JP2012044254A - Vehicle antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain highly sensitive and stable receiving performance in a non-grounded vehicle antenna for broadcast wave reception, provided on a vehicle window glass.SOLUTION: The antenna constituted by lines disposed on a vehicle window includes: an inside element extending in a direction apart from a metal flange, and being connected to either one of a first feed point and a second feed point each disposed in the vicinity of one another; and an outside loop element including a clockwise line and a counterclockwise line extending from each of the two feed points along the flange in opposite directions apart from each other so as to surround the inside element. The outside loop element forms a loop shape having an opening so as to surround the inside element, by high frequency conduction between each tip portion of the clockwise line and the counterclockwise line.

Description

  The present invention relates to an ungrounded antenna suitable for receiving terrestrial digital television broadcast waves and UHF band analog television broadcast waves provided in a window of a vehicle.

  In recent years, television broadcast waves in Japan are being shifted from terrestrial analog television broadcasts in the VHF band having a frequency of 90 to 220 MHz and UHF bands having a frequency of 470 to 770 MHz to digital terrestrial television broadcasts having a frequency of 470 to 710 MHz.

  Outside Japan, terrestrial digital television broadcasting with a frequency of 698 to 806 MHz or the like has been put into practical use, and correspondence to terrestrial digital broadcasting is also progressing as an antenna mounted on a car or a broadcasting radio wave transmission / reception device.

  In transmission / reception of such terrestrial digital television broadcast waves, it is necessary to make the reception sensitivity particularly high compared with transmission / reception of terrestrial analog broadcasts, and therefore ungrounded antennas are often adopted as antenna systems.

  For example, Japanese Patent Application Laid-Open No. 2005-229140 by the present applicant discloses a linear antenna disposed on a window glass surface of a moving body such as an automobile or an insulating member surface of a body, and is a transmission / reception extended from a first feeding point. A first element having a length of ¼ wavelength or ¾ wavelength of a radio wave, a second feeding point in the vicinity of the first feeding point, and the first element from the second feeding point There is disclosed a vehicular antenna comprising a second element in a closed loop shape having a length of one or more wavelengths of transmission / reception radio waves extended so as to surround (for example, refer to Patent Document 1).

  On the other hand, in Japanese Patent Application Laid-Open No. 2007-53505 by the present applicant, an antenna composed of conductive wires disposed on a window glass surface of a moving body such as an automobile or an insulating member surface of a body, the first feeding point and A loop element having a length of one to two wavelengths of a transmission / reception radio wave in which a second feeding point is provided adjacently and a conductive wire is disposed from the first feeding point to the second feeding point; and the feeding point A first element having a length of ¼ wavelength to ¾ wavelength of a transmission / reception radio wave extending from any one of the above, and 1/16 extending from the middle of the loop element to the outside of the loop element A vehicular antenna is disclosed that is a loop antenna including a second element having a length of ˜¼ wavelength (see, for example, Patent Document 2).

JP 2005-229140 A JP 2007-53505 A

  As described above, the antenna described in Patent Document 1 stabilizes the electric field at the tip of the hot-side element by surrounding the hot-side element that is susceptible to external influences with a closed-loop ground-side element, and Although it is difficult to be affected by the antenna performance due to, etc., and a method to obtain a suitable reception sensitivity is adopted, when tuning the impedance of the antenna pattern according to the line length, the ground side element is closed loop For this reason, there is a problem in that the length is difficult to adjust and the degree of freedom in tuning is small compared to an open loop filament.

  The antenna described in Patent Document 2 is also an antenna having a basic pattern of a loop antenna that connects the power supply terminals with the hot-side power supply point and the ground-side power supply point close to each other. As with the problem of, when tuning is performed by adjusting the impedance of the antenna pattern, the adjustment of the loop element wire length is difficult to adjust compared to the open loop wire strip. There is a problem that the degree of freedom becomes small.

  The present invention has been made in view of such a problem, and is less susceptible to the antenna performance due to the antenna installation location and the human body, and has the conventional performance of reducing the substantial antenna area. An object of the present invention is to provide an antenna suitable for receiving a terrestrial digital television broadcast wave that facilitates tuning of the antenna pattern while improving the antenna performance more than before.

  That is, the present invention is an antenna constituted by a line disposed on a window of a vehicle, wherein the first feeding point and the second feeding point are arranged close to each other, and the two feeding points are arranged. And an inner element extending in a direction away from the metal flange constituting the opening of the window and surrounding the inner element in opposite directions away from each other along the flange from each of the two feeding points. An outer loop element including a clockwise line and a counterclockwise line extending to each other, and the outer loop element has a tip portion of each of the clockwise line and the counterclockwise line. It is a vehicle antenna characterized by having a loop shape having an opening so as to surround the inner element by conducting at high frequency.

  Alternatively, in the present invention, the clockwise line and the counterclockwise line are disposed at positions close to each other so as to be capacitively coupled to each other. The vehicle described above, wherein the anti-clockwise line is configured to conduct at high frequency, and the capacitive coupling portion is provided on a side opposite to the side on which the two feeding points are provided. It is an antenna.

  Alternatively, in the present invention, the length of the portion where the tip of the clockwise line and the tip of the counterclockwise line are close to each other is from 10 mm to one wavelength of transmitted / received radio waves. This is the vehicle antenna described above.

  Alternatively, in the present invention, a first auxiliary line is provided between the clockwise line and the counterclockwise line, and one end of the first auxiliary line has the clockwise line. It is disposed at a position close to the tip of the strip so as to be capacitively coupled, and the other end is disposed at a position close to be capacitively coupled to the tip of the counterclockwise linear strip, whereby the clockwise line In the above-described vehicle antenna, the strip and the counterclockwise linear strip are electrically connected in a high frequency manner, and the outer loop element forms a loop shape having an opening.

  Alternatively, in the present invention, the length of the portion where the tip of the clockwise wire and the one end of the first auxiliary wire are close to each other, and the tip of the counterclockwise wire and the first The length of the part where the other end of the auxiliary wire is close is 10 mm to one wavelength of the transmitted / received radio wave.

  Alternatively, the present invention is the above-described vehicle antenna, wherein the length of the inner element is approximately ¼ wavelength of transmitted / received radio waves.

  Alternatively, the present invention is the above-described vehicular antenna, characterized in that a second auxiliary wire that bends and extends from the tip of the inner element is provided.

  Alternatively, according to the present invention, the second inner element is disposed close to and in parallel with the first inner element so as to be capacitively coupled to the first inner element and the first inner element. And the second inner element is extended from a feeding point different from the feeding point to which the first inner element is connected.

  Alternatively, the present invention is the above-described vehicle antenna, wherein the outer loop element has an electrical length of 1 to 2 wavelengths of transmitted / received radio waves.

  Alternatively, in the present invention, the one side connected to the feeding point of the clockwise wire is constituted by a plurality of parallel wires, and both ends of the wires are connected to each other. This is a vehicle antenna.

  Alternatively, the present invention is characterized in that one side connected to the feeding point of the counterclockwise line is constituted by a plurality of parallel lines, and both ends of the plurality of lines are connected. This is the vehicle antenna described above.

  Alternatively, the present invention is a vehicle antenna characterized in that the vehicle antenna according to any one of the above is directly printed on a window glass surface of a vehicle or a sheet on which the pattern is printed is attached.

  According to the present invention, it is difficult to affect the antenna performance due to the antenna installation location or the human body in the automobile, and the antenna pattern can be easily tuned and the antenna performance can be improved while reducing the substantial antenna area. Thus, the terrestrial digital television broadcast wave can be suitably received.

  In addition, the antenna of the present invention has an antenna impedance that hardly changes depending on the presence or absence of a person riding in the vehicle and has a simple configuration, so that it can provide an antenna that does not impair the field of view, and the reception gain can be increased. .

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 frequency characteristic figure of the antenna of Example 1 of this invention and Comparative Examples 1 and 2. FIG. The front view of the antenna pattern of the comparative example 1. FIG. The front view of the antenna pattern of the comparative example 2. FIG.

  The automobile antenna 2 according to the embodiment of the present invention has a first feeding point 6 and a second feeding point 7 disposed close to each other on a window glass surface in the vicinity of the opening of the metal flange 3 of the automobile. An inner element 10 connected to one of the two feeding points and extending inward of the opening away from the metal flange 3, and extending in the opposite direction away from each other along the flange from each of the two feeding points. An outer loop element 20 having at least two lines of a clockwise line 21 and a counterclockwise line 22 is included so as to surround the element.

  The inner element 10 is an element including a line 11 extending from the second feeding point 7 and extending in a direction away from the nearest opening side of the metal flange 3, and the outer loop element 20 having an outer loop shape is roughly divided into two. It is an element extended in the direction to divide. In FIG. 1, the example in which the inner element 10 extends from the second feeding point 7 is illustrated, but the inner element 10 may extend from the first feeding point 6.

  On the other hand, the outer loop element 20 extends in the opposite direction from each of the two feeding points 6 and 7 along the opening side of the metal flange so as to be separated from each other, and is arranged to surround the inner element 10. 21 and counterclockwise filament 22 are provided, and the two filaments are folded back so that the tips of the filaments face each other, and the shape of each filament is U-shaped or reversed. It was made into the shape of a U-shape (or a substantially U-shape or a substantially inverted U-shape in which some corners are substantially arc-shaped).

  An overlap portion 24 is provided so that the tip portions of the clockwise wire 21 and the counterclockwise wire 22 folded so that the tip portions face each other are close to each other, and the two wires are The outer loop element 20 was formed by the clockwise line 21 and the counterclockwise line 22 by capacitive coupling.

  Further, as the inner element 10, the first inner filament 11 is extended from either one of the two feeding points 6 and 7 toward the inner center of the loop element, but as shown in FIG. The second inner filament 12 may be extended in the same direction as the first inner filament 11 from another feeding point.

  When two inner filaments are provided, capacitive coupling may be performed by bringing the first inner filament 11 and the second inner filament 12 close to each other. The length of the first inner filament 11 and the length of the second inner filament 12 may be different as shown in FIG. 2 or the same length. By making the two inner filaments have different lengths, the antenna characteristics can be broadened. Also, by making the two inner filaments the same length, the sensitivity can be improved in the vicinity of the resonance frequency.

  The outer loop element 20 composed of two lines, the clockwise line 21 and the counterclockwise line 22, is configured such that the tip of the clockwise line 21 and the tip of the counterclockwise line 22 are capacitively coupled. Although it is a loop shape having openings that are close to each other and overlapped, it is in a non-conductive state that is open in terms of direct current, but is in a conductive state when receiving high-frequency radio waves, and the first state shown in FIG. An effect equivalent to or more than that of the conventional antenna pattern in a DC state from the feeding point 6 to the second feeding point 7 can be obtained.

  As shown in FIG. 1 to FIG. 4, the line portions that are adjacent and capacitively coupled by the overlap portion 24 in which the tip portions of the clockwise line 21 and the counterclockwise line 22 of the outer loop element 20 are overlapped are shown. It is preferable that the second feeding point 7 is provided on the side opposite to the side where the second feeding point 7 is located.

  Further, as shown in FIG. 5, the clockwise line 21 and the counterclockwise counterclockwise line 22 of the outer loop element 20 are stretched so that the leading ends of the elements do not overlap, Auxiliary wire 23 is provided between the portions, one end side of auxiliary wire 23 and the tip of clockwise wire 21 are overlapped so as to be capacitively coupled, and the other end of auxiliary wire 23 You may make it provide the overlap parts 24 and 25 in several places so that it may adjoin and may overlap so that the front-end | tip part of the counterclockwise line 22 may carry out capacitive coupling.

  The length of the line from either the first feeding point 6 or the second feeding point 7 to the tip of the inner element 10 is set to a quarter wavelength of the substantially intermediate frequency of the transmission / reception frequency band. Is preferred.

  Further, as shown in FIG. 4, the auxiliary filament 13 that is orthogonal to the inner filament 11 of the inner element 10 can be extended from the tip of the inner filament 11. The resonance frequency and impedance can be adjusted by changing the length and extending direction of the auxiliary filament. For example, FIG. 4 shows an example in which the auxiliary filament 13 is bent at 90 ° from the inner filament 11, but this angle may be any number.

  In FIG. 4, the auxiliary filament 13 that is orthogonal to the inner filament 11 of the inner element 10 is extended, and a part of the outer loop element 20 is formed in an arc shape. However, it is necessary to apply both of these. However, only one of them may be applied.

  Further, in the overlap portion 24, the length (electricity) in which the overlap portion is regarded as one line among the respective lines of the outer loop element 20 constituted by the clockwise line 21 and the counterclockwise line 22. The total length is preferably 1 to 2 wavelengths of transmitted / received radio waves.

  Furthermore, the length of the line of the overlap portion 24 in which the tip of the clockwise line 21 and the tip of the counterclockwise line 22 are arranged close to each other is adjusted so that the VSWR of the antenna is lowered. Is preferred. Specifically, the length of the portion where the tip of the clockwise wire 21 and the tip of the counterclockwise wire 22 are close to each other and capacitively coupled (A in FIG. 1) is a length of 10 mm to 1 wavelength. Good.

  As described above, in the overlap portion 24 at each end of the clockwise line 21 and the counterclockwise line 22, the overlapping line length is set to 10 mm or more. This is because the effect that the clockwise line 21 and the counterclockwise line 22 can be electrically regarded as one line is reduced. Moreover, the reason why the length of the overlapping filaments is set to one wavelength or less is that when the length of the overlapping filaments is one wavelength or more, preferable capacitive coupling can be obtained, but the filaments become complicated. is there.

  Further, as shown in FIG. 3, one side connected to the second feeding point 7 of the clockwise line 21 is constituted by a plurality of lines, and the plurality of lines are arranged in parallel, You may make it connect the front-end | tip parts.

  Further, one side connected to the second feeding point 7 of the counterclockwise line 22 of the outer loop element 20 is constituted by a plurality of lines, and the plurality of lines are arranged in parallel, You may make it connect front-end | tip parts.

  The number of horizontal lines provided on the clockwise line 21 and the counterclockwise line 22 may be two or four or more instead of the three illustrated. Further, in both the clockwise line 21 and the counterclockwise line 22, a plurality of lines may be arranged in parallel. On the other hand, a plurality of lines are arranged in parallel. Also good. Further, the number of parallel lines provided on the clockwise line 21 and the counterclockwise line 22 may be different.

  Further, in FIG. 3, two inner filaments are provided, and a plurality of parallel filaments are arranged on the clockwise filament 21 and the counterclockwise filament 22, but it is necessary to apply both of these. However, only one of them may be applied.

  Further, the antenna pattern may be directly printed on the surface of the vehicle window glass 1 or a sheet on which the antenna pattern is printed may be attached.

  The outer shape of the outer loop element 20 is generally rectangular as shown in FIG. 1 to FIG. 3 and FIG. 5, but as shown in FIG. When the shape of the part is an arc shape, a part of the outer loop element 20 may have an arc shape according to the arc shape. Although not shown, the outer loop element 20 may have a circular shape, a square shape, a rhombus shape, or a polygonal shape.

  An internal conductor and an external conductor of a coaxial cable (not shown) were connected to each of the first feeding point 6 and the second feeding point 7.

  As the window glass 1 for an automobile or the like, the antenna of the present embodiment may be provided on any of the front window glass, the rear window glass, the side window glass, the sunroof, and the like. Not only a plate but also a transparent resin plate or a light transmission member made of a composite of a glass plate and a transparent resin plate is included.

  In addition, the antenna of the present embodiment has an antenna pattern on the window glass surface of the upper margin part, the lower margin part, the front window glass, the side window glass, and the roof window glass of the heating filament of the rear window glass. May be directly printed with a conductive paste, or may be printed on a transparent seal or transparent sheet having a small thickness and adhered to the inner surface of the window glass surface or a portion made of an insulating material.

  Further, the antenna 2 may be provided at only one location on the window glass of the automobile. However, the antenna may be provided at a plurality of locations on the same window glass or at each of the plurality of window glasses. May be used to receive diversity. In this case, the plurality of antennas constituting the diversity antenna may be the same pattern or different patterns, and the reception sensitivity can be further improved by performing diversity reception.

  The operation of the present invention will be described below.

  In the antenna of the present embodiment, as the outer loop element 20, a clockwise line 21 extending so as to surround the inner element 10 clockwise from the second feeding point 7, and counterclockwise from the first feeding point 6. The ends of the two counterclockwise wires 22 extending so as to surround the inner element 10 are closely overlapped so as to be capacitively coupled to each other, and there is an opening having a shape surrounding the inner element 10. The loop was made. For this reason, since the front end of the clockwise line 21 and the front end of the counterclockwise line 22 are opened, adjusting the length of the overlapping line part 24 of each line can improve the frequency characteristics. The impedance on the outer loop element 20 side, that is, the impedance of the antenna can be easily adjusted while minimizing the influence.

  The outer loop element 20 is open and non-conducting in terms of direct current, but is in a conducting state in terms of high frequency, so that the conventional antenna in which the outer loop element as shown in FIG. The same reception characteristics can be obtained.

  Since the inner element 10 is surrounded by the outer loop element 20 having an open loop shape, the electric field at the tip of the antenna that is susceptible to external influences can be stabilized, and the influence of adjacent conductors such as the human body can be reduced. Can be small.

  Various embodiments of the present invention will be described below.

[Example 1]
FIG. 1 shows an antenna pattern according to the first embodiment of the present invention, and shows a non-grounded glass antenna provided in the vicinity of an upper corner portion of a rear window glass of an automobile.

  In the antenna according to the first embodiment, the first feeding point 6 and the second feeding point 7 are disposed in the vicinity of the upper side near the upper left corner of the opening of the metal flange 3, and An inner element 10 connected and extending substantially vertically downwardly away from the upper side of the metal flange 3, and extending in opposite directions away from each other along the flange from the first feeding point 6 and the second feeding point 7, It comprises an outer loop element 20 having two lines, a clockwise line 21 and a counterclockwise line 22 arranged so as to surround the inner element.

  That is, the clockwise line 21 is a U-shaped element extending clockwise around the inner element 10 from the second feeding point 7 so as to surround the inner element 10, and the counterclockwise line 22 is This is an inverted U-shaped element extending from the first feeding point 6 so as to surround the inner element 10 counterclockwise around the inner element 10.

  Further, the two ends of the clockwise line 21 and the counterclockwise line 22 are capacitively coupled so that the end portions of the respective lines are overlapped close to each other so as to surround the inner element 10. A loop element is provided to form a substantially rectangular loop shape in which the tip of each element constituting the outer loop element is opened.

  Each filament length of the antenna of Example 1 is as follows.

  The length of the line from the first feeding point 6 to the tip of the inner element 10 is ¼ wavelength of the radio wave at the substantially intermediate frequency 600 MHz of the transmission / reception frequency, and the wavelength reduction rate (about 0.6) of the glass plate 1 To 75 mm.

  The length of the horizontal line extending from the second feeding point 7 of the clockwise line 21 is 47.5 mm, the vertical line extending downward from its tip is 135 mm, and it is folded back in a U-shape from the lower end of the vertical line. The length of the folded line is 70 mm.

  Further, the length of the horizontal line extending in the corner direction from the first feeding point 6 of the counterclockwise line 22 is 47.5 mm, the vertical line extending downward from the tip thereof is 130 mm, and the lower end of the vertical line The length of the folded line that is folded back in a U-shape is 110 mm.

  Furthermore, the length A of the overlap portion 24 where the folded line of the clockwise line 21 and the folded line of the counterclockwise line 22 are close is 50 mm, and the interval between the lines is 5 mm.

  The distance between each horizontal line of the clockwise line 21 and the counterclockwise line 22 and the upper side of the flange opening is 10 mm, and the distance between the vertical line of the counterclockwise line 22 and the vertical side of the flange opening is 10 mm. The interval was 10 mm.

  The 1st feeding point 6 and the 2nd feeding point 7 were made into the rectangular shape of 10 mm in length and 15 mm in width, respectively, and the space | interval between each feeding point was 5 mm.

  The antenna according to the present embodiment is printed with a conductive ceramic paste at a predetermined position on the indoor surface side of the window glass plate with a width of 0.7 mm, dried, baked in a heating furnace, and not shown. The center conductor of a coaxial cable (not shown) connected to the tuner was connected to the second feeding point 7 and the outer conductor was connected to the first feeding point 6.

  When the terrestrial digital TV broadcast wave receiving antenna of Example 1 created in this way was provided on the rear window glass of the automobile and received radio waves in the terrestrial digital TV broadcast wave band with a frequency of 470 to 710 MHz, the thick signal in FIG. As shown by the solid line, a good frequency characteristic with an average gain of −7.0 dB is obtained, and the average gain of the antenna of Comparative Example 1 (see FIG. 7) described later shown by the thin solid line in FIG. And compared with the antenna (refer FIG. 8) average gain -8.1dB of the comparative example 2 mentioned later shown with the dotted line of FIG. 6, the frequency characteristic more than equivalent was acquired.

  In addition, the antenna shown in FIG. 1 obtained in this way provides an antenna that has little change in antenna impedance even when a person is in the vehicle and does not impair the field of view because of its simple configuration. In addition, the gain is high, and the antenna tuning is easier than the conventional one.

[Example 2]
The second embodiment is a modified pattern of the first embodiment as shown in FIG. The second inner filament 12 is extended from the first feeding point 6 in the same direction and substantially parallel to the first inner filament 11 of the inner element 10 extending from the second feeding point 7, and further, The difference from the first embodiment is that the inner filament 11 and the second inner filament 12 are brought close to each other and capacitively coupled. Since the configuration other than the above is exactly the same as that of the first embodiment, the same reference numerals are given and the description thereof is omitted.

  The antenna according to the present embodiment is printed with a conductive ceramic paste at a predetermined position on the indoor surface side of the window glass plate with a width of 0.7 mm, dried, baked in a heating furnace, and not shown. The center conductor of a coaxial cable (not shown) extending from the tuner was connected to the first feeding point 6 on the hot side, and the outer conductor was connected to the second feeding point 7 on the ground side.

  When the terrestrial digital television broadcast wave receiving antenna of Example 2 created in this way was provided on the rear window glass of the automobile and received as an antenna of a terrestrial digital TV broadcast wave band with a frequency of 470 to 710 MHz, Similarly, it was found that good transmission / reception performance was obtained and that it could be sufficiently put into practical use.

  In addition, the antenna of the second embodiment shown in FIG. 2 obtained in this way hardly changes the antenna impedance even when a person is on the vehicle and has a simple configuration, which may impair visibility. Antenna can be provided, the gain is high, the antenna tuning is easier than the conventional one, and it can be sufficiently put into practical use.

[Example 3]
Example 3 is a modified pattern of Example 2 as shown in FIG. In the antenna of the third embodiment, unlike the second embodiment described above, the U-shaped clockwise line 21 and the reverse U-shaped counterclockwise line 22 of the outer loop element 20 are connected to the second feeding point 7. Three horizontal filaments of the clockwise filament 21 to be connected were used, and the tips of the three horizontal filaments were connected by a vertical filament.

  Further, the number of the counterclockwise line 22 connected to the first feeding point 6 is three, and the tips of the three horizontal lines are connected by the vertical line. Other than this, the configuration is exactly the same as that of the second embodiment, and therefore, the same reference numerals are given and description thereof is omitted.

  When the terrestrial digital television broadcast wave receiving antenna according to the third embodiment having the above-described configuration is provided on the rear window glass of the automobile and the radio wave of the terrestrial digital television broadcast wave having a frequency of 470 to 710 MHz is received, it is as good as the second embodiment. Transmission / reception performance can be obtained and can be sufficiently put into practical use.

  Further, the antenna of the third embodiment shown in FIG. 3 obtained in this way has almost no change in antenna impedance even when a person is in the vehicle and has a simple configuration, which may impair visibility. Antenna can be provided, the gain is high, the antenna tuning is easier than the conventional one, and it can be sufficiently put into practical use.

  In addition, although the antenna of Example 3 added the multiple horizontal filament to the antenna of Example 2, the modification which added the multiple horizontal filament to the antenna of Example 1 is also contained in the category of this invention.

[Example 4]
The antenna of the fourth embodiment shown in FIG. 4 is different from the first embodiment in that the shape of the upper left corner portion of the outer loop element is a substantially quadrant arc shape, and is the same as the first embodiment in other points. . For this reason, the same code | symbol is attached | subjected to the same structure and those description is abbreviate | omitted.

  The antenna of Example 4 is provided in a round shape along the round shape of the upper corner of the opening of the window glass flange, and the first feeding point 6 and the second feeding point 7 are arranged on the upper left circle. This is an example of juxtaposition in the vicinity of an arc corner.

  The antenna of the fourth embodiment differs from the first embodiment described above in that the outer loop element 20 has a U-shape extending from the second feeding point 7 so as to surround the inner element 10 clockwise around the inner element 10. Two elements, a clockwise line 21 and a substantially inverted U-shaped counterclockwise line 22 having an arc portion extending so as to surround the inner element 10 counterclockwise from the first feeding point 6. The end portions of the two elements face each other, and the filaments at the end portions of the two elements are closely overlapped so as to be capacitively coupled to each other, and are arranged so as to surround the inner element 10. As a result, the outer loop element 20 has a substantially rectangular loop shape in which the ends of the respective filaments constituting the element are open and the upper left corner is a quarter arc shape.

  When the terrestrial digital television broadcast wave receiving antenna of Example 4 described above was provided on the rear window glass of the automobile and received radio waves in the terrestrial digital TV broadcast wave band having a frequency of 470 to 710 MHz, it was as good as in Example 1. Transmit / receive performance was obtained.

  In addition, the antenna shown in FIG. 4 obtained in this way provides an antenna that has almost no change in antenna impedance even when a person is on the vehicle and does not impair the field of view because of its simple configuration. The gain is high and the antenna tuning is easier than the conventional one.

  The antenna of the fourth embodiment has an auxiliary wire 13 added to the antenna of the first embodiment, and further, a part of the outer loop element 20 is formed in an arc shape. It is included in the category of the present invention.

[Example 5]
The fifth embodiment of the present invention shown in FIG. 5 is a modified pattern of the first embodiment. The substantially rectangular element of the outer loop element 20 is replaced with an L-shaped clockwise wire 21 and an inverted U-shaped anti-node. A part of each of the clockwise line 22 and the inverted L-shaped auxiliary line 23 is overlapped in close proximity so as to be capacitively coupled to each other, and arranged so as to surround the inner element 10, The loop element 20 was formed into a substantially rectangular loop shape in which the ends of the filaments constituting the loop element 20 were open. The inner element 10 is the same as that in the first embodiment. For this reason, the same code | symbol is attached | subjected to the same structure and those description is abbreviate | omitted.

  The clockwise line 21 is an L-shaped element which is connected to the second feeding point 7 and is composed of a horizontal line extending to the right side and a vertical line extending downward from the tip. Further, the counterclockwise line 22 is connected to the first feeding point 6 in the same manner as in the first embodiment, and is composed of a horizontal line extending to the left side, a vertical line extending downward from its tip, and a folded line that is folded back. This is an inverted U-shaped element.

  Further, an L-shaped auxiliary line 23 is provided between the clockwise line 21 and the counterclockwise line 22, and between the one end of the auxiliary line 23 and the clockwise line 21, and the L-shaped line Between the other end of the auxiliary wire 23 and the counterclockwise wire 22, an adjacent overlap portion was provided so as to be capacitively coupled to each other.

  When the terrestrial digital television broadcast wave receiving antenna according to the fifth embodiment having the above-described configuration is provided on the rear window glass of the automobile and a radio wave in the terrestrial digital television broadcast wave band having a frequency of 470 to 710 MHz is received, the same as in the first embodiment. Good transmission / reception performance was obtained.

  In addition, the antenna shown in FIG. 5 obtained in this way provides an antenna that hardly changes the antenna impedance even when a person is on the vehicle and does not impair the field of view because of its simple configuration. The gain is high and the antenna tuning is easier than the conventional one.

[Comparative Example 1]
The comparative example 1 shown in FIG. 7 is a pattern described in Patent Document 2, an inner element 10 ′ extending in the vertical direction from the second feeding point 7 ′ among the two neighboring feeding points, and the inner side This is an antenna provided with a substantially rectangular closed loop outer loop element 20 ′ connecting two feeding points 6 ′ and 7 ′ so as to surround the element 10 ′.

  The length of the filament 11 ′ of the inner element 10 ′ of the antenna 2 ′ of Comparative Example 1 is set to a quarter wavelength of a radio wave at a substantially intermediate frequency of 600 MHz of the transmission / reception frequency. 6) is multiplied to 75 mm, and the outer loop element 20 ′ has a substantially rectangular shape with the length of the vertical side of 140 mm and the length of the horizontal side of 130 mm.

  The distance between the upper side of the outer loop element 20 ′ and the upper side of the opening of the flange 3 ′ is 10 mm, and the distance between the vertical line of the outer loop element 20 ′ and the vertical side of the opening of the flange 3 ′ is 10 mm.

  The first feeding point 6 ′ and the second feeding point 7 ′ have rectangular shapes with a vertical side of 10 mm and a horizontal side of 15 mm, respectively, and the interval between the feeding points 6 ′ and 7 ′ is 5 mm.

  When the terrestrial digital TV broadcast wave receiving antenna 2 'of the comparative example 1 having the above-described configuration is provided on the rear window glass 1' of the automobile, radio waves in the terrestrial digital TV broadcast wave band having a frequency of 470 to 710 MHz are received. Frequency characteristic indicated by a thin solid line, and the average reception gain was -8.1 dB.

  According to the frequency characteristic diagram of FIG. 6, the antenna of Comparative Example 1 is slightly higher than the gain of the antenna of Example 1 in the band of 470 to 525 MHz and the band of 580 to 615 MHz, but the band of 525 to 580 MHz, And in the band of 615 to 710 MHz, the gain is considerably reduced as compared with the antenna of the first embodiment. Further, since the closed loop antenna pattern of Comparative Example 1 has a closed loop shape, it is not easy to adjust the antenna characteristics because it is not possible to adjust only the length of one side during tuning.

[Comparative Example 2]
The antenna pattern of Comparative Example 2 shown in FIG. 8 includes a clockwise line 21 ″ extending so as to surround the inner element 10 ″ clockwise from the second feeding point 7 ″ and the first feeding point 6 ″. It is arranged in a substantially rectangular shape in which two lines of an inverted U-shaped counterclockwise line 22 ″ extending so as to surround the inner element 10 ″ in the counterclockwise direction are arranged, but the counterclockwise line 22 ″ is arranged. Is bent downward before the tip of the clockwise wire 21 ", so that the tips of the clockwise wire 21" and the counterclockwise wire 22 "do not overlap each other, that is, the watch This is a pattern having an open substantially rectangular loop shape in which the winding line 21 "and the counterclockwise line 22" are not capacitively coupled.

  In the antenna 2 ″ of the comparative example 2, the inner element 10 ″ is constituted by one line 11 ″ that extends substantially vertically downward from the second feeding point 7 ″.

  The end of the counterclockwise line 22 "is bent downward so that the total length of the counterclockwise line 22" matches the total length of the counterclockwise line 22 of Example 1 (see FIG. 1). This is to make it happen.

  The lengths of the vertical and horizontal lines of the substantially rectangular portion of the outer loop element 20 ″ of the antenna 2 ″ of Comparative Example 2 are the same as the lengths of the vertical sides of the outer loop element of Comparative Example 1 and Example 1. The length of the side is 140 mm, the length of the lateral side is 130 mm, and the length of the counterclockwise line 22 ″ bent downward before the tip of the clockwise line 21 ″ is 35 mm. The lengths and intervals of the filaments other than the above are the same as those in Example 1 and Comparative Example 1.

  When the terrestrial digital television broadcast wave receiving antenna of Comparative Example 2 having the above-described configuration is provided on the rear window glass of the automobile and a radio wave in the terrestrial digital television broadcast wave band having a frequency of 470 to 710 MHz is received, the dotted line in FIG. Frequency characteristics were obtained, and the average reception gain was -8.1 dB.

  The frequency characteristic of the antenna of Comparative Example 2 is slightly higher than the gain of Example 1 in the band of 580 to 615 MHz as compared with the frequency characteristic of the antenna of Example 1 shown by the thick solid line in FIG. In the band of 580 MHz and the band of 580 to 710 MHz, the reception gain is considerably reduced as compared with the first embodiment.

  As described above, when the antenna of Comparative Example 2 and the antenna of Example 1 are compared, the antenna of Comparative Example 2 is constituted by the clockwise line 21 ″ and the counterclockwise line 22 ″ of the outer loop element 20 ″. Compared with the first embodiment in which the overlap portion is not provided in the loop-shaped opening and the two gains are overlapped in the opening, the receiving gain is not lowered. I understand that.

  As mentioned above, although demonstrated by the preferable Example, this invention is not limited to these, A various application is possible.

DESCRIPTION OF SYMBOLS 1 Window glass 2 Antenna 2 'of this invention, 2 "Comparative antenna 3, 3', 3" Metal flange 6, 6 ', 6 "1st feeding point 7, 7', 7" 2nd feeding point 10, 10 ', 10 "inner element 20, 20', 20" outer loop element 21 clockwise line 22 counterclockwise line 23 auxiliary line 24, 25 overlap part

Claims (12)

An antenna constituted by a wire disposed in a window of a vehicle,
The first feeding point and the second feeding point are arranged close to each other,
An inner element connected to either one of the two feeding points and extending in a direction away from the metal flange forming the opening of the window;
An outer loop element including a clockwise line and a counterclockwise line extending to surround the inner element in opposite directions away from each other along the flange from each of the two feeding points;
The outer loop element is configured to have a loop shape having an opening so as to surround the inner element by conducting high-frequency conduction between the distal ends of the clockwise line and the counterclockwise line. An antenna for a vehicle. By disposing the tip of the clockwise wire and the tip of the counterclockwise wire close to each other so as to be capacitively coupled to each other, the clockwise wire and the counterclockwise wire Configure to conduct at high frequency,
The vehicle antenna according to claim 1, wherein the capacitive coupling portion is provided on a side opposite to a side on which the two feeding points are provided.   3. The vehicle according to claim 2, wherein the length of the portion where the tip of the clockwise wire and the tip of the counterclockwise wire are close to each other is 10 mm to one wavelength of transmitted / received radio waves. Antenna. A first auxiliary wire is provided between the clockwise wire and the counterclockwise wire,
The first auxiliary wire is disposed at a position where one end thereof is capacitively coupled with the tip of the clockwise wire, and the other end is capacitively coupled with the tip of the counterclockwise wire. Placed in close proximity to
2. The vehicle according to claim 1, wherein the clockwise line and the counterclockwise line are electrically connected at a high frequency, and the outer loop element forms a loop shape having an opening. antenna.   The length of the portion where the tip of the clockwise wire and the one end of the first auxiliary wire are close to each other, and the tip of the counterclockwise wire and the other end of the first auxiliary wire 5. The vehicle antenna according to claim 4, wherein the length of the portion adjacent to the portion is 10 mm to one wavelength of transmitted / received radio waves.   The vehicle antenna according to any one of claims 1 to 5, wherein the length of the inner element is approximately a quarter wavelength of a transmitted / received radio wave.   The vehicular antenna according to any one of claims 1 to 6, further comprising a second auxiliary filament that bends and extends from a tip of the inner element. The inner element includes the first inner element and a second inner element disposed close to and parallel to the first inner element so as to be capacitively coupled to the first inner element. ,
The vehicular antenna according to any one of claims 1 to 7, wherein the second inner element extends from a feeding point different from a feeding point to which the first inner element is connected.   The vehicular antenna according to any one of claims 1 to 8, wherein an electrical length of the outer loop element is 1 to 2 wavelengths of transmission / reception radio waves.   The one side connected to the feeding point of the clockwise line is constituted by a plurality of parallel lines, and both ends of the plurality of lines are connected to each other. Vehicle antenna as described in one.   11. The structure according to claim 1, wherein one side connected to the feeding point of the counterclockwise line is constituted by a plurality of parallel lines, and both ends of the plurality of lines are connected to each other. The antenna for vehicles as described in any one.   12. The vehicle antenna according to claim 1, wherein the vehicle antenna according to any one of claims 1 to 11 is directly printed on a window glass surface of a vehicle, or a sheet on which the pattern is printed is attached.