Patent Publication Number: US-11646481-B2

Title: Multiple input multiple output antenna apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Continuation of International Application No. PCT/KR2018/004638, filed on Apr. 20, 2018, which claims the benefit of and priority to Korean Patent Application Nos. 10-2017-0051475, filed on Apr. 21, 2017 and 10-2018-0045883, filed on Apr. 20, 2018, the content of which are herein incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to an MIMO antenna apparatus, and more particularly, to an MIMO antenna apparatus, which may directly contact a heat-generation element for generating heat, thereby enhancing heat-dissipation performance, and eliminate assembling tolerance and height deviation with a peripheral component, thereby enhancing universality. 
     BACKGROUND ART 
     A wireless communication technology, for example, a Multiple Input Multiple Output (MIMO) technology, as a technology of significantly increasing the data transmission capacity by using a plurality of antennas, is a Spatial multiplexing technique in which a transmitter transmits different data from each other through each transmission antenna, and a receiver distinguishes the transmitted data through a proper signal processing. 
     Accordingly, as the number of transmission/reception antennas increases at the same time, the channel capacity may increase to allow more data to be transmitted. For example, it is possible to secure about 10 times the channel capacity by using the same frequency band compared to the current single antenna system if it is required to increase the number of antennas to 10. 
     In the case of a transceiver to which the Multiple Input Multiple Output (MIMO) technology has been applied, as the number of antennas increases, the number of transmitters and filters also increases, a predetermined heat is generated by the high output for expanding the coverage, and the external emission of the generated heat has a great impact on durability and antenna performance of the product. This heat-dissipation problem may be recognized as a common problem occurring in both a communication component mounted in a PCB and a heat-generation element for generating a predetermined heat. 
     Conventionally, a structure has been general in which one surface of a heat-dissipation body provided with a plurality of heat-dissipation fins indirectly contacts the heat-generation element by using a medium such as a thermal pad, and the heat generated from the heat-generation element is heat-dissipated to the outside through the heat-dissipation fin of the heat-dissipation body. 
     As described later, the thermal pad inevitably generates contact thermal resistance. Nevertheless, the reason why the thermal pad is provided to mediate between the heat-generation element and the heat-dissipation body is for allowing the heat-dissipation body to easily deliver the heat while eliminating the assembling tolerance necessary for installing to contact the heat-generation element of the PCB, the height deviation generated during soldering of the heat-generation element to the PCB, and the like. 
     However, the heat-dissipation structure according to the related art has had the difficulty in efficiently cooling the component by inevitably generating the contact thermal resistance between the heat-generation element and the heat-dissipation body by the thermal pad having a certain thickness, has had a problem of further increasing the contact thermal resistance in the case of increasing the thickness of the thermal pad in order to eliminate the above-described assembling tolerance, the height deviation, and the like, and in order to solve this problem, it is possible to change the design to increase the height of the heat-dissipation fin of the heat-dissipation body but a problem that increases the weight and size of the product is additionally caused by the design change, and in particular, there is a problem that reaches the saturation state where the component temperature does not lower even if the height of the heat-dissipation fin of the heat-dissipation body increases if the heat-generation amount is high. 
     Meanwhile, as the related art in the art to which the present disclosure pertains, there is Korean Patent Laid-Open Publication No. 2012-0029632 that discloses the contents of the lamp apparatus capable of efficiently emitting heat generated at the time of driving the lamp apparatus. 
     DISCLOSURE 
     Technical Problem 
     The present disclosure is intended to solve the above problems, and an object of the present disclosure is to provide a Multiple Input Multiple Output (MIMO) antenna apparatus, which may directly contact a heat-dissipation part to heat-generation elements, thereby enhancing heat-dissipation performance, and eliminate assembling tolerance and height deviation with a peripheral component, thereby enhancing universality, in the Multiple Input Multiple Output (MIMO) antenna apparatus provided with a heat-generation element such as a plurality of antenna elements and a communication component for electrically connecting them. 
     Technical Solution 
     A preferred embodiment of an MIMO antenna apparatus according to the present disclosure includes a PCB having at least one heat-generation element provided on one surface thereof, a first heat-dissipation part disposed to cover one surface of the PCB, having a through hole formed in a portion corresponding to the position provided with the heat-generation element, and having a plurality of vertical heat-dissipation fins formed to be extended in a direction perpendicular to the outside surface thereof, and a second heat-dissipation part detachably coupled to the through hole to contact one surface of the heat-generation element to receive heat from the heat-generation element and to dissipate heat at a long distance father than the first heat-dissipation part. 
     Here, the second heat-dissipation part may include a coupling body having one end portion coupled to be accommodated in the through hole, and a plurality of vertical heat-dissipation fins extended and formed to be perpendicular to the plurality of vertical heat-dissipation fins on the outer circumferential surface of the coupling body. 
     Further, a heat distribution space cut axially toward one end portion thereof may be formed on the other end portion of the coupling body, and a heat distribution bridge extending upwards from the bottom surface of the heat distribution space and having the horizontal cross section of a “+” shape may be formed inside the heat distribution space. 
     Further, the coupled body may be formed with a plurality air vent holes communicating the heat distribution space with the outside, and penetrating between the plurality of horizontal heat-dissipation fins. 
     Further, a plurality of screw fastening holes may be formed on the rim portion of one surface forming one end portion of the coupling body, the through hole may be provided with a plurality of fastening flanges protruded to the inside and having a screw through hole formed therein, and the coupling body may be screw-coupled to the plurality of fastening flanges by a fastening screw. 
     Further, the coupling body may have the one surface moved to the side at which the heat-generation element has been provided upon the coupling of the fastening screw. 
     Further, a tolerance absorption ring closely contacting the plurality of fastening flanges, respectively, by the head portion of the fastening screw upon the coupling of the fastening screw may be interposed on the outer circumferential surface of the fastening screw. 
     Further, the tolerance absorption ring may be made of an elastic material. 
     Further, the PCB may be coupled to the first heat-dissipation part by a fastening member so that the heat-generation element faces the through hole, and the tolerance absorption ring may be elastically deformed when the coupling force of the PCB to the first heat-dissipation part by the fastening member is provided. 
     Further, a female thread may be formed on the inner circumferential surface of the through hole, and a male thread fastened to the female thread may be formed on the outer circumferential surface of the coupling body inserted into the through hole. 
     Further, a guide boss extending the through hole to the outside and guiding the insertion of one end portion of the coupling body may be formed to be protruded on the other surface of the first heat-dissipation part having the plurality of vertical heat-dissipation fins formed thereon, and a locking ring screw-coupled to closely contact the front end portion of the guide boss may be provided on the outer circumferential surface of the coupling body. 
     Further, a sealing member for blocking a gap between the inner circumferential surface of the guide boss and the coupling body may be interposed on the outer circumferential surface of the coupling body, and the locking ring may press the sealing member when closely contacting the front end portion of the guide boss. 
     Further, the second heat-dissipation part may further include a heat conductive medium block coupled to one surface of the coupling body, and contacting one surface of the heat-generation element, and the heat conductive medium block may be made of a material having a higher thermal conductivity than that of the coupling body. 
     Further, the heat conductive medium block may be coupled to a coupling groove formed in a groove shape on one surface of the coupling body in any one method of a screw coupling method and a forcibly press-fitting method. 
     Further, the heat conductive medium block may be coupled to one surface of the coupling body in any one method among a bonding coupling method, a brazing coupling method, and a heterogeneous injection molding method. 
     Further, the heat conductive medium material may be applied to one surface of the coupling body contacting the heat-generation element. 
     Further, the plurality of horizontal heat-dissipation fins may be arranged in plural in multiple stages to be spaced at a predetermined distance apart from each other from the heat-generation element to the outside, and the appearance combination of the plurality of horizontal heat-dissipation fins may be formed to have any one among cylindrical, hexahedral, sphere, and cone shapes. 
     Further, the MIMO antenna apparatus may further include an air baffle for blocking the heat dissipated from the second heat-dissipation part provided at the lower side relatively from being delivered to the second heat-dissipation part provided at the upper side relatively by the rising airflow, if the second heat-dissipation part is coupled, by one, to each of the upper side and the lower side of one surface of the first heat-dissipation part disposed vertically. 
     Advantageous Effects 
     According to an embodiment of the MIMO antenna apparatus according to the present disclosure, in the Multiple Input Multiple Output (MIMO) antenna apparatus provided with the heat-generation element such as the plurality of antenna elements and a communication component for electrically connecting them, it is possible to directly contact the heat-dissipation part to the heat-generation elements to drastically reduce the contact thermal resistance generated during the heat delivery, thereby enhancing the heat-dissipation performance and increasing the lifespan of the apparatus, and to eliminate the assembling tolerance and the height deviation with the peripheral component, thereby enhancing universality. 
     Further, according to an embodiment of the MIMO antenna apparatus according to the present disclosure, it is possible to directly contact the heat-dissipation part to each of the heat-generation elements of the PCB on which the plurality of communication components have been mounted to eliminate the signal distortion or signal imbalance phenomenon due to the high heat generated in the plurality of communication components, thereby greatly enhancing communication performance. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is a perspective diagram illustrating a preferred embodiment of an MIMO antenna apparatus according to the present disclosure. 
         FIG.  2    is an exploded perspective diagram of  FIG.  1   . 
         FIG.  3    is an exploded perspective diagram illustrating a second heat-dissipation part in the configuration in  FIG.  1   . 
         FIG.  4    is a cross-sectional diagram taken along the line A-A in  FIG.  1   . 
         FIG.  5    is a cutout perspective diagram of the exploded state illustrating the coupling structure of the second heat-dissipation part to a PCB in the configuration in  FIG.  4   . 
         FIG.  6    is a perspective diagram illustrating an air baffle in the configuration in  FIG.  1   . 
         FIGS.  7 A to  7 C  are perspective diagrams illustrating various forms of the second heat-dissipation part in the configuration of the MIMO antenna apparatus according to the present disclosure. 
         FIGS.  8 A and  8 B  are heat distribution diagrams for comparing the heat-dissipation performance between the conventional heat-dissipation mechanism and the MIMO antenna apparatus according to the present disclosure. 
     
    
    
     BEST MODE 
     Advantages and features of the present disclosure, and a method for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below, but may be implemented in various different forms from each other, and only the present embodiments are provided to make the disclosure of the present disclosure complete, and to fully inform those skilled in the art to which the present disclosure pertains of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. The same components are denoted by the same reference numerals throughout the specification. 
     Hereinafter, an embodiment of an MIMO antenna apparatus according to the present disclosure will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a perspective diagram illustrating a preferred embodiment of an MIMO antenna apparatus according to the present disclosure, and  FIG.  2    is an exploded perspective diagram of  FIG.  1   . 
     A preferred embodiment of the MIMO antenna apparatus  1  according to the present disclosure, as illustrated in  FIGS.  1  and  2   , includes a Printed Circuit Board (PCB)  50  having at least one heat-generation element  51  provided on one surface thereof, a first heat-dissipation part  10  disposed to cover one surface of the PCB  50 , having a through hole  13  formed in a portion corresponding to the position provided with the heat-generation element  51 , and having a plurality of vertical heat-dissipation fins  12  formed to be extended in a direction perpendicular to the outside surface thereof, and a second heat-dissipation part  100  detachably coupled to the through hole  13  to directly contact one surface of the heat-generation element  51  to receive heat from the heat-generation element  51  and dissipating heat at a long distance farther than the first heat-dissipation part  10 . 
     Here, the heat-generation element  51  is a concept of including any element as long as it is an element that generates a predetermined heat while being driven by a power input. Specifically, communication components (for example, a transceiver, a filter, a Power Amplifier (PA), and the like) constituting a Multiple Input Multiple Output (MIMO) system capable of intensively constructing a fifth generation wireless communication technology by significantly increasing data transmission capacity by using a plurality of antennas may be a suitable example of a ‘heat-generation element.’ 
     Here, the MIMO system may be provided with a plurality of antenna elements, a digital processing circuit for controlling them, and a Power Supply Unit (PSU) provided to correspond to each to enable independent and individual control of each antenna element. 
     Meanwhile, as illustrated in  FIG.  2   , the first heat-dissipation part  10  has a predetermined thickness so that the PCB  50  is accommodated downwards in the figure, and includes a heat-dissipation part housing  11  that has a rectangular shape lengthily in one side and the other side direction, and has a rectangular parallelepiped shape having the lower surface opened in the figure. Hereinafter, for convenience of description, the lower portion of the first heat-dissipation part  10  in the figure is referred to as a ‘PCB accommodation space  5  (illustrated in  FIG.  4   ).’ 
     Here, the PCB  50  may be coupled to closely contact the inside surface of the PCB accommodation space  5  by the coupling force of a fastening member not illustrated. For example, the fastening member may be a fastening screw coupled to a fastening hole not illustrated formed on the inside surface of the PCB accommodation space  5 , and the PCB  50  may firmly, closely contact the inside surface of the PCB accommodation space  5  by the coupling force generated when the fastening screw is fastened to the fastening hole while penetrating the PCB  50 . 
     The above-described vertical heat-dissipation fin  12  is protruded to the outside, formed lengthily in the longitudinal direction, and multiple ones are disposed in parallel to be spaced at a predetermined distance apart from each other in the width direction perpendicular to the longitudinal direction in the figure on the upper surface of the heat-dissipation part housing  11  corresponding to the upper side in the figure. 
     Further, at least one through hole  13  communicating with the PCB accommodation space  5  may be formed on the upper surface of the heat-dissipation part housing  11 . A guide boss  14  may be formed on the upper surface of the heat-dissipation part housing  11  to be protruded upwards to extend the circumferential portion of the through hole  13 . 
     The guide boss  14  extends a predetermined length upwards from the upper surface of the heat-dissipation part housing  11 , is formed in a hollow cylindrical shape, has a shape with the through hole  13  extending upwards, and serves as a guide when the lower end portion of the second heat-dissipation part  100  is accommodated and coupled thereto in  FIGS.  1  and  2   . 
     Here, the upper end of the guide boss  14  may be formed to match the height of the plurality of vertical heat-dissipation fins  12  provided on the upper surface of the heat-dissipation part housing  11 . 
     Further, as illustrated in the right portion in  FIG.  2   , a cutout part  18  in which a portion of the adjacent plurality of vertical heat-dissipation fins  12  has been cut to be spaced apart from the guide boss  14  may be formed around the guide boss  14 . 
     However, the cutout part  18  is not necessarily formed, and as illustrated in the left portion in  FIG.  2   , it is natural that the plurality of vertical heat-dissipation fins  12  adjacent to the guide boss  14  may also be formed integrally with the guide boss  14 . 
     In an embodiment of the second heat-dissipation part  100  having the cutout part  18  formed therein, there is an advantage that independently dissipates the heat generated from the heat-generation element  51  to be heat-dissipated with the involvement of only the second heat-dissipation part  100 . On the contrary, in an embodiment of the second heat-dissipation part  100  in which the cutout part  18  is not formed and the plurality of vertical heat-dissipation fins  12  of the first heat-dissipation part  10  are formed integrally with the guide boss  14 , there is an advantage that appropriately distributes the heat generated from the heat-generation element  51  to the first heat-dissipation part  10  and the second heat-dissipation part  100  via the guide boss  14 , thereby enabling rapid heat dissipation. 
     Further, one surface on which the heat-generation element  51  has been mounted is accommodated and coupled to face the inside of the through hole  13  in the PCB accommodation space  5  of the heat-dissipation part housing  11  corresponding to the lower side in the figure. At this time, at least a portion of the heat-generation element  51  is preferably disposed to overlap the inside of the through hole  13 . 
     A plurality of fastening flanges  15  to which the second heat-dissipation part  100  may be screw-coupled by a fastening screw  114  may be provided to be protruded toward the center of the through hole  13  on the lower end portion of the inner circumferential surface of the through hole  13 . 
     A screw through hole  16  to which the fastening screw  114  is fastened may be perforated and formed vertically in the plurality of fastening flanges  15 . Further, a fastening groove  17  in which a head portion  114   b  of the fastening screw  114  is accommodated may be formed to be opened downwards on the lower surface of the plurality of fastening flanges  15  (see the reference numerals in  FIGS.  4  and  5   ). 
     Meanwhile, a preferred embodiment of the MIMO antenna apparatus  1  according to the present disclosure, as illustrated in  FIG.  2   , may further include a cover panel  40  coupled to shield the opened one surface of the heat-dissipation part housing  11 . The cover panel  40  is a configuration of serving as protecting the PCB  50  coupled to the inside of the PCB accommodation space  5  from the outside, and the coupling method to the heat-dissipation part housing  11  may be any method. The cover panel  40  may have a configuration corresponding to a radome for protecting the antenna elements if the above-described MIMO system is applied. 
       FIG.  3    is an exploded perspective diagram illustrating a second heat-dissipation part in the configuration in  FIG.  1   ,  FIG.  4    is a cross-sectional diagram taken along the line A-A in  FIG.  1   , and  FIG.  5    is a cutout perspective diagram of the exploded state illustrating the coupling structure of the second heat-dissipation part to the PCB in the configuration in  FIG.  4   . 
     In a preferred embodiment of the MIMO antenna apparatus  1  according to the present disclosure, as illustrated in  FIGS.  1  and  2   , the second heat-dissipation part  100  is coupled to the through hole  13  formed in the heat-dissipation part housing  11  to accommodate the lower end portion thereof. 
     As illustrated in  FIGS.  3  to  5   , the second heat-dissipation part  100  may include a coupling body  110  coupled to the through hole  13  formed in the heat-dissipation part housing  11  to accommodate one end portion (the lower end portion in the figure) thereof, and a plurality of horizontal heat-dissipation fins  130  extended and formed to be perpendicular to the above-described plurality of vertical heat-dissipation fins  12  on the outer circumferential surface of the coupling body  110 . 
     More specifically, the coupling body  110  is formed to have a cylindrical shape having a diameter of the size that may be inserted into the through hole  13 , and the plurality of horizontal heat-dissipation fins  130  may be formed to have a panel shape radially extending from the outer circumferential surface of the coupling body  110 , and disposed in multiple stages to be spaced at a predetermined distance apart from each other vertically. 
     As illustrated in  FIGS.  3  to  5   , a heat distribution space  111  axially cut toward the lower end portion thereof may be formed on the other end portion (the upper end portion in the figure) of the coupling body  110 . 
     The heat distribution space  111  is a space prepared to be evenly distributed along the outer circumferential surface of the coupling body  110  by reducing the vertical thickness of the lower end portion of the coupling body  110 , which is a portion that receives and delivers heat substantially. That is, the coupling body  110  is made of a material capable of heat conduction, but if the position where the heat distribution space  111  is formed has been fully filled, there is a possibility that non-uniformity of the heat delivery amount due to the thickness may occur. Here, if the heat generated from the heat-generation element  51  is delivered to the lower end portion of the coupling body  110 , the heat distribution space  111  serves as conducting it to the outer circumferential surface of the coupling body  110  provided with the plurality of horizontal heat-dissipation fins  130  quickly and evenly. 
     However, since the heat may be agglomerated in an insulated state by the empty space, which is the heat dissipation space  111 , in a preferred embodiment of the MIMO antenna apparatus  1  according to the present disclosure, as illustrated in  FIGS.  3  to  5   , a heat distribution bridge  112  extending a predetermined length upwards from the lower surface thereof, and having the horizontal cross section of a cross (+) shape may be further formed on the inner surface of the heat distribution space  111 . Preferably, the heat distribution bridge  112  may be formed to extend upwards from the lower surface of the heat distribution space  111  to the intermediate portion thereof. 
     The heat distribution bridge  112  quickly conducts the heat agglomerated in the heat distribution space  111  and the heat directly delivered from the lower end portion of the coupling body  110  to the upper side of the outer circumferential surface of the coupling body  110  provided with the plurality of horizontal heat-dissipation fins  130 . 
     Meanwhile, as illustrated in  FIGS.  3  to  5   , a plurality of air vent holes  113  for communicating the heat distribution space  111  with the outside may be formed in the coupling body  110 . 
     More specifically, the plurality of air vent holes  113  may be formed to be arranged in a straight line upwards from the inner wall surfaces of the four spaces partitioned by the heat distribution bridge  112  of the cross ‘+’ shape in the heat distribution space  111 , respectively. 
     Preferably, since the plurality of horizontal heat-dissipation fins  130  are vertically provided at the outside of the coupling body  110  as described above, it is preferable that the plurality of air vent holes  113  are formed to be penetrated between the plurality of horizontal heat-dissipation fins  130 . 
     The plurality of air vent holes  113  serve as having uniform heat-dissipation performance by discharging the heat aggregated in the heat distribution space  111  to the outside corresponding to each layer formed by the plurality of horizontal heat-dissipation fins  130 . That is, the plurality of air vent holes  113  may prevent the delivered heat from being agglomerated or eccentrically dissipated by smoothly circulating the air in the heat distribution space  111 . 
     Meanwhile, an element contact surface is formed to be protruded by a predetermined length toward the heat-generation element  51  on one surface (that is, the lower surface forming the lower end portion of the coupling body  110  in the figure) forming one end portion of the coupling body  110 . 
     As illustrated in  FIGS.  2  and  3   , the element contact surface may be formed to have the appearance of a shape corresponding to the upper surface of the heat-generation element that is substantially in contact, and may be preferably formed to have a shape capable of directly contacting the heat-generation element  51  provided on the lower portion thereof without interfering with the plurality of fastening flanges  15  formed in the through hole  13 . 
     The element contact surface may also be molded integrally with the coupling body  110  as the same material having the same thermal conductivity as the coupling body  110 , but may also be provided as a heat conductive medium block  125  to be described later. This will be described later in detail. 
     Meanwhile, a plurality of screw fastening holes  117  may be formed on the rim portion of the lower surface of the coupling body  110  corresponding to the remainder except for the element contact surface. The plurality of screw fastening holes  117  are preferably formed so that the fastening screw  114  is fastened from the lower side to the upper side in the figure. Although it has been limitedly described in a preferred embodiment of the present disclosure that the shape of the element contact surface described above is adopted as a square shape, and the plurality of screw fastening holes  117 , that is, four ones are formed by one at the outside of each surface of the element contact surface of the square shape, the present disclosure is not limited thereto. 
     Since the fastening screw  114  is provided to be fastened to the lower side in the figure, the coupling body  110  has one surface moved to the side at which the heat-generation element  51  has been provided upon the coupling with the coupling screw  114 . 
     The plurality of screw fastening holes  117  may move the coupling body  110  from the upper side to the lower side of the through hole  13  to match with a screw through hole  16  formed on the plurality of fastening flanges  15  and then screw-couple it by using the fastening screw  114  to primarily fix the coupling body  110  to the heat-dissipation part housing  11 . 
     However, a predetermined assembling tolerance necessary for coupling the coupling body  110  to the through hole  13  of the heat-dissipation part housing  11  should be considered upon the design of the product, while there is the possibility in which the height deviation, and the like occurs when mounting the heat-generation element  51  on one surface of the PCB  50  in a method such as the soldering method. 
     Here, the upper surface of the heat-generation element  51  and the lower surface of the coupling body  110  of the second heat-dissipation part  100  for directly dissipating the heat may implement optimum heat-dissipation performance only when they directly contact each other, but there is a problem in that a gap occurs or a direct contact coupling is not easy due to the above-described assembling tolerance, height deviation, and the like even after the coupling by the fastening screw  114  has been completed. 
     In order to solve such a problem, in a preferred embodiment of the MIMO antenna apparatus  1  according to the present disclosure, a tolerance absorption ring  115 , which closely contacts the plurality of fastening flanges  15  by the head portion  114   b  of the fastening screw  114 , respectively, upon the coupling of the fastening screw  114 , and is elastically deformed by the coupling force generated upon the coupling of the PCB  50  to the heat-dissipation part housing  11 , may be interposed on the outer circumferential surface of the fastening screw  114 . 
     More specifically, the fastening screw  114  is composed of a body  114   a  having a male thread formed thereon, and the head portion  114   b  formed at the front end of the body  114   a  and having a tool groove of a cross (+) or a straight (−) shape, into which a fastening tool such as a driver is fitted, formed thereon. 
     Here, the tolerance absorption ring  115  is fitted to the outer circumferential surface of the body  114   a , the upper end of the tolerance absorption ring  115  upon the coupling of the fastening screw  114  to the plurality of fastening flanges  15  is supported by the inner surface of the fastening groove  17  of the fastening flange  15  in which the head portion  114   b  is accommodated and the lower end of the tolerance absorption ring  115  is supported by the head portion  114   b.    
     The tolerance absorption ring  115  thus coupled maintains the state elastically deformed by the coupling force of the fastening member in a state where the upper surface of the heat-generation element  51  and the element contact surface of the coupling body  110  have contacted when coupling the PCB  50 , on which the heat-generation element  51  has been mounted, to the inside surface of the PCB accommodation space  5  by using a fastening member not illustrated. 
     Then, even after the coupling of the PCB  50  has been completed by the permanent restoring force of the tolerance absorption ring  115 , a mutual forcibly pressing force is formed between the element contact surface of the coupling body  110  and the upper surface of the heat-generation element  51 . Here, the permanent restoring force of the tolerance absorption ring  115  refers to an inherent force that restores the deformed shape again due to the material characteristics if the external force is removed after a shape has been deformed if an external force is provided because its material is an elastic material such as rubber. 
     Formation of such a forcibly pressing force may prevent the mutual separation phenomenon between the element contact surface of the coupling body  110  and the upper surface of the heat-generation element  51 , thereby greatly enhancing heat-dissipation performance. 
     Further, since the precise design of the product according to the assembling tolerance, the height deviation, and the like is not required, it is possible to enhance universality of the product. 
     However, the coupling body  110  is not necessarily coupled in such a manner as to be coupled to the through hole  13  of the heat-dissipation part housing  11  by the fastening screw  114  as described above. 
     That is, referring to the left side in the figure of  FIG.  2   , a male thread is formed on the outer circumferential surface of the lower end portion of the coupling body  110 , and a female thread corresponding to the male thread may be processed and formed on the inner circumferential surface of the through hole  13  so that the coupling body  110  is screw-coupled. 
     However, in this case, the fastening flange  15  that may eliminate the assembling tolerance, the height deviation, and the like, instead of the easy coupling of the second heat-dissipation part  100  to the first heat-dissipation part  10 , is not provided in the through hole  13 , thereby degrading heat-dissipation performance and universality, but this may be eliminated by a locking ring  120  and a sealing member  119  to be described later. 
     More specifically, as illustrated in  FIGS.  3  to  5   , a sealing installation groove  118  is formed to have a groove shape on the outer circumferential surface of the coupling body  110  corresponding to the lower portion of the plurality of horizontal heat-dissipation fins  130 , and a sealing member  119  is interposed in the sealing installation groove  118 . 
     The sealing member  119  serves as blocking a gap between the inner circumferential surface of the upper end portion of the guide boss  14  and the outer circumferential surface of the coupling body  110  upon the coupling of the coupling body  110  to the through hole  13 . 
     Meanwhile, the locking ring  120  is screw-coupled to the outer circumferential surface of the coupling body  110  corresponding to the upper portion of the sealing installation groove  118 . To this end, a female thread  120   a  may be formed on the inner circumferential surface of the locking ring  120 , and a male thread  120   b  may be formed on a corresponding portion where the locking ring  120  is installed in the outer circumferential surface of the coupling body  110 . 
     The outer circumferential surface of the locking ring  120  is preferably formed to have a horizontal cross section of a polygonal shape so that an assembler may rotate by using an assembly tool such as a spanner. 
     The locking ring  120  is rotatably assembled so that the lower end of the locking ring  120  closely contacts the upper end of the guide boss  14  by using the assembly tool such as the above-described spanner, after the lower end portion of the coupling body  110  has been coupled to the fastening flange  15  of the through hole  13  in a state pre-coupled to the outer circumferential surface of the coupling body  110  with the margin in advance. 
     At this time, the coupling body  110  may be coupled to be supported by the fastening flange  15  primarily by the fastening screw  114  on the lower side of the through-hole  13 , and coupled to be supported by the front end of the guide boss  14  secondarily by the locking ring  120  at the upper side of the through hole  13 , thereby being firmly fixed to the first heat-dissipation part  10 . 
     Further, when the lower end of the locking ring  120  is rotatably coupled to closely contact the front end of the guide boss  14 , it may press the sealing member  119 , thereby performing the same function as that of the above-described tolerance absorption ring  115  while the sealing member  119  is elastically deformed. 
     For example, regardless of the coupling method of the coupling body  110  to the through hole  13 , once the sealing member  119  is elastically deformed by rotatably adjusting the locking ring  120  in a state where the element contact surface of the coupling body  110  has contacted the upper surface of the heat-generation element  51  of the PCB  50 , the forcibly pressing force such as the tolerance absorption ring  115  is continuously formed between the element contact surface of the coupling body  110  and the upper surface of the heat-generation element  51  by the sealing member  119 . 
     Accordingly, the sealing member  119  performs the sealing function of blocking the inflow of foreign substances such as moisture in a direction in which the PCB  50  has been provided through the through hole  13  from the outside while performing the same function as that of the tolerance absorption ring  115 . 
     Meanwhile, in a preferred embodiment of the MIMO antenna apparatus  1  according to the present disclosure, as illustrated in  FIG.  4   , the second heat-dissipation part  100  may further include the heat conductive medium block  125  coupled to one surface (the lower surface) of the coupling body  110 , and contacting one surface (the upper surface) of the heat-generation element  51 . 
     The heat conductive medium block  125  is preferably made of a material having a higher thermal conductivity than that of the coupling body  110 . That is, the element contact surface of the coupling body  110  may be replaced with the heat conductive medium block  125  having a high thermal conductivity. 
     In a preferred embodiment of the MIMO antenna apparatus  1  according to the present disclosure, the thermal conductivity of the coupling body  110  is provided to have its own heat-dissipation performance, but a preferred embodiment may allow the lower surface of the heat conductive medium block  125  having a higher thermal conductivity than the thermal conductivity of the coupling body  110  to serve as the element contact surface, thereby further enhancing heat-dissipation performance. 
     Here, the heat conductive medium block  125  may be coupled to the coupling groove formed in the groove shape on the lower surface of the coupling body  110  by any one method of a screw coupling method and a forcibly press-fitting method. 
     However, the method in which the coupling body  110  of the heat conductive medium block  125  is provided is not limited to the above-described methods. That is, the heat conductive medium block  125  may be coupled to the lower surface of the coupling body  110  in any one method of a bonding coupling method, a brazing coupling method, and a heterogeneous injection molding method so that the lower surface of the heat conductive medium block  125  is exposed. 
     Further, a thermally conductive medium material may be applied to the element contact surface, which is the lower surface of the coupling body  110  contacting the heat-generation element  51  or the lower surface of the heat conductive medium block  125 . 
     The thermally conductive medium material is preferably applied to the element contact surface or the lower surface of the heat conductive medium block  125  in the sprayed form. 
       FIG.  6    is a perspective diagram illustrating an air baffle in the configuration in  FIG.  1   , and  FIGS.  7 A to  7 C  are perspective diagrams illustrating various forms of the second heat-dissipation part in the configuration of the MIMO antenna apparatus according to the present disclosure. 
     As illustrated in  FIG.  6   , a preferred embodiment of the MIMO antenna apparatus  1  according to the present disclosure may include an air baffle  200  disposed to partition between two second heat-dissipation parts  100  if at least two second heat dissipating parts  100  are disposed at the upper side and the lower side by one or by one or more, respectively, on one surface of the heat-dissipation part housing  11  disposed vertically. 
     As illustrated in  FIG.  4   , since the air baffle  200  may implement the non-uniform heat-dissipation performance for each second heat-dissipation part  100  if the heat dissipated by the second heat-dissipation parts  100 A,  100 B provided at the lower side relatively is delivered by the rising airflow to the second heat-dissipation part  100  provided at the upper side relatively according to the natural convection, the air baffle  200  serves as blocking the rising airflow of the lower side, thereby implementing overall uniform heat-dissipation performance. 
     The air baffle  200  may be provided to have the front end portion inclined upwards and accordingly, provided so that the heat dissipated from the horizontal heat-dissipation fin  130  of the second heat-dissipation part  100  of the lower side bypasses the second heat-dissipation part  100  of the upper side to be moved upwards without being stagnated by the air baffle  200 . 
     Meanwhile, the plurality of horizontal heat-dissipation fins  130  formed on the second heat-dissipation part  100  are arranged in multiple stages to be spaced at a predetermined distance apart from each other from the heat-generation element  51  to the outside (that is, the upper side in the figure of  FIGS.  7 A to  7 C ). 
     Here, the appearance combination of the plurality of horizontal heat-dissipation fins  130  may be formed to have a cylindrical shape with a diameter of each horizontal heat-dissipation fin  130  having a horizontal cross-sectional shape of the same circular shape as illustrated in  FIGS.  1  to  6   , a hexahedral shape with each horizontal heat-dissipation fin  130  having an area of the horizontal cross section of the same square as illustrated in  FIG.  7 A , a sphere shape having the circular horizontal cross section shape, having the largest diameter of the intermediate portion, and having a smaller area gradually upwards or downwards as illustrated in  FIG.  7 B , and a cone shape having the circular horizontal cross section shape and having a smaller area gradually upwards as illustrated in  FIG.  7 C . 
     Here, the hexahedral shape illustrated in  FIG.  7 A  has a relatively simple structure and is easy to manufacture compared to the cylindrical shape illustrated in  FIGS.  1  to  6   . Further, in the case of the shape illustrated in  FIG.  7 C , since the heat-dissipation area of the horizontal heat-dissipation fin of the lower side, which is the most important for heat dissipation, should be wide, it is possible to have the wide effective heat-dissipation area of the horizontal heat-dissipation fin of the lowermost side, and to reduce the area of the horizontal heat-dissipation fin upwards, thereby reducing the overall weight. 
     Further, referring to  FIGS.  7 A to  7 C , although only the embodiment in which the plurality of horizontal heat-dissipation fins  130  are stacked and disposed in 6 vertically to be spaced at a predetermined distance apart from each other are disclosed, the present disclosure is not necessarily limited thereto, and the number of the horizontal heat-dissipation fins  130  may be preferably designed differently considering the amount of heat generated by the heat-generation element  51 , the interference relationship with the peripheral component, and the like. 
     Further, it is natural that the horizontal area of the plurality of horizontal heat-dissipation fins  130  may also be actively changed in design considering the amount of heat generated by the heat-generation element  51 . 
     Comparing the operational relationship between the heat dissipation using the MIMO antenna apparatus  1  according to the present disclosure configured as described above and the heat dissipation according to the conventional method is as follows. 
       FIGS.  8 A and  8 B  are heat distribution diagrams for comparing the heat-dissipation performance of the conventional heat-dissipation mechanism and the MIMO antenna apparatus  1  according to the present disclosure. 
     The applicant of the present disclosure adopted the first heat-dissipation part  10  having the following common specification so that a common environment is constructed in order to obtain the most objective comparison data. 
     That is, the area of one surface of the heat-dissipation part housing  11  of the first heat-dissipation part  10  was 500×200×81 mm, the thickness of the heat-dissipation part housing  11  except for the plurality of vertical heat-dissipation fins  12  was 5.0 mm, the height of the plurality of the vertical heat-dissipation fins  12  was 60 mm, and the number of the plurality of vertical heat-dissipation fins  12  was 12 in common. 
     Further, the second heat-dissipation part  100  was vertically disposed in the first heat-dissipation part  10  so that two heat sources are vertically disposed to be spaced at a predetermined distance apart from each other vertically, and the cooling method applied a Natural Convection Cooling Type in which forced air is not involved at all. 
     As a result of performing the experiment under the same conditions as described above, as illustrated in  FIG.  8 A , upon the heat dissipation by the conventional method, the highest temperature of a first heat source  51   a  positioned at the upper side of the heat-generation elements  51  reached 87.5° C., while the highest temperature of a second heat source  51   b  positioned at the lower side of the heat-generation element  51  also reached 86.3° C., but it was confirmed that as illustrated in  FIG.  8 B , upon the heat dissipation through the MIMO antenna apparatus  1  according to a preferred embodiment of the present disclosure, the highest temperature of the first heat source  51   a  positioned at the upper side of the heat-generation element  51  was reduced to 83.6° C., while the highest temperature of the second heat source positioned at the lower side of the heat-generation element  51  was also reduced to 83.1° C. 
     That is, a preferred embodiment of the MIMO antenna apparatus  1  according to the present disclosure derived the temperature improvement effect of 3.8° C. based on the first heat source  51   a , and it was confirmed that in order to overcome the temperature difference through the conventional method, the height of the plurality of vertical heat-dissipation fins  12  should be further increased by 60 mm, which disproves that miniaturization of the product size is immediately possible. 
     Further, it was confirmed that according to the conventional method, the temperature deviation for each of the first heat source  51   a  and the second heat source  51   b  is 1.2° C., but upon the application of the MIMO antenna apparatus  1  according to a preferred embodiment of the present disclosure, since the temperature deviation is only 0.5°, it is possible to reduce the heat-dissipation performance for each heat source by the air baffle  200 , thereby implementing better heat-dissipation performance. 
     Accordingly, according to a preferred embodiment of the MIMO antenna apparatus  1  according to the present disclosure that is provided so that the lower surface of the coupling body  110  directly contacts the upper surface of the heat-generation element  51 , it is possible to implement excellent heat-dissipation performance compared to the conventional method attempting the heat dissipation through the medium configuration such as a thermal pad. 
     As described above, a preferred embodiment of the MIMO antenna apparatus according to the present disclosure has been described in detail with reference to the accompanying drawings. However, the embodiment of the present disclosure is not necessarily limited to the above-described preferred embodiment, and it is natural that various modifications and equivalents thereof may be made by those skilled in the art to which the present disclosure pertains. Accordingly, the true scope of the present disclosure will be determined by the claims to be described later. 
     INDUSTRIAL APPLICABILITY 
     According to the present disclosure, it is possible to manufacture the MIMO antenna apparatus, which may directly contact the heat-dissipation part to the heat-generation elements to significantly reduce the contact thermal resistance generated during the heat delivery, thereby enhancing heat-dissipation performance and increasing the apparatus lifespan, and to eliminate the assembling tolerance and the height deviation with the peripheral component, thereby enhancing universality.