Disclosure of Invention
The invention aims at overcoming the defects of the prior art, and provides a large-scale MIMO antenna so as to realize the convenience of independent detection, maintenance or replacement of an antenna subarray and a calibration network.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a large-scale MIMO antenna comprises a reflecting plate, a calibration network arranged on one side of the reflecting plate, and N x M antenna subarrays arranged on one side of the reflecting plate far away from the calibration network, wherein N is a positive integer greater than or equal to 1, and M is a positive integer greater than or equal to 2; the antenna subarrays and the calibration network are respectively in threaded connection with the reflecting plate through metal screws; the metal screw comprises a first screw and a second screw, the antenna subarrays are detachably connected with the reflecting plate through the first screw, the antenna subarrays are electrically connected with the reflecting plate through the first screw and are in direct current grounding, the calibration network is detachably connected with the reflecting plate through the second screw, and the calibration network is electrically connected with the reflecting plate through the second screw and is in direct current grounding.
Further, the antenna subarray comprises a power dividing plate and a radiation unit arranged on the power dividing plate.
Further, the power dividing plate is of a microstrip line structure.
Further, the power dividing plate comprises a first dielectric layer, a first floor arranged on one side of the first dielectric layer close to the reflecting plate, and a first circuit layer arranged on one side of the first dielectric layer far away from the reflecting plate.
Further, the calibration network is a microstrip line structure or a strip line structure.
Further, the calibration network comprises a second dielectric layer, a third dielectric layer, a second floor arranged on one side of the second dielectric layer close to the reflecting plate, a second circuit layer arranged between the second dielectric layer and the third dielectric layer, and a third floor arranged on one side of the third dielectric layer far away from the second dielectric layer.
Further, the thickness of the reflecting plate is 1.5 mm-3 mm.
Further, the antenna subarrays are connected with a calibration network through probes.
Further, at least one metal screw is arranged around the probe.
Further, the antenna subarrays are provided with first metallized through holes which are used for connecting the antenna subarrays and the reflecting plate around the metal screws, and the calibration network is provided with second metallized through holes which are used for connecting the calibration network and the reflecting plate (2) around the metal screws.
The invention has the beneficial effects that:
1. the radiating unit is divided into the antenna subarrays to form modularization, and each module of the antenna subarrays and the calibration network is suitable for automatic processing of SMT (surface mount technology) technology, so that the consistency and the reliability of production and processing are improved;
2. meanwhile, the modularized antenna subarrays are convenient to detect, maintain or replace independently, and the situation that the whole antenna is scrapped due to the failure of one antenna subarray is avoided, so that the cost is reduced;
3. in addition, at least one metal screw is arranged around the probe to realize direct current grounding of the calibration network or the antenna subarray and the reflecting plate, and the combination of probe feed and the direct current grounding of the metal screw effectively inhibits crosstalk between signals of all radio frequency ports, so that S parameters of all radio frequency ports are improved, the amplitude, phase consistency and linearity of the calibration network are ensured, and radio frequency signals are well transmitted between antenna assemblies;
4. meanwhile, the combination of the probe feed and the direct current grounding of the metal screw ensures the electrical performance and the structural reliability of the antenna, and ensures the structural design to be flexible and the calibration network size design to be optimized.
Drawings
Fig. 1 is a schematic top view of a massive MIMO antenna according to an embodiment of the present invention;
fig. 2 is a schematic cross-sectional structure of a massive MIMO antenna according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a power divider in an embodiment of the present invention;
FIG. 4 is an enlarged view of a portion of the structure around the probe in accordance with an embodiment of the present invention;
FIG. 5 is a graph showing the amplitude deviation test of the calibration port to each RF port in a 4.5G massive MIMO antenna experiment according to one embodiment of the present invention;
FIG. 6 is a chart of phase deviation test from calibration port to each RF port in a 4.5G massive MIMO antenna experiment according to an embodiment of the present invention;
FIG. 7 is a chart showing the test of the homopolar isolation of each RF port in a 4.5G massive MIMO antenna experiment according to one embodiment of the present invention;
FIG. 8 is a chart showing the test of the isolation between different polarizations of each RF port in a 4.5G massive MIMO antenna according to one embodiment of the present invention;
fig. 9 is a chart of standing wave test of a radio frequency port in a 4.5G massive MIMO antenna experiment according to an embodiment of the present invention.
The marks in the figure are as follows: 1-power splitter, 101-first circuit layer, 102-first dielectric layer, 103-first floor, 104-first metallized via, 105-radiating element, 2-reflector, 3-calibration network, 301-second floor, 302-second dielectric layer, 303-second circuit layer, 304-third dielectric layer, 305-third floor, 306-second metallized via, 4-probe, 5-metal screw, 6-plastic rivet.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
In the description of the present invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
In the embodiments of the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like are to be construed broadly and include, for example, either permanently connected, removably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
Referring to fig. 1 and 2, in an embodiment, a massive MIMO antenna is provided, which includes a reflecting plate 2, a calibration network 3 disposed on one side of the reflecting plate 2, and n×m antenna sub-arrays disposed on one side of the reflecting plate 2 away from the calibration network 3, where N is a positive integer greater than or equal to 1, and M is a positive integer greater than or equal to 2. In this embodiment, 4*4 antenna subarrays are provided, that is, 16 antenna subarrays are arranged in 4 rows and 4 columns; the antenna subarrays are fixedly arranged on the front surface of the reflecting plate 2 through metal screws 5; the metal screws 5 realize the electric connection between the antenna subarrays and the reflecting plate 2, so that the direct current grounding of the antenna subarrays and the reflecting plate 2 is realized; in the embodiment, the edge of the antenna subarray is also arranged on a plastic rivet 6 for fixing the antenna subarray on the reflecting plate 2. In the embodiment, the calibration network 3 is fixedly installed on one side, far away from the antenna subarrays, of the reflecting plate 2 through the metal screws 5, and the calibration network 3 is electrically connected with the reflecting plate 2 through the metal screws 5, so that direct current grounding of the calibration network 3 and the reflecting plate 2 is realized; an input port of the calibration network 3 is connected to a radio frequency connector (not shown). In an embodiment, the antenna subarrays are electrically connected to the calibration network 3 by probes 4; one end of the probe 4 is electrically connected with the antenna subarray through welding, and the other end of the probe 4 is electrically connected with the calibration network 3 through welding. In the embodiment, the reflecting plate 2 is provided with a threaded hole for installing a metal screw 5.
In other embodiments, the antenna subarrays may be further arranged in other numbers such as 1*2, 2×2, 2*3, etc. and arranged in a corresponding array; the antenna subarray and the calibration network 3 are fixed on the reflecting plate 2 through metal screws 5, nuts are fixedly arranged on the reflecting plate 2, and the nuts are connected with the metal screws 5 in a matched mode.
Referring to fig. 3, in the embodiment, the antenna subarray includes a power division board 1 and a plurality of radiating elements 105, where the antenna subarray is formed by electrically connecting the plurality of radiating elements 105 on the power division board 1, and the radiating elements 105 are arranged in an array; in this embodiment, the radiation unit 105 is a patch type radiation unit; the power dividing plate 1 is fixedly arranged on the reflecting plate 2 through metal screws 5; the power dividing plate 1 is electrically connected with the calibration network 3 through the probe 4; the radiation unit 105 is arranged at the side of the power dividing plate 1 away from the reflecting plate 2. Referring to fig. 2 and 4, in the embodiment, a metal screw 5 is disposed around the connection position of the power dividing plate 1 and the probe 4, and the metal screw 5 is connected between the power dividing plate 1 and the reflecting plate 2; a plurality of first metallized through holes 104 are formed in the power dividing plate 1 and around the metal screws 5; a metal screw 5 is arranged around the position where the calibration network 3 is connected with the probe 4, and the metal screw 5 is connected between the calibration network 3 and the reflecting plate 2; the calibration network 3 is provided with a plurality of second metallized vias 306 located around the metal screw 5. In an embodiment, the cross-section of the first metallized via 104 and the second metallized via 306 is circular.
In other embodiments, two, three, four or other numbers of metal screws 5 may be disposed around the connection position of the power dividing plate 1 and the probe 4, and the metal screws 5 are connected between the power dividing plate 1 and the reflecting plate 2; a plurality of first metallized through holes 104 are formed in the periphery of the power dividing plate 1, which is positioned on the metal screw 5; the cross-section of the first metallized via 104 may also have other shapes such as oval, rectangular, square, pentagon, etc.
In other embodiments, two, three, four, five or other numbers of metal screws 5 may be disposed around the connection location of the calibration network 3 and the probe 4, and the metal screws 5 are connected between the calibration network 3 and the reflection plate 2; the calibration network 3 is provided with a plurality of second metallized through holes 306 around the metal screw 5; the cross-section of the second metallized via 306 may also have other shapes such as oval, rectangular, square, pentagon, etc.
In other embodiments, the radiating element 105 may be in the form of a conventional die-cast element, a PCB dipole element, a plastic element, or other radiating element; the radiating elements 105 in the antenna subarrays are arranged in a staggered manner.
Referring to fig. 2, in an embodiment, the power dividing board 1 is a microstrip line structure; the power dividing plate 1 comprises a first dielectric layer 102, a first floor 103 arranged on one side of the first dielectric layer 102 close to the reflecting plate 2, and a first circuit layer 101 arranged on one side of the first dielectric layer 102 far away from the reflecting plate 2; the first floor 103 is in contact with the reflective plate 2; the radiation unit 105 is connected with the first circuit layer 101 by welding; the probes 4 are soldered to pads of the first wiring layer 101.
Referring to fig. 2, the calibration network 3 is a strip line structure; the calibration network 3 includes a second dielectric layer 302, a third dielectric layer 304, a second floor 301 disposed on a side of the second dielectric layer 302 close to the reflective plate 2, a second circuit layer 303 disposed between the second dielectric layer 302 and the third dielectric layer 304, and a third floor 305 disposed on a side of the third dielectric layer 304 far from the second dielectric layer 302. In an embodiment, the second dielectric layer 302 is disposed near the reflective plate 2; the second floor 301 is in contact with the reflecting plate 2, the third floor 305 is arranged on one side of the calibration network 3 away from the reflecting plate 2, and the second circuit layer 303 is positioned in the middle layer of the calibration network 3; the probe 4 is soldered to the pad of the second wiring layer 303.
In other embodiments, the calibration network 3 is a microstrip line structure, and the calibration network 3 includes a dielectric layer, a circuit layer disposed on a side of the dielectric layer away from the reflective plate, and a floor disposed on a side of the dielectric layer close to the reflective plate.
In an embodiment, the thickness of the reflecting plate 2 is 1.5mm. In other embodiments, the thickness of the reflecting plate 2 may be other thicknesses from 1.5mm to 3mm, such as 2.1mm, 2.5mm, 2.8mm, and 3mm.
From the above, the antenna subarray is modularized in structure, and the antenna subarray, the calibration network 3 and the reflecting plate 2 are detachably connected, so that each component of the antenna subarray, the reflecting plate 2 and the calibration network 3 is suitable for SMT process automatic processing production, and the consistency and reliability of the processing of each component are greatly improved; meanwhile, the antenna subarrays and the calibration network 3 can be independently detected, maintained or replaced, so that the situation that the whole antenna is scrapped due to the fact that a certain module is in a problem is avoided.
In addition, the feeding is carried out between the calibration network 3 and the antenna subarrays through the probes 4, and at least one metal screw 5 is arranged on the antenna subarrays and the calibration network 3 and is positioned near the probes 4 and used for the direct current grounding of the antenna subarrays or the calibration network 3 and the reflecting plate 2. The combination of the feeding of the probe 4 and the grounding of the metal screw 5 ensures the electrical performance and the structural reliability of the antenna, and also makes the structural design flexible and optimizes the size design of the calibration network 3. Meanwhile, the calibration network 3 and the antenna subarrays are grounded in the vicinity of the feed probe 4 through the metal screws 5 in a direct current manner, so that crosstalk between signals at radio frequency ports connected with the radio frequency connectors is effectively inhibited, S parameters of the radio frequency ports are improved, the amplitude, phase consistency and linearity of the calibration network 3 are ensured, and radio frequency signals are well transmitted in radio frequency channels formed by the radio frequency connectors, the calibration network 3, the probes 4 and the antenna subarrays.
Referring to fig. 5 to 9, which are graphs for testing performance experiments of 4.5G massive MIMO antennas, fig. 5 is a graph for testing amplitude deviation from a calibration port to each radio frequency port, and the inset graph is a maximum deviation result from the calibration port to each radiation port, it can be seen from the graph that the antenna of the present invention has good amplitude deviation values from the calibration port to each radiation port; fig. 6 is a graph of phase deviation test from the calibration port to each rf port, where the graph is the maximum deviation of the phase of the calibration port to each radiation port, and the test result shows that the antenna of the present invention has good phase deviation values from the calibration port to each radiation port; FIG. 7 is a graph of the isolation between the same polarization of each RF port, from which it can be seen that the antenna of the present invention has good isolation between the same polarization of each RF port; FIG. 8 is a chart of testing the isolation of different polarizations of each radio frequency port, from which it can be seen that the antenna of the present invention has good isolation of different polarizations of each radio frequency port; fig. 9 is a chart of standing wave at the rf port from which it can be seen that the antenna of the present invention has good standing wave at the rf port.
Of course, fig. 5 to 9 are only experimental graphs of performance tests of 4.5G massive MIMO antennas in an experiment of the present invention, and the present invention is also applicable to other frequency bands, such as 2.3G frequency band (2.3 GHz-2.5 GHz), 2.6G frequency band (2.496 GHz-2.690 GHz), 3.5G frequency band (3.4 GHz-3.8 GHz), and the like, and has good electrical performance.
The above-described embodiments are only one of the preferred embodiments of the present invention, and the ordinary changes and substitutions made by those skilled in the art within the scope of the present invention should be included in the scope of the present invention.