Patent Publication Number: US-11658419-B2

Title: Antenna formed on flexible dielectric laminated body

Description:
TECHNICAL FIELD 
     The present disclosure relates to an antenna. 
     In recent years, widening and increasing a use frequency of a transmission signal are rapidly advancing due to a sudden increase in communication capacity in a wireless manner. In this way, a use frequency is being expanded from a band of a microwave at a frequency of 0.3 to 30 GHz to a band of a millimeter wave at a frequency of 30 to 300 GHz. In a 60 GHz band, attenuation of a transmission signal in the atmosphere is great, but there are advantages as follows. As a first advantage, communication data is less likely to leak. As a second advantage, many communication cells can be arranged by reducing the communication cell size. As a third advantage, a communication band is wide, and thus large-capacity communication can be performed. For these advantages, the 60 GHz band receives attention. However, due to great attenuation of a transmission signal, thus an antenna having high directivity, a high gain, and a wide band is desired. Particularly, research on an array antenna including a plurality of radiation elements aligned at a short pitch is eagerly performed. 
     Patent Literature 1 discloses an antenna in which a dielectric layer is bonded to a conductive ground layer, a plurality of radiation elements and microstrip feed lines are formed, and a spatial impedance conversion dielectric layer covers the radiation elements and the microstrip feed lines. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP H6-29723A 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     A dielectric layer needs to be sufficiently thin with respect to a wavelength in order to transmit a signal wave by a microstrip feed line. Since a thin dielectric layer is flexible, bending deformation in the dielectric layer also causes bending deformation in a radiation element, and radiation characteristics of the radiation element change. Further, a thin dielectric layer narrows a band of an antenna. 
     Thus, the present disclosure has been made in view of the circumstances described above. An objective of the present disclosure is to stabilize radiation characteristics of a radiation element by suppressing bending deformation of the radiation element, and to widen a band of an antenna. 
     Solution to Problem 
     A main aspect of the disclosure to achieve the above objective is an antenna comprising: a dielectric laminated body including a plurality of dielectric layers being laminated; a dielectric substrate bonded to one of surfaces of the dielectric laminated body; and a radiation element pattern layer, a conductive ground layer, and a conductive pattern layer each formed in a different place in any of both the surfaces and between the dielectric layers of the dielectric laminated body, wherein the radiation element pattern layer, the conductive ground layer, and the conductive pattern layer are formed in an order of the radiation element pattern layer, the conductive ground layer, and the conductive pattern layer from a dielectric substrate side toward an opposite side, and the radiation element pattern layer includes one or more radiation elements, the conductive pattern layer includes a feed line configured to feed power to the radiation elements, the dielectric laminated body is flexible, and the dielectric substrate is rigid. 
     Other features of the disclosure are made clear by the following description and the drawings. 
     Advantageous Effects of Invention 
     With the present disclosure, it is possible to suppress bending deformation of a radiation element, and radiation characteristics of the radiation element are stabilized and are less likely to change. 
     It is possible to suppress a radiation loss in a feed line and the radiation element by making each dielectric layer of a dielectric laminated body thin, and make a line width thin and achieve high-density wiring. Meanwhile, narrowing a band of an antenna is suppressed by arranging a dielectric substrate on the radiation element. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a cross-sectional view of an antenna according to a first embodiment. 
         FIG.  2    is a plan view of an antenna according to a second embodiment. 
         FIG.  3    is a cross-sectional view illustrating a cut place taken along III-III in  FIG.  2   . 
         FIG.  4    is a graph illustrating a simulation result of a gain of the antenna according to the second embodiment. 
         FIG.  5    is a graph illustrating a simulation result of a gain of the antenna according to the second embodiment. 
         FIG.  6    is a plan view of an antenna according to a first modified example of the second embodiment. 
         FIG.  7    is a plan view of an antenna according to a second modified example of the second embodiment. 
         FIG.  8    is a plan view of an antenna according to a third modified example of the second embodiment. 
         FIG.  9    is a plan view of an antenna according to a fourth modified example of the second embodiment. 
         FIG.  10    is a plan view of an antenna according to a fifth modified example of the second embodiment. 
         FIG.  11    is a plan view of an antenna according to a sixth modified example of the second embodiment. 
         FIG.  12    is a plan view of an antenna according to a third embodiment. 
         FIG.  13    is a cross-sectional view illustrating a cut place taken along XI-XI in  FIG.  12   . 
         FIG.  14    is a plan view of an antenna according to a first modified example of the third embodiment. 
         FIG.  15    is a plan view of an antenna according to a second modified example of the third embodiment. 
         FIG.  16    is a plan view of an antenna according to a third modified example of the third embodiment. 
         FIG.  17    is a plan view of an antenna according to a fourth modified example of the third embodiment. 
         FIG.  18    is a plan view of an antenna according to a fifth modified example of the third embodiment. 
         FIG.  19    is a plan view of an antenna according to a sixth modified example of the third embodiment. 
         FIG.  20    is a graph illustrating a simulation result of a reflection coefficient of the antenna according to the second embodiment. 
         FIG.  21    is a graph illustrating a simulation result of a gain of the antenna according to the second embodiment. 
         FIG.  22    is a graph illustrating a simulation result of a gain of the antenna according to the second embodiment. 
         FIG.  23    is a graph illustrating a simulation result of a reflection coefficient of the antenna according to the second embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     At least the following matters are made clear from the following description and the drawings. 
     An antenna will become clear comprising: a dielectric laminated body including a plurality of dielectric layers being laminated; a dielectric substrate bonded to one of surfaces of the dielectric laminated body; and a radiation element pattern layer, a conductive ground layer, and a conductive pattern layer each formed in a different place in any of both the surfaces and between the dielectric layers of the dielectric laminated body, wherein the radiation element pattern layer, the conductive ground layer, and the conductive pattern layer are formed in an order of the radiation element pattern layer, the conductive ground layer, and the conductive pattern layer from a dielectric substrate side toward an opposite side, and the radiation element pattern layer includes one or more radiation elements, the conductive pattern layer includes a feed line configured to feed power to the radiation elements, the dielectric laminated body is flexible, and the dielectric substrate is rigid. 
     As described above, even when the dielectric laminated body is flexible, the dielectric substrate is rigid, and thus it is possible to suppress bending deformation of the radiation element. Thus, radiation characteristics of the radiation element are stable and are less likely to change. 
     Since the dielectric substrate is rigid, the dielectric laminated body and each dielectric layer of the dielectric laminated body can be made thin. It is possible to suppress a radiation loss of a signal wave in the feed line by making a layer between the conductive pattern layer and the conductive ground layer thin. A quality factor of the antenna is low and a band is wide due to the dielectric substrate on the radiation element. Even when a layer between the conductive ground layer and the radiation element pattern layer is thin, narrowing of a band of the antenna is suppressed. 
     The antenna further comprising a parasitic element pattern layer formed on a surface of the dielectric laminated body located between the dielectric substrate and the radiation element pattern layer, or formed between layers of the dielectric laminated body located between the dielectric substrate and the radiation element pattern layer, wherein the parasitic element pattern layer includes a parasitic element in at least one position facing the radiation element. Preferably, a central part of the parasitic element overlaps a central part of the radiation element in a plan view, and a length of the parasitic element in a polarization direction is shorter than a length of the radiation element in the polarization direction. More preferably, a length of the parasitic element in the polarization direction is 70 to 95% of a length of the radiation element in the polarization direction. 
     In this way, the parasitic element faces the radiation element, and thus the antenna has a wider band. 
     The antenna further comprising an adhesive layer of a dielectric configured to adhere the dielectric laminated body and the dielectric substrate, wherein the parasitic element is formed on a surface of the dielectric laminated body in the adhesive layer, and the adhesive layer is thicker than the parasitic element and is thinner than the dielectric substrate. 
     In this way, a void is less likely to be generated around the parasitic element at a bonding interface between the adhesive layer and the dielectric laminated body. The adhesive layer does not greatly affect radiation characteristics of the radiation element and the parasitic element as compared to the dielectric substrate. 
     The antenna further comprising a parasitic element pattern layer formed between layers of the dielectric laminated body between the radiation element pattern layer and the conductive ground layer, wherein the parasitic element pattern layer includes a parasitic element in at least one position facing the radiation element. Preferably, a central part of the parasitic element overlaps a central part of the radiation element in a plan view, and a length of the radiation element in a polarization direction is shorter than a length of the parasitic element in the polarization direction. 
     In this way, the parasitic element faces the radiation element, and thus the antenna has a wider band. 
     The antenna further comprising an adhesive layer of a dielectric configured to adhere the dielectric laminated body and the dielectric substrate, wherein the radiation element is formed on a surface of the dielectric laminated body in the adhesive layer, and the adhesive layer is thicker than the radiation element and is thinner than the dielectric substrate. 
     In this way, a void is less likely to be generated around the radiation element at a bonding interface between the adhesive layer and the dielectric laminated body. The adhesive layer does not greatly affect radiation characteristics of the radiation element and the parasitic element as compared to the dielectric substrate. 
     A thickness of the dielectric substrate is 300 to 700 μm. 
     In this way, directivity in a normal direction of a surface of the dielectric substrate is high, and a gain in the normal direction is high. 
     A thickness of the dielectric laminated body is equal to or less than 300 μm. 
     Four, six, or eight of the radiation elements are linearly aligned at intervals and connected in series, and the feed line feeds power to the center of a row of the radiation elements. 
     In this way, an improvement in gain of the antenna can be achieved. 
     The antenna wherein two rows of the radiation elements are linearly arranged in line, and one of the radiation element rows has a shape that is line symmetric or point symmetric with a shape of another of the radiation element rows, or has a shape obtained by translating the another radiation element row. 
     In this way, an improvement in gain of the antenna can be achieved. 
     A plurality of the radiation element rows are aligned at a predetermined pitch in a direction orthogonal to a direction of the radiation element rows, and radiation elements positioned in the same order in the radiation element rows are aligned in line in the orthogonal direction. 
     In this way, an improvement in gain of the antenna can be achieved. 
     The predetermined pitch is 0.4 to 0.6 times a wavelength at the highest frequency to be used. 
     A plurality of groups each including a plurality of the radiation element rows aligned at the predetermined pitch in the direction orthogonal to the direction of the radiation element rows are located, and row directions of the radiation element rows in all of the groups are parallel to each other. 
     Embodiments 
     Embodiments of the disclosure are described below with reference to the drawings. Note that, although various limitations that are technically preferable for carrying out the disclosure are imposed on the embodiments to be described below, the scope of the disclosure is not to be limited to the embodiments below and illustrated examples. 
     First Embodiment 
       FIG.  1    is a cross-sectional view of an antenna  1  according to a first embodiment. The antenna  1  is used for transmitting, receiving, or both transmitting and receiving a radio wave in a frequency band of a microwave or a millimeter wave. 
     A protective dielectric layer  11 , a dielectric layer  12 , a dielectric layer  13 , a dielectric layer  14 , a dielectric layer  15 , and a dielectric layer  16  are laminated in this order, and a dielectric laminated body  10  formed of the dielectric layers  11  to  16  is thus formed. All of the dielectric layers  11  to  16  are flexible, and the dielectric laminated body  10  is also flexible. 
     An adhesive layer  19  formed of a dielectric adhesive material is sandwiched between the dielectric laminated body  10  and a dielectric substrate  31 , and more specifically, between the dielectric layer  16  and the dielectric substrate  31 . The dielectric layer  16  and the dielectric substrate  31  are bonded to each other with the adhesive layer  19 . Note that the adhesive layer  19  may not be provided, and the dielectric layer  16  and the dielectric substrate  31  may be directly bonded to each other. 
     The dielectric substrate  31  is formed of a fiber reinforced resin, and more specifically, a glass fiber reinforced epoxy resin, a glass-cloth base material epoxy resin, a glass-cloth base material polyphenylene ether resin, or the like. The dielectric substrate  31  is rigid. 
     The dielectric layer  12 , the dielectric layer  14 , and the dielectric layer  16  are formed of a liquid crystal polymer. 
     The dielectric layer  13  is formed of an adhesive material, and the dielectric layer  12  and the dielectric layer  14  are bonded to each other with the dielectric layer  13  sandwiched therebetween. The dielectric layer  15  is formed of an adhesive material, and the dielectric layer  14  and the dielectric layer  16  are bonded to each other with the dielectric layer  15  sandwiched therebetween. The protective dielectric layer  11  is formed on a surface of the dielectric layer  12  on a side opposite to the dielectric layer  13  with respect to the dielectric layer  12 . 
     A conductive pattern layer  21  is formed between the protective dielectric layer  11  and the dielectric layer  12 . The protective dielectric layer  11  is formed on the surface of the dielectric layer  12  so as to cover the conductive pattern layer  21 . In this way, the conductive pattern layer  21  is protected. Note that the conductive pattern layer  21  may be exposed by not forming the protective dielectric layer  11 . 
     A conductive ground layer  22  is formed between the dielectric layer  12  and the dielectric layer  13 . The dielectric layer  13  covers the conductive ground layer  22  and is bonded to the conductive ground layer  22 , and is also bonded to the dielectric layer  12  in a portion (for example, a hole, a slot, a slit, or the like) where the conductive ground layer  22  is not provided. 
     A radiation element pattern layer  23  is formed between the dielectric layer  14  and the dielectric layer  15 . The dielectric layer  15  covers the radiation element pattern layer  23  and is bonded to the radiation element pattern layer  23 , and is also bonded to the dielectric layer  14  in a portion where the radiation element pattern layer  23  is not provided. 
     A parasitic element pattern layer  24  is formed between the dielectric layer  16  and the adhesive layer  19 . The adhesive layer  19  covers the parasitic element pattern layer  24  and is bonded to the parasitic element pattern layer  24 , and is also bonded to the dielectric layer  16  in a portion where the parasitic element pattern layer  24  is not provided. 
     Note that, in the example illustrated in  FIG.  1   , the parasitic element pattern layer  24  is formed on a surface of the dielectric laminated body  10 . In contrast, the dielectric laminated body  10  may be a laminated body of more dielectric layers, and the parasitic element pattern layer  24  may be formed between the layers of the dielectric laminated body  10 . 
     The conductive pattern layer  21 , the conductive ground layer  22 , the radiation element pattern layer  23 , and the parasitic element pattern layer  24  are formed of a conductive metal material such as copper. 
     The radiation element pattern layer  23  is shape-processed by an additive method, a subtractive method, or the like, and thus a radiation element  23   a  having a patch shape is formed on the radiation element pattern layer  23 . 
     The parasitic element pattern layer  24  is shape-processed by an additive method, a subtractive method, or the like, and thus a parasitic element  24   a  having a patch shape is formed on the parasitic element pattern layer  24 . The parasitic element  24   a  is located so as to overlap the radiation element  23   a  in a plan view. In other words, the parasitic element  24   a  faces the radiation element  23   a . Here, the plan view refers to viewing a target such as the antenna  1  from above or below the target in a direction of arrows A or B in a parallel projection manner. The directions of the arrows A and B are a laminated direction of the antenna  1 , i.e., a direction perpendicular to a surface of the protective dielectric layer  11 , the dielectric layer  12 , the dielectric layer  13 , the dielectric layer  14 , the dielectric layer  15 , the dielectric layer  16 , the adhesive layer  19 , or the dielectric substrate  31 . 
     The parasitic element  24   a  is smaller than the radiation element  23   a , and the entire parasitic element  24   a  is located inside an outer shape of the radiation element  23   a  in the plan view. In other words, a central part of the parasitic element  24   a  overlaps a central part of the radiation element  23   a  in the plan view. The reason is that, if the parasitic element  24   a  is larger than the radiation element  23   a , a radiation gain decreases at a high frequency. 
     The parasitic element  24   a  and the radiation element  23   a  are different from each other in size, and thus different from each other in a resonant frequency. In other words, the antenna  1  has frequency characteristics such that a gain at a resonant frequency of the radiation element  23   a  and a resonant frequency of the parasitic element  24   a  takes a local maximum value. Thus, a use band of the antenna  1  is widened. 
     It is desirable that a length of the parasitic element  24   a  in a polarization direction is 70 to 95% of a length of the radiation element  23   a  in the polarization direction. The reason is that, even when a length of the parasitic element  24   a  in the polarization direction exceeds 95% of a length of the radiation element  23   a  in the polarization direction, a use band of the antenna  1  is not much widened. Further, the reason is that widening of a use band of the antenna  1  when a length of the parasitic element  24   a  in the polarization direction is less than 70% of a length of the radiation element  23   a  in the polarization direction is about the same as widening of a use band of the antenna  1  when a length of the parasitic element  24   a  in the polarization direction is 70% of a length of the radiation element  23   a  in the polarization direction. 
     Particularly, when a length of the parasitic element  24   a  in the polarization direction is 80 to 95% of a length of the radiation element  23   a  in the polarization direction, reflection in a use band of the antenna  1  is easily suppressed. Furthermore, when a length of the parasitic element  24   a  in the polarization direction is 85 to 90% of a length of the radiation element  23   a  in the polarization direction, reflection in a use band of the antenna  1  is more easily suppressed. 
     In a case of a low frequency, the parasitic element  24   a  functions as a wave director that resonates a radio wave at a predetermined frequency transmitted and received by the radiation element  23   a , and thus enhances directivity of the radio wave in a perpendicular line. 
     In a case of a high frequency, the radiation element  23   a  functions as a driven element, and the parasitic element  24   a  functions as a radiation element that resonates a radio wave at a predetermined frequency by power feed to the radiation element  23   a  and radiates the radio wave. 
     The adhesive layer  19  is thicker than the parasitic element  24   a . Thus, a void is less likely to be generated around the parasitic element  24   a  at a bonding interface between the adhesive layer  19  and the dielectric layer  16 . 
     The adhesive layer  19  is thinner than the dielectric substrate  31 , and particularly, a thickness of the adhesive layer  19  is equal to or less than 1/10 of a thickness of the dielectric substrate  31 . Thus, the adhesive layer  19  does not greatly affect radiation characteristics of the parasitic element  24   a  and the radiation element  23   a  as compared to the dielectric substrate  31 . Note that, when a thickness of the dielectric substrate  31  is 300 to 700 μm and a thickness of the parasitic element  24   a  is about 12 μm, it is preferable that a thickness of the adhesive layer  19  is 15 to 50 μm. 
     The conductive ground layer  22  is shape-processed by an additive method, a subtractive method, or the like, and thus a slot  22   a  is formed in the conductive ground layer  22 . The slot  22   a  is located so as to overlap the central part of the radiation element  23   a  in the plan view. In other words, the slot  22   a  faces the central part of the radiation element  23   a.    
     The conductive pattern layer  21  is shape-processed by an additive method, a subtractive method, or the like, and thus the feed line  21   a  is formed on the conductive pattern layer  21 . The feed line  21   a  is a microstrip line wired from a terminal of a radio frequency integrated circuit (RFIC) to a counter position of the slot  22   a . One end part of the feed line  21   a  faces the slot  22   a , and the one end part is electrically connected to the radiation element  23   a  through a through hole conductor  25 . The other end part of the feed line  21   a  is connected to the terminal of the RFIC. Thus, power is fed from the RFIC to the radiation element  23   a  via the feed line  21   a  and the through hole conductor  25 . 
     The through hole conductor  25  penetrates the dielectric layer  12 , the conductive ground layer  22 , the dielectric layer  13 , and the dielectric layer  14 . At a place where the through hole conductor  25  penetrates the conductive ground layer  22 , the through hole conductor  25  is separated inward from an edge of the slot  22   a , and the through hole conductor  25  and the conductive ground layer  22  are electrically insulated from each other. The through hole conductor  25  is a conductor (for example, copper plating) that fills in a through hole, or a conductor (for example, copper plating) film-formed on an inner wall of a through hole. Note that the through hole conductor  25  may not be formed, and the one end part of the feed line  21   a  may be electromagnetically coupled to the radiation element  23   a  through the slot  22   a.    
     A thickness of the dielectric laminated body  10  (a sum total of thicknesses of the dielectric layers  12  to  16  when the protective dielectric layer  11  is not formed, and a sum total of thicknesses of the protective dielectric layer  11  and the dielectric layers  12  to  16  when the protective dielectric layer  11  is formed) is thinner than a thickness of the dielectric substrate  31 . Particularly, a thickness of the dielectric laminated body  10  is equal to or less than 300 μm. 
     Since a thickness of the dielectric substrate  31  falls within a range of 300 to 700 μm, a gain of the antenna  1  is high and directivity into a normal direction of a surface of the dielectric substrate  31  is strong. 
     The protective dielectric layer  11  and the dielectric layers  12  to  16  are flexible, and the dielectric substrate is rigid. In other words, flex resistance of the protective dielectric layer  11  and the dielectric layers  12  to  16  is sufficiently higher than flex resistance of the dielectric substrate  31 , and a modulus of elasticity of the dielectric substrate  31  is sufficiently higher than a modulus of elasticity of the protective dielectric layer  11  and the dielectric layers  12  to  16 . Thus, bending of the antenna  1  is less likely to occur. Particularly, a change in radiation characteristics of the radiation element  23   a  and the parasitic element  24   a  due to bending deformation of the radiation element  23   a  and the parasitic element  24   a  is less likely to occur. 
     The dielectric layer  12  is thin, and has a low dielectric constant and a low dielectric loss tangent. Moreover, when the protective dielectric layer  11  is not formed, the feed line  21   a  is exposed to the air, and thus a transmission loss of a signal wave in the feed line  21   a  is low. Since an electric field is mainly formed between the radiation element  23   a  and the conductive ground layer  22 , and the dielectric layers  14  and  16  have a low dielectric constant and a low dielectric loss tangent, a loss in the radiation element  23   a  and the parasitic element  24   a  is low even when the radiation element  23   a  and the parasitic element  24   a  are covered with the dielectric substrate  31 . Meanwhile, the dielectric substrate  31  does not need to be made thin, and it is possible to suppress narrowing of the band of the antenna  1 . 
     When the dielectric substrate  31  is formed of a glass-cloth base material epoxy resin (particularly, FR4), a bending modulus of elasticity in a vertical direction is 24.3 GPa, a bending modulus of elasticity in a horizontal direction is 20.0 GPa, a dielectric constant is 4.6, and a dielectric loss tangent is 0.050. Here, the bending modulus of elasticity in the vertical direction and the horizontal direction is measured by a test method based on the standard of ASTM D 790, and the dielectric constant and the dielectric loss tangent are measured by a test method (frequency: 3 GHz) based on the standard of ASTM D 150. 
     When the dielectric substrate  31  is formed of a glass-cloth base material polyphenylene ether resin (particularly, Megtron (registered trademark) 6) made by Panasonic Corporation, a bending modulus of elasticity in the horizontal direction is 18 GPa, a relative dielectric constant (Dk) is 3.4, and a dielectric loss tangent (Df) is 0.0015. Here, the bending modulus of elasticity in the horizontal direction is measured by a test method based on the standard of JIS C 6481, and the relative dielectric constant and the dielectric loss tangent are measured by a test method (frequency: 1 GHz) based on the standard of IPC TM-650 2.5.5.9. 
     On the other hand, when the dielectric layers  12 ,  14 , and  16  are formed of a liquid crystal polymer, a bending modulus of elasticity is 12152 MPa, a dielectric constant is 3.56, and a dielectric loss tangent is 0.0068. Here, the bending modulus of elasticity is measured by a test method based on the standard of ASTM D 790, and the dielectric constant and the dielectric loss tangent are measured by a test method (frequency: 10 3  Hz) based on the standard of ASTM D 150. 
     Note that a multilayer wiring structure may be formed between the layers of the protective dielectric layer  11  and the dielectric layers  12  to  16  in a region in which the radiation element  23   a  and the parasitic element  24   a  are not formed. 
     Second Embodiment 
       FIG.  2    is a plan view of an antenna  101  according to a second embodiment.  FIG.  3    is a cross-sectional view taken along III-III in  FIG.  2   . The antenna  101  is used for transmitting, receiving, or both transmitting and receiving a radio wave in a frequency band of a microwave or a millimeter wave. 
     In a similar manner to the first embodiment in which the protective dielectric layer  11 , the conductive pattern layer  21 , the dielectric layer  12 , the conductive ground layer  22 , the dielectric layer  13 , the dielectric layer  14 , the radiation element pattern layer  23 , the dielectric layer  15 , the dielectric layer  16 , the parasitic element pattern layer  24 , the adhesive layer  19 , and the dielectric substrate  31  are laminated in this order, in the second embodiment a protective dielectric layer  111 , a conductive pattern layer  121 , a dielectric layer  112 , a conductive ground layer  122 , a dielectric layer  113 , a dielectric layer  114 , a radiation element pattern layer  123 , a dielectric layer  115 , a dielectric layer  116 , a parasitic element pattern layer  124 , an adhesive layer  119 , and a dielectric substrate  131  are laminated. 
     A composition and a thickness of the protective dielectric layer  111  are the same as a composition and a thickness of the protective dielectric layer  11  according to the first embodiment. A composition and a thickness of the conductive pattern layer  121  are the same as a composition and a thickness of the conductive pattern layer  21  according to the first embodiment. A composition and a thickness of the dielectric layer  112  are the same as a composition and a thickness of the dielectric layer  12  according to the first embodiment. A composition and a thickness of the conductive ground layer  122  are the same as a composition and a thickness of the conductive ground layer  22  according to the first embodiment. A composition and a thickness of the dielectric layer  113  are the same as a composition and a thickness of the dielectric layer  13  according to the first embodiment. A composition and a thickness of the dielectric layer  114  are the same as a composition and a thickness of the dielectric layer  14  according to the first embodiment. A composition and a thickness of the radiation element pattern layer  123  are the same as a composition and a thickness of the radiation element pattern layer  23  according to the first embodiment. A composition and a thickness of the dielectric layer  115  are the same as a composition and a thickness of the dielectric layer  15  according to the first embodiment. A composition and a thickness of the dielectric layer  116  are the same as a composition and a thickness of the dielectric layer  16  according to the first embodiment. A composition and a thickness of the parasitic element pattern layer  124  are the same as a composition and a thickness of the parasitic element pattern layer  24  according to the first embodiment. A composition and a thickness of the adhesive layer  119  are the same as a composition and a thickness of the adhesive layer  19  according to the first embodiment. A composition and a thickness of the dielectric substrate  131  are the same as a composition and a thickness of the dielectric substrate  31  according to the first embodiment. 
     Note that the adhesive layer  119  may not be provided, and the dielectric layer  116  and the dielectric substrate  131  may be directly bonded to each other. The conductive pattern layer  121  may be exposed by not forming the protective dielectric layer  111 . 
     The protective dielectric layer  111  and the dielectric layers  112  to  116  are flexible, and a dielectric laminated body  110  formed of the protective dielectric layer  111  and the dielectric layers  112  to  116  is flexible. The dielectric substrate  131  is rigid. 
     The radiation element pattern layer  123  is shape-processed by an additive method, a subtractive method, or the like, and thus an element row  123   a  is formed on the radiation element pattern layer  123 . The element row  123   a  includes radiation elements  123   b  to  123   e  having a patch shape, feed lines  123   f ,  123   g ,  123   i , and  123   j , and a land part  123   h.    
     The radiation elements  123   b  to  123   e  are linearly aligned in this order in one row at intervals. Here, it is assumed that the radiation element  123   b  is leading, and the radiation element  123   e  is rearmost in the element row  123   a.    
     The radiation elements  123   b  to  123   e  are connected in series as follows. 
     The leading radiation element  123   b  and the second radiation element  123   c  are connected in series with the feed line  123   f  provided therebetween. The land part  123   h  is provided at the center of the element row  123   a , i.e., between the second radiation element  123   c  and the third radiation element  123   d . The second radiation element  123   c  and the land part  123   h  are connected in series with the feed line  123   g  provided therebetween. The third radiation element  123   d  and the land part  123   h  are connected in series with the feed line  123   i  provided therebetween. The third radiation element  123   d  and the rearmost radiation element  123   e  are connected in series with the feed line  123   j  provided therebetween. The feed lines  123   f ,  123   g , and  123   j  are linearly formed, and the feed line  123   i  is bent. A length of the feed line  123   g  is shorter than a length of the feed lines  123   f ,  123   i , and  123   j.    
     Since the element row  123   a  includes the four radiation elements  123   b  to  123   e , a gain of the antenna  101  is high. 
     The parasitic element pattern layer  124  is shape-processed by an additive method, a subtractive method, or the like, and thus parasitic elements  124   b  to  124   e  having a patch shape are formed on the parasitic element pattern layer  124 . In the plan view, the parasitic element  124   b , the parasitic element  124   c , the parasitic element  124   d , and the parasitic element  124   e  are located so as to overlap the radiation element  123   b , the radiation element  123   c , the radiation element  123   d , and the radiation element  123   e , respectively. In other words, the parasitic elements  124   b  to  124   e  face the radiation elements  123   b  to  123   e , respectively. 
     The parasitic element  124   b  has a length in the polarization direction shorter than that of the radiation element  123   b , and a side of the parasitic element  124   b  in a direction perpendicular to polarization is located inside a side of the radiation element  123   b  in the direction perpendicular to polarization in the plan view. The reason is that, if the parasitic element  124   b  is larger than the radiation element  123   b , a radiation gain decreases at a high frequency. Similarly, a side of the parasitic element  124   c  in the direction perpendicular to polarization is located inside a side of the radiation element  123   c  in the direction perpendicular to polarization in the plan view. 
     A length of the parasitic elements  124   b  to  124   e  in the polarization direction is 70 to 95% of a length of the radiation elements  123   b  to  123   e  in the polarization direction, is preferably 80 to 95% of a length of the radiation elements  123   b  to  123   e  in the polarization direction, and is more preferably 85 to 90% of a length of the radiation elements  123   b  to  123   e  in the polarization direction. 
     The parasitic elements  124   b  to  124   e  and the radiation elements  123   b  to  123   e  are different from each other in size, and thus different from each other in a resonant frequency. In other words, the antenna  101  has frequency characteristics such that a gain at a resonant frequency of the radiation elements  123   b  to  123   e  and a resonant frequency of the parasitic elements  124   b  to  124   e  takes a local maximum value. Thus, a use band of the antenna  101  is widened. 
     In a case of a low frequency, the parasitic elements  124   b  to  124   e  function as a wave director that resonates a radio wave at a predetermined frequency transmitted and received by each of the radiation elements  123   b  to  123   e , and thus enhances directivity of a radio wave in a perpendicular direction. 
     In a case of a high frequency, the radiation elements  123   b  to  123   e  function as driven elements, and the parasitic elements  124   b  to  124   e  function as radiation elements that resonate a radio wave at a predetermined frequency by power feed to the radiation elements  123   b  to  123   e  and radiate the radio wave. 
     The conductive ground layer  122  is shape-processed by an additive method, a subtractive method, or the like, and thus a slot  122   a  is formed in the conductive ground layer  122 . The slot  122   a  is located so as to overlap the land part  123   h  in the plan view. In other words, the slot  122   a  faces the land part  123   h.    
     The conductive pattern layer  121  is shape-processed by an additive method, a subtractive method, or the like, and thus a feed line  121   a  is formed on the conductive pattern layer  121 . The feed line  121   a  is a microstrip line wired from a terminal of an RFIC  139  to a counter position of the slot  122   a . One end part of the feed line  121   a  faces the slot  122   a , and the one end part is electrically connected to the land part  123   h  through a through hole conductor  125 . The other end part of the feed line  121   a  is connected to the terminal of the RFIC  139 . Thus, power is fed from the RFIC  139  to the element row  123   a  via the feed line  121   a  and the through hole conductor  125 . 
     The through hole conductor  125  penetrates the dielectric layer  112 , the conductive ground layer  122 , the dielectric layer  113 , and the dielectric layer  114 . At a place where the through hole conductor  125  penetrates the conductive ground layer  122 , the through hole conductor  125  is separated inward from an edge of the slot  122   a , and the through hole conductor  125  and the conductive ground layer  122  are electrically insulated from each other. Note that the through hole conductor  125  may not be formed, and the one end part of the feed line  121   a  may be electromagnetically coupled to the land part  123   h  through the slot  122   a.    
     Since a thickness of the dielectric substrate  131  falls within a range of 300 to 700 μm, a gain of the antenna  101  is high and directivity in a normal direction of a surface of the dielectric substrate  131  is strong. A result of verifying this is illustrated in  FIG.  4   . A gain of the antenna  101  is simulated when a thickness of the dielectric substrate  131  is 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, and 800 μm. In  FIG.  4   , a horizontal axis indicates an angle with reference to a normal direction of a surface of the dielectric substrate  131 , and a vertical axis indicates a gain. When a thickness of the dielectric substrate  131  is 300 μm, 400 μm, 500 μm, 600 μm, and 700 μm, directivity in the normal direction is high, and all gain in the normal direction at −30° to 30° exceeds 4 dBi and is high. When a thickness of the dielectric substrate  131  is 800 μm, directivity in the normal direction is low, and a gain in the normal direction at all angles falls below 4 dBi. Thus, it is found that, when a thickness of the dielectric substrate  131  falls within a range of 300 to 700 μm, a gain of the antenna  101  is high and directivity in the normal direction of the surface of the dielectric substrate  131  is strong. 
     The dielectric substrate  131  is rigid, and thus bending of the antenna  101  is less likely to occur. Particularly, a change in radiation characteristics of the element row  123   a  due to bending deformation of the element row  123   a  is less likely to occur. 
     The dielectric layer  112  is thin, and has a low dielectric constant and a low dielectric loss tangent. Moreover, when the protective dielectric layer  111  is not formed, the feed line  121   a  is exposed to the air, and thus a transmission loss of a signal wave in the feed line  121   a  is low. Since an electric field is mainly formed between the element row  123   a  and the conductive ground layer  122 , and the dielectric layers  114  and  116  have a low dielectric constant and a low dielectric loss tangent, a loss in the element row  123   a  is low even when the element row  123   a  is covered with the dielectric substrate  131 . Meanwhile, the dielectric substrate  131  does not need to be made thin, and it is possible to suppress narrowing of the band of the antenna  101 . 
     The element row  123   a  is a series connection body of the four radiation elements  123   b  to  123   e , but the number of radiation elements is not limited thereto as long as the number is an even number. However, it is preferable that the element row  123   a  includes four, six, or eight radiation elements. A result of verifying this is illustrated in  FIG.  5   . A gain of the antenna  101  is simulated when the number of elements in the element row  123   a  is two, four, six, and eight. In  FIG.  5   , a horizontal axis indicates a frequency, and a vertical axis indicates a gain. When the number of elements in the element row  123   a  is four, six, and eight, a frequency band in which a gain exceeds 9 dBi is 58 to 67 GHz, which is wide. When the number of elements in the element row  123   a  is two, a gain does not exceed 9 dBi in a frequency band of 56 to 68 GHz. Thus, it is found that the number of elements in the element row  123   a  is preferably four, six, and eight. 
     First Modified Example of Second Embodiment 
       FIG.  6    is a plan view of an antenna  101 A according to a modified example. As illustrated in  FIG.  6   , a plurality of sets (for example, 16 sets) of groups each formed of the element row  123   a , the parasitic elements  124   b  to  124   e , the feed line  121   a , the slot  122   a  (cf.  FIG.  3   ), and the through hole conductor  125  (cf.  FIG.  3   ) may be aligned at a predetermined pitch in a direction orthogonal to a row direction of the element row  123   a . In this case, the radiation elements  123   b  in the element rows  123   a  have identical positions in the row direction, and the radiation elements  123   b  are aligned in one row in the direction orthogonal to the row direction. The same also applies to the radiation elements  123   c  in the element rows  123   a . The same also applies to the radiation elements  123   d  in the element rows  123   a . The same also applies to the radiation elements  123   e  in the element rows  123   a.    
     A pitch D between the element rows  123   a  adjacent to each other, i.e., a gap between central lines in the row direction is 0.4 to 0.6 times a wavelength of the highest frequency to be used. A condition that a grating lobe does not fall within a visible region is D/λ&lt;1/(1+sin θ) where θ is a direction in which a radiation gain is maximum, and thus a high gain and wide-angle scanning are achieved with the plurality of radiation elements  123   b  to  123   e  aligned in a grid pattern in such a manner. 
     Second Modified Example of Second Embodiment 
       FIG.  7    is a plan view of an antenna  101 B according to a modified example. As illustrated in  FIG.  7   , two sets of groups  138  each including a plurality of sets (for example, 16 sets) of groups each formed of the element row  123   a , the parasitic elements  124   b  to  124   e , the feed line  121   a , the slot  122   a  (cf.  FIG.  3   ), and the through hole conductor  125  (cf.  FIG.  3   ) may be provided. In this case, in both of the groups  138 , the radiation elements  123   b  in the element rows  123   a  have identical positions in the row direction, and the radiation elements  123   b  are aligned in one row in the direction orthogonal to the row direction. The same also applies to the radiation elements  123   c  in the element rows  123   a . The same also applies to the radiation elements  123   d  in the element rows  123   a . The same also applies to the radiation elements  123   e  in the element rows  123   a.    
     In both of the groups  138 , a pitch between the element rows  123   a  adjacent to each other, i.e., a gap between central lines in the row direction is 2 to 2.5 mm. The row direction of the element row  123   a  in one of the groups  138  is parallel to the row direction of the element row  123   a  in the other group  138 . The RFIC  139  is disposed between the one group  138  and the other group  138 . The one group  138  is used for reception, and the other group  138  is used for transmission. In both of the groups  138 , the plurality of radiation elements  123   b  to  123   e  are aligned in a grid pattern, and thus a high gain is achieved. Note that both of the groups  138  may be used for reception or used for transmission. 
     Note that three sets or more of the groups  138  may be provided. In this case, the row directions of the element rows  123   a  in all of the groups  138  are parallel to each other. Alternatively, when there are four sets of the groups  138 , the first group  138  and the second group  138  are arranged on the left and right in the paper plane of  FIG.  7    as in  FIG.  7   , the third group  138  and the fourth group  138  are arranged on the top and bottom in the paper plane of  FIG.  7   , the RFIC  139  is arranged between the first group  138  and the second group  138 , the RFIC  139  is arranged between the third group  138  and the fourth group  138 , the row direction of the element row  123   a  in the first group  138  is parallel to the row direction of the element row  123   a  in the second group  138 , and the row direction of the element row  123   a  in the third and fourth groups  138  is perpendicular to the row direction of the element row  123   a  in the first and second groups  138 . 
     Third Modified Example of Second Embodiment 
       FIG.  8    is a plan view of an antenna  101 C. Hereinafter, a difference between the antenna  101 C illustrated in  FIG.  8    and the antenna  101  illustrated in  FIG.  2    will be described, and description of common points will be omitted. 
     In the antenna  101  illustrated in  FIG.  2   , the radiation element pattern layer  123  includes one element row  123   a , and one set of the parasitic elements  124   b  to  124   e  is also provided. 
     In contrast, in the antenna  101 C illustrated in  FIG.  8   , the radiation element pattern layer  123  is shape-processed by an additive method, a subtractive method, or the like, and thus the radiation element pattern layer  123  includes two element rows  123   a . Similarly, the parasitic element pattern layer  124  is shape-processed by an additive method, a subtractive method, or the like, and thus the parasitic element pattern layer  124  includes two sets of the parasitic elements  124   b  to  124   e.    
     One of the element rows  123   a  has a shape in which the other element row  123   a  is translated in the row direction. The radiation elements  123   b  to  123   e  in the other element row  123   a  follow the end of the rearmost radiation element  123   e  in the one element row  123   a , and the radiation elements  123   b ,  123   c ,  123   d , and  123   e  are linearly aligned in this order in one row at intervals. Therefore, the radiation elements  123   b  to  123   e  in the element rows  123   a  are linearly aligned. 
     In the one element row  123   a , the parasitic elements  124   b  to  124   e  face the radiation elements  123   b  to  123   e , respectively. Also in the other element row  123   a , the parasitic elements  124   b  to  124   e  face the radiation elements  123   b  to  123   e , respectively. 
     The conductive pattern layer  121  is shape-processed by an additive method, a subtractive method, or the like, and the conductive pattern layer  121  includes a feed line  121   b  having a T branch. The feed line  121   b  is divided into two from the RFIC  139  to the land parts  123   h  in the two element rows  123   a , and each of two divided end parts faces the land part  123   h  in each of the two element rows  123   a . Then, similarly to the antenna  101  illustrated in  FIG.  2   , the slot  122   a  is formed in each of portions of the conductive ground layer  122  facing the two divided end parts of the feed line  121   b , and each of the two divided end parts of the feed line  121   b  is electrically connected to the land part  123   h  in each of the two element rows  123   a  through the through hole conductor  125  that penetrates the dielectric layer  112 , the conductive ground layer  122 , the dielectric layer  113 , and the dielectric layer  114 . Note that each of the two divided end parts of the feed line  121   b  may be electromagnetically coupled to the land part  123   h  in each of the two element rows  123   a  through the slots  122   a.    
     An electric length from the terminal of the RFIC  139  to the land part  123   h  in the one element row  123   a  along the feed line  121   b  is equal to an electric length from the terminal of the RFIC  139  to the land part  123   h  in the other element row  123   a  along the feed line  121   b.    
     Fourth Modified Example of Second Embodiment 
       FIG.  9    is a plan view of an antenna  101 D. Hereinafter, a difference between the antenna  101 D illustrated in  FIG.  9    and the antenna  101 C illustrated in  FIG.  8    will be described, and description of common points will be omitted. 
     In the antenna  101 C illustrated in  FIG.  8   , one of the element rows  123   a  has a shape obtained by translating the other element row  123   a  in the row direction. In contrast, in the antenna  101 D illustrated in  FIG.  9   , one of the element rows  123   a  has a shape that is line symmetric with a shape of the other element row  123   a  with respect to a symmetric line orthogonal to the row direction of the other element row  123   a . The radiation elements  123   e  to  123   b  in the other element row  123   a  follow the end of the rearmost radiation element  123   e  in the one element row  123   a , and the radiation elements  123   e ,  123   d ,  123   c , and  123   b  are linearly aligned in this order in one row at intervals. Therefore, the radiation elements  123   b  to  123   e  in the element rows  123   a  are linearly aligned. 
     In the one element row  123   a , the parasitic elements  124   b  to  124   e  face the radiation elements  123   b  to  123   e , respectively. Also in the other element row  123   a , the parasitic elements  124   b  to  124   e  face the radiation elements  123   b  to  123   e , respectively. 
     A difference between an electric length from the terminal of the RFIC  139  to the land part  123   h  in the one element row  123   a  along the feed line  121   b  and an electric length from the terminal of the RFIC  139  to the land part  123   h  in the other element row  123   a  along the feed line  121   b  is equal to ½ of an effective wavelength at the center of a band to be used. 
     Fifth Modified Example of Second Embodiment 
       FIG.  10    is a plan view of an antenna  101 E. Hereinafter, a difference between the antenna  101 E illustrated in  FIG.  10    and the antenna  101 C illustrated in  FIG.  8    will be described, and description of common points will be omitted. 
     The antenna  101 C illustrated in  FIG.  8    has a shape in which one of the element rows  123   a  has the other element row  123   a  moved in translation in the row direction. In contrast, in the antenna  101 E illustrated in  FIG.  10   , one of the element rows  123   a  and the other element row  123   a  are in point symmetry. The radiation elements  123   e  to  123   b  in the other element row  123   a  follow the end of the rearmost radiation element  123   e  in the one element row  123   a , and the radiation elements  123   e ,  123   d ,  123   c , and  123   b  are linearly aligned in this order in one row at intervals. Therefore, the radiation elements  123   b  to  123   e  in the element rows  123   a  are linearly aligned. 
     In the one element row  123   a , the parasitic elements  124   b  to  124   e  face the radiation elements  123   b  to  123   e , respectively. Also in the other element row  123   a , the parasitic elements  124   b  to  124   e  face the radiation elements  123   b  to  123   e , respectively. 
     A difference between an electric length from the terminal of the RFIC  139  to the land part  123   h  in the one element row  123   a  along the feed line  121   b  and an electric length from the terminal of the RFIC  139  to the land part  123   h  in the other element row  123   a  along the feed line  121   b  is equal to ½ of an effective wavelength at the center of a band to be used. 
     Sixth Modified Examples of Second Embodiment 
       FIG.  11    is a plan view of an antenna  101 F. As in the antenna  101 F illustrated in  FIG.  11   , groups each formed of two rows each including the element row  123   a , the feed line  121   b , the parasitic elements  124   b  to  124   e , the slot  122   a  (cf.  FIG.  3   ), and the through hole conductor  125  (cf.  FIG.  3   ) illustrated in  FIG.  8    may be aligned at a predetermined pitch (for example, 2 to 2.5 mm) in the direction orthogonal to the row direction of the element row  123   a . In this case, the radiation elements located in the same position in the same order counting from the front of the two element rows  123   a  in each group have identical positions in the row direction, and the radiation elements are aligned in one row in the direction orthogonal to the row direction. 
     Note that a group formed of two element rows  123   a  illustrated in  FIG.  9  or  10   , the feed line  121   b , the parasitic elements  124   b  to  124   e , the slot  122   a  (cf.  FIG.  3   ), and the through hole conductor  125  (cf.  FIG.  3   ) may be aligned at a predetermined pitch (for example, 2 to 2.5 mm) in the direction orthogonal to the row direction of the element row  123   a.    
     Two groups (cf.  FIG.  11   ) including a plurality of sets (for example, 16 sets) of groups each formed of the two element rows  123   a , the feed line  121   b , the parasitic elements  124   b  to  124   e , the slot  122   a  (cf.  FIG.  3   ), and the through hole conductor  125  (cf.  FIG.  3   ) may be provided. In this case, the row directions of the element rows  123   a  in all of the groups are parallel to each other. 
     Third Embodiment 
       FIG.  12    is a plan view of an antenna  201  according to a third embodiment.  FIG.  13    is a cross-sectional view taken along XIII-XIII in  FIG.  12   . Hereinafter, a difference between the antenna  201  according to the third embodiment and the antenna  101  according to the second embodiment will be described, and description of common points will be omitted. 
     In the second embodiment, the radiation element pattern layer  123  is formed between the dielectric layer  114  and the dielectric layer  115 , and the parasitic element pattern layer  124  is formed between the dielectric layer  116  and the adhesive layer  119 . In contrast, in the third embodiment, a parasitic element pattern layer  124  is formed between a dielectric layer  114  and a dielectric layer  115 , and a radiation element pattern layer  123  is formed between a dielectric layer  116  and an adhesive layer  119 . In the third embodiment, the adhesive layer  119  is thicker than a radiation elements  123   b  to  123   e . Thus, a void is less likely to be generated around the radiation elements  123   b  to  123   e  at a bonding interface between the adhesive layer  119  and the dielectric layer  116 . 
     In the second embodiment, the through hole conductor  125  penetrates the dielectric layer  112 , the conductive ground layer  122 , the dielectric layer  113 , and the dielectric layer  114 . In contrast, in the third embodiment, a through hole conductor  125  penetrates a dielectric layer  112 , a conductive ground layer  122 , a dielectric layer  113 , the dielectric layer  114 , the dielectric layer  115 , and the dielectric layer  116 . 
     In the second embodiment, the parasitic element  124   b  is smaller than the radiation element  123   b . In contrast, in the third embodiment, a parasitic element  124   b  is larger than the radiation element  123   b , and the entire radiation element  123   b  is located inside an outer shape of the parasitic element  124   b  in the plan view. The reason is that, if the parasitic element  124   b  is smaller than the radiation element  123   b , a radiation gain decreases at a high frequency. Similarly, a side of the radiation element  123   c  perpendicular to a polarization direction is located inside a side of a parasitic element  124   c  perpendicular to the polarization direction in the plan view, and a side of the radiation element  123   d  perpendicular to the polarization direction is located inside a side of a parasitic element  124   d  perpendicular to the polarization direction in the plan view. 
     Also in the third embodiment, the parasitic elements  124   b  to  124   e  and the radiation elements  123   b  to  123   e  are different from each other in size, and thus different from each other in a resonant frequency. In other words, the antenna  201  has frequency characteristics such that a gain at a resonant frequency of the radiation elements  123   b  to  123   e  and a resonant frequency of the parasitic elements  124   b  to  124   e  takes a local maximum value. Thus, a use band of the antenna  201  is widened. 
     In the third embodiment, in a case of a low frequency, the parasitic elements  124   b  to  124   e  also function as a radiation element, and the radiation elements  123   b  to  123   e  also function as a wave director. In a case of a high frequency, the parasitic elements  124   b  to  124   e  function as a reflector that reflects a radio wave from a dielectric substrate  131  side to the radiation elements  123   b  to  123   e.    
     A modification point in the first to sixth modified examples of the second embodiment may be applied to the third embodiment (cf.  FIGS.  14  to  19   ). 
     Verification 1 
     As in the antenna  101  illustrated in  FIGS.  2  and  3   , widening of a band of the antenna  101  by the parasitic elements  124   b  to  124   e  facing the radiation elements  123   b  to  123   e , respectively, is verified by a simulation. A result of the simulation is illustrated in  FIGS.  20  and  21   . 
     In  FIG.  20   , a vertical axis represents a reflection coefficient (S 11 ), and a horizontal axis represents a frequency. A solid line represents a simulation result when the parasitic elements  124   b  to  124   e  are provided, and a broken line represents a simulation result when the parasitic elements  124   b  to  124   e  are not provided. As is clear from  FIG.  20   , when the parasitic elements  124   b  to  124   e  are provided, a reflection coefficient is equal to or less than −10 dB even in a region at 67 GHz or greater, whereas when the parasitic elements  124   b  to  124   e  are not provided, a reflection coefficient increases in the region at 67 GHz or greater. Thus, it is found that the antenna  101  has a wider band when the parasitic elements  124   b  to  124   e  are provided. 
     In  FIG.  21   , a vertical axis represents a gain, and a horizontal axis represents a frequency. A solid line represents a simulation result when the parasitic elements  124   b  to  124   e  are provided, and a broken line represents a simulation result when the parasitic elements  124   b  to  124   e  are not provided. As is clear from  FIG.  21   , when the parasitic elements  124   b  to  124   e  are provided, a gain does not decrease even in a region at 67 GHz or greater, whereas when the parasitic elements  124   b  to  124   e  are not provided, a gain decreases in the region at 67 GHz or greater. Thus, it is found that the antenna  101  has a wider band when the parasitic elements  124   b  to  124   e  are provided. 
     Verification 2 
     In the antenna  101  illustrated in  FIGS.  2  and  3   , a change in reflection characteristics of the antenna  101  due to a change in length ratio of the parasitic elements  124   b  to  124   e  and the radiation elements  123   b  to  123   e  in the polarization direction is verified by a simulation. A result of the simulation is illustrated in  FIGS.  22  and  23   . 
     In  FIG.  22   , a vertical axis represents a gain, and a horizontal axis represents a frequency. In  FIG.  23   , a vertical axis represents a reflection coefficient (S 11 ), and a horizontal axis represents a frequency. As is clear from  FIGS.  22  and  23   , the antenna  101  has a wider band when a length of the parasitic elements  124   b  to  124   e  in the polarization direction is 95% of a length of the radiation elements  123   b  to  123   e  in the polarization direction than when a length of the parasitic elements  124   b  to  124   e  in the polarization direction is 100% of a length of the radiation elements  123   b  to  123   e  in the polarization direction. 
     It can be confirmed that the antenna  101  has a wider band in a range in which a length of the parasitic elements  124   b  to  124   e  in the polarization direction is 95 to 70% of a length of the radiation elements  123   b  to  123   e  in the polarization direction. However, widening of a band of the antenna  101  is substantially the same in a range in which a length of the parasitic elements  124   b  to  124   e  in the polarization direction is equal to or less than 70% of a length of the radiation elements  123   b  to  123   e  in the polarization direction. 
     Therefore, it is preferable that a length of the parasitic elements  124   b  to  124   e  in the polarization direction is 70 to 95% of a length of the radiation elements  123   b  to  123   e  in the polarization direction. 
     When a length of the parasitic elements  124   b  to  124   e  in the polarization direction is 80 to 95% of a length of the radiation elements  123   b  to  123   e  in the polarization direction, a gain is higher in a necessary band and reflection is more easily suppressed in a necessary band, and thus it is more preferable that a length of the parasitic elements  124   b  to  124   e  in the polarization direction is 80 to 95% of a length of the radiation elements  123   b  to  123   e  in the polarization direction. 
     Furthermore, when a length of the parasitic elements  124   b  to  124   e  in the polarization direction is 85 to 90% of a length of the radiation elements  123   b  to  123   e  in the polarization direction, a gain is even higher in a necessary band and reflection is easily suppressed in a necessary band, and thus it is more preferable that a length of the parasitic elements  124   b  to  124   e  in the polarization direction is 85 to 90% of a length of the radiation elements  123   b  to  123   e  in the polarization direction. 
     REFERENCE SIGNS LIST 
     
         
           1 : Antenna; 
           10 : Dielectric laminated body; 
           11 : Protective dielectric layer; 
           12  to  16 : Dielectric layer; 
           19 : Adhesive layer; 
           21 : Conductive pattern layer; 
           21   a : Feed line; 
           22 : Conductive ground layer; 
           22   a : Slot; 
           23 : Radiation element pattern layer; 
           23   a : Radiation element; 
           24 : Passive element pattern layer; 
           24   a : Passive element; 
           25 : Through hole conductor; 
           31 : Dielectric substrate; 
           101 ,  101 A,  101 B,  101 C,  101 D,  101 E,  101 F: Antenna; 
           201 ,  201 A,  201 B,  201 C,  201 D,  201 E,  201 F: Antenna; 
           110 : Dielectric laminated body; 
           111 : Protective dielectric layer; 
           112  to  116 : Dielectric layer; 
           119 : Adhesive layer; 
           121 : Conductive pattern layer; 
           121   a ,  121   b : Feed line; 
           122 : Conductive ground layer; 
           122   a : Slot; 
           123 : Radiation element pattern layer; 
           123   a : Element row; 
           123   b  to  123   e : Radiation element; 
           124 : Passive element pattern layer; 
           124   b  to  124   e : Passive element; 
           125 : Through hole conductor; 
           131 : Dielectric substrate; 
           138 : Group.