, the first sub-cavity 8 is provided with a second metal column 3 near the edge, and the number of the second metal column 3 is 2, which is symmetrically arranged on both sides of the first metal column 2.

[0034] Further, the radiation layer 4 is provided with a first through hole 11 as a feeding hole, and the probe 10 connects the radiation layer 4 and the floor layer 6 through the first through hole 11, and the diameter of the first through hole 11 is the same as that of the probe 10. The center of the first through hole 11 is on the symmetry axis of the two L-shaped slots.

[0035] Further, the floor layer 6 is provided with a second through hole 12, the diameter of the second through hole 12 is larger than that of the probe 10, and the center of the second through hole 12 overlaps with that of the probe 10, and the center is on the symmetry axis of the L-shaped slot.

[0036] Further, the first sub-cavity 8 and the second sub-cavity 9 are in communication.

[0037] From the above description, it can be seen that the antenna in the embodiment excites multiple resonance modes in the cavity through the probe to expand the bandwidth; the symmetric L-shaped slot is arranged near the first through hole, so that the resonance frequency of the half-wavelength resonance mode of the slot is in the passband, and the first metal column and the second metal column are combined to realize high gain, high bandwidth and high filtering characteristics; the first metal column drags the fundamental mode resonance frequency of the cavity to high frequency, which is excited together with the half-wavelength resonance mode of the L-shaped slot and the high-order mode of the cavity, thereby realizing wide bandwidth. In addition, electromagnetic coupling is introduced between different resonance modes to realize two radiation zeros, and the second metal column is used to suppress the high-order mode outside the band in the embodiment, thereby improving the out-of-band suppression capability; the antenna in the embodiment realizes high gain, high bandwidth and high filtering characteristics, and can be applied to 5G frequency band mobile communication, space communication and other working equipment.

[0038] In one embodiment, in order to verify the effectiveness of the above-mentioned wideband high-gain filtering back cavity antenna for 5G millimeter wave, the following structure size is taken as an example for description:

[0039] As shown in Figures 1-3 the above-mentioned wideband high-gain filtering back cavity antenna applied to 5G millimeter wave, comprising a metal cavity 1, the metal cavity 1 comprises a radiation layer 4, a support layer 5 and a floor layer 6, the radiation layer 4 is a first surface layer of the metal cavity 1, the floor layer 6 is a second surface layer of the metal cavity 5, the support layer 5 is a third surface layer of the metal cavity 1, one side of the radiation layer 4 away from the floor layer 6 is provided with a slot 7, the inside of the metal cavity 1 is a first sub-cavity 8 and a second sub-cavity 9 stacked, the first sub-cavity 8 is close to the radiation layer 4, the second sub-cavity 9 is close to the floor layer 6, the first sub-cavity 8 is provided with a first metal column 2, and the radiation layer 4 and the floor layer 6 are connected through a probe 10.

[0040] The upper surface of the radiation layer 4 is a rectangle with a width of 8.3 mm and a length of 13.9 mm. The thickness of the radiation layer 4 is 0.2 mm, the total thickness of the first sub-cavity 8 and the second sub-cavity 9 is 1.9 mm, and the thickness of the floor layer 6 is 0.2 mm. The long side of the L-shaped slot has a length of 5.2 mm and a width of 1.2 mm, and the short side has a length of 1.7 mm and a width of 0.5 mm. The first metal column 2 has a width of 0.4 mm, a length of 1 mm, and a height of 0.9 mm. The second metal column 3 has a width of 0.4 mm, a length of 1.7 mm, and a height of 0.9 mm. The first through hole 11 has a diameter of 0.64 mm, the second through hole 12 has a diameter of 1.67 mm, and the probe 10 has a diameter of 0.64 mm.

[0041] Figure 4 The antenna S 11 The simulation results of the antenna parameters show that the impedance bandwidth (return loss <-10 dB) of the antenna is 17.9% (24.4 GHz-29.2 GHz), and there are three in-band resonance frequency points at 24.8 GHz, 26.8 GHz and 28.6 GHz.

[0042] Figure 5 The simulation results of the antenna gain show that the maximum gain that can be achieved in the passband is 9.3 dBi, and a relatively high gain can be achieved. Two radiation zeros appear at 23.4 GHz and 31.2 GHz near the passband, which makes the antenna have good gain drop and achieves good filtering characteristics.

[0043] Figures 6-11 The normalized radiation patterns of the antenna in the Phi=90° (yoz plane) and Phi=0° (xoz plane) at the frequencies of 24.8 GHz, 26.8 GHz and 28.6 GHz are shown in the figures. As can be seen from the figures, the main radiation direction of the antenna is normal, the backward radiation suppression is good, and the main polarization and cross polarization levels are more than 20 dB.

[0044] The antenna greatly simplifies the design complexity of the millimeter wave antenna, and realizes the integration of wideband, filtering and high gain into a unified metal cavity structure. The radiation operating frequency band of the antenna is 24.4-29.2 GHz. For the design of the millimeter wave wideband filtering antenna, a slot is opened near the feed in the top layer of the rectangular metal cavity, thereby exciting the half-wavelength resonance mode of the slot to produce a resonance point within a frequency range, and by loading metal columns in the metal cavity, the resonance frequencies of the base mode and high-order modes of the resonant cavity are coupled into the same frequency band, and the high-order resonance modes are suppressed, thereby widening the impedance bandwidth of the antenna and improving the out-of-band suppression. In addition, due to the difference in resonance modes, a mixed coupling mode is introduced, thereby producing a radiation zero point to achieve filtering characteristics.

Claims

1. A wideband high-gain filtered cavity antenna applied to 5G millimeter wave, characterized in that, The metal cavity comprises a radiation layer, a support layer and a floor layer, the radiation layer is a first surface layer of the metal cavity, the floor layer is a second surface layer of the metal cavity, the support layer is a third surface layer of the metal cavity, the radiation layer is provided with a gap on the side away from the floor layer, the inside of the metal cavity is a first sub-cavity and a second sub-cavity which are stacked, the first sub-cavity is close to the radiation layer, the second sub-cavity is close to the floor layer, a first metal column is arranged in the first sub-cavity, and the radiation layer and the floor layer are connected through a probe; the first sub-cavity is communicated with the second sub-cavity.

2. The antenna according to claim 1, characterized in that, The gap is L-shaped, and the number of the gaps is 2, which are symmetrically arranged on the radiation layer.

3. The antenna according to claim 2, characterized in that, The center of the first metal column is arranged on the symmetry axis of the two gaps.

4. The antenna according to claim 3, characterized in that, The first sub-cavity is provided with a second metal column at the edge position, and the number of the second metal columns is 2, which are symmetrically arranged on the two sides of the first metal column.

5. The antenna according to claim 1, wherein, The radiation layer is provided with a first through hole, the probe is connected to the radiation layer through the first through hole, and the diameter of the first through hole is the same as that of the probe.

6. The antenna according to claim 3, wherein, The floor layer is provided with a second through hole, the diameter of the second through hole is larger than that of the probe, and the center of the second through hole overlaps with that of the probe, and the center is on the symmetry axis.

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