WO2012020605A1

WO2012020605A1 - Antenna for vehicle

Info

Publication number: WO2012020605A1
Application number: PCT/JP2011/064296
Authority: WO
Inventors: 亮太佐藤
Original assignee: セントラル硝子株式会社
Priority date: 2010-08-12
Filing date: 2011-06-22
Publication date: 2012-02-16
Also published as: JP2012044254A

Abstract

Provided is an antenna configured by filaments disposed in a window of a vehicle, wherein the antenna is provided with: a first feeding point and a second feeding point which are adjacently placed; an inner-side filament which connects to either one of the two feeding points and extends in a direction away from a metallic flange; and an outer-side loop element including a first filament extending clockwise and a second filament extending counterclockwise which surround the inner-side filament in mutually separating opposite directions along the flange from each of the two feeding points, respectively; wherein for the outer-side loop element, each of the distal ends of the first filament and the second filament, respectively, are in communication for high frequencies so as to form a loop shape, having an aperture portion, which surrounds the inner-side filament.

Description

Vehicle antenna

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

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

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

In such terrestrial digital television broadcast wave transmission / reception, it is necessary to make the reception sensitivity particularly high compared to the transmission / reception of terrestrial analog broadcast, and therefore, an ungrounded antenna is often adopted as an antenna system.

For example, Japanese Patent Application Laid-Open No. 2005-229140 discloses a linear antenna disposed on a window glass surface of a moving body such as an automobile or a surface of an insulating member of a body, and 1 of transmission / reception radio waves extending from a first feeding point. A first element having a length of / 4 wavelength or 3/4 wavelength and a second feeding point in the vicinity of the first feeding point so as to surround the first element from the second feeding point A vehicular antenna having a closed loop-like second element having a length of one or more wavelengths of transmitted / received radio waves extended to is disclosed.

Japanese Patent Application Laid-Open No. 2007-53505 discloses an antenna having a 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, and includes a first feeding point and a second feeding point. A loop element having a length of one to two wavelengths of transmission / reception radio waves in which conductive wires are disposed from the first feeding point to the second feeding point, and from either one of the feeding points A first element having a length of ¼ wavelength to ¾ wavelength of the extended transmission / reception radio wave, and 1/16 to ¼ wavelength extended from the middle of the loop element to the outside of the loop element. A loop-shaped vehicular antenna including a second element having a length of 5 mm is disclosed.

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, which is easily affected by the outside, with the closed-loop ground-side element. It is made difficult to be affected by the antenna performance due to the above, and a suitable receiving sensitivity is obtained. However, when tuning the resonant frequency of the antenna by adjusting the impedance of the antenna, the length of the ground side element is closed loop, making it difficult to adjust the length compared to the open loop filament, and free tuning There was a problem that the degree became small.

In addition, the antenna described in Patent Document 2 is 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. Similar to the problem of, when tuning the resonant frequency of the antenna by adjusting the impedance of the antenna pattern, the length of the loop element is adjusted compared to the open loop. There is a problem that the degree of freedom of tuning becomes small.

An object of the present invention is to provide an antenna suitable for improving antenna performance and receiving terrestrial digital television broadcast waves.

That is, a typical embodiment of the present invention is an antenna constituted by a wire disposed in a window of a vehicle, and includes a first feeding point and a second feeding point that are arranged close to each other. An inner element connected to one of the two feeding points and extending away from the metal flange forming the opening of the window, and a reverse direction away from each other along the flange from each of the two feeding points An outer loop element including a first line extending clockwise to surround the inner element and a second line extending counterclockwise, the outer loop element including the first loop A vehicular door, wherein a loop shape having an opening so as to surround the inner element is formed by conducting high-frequency conduction between the distal ends of the wire and the second wire. It is a container.

According to one embodiment of the present invention, it is possible to make the antenna less susceptible to the antenna performance due to the antenna installation location or the human body.

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 includes a first feeding point 6 and a second feeding point 7 which are disposed in close proximity on the 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 including at least two lines, a clockwise line 21 arranged clockwise to surround the element and a counterclockwise line 22 arranged counterclockwise is provided.

The inner element 10 is an element including a line 11 extending from the second feeding point 7 in a direction away from the nearest opening side of the metal flange 3, and the outer loop element 20 having the outer loop shape according to the present embodiment is substantially the same. It is an element extended in the direction of dividing into two. In FIG. 1, an example in which the inner element 10 extends from the second feeding point 7 is shown, 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).

By providing an overlap portion 24 that is overlapped so that the tip portions of the clockwise wire 21 and the counterclockwise wire 22 that are folded back so that the tip portions face each other are close to each other, the two wire rods are provided. The outer loop element 20 was formed by the clockwise line 21 and the counterclockwise line 22.

Further, as the inner element 10, the first inner filament 11 is extended from one feeding point (the feeding point 7 in FIG. 1) toward the inner center of the loop element. However, as shown in FIG. The second inner filament 12 may be extended from one feeding point (the feeding point 6 in FIG. 2) in substantially the same direction as the first inner filament 11.

In addition, when providing two inner filaments, you may carry out capacitive coupling by making the 1st inner filament 11 and the 2nd inner filament 12 adjoin. 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 including the two lines of the clockwise line 21 and the counterclockwise line 22 is capacitively coupled to the tip of the clockwise line 21 and the tip of the counterclockwise line 22. 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 linear 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. 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 clockwise line 21 and the counterclockwise counterclockwise line 22 of the outer loop element 20 are stretched so that the end portions of the elements do not overlap, An auxiliary wire 23 is provided between the tip portions of the elements, and one end portion of the auxiliary wire 23 and the tip portion of the clockwise wire wire 21 are brought close to each other so as to be capacitively coupled. Overlap

portions

24 and 25 may be provided at a plurality of locations so that the other end portion and the tip end portion of the counterclockwise line 22 are close to each other so as to be capacitively coupled.

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 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.

The antenna shown in FIG. 4 has a feature of extending the auxiliary wire 13 orthogonal to the inner wire 11 of the inner element 10 and a feature of constituting a part of the outer loop element 20 in an arc shape. The two features may be applied separately to the antennas of other embodiments.

Further, in the overlap portion 24, the total length of each of the strips of the outer loop element 20 constituted by the clockwise strip 21 and the counterclockwise strip 22 is regarded as one strip and is totaled. (Electrical 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 (A in FIG. 1) 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 is a length of 10 mm to 1 wavelength. Good.

As described above, in the overlap portion 24, the length of the overlapping portion is set to 10 mm or more. When the overlap portion is less than 10 mm, the capacitive coupling becomes weak, and the clockwise line 21 and the counterclockwise line 22 are reduced. This is because the effect that can be regarded as a single filament is reduced. Further, the length of the overlapping portion is set to one wavelength or less, because when the length of the overlapping filament is set to one wavelength or more, preferable capacitive coupling can be obtained, but the filament is complicated. .

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 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 connect front-end | tip parts.

In addition, the number of horizontal lines provided on the clockwise line 21 and the counterclockwise line 22 may be other numbers (for example, two or four or more) instead of the three illustrated. Moreover, a plurality of filaments may be arranged in parallel on both the clockwise filament 21 and the counterclockwise filament 22, or a plurality of filaments may be arranged in parallel on one side. . Further, the number of parallel lines provided on the clockwise line 21 and the counterclockwise line 22 may be the same or different.

The antenna shown in FIG. 3 has a feature of providing two inner filaments and a feature of arranging a plurality of parallel filaments on the clockwise filament 21 and the counterclockwise filament 22. The two features may be applied separately to the antennas of other embodiments.

Furthermore, 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 formed 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. A part of the outer loop element 20 may be arcuate in accordance with the shape of the part. Although not shown, the outer loop element 20 may have a circular shape, an elliptical shape, a square shape, a rhombus shape, or a polygonal shape.

Note that an internal conductor and an external conductor of a coaxial cable (not shown) are connected to the first feeding point 6 and the second feeding point 7, respectively.

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 conducts the antenna pattern on the window glass surface such as the upper margin, the lower margin, the front window glass, the side window glass, and the roof window glass of the heating filament of the rear window glass. It may be printed directly with an adhesive paste, or may be printed on a transparent seal or transparent sheet having a small thickness and adhered to a portion made of an insulating material or on the inner side of the window glass surface.

Further, the antenna 2 may be provided only at one location on the window glass of the automobile. However, the antenna is provided at a plurality of locations on the same window glass or at each of the plurality of window glasses, and diversity is achieved by using these antennas. You may receive. 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.

Hereinafter, the operation of the embodiment of the present invention will be described.

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 tip of the clockwise wire 21 and the tip of the counterclockwise wire 22 are open, the influence on the frequency characteristics is minimized by adjusting the length of the overlapped portion of each wire. While limiting, the impedance on the outer loop element 20 side can be easily adjusted, and the tuning of the antenna can be facilitated.

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 outer antenna element as shown in FIG. A reception characteristic equivalent to that of a conventional antenna having a loop element in a closed loop shape can be obtained. That is, an antenna that has a simple configuration and does not impair the field of view can be provided.

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 can be reduced. In addition, it is possible to make it less susceptible to the antenna performance due to the antenna installation location or the human body. Therefore, it is possible to obtain an antenna with stable characteristics in which the antenna impedance hardly changes depending on whether or not a person is in the vehicle.

Hereinafter, various embodiments of the present invention will be described.

[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.

The antenna according to the first embodiment includes a first feeding point 6, a second feeding point 7, and a second feeding point 7 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 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, respectively. And an outer loop element 20 having two lines of 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.

In addition, an overlap portion 24 is provided in which the end portions of each wire are overlapped in close proximity so that the two elements of the clockwise wire 21 and the counterclockwise wire 22 are capacitively coupled to each other. An outer loop element 20 is disposed so as to surround the element 10, and the outer loop element 20 is formed into a substantially rectangular loop shape in which the tips of the

elements

21 and 22 are opened.

The wire lengths of the antenna of Example 1 are 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 Is 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 further from the lower end of the vertical line. The length of the folded line that is folded back in a letter shape is 70 mm.

In addition, 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 further vertical. The length of the folded line folded back in a U shape from the lower end of the line 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 interval between the 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 vertical line of the counterclockwise line 22 and the vertical side of the flange opening are The interval is 10 mm.

The first feeding point 6 and the second feeding point 7 have a rectangular shape with a length of 10 mm and a width of 15 mm, respectively, and the interval between the feeding points is 5 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 central conductor of a coaxial cable (not shown) connected to a tuner (not shown) was connected to the second feeding point 7 and the outer conductor was connected to the first feeding point 6.

When the terrestrial digital television broadcast wave receiving antenna of the first 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 thick solid line in FIG. As shown in the figure, a favorable frequency characteristic with an average gain of −7.0 dB is obtained, and an average gain −8.1 dB of an antenna of Comparative Example 1 (see FIG. 7) described later shown by a thin solid line in FIG. Compared with the antenna of Comparative Example 2 (see FIG. 8) described later with reference to the dotted line in FIG.

Further, the antenna according to the first embodiment can provide 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, and has a high gain. Tuning is also 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 described above, the first feed point 6 is substantially parallel and in the same direction as the first inner filament 11 of the inner element 10 extending from the second feed point 7. The second embodiment is different from the first embodiment in that the second inner filament 12 is extended, and the first inner filament 11 and the second inner filament 12 are brought close to each other and capacitively coupled. Since other configurations are the same as those in the first embodiment, the same reference numerals are given to the same configurations, and descriptions thereof are omitted.

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 a coaxial cable (not shown) extending from a tuner (not shown) 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. As in the first embodiment, the central conductor of the coaxial cable may be connected to the second feeding point 7 and the outer conductor may be connected to the first feeding point 6. This is because the antenna of the second embodiment has the two

inner filaments

11 and 12, so that characteristics close to a balanced type can be obtained.

When the terrestrial digital television broadcast wave receiving antenna of the second 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 first embodiment. A good reception performance was obtained.

Further, the antenna of the second embodiment can provide an antenna that does not impair the field of view because it has a simple configuration with little change in antenna impedance due to the human body even when a person is in the vehicle. The antenna tuning is also easier than the conventional one.

[Example 3]
Example 3 is a modified pattern of Example 2 as shown in FIG. Unlike the second embodiment described above, the antenna of the third embodiment has three horizontal wires connected to the second feeding point 7 of the U-shaped clockwise wire 21 of the outer loop element 20, and the three The ends of the horizontal filaments were connected by vertical filaments. Similarly, the horizontal line 21 of the clockwise line 21 connected to the first feeding point 6 of the counterclockwise line 22 having an inverted U-shape is assumed to be three, and the ends of the three horizontal lines are perpendicular to each other. Connected by article.

Also, the number of counterclockwise wires 22 connected to the first feeding point 6 is three, and the tips of the three horizontal wires are connected by vertical wires. Since other than this is the same as that of the second embodiment, the same components are denoted by the same reference numerals, 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, the radio wave of the terrestrial digital television broadcast wave having a frequency of 470 to 710 MHz is received. Receiving performance was obtained.

Further, the antenna according to the third embodiment can provide an antenna that has almost no change in antenna impedance due to the human body and does not impair the field of view even when a person is on the vehicle, and has a reception gain. The antenna tuning is also easier than the conventional one.

The antenna of the third embodiment is obtained by adding a plurality of horizontal filaments to the antenna of the second embodiment. However, a modification in which a plurality of horizontal filaments is added to the antenna of the first embodiment is also included in the scope of the present invention. It is.

[Example 4]
The antenna of Example 4 shown in FIG. 4 is refracted horizontally from the point that the shape of the upper left corner of the outer loop element is a substantially quadrant arc shape and the lower end of the inner filament 11 of the inner element 10. Unlike the first embodiment, the auxiliary line 13 is the same as the first embodiment in the 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 a part of an arc extending so as to surround the inner element 10 counterclockwise from the first feeding point 6; The tip portions of the two elements face each other, and the filaments of the tip 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 forms a substantially rectangular loop shape in which the ends of the 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 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 reception performance was obtained.

Further, the antenna according to the fourth embodiment can provide an antenna that does not impair the field of view because the antenna impedance hardly changes even when a person is in the vehicle, and has a simple configuration, so that the reception gain can be reduced. The antenna tuning is also easier than the conventional one.

The antenna of the fourth embodiment has a feature in which the auxiliary wire 13 is added to the antenna of the first embodiment and a feature in which a part of the outer loop element 20 is formed in an arc shape. Modifications separately applied to the antennas of other embodiments are also included in the scope of the present invention.

[Example 5]
A fifth embodiment of the present invention shown in FIG. 5 is a modification pattern of the first embodiment, and the substantially rectangular outer loop element 20 is connected to an L-shaped clockwise line 21 and an inverted U-shaped counterclockwise. A part of each of the filaments 22 and the inverted L-shaped auxiliary filaments 23 are overlapped in close proximity so as to be capacitively coupled to each other, and are arranged so as to surround the inner element 10, so that the outer loop element It was set as the substantially rectangular loop shape with the front-end | tip of each filament which comprises 20 opened. In addition, since the structure of the inner element 10 is the same as Example 1 mentioned above, 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 that is connected to the second feeding point 7 and includes 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 Example 1, and includes a horizontal line extending to the left side, a vertical line extending downward from the tip, and a folded line that is folded back. Inverted U-shaped elements.

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, there are provided overlapping

portions

24 and 25 that are close to each other 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 reception performance was obtained.

Further, the antenna according to the fifth embodiment can provide an antenna that does not impair the field of view because it has a simple configuration with little change in antenna impedance due to the human body even when a person is on the vehicle. 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 2, and an inner element 10 ′ extending in the vertical direction from the second feeding point 7 ′ among the two neighboring feeding points, and , An antenna having a substantially rectangular closed loop outer loop element 20 ′ connecting two feeding points 6 ′ and 7 ′ so as to surround the inner 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 a rectangular shape with a longitudinal side of 10 mm and a lateral side of 15 mm, respectively, and the spacing 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 characteristics 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 has a band of 525 to 580 MHz, which 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. In the 615 to 710 MHz band, the gain is lower than that of 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 strip 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 a counterclockwise line 22 "having an inverted U shape extending so as to surround the inner element 10" in a counterclockwise direction are arranged, but the counterclockwise line 22 " Is bent downwardly 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 (ie, This is a pattern having an open substantially rectangular loop shape in which the clockwise 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 ″ extending 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, and the length of the horizontal side is 130 mm. The length of the portion 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, it is shown by a 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 compared with the frequency characteristic of the antenna of Example 1 shown by the thick solid line in FIG. In the 580 MHz band and the 580 to 710 MHz band, the reception gain is considerably lower than that in the first embodiment.

Thus, when the antenna of the comparative example 2 and the antenna of the first example are compared, the antenna of the comparative example 2 includes the clockwise line 21 "and the counterclockwise line 22" of the outer loop element 20 ". Since the overlap portion is not provided in the loop-shaped opening, the reception gain is reduced by overlapping the two filaments in the opening.

Although the present invention has been described in detail with reference to the accompanying drawings, the present invention is not limited to such specific configurations, and various modifications and equivalents within the spirit of the appended claims Includes configuration.

This application claims the priority of Japanese Patent Application No. 2010-180962 filed on August 12, 2010, and is incorporated into the present application by referring to its contents.

Claims

An antenna constituted by a wire disposed in a window of a vehicle,
A first feeding point and a second feeding point that are arranged close to each other;
An inner element connected to one of the two feeding points and extending away from the metal flange forming the opening of the window;
An outer side including a first line extending clockwise and a second line extending counterclockwise so as to surround the inner element in opposite directions away from each other along the flange from each of the two feeding points. A loop element,
The outer loop element forms a loop shape having an opening so as to surround the inner element by conducting high-frequency conduction between the tip ends of the first and second filaments. An antenna for a vehicle.
By disposing the tip portion of the first filament and the tip portion of the second filament at positions close to each other so as to be capacitively coupled to each other, the first filament and the second filament Is conductive at high frequencies,
The vehicular antenna according to claim 1, wherein the capacitive coupling portion is provided on a side facing the side of the outer loop element on the side where the two feeding points are provided.
The length of the part where the tip of the first filament and the tip of the second filament are close to each other is 10 mm to one wavelength of transmitted / received radio waves. Vehicle antenna.
A first auxiliary filament is provided between the first filament and the second filament,
The first auxiliary filament is disposed at a position where one end of the first auxiliary filament is close to the tip of the first filament and capacitively coupled, and the other end is connected to the tip of the second filament. Placed in close proximity to join,
2. The vehicle according to claim 1, wherein the first wire and the second wire are electrically connected in a high-frequency manner, and the outer loop element forms a loop shape having an opening. Antenna.
The length of the portion where the tip of the first filament and one end of the first auxiliary filament are close to each other, and the other end of the second filament and the first auxiliary filament 5. The vehicle antenna according to claim 4, wherein the length of the portion close to the end is from 10 mm to one wavelength of transmitted / received radio waves.
2. The vehicle antenna according to claim 1, wherein the length of the inner element is substantially a quarter wavelength of the transmitted / received radio wave.
The vehicular antenna according to claim 1, 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 in close proximity and parallel to the first inner element so as to be capacitively coupled to the first inner element;
The vehicular antenna according to claim 1, wherein the second inner element is extended from a feeding point different from a feeding point to which the first inner element is connected.
The vehicular antenna according to claim 1, wherein the electric length of the outer loop element is 1 to 2 wavelengths of transmission / reception radio waves.
2. The vehicle according to claim 1, wherein a portion connected to the feeding point of the first filament is constituted by a plurality of parallel filaments, and both ends of the plurality of filaments are connected to each other. antenna.
2. The vehicle according to claim 1, wherein a portion connected to a feeding point of the second filament is constituted by a plurality of parallel filaments, and both end portions of the plurality of filaments are connected to each other. Antenna.
The vehicle antenna according to claim 1, wherein the vehicle antenna according to claim 1 is directly printed on a window glass surface of a vehicle, or a sheet on which the pattern is printed is attached.