Patent Publication Number: US-11658409-B2

Title: Antenna structure

Description:
RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 16/219,918, filed Dec. 13, 2018, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Technical Field 
     The invention relates to an antenna structure, and more particularly to an antenna structure that is capable of switching its radiation pattern. 
     Description of Related Art 
     With the vigorous development of communication technologies, commercial mobile communication systems can achieve high-speed data transmission, and provide Internet service providers with a wide range of services, such as network services of multimedia video streaming, instant road reporting and navigation, and instant network communication that require huge data transmission quantity. For hardware, an antenna design affects the performance of the wireless signals transmitting and receiving. Further, the conventional antenna does not have radiation pattern switching functions, and therefore its performance tends to be limited due to its surrounding environment. Therefore, how to design a high-performance antenna is one of the goals in the related industries. 
     SUMMARY 
     The objective of the invention is to provide an antenna structure that has radiation pattern switching functions of switching its radiation pattern based on its surrounding environment, thus achieving high transmission and reception performances under various environments. 
     One aspect of the invention relates to an antenna structure which includes a substrate, a horizontal radiator and a vertical radiator. The horizontal radiator on or in the substrate. The vertical radiator is in the substrate and includes a vertical conductor, plural planar metal structures and a switch. The planar metal structures are electrically connected through the at least one vertical conductor. The switch is in a gap of the planar metal structures and is coupled to at least one of the planar metal structures for switching a current distribution of the vertical radiator. 
     Another aspect of the invention relates to an antenna structure which includes a substrate, a horizontal radiator, a vertical radiator and a metal branch. The horizontal radiator is on or in the substrate. The vertical radiator is in the substrate and includes a vertical conductor and plural planar metal structures. The planar metal structures are electrically connected through the vertical conductor. The metal branch is selectively coupled to the vertical radiator. 
     Another aspect of the invention relates to an antenna structure which includes a substrate, a horizontal radiator, a vertical radiator and a metal branch. The horizontal radiator is on or in the substrate. The vertical radiator is in the substrate and includes a vertical conductor and plural planar metal structures. The planar metal structures are electrically connected through the vertical conductor. The switch is in a gap of the planar metal structures and is coupled to at least one of the planar metal structures for switching a current distribution of the vertical radiator. The metal branch is selectively coupled to the vertical radiator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments and advantages thereof can be more fully understood by reading the following description with reference made to the accompanying drawings as follows: 
         FIG.  1 A  and  FIG.  1 B  are respectively a perspective view and a top-view of an antenna structure in accordance with some embodiments of the invention. 
         FIG.  2    is a cross sectional view of the antenna structure in  FIG.  1 A . 
         FIG.  3    is a partial structural diagram of an antenna structure in accordance with some embodiments of the invention. 
         FIG.  4    exemplarily illustrates a partial planar diagram of the antenna structure in  FIG.  3   . 
         FIG.  5    exemplarily illustrates a partial perspective diagram of the antenna structure in  FIG.  3   . 
         FIG.  6    is a partial structural diagram of an antenna structure in accordance with some other embodiments of the invention. 
         FIG.  7    exemplarily illustrates a partial planar diagram of the antenna structure in  FIG.  6   . 
         FIG.  8    is a partial structural diagram of an antenna structure in accordance with some other embodiments of the invention. 
         FIG.  9    exemplarily illustrates a partial perspective diagram of the antenna structure in  FIG.  8   . 
     
    
    
     DETAILED DESCRIPTION 
     The spirit of the disclosure is clearly described hereinafter accompanying with the drawings and detailed descriptions. After realizing preferred embodiments of the disclosure, any persons having ordinary skill in the art may make various modifications and changes according to the techniques taught in the disclosure without departing from the spirit and scope of the disclosure. 
     Terms used herein are only used to describe the specific embodiments, which are not used to limit the claims appended herewith. Unless limited otherwise, the term “a,” “an,” “one” or “the” of the single form may also represent the plural form. Further, the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. 
     The document may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
     Further, spatially relative terms, such as “over,” “on,” “under,” “below,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. 
     Referring to  FIG.  1 A  and  FIG.  1 B ,  FIG.  1 A  and  FIG.  1 B  are respectively a perspective view and a top-view of an antenna structure  100 . The antenna structure  100  include at least a substrate  110  and components disposed on or in the substrate  110 , such as radiation elements, conductive lines, switches and/or other components. The substrate  110  has a center area  110 A and a peripheral area  110 B. The center area  110 A has components for transmitting electrical signals, while the peripheral area  110 B has radiators. 
       FIG.  2    is a cross sectional view of the antenna structure  100  in  FIG.  1 A . As shown in  FIG.  2   , the substrate  110  is a multi-layered board structure formed of alternately stacked dielectric layers  112  and metal layers  114 . Each dielectric layer  112  may be formed from FR4 material, glass, ceramic, epoxy resin or silicon, and each metal layer  114  may be formed from copper, aluminum, nickel and/or another material. In addition, each metal layer  114  may include a radiator element, a conductive line, a switch or another component needed to form a radiation structure and an electrical signal transmission structure. The metal layers  114  may include different patterns based on the components formed in the metal layers  114 . Moreover, the substrate  110  may be formed by various processes, such as low-temperature cofired ceramic (LTCC), integrated passive device (IPD), multi-layered film, multi-layered printed circuit board (PCB) or another multi-layered process based on the material type of the dielectric layers  112 . 
       FIG.  3    is a partial structure diagram of an antenna structure  300  in accordance with some embodiments of the invention. As shown in  FIG.  3   , the conductive lines, the conductive via structures  314  and/or another component are arranged in a center area  310 A of a substrate  310 , and a vertical radiator  320  and a horizontal radiator  330  are arranged in a peripheral area  310 B of the substrate  310  for collectively forming a monopole antenna or a dual-polarized antenna. The substrate  310  may be a multi-layered board structure similar to the structure formed of alternately stacked dielectric layers  112  and metal layers  114  as illustrated in  FIG.  2   . 
     The vertical radiator  320  may be vertically across multiple dielectric layers in the substrate  310 . The vertical radiator  320  includes vertical conductors  320 A, planar metal structures  320 B and switches  320 C. The vertical conductors  320 A extend along the direction perpendicular to the planar direction of the substrate  310 , and the planar metal structures  320 B extend along the planar direction of the substrate  310  and are electrically connected through the vertical conductors  320 A. In the embodiments, the distance between the adjacent vertical conductors  320 A is less than a quarter of the equivalent wavelength of the electromagnetic wave in the substrate  310 . As shown in  FIG.  3   , in some embodiments, the vertical conductors  320 A not only have the same length but also have the same height position in the substrate  310 . In another embodiment, the vertical conductors  320 A may have different lengths and/or different height positions. 
     In some embodiments, the vertical conductors  320 A are formed of through substrate via (TSV) conductors. In practical, the TSV conductors may be conductive by coating conductive liquid/paint or plating conductive metal in the fabricating process. 
     The conductive via structures  314  and the vertical conductors  320 A may be formed of one or more types. As shown in  FIG.  3   , the conductive via structures  314  include blind via structures and buried via structures, and the vertical conductors  320 A are blind via structures. However, embodiments of the invention are not limited thereto. In various embodiments, the conductive via structures  314  and/or the vertical conductors  320 A may include blind via structures, buried via structures and/or through via structures, which can be determined according to design requirements. 
     In addition, the conductive via structures  314  and the vertical conductors  320 A may be plated conductive via structures, in which conductive material is plated onto the walls of the via holes, such as copper, gold, aluminum, nickel or another metal, and then a conductive material or an insulating material (e.g. air or epoxy resin) is filled or plugged into the remained spaces, or a conductive material or an insulating material is plugged to form plugged via structures, or a solder mask is disposed on the top and/or the bottom of the spaces to form tented via structures. In another embodiment, the conductive via structures  314  and the vertical conductors  320 A may be non-plated conductive via structures, in which conductive material is directly filled into the via holes, such as metal of copper, gold, aluminum, nickel, but are not limited thereto. 
     The planar metal structures  320 B may respectively belong to several metal layers in the substrate  310 . The longitudinal direction of the planar metal structures  320 B is the horizontal direction of the main beam of the vertical radiator  320 . As shown in  FIG.  3   , in some embodiments, the lengths of the planar metal structures  320 B are the same and larger than a quarter of the equivalent wavelength of the electromagnetic wave in the substrate  310 . In another embodiment, the lengths of the planar metal structures  320 B may be different, and the largest length among the planar metal structures  320 B is larger than a quarter of the equivalent wavelength of the electromagnetic wave in the substrate  310 . In addition, in some embodiments, as shown in  FIG.  3   , the planar metal structures  320 B are metal strips. In another embodiment, the planar metal structures  320 B may have a metal plate with one or more open slots, a combination of the aforementioned metal strip and metal plate, or another suitable metal structure. 
     The planar metal structures  320 B may have one or more planar patterns. For the embodiments of  FIG.  3   , the first planar metal structure  320 B (i.e. the first of the planar metal structure  320 B from below) has two gaps, and each of the second to fourth planar metal structures  320 B has a gap. The switches  320 C are respectively in the gaps of the second to fourth planar metal structures  320 B. According to the arrangement of the vertical conductors  320 A in the substrate  310 , the widths of some or all of the gaps may be smaller than the distance between two adjacent vertical conductors  320 A, or alternatively the widths of some or all of the gaps may be larger than the distance between two adjacent vertical conductors  320 A. The status of the switch  320 C can be controlled to determine whether the metal structures respectively between the two terminals of the switch  320 C are electrically connected directly through the switch  320 C. When the switch  320 C is turned on, the metal structures at the two ends of the switch  320 C are electrically connected directly through the switch  320 C, i.e. a current flowing through the switch  320 C exists. Oppositely, when the switch  320 C is turned off, the metal structures at the two ends of the switch  320 C are not electrically connected directly through the switch  320 C, i.e. the current in the vertical radiator  320  is blocked from flowing through the switch  320 C. Because the current distribution determines the radiation pattern generated by the vertical radiator  320 , the antenna gain and the radiation pattern of the vertical radiator  320 , including main beam direction, half-power beam width (HPBW) and directivity, can be determined by controlling the on and off statuses of each switch  320 C. For the embodiments of  FIG.  3   , the direction of the main beam of the radiation pattern generated by the vertical radiator  320  when each switch  320 C is turned on is upper than that when each switch  320 C is turned off. Therefore, the radiation pattern of the antenna structure  300  can be switched by turning on or turning off each switch  320 C. 
     In accordance with the type and fabrication process of the substrate  310 , each switch  320 C may be a diode, a field effect transistor (FET), a metal oxide semiconductor (MOS) FET, or a combination thereof, but is not limited thereto. 
     The horizontal radiator  330  is a planar metal plate structure, and the length thereof may be approximately a quarter of the equivalent wavelength of the electromagnetic wave in the substrate  310 . The horizontal radiator  330  and one of the planar metal structures  320 B may be coplanar, i.e. belong to the same metal layer in the substrate  310 , determining the vertical direction of the main beam of the vertical radiator  320 . 
     As shown in  FIG.  3   , the vertical radiator  320  is closer to the side edge  310 E of the substrate  310  than the horizontal radiator  330 . In another embodiment, the horizontal radiator  330  may be closer to the side edge  310 E of the substrate  310  than the vertical radiator  320 , or else the distance between the horizontal radiator  330  and the side edge  310 E of the substrate  310  is similar to that between the vertical radiator  320  and the side edge  310 E of the substrate  310 . 
     The vertical radiator  320  and the horizontal radiator  330  are electrically coupled to the conductive lines  312 , the conductive via structures  314  and/or another component in the substrate  310  and in the center area  310 A respectively through the feeding traces  322 ,  332 . The feeding trace  322  and one of the planar metal structures  320 B may belong to the same metal layer in the substrate  310 , and the feeding trace  332  and the horizontal radiator  330  may belong to the same metal layer in the substrate  310 . The feeding traces  322 ,  332  may be parallel microstrip line structures or other transmission line structures. 
     In addition, a chip  340  is further disposed over the center area  310 A of the substrate  310 , and the side surface of the chip  340  toward the substrate  310  has metal bumps  342  thereon. By bonding the metal bumps  342  to the bonding pads  316  on the substrate  310 , the chip  340  can be mounted on the substrate  310  to have the components in the chip  340  and the conductive lines  312 , the conductive via structures  314  and/or other components in the substrate  310  electrically connected with each other, such that the chip  340  is electrically connected with the vertical radiator  320  and the horizontal radiator  330 . The metal bumps  342  may be gold bumps, tin bumps or other bumps formed from another metal or metal alloy. 
     The chip  340  has an RFIC and/or other active and/or passive components for constituting a transmitting and/or receiving circuit. The chip  340  may be bonded to the substrate  310  by such as ball grid array (BGA) packaging, chip scale packaging (CSP), flip chip packaging, wafer-level packaging, or another suitable packaging method, such that the components in the chip  340  and in and and/or on the substrate  310  are electrically connected with each other. 
     In another embodiment, the antenna structure  300  may only include the substrate  310  and the components in the substrate  310 , e.g., the vertical radiator  320  and the horizontal radiator  330 , without including the chip  340  and the metal bumps  342 . 
     In addition, in some embodiments, a reflective wall structure (not shown) may be arranged between the area of the vertical radiator  320  and the horizontal radiator  330  and the center area  310 A for increasing the directivity of the beam generated by the vertical radiator  320  and the horizontal radiator  330  and blocking radiation waves from interfering the components in the center area  310 A. Similar to the structure formed of the vertical conductors  320 A of the vertical radiator  320  and the planar metal structures  320 B, the reflective wall structure may be formed of electrically conductive via structures, but the extending directions of the reflective wall structure are approximately parallel to the corresponding side edges  310 E. 
     Furthermore, in some embodiments, a broadband antenna set (not shown) may further be disposed in the antenna structure  300  and be formed of phased array antennas arranged on a side of the chip  340  far away from the substrate  310  for generating a multi-beam array with angles with respect to the planar direction of the substrate  310 . The broadband antenna set may be electrically connected with the conductive lines  312 , the conductive via structures  314  and/or another component in the center area  310 A. 
       FIG.  4    exemplarily illustrates a partial planar diagram of the antenna structure  300 . In the vertical radiator  320  shown in  FIG.  4   , the vertical conductors  320 A are respectively the vertical conductors  320 A shown in  FIG.  3   , and the planar metal structure  320 B is one of the planar metal structures  320 B shown in  FIG.  3   . The angle θ between the longitudinal direction of the planar metal structures  320 B and the longitudinal direction of the horizontal radiator  330  is an obtuse angle. As such, the generated radiation pattern may further include a horizontal polarization component perpendicular to the longitudinal direction of the planar metal structure  320 B. In other embodiments, according to practical application requirements, the angle θ between the longitudinal direction of the planar metal structures  320 B and the longitudinal direction of the horizontal radiator  330  may be modified to be a right angle or an acute angle, or otherwise the longitudinal direction of the planar metal structures  320 B may be parallel to the longitudinal direction of the horizontal radiator  330 . 
       FIG.  5    exemplarily illustrates a partial perspective diagram of the antenna structure  300 . In the vertical radiator  320  shown in  FIG.  5   , the vertical conductors  320 A are respectively the vertical conductors  320 A shown in  FIG.  3   , and the planar metal structures  320 B are adjacent upper and lower ones of the planar metal structures  320 B shown in  FIG.  3   . As shown in  FIG.  5   , the switch  320 C is in the gap of the lower planar metal structure  320 B. When the switch  320 C is turned on, each of the upper and lower planar metal structures  320 B has a complete current path. Oppositely, when the switch  320 C is turned off, because the metal structures at the two ends of the switch  320 C have to be electrically connected through the vertical conductors  320 A and the upper planar metal structure  320 B (or another planar metal structure other than the upper and lower ones in  FIG.  5   ) rather than directly through the switch  320 C, the upper planar metal structure  320 B still has a complete current path, but the lower planar metal structure  320 B does not have a complete current path, such that the overall current distribution of the vertical radiator  320  is changed accordingly. The overall current distribution of the vertical radiator  320  may be changed by switching the on and off statuses of the switch  320 C, so as to switch the radiation pattern of the vertical radiator  320 . 
       FIG.  6    is a schematic diagram of an antenna structure  300 ′ in accordance with some other embodiments of the invention. In comparison with the antenna structure  300  of  FIG.  3   , the antenna structure  300 ′ of  FIG.  6    further includes a metal branch  324 , and in  FIG.  6   , the switch  320 C is coupled between the metal branch  324  and one of the planar metal structures  320 B for controlling whether the metal branch  324  and the planar metal structure  320 B are electrically connected or not, and none of the gaps of the planar metal structure  320 B has a switch  320 C. The other components of the antenna structure  300 ′ are respectively the same as the corresponding components of the antenna structure  300  in  FIG.  3   , and therefore the related description can be referred to the foregoing paragraphs and is not repeated herein. 
       FIG.  7    is exemplarily illustrates a partial planar diagram of the antenna structure  300 ′. In the vertical radiator  320  shown in  FIG.  7   , the vertical conductors  320 A are respectively the vertical conductors  320 A shown in  FIG.  6   , the planar metal structure  320 B is one of the planar metal structures  320 B shown in  FIG.  6   , the switch  320 C is the switch  320 C shown in  FIG.  7   , and the metal branch  324  is the metal branch  324  shown in  FIG.  6   . 
     In  FIG.  7   , the status of the switch  320 C can be controlled to determine whether the planar metal structure  320 B and the metal branch  324  respectively between the two terminals of the switch  320 C are electrically connected through the switch  320 C. When the switch  320 C is turned on, the planar metal structure  320 B and the metal branch  324  are electrically connected through the switch  320 C, and therefore the current in the planar metal structure  320 B partially flows through the metal branch  324 . Oppositely, when the switch  320 C is turned off, the metal structures at the two terminals of the switch  320 C are not electrically connected directly through the switch  320 C, and therefore the current in the vertical radiator  320  is blocked from flowing through the switch  320 C. Because the current distribution determines the radiation pattern generated by the vertical radiator  320 , and the longitudinal direction of the metal branch  324  is different from the longitudinal direction of the planar metal structure  320 B, the antenna gain and the radiation pattern of the vertical radiator  320 , including main beam direction, HPBW, directivity and polarization direction, can be determined by controlling the on and off statuses of the switch  320 C. In the embodiments of  FIG.  7   , the longitudinal direction of the metal branch  324  is perpendicular to the longitudinal direction of the planar metal structure  320 B. In other embodiments, according to practical application requirements, the longitudinal direction of the metal branch  324  may not be perpendicular to the longitudinal direction of the planar metal structure  320 B. Therefore, the radiation pattern and the polarization status of the antenna structure  300 ′ can be switched by turning on or turning off the switch  320 C. 
       FIG.  8    is a schematic diagram of an antenna structure  300 ″ in accordance with some other embodiments of the invention. In comparison with the antenna structure  300  in  FIG.  3    and the antenna structure  300 ′ in  FIG.  6   , the antenna structure  300 ″ in  FIG.  8    simultaneously includes the metal branch  324 , the switch in the gap of the planar metal structure  320 B and the switch between the planar metal structure  320 B and the metal branch  324 . The components in the antenna structure  300 ″ are respectively the same as the corresponding components of the antenna structure  300  in  FIG.  3    and/or the antenna structure  300 ′ in  FIG.  6   , and therefore the related description can be referred to the foregoing paragraphs and is not repeated herein. 
       FIG.  9    exemplarily illustrates a partial perspective diagram of the antenna structure  300 ″. In the vertical radiator  320  illustrated in  FIG.  9   , the vertical conductors  320 A are respectively the vertical conductors  320 A shown in  FIG.  8   , the planar metal structures  320 B are respectively adjacent upper and lower ones of the planar metal structures  320 B shown in  FIG.  8   , the switches  320 C are respectively two of the switches  320 C shown in  FIG.  8   , and the metal branch  324  is the metal branch  324 . The functions of the switch  320 C in a gap of the planar metal structure  320 B and the switch  320 C between the planar metal structure  320 B and the metal branch  324  are respectively the same as the switches  320 C in  FIG.  5    and  FIG.  7   . In addition, in the embodiments of  FIG.  9   , the angle ϕ between the longitudinal direction the metal branch  324  and the planar metal structures  320 B is an obtuse angle. In another embodiment, according to practical application requirements, the angle ϕ between the longitudinal direction of the metal branch  324  and the planar metal structures  320 B may be a right angle or an acute angle. Therefore, the radiation pattern and the polarization status of the antenna structure  300 ″ can be switched by turning on or turning off each switch  320 C. 
     It is noted that the arrangements of patterns, locations and quantities of the vertical conductors  320 A, the planar metal structures  320 B, the switches  320 C and the metal branch  324  shown in  FIG.  3    to  FIG.  9    are merely illustrative examples. For practical designs, the arrangements of patterns, locations and quantities of the vertical conductors  320 A, the planar metal structures  320 B, the switches  320 C and the metal branch  324  may be adjusted according to application requirements, but are not limited to the contents shown in  FIG.  3    to  FIG.  9   . 
     Summing up the above, the antenna structure of the invention has radiation pattern switching functions of switching its radiation pattern based on its surrounding environment, thus achieving high transmission and reception performances under various environments. 
     Although the invention is described above by means of the implementation manners, the above description is not intended to limit the invention. A person of ordinary skill in the art can make various variations and modifications without departing from the spirit and scope of the invention, and therefore, the protection scope of the invention is as defined in the appended claims.