JP2010074489A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna device capable of attaining successful characteristics in all the frequency bands by suppressing characteristic deterioration in an existing radiation element even when a new radiation element is added. <P>SOLUTION: The antenna device is constituted so that a first plate-like radiation element 6 and a second plate-like radiation element 7 are held on the top surface of an element holding part 8, a power supply part 4 and a short-circuiting part 5 are extended from the vicinity of ends to which the radiation elements 6, 7 are connected to a lower part of the side to constitute an inverse F antenna 9, the power supply part 4 of the inverse F antenna 9 is connected to a wireless circuit 20, the short-circuiting part 5 is connected to a land 3, attached to the top surface of a substrate 1, and a chip inductor 11 is connected between the land 3 and a ground plate 2, and a third new radiation element 10, one end 10A of which is connected to the land 3 is provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an antenna device used in a portable wireless device such as a cellular phone.

  In recent years, portable wireless devices typified by mobile phones have used a plurality of wireless systems with different frequency bands in order to expand the service area, and antenna devices used for the wireless devices can also support a plurality of frequency bands. It is illustrated. In addition, there is a growing demand for mobile devices such as GPS, Bluetooth, WiFi, and other multi-band antenna devices that support frequencies of wireless systems other than mobile phones. Also, built-in antennas are often used with emphasis on the convenience and design of mobile phones, and inverted F antennas having an impedance adjustment function are widely used.

  An antenna device using such a conventional inverted F antenna will be described with reference to FIG.

  FIG. 4 is a perspective view of a conventional antenna apparatus. In FIG. 4, reference numeral 8 denotes a rectangular parallelepiped element holding portion made of synthetic resin, and a belt-like first radiating element 6 made of a conductive metal and a belt-like shape on the upper surface thereof. The second radiating element 7 is provided. The first radiating element 6 and the second radiating element 7 are connected at one end, and the power feeding part 4 and the short-circuit part 5 extend from the vicinity of the connected end part to the lower side of the side surface of the element holding part 8, respectively. The dual-band inverted-F antenna 9 is constituted by these.

  Reference numeral 1 denotes a substrate, on which a ground plate 2, a land 3 and a radio circuit 20 formed by a surface copper foil pattern are provided. The lower end of the power feeding part 4 of the inverted F antenna 9 is connected to the radio circuit 20, and the lower end of the short-circuit part 5 is connected to the land 3 and fixed on the substrate 1 in a mounted state. A chip inductor 11 is connected between the land 3 and the ground plate 2.

  A third radiating element 10 formed of a surface copper foil pattern is provided on the substrate 1, and one end 10 </ b> A is connected to the ground plate 2. The third radiating element 10 faces the first radiating element 6 and the second radiating element 7 through the element holding portion 8 in the vertical direction.

  In the antenna device configured as described above, the first radiating element 6 resonates in a low first frequency band, and the second radiating element 7 resonates in a high second frequency band, for example, 900 MHz band and 1.9 GHz, respectively. Covers the frequency band of mobile phone radio systems. By adjusting the position and thickness of the short-circuit portion 5, the reverse F antenna 9 has a dual-band impedance adjustment by appropriately setting the electrical length from the power feeding portion 4 to the ground plate 2 via the radiating element. The performance of the inverted F antenna 9 is exhibited. In addition, although detailed illustration etc. are abbreviate | omitted, the element holding | maintenance part 8 hold | maintains these 1st radiation elements 6, the 2nd radiation element 7, the short circuit part 5, and the electric power feeding part 4 stably.

  The third radiating element 10 resonates in a third frequency band that is intermediate between the first frequency band and the second frequency band, covers, for example, a 1.5 GHz band GPS frequency band, and has three frequencies as an antenna device. A triple band antenna corresponding to the band is configured.

  Further, the chip inductor 11 changes the position and thickness of the short-circuit portion 5 when the electrical length from the power supply portion 4 to the ground plate 2 is appropriately adjusted every time the specification of the mobile phone wireless system is changed. The main purpose is to easily adjust the electrical length and impedance by replacing the chip inductor 11 having a different inductance value without changing the metal mold or the like forming the member.

  Further, as is well known, since the inductor has an impedance corresponding to the frequency, the adjusted electrical length has frequency characteristics, becomes a low impedance in the low first frequency band, and approaches the ground state electrically. The operation mode of the inverted F antenna is maintained, but the impedance is high in the second high frequency band, and the operation is different from being close to the operation mode of the monopole antenna by approaching the open state electrically away from the ground. There is also a secondary effect that an antenna having a mode can be designed.

  In general, in a portable wireless device such as a mobile phone, a radiating element is formed by a radiating element of an antenna device and a metal part of the device such as a ground plate of a substrate, and electromagnetic field radiation is generated between the two radiating elements. . At this time, it is well known that the farther away the bipolar radiation elements are, the more efficiently the radiation is radiated and the closer the opposite is, the less the radiation is.

  The method of connecting the third radiating element 10 to the ground plate 2 can constitute a triple band antenna that effectively uses a narrow arrangement space, and is particularly effective for adding a GPS frequency band.

As prior art document information related to the invention of this application, for example, Patent Document 1 and Patent Document 2 are known.
JP 2005-109636 A JP 2003-258527 A

  However, in the conventional antenna device, since the third radiating element 10 extends from the ground plate 2 on the substrate 1, the ground plate 2 extends for the first radiating element 6 and the second radiating element 7. As a result, the facing range is increased, the electrical coupling with the ground plate 2 is strengthened, and the characteristics of the first and second frequency bands are deteriorated as compared to before the third radiating element 10 is added. There was a problem to do.

  The present invention solves such a conventional problem, and even if a new radiating element is added, the characteristic deterioration of the frequency band in which the existing radiating element operates is suppressed, and it is good in each frequency band. An object of the present invention is to provide an antenna device capable of realizing characteristics.

  In order to achieve the above object, the present invention has the following configuration.

  According to a first aspect of the present invention, there is provided a substrate having a radio circuit, a ground plate, and a land, a plate-shaped radiating element disposed to face the substrate surface, and a power feeding unit connected to the radiating element. An inverted F antenna having an element holding unit that holds a short circuit unit connected to the radiating element, a feeding unit of the inverted F antenna is connected to a radio circuit of the substrate, and the short circuit unit is connected to the land. In the antenna device in which the ground plate and the land are connected by an inductance element, a new radiating element having one end connected to the land is provided. Since the new radiating element is connected to the ground plate via the inductance element, the length of the new radiating element can be shortened and the frequency band in which the existing radiating element operates can be reduced. of Suppressing sexual degradation, it has the effect that it is possible to realize a good characteristic in the frequency band radiating elements each.

  The invention according to claim 2 is the invention according to claim 1, wherein one end portion of the new radiating element is connected to the short-circuit portion instead of being connected to the land, and is arranged on the side surface of the element holding portion. Since all the radiating elements are held in the element holding portion, the multi-band antenna can be easily handled on the inverted F antenna side without changing the substrate.

  As described above, according to the present invention, the length of a new radiating element provided for adding a new operating frequency to the inverted F antenna can be shortened, and the characteristics in the frequency band in which the existing radiating element operates can be reduced. An advantageous effect is obtained in that an antenna device can be obtained in which deterioration can be suppressed and good characteristics can be realized in each frequency band.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  In addition, the same code | symbol is attached | subjected to the part of the structure same as the structure demonstrated in the term of the prior art, and detailed description is simplified.

(Embodiment 1)
FIG. 1 is a perspective view of an antenna apparatus according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a ground plate 2 formed by a surface copper foil pattern on the upper surface and a distance from the ground plate 2. It is a board | substrate in which the radio | wireless circuit 20 connected with the land 3 similarly formed by the surface copper foil pattern in the position and the said grounding board 2 was provided.

  Reference numeral 8 denotes an element holding portion made of a synthetic resin having a rectangular parallelepiped shape, and on its upper surface, plate-shaped first radiating element 6 and second radiating element 7 which face each other and are connected to one end are connected. While being held, the side surface holds the feeding portion 4 and the short-circuit portion 5 extending downward from the vicinity of the end where the radiating elements 6 and 7 are connected. It is configured. In addition, the electric power feeding part 4 and the short circuit part 5 are arrange | positioned at predetermined intervals.

  The inverted F antenna 9 is attached to the upper surface of the substrate 1 with the lower end of the power feeding unit 4 connected to the radio circuit 20 of the substrate 1 and the lower end of the short circuit unit 5 connected to the land 3. A chip inductor 11 as an inductance element is connected between the land 3 and the ground plate 2. And on the board | substrate 1 of the position which touches the element holding part 8 lower surface of the reverse F antenna 9 on the said board | substrate 1, the 3rd radiation | emission element 10 formed with the same surface copper foil pattern as the said grounding board 2 is provided. Yes. One end portion 10A of the third radiating element 10 is connected to the land 3, and these constitute an antenna device.

  In the above configuration, the chip inductor 11 can adjust the impedance and the like by changing the inductance value of the chip inductor 11 without changing the mold for determining the position and thickness of the short-circuit portion 5 in the inverted F antenna 9. In order to obtain the same effect as that obtained by changing the physical electrical length from the power feeding unit 4 to the ground plate 2, it is arranged. And if it is the said structure which connected the end part 10A of the 3rd radiation element 10 to the land 3, the said chip inductor 11 in order to add the 3rd frequency band which operate | moves newly to the said reverse F antenna 9 This greatly contributes to shortening the length of the third radiating element 10 to be provided.

  The third radiating element 10 is regarded as an extension of the ground plate 2 for the first radiating element 6 and the second radiating element 7, and the facing range with the ground plate 2 is increased. Since the third radiating element 10 is shortened by the above action, the ground plate 2 is moved away from the first radiating element 6 and the second radiating element 7 by the shortened length, and the facing range is reduced, and the first and second frequencies are reduced. This will improve the radiation efficiency of the electromagnetic field in the band.

  Thus, according to the present embodiment, even if a third radiating element 10 is newly added on the substrate 1 at a position facing the first radiating element 6 and the second radiating element 7, Since the one end portion 10A is connected to the land 3 so as to be connected to the ground plate 2 via the chip inductor 11, the length of the third radiating element 10 can be shortened, and the one end portion 10A is provided on the inverted F antenna 9. It is possible to suppress deterioration of characteristics in the frequency band in which the first radiating element 6 and the second radiating element 7 are operated, and to realize good characteristics in the frequency bands of the radiating elements 6, 7, and 10.

(Embodiment 2)
The second embodiment will be described below. In addition, the same code | symbol is attached | subjected to the part of the structure same as the structure of Embodiment 1, and detailed description is abbreviate | omitted.

  FIG. 2 is a perspective view of an antenna device according to the second embodiment of the present invention. As shown in FIG. 2, one end of each antenna device is connected to the upper surface of the element holding portion 8. The first radiating element 6 and the second radiating element 7 are arranged, and the power feeding part 4 and the short circuit are formed along the side surface of the element holding part 8 from the vicinity of the connected end of the first radiating element 6 and the second radiating element 7. The fact that the portion 5 extends downward is the same as that according to the first embodiment, but in the present embodiment, the third radiating element 13 is connected to the land 3. Instead, one end portion 13A is connected to the intermediate position of the short-circuit portion 5, and the third radiating element 13 is provided in an arrangement state extending from the one end portion 13A to the side surface of the element holding portion 8. 7 and 13 are held on the surface of the element holding portion 8 and are inverted F antennas. Is different is that they are configured to 12.

  Then, the lower end of the power feeding unit 4 of the inverted F antenna 12 is connected to the radio circuit 20, and the lower end of the short-circuit unit 5 is connected to the land 3 and attached on the substrate 1, and between the land 3 and the grounding unit 2 The chip inductor 11 is connected to constitute an antenna device.

  In the above configuration, the third radiating element 13 is substantially integrally formed with the first radiating element 6 and the second radiating element 7 and formed from the same member, so that the surface for the third radiating element 13 is formed on the substrate 1. There is no need to form a copper foil pattern or the like. Further, since the short-circuit portion 5 is connected to the land 3 on the substrate 1, the third radiating element 13 connected to the short-circuit portion 5 is connected to the ground plate 2 via the short-circuit portion 5 and the chip inductor 11. Thus, the length of the third radiating element 13 can be shortened.

  Therefore, the deterioration of the characteristics of the first radiating element 6 and the second radiating element 7 due to the addition of the third radiating element 13 is suppressed, and a favorable characteristic is realized in each frequency band of the radiating elements 6, 7, and 13. it can.

  As described above, according to the present embodiment, since all the radiating elements 6, 7, and 13 can be concentrated on the inverted F antenna 12, only three inverted F antennas 12 can be used without changing the substrate 1. A so-called multiband antenna including the elements 6, 7, and 13 can be easily handled.

  In the first and second embodiments, examples of the inverted F antennas 9 and 12 having the first and second radiating elements 6 and 7 as the existing radiating elements in the element holding unit 8 are described. As described above, as shown in the perspective view of FIG. 3, the existing F-radiation element 14 may be an inverted F antenna 15, and in this case, it is provided to newly add an operating frequency. It is similarly effective if the radiating element 10 is configured by connecting one end portion 10A thereof to the land 3 connected to the ground plate 2 via the chip inductor 11.

  Further, even if there are three or more existing radiating elements, it is equally effective if one end of the newly added radiating element is connected to the ground plate via an inductance element.

  The antenna device according to the present invention can shorten the length of a new radiating element provided to add a new operating frequency to the inverted-F antenna, and suppresses characteristic deterioration in the frequency band in which the existing radiating element operates. It has an advantageous effect that good characteristics can be realized in each frequency band, and is useful for portable wireless devices such as mobile phones.

The perspective view of the antenna apparatus by the 1st Embodiment of this invention The perspective view of the antenna device by the 2nd Embodiment of this invention The perspective view of the antenna device by the other form of this invention A perspective view of a conventional antenna device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Grounding board 3 Land 4 Feeding part 5 Short circuit part 6 1st radiation element 7 2nd radiation element 8 Element holding part 9, 12, 15 Inverted F antenna 10, 13 3rd radiation element 10A, 13A One end part 11 Chip inductor 14 Radiation element 20 Radio circuit

Claims (2)

A board having a radio circuit, a ground plate, and a land, a plate-like radiating element disposed opposite to the board surface, a power feeding unit connected to the radiating element, and a short-circuit unit connected to the radiating element are held. The inverted F antenna having the element holding portion, the feeding portion of the inverted F antenna is connected to the radio circuit of the substrate, the short circuit portion is connected to the land, and the gap between the ground plate and the land is An antenna device connected by an inductance element, wherein a new radiating element having one end connected to the land is provided. The antenna device according to claim 1, wherein one end portion of the new radiating element is connected to the short-circuit portion instead of being connected to the land, and is disposed on a side surface of the element holding portion.

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