JP2012029032A - Vehicle antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna for terrestrial digital TV broadcasting wave reception, which is not grounded to vehicle window glass, and to obtain stable reception performance with high sensitivity.SOLUTION: An antenna 2 includes a hot-side element 10 and a ground-side element 20 and is arranged on a vehicle window glass 1. The hot-side element 10 is connected to a hot-side feeding point 6 and includes a streak 11 extending in a direction apart from a body flange 3. The ground-side element 20 includes: a ground-side first element 21 extended clockwise from a ground-side feeding point 7 arranged near the hot-side feeding point 6; and a ground-side second element 22 extended counterclockwise from the ground-side feeding point 7. Tips of the ground-side first element 21 and the ground-side second element 22 are conducted in terms of a high frequency. Thus, the ground-side element 20 is made in a loop shape having an opening portion to surround the hot-side element 10.

Description

  The present invention relates to an ungrounded vehicle antenna suitable for receiving digital terrestrial television broadcast waves and UHF band analog television broadcast waves provided on a window glass of an automobile or the like.

  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).

  Similarly, Japanese Patent Laid-Open No. 2005-159657 by the present applicant discloses a polygonal or arcuate closed loop extending from a first feeding point disposed on a window glass surface of a moving body such as an automobile or an insulating member surface of the body. A first element having a shape and a second element provided closer to the first element than a second feeding point provided in the vicinity of the first feeding point inside the first element; The strip length of the first element is longer than one wavelength of the transmission / reception radio wave and longer than the strip length of the second element, and the strip length of the second element is 3/4 wavelength or 5 of the transmission / reception radio wave. A vehicular antenna is disclosed in which an external conductor and an internal conductor of a coaxial cable are connected to each of the first feeding point and the second feeding point as / 4 wavelength (for example, Patent Document 2). reference ).

JP 2005-229140 A JP 2005-159657 A

  As described above, the antennas described in Patent Documents 1 and 2 stabilize the electric field at the tip of the hot side element by surrounding the hot side element, which is susceptible to external influences, with a closed loop earth side element. And a technique for obtaining a suitable reception sensitivity by reducing the influence of the human body or the like on the antenna performance. However, when tuning is performed by adjusting the impedance of the antenna pattern, the length of the ground side element is closed loop, making it difficult to adjust the length compared to the open loop filament, and the degree of freedom in tuning is small. There was a problem of becoming.

  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 while facilitating tuning of an antenna pattern while maintaining it, improving antenna performance more than before.

  The present invention is an antenna including a hot side element and a ground side element and disposed on a window glass of a vehicle. The hot side element is connected to a hot side feeding point and extends in a direction away from a body flange. The ground side element includes a wire, and the ground side first element extends clockwise from the ground side power supply point provided in the vicinity of the hot side power supply point, and extends counterclockwise from the ground side power supply point. An earth-side second element, and the respective ends of the earth-side first element and the earth-side second element are electrically connected at a high frequency so that the earth-side element surrounds the hot-side element. A vehicular antenna having a loop shape having an opening.

  Alternatively, according to the present invention, in a side opposite to the side on the ground side feeding point side, the positions of the tips of the ground side first element and the ground side second element are close to each other so as to be capacitively coupled to each other. The above-mentioned vehicular antenna is characterized in that the ground-side first element and the ground-side second element are electrically connected in a high-frequency manner.

  Alternatively, in the present invention, an auxiliary wire is provided between the ground side first element and the ground side second element, and one end of the auxiliary wire is connected to the tip of the ground side first element. It is arranged at a position close to be capacitively coupled, and the other end is arranged at a position close to be capacitively coupled to the tip of the ground side second element, whereby the ground side first element and the ground are The above-described vehicle antenna, wherein the second side element is electrically connected to the second side element at a high frequency, and the ground side element forms a loop wire.

  Alternatively, in the present invention, at the tip of the ground side first element and the tip of the ground side second element, the length of the portion adjacent to the other wire is 10 mm to one wavelength. The above-described vehicle antenna is characterized.

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

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

  Alternatively, the present invention is the above-described vehicle antenna, wherein the electrical length of the ground-side element is 1 to 2 wavelengths of transmission / reception radio waves.

  Alternatively, the present invention is characterized in that one side connected to the ground side feeding point of the ground side first element is constituted by a plurality of parallel strips, and the ends of the plurality of strips are connected to each other. It is the above-mentioned vehicle antenna.

  Alternatively, the present invention is characterized in that one side connected to the ground-side feeding point of the second element on the ground side is constituted by a plurality of parallel filaments, and tip portions of the plurality of filaments are connected to each other. It is the above-mentioned vehicle antenna.

  Alternatively, the present invention is the vehicle antenna according to any one of the above-described features, in which any one of the above-described vehicle antennas is directly printed on a vehicle window glass surface 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 can provide an antenna that does not impair the field of view because the antenna impedance hardly changes depending on whether or not a person is on the vehicle, and has a simple structure, and has a high gain. be able to.

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.

  A glass antenna according to an embodiment of the present invention is an antenna for transmitting and receiving digital terrestrial television broadcast waves in and outside Japan, which is disposed on a window glass 1 of an automobile, and includes a hot-side element 10 extending from a hot-side feeding point, This is a non-grounded glass antenna comprising an earth-side element 20 extending from the side feeding point.

  The hot-side element 10 is an element that is on the glass surface and includes a filament 11 that extends from the hot-side feeding point 6 and extends in a direction away from the nearest opening side of the metal body flange 3.

  On the other hand, the earth-side element 20 extends from the earth-side feeding point 7 provided in the vicinity of the hot-side feeding point 6 clockwise around the hot-side element 10 in a direction surrounding the hot-side element 10. And two ground strips of the ground-side second element 22 extending in the direction surrounding the hot-side element 10 counterclockwise from the ground-side feeding point 7, and the tips of both the strips 21 and 22 are mutually connected. They are overlapped in close proximity so as to be capacitively coupled, and are formed in a loop shape having an opening so as to surround the hot-side element 10.

  Since the earth-side element 20 has a loop shape having the opening, the opening is in a non-conductive state that is open for direct current, but is in a conductive state when receiving high-frequency radio waves. At a high frequency, an effect equivalent to that of the conventional antenna pattern having a DC closed loop shown in FIG. 7 can be obtained.

  The tip of the ground side first element 21 and the tip of the ground side second element 22 are overlapped so that the ground side first element 21 and the ground side second element 22 of the ground side element 20 are capacitively coupled. The overlap portion 24 is preferably provided at a location far from the ground-side feeding point 7, for example, at a side opposite to the side where the ground-side feeding point 7 is located as shown in FIGS. 1 to 4.

  Further, as shown in FIG. 5, the clockwise ground side first element 21 and the counterclockwise ground side second element 22 of the ground side element 20 are stretched so that the tip ends of the elements do not overlap. Auxiliary wire 23 is provided between the tips of each element, and one end of auxiliary wire 23 and the tip of ground side first element 21 are close and overlapped so as to be capacitively coupled. The overlap portions 24 and 25 may be provided at a plurality of locations so that the other end portion of the first and second end portions of the ground side second element 22 are close and overlapped so as to be capacitively coupled.

  It is preferable that the length of the line from the hot-side feeding point 6 to the tip of the hot-side element 10 is a quarter wavelength of the substantially center frequency of the transmission / reception frequency band.

  In addition, as shown in FIG. 2, the auxiliary filament 12 that is orthogonal to the hot-side filament 11 of the hot-side element 10 can be extended from the tip of the hot-side filament 11. By changing the length of the auxiliary filament 12 and the extending direction, the resonance frequency and the impedance can be adjusted. For example, FIG. 2 shows an example in which the auxiliary filament 12 is bent at 90 ° from the hot filament 11, but this angle may be any number of times.

  FIG. 2 shows an example in which the number of horizontal lines of the ground side first element 21 is three and the number of horizontal lines of the ground side second element 22 is four, but the number is not limited thereto. Further, one horizontal line of the ground side first element 21 and the ground side second element 22 may be one, and the other horizontal line may be a plurality.

  Furthermore, the length of each line of the earth-side element 20 composed of the earth-side first element 21 and the earth-side second element 22 is summed up, and the overlapping length is regarded as one line (electricity The length is preferably 1 to 2 wavelengths of transmitted / received radio waves.

  Furthermore, in the overlap portion 24, the length of the line where the tip of the ground side first element 21 of the ground side element 20 and the tip of the ground side second element 22 overlap is such that the VSWR of the antenna becomes low. It is preferable to adjust to. Specifically, the length of the portion where the tip of the ground side first element 21 and the tip of the ground side second element 22 are close to each other and capacitively coupled (A in FIG. 1) is 10 mm to one wavelength. There should be.

  As described above, the length of the overlapping line in the overlap portion 24 is set to 10 mm or more. If it is less than 10 mm, the capacitive coupling becomes weak, and the ground side first element 21 and the ground side second element 22 are reduced. This is because the effect that can be regarded as a single filament is reduced. In addition, the length of the overlapping filaments is set to one wavelength or less, but a preferable capacitive coupling is obtained when the wavelength is one wavelength or more, but the filaments become complicated.

  Further, as shown in FIG. 2, one side connected to the ground-side feeding point 7 of the ground-side first element 21 is constituted by a plurality of filaments, and the plurality of filaments are arranged in parallel, You may make it connect the front-end | tip parts.

  In addition, one side connected to the ground-side feeding point 7 of the ground-side second element 22 of the ground-side element 20 is constituted by a plurality of filaments, the plurality of filaments are arranged in parallel, and each tip You may make it connect parts.

  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.

  As the shape of the ground side element 20, the rectangular shape shown in FIGS. 1, 2, and 5 is generally used. However, as shown in FIG. 3, the arcuate shape of the corner portion of the metal flange 3 is used. According to the shape, the earth side element 20 may have a shape including an arcuate line, and may have an elliptical shape as shown in FIG. Further, although not shown, the earth side element 20 may be formed in a square, rhombus, or polygonal shape.

  The hot-side feeding point 6 and the ground-side feeding point 7 are connected to an internal conductor and an external conductor of a coaxial cable (not shown).

  Furthermore, the earth side element 20 branches from the tip of the earth side feeding point 7 through the lead wire 26 to the earth side first element 21 and the earth side second element 22 so as to extend the wires in opposite directions. Alternatively, the ground-side first element 21 and the ground-side second element 22 may be directly connected to the ground-side power feeding point 7 without going through the lead wire 26 from the ground-side power feeding point 7.

  As window glass 1 for automobiles, it may be provided on any of window glass such as front window glass, rear window glass, side window glass and sunroof, and the window glass is not only a glass plate but also a transparent resin. A case of a plate or a composite of a glass plate and a transparent resin plate is also included.

  In the antenna of this embodiment, the antenna pattern is formed 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. Printing may be performed directly using a conductive paste, or may be printed on a transparent seal or transparent sheet having a small thickness and attached to an inner surface side of a window glass surface or a portion made of an insulating material.

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

  The operation of the present invention will be described below.

  In the antenna according to the embodiment of the present invention, as the ground side element 20, the ground side first element 21 extending so as to surround the hot side element 10 clockwise from the ground side feed point 7, and the left side from the ground side feed point 7. A shape that surrounds the hot side element 10 by overlapping the tip portions of the two wires with the ground side second element 22 extending so as to surround the hot side element 10 so as to be capacitively coupled to each other. It was made into the loop shape which has the opening part. For this reason, since the tip of the ground side first element 21 and the tip of the ground side second element 22 are opened, the impedance of the ground side can be adjusted by adjusting the length of the overlapping wire of each wire. Easy to adjust.

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

  Since the hot-side element 10 is surrounded by the open-loop shaped ground-side element 20, the electric field at the tip of the antenna that is susceptible to external influences can be stabilized, and the adjacent conductor (for example, the human body) can be stabilized. The influence can be reduced.

  The antenna according to the embodiment of the present invention regards the ground side element 20 as a ground antenna by setting the total length of the loop-shaped filaments of the ground side element 20 to 1 to 2 wavelengths of transmission / reception radio waves. Therefore, it is possible to obtain the same characteristics as the configuration in which the metal body is grounded at the frequency of the terrestrial digital broadcast wave band.

  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 of the first embodiment, a hot-side feeding point 6 is provided in the vicinity of the upper side near the upper left corner of the opening of the metal flange 3, connected to the hot-side feeding point 6, and substantially perpendicular to the lower side away from the upper side of the metal flange. And a ground side element 20 extended from the ground side feed point 7 provided in the vicinity of the hot side feed point 6.

  The ground-side element 20 includes an inverted U-shaped ground-side first element 21 extending from the ground-side feed point 7 so as to surround the hot-side element 10 clockwise around the hot-side element 10, and a ground-side feed point. The two elements of the U-shaped ground side second element 22 extending in the direction surrounding the hot side element 10 counterclockwise from 7 are opposed to each other so that the two ground side elements are capacitively coupled. The wires at the tips of the side elements are arranged close to each other so that the ground side element 20 surrounds the hot side element 10, and the tips of the elements constituting the ground side element 20 are opened. It has a substantially rectangular loop shape.

  In the antenna of the first embodiment, the ground side element 20 is branched from the ground side feed point 7 through the lead wire 26 to the ground side first element 21 and the ground side second element 22 from the tip, and the wires are opposite to each other. Extending the article.

  Examples of the length of each line of the antenna according to the first embodiment are as follows. The length of the filament from the hot-side feeding point 6 to the tip of the hot-side element 10 is ¼ wavelength of the radio wave at a substantially center frequency of 600 MHz of transmission / reception frequency, and the wavelength reduction rate (about 0.6) of the glass plate 1 To 60 mm.

  The length of the horizontal line extending to the right side from the upper end of the lead line 26 connected to the ground side feed point of the first element 21 on the ground side is 50 mm, the vertical line extending downward from the tip is 85 mm, and the vertical line The length of the folded line that is folded back in a U-shape from the lower end is 90 mm.

  The length of the horizontal line extending from the upper end of the lead line 26 connected to the ground side feeding point of the ground side second element 22 to the left side (corner direction) is 100 mm, and the vertical line extending downward from the tip is 90 mm, and the length of the folded line folded back in a U shape from the lower end of the vertical line is 95 mm.

  Furthermore, the length (A in FIG. 1) in which the folded line of the ground side first element 21 and the folded line of the ground side second element 22 overlap is 35 mm, and the interval between the lines is 5 mm.

  The distance between each horizontal line of the ground side first line 21 and the ground side second line 22 and the upper side of the flange opening is 5 mm, and the vertical line of the ground side second line 22 and the vertical direction of the flange opening are The distance from the side was 10 mm.

  The hot-side feed point 6 and the ground-side feed point 7 were each 10 mm in length and width, and the interval between the feed points was 15 mm.

  The antenna of the present embodiment is formed by printing a width of each line 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, and drying and baking in a heating furnace. The center conductor of the coaxial cable (not shown) extending from the tuner (not shown) was connected to the hot-side feeding point 6 and the outer conductor was connected to the ground-side feeding point 7.

  The terrestrial digital television broadcast wave receiving antenna of Example 1 created in this manner was provided in the vicinity of the upper corner of the rear window glass of the automobile, and received radio waves in the terrestrial digital television broadcast wave band having a frequency of 470 to 710 MHz. However, as shown by the thick solid line in FIG. 6, a good frequency characteristic with an average gain of −6.8 dB is obtained, and the average of the antenna of Comparative Example 1 described later (see FIG. 7) indicated by the thin solid line in FIG. A gain of −7.6 dB, and a band of 500 to 590 MHz and a band of 620 to 710 MHz, compared to an average gain of −7.6 dB of an antenna (see FIG. 8) of Comparative Example 2 described later shown by a dotted line in FIG. Thus, the reception gain is improved, and at least frequency characteristics equivalent to or higher than those of Comparative Examples 1 and 2 are obtained.

  Further, the antenna of the first embodiment shown in FIG. 1 obtained in this way has a simple configuration with little change in antenna impedance due to the human body even when a person is in the vehicle. Therefore, an antenna that does not impair the field of view can be provided, the reception 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. In the antenna of the second embodiment, unlike the first embodiment, the U-shaped ground side first element 21 and the reverse U-shaped ground side second element 22 of the ground side element 20 are connected to the ground side feeding point 7. Three horizontal filaments of the ground side first element 21 to be connected were used, and the tips of the three horizontal filaments were connected by vertical filaments. Moreover, the horizontal line of the earth side 2nd element 22 connected to the earth side feed point 7 was made into four, and each front-end | tip of these four horizontal lines was connected by the vertical line. Furthermore, the auxiliary filament 12 refracted in the horizontal direction from the lower end of the hot filament 11 of the hot element 10 is provided. . The rest is the same as in the first embodiment.

  In addition, Example 2 is characterized in that there are a plurality of horizontal filaments of the ground-side first element 21 and the ground-side second element 22 and a feature in which auxiliary filaments 12 that are bent and extended from the hot-side filament 11 are provided. However, these two features may be combined with the antennas of other embodiments separately.

  When the terrestrial digital television broadcast wave receiving antenna according to the second 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 can be obtained.

  Further, the antenna of the second embodiment shown in FIG. 2 obtained in this way has a simple configuration with little change in antenna impedance even when a person is on the vehicle, and has a simple structure. The antenna can be provided without damaging the antenna, the gain is high, the antenna tuning is easier than the conventional one, and it can be sufficiently put into practical use.

[Example 3]
The antenna of the third embodiment shown in FIG. 3 is different from the first embodiment in that the shape of the upper left corner of the ground side element is a substantially quarter arc shape, and is the same as the first embodiment in other points. .

  The antenna according to the third embodiment is provided in a round shape along the round shape of the upper corner of the opening of the window glass flange, and the hot-side feeding point 6 and the ground-side feeding point 7 are connected to the upper left arc-shaped corner. This is an example of juxtaposition in the vicinity.

  The antenna of the third embodiment is different from the first embodiment described above in that the ground side element has a U-shape extending from the ground side feeding point 7 so as to surround the hot side element 10 clockwise around the hot side element 10. Two elements of a ground-side first element 21 and an inverted U-shaped ground-side second element 22 partially having an arc portion extending so as to surround the hot-side element 10 counterclockwise from the ground-side feeding point 7. The end portions of the two elements are opposed to each other, and the filaments of the respective 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 hot side element 10, The tip of each element constituting the element 20 was open, and the upper left corner was a substantially rectangular loop shape with a quarter arc shape.

  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 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 can be obtained.

  Further, the antenna shown in FIG. 3 obtained in this way has almost no change in the antenna impedance even when a person is in the vehicle, and it has a simple configuration, which may impair visibility. Antennas can be provided, gain is high, and antenna tuning is easier than conventional ones.

[Example 4]
The fourth embodiment of the present invention shown in FIG. 4 is different from the first embodiment in that the shape of the ground side element is substantially circular, and the hot side element 10 is the same.
The earth-side element 20 has a right-side ellipse (or circle, oval) -shaped earth-side first extending from the earth-side feeding point 7 so as to surround the hot-side element 10 clockwise around the hot-side element 10. The element 21 and two elements of the earth-side second element 22 in the left half of the ellipse (or circle, oval) shape extending in the direction surrounding the hot-side element 10 counterclockwise from the ground-side feeding point 7 The tip end portions face each other, the arc strips at the tip ends of the two elements are closely overlapped so as to be capacitively coupled to each other, and are arranged so as to surround the hot side element 10, 20 differs from the first embodiment in that it has a substantially circular shape in which a tip of each element 20 is open.

  When the terrestrial digital television broadcast wave receiving antenna according to the fourth 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 can be obtained.

  In addition, the antenna shown in FIG. 4 obtained in this way has a simple configuration with almost no change in antenna impedance even when a person is in the vehicle, and the visual field is impaired. Antennas can be provided, gain is high, and antenna tuning is easier than conventional ones.

[Example 5]
The fifth embodiment of the present invention shown in FIG. 5 is a modified pattern of the first embodiment, which is different from the first embodiment described above. The substantially rectangular element of the ground side element 20 is replaced with an L-shaped ground side first. A part of each of the element 21, the reverse U-shaped ground side second element 22, and the L-shaped auxiliary line 23 are overlapped in close proximity so as to be capacitively coupled to each other. A substantially rectangular loop shape in which the tip of each element constituting the ground side element 20 is open is provided so as to surround the element. The hot side element 10 is the same as that of the first embodiment.

  The ground-side first element 21 is an L-shaped element that is connected to the ground-side feeding point 7 via a lead wire 26 and is composed of a horizontal wire extending to the right and a vertical wire extending downward from the tip. is there. The ground-side second element 22 is an inverted U-shaped element composed of a horizontal wire, a vertical wire, and a folded wire connected to the ground-side feeding point 7 through the lead wire 26 as in the first embodiment. . Further, an L-shaped auxiliary wire 23 is provided between the ground side first element 21 and the ground side second element 22, and between the one end of the auxiliary wire 23 and the ground side first element 21, and the auxiliary wire 23. Between the other end and the second element 22 on the ground side, 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 can be obtained.

  In addition, the antenna shown in FIG. 5 obtained in this way has a simple configuration with little change in antenna impedance due to the human body even when a person is on the vehicle, and thus impairs the field of view. An antenna can be provided, the gain is high, and the antenna tuning is easier than the conventional one.

[Comparative Example 1]
Comparative Example 1 shown in FIG. 7 is an antenna having a pattern described in Patent Document 1, and a substantially rectangular closed-loop earth-side element 20 ′ is provided so as to surround the hot-side element 10 ′ extending in the vertical direction. An antenna provided. The earth side element 20 ′ is connected to the earth side feeding point 7 ′ via a lead wire 26 ′.

  The line length of the hot-side 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, and the wavelength reduction rate of the glass plate 1 ′ is about 0.6. , 60 mm, and the length of the vertical side of the ground side element 20 ′ is 90 mm, and the length of the horizontal side is a substantially rectangular shape of 150 mm.

  The distance between the upper side of the ground side element 20 ′ and the upper side of the opening of the flange 3 ′ is 5 mm, and the distance between the vertical line of the ground side element 20 ′ and the vertical side of the opening of the flange 3 ′ is 10 mm. is there.

  The hot-side feeding point 6 ′ and the ground-side feeding point 7 ′ have a square shape of 10 mm in length and width, and the interval between the feeding points 6 ′ and 7 ′ is 15 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 -7.6 dB.

  According to the frequency characteristic diagram of FIG. 6, the antenna of Comparative Example 1 has a lower gain than the antenna of Example 1 in the 500 to 590 MHz band and the 620 to 710 MHz band. Further, since the antenna pattern of the closed loop shape of the comparative example 1 has a closed loop shape, it is not easy to adjust because it cannot be adjusted 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 ground side first element 21 ″ extending so as to surround the hot side element 10 ″ clockwise from the ground side feed point 7 ″ and a ground side feed point 7 ″. Two lines of an inverted U-shaped ground side second element 22 "extending so as to surround the hot side element 10" in a counterclockwise direction are arranged in a substantially rectangular shape, but the ground side second element 22 " The end is bent downward before the tip of the ground side first element 21 "so that the tips of the ground side first element 21" and the ground side second element 22 "do not overlap each other (ie, In this pattern, the first ground element 21 ″ and the second ground element 22 ″ are not coupled to each other in an open and substantially rectangular loop shape. The end of the wire of the ground side second element 22 ″ is bent downward so that the total length of the ground side second element 22 ″ matches the total length of the ground side second element 22 (see FIG. 1) of the first embodiment. This is to make it happen. The ground side first element 21 "and the ground side second element 22" are connected to the ground side feed point 7 "via a lead wire 26". The hot side element 10 "is connected to the hot side feeding point 6".

  The lengths of the vertical and horizontal sides of the substantially rectangular portion of the ground side element 20 ″ of the antenna 2 ″ of Comparative Example 2 are the same as the lengths of the vertical sides of the ground side elements of Comparative Example 1 and Example 1. The length of the side is 90 mm, the length of the lateral side is 150 mm, and the length of the portion bent downward on the ground side second element 22 ″ before the tip of the ground side first element 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, it is shown by a dotted line in FIG. Frequency characteristics were obtained, and the average reception gain was -7.6 dB.

  The frequency characteristic of the antenna of Comparative Example 2 is compared with the frequency characteristic of the antenna of Example 1 shown by the thick solid line in FIG. 6, in the band of 470 to 500 MHz, the band of 540 to 580 MHz, and the band of 620 to 710 MHz. The reception gain is lower than that in the first embodiment.

  Thus, when the antenna of the comparative example 2 and the antenna of the first embodiment are compared, in the antenna of the comparative example 2, the loop of the ground side first element 21 ″ and the ground side second element 22 ″ of the ground side element 20 ″ is looped. Since the overlap portion is not provided in the opening of the shape, the reception gain is reduced as compared with Example 1. In the antenna of Example 1, the reception gain is reduced by overlapping two elements on the ground side. You can avoid it.

  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 "Hot side feeding point 7, 7', 7" Earth side feeding point 10, 10 ', 10 "hot side element 11 hot side line 12 auxiliary line 20, 20', 20" ground side element 21 ground side first element 22 ground side second element 23 auxiliary line 24

Claims (10)

An antenna composed of a hot-side element and a ground-side element, disposed on a vehicle window glass,
The hot side element includes a wire connected to a hot side feeding point and extending in a direction away from the body flange,
The ground side element includes a ground side first element extending clockwise from the ground side power supply point provided in the vicinity of the hot side power supply point and a ground side second element extending counterclockwise from the ground side power supply point. Including
The ground-side element is in a loop shape having an opening so as to surround the hot-side element when each tip of the ground-side first element and the ground-side second element is electrically connected at high frequency. An antenna for a vehicle.   By disposing the tip portions of the ground side first element and the ground side second element close to each other so as to be capacitively coupled to each other on the side facing the ground side feeding point side, 2. The vehicle antenna according to claim 1, wherein the ground side first element and the ground side second element are electrically connected in a high frequency manner. An auxiliary wire is provided between the ground side first element and the ground side second element,
The auxiliary wire is disposed at a position where one end thereof is capacitively coupled with the tip of the ground side first element, and the other end is capacitively coupled with the tip of the ground side second element. Is located close to
2. The vehicle antenna according to claim 1, wherein the ground side first element and the ground side second element are electrically connected to each other at a high frequency, and the ground side element forms a loop wire.   The length of the part which mutually adjoins the other filament at the front-end | tip of the said ground side 1st element and the front-end | tip of the said earth side 2nd element is 10 mm to 1 wavelength, It is characterized by the above-mentioned. 4. The vehicle antenna according to 3.   5. The vehicle antenna according to claim 1, wherein a length of the hot side element is substantially a quarter wavelength of a transmission / reception radio wave.   The vehicular antenna according to any one of claims 1 to 5, further comprising an auxiliary filament that bends and extends from a tip of the hot-side element.   The vehicular antenna according to any one of claims 1 to 6, wherein an electrical length of the ground side element is 1 to 2 wavelengths of transmission / reception radio waves.   The one side connected to the earth side feeding point of the earth side first element is constituted by a plurality of parallel filaments, and tips of the plurality of filaments are connected to each other. The antenna for vehicles as described in any one.   The one side connected to the ground-side feeding point of the ground-side second element is constituted by a plurality of parallel filaments, and tip portions of the plurality of filaments are connected to each other. The vehicle antenna according to any one of the above.   10. The vehicle antenna according to claim 1, wherein the vehicle antenna according to any one of claims 1 to 9 is directly printed on a window glass surface of a vehicle or a sheet on which the pattern is printed is attached.

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