JP2007158612A - Pole antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pole antenna capable of ensuring stable transmission/reception performance when a car is running at a very high speed. <P>SOLUTION: The pole antenna 10 consists of an oblong base 13; a first antenna element 11 provided on the base 13; and a second antenna element 12 provided on the tip of the first antenna element 11, so as to be perpendicular to the longitudinal direction of the base 13, and in parallel to the installation surface of the base 13. The first antenna element 11 and the second antenna element 12 are configured so that an angle for the element 11 to be formed for the base 13, and an angle for the element 12 to be formed for the first antenna element 11 can be varied. This pole antenna is used as a pole antenna 10R provided on the right and left upper parts of a rear window shield and having directivity in the rear, and a loop antenna 10F having directivity in the front is provided on the right and left upper parts of a front window shield. This configuration can form a receiver capable of selecting and outputting good-sensitivity radio waves. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pole antenna, and more particularly to a pole antenna suitable for receiving a terrestrial digital television broadcast in an automobile.

  2. Description of the Related Art Conventionally, a vehicle (moving body) such as an automobile is equipped with an antenna that enables reception of radio waves while moving. The radio waves received by vehicles have been mainly AM radio wave (MW), FM radio and TV ultra-high frequency (VHF) and ultra-high frequency (UHF) for many years. An antenna for transmitting and receiving a radio wave in a high frequency band such as an antenna for (Earth Positioning System) and an antenna for receiving terrestrial digital broadcasting is becoming necessary for vehicles. Furthermore, antennas that transmit and receive radio waves are also required for radio beacons of ETC (automatic tollgate system) and VICS (road traffic information communication system).

  When these antennas are attached to a moving vehicle, it is generally performed that the antenna is formed on a transparent film and the transparent film antenna is attached to a glass such as a windshield of the vehicle. Yes.

  For example, Patent Document 1 discloses a technique in which such a transparent film antenna is attached to a glass such as a windshield of an automobile. The antenna described in Patent Document 1 is an integrated antenna in which a GPS antenna, a satellite digital broadcast antenna, an ETC antenna, a TV broadcast antenna, and the like are formed on a transparent film. A plurality of antenna elements are formed of ink or conductive foil.

  And most of the conventional vehicle-mounted antennas were designed with the aim of non-directionality in a horizontal plane.

JP-A-2005-102183

  However, like conventional in-vehicle antennas, omnidirectional antennas in the horizontal plane may deteriorate the reception distribution due to the effects of multipath when the car is moving at high speed, depending on the modulation method of radio waves to be transmitted / received, resulting in poor transmission / reception performance. There was something to do. For example, in an analog TV broadcast receiver, if the reception performance decreases, noise increases and the image quality only deteriorates. However, in a digital TV broadcast receiver, if the reception performance decreases, the images are interrupted and become invisible. There has been a problem that the deterioration of the reception performance is noticeable.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a pole antenna that can ensure stable transmission / reception performance even when a vehicle is moving at a high speed and that does not protrude rearward of the vehicle and has a good appearance.

  The pole antenna of the present invention that achieves the above object can take the following nine forms.

  The first form includes a base having an installation surface attached to the antenna installation site, a first antenna element protruding from the base, and a second antenna element at the tip of the first antenna element. In the pole antenna, the first antenna element is relative to the base and the second antenna element is relative to the first antenna element so that the second antenna element is parallel to the installation surface of the base. The pole antenna is configured so that the angle formed can be varied.

  The second form is the pole antenna of the first form, wherein the base is a first base having an installation surface attached to the antenna installation site, and a rotation provided in the longitudinal direction of the first base. A pole antenna comprising a second base swingable with respect to a first base by a shaft, wherein the first antenna element is attached to the second base.

  The third mode is a pole antenna according to the first mode, wherein the second antenna element is configured to be parallel to the installation surface of the base with the second antenna element rotated to the maximum from the first antenna element. This is a pole antenna.

  In the fourth form, in the pole antenna of the second form, the second base is swung with respect to the first base, the first antenna element is rotated with respect to the second base, A pole characterized in that the second antenna element is rotated relative to the first antenna element so that the second antenna element is parallel to the installation surface of the first base. It is an antenna.

  In the fifth embodiment, in the pole antenna according to any one of the first to fourth embodiments, the distance between the installation surface of the base and the second antenna element is set to 1 / 5.5 to 8.5 wavelengths of the reception frequency. The pole antenna is characterized in that it can be set to a length of.

  A sixth embodiment is a pole antenna according to any one of the first to fifth embodiments, wherein the second antenna element is set to a length of approximately ¼ wavelength of the reception frequency. is there.

  A seventh embodiment is a pole antenna according to any one of the first to sixth embodiments, wherein the width of the base in the longitudinal direction is set to a printed antenna installed on a rear glass of a vehicle, or a defogger print heater and a rear glass window. A pole antenna having a width that fits in a space between the frame and a base that is attached to the space.

  The eighth embodiment is a pole antenna according to any one of the first to seventh embodiments used for digital television broadcasting, wherein the distance between the installation surface of the base and the second antenna element is 4.5 to It is a pole antenna characterized by being 11.6 cm.

  A ninth form is a pole antenna according to any one of the first to eighth forms used for digital television broadcasting, and the second antenna element is set to a length of 10.5 cm to 16 cm. This is a pole antenna.

  As described above, according to the present invention, a stable transmission / reception performance can be ensured even when the automobile is moving at high speed, and a pole antenna that does not protrude rearward of the automobile and has a good appearance can be realized.

  Embodiments of a pole antenna according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 shows a sedan type automobile 100 provided with a rear antenna 4 having a pole antenna 10 according to an embodiment of the present invention. The rear glass 4 of the automobile 100 is generally provided with a defogger 7 for preventing fogging. The defogger 7 is configured by a heater element (heating wire) being stretched between electrodes provided on both sides of the rear glass 4, and the heater elements are arranged in a horizontal direction when viewed from the rear of the automobile 100. Is provided.

  In this embodiment, the pole antenna 10 is provided on the outer surface between the electrode of the defogger 7 provided on the rear glass 4 of the automobile 100 and the attachment frame of the rear glass door 4 to the vehicle body. Receive TV broadcasts. A coaxial cable 22 is connected to the pole antenna 10, and this coaxial cable 22 is connected to the TV tuner 5 installed below the rear seat of the automobile 100. The signal (image and sound) received by the TV tuner 5 is also input to the car navigation device 8 provided on the instrument panel 9 through the coaxial cable 22 and displayed when the car navigation device 8 is in the television mode. The received image is displayed on the instrument.

  FIG. 2 is a block circuit diagram showing the connection of the two pole antennas 10 of FIG. 1 to the navigation device 8. In the example shown in FIG. 1, the TV tuner 5 is separate from the navigation device 8, but in this example, the TV tuner 5 is built in the navigation device 8. When the pole antenna 10 is an antenna that receives terrestrial digital TV radio waves, a signal received by the pole antenna 10 is cabled through an integrated circuit 40 that is built in a base member (to be described later) of the pole antenna 10 and performs amplification or the like. 22, the image guided and demodulated by the TV tuner 5 is displayed on the display 6 when the navigation device 8 is in the television mode.

  In this embodiment, only the case where the pole antenna 10 is connected to the TV tuner 5 built in the navigation device 8 is shown, and illustration and description of other configurations of the navigation device 8 are omitted. This is because even if the pole antenna 10 is a GPS antenna or a satellite digital broadcasting antenna, the circuit up to the receiver is not much different from the circuit of this embodiment.

  The two pole antennas 10 shown in FIG. 1 are configured so that their antenna elements are parallel to the outer surface when attached to the outer surface of the automobile. Details of the configuration are shown in FIGS. 3 (a) and 3 (b). The pole antenna 10 of the first embodiment includes a base member 13 that is a base fixed to the outer surface of the automobile 100, and a first rotary shaft 14 that is rotatably attached to the base member 13 by a first rotating shaft 14. The antenna element 11 includes a first antenna element 11 and a second antenna element 12 that is rotatably attached to a distal end portion of the first antenna element 11 by a second rotating shaft 15.

  The base member 13 is formed in a vertically long shape, and a first rotating shaft 14 is provided in the vicinity of one end portion. The first rotating shaft 14 is provided in a direction orthogonal to the longitudinal direction of the base member 13, and the first antenna element 11 is rotated by the first rotating shaft 14 until reaching a predetermined angle with the base member 13. Can do. The second rotating shaft 15 is provided at the tip of the first antenna element 11, and is perpendicular to the second antenna element 12 with respect to a plane including the rotation locus of the first antenna element 11. Bend in the direction of.

  FIG. 4 shows an example of an attachment location when the pole antenna 10 shown in FIG. 3 is attached to the back door 19 of the hatchback type vehicle 100. First, an installation method when the pole antenna 10 is installed on the rear glass 4 provided on the back door 19 will be described.

  When the pole antenna 10 of the first embodiment is attached to the rear glass 4, the base member 13 described with reference to FIG. 3 is attached to the electrode of the defogger 7 provided on the rear glass 4 of the automobile 100 and the frame for attaching the rear glass door 4 to the vehicle body. Attach to the outer surface between. The attachment can be performed by an adhesive applied to the attachment surface of the base member 13. Next, the first antenna element 11 is rotated with respect to the base member 13 and pulled up, and then the second antenna element 12 is bent in a direction orthogonal to the first antenna element 11, and the second antenna element 12 is parallel to the heater element of the defogger 7.

  The pole antenna 10 of the first embodiment can be mounted on the rear glass 4 by the above procedure. In this case, the second antenna element 12 of the pole antenna 10 is parallel to the heater element of the defogger 7, and the heater element of the defogger 7 acts as a reflector with respect to the second antenna element 12 of the pole antenna 10. Become.

  On the other hand, the pole antenna 10 shown in FIG. 3 can be attached to the metal portion of the back door 19 of the hatchback type vehicle 100 excluding the rear glass 4. Similarly, when the pole antenna 10 of the first embodiment is attached to the back door 19, the base member 13 described with reference to FIG. 3 is attached to an arbitrary outer surface of the back door 19 of the automobile 100. The attachment can be performed by an adhesive applied to the attachment surface of the base member 13. Next, the first antenna element 11 is rotated with respect to the base member 13 and pulled up, and then the second antenna element 12 is bent in a direction orthogonal to the first antenna element 11, and the second antenna element 12 is parallel to the metal portion of the back door 19.

  The pole antenna 10 of the first embodiment can be attached to the metal portion of the back door 19 by the above procedure. In this case, the second antenna element 12 of the pole antenna 10 is parallel to the metal portion of the back door 14 of the automobile 100, and the metal portion of the back door 19 is connected to the second antenna element 11 of the pole antenna 10. On the other hand, it becomes a reflector.

  FIGS. 5A to 5C and FIGS. 6A to 6C show details of the configuration of the pole antenna 10 of the second embodiment of the present invention shown in FIG. 5A shows a state in which the pole antenna 10 is folded, and FIGS. 5B, 5C, 6A, and 6B show the operation of the pole antenna 10. FIG. FIG. 6C shows the pole antenna 10 as seen from the bottom surface side of the base member 13, that is, the installation surface side.

  The pole antenna 10 of the second embodiment shown in FIG. 5 and FIG. 6 is parallel to the longitudinal direction of the base member 13 on the bottom surface of the base member 13 of the pole antenna 10 of the first embodiment described in FIG. The mounting plate 16 supported by the third rotating shaft 17 is provided, and the configurations of the first and second antenna elements 11, 12 and the base member 13 are the same as those in the first embodiment. Accordingly, the first antenna element 11 is rotatably attached to one end of the base member 13 formed in a vertically long manner by the first rotating shaft 14, and the second rotating shaft 15 is attached to the distal end portion of the first antenna element 11. A second antenna element 12 is rotatably attached.

  As shown in FIGS. 5B and 6B, the first antenna element 11 is separated from the base member 13 by a first rotation shaft 14 at a predetermined angle (the angle shown in FIG. 6B is 60). Can be rotated until Further, as shown in FIGS. 5B, 6A, and 6B, the second antenna element 12 is perpendicular to the plane that includes the rotation locus of the first antenna element 11. Can be folded in the direction.

  Further, as shown in FIG. 6C, after the pole antenna 10 is attached to the metal portion of the back door 19 by the adhesive 18 applied to the attachment plate 16, the base member 13 is moved to the third rotating shaft. 17 can be rotated left and right. As a result, the first antenna element 11 and the second antenna element 12 are bent and then the base member 13 is rotated so that the second antenna element 12 is parallel to the metal portion of the back door 19. Can be adjusted as follows.

  In the pole antenna 10 of the second embodiment, the first to third rotating shafts 14, 15 and 17 are provided. Therefore, as shown in FIG. Even when the first antenna element 11 and the second antenna element 12 are bent, the base member 13 is rotated after the first antenna element 11 and the second antenna element 12 are bent. It can be adjusted to be parallel to the heater element of the defogger 7 provided in the above.

  In the above embodiment, the second antenna element 12 is preferably configured to have a length of ¼ wavelength of the reception frequency of the pole antenna 10. Further, when the reception frequency of the pole antenna 10 has a predetermined bandwidth, it has a length between ¼ wavelengths of the upper and lower limits of the bandwidth, preferably ¼ of the center frequency of the bandwidth. It is desirable that the wavelength be configured. Further, when the pole antenna 10 lifts the first antenna element 11 from the base member 13 and makes the second antenna element 12 parallel to the metal part of the back door 19 or the heater element of the defogger 7, the pole antenna 10 The distance from the metal portion to the second antenna element 12 or the distance from the heater element of the defogger 7 to the second antenna element 12 is configured to be 1 / 7.5 wavelength long of the reception frequency of the pole antenna 10. It is desirable that Further, when the reception frequency of the pole antenna 10 has a predetermined bandwidth, it is desirable that the length is 1 / 7.5 wavelength of the center frequency of the bandwidth.

  In the case of digital television broadcasting, the frequency band is 470 to 770 MHz, and there are many broadcast waves on the lower side of the frequency band, and the antenna characteristics are such that the upper side of the center frequency is gradually attenuated from the lower side. It has been confirmed by the applicant's experiment and the like that the center frequency is preferably 500 MHz. Thereby, 10.5 to 16 cm which is 1/4 of the wavelength 64 cm to 39 cm with respect to the frequency band 470 to 770 MHz is preferable as the second antenna element length, and in particular, 15 cm which is 1/4 of the wavelength 60 cm with respect to the frequency 500 MHz is the first. Two antenna element lengths are more preferable.

  The distance from the metal portion of the second antenna element is 1 / 5.5 to 1 / 8.5 of the wavelength 64 cm to 39 cm for the frequency band 470 to 770 Mhz, depending on the material and structure of the metal portion and the like. It has been confirmed by the applicant's experiment etc. that 4.5 to 11.5 cm is preferable, and that 7 to 11 cm which is 1 / 5.5 to 1 / 8.5 of a wavelength of 60 cm for a frequency of 500 MHz is particularly preferable. .

  When the pole antenna 10 configured as described above is attached to the rear glass 4 or the back door 19 of the automobile 100, the pole antenna 10 is formed by a reflector acting on the heater element of the defogger 7 or the metal part of the back door. Can efficiently receive incoming waves from the rear of the car. That is, the pole antenna 10 of this embodiment attached to the rear glass 4 of the automobile 100 or the back door 19 has directivity with respect to the rear of the automobile.

  On the other hand, when the loop antenna formed on the film sheet is attached above the windshield of the automobile, the loop antenna can have directivity with respect to the front of the automobile.

  Therefore, as one embodiment of the present invention, as shown in FIG. 8, the pole antenna 10 of any of the examples described above includes the rear glass 4 provided with the defogger 7, or the metal portion of the back door 19, In an automobile 100 including a TV tuner 5 and a car navigation device 8, a configuration in which a loop antenna 10 </ b> F formed on a sheet-like film is attached to the left and right upper portions of the windshield 1 and connected to the TV tuner 5 is possible. It is. In this embodiment, the pole antenna 10 attached to the rear glass 4 or the metal part of the back door 19 is referred to as a pole antenna 10R in order to distinguish the antennas.

  A coaxial cable 22 is connected to the two power supply terminals of the loop antenna 10F via a connector (not shown). The coaxial cable 22 is drawn out along the A pillar 3 of the automobile and connected to the TV tuner 5. It is assumed that this loop antenna 10F can also receive terrestrial digital television broadcasting. The signal (image and sound) received by the TV tuner 5 is also input to the car navigation device 8 provided on the instrument panel 9 through the coaxial cable 22 and displayed when the car navigation device 8 is in the television mode. The received image is displayed on the instrument.

  FIG. 9 is a block circuit diagram showing the connection of the two pole antennas 10R and the two loop antennas 10F of FIG. 8 to the navigation device 8. In the example shown in FIG. 8, the TV tuner 5 is separate from the navigation device 8, but in this example, the TV tuner 5 is built in the navigation device 8. When the pole antenna 10R and the loop antenna 10F are antennas that receive terrestrial digital television radio waves, signals received by the pole antenna 10R are connected to the cable 22 via the integrated circuit 40 that is built in the base member 13 and performs amplification or the like. The signal received by the loop antenna 10F and received by the loop antenna 10F is guided to the digital TV tuner 5 by the cable 22 via the integrated circuit 40 that is built in the connector and performs amplification or the like.

  The digital TV tuner 5 demodulates the input signals from the four antennas 10F and 10R (OFDM modulated signals in digital television broadcasting) as a good signal by combining processing such as maximum ratio combining. The demodulated image is displayed on the display 6 when the navigation device 8 is in the television mode.

  As a result, when receiving terrestrial digital TV radio waves with a non-directional antenna in a horizontal plane, such as a conventional in-vehicle antenna, the reception distribution deteriorates due to the effects of multipath when the automobile moves at high speed, and transmission / reception is performed. Although the performance was degraded, in the receiving apparatus of this embodiment having four antennas, when receiving a terrestrial digital TV radio wave, the TV tuner 5 selects the one with the highest electric field strength from the received signals. Therefore, stable transmission / reception performance can be ensured even when the automobile is moving at high speed.

1 is a perspective view of a sedan type automobile provided with a pole antenna according to an embodiment of the present invention on a rear glass. It is a block circuit diagram which shows the connection to the navigation apparatus of two pole antennas of FIG. (A) is a perspective view which shows the structure of the 1st Example of the two pole antenna of FIG. 1, (b) is a perspective view which shows operation | movement of the pole antenna shown to (a). FIG. 4 is a rear view of the vehicle showing an attachment position of the pole antenna shown in FIGS. 3A and 3B to a back door of a hatchback type vehicle. (A) is a perspective view which shows the structure of the 2nd Example of the two pole antenna of FIG. 1, (b), (c) is a perspective view which shows operation | movement of the pole antenna shown to (a). (A) is a plan view of the pole antenna shown in FIG. 5, (b) is a side view showing the operation of the pole antenna shown in (a), and (c) is a bottom view of the pole antenna shown in (a). is there. It is a fragmentary sectional view of a rear glass which shows the attachment state to the rear glass of the pole antenna of the 2nd Example of this invention. 1 is a perspective view of a sedan-type automobile that includes a pole antenna according to an embodiment of the present invention on a rear glass, a film antenna on a windshield, and a television receiver and a car navigation device. It is a block circuit diagram which shows the connection to the navigation apparatus of four antennas of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front glass 3 A pillar 4 Rear glass 5 TV tuner 7 Defogger 8 Car navigation apparatus 10, 10R pole antenna 10F Loop antenna 11 1st antenna element 12 2nd antenna element 13 Base member 14 1st rotating shaft 15 2nd Rotating shaft 16 Mounting plate 17 Third rotating shaft 18 Adhesive material 19 Back door 22 Coaxial cable 40 Integrated circuit 100 Automobile

Claims (9)

In a pole antenna comprising a base having an installation surface attached to an antenna installation site, a first antenna element projecting from the base, and a second antenna element at the tip of the first antenna element,
The first antenna element is in relation to the base and the second antenna element is in the first antenna element so that the second antenna element is parallel to the installation surface of the base. On the other hand, a pole antenna characterized in that the angle formed can be varied. The pole antenna according to claim 1,
The base has a first base having an installation surface attached to the antenna installation site, and a second swingable with respect to the first base by a rotation shaft provided on the first base. It consists of the base of
The pole antenna, wherein the first antenna element is attached to the second base. The pole antenna according to claim 1,
The pole antenna, wherein the second antenna element is configured to be parallel to an installation surface of the base in a state where the second antenna element is rotated to the maximum from the first antenna element. The pole antenna according to claim 2,
The second base is swung with respect to the first base, the first antenna element is rotated with respect to the second base, and the second antenna element is moved to the first base. A pole antenna, wherein the second antenna element is configured to be parallel to an installation surface of the first base by rotating with respect to the antenna element. The pole antenna according to any one of claims 1 to 4,
A pole antenna characterized in that a distance between an installation surface of the base and the second antenna element can be set to a length of 1 / 5.5 to 1 / 8.5 of a reception frequency. . The pole antenna according to any one of claims 1 to 5,
The pole antenna, wherein the second antenna element is set to a length of approximately ¼ wavelength of a reception frequency. The pole antenna according to any one of claims 1 to 6,
The width of the base in the longitudinal direction is formed to be a width that fits in a space between a printed antenna installed on a rear glass of a vehicle or a print heater for a defogger and the window frame of the rear glass. A pole antenna mounted in the space. The pole antenna according to any one of claims 1 to 7, which is used for digital television broadcasting,
A pole antenna, wherein a distance between an installation surface of the base and the second antenna element is 4.5 to 11.6 cm. The pole antenna according to any one of claims 1 to 8, which is used for digital television broadcasting,
The pole antenna, wherein the second antenna element is set to a length of 10.5 cm to 16 cm.

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