JP2006211292A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna device which can reduce cost, and attain miniaturization. <P>SOLUTION: In an antenna device which is provided with an antenna element (21) which has a receiving plane to receive a satellite wave or a terrestrial wave, a circuit board (23), and electronic components mounted on a rear plane of the circuit board; a ground pattern is formed on an upper plane of the circuit board (23). The receiving plane and the ground pattern of the antenna element (21) are installed in opposite sides placing a predetermined space. The antenna device (20) is provided with a metal cover (25) which works as an electromagnetic shield of the electronic components. Moreover, a feeding conductor (24) is arranged between the antenna element (21) and the ground pattern. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antenna device used for receiving radio waves of digital radio broadcasting.

  Recently, a digital radio receiver that can receive a digital radio broadcast by receiving a satellite wave or a ground wave has been developed and put into practical use in the United States. This digital radio receiver is mounted on a mobile station such as an automobile, and can receive radio waves by receiving radio waves having a frequency of about 2.3 GHz. That is, the digital radio receiver is a radio receiver capable of listening to mobile broadcasts. Since the frequency of the received radio wave is about 2.3 GHz, the reception wavelength (resonance wavelength) λ at that time is about 128.3 mm. The terrestrial wave is a satellite wave that is once received by the earth station, then slightly shifted in frequency, and retransmitted with linearly polarized waves.

  As described above, since radio waves having a frequency of about 2.3 GHz band are used in digital radio broadcasting, an antenna for receiving the radio waves must be installed outdoors. Therefore, when a digital radio receiver is mounted on a vehicle, the antenna must be attached to the roof of the vehicle. Such an automobile antenna and a receiver main body (head unit) installed in the interior of the automobile are electrically connected via a cable. The head unit operates as an external device.

  A reception system for receiving this type of satellite wave or terrestrial wave includes an antenna unit (antenna device) and a tuner unit (satellite radio tuner). The antenna unit (antenna device) receives a satellite wave or a ground wave and outputs a high-frequency reception signal. A tuner unit (satellite radio tuner) demodulates the received signal and outputs an audio signal.

  In a conventional receiving system, an antenna unit (antenna device) and a tuner unit (satellite radio tuner) are configured in a state of being separated from each other. In other words, the conventional antenna device is composed of an antenna element that receives a satellite wave or a terrestrial wave, and a low noise amplifier (LNA) that amplifies a radio wave received by the antenna element and outputs a received signal. Yes.

  On the other hand, the head unit is classified into a tuner-equipped head unit equipped with a satellite radio tuner and a tuner-unequipped head unit not equipped with a satellite radio tuner.

  1 and 2 show first and second conventional receiving systems, respectively. A first conventional receiving system 10A shown in FIG. 1 uses a tuner-mounted head unit 30A as a head unit. A second conventional receiving system 10B shown in FIG. The mounting head unit 30B is used.

  As shown in FIG. 1, the first conventional receiving system 10A includes an antenna device 20A and a tuner-mounted head unit 30A. The antenna device 20A and the tuner-mounted head unit 30A are connected via an RF coaxial cable 40A. The antenna device 20 </ b> A includes an antenna element 21 and a low noise amplifier (LNA) 22. The tuner-mounted head unit 30A is equipped with a satellite radio tuner 60A.

  As shown in FIG. 2, the second conventional reception system 10 </ b> B includes an antenna device 20 </ b> A, a tuner-uninstalled head unit 30 </ b> B, and a satellite radio receiver 50. The antenna device 20A and the satellite radio receiver 50 are connected via an RF coaxial cable 40A. The satellite radio receiver 50 and the tuner-uninstalled head unit 30B are connected via a bus cable 40B. The satellite radio receiver 50 is equipped with a satellite radio tuner 60A.

  For example, a planar antenna can be used as the conventional antenna device 20A (see, for example, Patent Document 1). The planar antenna disclosed in Patent Document 1 includes an upper case, a planar antenna element disposed at a predetermined interval on the back surface of the upper case, and a ground plate disposed at a predetermined interval from the planar antenna element. A power supply conductor disposed between the planar antenna element and the ground plate, a circuit board bonded to the lower surface of the ground plate, and an electronic component mounted on the circuit board. The electronic component includes the low noise amplifier (LNA) described above.

Japanese Patent Laid-Open No. 2001-24428

  In the conventional antenna device, it is necessary to provide a ground plate for antenna radiation separately from the circuit board. Therefore, it is difficult to reduce the cost of the antenna device, and it is difficult to reduce the size.

  Therefore, an object of the present invention is to provide an antenna device that can reduce costs.

  Another object of the present invention is to provide an antenna device that can be miniaturized.

  According to the present invention, an antenna element (21) having a receiving surface for receiving satellite waves or terrestrial waves, a circuit board (23), and an electronic component mounted on one surface (23b) of the circuit board ( 61 to 64), a ground pattern (231) is formed on the other surface (23a) of the circuit board, and the receiving surface of the antenna element and the ground pattern are spaced apart from each other by a predetermined distance. Thus, an antenna device can be obtained.

  The antenna device (20) according to the present invention may further include a metal cover (25) for electromagnetically shielding the electronic component. Moreover, you may further provide the electric power feeding conductor (24) arrange | positioned between the said antenna element (21) and the said ground pattern (231). The electronic component may include a tuner unit (61) that demodulates radio waves received by the antenna element and outputs an audio signal, and an interface unit (63) that converts the audio signal into a serial signal.

  In addition, the code | symbol in the said parenthesis is attached | subjected in order to make an understanding of this invention easy, and it is only an example, and of course is not limited to these.

  In the present invention, since the ground pattern is formed on the other surface of the circuit board, it is not necessary to provide a ground plate for antenna radiation separately from the circuit board, and the cost can be reduced and the size can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  With reference to FIG. 3, a reception system 10 to which an antenna device 20 according to an embodiment of the present invention is applied will be described.

  The illustrated receiving system 10 includes an antenna device 20 equipped with a satellite radio tuner 60 and a head unit 30 not equipped with a tuner, and the antenna device 20 and the head unit 30 not equipped with a tuner are connected via a serial bus cable 40. ing. The antenna device 20 has an antenna element 21.

  Referring to FIG. 4 in addition to FIG. 3, the satellite radio tuner 60 mounted on the antenna device 20 includes a satellite radio tuner unit 61, a digital demodulation unit 62, an interface unit 63, and a CPU 64.

  The satellite radio tuner unit 61 demodulates the reception signal received by the antenna element 21 and outputs an audio signal. This audio signal is converted into a digital audio signal by the digital demodulator 62 and supplied to the interface unit 63. The interface unit 63 converts the digital audio signal into an output signal for sending to the head unit 30 that is an external device. The interface unit 63 functions as an audio / serial conversion unit that converts a digital audio signal into a serial signal. The serial signal is sent to the head unit 30 via the serial bus cable 40. The CPU 64 controls the digital demodulator 62 and the interface unit 63.

  On the other hand, the head unit 30 includes an interface unit 31 that receives a serial signal transmitted from the antenna device 20 via the serial bus cable 40. The interface unit 31 functions as a serial / audio conversion unit that converts the received serial signal into an audio signal.

  In this manner, in the receiving system 10, the audio signal is converted into a serial signal on the antenna device 20 side, and the serial signal is converted again into an audio signal on the head unit 30 side.

  According to such a configuration, the user can purchase the satellite radio compatible head unit 30 at low cost. Then, after deciding to view the satellite radio broadcast, the user can easily view the satellite radio broadcast by purchasing the antenna device 20. In addition, since data is exchanged between the antenna device 20 and the head unit 30 via the serial bus cable 40, there is no need to consider the loss of gain of the conventional RF coaxial cable 40A. Therefore, the length of the serial bus cable 40 can be increased.

  Next, the configuration of the antenna device 20 according to an embodiment of the present invention will be described with reference to FIGS. The illustrated antenna device 20 is a planar antenna. The antenna device 20 includes a planar antenna element 21 made of a rectangular metal plate. The planar antenna element 21 has a receiving surface for receiving satellite waves or terrestrial waves. A circuit board 23 is disposed in parallel to the planar antenna element 21 and at a predetermined interval. A ground pattern (described later) is formed on the upper surface of the circuit board 23. A feeding conductor 24 is disposed between the planar antenna element 21 and the circuit board 23.

  Referring to FIG. 9, various electronic components including the above-described satellite radio tuner unit 61, digital demodulation unit 62, interface unit 63, and CPU 64 are arranged on the back surface (bottom surface, one surface) 23 b of the circuit board 23. Has been. The digital demodulator 62 is composed of a baseband IC. The interface unit 63 is composed of an interface chip. The satellite radio tuner unit 61 includes a low noise amplifier (LNA) 22 and a tuner IC 611.

  As shown in FIG. 5, these various electronic components are covered with a metal cover 25 for electromagnetic shielding. Each component described above is housed in a case formed by the upper case 26 and the lower case 27. Reference numeral 28 denotes packing, and reference numeral 29 denotes a cable and a bushing.

  As shown in FIG. 8, the upper case 26 and the antenna element 21 are positioned by the four protrusions 261 that protrude integrally with the upper case 26. The antenna element 21 is fixed to the upper case 26 by welding the tip of the protrusion 261.

  The circuit board 23 is screwed to four protrusions 262 that are integrally provided on the upper case 26 so that the distance in the height direction from the antenna element 21 is positioned.

  The packing 28 is provided with a groove 281 in an annular shape. The upper case 26 is provided with a wall portion 263 that is integrally formed and protrudes annularly around the antenna unit. The packing 28 is attached by inserting the wall portion 263 of the upper case 26 into the groove 281, and is crushed between the wall portion 271 formed integrally with the inner wall of the lower case 27 to form a waterproof structure.

  Eight columnar members 264 are integrally provided around the wall portion 263 of the upper case 26. The lower case 27 is also provided with columnar members 272 at positions corresponding to these columnar members 264. The upper case 26 and the lower case 27 are fixed by screwing both the columnar members 264 and 272.

  The wall portion 271 of the lower case 27 is formed with a U-shaped notch 271a into which the cable and the bushing of the bushing 29 are press-fitted. The bushing of the cable and bushing 29 has a U-shaped groove 291 into which the notch 271a portion of the lower case 27 is inserted. And the packing 28 is crushed by the upper surface of this bushing, and it is set as the waterproof structure.

  FIG. 10 shows a circuit board 23 used in the antenna device 20 of the present embodiment. The illustrated circuit board 23 is a circuit board on which IVH (Interstitial Via Hole) is formed. As shown in FIG. 10, the IVH is composed of a blind via 23c and a buried via 23d. Therefore, the upper surface (the other surface) 23a of the circuit board 23 has no conduction hole.

  As a result, as shown in FIG. 11, an antenna radiation ground pattern 231 can be formed on the entire upper surface (the other surface) 23a of the circuit board 23.

  On the other hand, in a circuit board 23A in which a Thru hole is formed as shown in FIG. 12, a conduction hole is formed in the upper surface 23Aa. Therefore, a ground pattern cannot be formed on the upper surface 23Aa of the circuit board 23A. As a result, in the circuit board 23A in which the Thru Hole is formed, it is necessary to provide the antenna radiation ground plate 72 via the insulating sheet 71 on the upper surface 23Aa, as shown in FIG.

  In other words, by using the circuit board 23 on which IVH is formed as the circuit board, equivalent characteristics can be obtained without using the antenna radiation ground plate 72 and the insulating sheet 71. In this manner, by forming the ground pattern 231 on the entire upper surface 23a of the circuit board 23, the insulating sheet 71 and the antenna radiation ground plate 72, which are conventionally required, become unnecessary, and the cost and size of the antenna device 20 can be reduced. Can be achieved.

  Although the present invention has been described above with reference to preferred embodiments, it is needless to say that the present invention is not limited to the above-described embodiments. The antenna device according to the present invention can be used in a wide range of fields such as in-vehicle appliances, household appliances, portable devices, game machines, personal computers, and the like. In addition, by using a display controller, satellite radio broadcasts can be viewed even on devices that do not support satellite radio.

It is a block diagram which shows a 1st conventional receiving system. It is a block diagram which shows the 2nd conventional receiving system. It is a block diagram which shows the receiving system with which the antenna apparatus which concerns on one embodiment of this invention is applied. It is a block diagram which shows the structure of the antenna apparatus used for the receiving system shown by FIG. It is a disassembled perspective view of the antenna apparatus which concerns on one embodiment of this invention used for the receiving system shown by FIG. FIG. 6 is an assembled perspective view showing the antenna device shown in FIG. 5 with the upper case removed. FIG. 6 is an assembled perspective view showing the antenna device shown in FIG. 5 with a lower case removed. It is sectional drawing of the antenna apparatus shown by FIG. It is a top view which shows the various electronic components mounted in the bottom face (back surface) of the circuit board used for the antenna apparatus shown by FIG. It is sectional drawing of the circuit board shown in FIG. It is sectional drawing which shows the circuit board shown in FIG. 10, and the ground pattern formed in the upper surface (the other surface). It is sectional drawing of the circuit board used for the conventional antenna device. It is sectional drawing which shows the circuit board shown in FIG. 12, and the insulating sheet and antenna radiation ground board which are provided in the upper surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reception system 20 Antenna apparatus 21 Antenna element 22 Low noise amplifier (LNA)
23 Circuit board 23a Upper surface (the other surface)
23b Back side (one side)
231 Ground pattern 24 Power supply conductor 25 Metal cover 26 Upper case 27 Lower case 30 Head unit (external device)
31 Interface Unit 40 Serial Bus Cable 60 Satellite Radio Tuner 61 Tuner Unit 62 Digital Demodulation Unit 63 Interface Unit 64 CPU

Claims (4)

  In an antenna device comprising an antenna element having a receiving surface for receiving satellite waves or terrestrial waves, a circuit board, and an electronic component mounted on one surface of the circuit board, a ground is provided on the other surface of the circuit board. An antenna device, wherein a pattern is formed, and the receiving surface of the antenna element and the ground pattern are disposed to face each other with a predetermined interval.   The antenna device according to claim 1, further comprising a metal cover that electromagnetically shields the electronic component.   The antenna device according to claim 1, further comprising a feeding conductor disposed between the antenna element and the ground pattern. 4. The electronic component according to claim 1, further comprising: a tuner unit that demodulates radio waves received by the antenna element and outputs an audio signal; and an interface unit that converts the audio signal into a serial signal. The antenna device described in 1.

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