JP4610444B2 - Vehicle antenna - Google Patents

Description

  The present invention is an antenna of a conductive wire disposed on a window glass surface of a moving body such as an automobile or the surface of an insulating member of a body or inside thereof, and receives a radio wave of a television UHF broadcast wave or a VHF broadcast wave. The present invention relates to an antenna suitable for transmission / reception of a wideband radio wave such as a car phone, a mobile phone, a personal radio, a business radio, and a PHS.

  Conventionally, pole antennas have been put into practical use and widely used as antennas for transmission / reception of automobile phones and mobile phones, and for reception of television broadcast waves, but these pole antennas have a structure protruding from the vehicle body. Therefore, it is not only unfavorable in terms of safety and appearance, but also has drawbacks such as a hindrance during car washing and a possibility of breakage.

  Therefore, in recent years, as antennas without protrusions, there are glass antennas that are provided by directly printing antenna patterns on automobile window glass, and antennas that have antenna patterns printed on stickers or sheets attached to window glass or resin bodies. It has been requested and put into practical use.

  Glass antennas and seal antennas that have been put to practical use as antennas for automobile phones and mobile phones have been put into practical use that have a transmission / reception gain that is equivalent to that of a pole antenna.

  For example, Japanese Patent Laid-Open No. 3-108903 discloses a loop-shaped antenna conductor formed on an insulating surface of an automotive window glass and a non-loop-shaped antenna conductor connected in parallel to a feeding point of the loop-shaped antenna conductor. And the non-loop antenna conductor has a resonance frequency in a frequency range excluding the vicinity of an integral multiple of the natural resonance frequency of the loop antenna conductor. Reference 1).

  Japanese Laid-Open Patent Publication No. 6-152216 discloses a radiation pattern having a length of about 1/4 wavelength in the vertical direction on the glass surface and a ground pattern having a length of about 1/4 wavelength in the horizontal direction on the glass surface. When the grounding pattern is provided on at least one of the left and right ends of the glass surface, and the grounding pattern is provided on the left end, the radiation pattern is disposed near the left side of the grounding pattern, and the grounding pattern is disposed on the right end. A glass antenna for an automobile telephone is disclosed in which a radiation pattern is disposed close to the right side of a grounding pattern when the grounding pattern is provided, and the grounding pattern has a hollow shape (Patent Document 2). ).

  Further, Japanese Patent Laid-Open No. 9-93019 discloses that a capacitive coupling portion is provided in the middle of each loop so that the middle of each loop in the VHF double loop antenna pattern portion is short-circuited in high frequency. In reception, the loops are short-circuited in the middle through the capacitive coupling units, and the VHF dual-loop antenna pattern unit functions as a UHF dual-loop antenna pattern unit. A window glass antenna is described (Patent Document 3).

Furthermore, the antenna handbook (issued by CQ Publishing Co., Ltd.) describes a cubic quad antenna as a loop antenna having a total circumference of one wavelength between two feeding points (Non-Patent Document 1).
Japanese Patent Laid-Open No. 3-108903 JP-A-6-152216 JP-A-9-93019 Antenna Handbook 24th edition (issued on May 15, 2002) CQ Publishing Co., Ltd. 354 pages

  However, the antenna disclosed in Patent Document 1 is a loop antenna that surrounds the defogger of the rear window glass, and even a loop antenna can cover a wide band such as an FM broadcast wave to a TV broadcast wave with one antenna. Since it is not a wide band, even if a dipole antenna is additionally provided from the same feeding point so that it can receive radio waves of TV broadcast waves, the dipole antenna is not wide band and cannot cover the entire TV broadcast waves. was there.

  In addition, the antenna shown in Patent Document 2 is a glass antenna for a car phone, and is arranged on the outside of the ground pattern, connected to the ground side of the coaxial cable, and arranged on the core wire side. Two independent elements of the radiation pattern connected to the glass are provided on the left and right edges of the glass. The gain is lower than that of the pole antenna, and further improvement of the antenna gain is desired. There is a problem that it can only be provided.

  Further, the antenna shown in Patent Document 3 is a glass antenna having a double loop antenna pattern part capable of receiving radio waves in the VHF band and UHF band of TV broadcast waves, and is high in the UHF band of TV broadcast waves. Other than the above, the VSWR value is high and the frequency band is narrow, so the entire UHF band cannot be covered. When trying to cover the entire UHF band, a separate antenna must be provided. There is a problem that the antenna can be disposed only in a limited space.

  Furthermore, the cubic quad antenna described in Non-Patent Document 1 provides excellent transmission / reception performance at that frequency when a single-wavelength loop antenna is used, but the frequency band is narrow and television broadcasting is used. When transmitting and receiving broadband radio waves such as receiving UHF broadcast waves (470 to 770 MHz band) and VHF broadcast waves, separate antennas have to be provided.

  The present invention has been made in view of such problems, and is an antenna of conductive wires disposed on a window glass surface of a moving body such as an automobile or on an insulating member surface of a body, Suitable for transmitting and receiving radio waves from antennas for mobile phones, receiving antennas for television UHF broadcast waves and VHF broadcast waves, and for broadband radio waves up to personal radio, commercial radio, and PHS. An object of the present invention is to provide a vehicular antenna that can improve the antenna performance more than ever and is less likely to be caught by the position on the surface of the window glass on which the antenna is disposed or the surface of the insulating member of the body.

That is, the present invention is an antenna composed of a conductive wire disposed on a window glass surface of a moving body such as an automobile or an insulating member surface of a body, and the first feeding point and the second feeding point are provided close to each other. A loop element having a length of 1 to 2 wavelengths of transmission / reception radio waves in which conductive filaments are arranged from the first feeding point to the second feeding point, and either the feeding point or the feeding point A first element for adjusting impedance having a length of ¼ wavelength to ¾ wavelength of a transmission / reception radio wave branched and extended to the inside of the loop element via a lead wire, and a loop element from the middle of the loop element The vehicle antenna is characterized in that it is a loop antenna comprising a second element having a length of 1/16 to 1/4 wavelength branched and extended outward.

  Alternatively, according to the present invention, the first element and the proximity of the line of the loop element extended from a feeding point side that is substantially parallel to the first element and that is different from the feeding point to which the first element is connected. The above-described vehicle antenna is characterized in that the distance from the line portion to be made is 0.1 mm to ¼ wavelength, and the length is 1/8 wavelength to ¾ wavelength.

  Alternatively, in the present invention, a second element having a length of 1/16 to 1/4 wavelength extending from the one of the feeding points to the outer side of the loop element is further provided. The vehicle antenna according to any one of the above-described features.

  Alternatively, the present invention is characterized in that the antenna pattern is directly formed on or in the surface made of an insulating member of a window glass or body of a moving body such as an automobile, or a transparent seal or sheet on which the pattern is printed is pasted. The vehicle antenna according to any one of the above.

  According to the present invention, a loop element having a length of 1 to 2 wavelengths of transmission / reception radio waves is provided to be branched from a feeding point of the loop element or from the feeding point to the inside of the loop element via a lead line. A first element having a length of ¼ wavelength to ¾ wavelength, and a branch extending from one of the feeding points to the outside of the loop element from a middle portion of the line of the loop element. By providing a second element having a length of 16 to ¼ wavelength, it is used for transmitting and receiving radio waves from antennas for car phones and mobile phones, and receiving radio waves from television UHF and VHF broadcast waves. This antenna is suitable for transmission / reception of wideband radio waves up to personal antennas, commercial radios, and PHS, and can improve the antenna performance more than before.

  Furthermore, the present invention is not easily caught by the position of the window glass surface on which the antenna is disposed or the insulating member of the body, and has a simple configuration, so that the antenna can be made compact and have a high performance.

  Furthermore, not only as a glass antenna that prints directly on the inner surface of a vehicle window glass, but also on a window glass surface, the surface of an insulating member of the body, or inside, a thin sticker or a sheet printed on a sheet. Since it can be a seal antenna, it is easy to mount.

  The present invention provides an antenna for a car phone, a mobile phone, a TV broadcast wave VHF band, and an antenna for receiving a UHF band on the inner surface side of a window glass 1 of a moving body such as an automobile, or on the front and back surfaces or inside of an insulating member of a body Further, a transparent seal or sheet on which an antenna pattern of an antenna conductive wire that can transmit and receive broadband radio waves such as a car phone, a mobile phone, a personal radio, a commercial radio, and a PHS is directly formed or printed. It is the antenna for vehicles which stuck.

  In FIG. 1, the pattern of the vehicle antenna of this invention is shown.

  In the antenna pattern, the first feeding point 10 and the second feeding point 11 are provided close to each other, and transmission / reception is performed between the first feeding point 10 and the second feeding point 11 in a loop shape such as a rectangle or a circle. A loop element 3 having a length of 1 to 2 wavelengths of radio waves is formed, and a quarter wavelength to 3/4 wavelengths of transmitted / received radio waves are provided inside the loop element 3 from one of the feeding points 10 and 11. The first element 4 having a length of 1 mm is directly extended, and the second element 5 having a length of 1/16 to 1/4 wavelength is branched from the middle portion of the line of the loop element 3 to the outside of the loop element 3. Thus, the internal conductor 12a of the coaxial cable 12 is connected to one of the first feeding point 10 and the second feeding point 11, and the external conductor 12b is connected to the other feeding point. .

  As shown in FIGS. 1 to 5, the first element 4 is represented by a short dotted line and the second element 5 is represented by a long dotted line. Is not a broken line, but a continuous filament.

  The pattern shown in FIG. 2 is obtained by modifying the pattern shown in FIG. 1 and extending two lead wires 7 from the first feeding point 10 and the second feeding point 11 of the loop element 3. The two feeding points 10 and 11 to the loop element 3 are arranged in parallel and close to each other with a length of ½ wavelength or less.

That is, each of the first feeding point 10 and the second feeding point 11 is connected to the loop element 3 via the lead wire 7, and the other configuration is the same as that shown in FIG.
The pattern shown in FIG. 3 is another modification of the pattern shown in FIG. 1 and is used as an antenna for a cellular phone band. The loop element 3 has a substantially rectangular shape. The auxiliary vertical filaments 6 are additionally provided inside, and the others are the same as in FIG. In addition, although the said auxiliary | assistant perpendicular | vertical filament 6 was represented by the dashed-dotted line, this filament is not what interrupted, but is a continuous filament.

  In the pattern shown in FIG. 4, the feeding point is arranged through the lead wire 7 in the outer horizontal direction from the corner of the lower side of the rectangular loop element 3, and the first element 4 is placed inside the lower side of the loop element 3. It is provided in the vicinity and has an L shape bent upward from the vicinity of the center of the lower side of the loop element 3.

  The pattern shown in FIG. 5 is a modification of the pattern of FIG. 4, in which a feeding point is provided at the corner of the rectangular loop antenna, and the first element 4 is placed inside the rectangular lower side and side of the loop element 3. In addition to the second element 5 branched from the middle part of the loop element 3, a second element 5 ′ is provided close to the outside of the loop element 3 from the feeding point. is there.

  Further, the distance a between the filament of the first element 4 and the portion of the filament of the loop element 3 provided substantially parallel to the filament of the first element 4 is closest. The part is 0.1 mm, and the farthest part is a quarter wavelength of the transmission / reception frequency.

  Furthermore, the line width of the loop element 3, the first element 4, and the second element 5 is set to 0.1 mm to 1/16 wavelength of the transmission / reception frequency so as not to obstruct the field of view as viewed from inside the vehicle. In addition, it goes without saying that the adjacent stripes do not overlap each other.

  Such an antenna pattern is directly printed on a surface made of a window glass of a moving body such as an automobile or an insulating member of a body, or is sandwiched between laminated glass glasses, or a transparent seal or sheet on which the antenna pattern is printed is pasted. Set up.

  The body insulating member means that a thin film antenna is attached to the inside of a resin bumper of an automobile, the inside of a resin spoiler, or the inside surface of a resin hatch back door, or these resin parts Other than the terminal portion is integrally formed at the time of molding.

  The transparent seal or sheet is one in which an antenna pattern is printed on a transparent and thin resin sheet such as polyethylene or a film-like sheet, or conductive lines are provided by etching or the like.

  As shown in FIGS. 1 to 3, the first element 4 is provided from one of the feeding points 10 and 11, or from the feeding points 10 and 11 via a lead wire, If the first element 4 having a length of ¼ wavelength to ¾ wavelength of the transmitted / received radio wave is extended on the inner side, it is bent in the perpendicular direction in the middle as shown in the first element 4 of FIG. However, even in this case, it is close to the line of the loop element 3 that is closest to the first element 4 in parallel with a length of 1/8 wavelength to 3/4 wavelength. Furthermore, it is preferable that the distance a between the first element 4 and the adjacent loop element 3 is within a quarter wavelength.

  Alternatively, as shown in the pattern of FIG. 5, each of the horizontal and vertical line portions of the first element may be extended along the loop element 3.

  Further, as shown in the pattern 5 of FIG. 5, a second element 5 ′ may be provided along the outside of the loop element 3 from the second feeding point 11 separately from the second element 5. good.

  As shown in FIGS. 1 to 5, the second element 5 branches from either one of the feeding points or from a middle portion of the line of the loop element 3 and horizontally extends to the outside of the loop element 3. Although the strip extends in the direction, the direction is not limited to the horizontal direction and may be any direction.

  Further, since the second element 5 needs to be provided at a position that does not hinder the resonance of the loop antenna 2, the branch point from the loop element 3 and the feeding point of the second element 5 are on the loop element 3. It is better not to provide it in the vicinity of the positions facing each other. That is, it is better not to branch from a position where the length from the two feeding points is about ± 10% of the position of about 1/2 of the total length of the loop element including the lead wire 7.

  In the first element 4, the direction extending from the branch point with respect to the loop element or the feeding point may be any of a vertical direction, a horizontal direction, and an oblique direction, and a bent crank shape, a key shape, or an arc shape. It can also be a shape.

  As the window glass of the automobile and the like, it may be provided on any of the window glass of the front window glass, rear window glass, side window glass, sunroof, etc. of the automobile, and the window glass is not only a glass plate, A case of a transparent resin plate or a composite of a glass plate and a transparent resin plate is also included.

  Also, the body of the moving body is usually made of metal, but when the roof, the rear door, and some other members are made of an insulating member such as a resin, or the insulating member made of a resin such as a bumper or a spoiler In such an insulating member, the loop antenna 2 of the present invention can be provided.

  Further, the loop antenna 2 is formed by directly printing the antenna pattern with a conductive paste on the surface of a member made of an insulating material of a window glass 1 or a body of a moving body such as an automobile, or embedding a conductive material. The printed seal or sheet may be attached to a part made of these insulating materials.

  Moreover, although the said loop antenna 2 may be provided only in one place, diversity reception can be enabled by providing in multiple places. In this case, the same pattern or different patterns may be used. The shape of the loop element 3 is a square shape or a rectangular shape, but may be a circular shape, an elliptical shape, or a polygonal shape.

  The operation of the present invention will be described below.

  The reason why the loop element 3 has a loop shape of 1 to 2 wavelengths of transmission / reception radio waves is to resonate the loop antenna 2, and a length of 1/2 to 2 wavelengths of transmission / reception radio waves is suitable for the loop element 3. ing.

  This is because the loop antenna 2 of the present invention resonates with the loop element 3 and the first element 4 is provided inside the loop element 3, whereby the transmission / reception efficiency of the antenna of the loop antenna 2 can be further increased. In order to provide the first element 4 inside the element 3, the length of the loop element 3 is required to be one wavelength or longer, and the length of the loop element 3 is a loop shape of one to two wavelengths of transmission / reception radio waves. Is optimal.

  In addition, the first element 4 is a line having a length of ¼ wavelength to ¾ wavelength of the transmission / reception radio wave, and is provided from the middle of the loop element 3 toward the inner side. This is because the transmission / reception efficiency can be further increased, so that radio waves can be transmitted / received from the first element 4 in addition to the loop element 3, and the transmission / reception efficiency of the antenna can be further improved as compared with the loop antenna.

  Furthermore, the length of the second element 5 is set to 1/16 wavelength to 1/4 wavelength, and it is provided outside by branching from the middle part of the loop element 3 to improve the antenna efficiency of the loop antenna 2 and to increase the antenna efficiency. The second element 5 having a length of 1/16 wavelength to 1/4 wavelength is added to the loop element 3 of 1 wavelength to 2 wavelengths of transmission / reception radio waves, so that the original loop antenna can be obtained. In addition to the resonance mode, the antenna also resonates with the total length of the loop element 3 and the second element 5.

  Since the transmission / reception radio wave that resonates at the total element length has a lower frequency than the transmission / reception radio wave used in the second element 5, adding the second element 5 increases the bandwidth of the antenna. This is because transmission / reception efficiency can be improved.

  The length of the loop element 3 and the first element 4 adjacent to the filaments is set to 1/8 wavelength to 3/4 wavelength in order to adjust the impedance of the antenna. The antenna element length longer than the wavelength is necessary, but the length of the first element 4 is ¼ wavelength to ¾ wavelength, and the length of ８ wavelength to ¾ wavelength is the first. The antenna impedance can be adjusted by bringing the element 4 and the loop element 3 close to each other.

  In addition, the distance a between the loop element 3 and the first element 4 and the adjacent line a is set to 0.1 mm to ¼ wavelength. The first element 4 performs antenna transmission / reception and impedance adjustment. When the loop element 3 and the first element 4 are separated from each other by a quarter wavelength for efficient transmission and reception, and when the impedance is adjusted by making them close to each other at an interval a of ¼ wavelength or less. The selection may be made as appropriate.

  Further, when the lengths of the loop elements 3 and the first element 4 are selected for the same frequency with respect to the frequency to be transmitted and received, a very high gain is obtained with respect to the selected frequency. A high-gain antenna can be obtained over a wide band of frequencies between the frequency that resonates to the length obtained by adding the second elements 5 and 5 ′ to the element 3 and the loop element 3, and the frequencies around the frequency.

  On the other hand, by selecting the length of each line of the loop element 3 and the first element 4 for different frequencies, the second element 5 is added to the selected frequency, the loop element 3 and the loop arrangement 3. It is possible to obtain a high gain antenna between frequencies that resonate with the added length and over a wider band than frequencies before and after the frequency.

  Further, since the second element 5 needs to be provided at a position that does not hinder the resonance of the loop antenna 2, the branch point from the loop element 3 and the feeding point of the second element 5 are on the loop element 3. It is better not to provide it in the vicinity of the positions facing each other. That is, it is better not to branch from a position where the length from the two feeding points is about ± 10% of the position of about 1/2 of the total length of the loop element including the lead wire 7.

  Various embodiments of the present invention will be described below.

  FIG. 11 is a view of the loop antenna 2 of the present invention shown in FIGS. 1 to 5 as viewed from the outside of the vehicle provided at the upper corners of the front window glass 1 of the automobile. Two places are provided so that the two loop antennas 2 and 2 receive diversity, and the patterns of FIGS. 1 to 5 are turned upside down so that the first feeding point 10 and the second feeding point 11 are provided. Is arranged on the peripheral side of the window glass 1, and the left and right patterns are symmetrical with respect to the center line of the glass plate.

[Example 1]
In the pattern shown in FIG. 1, the loop antenna 2 composed of the loop element 3, the first element 4, and the second element 5 is printed on the inner surface of the vehicle window glass plate after being printed, or the pattern is transparently sealed. Or what was printed on the sheet | seat is affixed on the surface of insulation members, such as a vehicle body, and is used as an antenna of the TV broadcast wave UHF band of a frequency band 470-770 MHz band.

  The first feeding point 10 and the second feeding point 11 are provided close to each other at an interval of 2 mm, and the substantially square loop element 3 is provided between the first feeding point 10 and the second feeding point 11. The first feeding point 10 and the second feeding point 11 are disposed at the center position of the lower side of the square shape of the loop element 3.

  In addition, the first element 4 was formed by extending a vertical line corresponding to the length of a quarter wavelength of transmitted / received radio waves in the vertical direction above the first feeding point 10.

  Further, a horizontal line corresponding to the length of 1/8 wavelength of the transmitted / received radio wave is extended in the horizontal direction from the left corner of the lower side of the substantially square loop element 3 to form a second element 5.

  The loop antenna 2 is provided directly on the indoor side of the window glass plate surface of an automobile, or pasted on a sticker or sheet, and is provided with a wavelength reduction rate of the window glass 1 in a frequency band of 470 to 770 MHz. Is about 0.6 mm, the length of the entire circumference of the loop element 3 is 400 mm corresponding to a wavelength of about 3/2 with respect to a frequency of 660 MHz. The length of 5 is a length of 35 mm corresponding to a length of about 1/8 wavelength, and the length of the first element 4 is a length of 78 mm corresponding to a length of about 1/4 wavelength for a frequency of 570 MHz. did.

  Further, an internal conductor 12 a of a coaxial cable 12 having a characteristic impedance of 75 ohms was connected to the first feeding point 10, and an external conductor 12 b was connected to the second feeding point 11.

  The antenna 2 in which the first element 4 and the second element 5 are arranged as described above was adjusted so that the reception gain in the UHF band of the TV broadcast wave in the 470 to 770 MHz band was increased.

  The VSWR characteristic of the antenna of FIG. 1 arranged in this way is as low as 1.5 or less over the entire TV broadcast wave UHF band (470 to 770 MHz) as shown in FIG. 10), it can be seen that the VSWR is low over the entire range of the TV broadcast wave UHF band, and it can be covered over a wide band.

  Further, when the gain of the dipole antenna is set to 0 dB for the antenna of FIG. 1 obtained in this way (hereinafter abbreviated as a dipole antenna ratio), it is as shown in the frequency characteristic diagram of FIG. In addition, the average of the 470 to 770 MHz band was −8.9 dB, and a good result exceeding the transmission / reception gain of −20.0 dB, which is the average of conventional glass antennas used in practical use, was obtained.

Thus, it can be seen that an antenna that does not impair the field of view despite having a simple configuration can be provided, and that the gain is high enough to be practically used.
[Example 2]
The antenna shown in FIG. 2 is a modification of the pattern of the first embodiment, and is connected to the square loop element 3 from the first feeding point 10 and the second feeding point 11 via the lead wire 7. The other configurations and the lengths of the filaments are the same as those of the first embodiment shown in FIG. 1, and the loop antenna 2 of the present invention is disposed on the inner surface of the glass surface.

  Moreover, the length of the lead wire 7 extended upward from each of the 1st feed point 10 and the 2nd feed point 11 was 30 mm, and the space | interval of the lead wire 7 was 2 mm.

  The VSWR characteristics in the entire TV broadcast wave UHF band (470 to 770 MHz) of the antenna shown in FIG. 2 thus obtained are as low as 1.5 or less as in the first embodiment, and cover the entire TV broadcast wave UHF band. It was possible.

  Further, when the gain of the dipole antenna is set to 0 dB for the antenna of FIG. 2 arranged in this way (hereinafter abbreviated as a dipole antenna ratio), it is −9. The gain was equal to 0 dB and the same gain as in Example 1 was obtained, and a good result exceeding the transmission / reception gain of −20.0 dB, which is the average of conventional glass antennas put to practical use, was obtained.

Thus, it can be seen that an antenna that does not impair the field of view despite having a simple configuration can be provided, and that the gain is high enough to be practically used.
[Example 3]
The pattern shown in FIG. 3 is another modification of the pattern of the first embodiment, and is used as an antenna for a cellular phone band in the frequency band 800 to 960 MHz. The first feeding point 10 and the second feeding point 11 are provided close to each other at an interval of 2 mm, and the substantially rectangular loop element 3 is provided between the first feeding point 10 and the second feeding point 11.

  Further, when the wavelength shortening rate of the window glass 1 in the frequency band of 800 to 960 MHz is about 0.6, the entire length of the loop element 3 is 310 mm corresponding to about 3/2 wavelength with respect to the frequency of 880 MHz. The rectangular shape was 60 mm long and 90 mm wide.

  In addition, a 48 mm vertical line, which is a length corresponding to a length of ¼ wavelength with respect to a frequency of 880 MHz, is extended vertically from the first feeding point 10 to form the first element 4, A 25 mm horizontal line corresponding to a length of 1/8 wavelength with respect to a frequency of 940 MHz was extended in the left horizontal direction from the lower left corner of the lower side of the rectangular loop element 3 to form a second element 5.

  Further, an auxiliary vertical filament 6 having a length of 48 mm branched from a position 1/3 from the left corner of the lower side of the rectangular shape of the loop element 3 was provided.

  The loop antenna 2 is provided by printing directly on the indoor side of the window glass plate surface of an automobile, or by sticking what is printed on a sticker or sheet.

  Furthermore, the internal conducting wire 12 a of the coaxial cable 12 was connected to the first feeding point 10, and the external conducting wire 12 b was connected to the second feeding point 11.

  The antenna 2 in which the first element 4 and the second element 5 are arranged as described above was adjusted so that the reception gain in the mobile phone band of 800 to 960 MHz band was increased.

  The VSWR characteristics of the antenna of FIG. 3 arranged as described above were as low as 1.5 or less over the entire mobile phone band (800 to 960 MHz), and could cover the entire mobile phone band.

  Further, when the antenna of FIG. 3 arranged in this way is represented by a gain ratio when the gain of the dipole antenna is 0 dB (hereinafter abbreviated as a dipole antenna ratio), it is as shown in the frequency characteristic diagram of FIG. In addition, an average of -6.2 dB in the 800 to 960 MHz band was obtained, and a good result exceeding the transmission / reception gain of -10.0 dB, which is the average of conventional glass antennas used for practical use, was obtained.

It can be seen that an antenna that does not impair the field of view in spite of such a simple configuration can be provided, and the gain is high enough to be practically used.
[Example 4]
As shown in FIG. 4, in Example 4, the loop element 3 has a rectangular shape with a length of 80 mm and a width of 115 mm, and the first feeding point 10 and the second feeding point 11 are the lower sides of the rectangular shape of the loop element 3. Are arranged in the right horizontal direction from the right corner of each via a lead wire 7 having a length of 40 mm, and the distance between both lead wires 7 is 5 mm in the vertical direction.

  Further, a horizontal line having a length of 45 mm in the left horizontal direction from the first feeding point 10 is provided close to the inner side of the lower side of the loop element 3, and a vertical line having a length of 60 mm is bent upward from the left end of the horizontal line. A first element 4 refracted into an L shape by providing a filament was obtained.

  Furthermore, a horizontal line having a length of 55 mm corresponding to the length of 1/8 wavelength of the transmitted / received radio wave is extended in the horizontal direction on the left side from the left corner of the lower side of the rectangular loop element 3 to form a second element 5.

  The loop antenna 2 is provided by printing directly on the indoor side of the window glass plate surface of an automobile, or by sticking what is printed on a sticker or sheet.

  Furthermore, the internal conducting wire 12 a of the coaxial cable 12 was connected to the first feeding point 10, and the external conducting wire 12 b was connected to the second feeding point 11.

  The antenna 2 in which the first element 4 and the second element 5 are arranged as described above was adjusted so that the reception gain in the UHF band of the TV broadcast wave in the 470 to 770 MHz band was increased.

  The VSWR characteristics in the entire TV broadcast wave UHF band (470 to 770 MHz) of the antenna shown in FIG. 4 thus obtained were also low as in the first embodiment, and the entire TV broadcast wave UHF band could be covered. .

  Further, when the gain of the dipole antenna is set to 0 dB for the antenna of FIG. 4 arranged in this way (hereinafter abbreviated as a dipole antenna ratio), the average of the 470 to 770 MHz band is −9. It was 1 dB, and a good result was obtained that exceeded the transmission / reception gain of −20.0 dB, which is the average of glass antennas that have been put to practical use in the past.

It can be seen that an antenna that does not impair the field of view in spite of such a simple configuration can be provided, and the gain is high enough to be practically used.
[Example 5]
In the fifth embodiment shown in FIG. 5, the loop element 3 has a rectangular shape with a length of 80 mm and a width of 110 mm. The first feeding point 10 and the second feeding point 11 The distance between both feeding points is 2 mm.

  Further, a horizontal line having a length of 105 mm in the left horizontal direction from the first feeding point 10 is provided close to the inner side of the lower side of the loop element 3 at a distance of 5 mm, and is bent upward from the left end of the horizontal line, A first linear element 4 refracted into an L-shape was provided by providing a vertical linear line having a length of 70 mm close to the inside of the vertical side of the loop element 3 at a distance a of 5 mm.

  Furthermore, a horizontal filament having a length of 45 mm corresponding to the length of 1/8 wavelength of the transmitted / received radio wave is extended in the horizontal direction from the right corner of the upper side of the rectangular loop element 3 to form the second element 5, and the loop A second element 5 ′ having a length of 70 mm corresponding to the length of a quarter wavelength of the transmitted / received radio wave is provided near the lower side of the lower side of the element 3 from the second feeding point 11.

  The loop antenna 2 is provided by printing directly on the indoor side of the window glass plate surface of an automobile, or by sticking what is printed on a sticker or sheet.

  Furthermore, the internal conducting wire 12 a of the coaxial cable 12 was connected to the first feeding point 10, and the external conducting wire 12 b was connected to the second feeding point 11.

  The antenna 2 in which the first element 3 and the second element 4 are arranged as described above was adjusted so that the reception gain in the UHF band of TV broadcast waves in the 470 to 770 MHz band was increased.

  The VSWR characteristics of the antenna shown in FIG. 5 thus obtained over the entire TV broadcast wave UHF band (470 to 770 MHz) were also low, as in Example 1, and could cover the entire TV broadcast wave UHF band. .

  Further, when the gain of the dipole antenna is set to 0 dB for the antenna of FIG. 5 arranged as described above (hereinafter, abbreviated as a dipole antenna ratio), the average of 470 to 770 MHz band is −8. It was 8 dB, and a good result was obtained that exceeded the transmission / reception gain of −20.0 dB, which is the average of the conventional glass antennas used for practical use.

It can be seen that an antenna that does not impair the field of view in spite of such a simple configuration can be provided, and the gain is high enough to be practically used.
[Comparative Example 1]
In Comparative Example 1 shown in FIG. 6, the square loop element 3 ′ has a square shape with a length of 100 mm and a width of 100 mm, and the first feeding point 10 ′ and the second feeding point 11 ′ are the same as those of the loop element 3 ′. This is a cubic quad antenna pattern described in Non-Patent Document 1, which is arranged at a substantially central position on the lower side of a square shape and the interval between both feeding points is 2 mm.

  The loop antenna 2 'of the comparative example is provided by printing directly on the indoor side of the window glass plate surface of an automobile or by sticking a printed matter on a seal or sheet.

  Further, the inner conductor 12a of the coaxial cable 12 was connected to the first feeding point 10 ', and the outer conductor 12b was connected to the second feeding point 11.

  The antenna 2 in which the first element 3 and the second element 4 are arranged as described above was adjusted so that the reception gain in the UHF band of TV broadcast waves in the 470 to 770 MHz band was increased.

  The VSWR characteristics of the antenna of FIG. 6 arranged in this way are good in the TV broadcast wave UHF band (470 to 770 MHz), although the VSWR characteristics at a frequency around 650 MHz are good as shown in FIG. It can be seen that the entire TV broadcast wave UHF band cannot be covered.

The front view of the antenna pattern of Example 1 of this invention. The front view of the antenna pattern of Example 2 of this invention. The front view of the antenna pattern of Example 3 of this invention. The front view of the antenna pattern of Example 4 of this invention. The front view of the antenna pattern of Example 5 of this invention. The front view of the antenna pattern of the comparative example 1. FIG. The frequency characteristic figure of the UHF band (470-770 MHz) of the antenna of Example 1 of this invention. The frequency characteristic figure of the mobile telephone band (800-960 MHz) of the antenna of Example 3 of this invention. The VSWR characteristic figure of the antenna of Example 1 of this invention. The VSWR characteristic figure of the antenna of the comparative example 1. FIG. The figure which provided the antenna of this invention in the front window glass of the vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Window glass 2 Loop antenna of this invention 3 Loop element 4 1st element 5, 5 '2nd element 6 Auxiliary vertical wire 7 Lead wire 10 1st feed point 11 2nd feed point 12 Coaxial cable 12a Internal conductor 12b External conductor

Claims (4)

An antenna made of conductive wire disposed on a window glass surface of a moving body such as an automobile or a surface of an insulating member of a body, wherein the first feeding point and the second feeding point are provided close to each other, and the first feeding point A loop element having a length of 1 to 2 wavelengths of transmission / reception radio waves having a conductive wire disposed from to a second feeding point, and either one of the feeding points or a lead line from the feeding point A first element for impedance adjustment having a length of ¼ wavelength to ¾ wavelength of a transmission / reception radio wave branched and extended inside the loop element, and branched from the middle of the loop element to the outside of the loop element A vehicular antenna comprising a second element having a length of 1/16 to 1/4 wavelength extended. The first element and a line portion adjacent to a line of a loop element extending from a feeding point side that is substantially parallel to the first element and connected to the feeding point that is connected to the first element. 2. The vehicle antenna according to claim 1, wherein the interval is 0.1 mm to 1/4 wavelength, and the length is 1/8 wavelength to 3/4 wavelength. The second element having a length of 1/16 to ¼ wavelength extending from the one of the feeding points to the outer side of the loop element is further provided. The vehicle antenna according to 2. 4. The antenna pattern is directly formed on a surface made of a window glass or an insulating member of a moving body such as an automobile, or a transparent seal or sheet on which the pattern is printed is pasted. The vehicle antenna according to any one of the above.

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