阅读说明：本技术 赋形波束定向天线 (Shaped beam directional antenna ) 是由 樊小景 张楷生 毛荟川 穆桐 于 2020-12-18 设计创作，主要内容包括：一种赋形波束定向天线,包括至少两个贴片天线排布在一个平面上组成的天线阵、多个单极子振子沿天线阵的外围设置组成的单极子阵列、金属桶状天线支撑结构体的外部以套装方式间隔设置至少两个三维金属扼流槽组成的扼流槽结构体,组成扼流槽结构体的各三维金属扼流槽的高度从内到外依次降低,且低于天线支撑结构体的高度,天线阵装在天线支撑结构体的顶部,罩壳覆罩着单极子阵列和天线阵以及扼流槽结构体并固定在扼流槽结构体最外层的三维金属扼流槽上。本发明用于卫星导航接收机进行卫星导航信号的双频段带收发定向,具有双圆极化、高低仰角增益、高相位中心精度的品质特性,结构紧凑,集成度高,便于装配和使用,能适应特殊场景的应用要求。(A shaped beam directional antenna comprises an antenna array formed by arranging at least two patch antennas on a plane, a plurality of monopole sub-arrays formed by arranging monopole sub-arrays along the periphery of the antenna array, a choke groove structure body formed by arranging at least two three-dimensional metal choke grooves at intervals in a sleeving manner outside a metal barrel-shaped antenna supporting structure body, wherein the height of each three-dimensional metal choke groove forming the choke groove structure body is sequentially reduced from inside to outside and is lower than the height of the antenna supporting structure body, the antenna array is arranged at the top of the antenna supporting structure body, and a housing covers the monopole sub-arrays, the antenna array and the choke groove structure body and is fixed on the three-dimensional metal choke groove at the outermost layer of the choke groove structure body. The dual-band directional antenna is used for the satellite navigation receiver to perform dual-band transceiving orientation of satellite navigation signals, has the quality characteristics of dual circular polarization, high and low elevation gain and high phase center precision, has a compact structure and high integration level, is convenient to assemble and use, and can meet the application requirements of special scenes.)

1. A shaped beam directional antenna for directional transceiving of satellite navigation signals by a satellite navigation receiver, comprising:

housing, patch antenna, monopole oscillator, antenna bearing structure body and three-dimensional metal choke groove, wherein:

at least two patch antennas are symmetrically arranged on a plane to form an antenna array, and feed points of the patch antennas are symmetrically distributed;

the plurality of monopole vibrators are arranged on the antenna array to form a monopole sub-array, and each monopole vibrator is arranged along the periphery of the antenna array;

the antenna supporting structure body is a metal barrel-shaped component;

at least two three-dimensional metal choke grooves are sleeved outside the antenna supporting structure body in a sleeving manner to form a choke groove structure body, the height of each three-dimensional metal choke groove forming the choke groove structure body is sequentially reduced from inside to outside, the height of the three-dimensional metal choke groove at the innermost layer in the choke groove structure body is lower than that of the antenna supporting structure body, and gaps are formed among the three-dimensional metal choke grooves and between the three-dimensional metal choke grooves and the antenna supporting structure body;

the antenna array is arranged on the top of the antenna supporting structure body, and the monopole array is positioned above the choke groove structure body;

the casing covers the monopole array, the antenna array, and the choke groove structure, and a bottom of the casing is fixed to a bottom of the three-dimensional metal choke groove constituting an outermost layer of the choke groove structure.

2. A shaped beam directional antenna as claimed in claim 1, wherein:

the antenna array is a double-element rectangular antenna array formed by arranging two patch antennas in parallel;

the monopole array is a rectangular array formed by at least 8 monopole elements distributed on the periphery of the double-element rectangular antenna array, and the same number of monopole elements are arranged around each patch antenna;

the antenna supporting structure body is a metal rectangular barrel-shaped component;

the three-dimensional metal choke groove is a rectangular structural part matched with the shape of the antenna supporting structure body, and the choke groove structure body is formed by three small-to-large three-dimensional metal choke grooves from inside to outside.

3. A shaped beam directional antenna as claimed in claim 1, wherein:

the patch antenna comprises a first radiation layer, a second radiation layer and a feed layer from top to bottom, the area of the second radiation layer is larger than that of the first radiation layer, the monopole element is installed on the plane of the first radiation layer, and the feed points are arranged on the first radiation layer and the second radiation layer;

the feed layer is provided with a first radiation layer feed network and a second radiation layer feed network, the first radiation layer feed network feeds a feed point of the first radiation layer through a probe of the first radiation layer, and the second radiation layer feed network feeds a feed point of the second radiation layer through a probe of the second radiation layer.

4. A shaped beam directional antenna as claimed in claim 3, wherein: the first radiation layer and the second radiation layer are both square.

5. A shaped beam directional antenna as claimed in claim 4, wherein: the square second radiation layer is cut at four right angles, and the size and the shape of the cut area are subject to the requirement that the second radiation layer can adapt to planar arrangement.

6. A shaped beam directional antenna as claimed in claim 3, wherein:

the first radiation layer and the second radiation layer are respectively provided with two feed points, the first radiation layer feed network respectively feeds the two feed points of the first radiation layer through two probes of the first radiation layer, and the second radiation layer feed network respectively feeds the two feed points of the second radiation layer through two probes of the second radiation layer.

7. A shaped beam directional antenna as claimed in claim 3, wherein:

the first radiation layer feed network and the second radiation layer feed network respectively comprise a group of two-stage power dividers, the first-stage power divider of the two-stage power dividers consists of one Wilkinson power divider, and the second-stage power divider of the two-stage power dividers consists of two Wilkinson power dividers;

the Wilkinson power dividers comprise combining ends and splitting ends, wherein the phase difference between the combining ends of the two Wilkinson power dividers forming the second-stage power divider is 180 degrees, and the phase difference between the splitting ends of the Wilkinson power dividers forming the second-stage power divider is 90 degrees.

8. A shaped beam directional antenna as claimed in claim 3, wherein:

and a metal isolation column is arranged around the probe of the first radiation layer and is positioned between the feed layer and the second radiation layer.

Technical Field

The invention relates to an antenna, in particular to a shaped beam directional antenna, and belongs to the technical field of radio antenna equipment production.

Background

The antenna is a component used for transmitting or receiving electromagnetic waves, is widely applied to engineering systems such as communication, broadcasting, television, radar, navigation, electronic countermeasure, remote sensing, radio astronomy and the like, and in the information age, all the information is transmitted by using the electromagnetic waves, and the antenna is required to work.

With the development of satellite navigation technology, the precision of radio positioning navigation is continuously improved, and correspondingly, higher requirements are put forward on the quality performance of a shaped beam directional antenna used as the front end of a satellite navigation receiver.

As a shaped beam directional antenna at the front end of a satellite navigation receiver, according to the working requirement, the antenna has more stable phase center precision and higher low elevation gain compared with a common antenna so as to adapt to a shaped beam of a special scene and meet the receiving and transmitting requirements of double frequency bands.

However, to satisfy these requirements of the directional antenna of the shaped beam as the front end of the satellite navigation receiver, the design of the antenna is difficult because:

firstly, the accuracy of the phase center of the shaped beam directional antenna is related to the structure and the feeding mode of the antenna, the more the feeding points are, the more symmetrical the feeding position is, the better the symmetry of the radiation structure is, and the more stable the phase center is, but the feeding network of the shaped beam directional antenna becomes quite complicated;

in order to suppress the multipath effect, the shaped beam directional antenna needs to have a relatively ideal hemispherical radiation directional pattern, which is expected to reduce the antenna back lobe and improve the low elevation gain and polarization purity of the antenna, but in the design of the conventional shaped beam directional antenna, the improvement of the low elevation gain and the antenna back lobe effect are difficult to be considered simultaneously;

in addition, the shaped beam directional antenna needs to perform dual-band transceiving operation, which requires to increase the isolation between the dual-band antennas, and the structure of the antenna becomes more complicated due to the integration of a radio transceiving component, namely, a TR component (acronym for transmitter and Receiver).

Therefore, how to design a shaped beam directional antenna capable of performing dual band transceiving, having dual circular polarization, high and low elevation gain, high phase center accuracy and quality performance, and compact structure has become a technical problem that those skilled in the art have made an effort to solve.

Disclosure of Invention

In order to solve the problem faced by the technicians in the field, the invention provides a shaped beam directional antenna, aiming at:

the shaped beam directional antenna can perform double-frequency band receiving and transmitting, has double circular polarization, high and low elevation gain, high phase center precision and compact structure, is suitable for the application requirement of shaped beams of special scenes, and meets the requirement of a satellite navigation receiver on directional receiving and transmitting of satellite navigation signals.

In order to achieve the purpose, the invention provides the following technical scheme:

a shaped beam directional antenna is used for a satellite navigation receiver to perform directional transceiving of satellite navigation signals, and comprises:

housing, patch antenna, monopole oscillator, antenna bearing structure body and three-dimensional metal choke groove, wherein:

at least two patch antennas are symmetrically arranged on a plane to form an antenna array;

the plurality of monopole vibrators are arranged on the antenna array to form a monopole sub-array, and each monopole vibrator is arranged along the periphery of the antenna array;

the antenna supporting structure body is a metal barrel-shaped component;

at least two three-dimensional metal choke grooves are sleeved outside the antenna supporting structure body in a sleeving manner to form a choke groove structure body, the height of each three-dimensional metal choke groove forming the choke groove structure body is sequentially reduced from inside to outside, the height of the three-dimensional metal choke groove at the innermost layer in the choke groove structure body is lower than that of the antenna supporting structure body, and gaps are formed among the three-dimensional metal choke grooves and between the three-dimensional metal choke grooves and the antenna supporting structure body;

the antenna array is arranged on the top of the antenna supporting structure body, and the monopole array is positioned above the choke groove structure body;

the casing covers the monopole array, the antenna array, and the choke groove structure, and a bottom of the casing is fixed to a bottom of the three-dimensional metal choke groove constituting an outermost layer of the choke groove structure.

Further:

the antenna array is a double-element rectangular antenna array formed by arranging two patch antennas in parallel;

the monopole array is a rectangular array formed by at least 8 monopole elements distributed on the periphery of the double-element rectangular antenna array, and the same number of monopole elements are arranged around each patch antenna;

the antenna supporting structure body is a metal rectangular barrel-shaped component;

the three-dimensional metal choke groove is a rectangular structural part matched with the shape of the antenna supporting structure body, and the choke groove structure body is formed by three small-to-large three-dimensional metal choke grooves from inside to outside.

Further:

the patch antenna comprises a first radiation layer, a second radiation layer and a feed layer from top to bottom, and the area of the second radiation layer is larger than that of the first radiation layer;

the monopole oscillator is arranged on the plane of the first radiation layer, and the feed point is arranged on the first radiation layer and the second radiation layer;

the feed layer is provided with a first radiation layer feed network and a second radiation layer feed network, the first radiation layer feed network feeds a feed point of the first radiation layer through a probe of the first radiation layer, and the second radiation layer feed network feeds a feed point of the second radiation layer through a probe of the second radiation layer.

Further, the first radiation layer and the second radiation layer are both square.

Furthermore, the square second radiation layer is cut at four right angles, and the size and the shape of the cut area are subject to the requirement that the second radiation layer can adapt to planar arrangement.

Further:

the first radiation layer and the second radiation layer are respectively provided with two feed points, the first radiation layer feed network respectively feeds the two feed points of the first radiation layer through two probes of the first radiation layer, and the second radiation layer feed network respectively feeds the two feed points of the second radiation layer through two probes of the second radiation layer.

Further:

the first radiation layer feed network and the second radiation layer feed network respectively comprise a group of two-stage power dividers, the first-stage power divider of the two-stage power dividers consists of one Wilkinson power divider, and the second-stage power divider of the two-stage power dividers consists of two Wilkinson power dividers;

the Wilkinson power dividers comprise combining ends and splitting ends, wherein the phase difference between the combining ends of the two Wilkinson power dividers forming the second-stage power divider is 180 degrees, and the phase difference between the splitting ends of the Wilkinson power dividers forming the second-stage power divider is 90 degrees.

Furthermore, a metal isolation column is arranged around a probe of the first radiation layer and is positioned between the feed layer and the second radiation layer.

Compared with the prior art, the invention has the beneficial effects and remarkable progresses that:

1) the invention provides a shaped beam directional antenna, comprising:

the antenna array is formed by arranging at least two patch antennas on a plane, a plurality of monopole elements are arranged along the periphery of the antenna array to form a monopole array, the exterior of a metal barrel-shaped antenna supporting structure body is sleeved with a choke groove structure body formed by at least two three-dimensional metal choke grooves at intervals in a sleeving manner, the height of each three-dimensional metal choke groove forming the choke groove structure body is reduced from inside to outside in sequence and is lower than that of the antenna supporting structure body, the antenna array is arranged at the top of the antenna supporting structure body, and a casing covers the monopole array, the antenna array and the choke groove structure body and is fixed at the bottom of the three-dimensional metal choke groove forming the outermost layer of the choke groove structure body, so that a shaped beam directional antenna for a satellite navigation receiver to directionally receive and send satellite navigation signals is;

2) the invention provides a shaped beam directional antenna, which comprises the following components:

the patch antennas with radiation layers of different sizes which are arranged in a laminated manner are arranged, so that the shaped beam directional antenna provided by the invention can work in dual frequency bands;

a metal isolation column is arranged at a position close to the low-frequency feed point to connect the metal ground and the second radiation patch, so that the isolation between the double-frequency antennas is improved;

the monopole subarray is arranged along the periphery of the antenna array, so that a radiation field of the antenna array generates scattering on the monopole subarray, and the low elevation gain of the shaped beam directional antenna provided by the invention is improved;

the antenna array is arranged on the antenna supporting structure body sleeved with the choke groove structure body, so that the backward radiation performance of the antenna array is reduced, and the inhibiting capability of the shaped beam directional antenna on the multipath effect is improved;

3) the formed beam directional antenna provided by the invention has the advantages that through the integral symmetrical design, the formed beam directional antenna comprises the symmetrical arrangement of patch antennas in an antenna array, the symmetrical arrangement of feed points of the patch antennas, a choke groove structure body formed by three-dimensional metal choke grooves with symmetrical structures and the like, so that the formed beam directional antenna provided by the invention can have excellent phase center precision;

4) the shaped beam directional antenna provided by the invention has the advantages of compact integral structure, high integration level and convenience in assembly and use, and larger space is reserved in the antenna support structure body, so that the TR component is convenient to mount, the application is favorably expanded, the application requirement of a shaped beam in a special scene can be met, and the shaped beam directional antenna has great popularization and application values.

Drawings

To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments of the present invention will be briefly described below.

Obviously:

the drawings in the following description are only part of the embodiments of the present invention, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without creative efforts, but the other drawings also belong to the drawings required to be used by the embodiments of the present invention.

Fig. 1 is a schematic perspective exploded view of a shaped beam directional antenna according to the present invention;

fig. 2 is a schematic front view of a shaped beam directional antenna provided by the present invention with a cover removed;

fig. 3 is a schematic top view of a first radiation layer and a second radiation layer of each patch antenna forming an antenna array in a shaped beam directional antenna according to the present invention;

fig. 4 is a schematic wiring diagram of the feed layers of the patch antennas forming the antenna array in the shaped beam directional antenna provided by the present invention.

In the figure:

10-a housing, 20-a patch antenna, 30-a monopole element, 40-an antenna support structure and 50-a three-dimensional metal choke groove;

21-a first radiation layer, 22-a second radiation layer, 23-a feed layer, and 24-a metal isolation column;

231-first radiation layer feed network, 232-second radiation layer feed network.

Detailed Description

In order to make the objects, technical solutions, advantages and significant progress of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings provided in the present specification, and it is obvious that all of the described embodiments are only some embodiments of the present invention, not all embodiments;

all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that:

the terms "first," "second," and the like in the description and claims of the present invention and in the drawings of embodiments of the present invention, are used for distinguishing between different objects and not for describing a particular order;

furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to the listed steps or elements, but may alternatively include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

It is to be understood that:

in the description of the embodiments of the present invention, the terms indicating orientation or position are used only for convenience of describing the embodiments of the present invention and for simplicity of explanation, and do not indicate or imply that the described devices or elements must have a specific orientation, a specific orientation configuration and operation, and therefore, the present invention should not be construed as limited.

In the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as a fixed connection, a removable connection, a movable connection, or an integral part; the term "a" or "an" refers to a compound that can be directly connected or indirectly connected through an intermediate, or can be connected to each other or interact with each other, and unless otherwise specifically limited, the specific meaning of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

It should also be noted that:

the following embodiments may be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

The technical means of the present invention will be described in detail below with specific examples.

Examples

As shown in fig. 1, a schematic three-dimensional exploded structure of a shaped beam directional antenna provided by the present invention, and fig. 2, a schematic front view structure of the shaped beam directional antenna provided by the present invention without a housing is shown:

a shaped beam directional antenna is used for a satellite navigation receiver to perform directional transceiving of satellite navigation signals, and comprises:

housing 10, patch antenna 20, monopole element 30, antenna support structure 40, and three-dimensional metal choke groove 50, wherein:

at least two patch antennas 20 are symmetrically arranged on a plane to form an antenna array;

a plurality of monopole vibrators 30 are arranged on the antenna array to form a monopole sub-array, and each monopole vibrator 30 is arranged along the periphery of the antenna array;

the antenna support structure 40 is a metal barrel;

at least two three-dimensional metal choke grooves 50 are sleeved outside the antenna support structure 40 in a sleeved manner to form a choke groove structure, the height of each three-dimensional metal choke groove 50 forming the choke groove structure is reduced from inside to outside in sequence, the height of the three-dimensional metal choke groove 50 at the innermost layer in the choke groove structure is lower than that of the antenna support structure 40, and gaps are formed among the three-dimensional metal choke grooves 50 and between the three-dimensional metal choke grooves 50 and the antenna support structure 40;

the antenna array is arranged on the top of the antenna supporting structure body 40, and the monopole array is positioned above the choke groove structure body;

the housing 10 covers the monopole array and the antenna array and the choke groove structure, and the bottom of the housing 10 is fixed to the bottom of a three-dimensional metal choke groove 50 constituting the outermost layer of the choke groove structure.

Further, as an alternative implementation, as can be seen from fig. 1 and fig. 2, in this embodiment:

the antenna array is a double-element rectangular antenna array formed by arranging two patch antennas 20 in parallel;

the monopole array is a rectangular array formed by arranging at least 8 monopole oscillators 30 on the periphery of the double-element rectangular antenna array, and the same number of monopole oscillators 30 are arranged around each patch antenna 20;

the antenna support structure 40 is a metal rectangular barrel-shaped member;

the three-dimensional metal choke groove 50 is a rectangular structural member matching the shape of the antenna support structure 40, and the choke groove structure is composed of three small-to-large three-dimensional metal choke grooves 50 from the inside to the outside.

Further, as shown in fig. 3, a schematic top view structure diagram of a shaped beam directional antenna when a first radiation layer and a second radiation layer of each patch antenna forming an antenna array are combined together, and fig. 4, a schematic wiring diagram of a feed layer of each patch antenna forming an antenna array in a shaped beam directional antenna provided by the present invention, in this embodiment:

the patch antenna 20 includes a first radiation layer 21, a second radiation layer 22 and a feed layer 23 from top to bottom, and the area of the second radiation layer 22 is larger than that of the first radiation layer 21;

the monopole oscillator 30 is arranged on the plane of the first radiation layer 21, and the feed points are arranged on the first radiation layer 21 and the second radiation layer 22;

the feed layer 23 is provided with a first radiation layer feed network 231 and a second radiation layer feed network 232, the first radiation layer feed network 231 feeds the feed point of the first radiation layer 21 through the probe thereof, and the second radiation layer feed network 232 feeds the feed point of the second radiation layer 22 through the probe thereof.

Further, as an optional implementation manner, as can be seen from fig. 3, in this embodiment:

the first radiation layer 21 and the second radiation layer 22 are both square and

the square second radiation layer 22 has four right angles cut out, the size and shape of the cut-out area of the second radiation layer 22 are determined by the requirement that the second radiation layer 22 can be arranged in a plane, and in this embodiment, the square second radiation layer 22 has four right angles cut out of a triangular area.

Further, in this embodiment:

the first radiation layer 21 and the second radiation layer 22 each have two feeding points, the first radiation layer feeding network 231 feeds the two feeding points of the first radiation layer 21 through two probes thereof, and the second radiation layer feeding network 232 feeds the two feeding points of the second radiation layer 22 through two probes thereof.

Further, as can be seen from fig. 4, as an optional technical solution, in this embodiment:

the first radiation layer feed network 231 and the second radiation layer feed network 232 respectively comprise a group of two-stage power dividers, the first-stage power divider of the two-stage power dividers comprises a Wilkinson power divider, the second-stage power divider of the two-stage power dividers comprises two Wilkinson power dividers, each Wilkinson power divider comprises a combining end and a splitting end, the phase difference between the combining ends of the two Wilkinson power dividers forming the second-stage power divider is 180 degrees, and the phase difference between the splitting ends of the Wilkinson power dividers forming the second-stage power divider is 90 degrees.

Further, as can be seen from fig. 3, as an optional technical solution, in this embodiment:

a metal isolation column 24 is further disposed between the periphery of the probe of the first radiation layer 21 and the feed layer 23, and the metal isolation column 24 is located between the feed layer 23 and the second radiation layer 22.

From the above description, it can be seen that:

first, the shaped beam directional antenna provided in this embodiment includes:

the antenna array is formed by arranging at least two patch antennas on a plane, a plurality of monopole elements are arranged along the periphery of the antenna array to form a monopole array, the exterior of a metal barrel-shaped antenna supporting structure body is sleeved with a choke groove structure body formed by at least two three-dimensional metal choke grooves at intervals in a sleeving manner, the height of each three-dimensional metal choke groove forming the choke groove structure body is reduced from inside to outside in sequence and is lower than that of the antenna supporting structure body, the antenna array is arranged at the top of the antenna supporting structure body, and a casing covers the monopole array, the antenna array and the choke groove structure body and is fixed at the bottom of the three-dimensional metal choke groove forming the outermost layer of the choke groove structure body, so that a shaped beam directional antenna for a satellite navigation receiver to directionally receive and send satellite navigation signals is;

secondly, the shaped beam directional antenna provided by the invention comprises the following components:

the patch antennas with radiation layers of different sizes which are arranged in a laminated manner are arranged, so that the shaped beam directional antenna provided by the invention can work in dual frequency bands;

a metal isolation column is arranged at a position close to the low-frequency feed point to connect the metal ground and the second radiation patch, so that the isolation between the double-frequency antennas is improved;

the monopole subarray is arranged along the periphery of the antenna array, so that a radiation field of the antenna array generates scattering on the monopole subarray, and the low elevation gain of the shaped beam directional antenna provided by the invention is improved;

the antenna array is arranged on the antenna supporting structure body sleeved with the choke groove structure body, so that the backward radiation performance of the antenna array is reduced, and the inhibiting capability of the shaped beam directional antenna on the multipath effect is improved;

thirdly, the shaped beam directional antenna provided by the embodiment of the invention has excellent phase center accuracy by the overall symmetrical design, including the symmetrical arrangement of patch antennas in the antenna array, the symmetrical arrangement of feed points of the patch antennas, and the formation of a choke groove structure body by adopting a three-dimensional metal choke groove with a symmetrical structure;

in summary, it can be seen that:

the shaped beam directional antenna provided by the invention can perform dual-band transceiving, has the quality characteristics of dual circular polarization, high and low elevation gain and high phase center precision, has a compact integral structure and high integration level, is convenient to assemble and use, reserves a larger space in an antenna supporting structure body to facilitate the installation of a TR component, is favorable for further expanding application, can adapt to the application requirement of a shaped beam in a special scene, meets the requirement of a satellite navigation receiver on directional transceiving of satellite navigation signals, and has great popularization and application values.

It should be noted that:

in the description above, the terms "present embodiment," "present invention embodiment," "as shown at … …," "further," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention, and it is not necessary for the term to be construed as a descriptive limitation in this description for the same embodiment or example, and that the particular feature, structure, material, or characteristic described may be combined or coupled in any suitable manner in any one or more embodiments or examples.

Furthermore, those of ordinary skill in the art may combine or combine features of different embodiments or examples and features of different embodiments or examples described in this specification without undue conflict.

Finally, it should be noted that:

although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made on the technical solutions described in the foregoing embodiments, or some or all of the technical features of the embodiments can be equivalently replaced, and the corresponding technical solutions do not depart from the technical solutions of the embodiments of the present invention.