Patent Publication Number: US-2023163478-A1

Title: Antenna and manufacturing method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a National Phase Application filed under 35 U.S.C. 371 as a national stage of PCT/CN2021/080751 filed on Mar. 15, 2021, the content of which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure belongs to the field of communication technology, and specifically relates to an antenna and a manufacturing method thereof. 
     BACKGROUND 
     Compared with the 4th generation mobile communication technology (4G), the 5th generation mobile communication technology (5G) has the advantages of higher data rate, larger network capacity, less time delay, and the like. The 5G frequency plan includes two parts, namely a low-frequency band and a high-frequency band. The low-frequency band (3-6 GHz) has good propagation characteristics and very abundant spectrum resources. Therefore, the development of antenna units and arrays for communication applications using the low-frequency band has gradually become a hotspot in the research and development at the current stage. 
     Based on the practical application scenarios of 5G mobile communications, a 5G low-frequency band antenna (i.e., a 5G antenna using the low-frequency band) should have technical features such as high gain, miniaturization, and broad band. A microstrip antenna is a commonly used antenna form which has a simple structure, is easy to array and can realize a relatively high gain. However, application of the microstrip antenna in 5G low-frequency mobile communication is limited by the narrow bandwidth of the microstrip antenna and the large antenna size of the microstrip antenna at the low-frequency band. 
     SUMMARY 
     Embodiments of the present disclosure provide an antenna and a manufacturing method thereof. 
     In a first aspect, an embodiment of the present disclosure provides an antenna, including: 
     a dielectric layer with a first surface and a second surface disposed opposite to each other; 
     a reference electrode layer disposed on the first surface of the dielectric layer and provided with at least one slot therein; 
     at least one radiation structure disposed on the second surface of the dielectric layer, with an orthogonal projection of one radiation structure on the dielectric layer located in an orthogonal projection of one slot on the dielectric layer; wherein each radiation structure includes a plurality of radiation parts spaced apart from each other, each of which includes radiation elements spaced apart from each other; and the plurality of radiation parts in each radiation structure include at least a first radiation part and a second radiation part; and 
     at least one first microstrip line and at least one second microstrip line disposed on the second surface of the dielectric layer; wherein one first microstrip line is configured to feed power to the radiation elements in one first radiation part, one second microstrip line is configured to feed power to the radiation elements in one second radiation part, and the first microstrip line has a feed direction different from that of the second microstrip line. 
     The feed direction of one of the first microstrip line and the second microstrip line is a vertical direction and the feed direction of the other of the first microstrip line and the second microstrip line is a horizontal direction. 
     The first radiation part and the second radiation part each include two radiation elements spaced apart from each other; the first microstrip line and the second microstrip line each include one connection part and two branch parts connected with the connection part; the two branch parts of the first microstrip line are respectively connected to the two radiation elements in the first radiation part; and the two branch parts of the second microstrip line are respectively connected to the two radiation elements in the second radiation part. 
     Orthogonal projections of the first microstrip line and the second microstrip line on the dielectric layer each at least partially overlap an orthogonal projection of the slot on the dielectric layer; and orthogonal projections of the two branch parts of the first microstrip line and the two branch parts of the second microstrip line on the dielectric layer are each located in the orthogonal projection of the slot on the dielectric layer. 
     The plurality of radiation parts in the radiation structure further include: a third radiation part and a fourth radiation part; wherein the third radiation part is disposed opposite to the first radiation part, and the fourth radiation part is disposed opposite to the second radiation part. 
     Each radiation element has a triangular plate-shaped structure, the first, second, third and fourth radiation parts each include two radiation elements spaced apart from each other, and the radiation elements in the radiation structure form a double-cross shaped opening. 
     The radiation structure has a rectangular contour, and the slot is rectangular. 
     In each radiation structure, a distance between the radiation parts is greater than a distance between the radiation elements. 
     The antenna further includes a first feed structure and a second feed structure, wherein the first feed structure and the second feed structure are each located on the second surface of the dielectric layer, an orthogonal projection of the first feed structure on the dielectric layer overlaps at least partially an orthogonal projection of the first microstrip line on the dielectric layer, and an orthogonal projection of the second feed structure on the dielectric layer overlaps at least partially an orthogonal projection of the second microstrip line on the dielectric layer. 
     The first feed structure is electrically connected to the first microstrip line; and the second feed structure is electrically connected to the second microstrip line. 
     The number of the at least one slot is 2 n , the first feed structure includes n levels of third microstrip lines, and the second feed structure includes n levels of fourth microstrip lines; 
     one 1st level third microstrip line is connected to two adjacent first microstrip lines, and different 1st level third microstrip lines are respectively connected to different first microstrip lines; and one m th  level third microstrip line is connected to two adjacent (m−1) th  level third microstrip lines, and different m th  level third microstrip lines are respectively connected to different (m−1) th  level third microstrip lines; and 
     one 1st level fourth microstrip line is connected to two adjacent second microstrip lines, and different 1st level fourth microstrip lines are respectively connected to different second microstrip lines; and one m th  level fourth microstrip line is connected to two adjacent (m−1) th  level fourth microstrip lines, and different m th  level fourth microstrip lines are respectively connected to different (m−1) th  level fourth microstrip lines; where n≥2, 2≤m≤n, and m and n are both integers. 
     The reference electrode layer includes a body part, a first branch and a second branch; the first branch and the second branch are respectively connected to two sides of the body part in a lengthwise direction of the body part; the antenna further includes a fifth microstrip line and a sixth microstrip line; the fifth microstrip line is connected to the first feed structure, and an orthogonal projection of the fifth microstrip line on the dielectric layer is located in an orthogonal projection of the first branch on the dielectric layer; the sixth microstrip line is connected to the second feed structure, and an orthogonal projection of the sixth microstrip line on the dielectric layer is located in an orthogonal projection of the second branch on the dielectric layer; and 
     a perpendicular bisector of a width of the body part coincides with one diagonal line of the dielectric layer; and an extending direction of the fifth microstrip line is perpendicular to an extending direction of the sixth microstrip line, and an angle between the extending direction of each of the fifth and sixth microstrip lines and the diagonal line of the dielectric layer is 45°. 
     The antenna includes feed regions and a radiation region; the first feed structure and the second feed structure are respectively located in the feed region; the radiation structure is located in the radiation region; the reference electrode layer further includes at least one auxiliary slot located in each of the feed regions; and an orthogonal projection of the auxiliary slot on the dielectric layer does not overlap orthogonal projections of the first feed structure and the second feed structure on the dielectric layer. 
     The dielectric layer includes a first sub-dielectric layer, a first bonding layer, a second sub-dielectric layer, a second bonding layer, and a third sub-dielectric layer disposed in a stack, wherein a surface of the first sub-dielectric layer distal to the first bonding layer serves as the first surface of the dielectric layer, and a surface of the third sub-dielectric layer distal to the second bonding layer serves as the second surface of the dielectric layer. 
     The dielectric layer includes a first sub-dielectric layer, a first bonding layer, a second sub-dielectric layer, a second bonding layer, and a third sub-dielectric layer disposed in a stack, wherein a surface of the first sub-dielectric layer proximal to the first bonding layer serves as the first surface of the dielectric layer, and a surface of the third sub-dielectric layer proximal to the second bonding layer serves as the second surface of the dielectric layer. 
     The first sub-dielectric layer and the third sub-dielectric layer each include polyimide; and the second sub-dielectric layer includes polyethylene glycol terephthalate. 
     The dielectric layer includes a first sub-dielectric layer, a first bonding layer and a second sub-dielectric layer disposed in a stack, wherein a surface of the first sub-dielectric layer distal to the first bonding layer serves as the first surface of the dielectric layer, and a surface of the second sub-dielectric layer distal to the first bonding layer serves as the second surface of the dielectric layer; and
         the first sub-dielectric layer includes a material of polyimide, and the second sub-dielectric layer includes a material of polyethylene glycol terephthalate, or   the first sub-dielectric layer includes a material of polyethylene glycol terephthalate, and the second sub-dielectric layer includes a material of polyimide.       

     The dielectric layer has a single-layer structure and includes a material of polyimide or polyethylene glycol terephthalate. 
     The at least one slot includes a plurality of slots arranged side by side, with a constant distance between adjacent slots. 
     In a second aspect, an embodiment of the present disclosure provides a method for manufacturing an antenna, including: 
     providing a dielectric layer; 
     forming a pattern including a reference electrode layer on a first surface of the dielectric layer through a patterning process; wherein a slot is formed in the reference electrode layer; and 
     forming a pattern including at least one radiation structure, at least one first microstrip line and at least one second microstrip line on a second surface of the dielectric layer through a patterning process; wherein an orthogonal projection of one radiation structure on the dielectric layer is located in an orthogonal projection of the slot on the dielectric layer; the radiation structure includes a plurality of radiation parts spaced apart from each other, each of which includes radiation elements spaced apart from each other; and the plurality of radiation parts in each radiation structure include at least a first radiation part and a second radiation part; one first microstrip line is configured to feed power to the radiation elements in one first radiation part, one second microstrip line is configured to feed power to the radiation elements in one second radiation part, and the first microstrip line has a feed direction different from that of the second microstrip line. 
     The dielectric layer includes a first sub-dielectric layer, a first bonding layer, a second sub-dielectric layer, a second bonding layer, and a third sub-dielectric layer sequentially disposed in a stack, wherein 
     the reference electrode layer is formed on a side of the first sub-dielectric layer distal to the first bonding layer; and the radiation structure is formed on a side of the third sub-dielectric layer distal to the second bonding layer. 
     The dielectric layer includes a first sub-dielectric layer, a first bonding layer, a second sub-dielectric layer, a second bonding layer, and a third sub-dielectric layer sequentially disposed in a stack, wherein 
     the reference electrode layer is formed on a side of the first sub-dielectric layer proximal to the first bonding layer; and the radiation structure is formed on a side of the third sub-dielectric layer proximal to the second bonding layer. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a cross-sectional view of an antenna according to an embodiment of the present disclosure. 
         FIG.  2    is a top view of an antenna according to an embodiment of the present disclosure. 
         FIG.  3    is a cross-sectional view of another antenna according to an embodiment of the present disclosure. 
         FIG.  4    is a cross-sectional view of another antenna according to an embodiment of the present disclosure. 
         FIG.  5    is a cross-sectional view of another antenna according to an embodiment of the present disclosure. 
         FIG.  6    is a S11 parameter graph (including two S11 parameter curves) of a feed end of a first microstrip line and a feed end of a second microstrip line of the antenna unit shown in  FIG.  2   . 
         FIG.  7   a    is a planar radiation pattern obtained by exciting the feed end of the first microstrip line of the antenna unit shown in  FIG.  2    when f=3.75 GHz. 
         FIG.  7   b    is a planar radiation pattern obtained by exciting the feed end of the second microstrip line of the antenna unit shown in  FIG.  2    when f=3.75 GHz. 
         FIG.  8    is a top view of another antenna according to an embodiment of the present disclosure. 
         FIG.  9    is a S11 parameter graph (including two S11 parameter curves) of the feed end of the first feed structure and the feed end of the second feed structure of the antenna shown in  FIG.  8   . 
         FIG.  10   a    is a planar radiation pattern obtained by exciting the feed end of the first feed structure of the antenna shown in  FIG.  8    when f=3.75 GHz. 
         FIG.  10   b    is a planar radiation pattern obtained by exciting the feed end of the second feed structure of the antenna shown in  FIG.  8    when f=3.75 GHz. 
         FIG.  11    is a top view of another antenna according to an embodiment of the present disclosure. 
         FIG.  12    is a S11 parameter graph (including two S11 parameter curves) of a feed end of a fifth microstrip line and a feed end of a sixth microstrip line of the antenna unit shown in  FIG.  11   . 
         FIG.  13   a    is a planar radiation pattern obtained by exciting the feed end of the fifth microstrip line of the antenna shown in  FIG.  11    when f=3.75 GHz. 
         FIG.  13   b    is a planar radiation pattern obtained by exciting the feed end of the sixth microstrip line of the antenna shown in  FIG.  11    when f=3.75 GHz. 
         FIG.  14    is a top view of another antenna according to an embodiment of the present disclosure. 
     
    
    
     DETAIL DESCRIPTION OF EMBODIMENTS 
     To improve understanding of the technical solution of the present disclosure for one of ordinary skill in the art, the present disclosure will now be described in detail with reference to accompanying drawings and specific embodiments. 
     Unless otherwise defined, technical or scientific terms used in the present disclosure are intended to have general meanings as understood by one of ordinary skill in the art. The words “first”, “second” and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are used merely for distinguishing different components. Also, the use of the terms “a”, “an”, “the” of a similar referent does not denote a limitation of quantity, but rather denotes the presence of at least one. The word “comprising”, “including” or the like means that the element or item preceding the word contains elements or items that appear after the word or equivalents thereof, but does not exclude other elements or items. The term “connected”, “coupled” or the like is not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect connections. The words “upper”, “lower”, “left”, “right”, and the like are merely used to indicate a relative positional relationship, and when an absolute position of the described object is changed, the relative positional relationship may also be changed accordingly. 
     It should be noted that S11 mentioned herein refers to one of the S parameters that represents return loss characteristics (i.e., represents a return loss), and the dB value and impedance characteristics of the loss thereof are generally tested by a network analyzer. The parameter S11 represents a performance of the emission efficiency of an antenna, and the larger the value is, the more energy is reflected from the antenna itself, and the worse the efficiency of the antenna is. 
     In a first aspect, an embodiment of the present disclosure provides an antenna.  FIG.  1    is a cross-sectional view of an antenna according to an embodiment of the present disclosure; and  FIG.  2    is a top view of an antenna according to an embodiment of the present disclosure. As shown in  FIGS.  1  and  2   , the antenna includes a dielectric layer  1 , a reference electrode layer  2 , at least one radiation structure  3 , at least one first microstrip line  4  and at least one second microstrip line  5 . 
     The dielectric layer  1  has a first surface (lower surface) and a second surface (upper surface) disposed oppositely. 
     The reference electrode layer  2  is disposed on the first surface of the dielectric layer  1  and provided with at least one slot  21  therein. The at least one radiation structure  3  is disposed on the second surface of the dielectric layer  1 , with an orthogonal projection of one radiation structure  3  on the dielectric layer  1  located in an orthogonal projection of one slot  21  of the reference electrode layer  2  on the dielectric layer  1 . For example: when a plurality of radiation structures  3  are provided, a plurality of slots  21  are provided on the corresponding reference electrode layer  2 , and the plurality of radiation structures  3  are disposed to be in one-to-one correspondence with the plurality of slots  21 . It should be noted here that in the embodiment of the present disclosure, the reference electrode layer  2  may be a ground electrode layer, which means that a ground potential is written into the reference electrode layer  2 . 
     The radiation structure  3  includes a plurality of radiation parts spaced apart from each other, each of which includes radiation elements  301  spaced apart from each other. For example: the radiation parts in each radiation structure  3  include at least a first radiation part  31  and a second radiation part  32 ; and in this case, the first radiation part  31  and the second radiation part  32  each include radiation elements  301  spaced apart from each other. It should be noted that, in the embodiment of the present disclosure, the description is made by taking the case where two radiation elements  301  spaced apart from each other are included in each radiation part as an example, but it will be appreciated that the number of radiation parts in each radiation part is not limited to two, and may be specifically set according to the performance requirement of the antenna. 
     The at least one first microstrip line  4  and the at least one second microstrip line  5  are each disposed on the second surface of the dielectric layer  1 . One first microstrip line  4  is configured to feed power to the two radiation elements  301  in one first radiation part  31 , one second microstrip line  5  is configured to feed power to the two radiation elements  301  in one second radiation part  32 , and the first microstrip line  4  has a feed direction different from that of the second microstrip line  5 . 
     For example: when a plurality of radiation structures  3  are provided, correspondingly, a plurality of first radiation parts  31  and a plurality of second radiation parts  32  are provided. In this case, first microstrip lines  4  may be disposed in one-to-one correspondence with the first radiation parts  31 , and second microstrip lines  5  may be disposed in one-to-one correspondence with the second radiation parts  32 . In some examples, one of each first microstrip line  4  and each second microstrip line  5  has a feed direction being a vertical direction Y, and the other has a feed direction being a horizontal direction X. It should be noted that the feed direction of each first microstrip line  4  is a direction in which an input of a first microwave signal is excited and fed into the first radiation part  31 ; and the feed direction of each second microstrip line is a direction in which an input of a second microwave signal is excited and fed into the second radiation part  32 ; and the horizontal direction X and the vertical direction Y are relative concepts, which means that when the feed direction of each first microstrip line  4  is the vertical direction Y, the feed direction of each second microstrip line  5  is the horizontal direction X, and vice versa. In an embodiment of the present disclosure the illustration is made by taking the example where the first microstrip line  4  is connected to a right side of the radiation structure  3 , and has the feed direction being the vertical direction Y, and the second microstrip line  5  is connected to a lower side of the radiation structure  3 , and has the feed direction being the horizontal direction X. 
     In the antenna provided in the embodiment of the present disclosure, the first radiation part  31  and the second radiation part  32  of the radiation structure  3  each include two radiation elements  301  spaced apart from each other. The two radiation elements  301  in the first radiation part  31  are connected to one first microstrip line  4 , and the two radiation elements  301  in the second radiation part  32  are connected to one second microstrip line  5 . That is, each radiation part, which is divided into two elements, is fed by one feed line, thereby expanding the bandwidth thereof and improving the gain of the antenna. Meanwhile, the feed direction of the first microstrip line  4  is the vertical direction Y, which realizes horizontal polarization of the antenna, and the feed direction of the second microstrip line  5  is the horizontal direction X, which realizes vertical polarization of the antenna. In other words, the antenna in the embodiment of the present disclosure is a dual-polarization antenna. 
     In some examples, as shown in  FIG.  1   , the dielectric layer  1  in the antenna includes, but is not limited to, a flexible material, such as: polyimide (PI) or polyethylene glycol terephthalate (which may also be referred to as polyethylene terephthalate, PET). Alternatively, the dielectric layer  1  may be made of a glass-based material. In some examples, when the dielectric layer  1  is made of PET, it has a thickness of 250 μm and a dielectric constant of 3.34. 
     In some examples,  FIG.  3    is a cross-sectional view of another antenna according to an embodiment of the present disclosure. As shown in  FIG.  3   , the dielectric layer  1  in the antenna is a composite film layer, including a first sub-dielectric layer  11 , a first bonding layer  12 , a second sub-dielectric layer  13 , a second bonding layer  14 , and a third sub-dielectric layer  15 , which are sequentially stacked on top of each other. The reference electrode layer  2  is disposed on a side of the first sub-dielectric layer  11  distal to the first bonding layer  12 , which means that a side surface of the first sub-dielectric layer  11  distal to the first bonding layer  12  serves as the first surface of the dielectric layer  1 . The radiation elements  301  are disposed on a side of the third sub-dielectric layer  15  distal to the second bonding layer  14 , which means that a side surface of the third sub-dielectric layer  15  distal to the second bonding layer  14  serves as the second surface of the dielectric layer  1 . In some examples, the first sub-dielectric layer  11  and the third sub-dielectric layer  15  include, but are not limited to, PI materials; and the second sub-dielectric layer  13  includes, but is not limited to, a polyethylene glycol terephthalate (PET) material. The first bonding layer  12  and the second bonding layer  14  may be made of an optical clear adhesive (OCA). 
     In some examples,  FIG.  4    is a cross-sectional view of another antenna according to an embodiment of the present disclosure. As shown in  FIG.  4   , the dielectric layer  1  in this antenna has the same structure as the dielectric layer  1  in the antenna shown in  FIG.  3   , and includes a first sub-dielectric layer  11 , a first bonding layer  12 , a second sub-dielectric layer  13 , a second bonding layer  14 , and a third sub-dielectric layer  15 , which are sequentially stacked on top of each other. The reference electrode layer  2  is disposed on a side of the first sub-dielectric layer  11  proximal to the first bonding layer  12 , which means that a side surface of the first sub-dielectric layer  11  proximal to the first bonding layer  12  serves as the first surface of the dielectric layer  1 . The radiation structure  3  is disposed on a side of the third sub-dielectric layer  15  proximal to the second bonding layer  14 , which means that a side surface of the third sub-dielectric layer  15  proximal to the second bonding layer  14  serves as the second surface of the dielectric layer  1 . In some examples, the first sub-dielectric layer  11  and the third sub-dielectric layer  15  include, but are not limited to, PI materials; and the second sub-dielectric layer  13  includes, but is not limited to, a polyethylene glycol terephthalate (PET) material. The first bonding layer  12  and the second bonding layer  14  may be made of an optical clear adhesive (OCA). 
     In some examples,  FIG.  5    is a cross-sectional view of another antenna according to an embodiment of the present disclosure. As shown in  FIG.  5   , the dielectric layer  1  in this antenna includes a first sub-dielectric layer  11 , a first bonding layer  12 , and a second sub-dielectric layer  13  that are disposed in a stack. A surface of the first sub-dielectric layer  11  distal to the first bonding layer  12  serves as the first surface of the dielectric layer  1 . That is, the reference electrode layer  2  is disposed on a side of the first sub-dielectric layer distal to the first bonding layer  12 . A surface of the second sub-dielectric layer  13  distal to the first bonding layer  12  serves as the second surface of the dielectric layer  1 . That is, the radiation structure is disposed on a side of the second sub-dielectric layer  13  distal to the first bonding layer  12 . The first sub-dielectric layer  11  is made of a material including polyimide, and the second sub-dielectric layer  13  is made of a material including polyethylene glycol terephthalate. Alternatively, the first sub-dielectric layer  11  is made of a material including polyethylene glycol terephthalate, and the second sub-dielectric layer  13  is made of a material including polyimide. 
     In some examples, with continued reference to  FIG.  1    and  FIG.  2   , the first radiation part  31  and the second radiation part  32  of the radiation structure  3  each include two radiation elements  301  spaced apart from each other. In this case, the first microstrip line  4  and the second microstrip line  5  each include one connection part and two branch parts. In other words, the first microstrip line  4  and the second microstrip line  5  each adopt a one-to-two structure. In this case, the two branch parts of the first microstrip line  4  are respectively connected to the two radiation elements  301  in the first radiation part  31 . That is, the branch parts of the first microstrip line  4  are connected to the radiation elements  301  in the first radiation part  31  in one-to-one correspondence. Similarly, the two branch parts of the second microstrip line  5  are respectively connected to the two radiation elements  301  in the second radiation part  32 . That is, the two branch parts of the second microstrip line  5  are connected to the two radiation elements in the second radiation part  32  in one-to-one correspondence. 
     With continued reference to  FIG.  1    and  FIG.  2   , orthogonal projections of the first microstrip line  4  and the second microstrip line  5  on the dielectric layer  1  each at least partially overlap an orthogonal projection of the slot in the reference electrode layer  2  on the dielectric layer  1 , and orthogonal projections of the branch parts of the first microstrip line  4  and the second microstrip line on the dielectric layer  1  are each located in the orthogonal projection of the slot in the reference electrode layer  2  on the dielectric layer  1 . With such arrangement, a radiation direction of a microwave signal can be adjusted. 
     In some examples, as shown in  FIG.  2   , one slot  21  in the reference electrode layer  2 , one radiation structure  3 , one first microstrip line  4 , and one second microstrip line  5  correspondingly disposed in the antenna form one antenna unit  10 . In some examples, a ratio of a length to a width of the antenna unit  10  is about 1:1, such as 1:0.8 to 1:1.25; and a ratio of the length to a thickness is about 100:1 to 200:1. The slot  21  has a shape the same or substantially the same as a contour shape of the radiation structure  3 . For example: the slot  21  has a rectangular shape, and the radiation structure  3  also has a rectangular contour shape.  FIG.  2    takes the slot  21  and the radiation structure  3  both being rectangular as an example. In this case, each radiation structure  3  includes four radiation parts. That is, the radiation structure  3  includes not only the first radiation part  31  and the second radiation part  32 , but also a third radiation part  33  and a fourth radiation part  34 . For example: the third radiation part  33  is disposed opposite to the first radiation part  31 , and the fourth radiation part  34  is disposed opposite to the second radiation part  32 . Each radiation part has a triangular contour, and each radiation element  301  has a triangular plate-shaped structure. That is, each radiation structure  3  is composed of  8  radiation elements  301  having the triangular plate-shaped structure. With continued reference to  FIG.  1   , the 8 triangular plate-shaped radiation elements  301  in each radiation structure  3  are spaced apart from each other to define a double-cross shaped opening (i.e., this opening having a shape of a “*”or of an asterisk), with two horizontally arranged triangular plate-shaped radiation elements  301  connected to the first microstrip line  4 , and two vertically arranged triangular plate-shaped radiation elements  301  connected to the second microstrip line  5 . A feed end  41  of the first microstrip line  4  corresponds to horizontal polarization, and a feed end  51  of the second microstrip line  5  corresponds to vertical polarization. In some examples, a distance between the two radiation elements  301  in each radiation part is d1, a distance between adjacent radiation parts in each radiation structure  3  is d2, and d2&gt;d1. Such arrangement is provided because the first microstrip line  4  has a feed direction different from that of the second microstrip line  5 , and interference between the feed lines in the two polarization directions is avoided by appropriately setting the distance between the radiation parts. 
       FIG.  6    is a S11 parameter graph (including two S11 parameter curves) of the feed end  41  of the first microstrip line  4  and the feed end  51  of the second microstrip line  5  of the antenna unit  10  in  FIG.  2   . The feed end  41  of the first microstrip line  4  and the feed end  51  of the second microstrip line  5  each have an impedance bandwidth of 1.5 GHz (from 3 GHz to 4.5 GHz, S11&lt;−10 dB)/1.5 GHz (from 3 GHz to 4.5 GHz, S11&lt;−6 dB), and a center frequency of 3.82 GHz, as shown by m1 and m2 in  FIG.  6   .  FIG.  7   a    is a planar radiation pattern obtained by exciting the feed end  41  of the first microstrip line  4  of the antenna unit  10  in  FIG.  2    when f=3.75 GHz. As shown in  FIG.  7   a   , at the frequency of 3.75 GHz, a gain (at 0°/90°) of the antenna unit  10  obtained by exciting the feed end  41  of the first microstrip line  4  is 3.37 dBi/−6.12 dBi, and a half-power beamwidth (which may also be referred to as a half-power lobe width) thereof is 92°/74°.  FIG.  7   b    is a planar radiation pattern obtained by exciting the feed end  51  of the second microstrip line  5  of the antenna unit  10  in  FIG.  2    when f=3.75 GHz. As shown in  FIG.  7   b   , a gain (at 0°/90°) of the antenna unit  10  obtained by exciting the feed end  51  of the second microstrip line  5  is −6.10 dBi/3.35 dBi, and a half-power beamwidth thereof is 92°/74°. 
     In some examples,  FIG.  8    is a schematic diagram of another antenna according to an embodiment of the present disclosure. As shown in  FIG.  8   , the antenna includes four antenna units  10  as described above, and further includes a first feed structure  6  and a second feed structure  7 , and a ratio of the width of each antenna unit  10  of that antenna to a distance from the antenna unit  10  to an adjacent antenna unit  10  is about 2:1, such as 1.9:0.95 to 1.8:0.85. The first feed structure  6  and the second feed structure  7  are both located on the second surface of the dielectric layer  1 . An orthogonal projection of the first feed structure  6  on the dielectric layer  1  overlaps at least partially an orthogonal projection of the first microstrip line  4  on the dielectric layer  1 , and the first feed structure  6  is configured to feed power to the first microstrip line  4 . An orthogonal projection of the second feed structure  7  on the dielectric layer  1  overlaps at least partially an orthogonal projection of the second microstrip line  5  on the dielectric layer  1 , and the second feed structure  7  is configured to feed power to the second microstrip line  5 . In one example, the first microstrip line  4  and the first feed structure  6  are arranged in a same layer. In this case, the first microstrip line  4  and the first feed structure  6  are directly electrically connected. The second microstrip line  5  and the second feed structure  7  are arranged in a same layer. In this case, the second microstrip line  5  and the second feed structure  7  are directly electrically connected. Alternatively, the first microstrip line  4  and the first feed structure  6  may be arranged in different layers, where the first feed structure  6  feeds power to the first microstrip line  4  in a coupling manner. Similarly, the second microstrip line  5  and the second feed structure  7  are arranged in different layers, where the second feed structure  7  feeds power to the second microstrip line  5  in a coupling manner. 
     In one example, when 2 n  slots  21  are provided in the reference electrode layer  2 , also 2 n  radiation structures  3  are provided. Meanwhile, the first feed structure  6  includes n levels of third microstrip lines  61 , and the second feed structure  7  includes n levels of fourth microstrip lines  71 . One 1st level third microstrip line  61  is connected to two adjacent first microstrip lines  4 , and different 1st level third microstrip lines  61  are connected to different first microstrip lines  4 . One m th  level third microstrip line  61  is connected to two adjacent (m−1) th  level third microstrip lines  61 , and different m th  level third microstrip lines  61  are connected to different (m−1) th  level third microstrip lines  61 . One 1st level fourth microstrip line  71  is connected to two adjacent second microstrip lines  5 , and different 1st level fourth microstrip lines  71  are connected to different second microstrip lines  5 . One m th  level fourth microstrip line  71  is connected to two adjacent (m−1) th  level fourth microstrip lines  71 , and different m th  level fourth microstrip lines  71  are connected to different (m−1) th  level fourth microstrip lines  71 . In the above, n≥2, 2≤m≤n, and m and n are both integers. 
     Taking the antenna shown in  FIG.  8    as an example, the antenna includes 4 radiation structures  3 , where n is 2. In other words, the first feed structure  6  includes 3 third microstrip lines  61  in 2 levels, and the second feed structure  7  includes 3 fourth microstrip lines  71  in 2 levels. One 1st level third microstrip line  61  is connected to feed ends  41  of the 1st and 2nd first microstrip lines  4  from left to right, and the other 1st level third microstrip line  61  is connected to feed ends  41  of the 3rd and 4th first microstrip lines  4  from left to right; and the 2nd level third microstrip line  61  is connected to the feed ends of the two 1st level third microstrip lines  61 . Similarly, one 1st level fourth microstrip line  71  is connected to feed ends  51  of the 1st and 2nd second microstrip lines  5  from left to right, and the other 1st level fourth microstrip line  71  is connected to feed ends  51  of the 3rd and 4th second microstrip lines  5  from left to right; and the 2nd level fourth microstrip line  71  is connected to the feed ends of the two 1st level fourth microstrip lines  71 . In this case, the feed end of the 2nd level third microstrip line  61  in the first feed structure  6  (i.e., the feed end  62  of the first feed structure  6 ) corresponds to horizontal polarization, and the feed end of the 2nd level fourth microstrip line  71  in the second feed structure  7  (i.e., the feed end  72  of the second feed structure  7 ) corresponds to vertical polarization. 
       FIG.  9    is a S11 parameter graph (including two S11 parameter curves) of the feed end  62  of the first feed structure  6  and the feed end  72  of the second feed structure  7  of the antenna shown in  FIG.  8   . The feed end  62  of the first feed structure  6  has an impedance bandwidth of 1.08 GHz (from 3.42 GHz to 4.5 GHz, S11&lt;−10 dB)/1.5 GHz (from 3 GHz to 4.5 GHz, S11&lt;−6 dB), as shown by m3 in  FIG.  9   , and the feed end  72  of the second feed structure  7  has an impedance bandwidth of 1.5 GHz (from 3 GHz to 4.5 GHz, S11&lt;−10 dB)/1.5 GHz (from 3 GHz to 4.5 GHz, S11&lt;−6 dB), as shown by m4 in  FIG.  9   .  FIG.  10   a    is a planar radiation pattern obtained by exciting the feed end  62  of the first feed structure  6  of the antenna in  FIG.  8    when f=3.75 GHz. As shown in  FIG.  10   a   , a gain (at 0°/90°) of the antenna unit  10  obtained by exciting the feed end  62  of the first feed structure  6  is 8.90 dBi/−2.23 dBi, and a half-power beamwidth thereof is 67°/19°.  FIG.  10   b    is a planar radiation pattern obtained by exciting the feed end  72  of the second feed structure  7  of the antenna in  FIG.  8    when f=3.75 GHz. As shown in  FIG.  10   b   , at the frequency of 3.75 GHz, a gain (at 0°/90°) of the antenna unit  10  obtained by exciting the feed end  72  of the second feed structure  7  is −4.37 dBi/9.21 dBi, and a half-power beamwidth thereof is 17°/64°. 
     In some examples,  FIG.  11    is a top view of another antenna according to an embodiment of the present disclosure. As shown in  FIG.  11   , this antenna has substantially the same structure as the antenna shown in  FIG.  8   , except that the antenna units  10  of this antenna are rotated by 45° as a whole compared with the antenna units  10  of the antenna in  FIG.  8   . Specifically, the reference electrode layer  2  of the antenna includes a body part  22 , a first branch  23  and a second branch  24 , and the first branch  23  and the second branch  24  are respectively connected to two sides of the body part  22  in a lengthwise direction of the body part  22 . The antenna further includes a fifth microstrip line  8  connected to the feed end  62  of the first feed structure  6 , and a sixth microstrip line  9  connected to the feed end  72  of the second feed structure  7 . An orthogonal projection of the fifth microstrip line  8  on the dielectric layer  1  is located in an orthogonal projection of the first branch  23  on the dielectric layer  1 . An orthogonal projection of the sixth microstrip line  9  on the dielectric layer  1  is located in an orthogonal projection of the second branch  24  on the dielectric layer  1 . A perpendicular bisector of a width of the body part  22  coincides with one diagonal line of the dielectric layer  1 . An extending direction of the fifth microstrip line  8  is perpendicular to an extending direction of the sixth microstrip line  9 , and an angle between the extending direction of each of the fifth and sixth microstrip lines and the diagonal line of the dielectric layer  1  is 45°. Taking  FIG.  11    as an example, a feed end of the fifth microstrip line  8  corresponds to +45° polarization, and a feed end of the sixth microstrip line  9  corresponds to −45° polarization. That is, the antenna shown in  FIG.  11    can realize polarization of ±45°. 
       FIG.  12    is a S11 parameter graph (including two S11 parameter curves) of the feed end of the fifth microstrip line  8  and the feed end of the sixth microstrip line  9  of the antenna unit  10  in  FIG.  11   . The feed end of the fifth microstrip line  8  and the feed end of the sixth microstrip line  9  each have an impedance bandwidth of 1.5 GHz (from 3 GHz to 4.5 GHz, S11&lt;−10 dB)/1.5 GHz (from 3 GHz to 4.5 GHz, S11&lt;−6 dB), as shown by m5 and m6 in  FIG.  12   .  FIG.  13   a    is a planar radiation pattern obtained by exciting the feed end of the fifth microstrip line  8  of the antenna in  FIG.  11    when f=3.75 GHz. As shown in  FIG.  13   a   , a gain (at −45°/45°) of the antenna unit  10  obtained by exciting the feed end of the fifth microstrip line  8  is −3.77 dBi/8.26 dBi, and a half-power beamwidth thereof is 70°/15°.  FIG.  13   b    is a planar radiation pattern obtained by exciting the feed end of the sixth microstrip line  9  of the antenna in  FIG.  11    when f=3.75 GHz. As shown in  FIG.  13   b   , at the frequency of 3.75 GHz, a gain (at −45°/45°) of the antenna unit  10  obtained by exciting the feed end of the sixth microstrip line  9  is 9.50 dBi/−7.48 dBi, and a half-power beamwidth thereof is 17°/62°. 
     In some examples,  FIG.  14    is a top view of another antenna according to an embodiment of the present disclosure. As shown in  FIG.  14   , this antenna has substantially the same structure as the antenna shown in  FIG.  2   , except the structure of the reference electrode layer  2 . Specifically, the antenna shown in  FIG.  14    may be divided into a radiation region Q 1  and feed regions Q 21  and Q 22 . The radiation structure  3  is located in the radiation region Q 1 , the first feed structure  6  is located in the feed region Q 21 , and the second feed structure  7  is located in the feed region Q 22 . The reference electrode layer includes not only the slot  21  in the radiation region but also an auxiliary slot  22  located in each of the feed regions Q 21  and Q 22 , and an orthogonal projection of the auxiliary slot  22  on the dielectric layer  1  does not overlap orthogonal projections of the first feed structure  6  and the second feed structure  7  on the dielectric layer  1 . In addition, an outer contour of part of the reference electrode layer  2  in the feed region Q 21  is the same as an outer contour of the first feed structure  6 , and an outer contour of part of the reference electrode layer  2  in the feed region Q 22  is the same as an outer contour of the second feed structure  7 . The auxiliary slot  22  can not only improve the optical transmittance of the antenna, but also change the radiation direction of the microwave signal. It should be noted here that a total area of the auxiliary slots  22  in the reference electrode layer may be as large as possible, as long as it is ensured that the orthogonal projection of the reference electrode layer  2  on the dielectric layer  1  overlaps and covers the orthogonal projections of the first feed structure  6  and the second feed structure  7  on the dielectric layer  1 . 
     In some examples, the reference electrode layer  2 , the first microstrip line  4 , the second microstrip line  5 , the third microstrip line  61 , the fourth microstrip line  71 , the fifth microstrip line, the sixth microstrip line  9  and the radiation element  301  each include, but are not limited to, a material of aluminum or copper. 
     In summary, the antenna in any one of the foregoing embodiments of the present disclosure is mainly directed to 5G base station communication and mobile communication applications in the frequency bands of n77 (from 3.3 GHz to 4.2 GHz) and n78 (from 3.3 GHz to 3.8 GHz), and adopts a design of a double-cross shaped slot rectangular radiation structure  3  having a rectangular slot and a combination of two-way symmetric feed lines, which is combined with the use of a transparent flexible base material, and makes the antenna unit  10  and the array have technical features such as wide bandwidth, high gain, miniaturization, dual polarization, partial transparency, good conformality, and the like. 
     In a second aspect, an embodiment of the present disclosure provides a method for manufacturing an antenna, which may be used for manufacturing the antenna according to any one of the embodiments as described above. The manufacturing method in the embodiment of the present disclosure includes the following steps S1 to S3. Step S1 includes providing a dielectric layer  1 . 
     The dielectric layer  1  may be a flexible substrate or a glass substrate, and step S1 may include a step of cleaning the dielectric layer  1 . 
     Step S2 includes forming a pattern including a reference electrode layer  2  on a first surface of the dielectric layer  1  through a patterning process. A slot  21  is formed in the reference electrode layer  2 . 
     In some examples, step S2 may specifically include: depositing a first metal film on the first surface of the dielectric layer  1  in a manner including, but not limited to, magnetron sputtering; nest, coating a photoresist thereon that is subjected to exposing and developing, and then performing wet etching; and stripping the photoresist after etching, to form the pattern including a reference electrode layer  2 . 
     S3 includes forming a pattern including a radiation structure  3 , a first microstrip line  4  and a second microstrip line  5  on a second surface of the dielectric layer  1  through a patterning process. An orthogonal projection of one radiation structure  3  on the dielectric layer  1  is located in an orthogonal projection of the slot  21  on the dielectric layer  1 . 
     The radiation structure  3  has a structure shown in  FIG.  2   , and includes a plurality of radiation parts spaced apart from each other, each of which includes radiation elements  301  spaced apart from each other. For example: the radiation parts in each radiation structure  3  include at least a first radiation part  31  and a second radiation part  32 ; and in this case, the first radiation part  31  and the second radiation part  32  each include radiation elements  301  spaced apart from each other. It should be noted that, in the embodiment of the present disclosure, the description is made by taking the case where two radiation elements  301  spaced apart from each other are included in each radiation part as an example, but it will be appreciated that the number of radiation parts in each radiation part is not limited to two, and may be specifically set according to the performance requirement of the antenna. 
     Apparently, in some examples, the radiation element  301  and the first and second microstrip lines  4 ,  5  may be manufactured through two separate patterning processes. 
     In some examples, step S3 may specifically include depositing a second metal film on the first surface of the dielectric layer  1  in a manner including, but not limited to, magnetron sputtering; next, coating a photoresist thereon that is subjected to exposing and developing, and then performing wet etching; and stripping the photoresist after etching, to form the pattern including the radiation structure  3 , the first microstrip line  4  and the second microstrip line  5 . 
     It should be noted here that the above steps S2 and S3 are exchangeable in the manufacturing sequence. That is, the radiation structure  3 , the first microstrip line  4  and the second microstrip line  5  may be formed on the second surface of the dielectric layer  1 , and then the reference electrode layer  2  is formed on the first surface of the dielectric layer  1 , which is also within the protection scope of the embodiment of the present disclosure. 
     In some examples, as shown in  FIG.  3   , the dielectric layer  1  in the embodiment of the present disclosure includes a first sub-dielectric layer  11 , a first bonding layer  12 , a second sub-dielectric layer  13 , a second bonding layer  14 , and a third sub-dielectric layer  15 , which are sequentially stacked on top of each other. A surface of the first sub-dielectric layer  11  distal to the first bonding layer  12  serves as the first surface of the dielectric layer  1 . A surface of the third sub-dielectric layer  15  distal to the second bonding layer  14  serves as the second surface of the dielectric layer  1 . In other words, the reference electrode layer  2  is formed on a side of the first sub-dielectric layer  11  distal to the first bonding layer  12 , and the radiation structure  3 , the first microstrip line  4  and the second microstrip line  5  are formed on a side of the third sub-dielectric layer  15  distal to the second bonding layer  14 . Alternatively, as shown in  FIG.  4   , the reference electrode layer  2  may be formed on a side of the first sub-dielectric layer  11  proximal to the first bonding layer  12 , and the radiation structure  3 , the first microstrip line  4  and the second microstrip line  5  may be formed on a side of the third sub-dielectric layer  15  proximal to the second bonding layer  14 . 
     In addition, in an embodiment of the present disclosure, the antenna structure includes not only the dielectric layer  1 , the reference electrode layer  2 , the radiation structure  3 , the first microstrip line  4 , and the second microstrip line  5  formed as described above, but also a first feed structure  6 , a second feed structure  7 , or other elements formed on the second surface of the dielectric layer  1 , which are not enumerated here. 
     It will be appreciated that the above implementations are merely exemplary implementations for the purpose of illustrating the principle of the disclosure, and the disclosure is not limited thereto. It will be apparent to one of ordinary skill in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and essence of the present disclosure. Such modifications and variations should also be considered as falling into the protection scope of the present disclosure.