Patent Publication Number: US-9843094-B2

Title: Glass antenna for vehicle

Description:
TECHNICAL FIELD 
     The present invention relates to a glass antenna provided on a side glass of a vehicle and relates to a glass antenna for the vehicle which is suitable to receive radio wave of FM radio broadcast wave. 
     BACKGROUND ART 
     Frequency band for the FM radio broadcast in Japan is 76 MHz˜90 MHz, and frequency band for the FM radio broadcast except Japan is 88 MHz˜108 MHz. 
     For instance, as disclosed in a related art of Japanese Patent Provisional Publication No. 10-13127 (JP10-13127), in a vehicle having a large-sized side glass, a glass antenna to receive FM broadcast wave and AM broadcast wave is provided on the side glass (Patent Document 1). 
     With respect to the FM broadcast wave, in general, by adjusting a length of the antenna to establish resonance with a frequency band of the FM broadcast wave, a good reception gain can be obtained. With regard to the AM broadcast wave, as shown by a circle drawn by a dotted line which encircles a conductive line in  FIGS. 12A and 12B , the conductive line each has a reception effective area for AM wave, and it is generally known that the greater the an area encircled by this circle, the more suitably the AM broadcast wave can be received. For instance, as compared with  FIG. 12B  in which two reception effective areas of a horizontal part of each conductive line located at a lower side of the side glass overlap with each other, a reception effective area of the glass antenna provided on the side glass for the AM broadcast wave as shown in  FIG. 12A  in which the two reception effective areas of the horizontal part of each conductive line do not overlap with each other becomes greater. 
     Regarding the glass antenna for the vehicle disclosed in the Patent Document 1, it is an antenna that can receive both of the FM radio broadcast wave and the AM radio broadcast wave by the fact that a conductive line connecting to a power feeding portion that is disposed at a corner part of the side glass is set to form an S-shape. For the FM broadcast wave, by arranging the conductive line so as to form the S-shape on the side glass, a sufficient length of this antenna to establish resonance with the frequency band of the FM broadcast wave can be obtained. In addition, for the AM broadcast wave, by disposing a part of the S-shaped conductive line so as to extend in the middle of the side glass, the reception effective area of the conductive line of this antenna can be increased. 
     Further, in this antenna, by connecting an auxiliary line to the S-shaped conductive line and matching an input impedance of the power feeding portion of this antenna with a characteristic impedance of a power feeding line connected to the power feeding portion, the reception gain of the FM broadcast wave can be increased. 
     CITATION LIST 
     Patent Document 
     Patent Document 1: Japanese Patent Application Publication No. JP10-13127 
     SUMMARY OF THE INVENTION 
     Technical Problem 
     In the antenna disclosed in the Patent Document 1, however, there could be a case where a high reception gain can not be obtained over the full range of a desired frequency band of the FM broadcast wave, depending on a shape of the side glass or depending on the vehicle having the side glass. 
     The present invention solves this problem. That is, the present invention is aimed at providing the glass antenna for the side glass which is capable of obtaining the high reception gain over the full range of the desired frequency band of the FM broadcast wave. 
     Solution to Problem 
     A glass antenna of the present invention is a glass antenna of a vehicle for receiving FM broadcast wave, which has a power feeding portion provided at a side portion of a side glass of the vehicle and a main element connected to the power feeding portion. Further, the glass antenna of the present invention has a square bracket-shaped element arranged at an outer side of the main element. And one end of the square bracket-shaped element is connected to some midpoint of the main element. 
     Then, when a wavelength of a center frequency of frequency band of a low frequency with respect to a center frequency of frequency band of the FM broadcast wave received by the glass antenna is λ and a wavelength of a center frequency of frequency band of a high frequency with respect to the center frequency of frequency band of the FM broadcast wave received by the glass antenna is λ′, and also when a wavelength shortening coefficient of the side glass is α, and further when a length of the main element is L1, a length of the square bracket-shaped element is L2 and a length from the some midpoint of the main element at which the square bracket-shaped element is connected up to the power feeding portion is L3, these L1, L2 and L3 are set so as to satisfy a following relationship; L1=α·λ·¾, L2+L3=α·λ′·¾ or L1=α·λ′·¾, L2+L3=α·λ·¾. 
     Further, by arranging a part of the main element so as to extend from one side portion up to an opposite side portion of the side glass in a lateral direction on a center line of the side glass or in close proximity to the center line of the side glass, a good reception performance of AM broadcast wave can be obtained. 
     Furthermore, by arranging the dummy element to be parallel to a part of the square bracket-shaped element where the square bracket-shaped element does not extend along the main element, an appearance of the glass antenna of the present invention can be enhanced. 
     In the present invention, it is preferable that the square bracket-shaped element be arranged at a clearance of 10 mm or more from a flange peripheral edge of the vehicle where the side glass is mounted. 
     In the present invention, it is preferable that a part of the square bracket-shaped element which extends along the main element be arranged at a distance of 10 mm or more from the main element. 
     Effects of the Invention 
     According to the present invention, the length of one of two elements, which are provided on the side glass and form the glass antenna for the vehicle, is adjusted to the wavelength of the center frequency on the lower frequency band side of the desired frequency band of the FM broadcast wave, and the other of the two elements is adjusted to the wavelength of the center frequency on the higher frequency band side of the desired frequency band of the FM broadcast wave. Then, by properly connecting these two elements and properly arranging these two elements on the side glass, the high reception gain can be obtained over the full range of the desired frequency band of the FM broadcast wave. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a glass antenna for a vehicle according to an embodiment 1. 
         FIG. 2  is a front view of a glass antenna for the vehicle according to an embodiment 2. 
         FIG. 3  is a front view of a glass antenna for the vehicle according to an embodiment 3. 
         FIG. 4  is a front view of a glass antenna for the vehicle according to an embodiment 4. 
         FIG. 5  is a front view of a glass antenna for the vehicle according to an embodiment 5. 
         FIG. 6  is a front view of a glass antenna for the vehicle according to an embodiment 6. 
         FIG. 7  is a front view of a glass antenna for the vehicle according to an embodiment 7. 
         FIG. 8  is a front view of a glass antenna for the vehicle according to an embodiment 8. 
         FIG. 9  is a front view of a glass antenna for the vehicle according to an embodiment 9. 
         FIG. 10  is a front view of a glass antenna for the vehicle of a comparative example. 
         FIG. 11  is a frequency response characteristic with a reception gain at each frequency compared between the embodiment 1 and the comparative example. 
         FIGS. 12A and 12B  are reference examples for explaining a reception effective area for AM broadcast wave. 
     
    
    
     EMBODIMENTS FOR CARRYING OUT THE INVENTION 
     &lt;General Configuration of the Present Invention&gt; 
     A glass antenna  2  of the present invention is an antenna as shown by a front view of a side glass  1 , viewed from a vehicle exterior side, in  FIG. 1 . The glass antenna  2  of the present invention has a power feeding portion  21 , a main element  22  and a square bracket-shaped element  23  on the side glass  1  that is mounted on or fitted into a side flange of a vehicle. The square bracket-shaped element  23  is arranged at an outer side of the main element  22 . Further, the glass antenna  2  could have a dummy element  24 . 
     The power feeding portion  21  can be provided at a side portion of the side glass  1 , for instance, at a left side portion of the side glass  1 . One end of the main element  22  is connected to the power feeding portion  21 , and the other end of the main element  22  is open. With regard to the square bracket-shaped element  23 , its one end is connected to some midpoint of the main element  22 , and the square bracket-shaped element  23  is arranged at the outer side of the main element  22  so as to extend along a periphery of the side glass  1 . 
     The dummy element  24  is an element provided with the aim of enhancing an appearance of the antenna. The dummy element  24  is not connected to the main element  22  nor the square bracket-shaped element  23 . The dummy element  24  is arranged so as to extend along a part of the square bracket-shaped element  23  where the square bracket-shaped element  23  does not extend along the main element  22 . 
     Then, a length of the main element  22  and a length of the square bracket-shaped element  23  are determined as follows. That is, when a wavelength of a center frequency of frequency band of a low frequency with respect to a center frequency of frequency band of FM broadcast wave received by the glass antenna  2  is λ and a wavelength of a center frequency of frequency band of a high frequency with respect to the center frequency of frequency band of the FM broadcast wave received by the glass antenna  2  is λ′, and also when a wavelength shortening coefficient (or a wavelength compaction ratio) of the side glass  1  is α, either one of the length of the main element  22  or a length obtained by adding a length from the power feeding portion  21  up to a connecting point between the main element  22  and the square bracket-shaped element  23  to the length of the square bracket-shaped element  23  is adjusted to almost α·λ·¾, and the other is adjusted to almost α·λ′·¾. Further, a position of the connecting point of the square bracket-shaped element  23  with the main element  22  is adjusted. With these setting, it is possible to obtain a high reception gain over a full range of a desired frequency band of the FM broadcast wave. 
     &lt;Pattern of Main Element&gt; 
     The main element  22  has a first line  221  that extends straight in a lateral direction, a second line  222  that extends straight in the lateral direction and a third line  223  that extends in a longitudinal direction. In  FIG. 1 , the power feeding portion  21  is disposed at the left side portion of the side glass  1 . Then, in a case where the main element  22  is elongated from the power feeding portion  21  in a direction of an upper side of the side glass  1 , each line of the main element  22  is arranged in a clockwise direction from the power feeding portion  21  up to a connecting point between the second line  222  and the third line  223 . 
     The first line  221  is a line whose one end is connected to the power feeding portion  21 . In  FIG. 1 , the first line  221  is arranged at the upper side of the side glass  1 , and left and right end portions of the first line  221  are bent. A first bending portion  221   a  of the first line  221 , which is disposed so as to extend along a right side of the side glass  1 , and a second bending portion  221   b  of the first line  221 , which is disposed so as to extend along a left side of the side glass  1 , are formed on the side glass  1 . A top end of the first bending portion  221   a  of the first line  221  is connected to one end of the second line  222 , and a top end of the second bending portion  221   b  of the first line  221  is connected to the power feeding portion  21 . 
     The second line  222  is positioned in a middle of the side glass  1  with respect to the first line  221 . The second line  222  is arranged parallel to the upper side of the side glass  1 , and extends or reaches up to both left and right sides of the side glass  1 . The one end of the second line  222  is connected to the top end of the first bending portion  221   a  of the first line  221 , and another one end (the other end) of the second line  222  is elongated up to the left side portion of the side glass  1  and connected to a top end of the third line  223 . 
     The third line  223  is arranged so as to extend along the left side of the side glass  1 . One end of the third line  223  is connected to the top end of the second line  222 , and the third line  223  is elongated in a direction moving away from the power feeding portion  21 , then another one end (the other end) of the third line  223  is open. 
     [Relationship Between Power Feeding Portion and Main Element] 
     The power feeding portion  21  is disposed not only at the left side portion of the side glass  1 , but as shown in  FIGS. 8 and 9 , the power feeding portion  21  could be disposed also at a right side portion of the side glass  1 . In a case where, as shown in  FIG. 9 , the power feeding portion  21  is disposed at the right side portion of the side glass  1  and the main element  22  is elongated from the power feeding portion  21  in a direction of the upper side of the side glass  1 , each line of the main element  22  is arranged in a counterclockwise direction from the power feeding portion  21  up to the connecting point between the second line  222  and the third line  223 . Further, in a case where, as shown in  FIG. 8 , the power feeding portion  21  is disposed at the right side portion of the side glass  1  and the main element  22  is elongated from the power feeding portion  21  in a direction of a lower side of the side glass  1 , each line of the main element  22  is arranged in a clockwise direction from the power feeding portion  21  up to the connecting point between the second line  222  and the third line  223 . 
     Further, as shown in  FIG. 4 , the power feeding portion  21  could be disposed at a corner part of the side glass  1 . In this case, in order for the first line  221  of the main element  22  to connect to the power feeding portion  21 , there is no need to form the second bending portion  221   b  of the first line  221 . The first line  221  is elongated straight from the power feeding portion  21  along one of the upper side or the lower side of the side glass  1  where the power feeding portion  21  is disposed along the side of the side glass  1 . 
     [Position of Second Line of Main Element] 
     A position of the second line  222  of the main element  22  greatly affects a reception performance of the AM broadcast wave. As shown in  FIGS. 6 and 7 , with respect to the FM broadcast wave, even if the second line  222  is positioned at a position that is separate from a center line e of the side glass  1  which is parallel to the upper side of the side glass  1 , a reception performance of the FM broadcast wave is not greatly affected. However, with regard to the AM broadcast wave, as shown in  FIGS. 12A and 12B , each line of the main element  22  has a reception effective area for AM broadcast wave as indicated by an area encircled by a dotted line (a dotted circle). Thus, as shown in  FIG. 12B , if the lines of the main element  22  overlap with each other, the reception effective area of the glass antenna  2  becomes small then the reception performance of the AM broadcast wave lowers, as compared with the case where, as shown in  FIG. 12A , the lines of the main element  22  are separate from each other. 
     Therefore, as shown in  FIGS. 1 to 5  and  FIGS. 8 and 9 , when the second line  222  is arranged in close proximity to the center line e of the side glass  1 , the reception effective area for AM broadcast wave can be a maximum. Hence, as compared with  FIGS. 6 and 7  in which the second line  222  is positioned at the position that is separate from the center line e of the side glass  1 , it is possible to receive the AM broadcast wave more suitably. 
     [Pattern of Third Line of Main Element] 
     As a pattern of the third line  223  of the main element  22 , as shown in  FIG. 1 , an entire length of the third line  223  is elongated along the side portion of the side glass  1 , or as shown in  FIG. 5 , a top end of the third line  223  is bent. This is because the length of the main element  22  is set to α·λ·¾ or α·λ′·¾ in accordance with a size of the side glass on which the glass antenna  2  is provided. 
     &lt;Square Bracket-Shaped Element&gt; 
     With regard to the square bracket-shaped element  23 , for instance, as shown in  FIG. 1 , it is connected to a bending point  221   c  of the second bending portion  221   b  of the first line  221  of the main element  22 . Further, the square bracket-shaped element  23  is elongated along the upper side of the side glass  1  at the outer side of the first line  221 , is bent at a right upper side portion corner part of the side glass  1 , and is elongated along the right side of the side glass  1 , and further is bent at a right lower side portion corner part of the side glass  1 , then is elongated along the lower side of the side glass  1 . 
     Since the length of the square bracket-shaped element  23  is almost α·λ·¾ or almost α·λ′·¾, in order for the length of the square bracket-shaped element  23  to be set to one of these lengths in accordance with the size of the side glass  1 , by turning back a top end portion of the square bracket-shaped element  23  as shown in  FIG. 1  or only elongating the top end portion of the square bracket-shaped element  23  straight without turning back the top end portion of the square bracket-shaped element  23  as shown in  FIGS. 3 and 4 , an adjustment of the length of the square bracket-shaped element  23  is made. 
     [Connecting Point Between Square Bracket-Shaped Element and Main Element] 
     A distance of the connecting point between a top end of the square bracket-shaped element  23  and the main element  22  from a power feeding point is important to properly match an impedance at the power feeding portion  21  of the present invention with the power feeding point. 
     In  FIG. 1 , the connecting point is provided at the bending point  221   c  of the second bending portion  221   b  of the first line  221 . With this setting, since the main element  22  and the square bracket-shaped element  23  are arranged with these elements being parallel to each other along the upper side of the side glass  1  from the left side portion to the right side portion of the side glass  1 , as compared with a case where, e.g. as shown in  FIG. 4 , the square bracket-shaped element  23  is connected to a position of the first line  221 , except the both left and right side portions, at which a desired reception gain can be obtained, the appearance of the antenna can be enhanced. 
     However, if there is no need to enhance the appearance, as shown in  FIG. 4 , even if the top end of the square bracket-shaped element  23  is connected to a portion of the first line  221  where the first line  221  extends along the upper side of the side glass  1 , the reception performance is unaffected. 
     &lt;Dummy Element&gt; 
     The dummy element  24  is an element that does not affect a performance of the glass antenna  2  and is an element provided to enhance the appearance of the glass antenna  2  of the present invention. Thus, if there is no need to consider enhancing the appearance, as shown in  FIG. 2 , no dummy element is provided. 
     As shown in  FIG. 1 , the dummy element  24  is not connected to the main element  22  nor the square bracket-shaped element  23 . The dummy element  24  is arranged so as to extend along a part of the square bracket-shaped element  23  where the square bracket-shaped element  23  does not extend along the main element  22 . When the dummy element  24  is provided, since each side of the side glass  1  except the side of the power feeding portion  21  looks as if a double frame is disposed, it is possible to enhance the appearance of the glass antenna, as compared with the case where the dummy element  24  is not provided. 
     &lt;Clearance Between Flange and Square Bracket-Shaped Element and Distance Between Square Bracket-Shaped Element and Each Element&gt; 
     When a clearance between a flange peripheral edge  3  and the square bracket-shaped element  23  is 10 mm or more, it is possible to prevent a decrease of the reception gain of the glass antenna  2  due to an electrical influence from a vehicle body. Further, when a distance between the square bracket-shaped element  23  and the main element  22  is also 10 mm or more, it is possible to prevent a decrease of the reception gain of the glass antenna  2  which is caused by a mutual electrical influence between the square bracket-shaped element  23  and the main element  22 . 
     Here, the side glass  1  shown in  FIGS. 1 to 9  is a side glass that is mounted on or fitted into a right side flange, when viewing the vehicle from a front, of the vehicle. As a matter of course, when the glass antenna of the present invention is provided on a side glass that is mounted on or fitted into a left side flange of the vehicle, as same as the case where the side glass  1  is mounted on or fitted into the right side flange and the glass antenna  2  of the present invention is provided on the side glass  1 , a good performance can be obtained. 
     &lt;Connection Between Power Feeding Portion and Power Feeding Line&gt; 
     The glass antenna  2  is provided with a ground point (not shown) on the vehicle body in close proximity to the power feeding portion  21 . Further, a receiver (not shown) and the ground point are connected by a coaxial cable (not shown). An outer sheath side of the coaxial cable is grounded or earthed, while a core wire side of the coaxial cable is connected to an AV line (not shown), then the ground point and the power feeding portion  21  are connected. 
     &lt;Forming Method of Each Line of the Present Invention&gt; 
     The glass antenna  2  can be formed using a generally used conductive ceramic paste which is the same conductive ceramic paste used when forming a defogger of a rear glass of the vehicle. The pattern of the glass antenna  2  can be formed by printing the conductive ceramic paste and burning or baking the printed conductive ceramic paste in a heating furnace, which is same as a forming method of the defogger. Or alternatively, a pattern is printed on a bright film (a transparent film) with a conductive paint, then this printed pattern is pasted on the side glass  1 , thereby forming the pattern of the glass antenna  2 . 
     EMBODIMENTS 
     In the following description, each embodiment of the present invention will be explained. 
     Embodiment 1 
       FIG. 1  is a front view of a glass antenna according to an embodiment 1 of the present invention, when viewed from a vehicle exterior side. A glass antenna  2  of the embodiment 1 has a power feeding portion  21 , a main element  22  and a square bracket-shaped element  23  on the side glass  1  that is mounted on or fitted into a side flange of a vehicle. Further, the glass antenna  2  has a dummy element  24 . 
     The power feeding portion  21  is provided at a left side portion of the side glass  1 . One end of the main element  22  is connected to the power feeding portion  21 , and the other end of the main element  22  is open. With regard to the square bracket-shaped element  23 , its one end is connected to some midpoint of the main element  22 , and the square bracket-shaped element  23  is arranged at the outer side of the main element  22  so as to extend along a periphery of the side glass  1 . The dummy element  24  is arranged so as to extend along a part of the square bracket-shaped element  23  where the square bracket-shaped element  23  does not extend along the main element  22 . 
     The main element  22  has a first line  221 , a second line  222  and a third line  223 . 
     The first line  221  is arranged at the upper side of the side glass  1 , and left and right end portions of the first line  221  are bent. A first bending portion  221   a  of the first line  221 , which is disposed so as to extend along a right side of the side glass  1 , and a second bending portion  221   b  of the first line  221 , which is disposed so as to extend along a left side of the side glass  1 , are formed on the side glass  1 . A top end of the first bending portion  221   a  of the first line  221  is connected to one end of the second line  222 , and a top end of the second bending portion  221   b  of the first line  221  is connected to the power feeding portion  21 . 
     The second line  222  is a line that is parallel to the upper side of the side glass  1  and is positioned and extends in close proximity to a center line e of the side glass  1  and also reaches up to both left and right sides of the side glass  1 . The one end of the second line  222  is connected to the top end of the first bending portion  221   a  of the first line  221 , and another one end (the other end) of the second line  222  is connected to a top end of the third line  223 . 
     The third line  223  is arranged so as to extend along the left side of the side glass  1 . One end of the third line  223  is connected to the top end of the second line  222 , and the third line  223  is elongated in a direction moving away from the power feeding portion  21 , then another one end (the other end) of the third line  223  is open. 
     The square bracket-shaped element  23  is connected to a bending point  221   c  of the second bending portion  221   b  of the first line  221  of the main element  22 . Further, the square bracket-shaped element  23  is elongated along the upper side of the side glass  1  at the outer side of the first line  221 , is bent at a right upper side portion corner part of the side glass  1 , and is elongated along the right side of the side glass  1 , and further is bent at a right lower side portion corner part of the side glass  1 , then is elongated along the lower side of the side glass  1 . Then, a top end portion of the square bracket-shaped element  23  is turned back, and a turning-back portion  23   a  of the square bracket-shaped element  23  is formed. 
     &lt;Measurement Result when Adjusting Configuration of Antenna of Embodiment 1 in Accordance with Frequency Band of FM Broadcast Wave Outside Japan&gt; 
     When adjusting a configuration of the glass antenna  2  of the present embodiment to properly receive the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan, each size is as follows.
     a lateral width a of flange=672 mm   a longitudinal width b of flange=414 mm   a length of main element  22 =1541 mm   a length obtained by adding a length of second bending portion  221   b  of main element  22  to a length of square bracket-shaped element  23 =1697 mm   a length of first bending portion  221   a  of main element  22 =173 mm   a length of second bending portion  221   b  of main element  22 =67 mm   a length of second line  222  of main element  22 =588 mm   a length of third line  223  of main element  22 =130 mm   a clearance c between square bracket-shaped element  23  and flange peripheral edge  3 =10 mm   a clearance c′ between second bending portion  221   b  of main element  22  and flange peripheral edge  3 =10 mm, and a clearance c′ between third line  223  of main element  22  and flange peripheral edge  3 =10 mm   a distance d between main element  22  and square bracket-shaped element  23 =20 mm   a distance d′ between dummy element  24  and square bracket-shaped element  23 =20 mm   

     Here, with regard to the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , when the wavelength shortening coefficient (or the wavelength compaction ratio) α=0.7, and also when a wavelength of a center frequency 103 MHz of a frequency band which is higher than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ′ and a wavelength of a center frequency 93 MHz of a frequency band which is lower than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ, α·λ′·¾=1529 mm and α·λ·¾=1694 mm. The length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  are adjusted to become almost these lengths 1529 mm and 1694 mm respectively. 
     Further, in addition to the adjustment of the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , the length of the second bending portion  221   b  of the main element  22  is also adjusted, then these adjustment is made so that the reception gain of the antenna of the present embodiment becomes a maximum. 
     A pattern of the glass antenna of the present embodiment is printed on the side glass  1  on a vehicle interior side with the conductive ceramic paste so that each line width is 0.5 mm, and after drying the pattern (after the pattern dries), the printed conductive ceramic paste is burned or baked in the heating furnace. Further, the AV line is fixed to the power feeding portion  21 , and the side glass  1  on which the pattern of the glass antenna is provided is mounted to the vehicle body. Furthermore, an outer sheath conductive line of the coaxial cable that extends from a tuner (not shown) is grounded or earthed at the ground point provided on the vehicle body in close proximity to the power feeding portion, while the core wire side of the coaxial cable is connected to the AV line. 
     When receiving the broadcast wave of the frequency 76 MHz˜108 MHz of the FM frequency band inside and outside Japan by the glass antenna of the present embodiment formed in this way, a result shown in  FIG. 11  was obtained. 
       FIG. 11  is the measurement result of the glass antenna  2  of the present embodiment and a glass antenna of an after-mentioned comparative example (which is an antenna that has only the main element  22  but does not have the square bracket-shaped element  23 . A length of the main element  22  of the glass antenna is adjusted in accordance with the frequency band of the FM broadcast wave outside Japan.), and shows the reception gain at each frequency of 76 MHz˜108 MHz. Here, the reception gain indicates an average of a reception gain obtained at each angle in all directions. In  FIG. 11 , a solid line indicates the measurement result of the glass antenna  2  of the present embodiment, and a broken line indicates the measurement result of the comparative example. 
     When viewing  FIG. 11 , in the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan, regarding the measurement result of the comparative example indicated by the broken line, although the reception gain is a maximum at 92 MHz, the reception gain greatly decreases with increase of the frequency from this frequency. On the other hand, as for the glass antenna  2  of the present embodiment, the reception gain is almost constant at 90 MHz˜98 MHz. In addition, the decrease of the reception gain is small even at a higher frequency than 98 MHz. It is understood that a high reception gain can be obtained over the full range of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan. 
     As described above, by properly adjusting the connecting point of the square bracket-shaped element  23  with the main element  22  and properly adjusting the length of each element, the excellent reception of the FM broadcast wave can be achieved at the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan. 
     In the glass antenna of the present embodiment, the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, whereas the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan. However, even if the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave outside Japan. 
     Further, in the glass antenna of the present embodiment, although the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave outside Japan, if the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave inside Japan, as same as the glass antenna of the present embodiment, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave inside Japan. 
     Furthermore, in the glass antenna of the present embodiment, the second line  222  of the main element  22  is arranged so as to extend along the center line e of the side glass  1 . Thus, the reception effective area for the AM broadcast wave can be increased, thereby also excellently receiving the AM broadcast wave by the glass antenna of the present embodiment. 
     Embodiment 2 
       FIG. 2  is a front view of a glass antenna according to an embodiment 2 of the present invention, when viewed from the vehicle exterior side. The glass antenna of the embodiment 2 is different from the glass antenna of the embodiment 1 in the respect that the glass antenna of the embodiment 2 does not have the dummy element  24 . The glass antenna of the embodiment 2 is the same as the glass antenna of the embodiment 1 except for this respect. 
     A pattern of the glass antenna of the present embodiment is printed on the side glass  1  on a vehicle interior side with the conductive ceramic paste so that each line width is 0.5 mm, and after drying the pattern (after the pattern dries), the printed conductive ceramic paste is burned or baked in the heating furnace. Further, the AV line is fixed to the power feeding portion  21 , and the side glass  1  on which the pattern of the glass antenna is provided is mounted to the vehicle body. Furthermore, an outer sheath conductive line of the coaxial cable that extends from a tuner (not shown) is grounded or earthed at the ground point provided on the vehicle body in close proximity to the power feeding portion, while the core wire side of the coaxial cable is connected to the AV line. 
     When receiving the broadcast wave of the frequency 88 MHz˜108 MHz of the FM frequency band outside Japan by the glass antenna of the present embodiment formed in this way, as same as the glass antenna of the embodiment 1, a good reception performance can be obtained at the frequency band of the FM broadcast wave outside Japan. 
     Further, in the glass antenna of the present embodiment, although the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave outside Japan, if the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave inside Japan, as same as the glass antenna of the present embodiment, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave inside Japan. 
     Furthermore, in the glass antenna of the present embodiment, the second line  222  of the main element  22  is arranged so as to extend along the center line e of the side glass  1 . Thus, the reception effective area for the AM broadcast wave can be increased, thereby also excellently receiving the AM broadcast wave by the glass antenna of the present embodiment. 
     Embodiment 3 
       FIG. 3  is a front view of a glass antenna according to an embodiment 3 of the present invention, when viewed from the vehicle exterior side. The glass antenna of the embodiment 3 is different from the glass antenna of the embodiment 1 in the respect that the top end portion of the square bracket-shaped element  23  is not turned back. The reason why the top end portion of the square bracket-shaped element  23  is not turned back in this manner is because a size of the side glass  1  on which the glass antenna of the embodiment 3 is provided is greater than a size of the side glass  1  on which the glass antenna of the embodiment 1 is provided. 
     With regard to the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , when the wavelength shortening coefficient (or the wavelength compaction ratio) α=0.7, and also when the wavelength of the center frequency 103 MHz of the frequency band which is higher than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ′ and the wavelength of the center frequency 93 MHz of the frequency band which is lower than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ, α·λ′·¾=1529 mm and α·λ·¾=1694 mm. The length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  are adjusted to become almost these lengths 1529 mm and 1694 mm respectively. 
     Further, in addition to the adjustment of the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , the length of the second bending portion  221   b  of the main element  22  is also adjusted, then these adjustment is made so that the reception gain of the antenna of the present embodiment becomes a maximum. 
     A pattern of the glass antenna of the present embodiment is printed on the side glass  1  on a vehicle interior side with the conductive ceramic paste so that each line width is 0.5 mm, and after drying the pattern (after the pattern dries), the printed conductive ceramic paste is burned or baked in the heating furnace. Further, the AV line is fixed to the power feeding portion  21 , and the side glass  1  on which the pattern of the glass antenna is provided is mounted to the vehicle body. Furthermore, an outer sheath conductive line of the coaxial cable that extends from a tuner (not shown) is grounded or earthed at the ground point provided on the vehicle body in close proximity to the power feeding portion, while the core wire side of the coaxial cable is connected to the AV line. 
     When receiving the broadcast wave of the frequency 88 MHz˜108 MHz of the FM frequency band outside Japan by the glass antenna of the present embodiment formed in this way, as same as the glass antenna of the embodiment 1, a good reception performance can be obtained at the frequency band of the FM broadcast wave outside Japan. 
     In the glass antenna of the present embodiment, the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, whereas the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan. However, even if the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave outside Japan. 
     Further, in the glass antenna of the present embodiment, although the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave outside Japan, if the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave inside Japan, as same as the glass antenna of the present embodiment, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave inside Japan. 
     Furthermore, in the glass antenna of the present embodiment, the second line  222  of the main element  22  is arranged so as to extend along the center line e of the side glass  1 . Thus, the reception effective area for the AM broadcast wave can be increased, thereby also excellently receiving the AM broadcast wave by the glass antenna of the present embodiment. 
     Embodiment 4 
       FIG. 4  is a front view of a glass antenna according to an embodiment 4 of the present invention, when viewed from the vehicle exterior side. The glass antenna of the embodiment 4 is different from the glass antenna of the embodiment 3 in the respect that the power feeding portion  21  is disposed at a left side upper portion corner part of the side glass  1  and the first line  221  of the main element  22  is thus not bent along the left side of the side glass  1 , which does not form the second bending portion  221   b  of the first line  221 , and the top end of the square bracket-shaped element  23  is connected to some midpoint of the first line  221 . 
     With regard to the length of the main element  22  and the length obtained by adding the length from the power feeding portion  21  up to the connecting point between the main element  22  and the square bracket-shaped element  23  to the length of the square bracket-shaped element  23 , when the wavelength shortening coefficient (or the wavelength compaction ratio) α=0.7, and also when the wavelength of the center frequency 103 MHz of the frequency band which is higher than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ′ and the wavelength of the center frequency 93 MHz of the frequency band which is lower than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ, α·λ′·¾=1529 mm and α·λ·¾=1694 mm. The length of the main element  22  and the length obtained by adding the length from the power feeding portion  21  up to the connecting point between the main element  22  and the square bracket-shaped element  23  to the length of the square bracket-shaped element  23  are adjusted to become almost these lengths 1529 mm and 1694 mm respectively. 
     Further, in addition to the adjustment of the length of the main element  22  and the length obtained by adding the length from the power feeding portion  21  up to the connecting point between the main element  22  and the square bracket-shaped element  23  to the length of the square bracket-shaped element  23 , the length from the power feeding portion  21  up to the connecting point between the main element  22  and the square bracket-shaped element  23  is also adjusted, then these adjustment is made so that the reception gain of the antenna of the present embodiment becomes a maximum. 
     A pattern of the glass antenna of the present embodiment is printed on the side glass  1  on a vehicle interior side with the conductive ceramic paste so that each line width is 0.5 mm, and after drying the pattern (after the pattern dries), the printed conductive ceramic paste is burned or baked in the heating furnace. Further, the AV line is fixed to the power feeding portion  21 , and the side glass  1  on which the pattern of the glass antenna is provided is mounted to the vehicle body. Furthermore, an outer sheath conductive line of the coaxial cable that extends from a tuner (not shown) is grounded or earthed at the ground point provided on the vehicle body in close proximity to the power feeding portion, while the core wire side of the coaxial cable is connected to the AV line. 
     When receiving the broadcast wave of the frequency 88 MHz˜108 MHz of the FM frequency band outside Japan by the glass antenna of the present embodiment formed in this way, as same as the glass antenna of the embodiment 1, a good reception performance can be obtained at the frequency band of the FM broadcast wave outside Japan. 
     In the glass antenna of the present embodiment, the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, whereas the length obtained by adding the length from the power feeding portion  21  up to the connecting point between the main element  22  and the square bracket-shaped element  23  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan. However, even if the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan and the length obtained by adding the length from the power feeding portion  21  up to the connecting point between the main element  22  and the square bracket-shaped element  23  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave outside Japan. 
     Further, in the glass antenna of the present embodiment, although the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave outside Japan, if the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave inside Japan, as same as the glass antenna of the present embodiment, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave inside Japan. 
     Furthermore, in the glass antenna of the present embodiment, the second line  222  of the main element  22  is arranged so as to extend along the center line e of the side glass  1 . Thus, the reception effective area for the AM broadcast wave can be increased, thereby also excellently receiving the AM broadcast wave by the glass antenna of the present embodiment. 
     Embodiment 5 
       FIG. 5  is a front view of a glass antenna according to an embodiment 5 of the present invention, when viewed from the vehicle exterior side. The glass antenna of the embodiment 5 is different from the glass antenna of the embodiment 1 in the respect that a top end portion of the third line  223  of the main element  22  is bent to an inner side with respect to the third line  223 , which forms a bending portion  223   a  of the third line  223 , and the top end portion of the square bracket-shaped element  23  is turned back at an outer side of the square bracket-shaped element  23 , which forms the turning-back portion  23   a  of the square bracket-shaped element  23 , and two dummy elements  24  are provided. The reason why the top end portion of the third line  223  of the main element  22  is bent in this manner is because a size of the side glass  1  on which the glass antenna of the embodiment 5 is provided is smaller than the size of the side glass  1  on which the glass antenna of the embodiment 1 is provided. 
     With regard to the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , when the wavelength shortening coefficient (or the wavelength compaction ratio) α=0.7, and also when the wavelength of the center frequency 103 MHz of the frequency band which is higher than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ′ and the wavelength of the center frequency 93 MHz of the frequency band which is lower than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ, α·λ′·¾=1529 mm and α·λ·¾=1694 mm. The length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  are adjusted to become almost these lengths 1529 mm and 1694 mm respectively. 
     Further, in addition to the adjustment of the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , the length of the second bending portion  221   b  of the main element  22  is also adjusted, then these adjustment is made so that the reception gain of the antenna of the present embodiment becomes a maximum. 
     A pattern of the glass antenna of the present embodiment is printed on the side glass  1  on a vehicle interior side with the conductive ceramic paste so that each line width is 0.5 mm, and after drying the pattern (after the pattern dries), the printed conductive ceramic paste is burned or baked in the heating furnace. Further, the AV line is fixed to the power feeding portion  21 , and the side glass  1  on which the pattern of the glass antenna is provided is mounted to the vehicle body. Furthermore, an outer sheath conductive line of the coaxial cable that extends from a tuner (not shown) is grounded or earthed at the ground point provided on the vehicle body in close proximity to the power feeding portion, while the core wire side of the coaxial cable is connected to the AV line. 
     When receiving the broadcast wave of the frequency 88 MHz˜108 MHz of the FM frequency band outside Japan by the glass antenna of the present embodiment formed in this way, as same as the glass antenna of the embodiment 1, a good reception performance can be obtained at the frequency band of the FM broadcast wave outside Japan. 
     In the glass antenna of the present embodiment, the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, whereas the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan. However, even if the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave outside Japan. 
     Further, in the glass antenna of the present embodiment, although the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave outside Japan, if the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave inside Japan, as same as the glass antenna of the present embodiment, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave inside Japan. 
     Furthermore, in the glass antenna of the present embodiment, the second line  222  of the main element  22  is arranged so as to extend along the center line e of the side glass  1 . Thus, the reception effective area for the AM broadcast wave can be increased, thereby also excellently receiving the AM broadcast wave by the glass antenna of the present embodiment. 
     Embodiment 6 
       FIG. 6  is a front view of a glass antenna according to an embodiment 6 of the present invention, when viewed from the vehicle exterior side. The glass antenna of the embodiment 6 is different from the glass antenna of the embodiment 1 in the respect that the second line  222  of the main element  22  is greatly separate from the center line e of the side glass  1  and is shifted to the lower side of the side glass  1  as compared with the second line  222  of the embodiment 1. 
     With regard to the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , when the wavelength shortening coefficient (or the wavelength compaction ratio) α=0.7, and also when the wavelength of the center frequency 103 MHz of the frequency band which is higher than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ′ and the wavelength of the center frequency 93 MHz of the frequency band which is lower than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ, α·λ′·¾=1529 mm and α·λ·¾=1694 mm. The length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  are adjusted to become almost these lengths 1529 mm and 1694 mm respectively. 
     Further, in addition to the adjustment of the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , the length of the second bending portion  221   b  of the main element  22  is also adjusted, then these adjustment is made so that the reception gain of the antenna of the present embodiment becomes a maximum. 
     A pattern of the glass antenna of the present embodiment is printed on the side glass  1  on a vehicle interior side with the conductive ceramic paste so that each line width is 0.5 mm, and after drying the pattern (after the pattern dries), the printed conductive ceramic paste is burned or baked in the heating furnace. Further, the AV line is fixed to the power feeding portion  21 , and the side glass  1  on which the pattern of the glass antenna is provided is mounted to the vehicle body. Furthermore, an outer sheath conductive line of the coaxial cable that extends from a tuner (not shown) is grounded or earthed at the ground point provided on the vehicle body in close proximity to the power feeding portion, while the core wire side of the coaxial cable is connected to the AV line. 
     When receiving the broadcast wave of the frequency 88 MHz˜108 MHz of the FM frequency band outside Japan by the glass antenna of the present embodiment formed in this way, as same as the glass antenna of the embodiment 1, a good reception performance can be obtained at the frequency band of the FM broadcast wave outside Japan. 
     In the glass antenna of the present embodiment, the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, whereas the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan. However, even if the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave outside Japan. 
     Further, in the glass antenna of the present embodiment, although the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave outside Japan, if the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave inside Japan, as same as the glass antenna of the present embodiment, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave inside Japan. 
     In the glass antenna of the present embodiment, the second line  222  of the main element  22  is greatly separate from the center line e of the side glass  1  and is shifted to the lower side of the side glass  1  as compared with the second line  222  of the embodiment 1, then the second line  222  of the main element  22  is close to a part of the square bracket-shaped element  23  where the square bracket-shaped element  23  extends along the lower side of the side glass  1 . Thus, the reception effective area for the AM broadcast wave becomes small as compared with the glass antenna of the embodiment 1. Although the glass antenna of the present embodiment can adequately receive the AM broadcast wave, the glass antenna of the present embodiment can not receive the AM broadcast wave as excellently as the glass antenna of the embodiment 1 receives the AM broadcast wave. 
     Embodiment 7 
       FIG. 7  is a front view of a glass antenna according to an embodiment 7 of the present invention, when viewed from the vehicle exterior side. The glass antenna of the embodiment 7 is different from the glass antenna of the embodiment 1 in the respect that the second line  222  of the main element  22  is greatly separate from the center line e of the side glass  1  and is shifted to the upper side of the side glass  1  as compared with the second line  222  of the embodiment 1. 
     With regard to the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , when the wavelength shortening coefficient (or the wavelength compaction ratio) α=0.7, and also when the wavelength of the center frequency 103 MHz of the frequency band which is higher than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ′ and the wavelength of the center frequency 93 MHz of the frequency band which is lower than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ, α·λ′·¾=1529 mm and α·λ·¾=1694 mm. The length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  are adjusted to become almost these lengths 1529 mm and 1694 mm respectively. 
     Further, in addition to the adjustment of the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , the length of the second bending portion  221   b  of the main element  22  is also adjusted, then these adjustment is made so that the reception gain of the antenna of the present embodiment becomes a maximum. 
     A pattern of the glass antenna of the present embodiment is printed on the side glass  1  on a vehicle interior side with the conductive ceramic paste so that each line width is 0.5 mm, and after drying the pattern (after the pattern dries), the printed conductive ceramic paste is burned or baked in the heating furnace. Further, the AV line is fixed to the power feeding portion  21 , and the side glass  1  on which the pattern of the glass antenna is provided is mounted to the vehicle body. Furthermore, an outer sheath conductive line of the coaxial cable that extends from a tuner (not shown) is grounded or earthed at the ground point provided on the vehicle body in close proximity to the power feeding portion, while the core wire side of the coaxial cable is connected to the AV line. 
     When receiving the broadcast wave of the frequency 88 MHz˜108 MHz of the FM frequency band outside Japan by the glass antenna of the present embodiment formed in this way, as same as the glass antenna of the embodiment 1, a good reception performance can be obtained at the frequency band of the FM broadcast wave outside Japan. 
     In the glass antenna of the present embodiment, the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, whereas the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan. However, even if the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave outside Japan. 
     Further, in the glass antenna of the present embodiment, although the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave outside Japan, if the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave inside Japan, as same as the glass antenna of the present embodiment, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave inside Japan. 
     In the glass antenna of the present embodiment, the second line  222  of the main element  22  is greatly separate from the center line e of the side glass  1  and is shifted to the upper side of the side glass  1  as compared with the second line  222  of the embodiment 1, then the second line  222  of the main element  22  is close to a part of the first line  221  of the main element  22  where the first line  221  of the main element  22  extends along the upper side of the side glass  1 . Thus, the reception effective area for the AM broadcast wave becomes small as compared with the glass antenna of the embodiment 1. Although the glass antenna of the present embodiment can adequately receive the AM broadcast wave, the glass antenna of the present embodiment can not receive the AM broadcast wave as excellently as the glass antenna of the embodiment 1 receives the AM broadcast wave. 
     Embodiment 8 
       FIG. 8  is a front view of a glass antenna according to an embodiment 8 of the present invention, when viewed from the vehicle exterior side. The glass antenna of the embodiment 8 is an antenna that is obtained by arranging each element of the glass antenna of the embodiment 1 to be symmetrical about a center point of the side glass  1 . 
     With regard to the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , when the wavelength shortening coefficient (or the wavelength compaction ratio) α=0.7, and also when the wavelength of the center frequency 103 MHz of the frequency band which is higher than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ′ and the wavelength of the center frequency 93 MHz of the frequency band which is lower than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ, α·λ′·¾=1529 mm and α·λ·¾=1694 mm. The length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  are adjusted to become almost these lengths 1529 mm and 1694 mm respectively. 
     Further, in addition to the adjustment of the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , the length of the second bending portion  221   b  of the main element  22  is also adjusted, then these adjustment is made so that the reception gain of the antenna of the present embodiment becomes a maximum. 
     A pattern of the glass antenna of the present embodiment is printed on the side glass  1  on a vehicle interior side with the conductive ceramic paste so that each line width is 0.5 mm, and after drying the pattern (after the pattern dries), the printed conductive ceramic paste is burned or baked in the heating furnace. Further, the AV line is fixed to the power feeding portion  21 , and the side glass  1  on which the pattern of the glass antenna is provided is mounted to the vehicle body. Furthermore, an outer sheath conductive line of the coaxial cable that extends from a tuner (not shown) is grounded or earthed at the ground point provided on the vehicle body in close proximity to the power feeding portion, while the core wire side of the coaxial cable is connected to the AV line. 
     When receiving the broadcast wave of the frequency 88 MHz˜108 MHz of the FM frequency band outside Japan by the glass antenna of the present embodiment formed in this way, as same as the glass antenna of the embodiment 1, a good reception performance can be obtained at the frequency band of the FM broadcast wave outside Japan. 
     In the glass antenna of the present embodiment, the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, whereas the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan. However, even if the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave outside Japan. 
     Further, in the glass antenna of the present embodiment, although the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave outside Japan, if the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave inside Japan, as same as the glass antenna of the present embodiment, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave inside Japan. 
     Furthermore, in the glass antenna of the present embodiment, the second line  222  of the main element  22  is arranged so as to extend along the center line e of the side glass  1 . Thus, the reception effective area for the AM broadcast wave can be increased, thereby also excellently receiving the AM broadcast wave by the glass antenna of the present embodiment. 
     Embodiment 9 
       FIG. 9  is a front view of a glass antenna according to an embodiment 9 of the present invention, when viewed from the vehicle exterior side. The glass antenna of the embodiment 9 is an antenna that is obtained by arranging each element of the glass antenna of the embodiment 8 to be symmetrical about the center line e of the side glass  1 . 
     With regard to the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , when the wavelength shortening coefficient (or the wavelength compaction ratio) α=0.7, and also when the wavelength of the center frequency 103 MHz of the frequency band which is higher than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ′ and the wavelength of the center frequency 93 MHz of the frequency band which is lower than the center frequency of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan is λ, α·λ′·¾=1529 mm and α·λ·¾=1694 mm. The length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  are adjusted to become almost these lengths 1529 mm and 1694 mm respectively. 
     Further, in addition to the adjustment of the length of the main element  22  and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23 , the length of the second bending portion  221   b  of the main element  22  is also adjusted, then these adjustment is made so that the reception gain of the antenna of the present embodiment becomes a maximum. 
     A pattern of the glass antenna of the present embodiment is printed on the side glass  1  on a vehicle interior side with the conductive ceramic paste so that each line width is 0.5 mm, and after drying the pattern (after the pattern dries), the printed conductive ceramic paste is burned or baked in the heating furnace. Further, the AV line is fixed to the power feeding portion  21 , and the side glass  1  on which the pattern of the glass antenna is provided is mounted to the vehicle body. Furthermore, an outer sheath conductive line of the coaxial cable that extends from a tuner (not shown) is grounded or earthed at the ground point provided on the vehicle body in close proximity to the power feeding portion, while the core wire side of the coaxial cable is connected to the AV line. 
     When receiving the broadcast wave of the frequency 88 MHz˜108 MHz of the FM frequency band outside Japan by the glass antenna of the present embodiment formed in this way, as same as the glass antenna of the embodiment 1, a good reception performance can be obtained at the frequency band of the FM broadcast wave outside Japan. 
     In the glass antenna of the present embodiment, the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, whereas the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan. However, even if the length of the main element  22  is adjusted in accordance with the center frequency of the frequency band which is lower than the center frequency of the frequency band of the FM broadcast wave outside Japan and the length obtained by adding the length of the second bending portion  221   b  of the main element  22  to the length of the square bracket-shaped element  23  is adjusted in accordance with the center frequency of the frequency band which is higher than the center frequency of the frequency band of the FM broadcast wave outside Japan, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave outside Japan. 
     Further, in the glass antenna of the present embodiment, although the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave outside Japan, if the connecting point of the square bracket-shaped element  23  with the main element  22  and the length of each element are adjusted so that the reception gain becomes a maximum at the frequency band of the FM broadcast wave inside Japan, as same as the glass antenna of the present embodiment, the excellent reception of the FM broadcast wave can be possible at the frequency band of the FM broadcast wave inside Japan. 
     Furthermore, in the glass antenna of the present embodiment, the second line  222  of the main element  22  is arranged so as to extend along the center line e of the side glass  1 . Thus, the reception effective area for the AM broadcast wave can be increased, thereby also excellently receiving the AM broadcast wave by the glass antenna of the present embodiment. 
     Although the present invention has been described above by reference to certain embodiments of the invention, the present invention is not limited to the embodiments described above. Modifications and variations of the embodiments described above can be possible as the present invention. 
     Comparative Example 
       FIG. 10  is a front view of a glass antenna according to the comparative example of the present invention, when viewed from the vehicle exterior side. A glass antenna  2  of the comparative example has only the power feeding portion  21  and the main element  22  on the side glass  1  that is mounted on or fitted into the side flange of the vehicle. The glass antenna  2  of the comparative example is a well-known FM frequency band glass antenna provided on the side glass. 
     The power feeding portion  21  is provided at the left side portion of the side glass  1 . One end of the main element  22  is connected to the power feeding portion  21 , and the other end of the main element  22  is open. 
     The main element  22  is formed into an inverted S-shape, and has the first line  221 , the second line  222  and the third line  223 . 
     The first line  221  is arranged at the upper side of the side glass  1 , and left and right end portions of the first line  221  are bent. The first bending portion  221   a  of the first line  221 , which is disposed so as to extend along a right side of the side glass  1 , and the second bending portion  221   b  of the first line  221 , which is disposed so as to extend along a left side of the side glass  1 , are formed on the side glass  1 . The top end of the first bending portion  221   a  of the first line  221  is connected to one end of the second line  222 , and the top end of the second bending portion  221   b  of the first line  221  is connected to the power feeding portion  21 . 
     The second line  222  is a line that is parallel to the upper side of the side glass  1  and is positioned and extends in close proximity to a center line e of the side glass  1  and also reaches up to both left and right sides of the side glass  1 . The one end of the second line  222  is connected to the top end of the first bending portion  221   a  of the first line  221 , and another one end (the other end) of the second line  222  is connected to the top end of the third line  223 . 
     The third line  223  is arranged so as to extend along the left side of the side glass  1 . One end of the third line  223  is connected to the top end of the second line  222 , and the third line  223  is elongated in a direction moving away from the power feeding portion  21 . Another one end (the other end) of the third line  223  is bent, and forms the bending portion  223   a  of the third line  223 . 
     &lt;Measurement Result when Adjusting Configuration of Antenna of Comparative Example in Accordance with Frequency Band of FM Broadcast Wave Outside Japan&gt; 
     When adjusting a configuration of the glass antenna  2  of the comparative example to properly receive the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan, each size is as follows.
     a lateral width a of flange=672 mm   a longitudinal width b of flange=414 mm   a length of main element  22 =2234 mm   a length of first bending portion  221   a  of main element  22 =200 mm   a length of second bending portion  221   b  of main element  22 =86 mm   a length of second line  222  of main element  22 =610 mm   a length of third line  223  of main element  22 =757 mm   a length of bending portion  223   a  of third line  223  of main element  22 =170 mm   a clearance c″ between main element  22  and flange peripheral edge  3 =10 mm   

     A pattern of the glass antenna of the present embodiment is printed on the side glass  1  on a vehicle interior side with the conductive ceramic paste so that each line width is 0.5 mm, and after drying the pattern (after the pattern dries), the printed conductive ceramic paste is burned or baked in the heating furnace. Further, the AV line is fixed to the power feeding portion  21 , and the side glass  1  on which the pattern of the glass antenna is provided is mounted to the vehicle body. Furthermore, an outer sheath conductive line of the coaxial cable that extends from a tuner (not shown) is grounded or earthed at the ground point provided on the vehicle body in close proximity to the power feeding portion, while the core wire side of the coaxial cable is connected to the AV line. 
     When receiving the broadcast wave of the frequency 76 MHz˜108 MHz of the FM frequency band inside and outside Japan by the glass antenna of the comparative example formed in this way, the result shown in  FIG. 11  was obtained. 
       FIG. 11  is the measurement result of the glass antenna  2  of the comparative example and the glass antenna  2  of the embodiment 1, and shows the reception gain at each frequency of 76 MHz˜108 MHz. Here, the reception gain indicates an average of a reception gain obtained at each angle in all directions. In  FIG. 11 , the solid line indicates the measurement result of the glass antenna  2  of the embodiment 1, and the broken line indicates the measurement result of the comparative example. 
     From  FIG. 11 , with respect to the glass antenna of the embodiment 1, a high reception gain can be obtained over the full range of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan. However, as for the glass antenna of the comparative example, a high reception gain can be obtained only at 92 MHz, and a high reception gain can not be obtained over the full range of the frequency band (88 MHz˜108 MHz) of the FM broadcast wave outside Japan. 
     Reference Example 
       FIGS. 12A and 12B  are reference examples for explaining the reception effective area of the glass antenna for AM broadcast wave. In  FIG. 12A , the second line  222  of the main element  22 , which forms the glass antenna  2 , is arranged so as to extend along the center line e of the side glass  1 . In  FIG. 12B , the second line  222  of the main element  22  is arranged in close proximity to the bending portion  223   a  of the third line  223 . 
     As shown by the circle drawn by the dotted line which encircles each line, which forms the glass antenna  2 , in  FIGS. 12A and 12B , each line forming the glass antenna  2  has a certain reception effective area. Therefore, when the lines forming the glass antenna  2  are arranged so that the reception effective area of each line does not overlap with each other as shown in  FIG. 12A , the glass antenna  2  can have a great reception effective area for the AM broadcast wave, as compared with the case in which the lines are arranged close to each other like the second line  222  of the main element  22  and the bending portion  223   a  of the third line  223  as shown in  FIG. 12B . 
     EXPLANATION OF REFERENCE 
     
         
           1  . . . side glass 
           2  . . . glass antenna 
           21  . . . power feeding portion 
           22  . . . main element 
           221  . . . first line 
           221   a  . . . first bending portion of first line 
           221   b  . . . second bending portion of first line 
           221   c  . . . bending point of second bending portion of first line 
           222  . . . second line 
           223  . . . third line 
           223   a  . . . bending portion of third line 
           23  . . . square bracket-shaped element 
           23   a  . . . turning-back portion of square bracket-shaped element 
           24  . . . dummy element 
           3  . . . flange peripheral edge 
         a . . . lateral width of flange 
         b . . . longitudinal width of flange 
         c . . . clearance between square bracket-shaped element and flange peripheral edge 
         c′ . . . clearance between second bending portion of main element and flange peripheral edge, and clearance between third line of main element and flange peripheral edge 
         c″ . . . clearance between main element and flange peripheral edge in comparative example 
         d . . . distance between main element and square bracket-shaped element 
         d′ . . . distance between dummy element and square bracket-shaped element 
         e . . . center line of side glass