JP2010035193A - Antenna apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna apparatus which is made to have a low profile and induces a plurality of resonances of high input impedance. <P>SOLUTION: The antenna apparatus includes a short-circuit path having its front end connected to a ground point disposed nearby a feed point, a first chip-open element extended from a back end of the short-circuit path and having its back end made open, a feed side part element extended from nearby the feed point in the extension direction of the first chip-open element so that one side thereof is close to a ground surface, a second chip-open element extended from nearby a back end of the feed side part element in the extension direction of the first chip-open element and having its back end made open, and a short-circuit element connecting one point on one side of the feed side part element opposed to a side nearby the ground surface or one point on the second chip-open element and the front end of the first chip-open element to each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an antenna device.

  In recent years, wireless communication antennas for electronic devices capable of wireless communication, such as notebook personal computers (hereinafter referred to as notebook PCs), are shifting from whip antennas that have been widely adopted so far to built-in antennas. . Since the built-in antenna has an antenna element built in the housing, the built-in antenna has advantages such as easier handling during use and storage than the whip-type antenna, and increased flexibility in housing design.

  However, an electronic device equipped with a built-in antenna has an antenna input impedance due to the fact that the antenna element and a metal part such as a peripheral circuit mounted on the substrate are placed close to each other due to the downsizing of the housing. In some cases, impedance mismatch occurs between the power supply circuit and the power supply circuit, resulting in performance degradation.

  Therefore, a folded monopole antenna is used as a means for preventing a reduction in input impedance of the built-in antenna. The folded monopole antenna is an antenna in which two or more monopole antennas are placed in close proximity in parallel and their tips are connected to each other, and one of these monopoles is connected to a central feeding point.

  According to this folded monopole antenna, the input impedance of the antenna can be increased compared to a normal monopole antenna that does not fold, and the impedance value can be adjusted by the ratio of the wire diameters of the parallel lines. There is. However, since the folded monopole antenna tends to be larger in shape than the monopole antenna alone, it is necessary to devise such as three-dimensional wiring of the antenna elements in order to incorporate it in a small electronic device.

  In view of this, there has been proposed a technique that can generate resonance at a plurality of resonance frequencies by adding another antenna to the conventional inverted-F antenna (see Patent Document 1).

JP 2003-158419 A

  However, the inverted F antenna described in Patent Document 1 has the following problems. FIG. 50 is an explanatory diagram showing an antenna designed with reference to the basic configuration of the inverted-F antenna described in Patent Document 1. In FIG. As shown in FIG. 50, the inverted F antenna described in Patent Document 1 includes a radiation conductor (36 mm) 1 disposed opposite to the ground conductor 2, and a short-circuit means for connecting the radiation conductor 1 and the ground conductor 2. (8 mm) 3, a power supply that extends between the radiation conductor 1 and the ground conductor 2 and is connected to a grounding point where the short-circuit means 3 is connected to the ground conductor 2 and a power supply point 4 that is 1 mm apart. A power supply conductor (80 mm) 6 connected to the power supply line 5 is provided, and power is supplied to the radiation conductor 1 and the power supply conductor 6 through the power supply line 5.

  FIG. 51 is a Smith chart showing a change in input impedance of the inverted F antenna shown in FIG. The Smith chart shown in FIG. 51 is a Smith chart showing changes in the input impedance of the inverted F antenna when the frequency signal supplied from the feeding point 4 is changed in the range of 700 to 2500 MHz. As shown in FIG. 51, the locus of the impedance of the inverted F antenna shown in FIG. 50 is greatly shifted from 50Ω which is the center of the Smith chart.

  In the inverted F antenna shown in FIG. 50, the current flowing from the feeding point 4 to the ground point indicated by the arrow in FIG. 50 is affected, and the inductivity of the input impedance is increased. There is a problem that it cannot be taken.

  The present invention has been made in view of the above, and an object of the present invention is to provide an antenna device that can reduce the height of the antenna device and generate a plurality of resonances with high input impedance.

  In order to solve the above-described problems and achieve the object, an antenna device according to the present invention includes a short-circuit path connected to a ground point whose start end is disposed close to a feeding point, and a termination of the short-circuit path. A first open end element that is extended from the end of the first open end element, and extends in the extending direction of the first open end element from the vicinity of the feeding point so that one side thereof is close to the ground plane. A power feeding side element that is connected to the power feeding side element, and extends in a direction in which the first tip opening element extends from a connection point between the power feeding side element that is a terminal of the power feeding side element, A second tip opening element whose end is open, a point on one side facing a side close to the ground plane of the power feeding side element, or a point on the second tip opening element, and the first tip opening element. A short-circuit element connecting the start end of The length from the point to the end of the first tip opening element through the short-circuit path and the first tip opening element is a length of about one quarter wavelength of the first resonance frequency, and the short circuit from the ground point The length from the path, the short-circuit element, and the end of the front second tip opening element through the second tip opening element is approximately a quarter wavelength of the second resonance frequency.

  The antenna device according to the present invention includes a short-circuit path whose start end is connected to a ground conductor, a first open end element that extends from a terminal end of the short-circuit path and that is open at the end, and the first Provided between the open end element and the grounding conductor, and connected to the feed side element extending in the extending direction of the first open end element from the vicinity of the feed point, and to the feed side element, A second tip opening element extending in a direction in which the first tip opening element extends from a connection point with the feeding side element, which is a terminal end of the power feeding side element, and the terminal opening being open; A short-circuit element that connects a point on one side of the side element facing a side close to the ground conductor and a start end of the first tip opening element, and the power feeding side element from the feeding point An outer edge including one side adjacent to the grounding conductor, the short-circuit element and The length from the first tip opening element to the terminal end of the first tip opening element is approximately a quarter wavelength of the first resonance frequency, and the ground conductor of the feeding side element from the feeding point And the length from the outer edge including one side close to the end of the front second tip opening element through the second tip opening element to a length of approximately a quarter wavelength of the second resonance frequency. .

  According to the present invention, it is possible to reduce the height of the antenna device and generate a plurality of resonances with high input impedance.

FIG. 1 is a perspective view of the notebook PC according to the first embodiment. FIG. 2 is a circuit configuration diagram of the notebook PC according to the first embodiment. FIG. 3 is a diagram illustrating a configuration of the antenna device. FIG. 4 is an explanatory diagram showing the operating principle of the short-circuit path and the first tip opening element. FIG. 5 is an explanatory diagram illustrating the operating principles of the power feeding side element, the short-circuit element, and the first tip opening element. FIG. 6 is an explanatory diagram showing the operating principle of the short-circuit path, the short-circuit element, and the second tip opening element. FIG. 7 is an explanatory diagram showing the operation principle of the power feeding side element and the second tip opening element. FIG. 8 is a diagram showing a specific shape of the analysis model. FIG. 9 is a diagram showing the shape of the ground conductor of the analysis model. FIG. 10 is a Smith chart showing the antenna characteristics of the analysis model shown in FIGS. FIG. 11 is an explanatory diagram of an antenna realized by the analysis model shown in FIGS. 8 and 9. FIG. 12 is an explanatory diagram of an antenna realized by the analysis model shown in FIGS. 8 and 9. FIG. 13 is an explanatory diagram of an antenna realized by the analysis model shown in FIGS. 8 and 9. FIG. 14 is an explanatory diagram of an antenna realized by the analysis model shown in FIGS. 8 and 9. FIG. 15 is a Smith chart showing the antenna characteristics of an analysis model having a power feeding side element and an analysis model not having a power feeding side element. FIG. 16 is an explanatory diagram showing a flow of current in an analysis model having a power feeding side element. FIG. 17 is an explanatory diagram showing the flow of current in an analysis model that does not have a power feeding side element. FIG. 18 is a schematic diagram of an antenna device according to a modification. FIG. 19 is a diagram illustrating a configuration of an analysis model of an antenna device having a short circuit path. FIG. 20 is a schematic diagram of an analysis model of an antenna device that does not have a short-circuit path. FIG. 21 is a Smith chart showing the antenna characteristics of the analysis model shown in FIGS. 19 and 20. FIG. 22 is a diagram illustrating the configuration of the antenna device according to the third embodiment. FIG. 23 is a diagram illustrating a specific shape of the analysis model. FIG. 24 is a Smith chart showing the antenna characteristics of the analysis model shown in FIG. FIG. 25 is a diagram illustrating the configuration of the antenna device according to the fourth embodiment. FIG. 26 is a diagram illustrating a specific shape of the analysis model. FIG. 27 is a diagram illustrating a specific shape of the analysis model. FIG. 28 is a diagram showing a specific shape of the analysis model. FIG. 29 is an explanatory diagram of resonance that occurs in the analysis model shown in FIG. FIG. 30 is an explanatory diagram of resonance occurring in the analysis model shown in FIG. FIG. 31 is a diagram illustrating an analysis result of the VSWR characteristics in the first resonance frequency band in the analysis models illustrated in FIGS. FIG. 32 is a diagram illustrating the configuration of the antenna device according to the fifth embodiment. FIG. 33 is a diagram showing a specific shape of the analysis model. FIG. 34 is a Smith chart showing the antenna characteristics of the analysis model shown in FIG. FIG. 35 is a diagram illustrating the configuration of the antenna device according to the sixth embodiment. FIG. 36 is a schematic diagram of an analysis model of an antenna device further including a parasitic element. FIG. 37 is a diagram illustrating an analysis result of the VSWR characteristics of an analysis model having no feeding element and an analysis model having a parasitic element. FIG. 38 is a Smith chart showing antenna characteristics of an analysis model having no parasitic element and an analysis model having a parasitic element. FIG. 39 is a diagram illustrating a configuration of an antenna device having a convex portion in a short circuit path. FIG. 40 is a diagram illustrating a specific shape of an analysis model of an antenna device having a convex portion on a short circuit path. 41 is a Smith chart showing the antenna characteristics of the analysis model shown in FIG. FIG. 42 is a diagram illustrating a configuration of an antenna device including an impedance matching circuit on a short-circuit path. FIG. 43 is a diagram illustrating a specific shape of an analysis model of an antenna device including a chip inductor on a short-circuit path. FIG. 44 is a Smith chart showing the antenna characteristics of the analysis model shown in FIG. FIG. 45 is a diagram illustrating various modifications of the antenna device according to the first to seventh embodiments. FIG. 46 is a diagram illustrating a specific shape of the antenna device according to the first embodiment. 47 is a diagram showing an analysis result of the VSWR characteristics of the antenna device shown in FIG. FIG. 48 is a diagram illustrating a specific shape of the antenna device according to the second embodiment. 49 is a diagram showing an analysis result of the VSWR characteristics of the antenna device shown in FIG. FIG. 50 is an explanatory diagram showing an antenna designed with reference to the basic configuration of the inverted-F antenna described in Patent Document 1. In FIG. FIG. 51 is a Smith chart showing a change in impedance of the inverted F antenna shown in FIG.

  Exemplary embodiments of an antenna device according to the present invention will be explained below in detail with reference to the accompanying drawings. An example in which the antenna device of the present invention is applied to a notebook PC which is an electronic device with a built-in housing. However, the present invention is not limited to a notebook PC, and the present invention can be applied to various electronic devices such as a mobile phone and a personal digital assistant with a built-in antenna device.

(First embodiment)
First, the schematic configuration of the notebook PC according to the present embodiment will be described with reference to FIG. FIG. 1 is a perspective view of a notebook PC according to the present embodiment.

  As shown in FIG. 1, the notebook PC 100 according to the present embodiment is roughly configured to include a display unit 101 and a main body 102. The display unit 101 is a liquid crystal display having a liquid crystal panel 103, and has an antenna device 104 for wireless communication above the liquid crystal panel 103. The display unit 101 and the main body 102 are configured to be freely opened and closed by a hinge unit 105.

  The main body 102 includes a wireless communication module 106 as a power supply circuit that generates a high-frequency signal corresponding to a transmission signal in order to transmit and receive wireless radio waves. The wireless communication module 106 is connected to the antenna device 104 via the feeder line 107. The feeder line 107 is a coaxial cable having a diameter of about 1 mm.

  Next, the circuit configuration of the notebook PC 100 according to the present embodiment will be described with reference to FIG. FIG. 2 is a circuit configuration diagram of the notebook PC according to the present embodiment. The wireless communication module 106 is connected to the CPU 201 and the memory 202 via the CPU bus 200. The wireless communication module 106 includes an RF (Radio Frequency) unit, a crystal oscillation unit, and a baseband processing unit (not shown).

  Next, a specific configuration of the antenna device 104 will be described with reference to FIG. FIG. 3 is a diagram illustrating a configuration of the antenna device. The antenna device 104 includes a short-circuit path 301, a first tip open element 302, a power feeding side element 303, a second tip open element 304, a short-circuit element 305, and a ground conductor (GND) 306.

  The ground conductor 306 is a rectangular conductor. Further, in the present embodiment, a ground point 307 that is one point on the ground conductor 306 is disposed close to the feeding point 309.

  The short-circuit path 301 has a starting end connected to the ground point 307. In the present embodiment, the short-circuit path 301 has an inverted L shape, extends from the ground point 307 in a direction perpendicular to the ground conductor 306, bends, and then extends in a direction parallel to the ground conductor 306.

  The first open end element 302 is a linear element, extends from the end of the short-circuit path 301, and is open at the end.

  The power feeding side element 303 is a rectangular plate-shaped element, is provided between the first tip opening element 302 and the ground conductor 306, and extends from the feeding point 309 in the extending direction of the first tip opening element 302. Has been. In the present embodiment, the corner of the power feeding side element 303 is connected to the power feeding point 309.

  The second tip opening element 304 is a linear element, extends from the terminal end of the power feeding side element 303 in the extending direction of the first tip opening element 302, and the terminal end is open. In the present embodiment, the second tip opening element 304 is connected to a corner portion on a diagonal line of the corner portion connected to the feeding point 309.

The short-circuit element 305 is a linear element, and connects the vicinity of the connection point 308 that is the end of the power feeding side element 303 and the start end of the first tip opening element 302.
The connection position of the short-circuit element 305 is not limited to the position shown in FIG. Note that if the connection position of the short-circuit element 305 and the power feeding side element 303 is in the vicinity of the connection point 308 that is the terminal end of the power feeding side element 303, the antenna characteristics in this embodiment become better.

  Next, the operation principle of the antenna device 104 will be described with reference to FIGS.

  FIG. 4 is an explanatory diagram showing the operating principle of the short-circuit path and the first tip opening element. The short-circuit path 301 and the first tip open element 302 have a length of approximately a quarter wavelength from the ground point 307 indicated by the arrow to the terminal end of the first tip open element 302 via the short-circuit path 301 and the first tip open element 302. Resonates in parallel with the length of. (This parallel resonance is called the first parallel resonance.)

  FIG. 5 is an explanatory diagram illustrating the operating principles of the power feeding side element, the short-circuit element, and the first tip opening element. The power feeding side element 303, the short circuit element 305, and the first tip opening element 302 are in series resonance in the first resonance frequency band, and the outer edge of the power feeding side element 303 on the ground conductor 306 side from the power feeding point 309 indicated by the arrow, the short circuit element. The length from the end 305 and the first end opening element 302 to the terminal end of the first end opening element 302 is in series resonance with a length of about a quarter wavelength. (In the following description, the first resonance frequency means the frequency of the first series resonance)

  FIG. 6 is an explanatory diagram showing the operating principle of the short-circuit path, the short-circuit element, and the second tip opening element. The length from the ground point 307 indicated by the arrow to the terminal end of the second tip opening element 304 via the short-circuit path 301, the short-circuit element 305, and the second tip opening element 304 performs parallel resonance with a length of approximately a quarter wavelength. (This parallel resonance is called the second parallel resonance.)

  FIG. 7 is an explanatory diagram showing the operation principle of the power feeding side element and the second tip opening element. The length from the feeding point 309 indicated by the arrow to the outer edge of the feeding side element 303 on the ground conductor 306 side and the terminal end of the second tip opening element 304 via the second tip opening element 304 is approximately four minutes of the second resonance frequency. Resonates in series with the length of one wavelength. (In the following description, the second resonance frequency refers to the frequency of the second series resonance)

  Thus, according to the operating principle of the antenna device 104 according to the present embodiment, the first parallel resonance and the first series resonance are resonated in the first resonance frequency band, and the second parallel resonance and the second series resonance are By resonating in the two resonance frequency bands, a current distribution close to the current distribution generated when the folded monopole antenna is resonated can be generated, so that two resonances with high input impedance can be generated. Therefore, a good input impedance can be obtained even if the antenna device 104 is reduced in height.

  Here, an analysis model of the antenna device 104 and an analysis result of the antenna characteristics will be described.

  First, a specific shape of an analysis model to which the antenna device 104 according to the present embodiment is applied will be described with reference to FIGS. 8 and 9. FIG. 8 is a diagram showing a specific shape of the analysis model. The analysis model of FIG. 8 is designed so that the first resonance frequency band is around 1.8 GHz and the second resonance frequency band is around 900 MHz. FIG. 9 is a diagram showing the shape of the ground conductor of the analysis model. The analysis results listed below are all the results of analysis using the method of moments.

  The short-circuit path 301 extends in a direction perpendicular to the ground conductor 306 from the ground point 307 and then bends and then extends in a direction parallel to the ground conductor 306. The first tip opening element 302 is extended from the end of the short circuit path 301. The feeding side element 303 is a plate-like element, and a corner of the plate-like element is connected to the feeding point 309. The second tip opening element 304 is connected to a corner on a diagonal line of the corner connected to the feeding point 309 of the feeding side element 303, and extends in the extending direction of the first tip opening element 302. Is open. The short-circuit element 305 is connected to the vicinity of the connection point 308 and the start end of the first tip opening element 302, and extends in a direction perpendicular to the ground conductor 306.

  In the analysis model shown here, the ground conductor 306 has a length in the extending direction of the short-circuit path 301 of 100 mm and a length in the direction perpendicular to the extending direction of the short-circuit path 301 of 200 mm. did.

  Next, antenna characteristics of the analysis model shown in FIGS. 8 and 9 will be described with reference to FIGS. FIG. 10 is a Smith chart showing the antenna characteristics of the analysis model shown in FIGS. 11 to 14 are explanatory diagrams of an antenna realized by the analysis model shown in FIGS. 8 and 9. Note that the Smith chart shown in FIG. 10 is a Smith chart showing a change in impedance of this analysis model when the frequency signal supplied from the feeding point 309 is changed in the range of 700 to 2500 MHz.

  As shown in FIG. 10, the impedance locus of this analysis model intersects the horizontal axis of the Smith chart at (2) 1720 MHz, indicating the occurrence of the first parallel resonance indicated by the arrow in FIG. Further, the impedance locus of this analysis model (1) crosses the horizontal axis of the Smith chart at 1810 MHz, and indicates the occurrence of the first series resonance indicated by the arrow in FIG.

  Thus, according to this analysis model, since the first parallel resonance and the first series resonance are generated at close frequencies, the input impedance at the first series resonance frequency can be increased.

  Also, the impedance locus of this analysis model intersects the horizontal axis of the Smith chart at (4) 830 MHz, indicating the occurrence of the second parallel resonance indicated by the arrow in FIG. Also, the impedance locus of this analysis model crosses the horizontal axis of the Smith chart at (3) 920 MHz, indicating the occurrence of the second series resonance indicated by the arrow in FIG.

  Thus, according to this analysis model, since the second parallel resonance and the second series resonance are generated at close frequencies, the input impedance at the second series resonance frequency can be increased. Moreover, since the locus of the Smith chart is drawn in the second resonance frequency band through the vicinity of 50Ω, which is the center of the Smith chart, the band of the second resonance frequency can be widened.

  Next, a comparison result between this analysis model having the feeding side element 303 and an analysis model of a conventional antenna device not having the feeding side element 303 will be described with reference to FIGS. Note that the specific shape of the conventional antenna device is different only in that it does not have the power feeding side element 303, and a detailed description thereof will be omitted. FIG. 15 is a Smith chart showing 700 to 2500 MHz input impedance of an analysis model having a power feeding side element and an analysis model not having a power feeding side element.

  As shown in FIG. 15, the locus of the Smith chart of the analytical model that does not have the power feeding side element 303 shown by reference numeral 1600 in FIG. 16 is shifted upward from around 50Ω that is the center of the Smith chart. As shown in FIG. 16, the inductivity of the input impedance is increased due to a current (indicated by reference numeral 1001 in FIG. 16) that flows from the feeding point 309 to the grounding point 307 through the shorting element 305 and the shorting path 301. Because it will end up.

  On the other hand, as shown in FIG. 15, the impedance locus of the analysis model (antenna device 104) having the feeding side element 303 is 50Ω, which is the center of the Smith chart, compared to the model not having the feeding side element 303. It is drawn in the vicinity. As shown in FIG. 17, this is because current flowing from the feeding point 309 to the grounding point 307 through the outer edge of the feeding side element 303 on the side not close to the grounding conductor 306, the shorting element 305 and the shorting path 301 (reference numeral in FIG. 17). 1701) is smaller than the case where the power supply side element 303 is not provided, and the inductivity of the input impedance is suppressed, and as a result, good impedance matching is obtained.

  Therefore, according to the antenna device according to the present embodiment, by including the power feeding side element 303, the inductivity of the input impedance can be made smaller than that of the antenna device not including the power feeding side element 303, and each resonance Good impedance matching can be obtained in the frequency band.

(First modification)
When the antenna device according to the present embodiment is fed via a coaxial cable, the feeding line adversely affects the antenna characteristics of the antenna device by connecting the outer conductor of the feeding line, which is a coaxial cable, and a short circuit path to ground. It is possible to prevent the effect. Since the configuration of the other antenna device is substantially the same as that of the above-described embodiment, only the processing of parts different from the above-described embodiment will be described.

  FIG. 18 is a schematic diagram of an antenna device according to this modification. Here, a method of attaching the feeder line of the antenna device according to this modification will be described with reference to FIG.

  The short-circuit path 301 of the antenna device 2000 according to this modification is connected to the outer conductor 2001 of the feeder line 107 that is a coaxial cable that feeds the feeding point 309. In the present embodiment, the short circuit path 301 is connected to the outer conductor 2001 of the feeder line 107 by soldering. As described above, according to the antenna device 2000 according to the present modification, by connecting the feeding line 107 to the feeding point 309 located in the antenna device 2000, it is unnecessary to solder and ground the outer conductor 2001. It is not necessary to provide a space, and an area necessary for mounting the antenna device 2000 can be reduced by the amount of the space. Further, by connecting the short-circuit path 301 to the outer conductor 2001 of the feed line 107 and pulling it away from the antenna device, the feed line 107 is connected to the antenna of the antenna device 2000 in order to prevent the antenna device and the feed line 107 from approaching. It is possible to prevent adverse effects on the characteristics.

(Second Embodiment)
In the antenna device according to the present embodiment, the feeding point is arranged at an appropriate distance from the ground point. Since the configuration of the other antenna device is substantially the same as that of the first embodiment, only the parts different from the first embodiment will be described.

  The feeding point 309 is arranged in the extending direction of the first tip opening element 302 from the ground point 307 so as to be separated by approximately one-twentieth wavelength or less of the lower frequency of the first resonance frequency and the second resonance frequency. ing. For example, when the second resonance frequency is lower than the first resonance frequency and is 910 MHz, the feeding point 309 is arranged away from the ground point 307 by 16 mm or less, which is a value obtained by dividing the wavelength λ = 330 mm by about 20 times. The

  Here, an analysis model of the antenna device 104 according to the present embodiment and an analysis result of the antenna characteristics will be described.

  First, with reference to FIG. 19 and FIG. 20, three analysis models in which antenna characteristics are analyzed will be described. FIG. 19 is a diagram illustrating a configuration of an analysis model of an antenna device having a short circuit path. The analysis model of FIG. 19 is designed so that the first resonance frequency band is about 1.8 GHz and the second resonance frequency band is about 900 MHz. FIG. 22 is a schematic diagram of an analysis model of an antenna device that does not have a short-circuit path. Note that, except for the distance between the feeding point 309 and the ground point 307, the analysis model of the antenna device according to the first embodiment is almost the same as that of the first embodiment, and thus description thereof is omitted.

  First, the first analysis model shown in FIG. 19 is a model in which the feeding point 309 is arranged a = 1 mm away from the ground point 307 on the ground conductor 306. A second analysis model (indicated by reference numeral 2200) shown in FIG. 20 is a model that does not have the short-circuit path 301. The third analysis model shown in FIG. 19 is a model in which the feeding point 309 is arranged on the ground conductor 306 with a = 16 mm apart from the ground point 307.

  Next, antenna characteristics of the three analysis models described above will be described with reference to FIG. The Smith chart shown in FIG. 23 is a Smith chart showing changes in the input impedance of each analysis model shown in FIGS. 19 and 20 when the frequency signal supplied from the feeding point 309 is changed in the range of 700 to 1200 MHz. is there.

  The impedance locus of the first analysis model (a = 1 mm) intersects the horizontal axis of the Smith chart at 910 MHz, which is the second resonance frequency. The impedance value at this intersection is about 34Ω, which is close to 50Ω, which is the center of the Smith chart. This is because in this analysis model (a = 1 mm), the second parallel resonance shown in FIG. 13 and the second series resonance shown in FIG. 14 occur at close frequencies.

  On the other hand, the impedance locus of the second analysis model intersects the horizontal axis of the Smith chart at 930 MHz. The impedance at this intersection is 18Ω, which is far from 50Ω, which is the center of the Smith chart, as compared with the first analysis model (a = 1 mm). This is because the second parallel resonance shown in FIG. 13 does not occur in this analysis model (shown in FIG. 20), and the current distribution is close to the resonance in the conventional monopole antenna.

  Also, the impedance locus of the third analysis model (a = 16 mm) intersects the horizontal axis of the Smith chart at 930 MHz. The impedance at this intersection is 26Ω, which is far from 50Ω, which is the center of the Smith chart, than the impedance at the second resonance frequency of the first analysis model. This is because the analysis model (a = 16 mm) has a longer path for determining the frequency of the second parallel resonance shown in FIG. 13 than the first analysis model (a = 1 mm). This is because the second series resonance occurs and the second parallel resonance occurs at a frequency away from the second series resonance.

  According to the analysis results described above, the impedance (26Ω) of the third analysis model (a = 16 mm) is equal to the impedance (34Ω) of the first analysis model (a = 1 mm) and the second analysis model ( The horizontal axis of the Smith chart intersects with an impedance approximately in the middle of the impedance (18Ω) of the short circuit path 301). Therefore, in the present embodiment, a = 16 mm is a value obtained by dividing the wavelength λ = 330 mm of the second resonance frequency (910 MHz) by about 20 times with reference to the third analysis model. It is assumed that 309 is arranged at a distance of approximately 20 times or less of the wavelength λ of the second resonance frequency from the ground point 307.

(Third embodiment)
In the antenna device according to the present embodiment, the inductivity of the input impedance is reduced by setting the length of the feeding side element in the extending direction of the first tip opening element to an appropriate length. The configuration of the other antenna device is substantially the same as that of the second embodiment, and therefore only a part different from that of the second embodiment will be described.

  FIG. 22 is a diagram illustrating a configuration of the antenna device according to the present embodiment. In the power feeding side element 303, the length b in the extending direction of the first tip opening element 302 is assumed to be approximately 1/50 wavelength or more of the second resonance frequency. For example, when the second resonance frequency is 865 MHz, the power supply side element 303 has a length b from the power supply point 309 in the extending direction of the first tip opening element 302 (parallel to the ground conductor 306) having a wavelength λ. = 7 mm or more with 346 mm reduced to about 1/50.

  Here, an analysis model in which b is changed in the antenna device 104 according to the present embodiment and an analysis result of the antenna characteristics will be described.

  First, with reference to FIG. 23, three analysis models that have been analyzed for antenna characteristics will be described. FIG. 23 is a diagram illustrating a specific shape of the analysis model. The analysis model of FIG. 23 is designed so that the first resonance frequency band is about 1.8 GHz and the second resonance frequency band is about 900 MHz. Except for the shape of the power feeding side element 303, the analysis model of the antenna device according to the second embodiment is almost the same as that of the analysis model, and the description thereof is omitted.

  First, the first analysis model is a model in which b of the power feeding side element 303 is 5 mm. The second analysis model is a model in which b of the power feeding side element 303 is 6 mm. The third analysis model is a model in which b of the power feeding side element 303 is 7 mm.

  Next, antenna characteristics of the three analysis models described above will be described with reference to FIG. The Smith chart shown in FIG. 26 is a Smith chart showing the change in input impedance of each analysis model shown in FIG. 25 when the frequency signal supplied from the feeding point 309 is changed in the range of 700 to 1200 MHz. .

  The loci of the impedance of the first analysis model (b = 5 mm) and the second analysis model (b = 6 mm) do not cross the horizontal axis of the Smith chart, and are shifted to the top of the Smith chart. ing. This is because the length of the feeding side element 303 in the extending direction of the first open end element is not sufficient, so that the feeding point 309 is changed to the grounding point 307 as in the case of the conventional antenna device configured with linear elements. This is because the influence of the flowing current cannot be suppressed and the inductivity of the input impedance is high. On the other hand, the impedance locus of the third analysis model (b = 7 mm) intersects the horizontal axis of the Smith chart at 840 MHz and 860 MHz, and the second parallel resonance shown in FIG. 13 and the second series resonance shown in FIG. Can be confirmed.

  According to the analysis result described above, it can be seen that the inductivity of the input impedance decreases as b of the power feeding side element 303 increases. Therefore, in the present embodiment, b = 7 mm is a value obtained by subtracting the wavelength λ = 365 mm of the second resonance frequency (865 MHz) by about 50 times with reference to the third analysis model. The length b of the first tip opening element 302 in the extending direction (parallel to the ground conductor 306) is approximately 1/50 or more of the second resonance frequency.

(Fourth embodiment)
The antenna device according to the present embodiment prevents the input impedance from becoming too high by connecting the connection point, which is the terminal end of the power feeding side element, and the start end of the first tip open element with a short-circuit element. As a result, the first resonance frequency band is widened. The configuration of the other antenna apparatus is substantially the same as that of the third embodiment, and only the parts different from the third embodiment will be described.

  FIG. 25 is a diagram illustrating a configuration of the antenna device according to the present embodiment. The short-circuit element 305 connects the connection point 308 that is the terminal end of the power feeding side element 303 and the start end of the first tip opening element 302.

  Here, an analysis model in which the position to which the short-circuit element 305 is connected in the antenna device 104 according to the present embodiment and an analysis result of the antenna characteristics will be described.

  First, with reference to FIGS. 26 to 28, three analysis models in which antenna characteristics are analyzed will be described. 26 to 28 are diagrams illustrating specific shapes of the analysis model. 26 to 28 are designed so that the first resonance frequency band is about 1.8 GHz and the second resonance frequency band is about 900 MHz. The analysis models other than the connection position of the short-circuit element 305 are the third models. Since it is almost the same as the analysis model of the antenna device according to the embodiment, the description is omitted.

  The analysis model shown in FIG. 26 offsets the connection position of the short-circuit element 305 from the connection point 308 to the short-circuit path 301 side by shortening the length of the short-circuit path 301 in the extending direction of the first tip opening element 302. Model. In the analysis model shown in FIG. 27, by increasing the length of the short-circuit path 301 in the extending direction of the first tip opening element 302, the connection position of the short-circuit element 305 is changed from the connection point 308 to the first tip opening element 302. This model is offset in the extending direction. The analysis model shown in FIG. 28 is a model in which the short-circuit element 305 is connected to the connection point 308.

  Next, the analysis results of the antenna characteristics of the analysis models shown in FIGS. 26 to 28 will be described with reference to FIGS. FIG. 29 is an explanatory diagram of resonance that occurs in the analysis model shown in FIG. FIG. 30 is an explanatory diagram of resonance occurring in the analysis model shown in FIG. FIG. 33 is an explanatory diagram of resonance occurring in the analysis model shown in FIG. FIG. 31 is a diagram illustrating an analysis result of the VSWR characteristics in the first resonance frequency band in the analysis models illustrated in FIGS.

  The input impedance characteristics in the first resonance frequency band in the analysis model shown in FIG. 26 will be described with reference to FIG. If the connection position of the short-circuit element 305 is offset from the connection point 308 to the short-circuit path 301 side, the frequency of the first parallel resonance and the frequency of the first series resonance shown in FIG. 29 become too close. The input impedance of the two resonance frequency bands becomes too high, and the cover band becomes narrow.

  The input impedance characteristics in the first resonance frequency band in the analysis model shown in FIG. 27 will be described using FIG. When the connection position of the short-circuit element 305 is offset from the connection point 308 in the extending direction of the tip opening element 302, the frequency of the third parallel resonance and the frequency of the first series resonance shown in FIG. As a result, the input impedance in the second resonance frequency band becomes too high, and the cover band becomes narrow.

  As described above, the first resonance frequency band is affected by the first resonance and the third resonance depending on the position of the short-circuit element 305. However, by setting the connection position of the short-circuit element 305 near the connection point 308, the first resonance frequency band is The balance of the parallel resonance, the first series resonance, and the third parallel resonance is the best, and the first resonance frequency band can be widened.

  Looking at the VSWR characteristic of FIG. 31, the analysis result of the model of FIG. 28 shows that the value of VSWR is smaller than the analysis results of FIG. 26 and FIG. 27, and the first resonance frequency band is wide. I understand. From this, it can be seen that the first resonance frequency band is widened by setting the connection position of the short-circuit element 305 near the connection point 308.

(Fifth embodiment)
The antenna device according to the present embodiment can adjust the inductivity of the input impedance by changing the distance between one side adjacent to the ground plane of the power feeding side element and the ground conductor. Since the configuration of the other antenna device is almost the same as that of the fourth embodiment, only the parts different from the fourth embodiment will be described.

  FIG. 32 is a diagram illustrating a configuration of the antenna device according to the present embodiment. The power feeding side element 303 is provided between the first open end element 302 and the ground conductor 306, and is separated from the ground conductor 306 by approximately 1/100 wavelength c or less of the second resonance frequency. Yes. For example, when the second resonance frequency is 860 MHz, the power feeding side element 303 is separated from the wavelength λ = 348 mm by about 1/100 mm, and is extended substantially in parallel with the ground conductor 306. Yes.

  Here, an analysis model in which c is changed in the antenna device 104 according to the present embodiment and an analysis result of the antenna characteristics will be described.

  First, with reference to FIG. 33, three analysis models that have been analyzed for antenna characteristics will be described. FIG. 33 is a diagram showing a specific shape of the analysis model. 33 is designed so that the first resonance frequency band is about 1.8 GHz and the second resonance frequency band is about 900 MHz, and the analysis model between FIG. Except for the distance, the analysis model of the antenna device according to the fourth embodiment is almost the same as that of the fourth embodiment, and the description thereof is omitted.

  First, the first analysis model is a model in which c is 1 mm. The second analysis model is a model in which c is 2 mm. The third analysis model is a model in which c is 3 mm.

  Next, antenna characteristics of the three analysis models described above will be described with reference to FIG. The Smith chart shown in FIG. 34 is a Smith chart showing a change in impedance of each analysis model shown in FIG. 33 when the frequency signal supplied from the feed point 309 is changed in the range of 700 to 1200 MHz.

  The first analysis model (c = 1 mm) intersects the horizontal axis of the Smith chart at (1) 860 MHz and (2) 840 Mhz, and the occurrence of second parallel resonance and second series resonance can be confirmed. Also in the second analysis model (c = 2 mm), the horizontal axis of the Smith chart intersects with (3) 855 MHz and (4) 835 MHz, indicating the occurrence of the second parallel resonance and the second series resonance. Yes. However, the third analysis model (c = 3 mm) does not intersect the horizontal axis of the Smith chart, and the occurrence of the second parallel resonance and the second series resonance cannot be confirmed.

  According to this analysis model, the inductivity of the input impedance of the antenna device can be reduced by reducing the distance between the feeding side element 303 and the ground conductor 306 (capacitance can be increased). Good impedance characteristics can be obtained in the first and second resonance frequency bands. Therefore, in the present embodiment, with reference to the third analysis model, c = 3 mm is a value obtained by subtracting the wavelength λ = 348 of the second resonance frequency (860 MHz) approximately 100 times. The partial element 303 is provided to be separated from the ground conductor 306 by approximately 1/100 wavelength or less of the second resonance frequency.

(Sixth embodiment)
The antenna device according to the present embodiment further multi-resonates the antenna device by adding a parasitic element so as to be close to the feeding side element of the antenna device according to the above-described embodiment. Since the configuration of the other antenna device is substantially the same as that of the fifth embodiment, only portions different from the fifth embodiment will be described.

  FIG. 35 is a diagram illustrating a configuration of the antenna device according to the present embodiment. As shown in FIG. 35, the antenna device 3800 according to the present embodiment further includes an inverted L-shaped parasitic element 3801 between the second open end element 304 and the ground conductor 306.

  Here, an analysis model of antenna apparatus 3800 according to the present embodiment and an analysis result of the antenna characteristics will be described.

  First, an analysis model obtained by analyzing antenna characteristics will be described with reference to FIG. FIG. 36 is a schematic diagram of an analysis model of an antenna device further including a parasitic element. The analysis model of FIG. 36 is designed so that the first resonance frequency band is about 1.8 GHz and the second resonance frequency band is about 900 MHz. The configuration other than the parasitic element 3801 is the same as that of the fifth embodiment. Since it is almost the same as the analysis model of the antenna device according to the embodiment, the description is omitted.

  The parasitic element 3801 extends in a direction perpendicular to the ground conductor 306 from a position close to the power supply side element 303 and then bends, and then extends in parallel to the ground conductor 306 in the extending direction of the second tip opening element 304. This is an inverted L monopole antenna that extends and opens.

  Next, the antenna characteristics of the analysis model having no parasitic element and the analysis model having the parasitic element shown in FIG. 36 will be described with reference to FIGS. 37 and 38. FIG. 37 is a diagram illustrating an analysis result of an VSWR characteristic of an analysis model having no parasitic element and an analysis model having a parasitic element. The Smith chart shown in FIG. 38 is a Smith chart showing a change in impedance of each analysis model shown in FIG. 37 when the frequency signal supplied from the feeding point 309 is changed in the range of 700 to 2500 MHz.

  First, the analysis results of the VSWR characteristics of the analysis model having no parasitic element and the analysis model 3800 having the parasitic element 3801 shown in FIG. 36 will be described with reference to FIG. As shown in FIG. 37, an analysis model having no parasitic element and an analysis model 3800 having a parasitic element 3801 are both at the second resonance frequency (about 0.9 GHz) and the first resonance frequency (about 1.8 GHz). The VSWR value is small, indicating that good input impedance characteristics are obtained at each resonance frequency. Further, the analysis model 3800 having the parasitic element 3801 becomes smaller at the new resonance frequency (about 2.2 GHz), and shows that the resonance frequency has increased by adding the parasitic element 3801.

  As shown in FIG. 38, the Smith chart trajectory of the analytical model having no parasitic element has two series resonance points, whereas the Smith chart trajectory of the analytical model 3800 having the parasitic element 3801 has a series resonance point. This also indicates that the resonance frequency is increased by adding the parasitic element 3801.

  Thus, according to the antenna device according to the present embodiment, the resonance frequency can be increased by adding a parasitic element in the vicinity of the feeding side element of the antenna device according to the above-described embodiment. As a result, the antenna device can be further resonated.

(Seventh embodiment)
The antenna device according to the present embodiment adjusts the resonance frequency and adjusts the input impedance at the resonance frequency by providing a projecting portion or an impedance matching circuit on the short-circuit path. Since the configuration of the other antenna device is substantially the same as that of the fifth embodiment, only portions different from the fifth embodiment will be described.

  First, an antenna device in which a convex portion is provided on the short circuit path will be described with reference to FIG. FIG. 39 is a diagram illustrating a configuration of an antenna device having a convex portion in a short circuit path.

  The short-circuit path 4201 of the antenna device 4200 according to the present embodiment is bent at at least three points and includes a convex portion 4201a at a part of the path. In the present embodiment, the short-circuit path 4201 is formed with a convex portion 4201 a that is bent at three points in a part of the path that extends in the vertical direction from the ground point 307 to the ground conductor 306.

  Next, with reference to FIG. 40 and FIG. 41, an analysis model of the antenna device 4200 according to the present embodiment and an analysis result of the antenna characteristics will be described. FIG. 40 is a diagram illustrating a specific shape of an analysis model of an antenna device having a convex portion on a short circuit path. The analysis model of FIG. 40 is designed so that the first resonance frequency band is around 1.8 GHz and the second resonance frequency band is around 900 MHz. 41 is a Smith chart showing the input impedance at 700 to 2500 MHz of the analysis model shown in FIG.

  First, an analysis model in which antenna characteristics are analyzed will be described with reference to FIG. Since the configuration other than the short-circuit path 4201 is substantially the same as the analysis model of the antenna device according to the sixth embodiment, description thereof is omitted. The short-circuit path 4201 of the analysis model shown in FIG. 40 extends from the ground point 307 in the direction perpendicular to the ground conductor 306 and then bends in the direction opposite to the extending direction of the first tip opening element 302. The short-circuit path 4201 extends in a direction opposite to the extending direction of the first tip opening element 302 and bends, and then extends in a direction perpendicular to the ground conductor 306. The short-circuit path 4201 extends in the direction perpendicular to the ground conductor 306 and is bent to form a convex portion.

  Next, antenna characteristics of the analysis model shown in FIG. 40 will be described with reference to FIG. As shown in FIG. 41, the Smith chart trajectory of the analytical model in which the convex portion is formed is closer to 50Ω, which is the center of the Smith chart, than the Smith chart trajectory of the analytical model in which the convex portion is not formed. I understand that. Moreover, as shown in FIG. 41, the locus of the impedance of the analysis model without a convex portion does not intersect the horizontal axis of the Smith chart due to the first parallel resonance shown in FIG. 11 and the first series resonance shown in FIG. On the other hand, the locus of the impedance of the analysis model with a convex portion intersects the horizontal axis of the Smith chart by the first parallel resonance shown in FIG. 11 and the first series resonance shown in FIG.

  This is because it is possible to adjust the path length of the short circuit path 301 by forming a convex portion on a part of the path of the short circuit path 301. By changing the path length of the short-circuit path 301, it is possible to adjust the frequencies of the first parallel resonance and the second parallel resonance, thereby adjusting the input impedance characteristics of the first resonance frequency band and the second resonance frequency band. It becomes possible.

  Next, an antenna apparatus in which an impedance matching circuit is provided on the short-circuit path will be described with reference to FIG. FIG. 42 is a diagram illustrating a configuration of an antenna device including an impedance matching circuit on a short-circuit path.

  The short-circuit path 4501 of the antenna device 4500 according to the present embodiment includes an impedance matching circuit 4501a on the path. In the present embodiment, the short-circuit path 4501 includes an impedance matching circuit 4501a such as a chip inductor on the path. Then, by adjusting the value of the chip inductor, the first and second resonance frequencies are adjusted and the input impedance at the resonance frequency is adjusted.

  Next, with reference to FIG. 43 and FIG. 44, an analysis model of the antenna device 4500 according to the present embodiment and an analysis result of the antenna characteristics will be described. FIG. 43 is a diagram illustrating a specific shape of an analysis model of an antenna device including a circuit for impedance matching on a short-circuit path. The analysis model of FIG. 43 is designed so that the first resonance frequency band is around 1.8 GHz and the second resonance frequency band is around 900 MHz. FIG. 44 is a Smith chart showing the input impedance characteristics of the analysis model shown in FIG. 43 at 700 to 2500 MHz.

  First, an analysis model obtained by analyzing antenna characteristics will be described with reference to FIG. Since the configuration other than the short-circuit path 4501 is substantially the same as the analysis model of the antenna device according to the sixth embodiment, the description thereof is omitted. The analysis model shown in FIG. 46 includes a chip inductor (L = 5 nH) 4501a on a path extending from the ground point 307 in a direction perpendicular to the ground conductor 306.

  Next, the antenna characteristics of the analysis model shown in FIG. 43 will be described with reference to FIG. As shown in FIG. 44, the Smith chart trajectory of the analysis model having the chip inductor 4501a on the path is the center of the Smith chart rather than the Smith chart trajectory of the analysis model having no circumferential constant on the path. It can be confirmed that it is close to 50Ω. As shown in FIG. 44, the Smith chart trajectory of the analysis model without the chip inductor does not intersect the horizontal axis of the Smith chart due to the first parallel resonance shown in FIG. 11 and the first series resonance shown in FIG. On the other hand, the locus of the Smith chart of the analysis model with the chip inductor intersects the horizontal axis of the Smith chart by the first parallel resonance shown in FIG. 11 and the first series resonance shown in FIG.

  This indicates that by providing a chip inductor on the short-circuit path 301 and adjusting its value, a convex portion is formed in the short-circuit path, and the same effect as when the length is adjusted can be obtained. . Therefore, it can be seen that by providing a circuit for impedance matching on the short-circuit path 301 and adjusting the value thereof, the first and second resonance frequencies can be adjusted and the input impedance at the resonance frequency can be adjusted.

(Second modification)
Here, various modified examples of the above-described embodiment will be described with reference to FIG. FIG. 45 is a diagram illustrating various modifications of the antenna device according to the first to seventh embodiments. Note that since the configuration of the antenna device is substantially the same as that of the above-described embodiment, only different portions will be described.

  FIG. 45A is an example in which the length of the first tip opening element 4800 in the extending direction is longer than the length of the second tip opening element 304 in the extending direction. FIG. 45B shows an example in which an antenna element 4801 that needs to be fed is further added. FIG. 45C shows an example in which the start end of the second tip opening element 4802 is connected not to one corner of the power feeding side element 303 but to one side on the terminal end side. FIG. 45D shows an example in which the power feeding side element 4803 has a distorted shape. FIG. 45E shows an example in which a plate-like element is used for the short-circuit element 4804. FIG. 45F shows an example in which a linear element is used for the power feeding side element 4805. FIG. 45G shows an example in which the shape of the power feeding side element 4806 is trapezoidal. FIG. 45 (h) shows an example in which the shape of the first tip opening element 4808 or the second tip opening element 4807 is bent. FIG. 45 (i) shows an example in which the shape of the first tip opening element 4809 or the second tip opening element 4810 is a meander shape. FIG. 45J shows an example in which the length of the short-circuit path 4811 is made longer than the short-circuit path 4201 shown in the seventh embodiment and bent. FIG. 45 (k) is an example in which the antenna device according to the first to seventh embodiments is attached by being bent in accordance with the housing shape. (L) is an example in which the position of the feeding point 309 is provided not on the starting end of the feeding side element 303 but on one side close to the ground plane of the grounding conductor 306 of the feeding side element 303.

(First embodiment)
Here, specific examples of the antenna device according to the above-described embodiment will be described with reference to FIGS. FIG. 46 is a diagram illustrating a specific shape of the antenna device according to the present embodiment. 47 is a diagram showing an analysis result of the VSWR characteristics of the antenna device shown in FIG.

  First, the configuration of the antenna device 4900 according to the present embodiment will be described with reference to FIG. The antenna device 4900 according to the present example is connected to the short-circuit path 4901 having an L-shaped fold extending from the grounding point 4907 and the terminal end of the short-circuit path 4901 and is bent into a U-shape. An open element 4902, a feed-side element 4903 that is a plate-like element whose start is connected to a feed point 4909, a second tip open element 4904 that is connected to a connection point 4908 that is a terminal end of the feed-side element 4903, and a first tip A short-circuit element 4905 that connects the starting end of the open element 4902 and the second tip open element 4904, and a parasitic element 4910 that is disposed between the second tip open element 4904 and the ground conductor 4906 are configured.

  Next, the analysis result of the VSWR characteristic of the antenna device 4900 according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 47, the antenna device 4900 according to the present embodiment has a first resonance frequency (about 1.8 GHz), a second resonance frequency (0.9 GHz), and a third resonance frequency (about 2.3 GHz). The VSWR value shows a value of 3 or less in the resonance frequency band, and it can be seen that good input impedance characteristics are obtained at each resonance frequency.

  Thus, according to the antenna device 4900 according to the present example, the same effect as that obtained in the above-described embodiment can be obtained. The antenna device 4900 according to the present embodiment is a planar antenna in which an element pattern is formed in a planar shape, and is mounted on a third-generation mobile phone, and has an 800 MHz band (825 to 960 MHz) and 2 GHz. The band (1710 to 2170 MHz) is covered.

(Second embodiment)
Here, a specific example of the antenna device according to the above-described embodiment will be described with reference to FIGS. FIG. 48 is a diagram illustrating a specific shape of the antenna device according to the present embodiment. 49 is a diagram showing an analysis result of the VSWR characteristics of the antenna device shown in FIG.

  First, the configuration of the antenna device 5200 according to the present embodiment will be described with reference to FIG. The antenna device 5200 according to the present embodiment includes a short-circuit path 5201 having a chip inductor (L = 5nH) 5201a on a path extending from the grounding point 5207, and a first tip open connected to the end point of the short-circuit path 5201. An element 5202; a feeding-side element 5203 that is a plate-like element having a starting end connected to a feeding point 5209; a second tip-opening element 5204 connected to the terminal end of the feeding-side element 5203; and a starting end of the first tip-opening element 5202 A short-circuit element 5205 that connects the vicinity of the connection point 5208 and a parasitic element 5210 disposed between the second tip opening element 5202 and the ground conductor 5206 are configured.

  Next, an analysis result of the VSWR characteristic of the antenna device 5200 according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 49, the antenna device 5200 according to the present embodiment has a first resonance frequency (about 1.8 GHz), a second resonance frequency (0.9 GHz), and a third resonance frequency (about 2.3 GHz). The VSWR value shows a value of 3 or less in the resonance frequency band, and it can be seen that good input impedance characteristics are obtained at each resonance frequency.

  Thus, according to the antenna device 5200 according to the present example, the same effect as that obtained in the above-described embodiment can be obtained. The antenna device 5200 according to the present embodiment is a planar antenna in which an element pattern is formed in a planar shape, and is mounted on a third-generation mobile phone. The 800 MHz band (825 to 960 MHz) and the 2 GHz band (1710 to 2170 MHz). ).

100 notebook PC
DESCRIPTION OF SYMBOLS 101 Display part 102 Main body 103 Liquid crystal panel 104,1800,1900,2000,3800,4200,4500,4900,5200 Antenna apparatus 105 Hinge part 106 Wireless communication module 107,1804,1904,2001 Power supply coaxial cable 200 CPU bus 201 CPU
202 Memory 301, 4201, 4501, 4811, 4901, 5201 Short-circuit path 302, 4800, 4808, 4809, 4902, 5202 First tip open element 303, 4803, 4805, 4806, 4903, 5203 Feed side element 304, 4807, 4810, 4904, 5204 Second open end element 305, 4804, 4905, 5205 Short-circuit element 306, 4906, 5206 Ground conductor 307, 4907, 5207 Ground point 308, 4802, 4908, 5208 Connection point 309, 1803, 1903, 4909, 5209 Feed point 1801, 1901 First antenna element 1802, 1902 Second antenna element 3801 Parasitic element 4201a Convex part 4501a Lumped constant 4801 Antenna element 5201a Chip inductor

Claims (8)

A short-circuit path connected to a grounding point whose starting end is arranged close to the feeding point;
A first tip opening element extending from the end of the short-circuit path and having an open end;
A power feeding side element extending in the extending direction of the first tip open element from the vicinity of the power feeding point so that one side thereof is close to the ground plane;
Connected to the power feeding side element, extends from the connection point with the power feeding side element, which is the end of the power feeding side element, and extends in the extending direction of the first tip opening element, and the terminal is open. A second tip opening element;
A short-circuit element connecting a point on one side facing a side adjacent to the ground plane of the power feeding side element or a point on the second tip open element and a start end of the first tip open element; Prepared,
The length from the ground point to the terminal end of the first tip opening element through the short-circuit path and the first tip opening element is a length of approximately a quarter wavelength of the first resonance frequency,
The length from the grounding point to the end of the front second open end element that has passed through the short circuit path, the short circuit element, and the second open end element is approximately a quarter wavelength of the second resonance frequency. An antenna device characterized by that.   The feeding point is disposed away from the ground point in the extending direction of the first tip opening element by approximately one-twentieth wavelength or less of the lower resonance frequency of the first or second resonance frequency. The antenna device according to claim 1, wherein:   The power feeding side element has a length in the extending direction of the first tip opening element that is approximately 1/50 wavelength or more of the lower resonance frequency of the first and second resonance frequencies. The antenna device according to claim 1, wherein the antenna device is characterized.   The antenna device according to any one of claims 1 to 3, wherein the short-circuit element connects the vicinity of the connection point and a start end of the first tip opening element.   The power feeding side element is provided between the first open end element and the ground conductor, and one side close to the ground plane is between the ground conductor and the first or second resonance frequency. 5. The antenna device according to claim 1, wherein the antenna device is provided at a distance of approximately 1/100 wavelength or less of a lower resonance frequency.   6. The antenna device according to claim 1, further comprising a parasitic element in the vicinity of the feeding side element.   The antenna device according to claim 1, wherein the short-circuit path is bent at at least three points and a convex portion is formed on a part of the path. A short-circuit path whose start is connected to the ground conductor;
A first tip opening element extending from the end of the short-circuit path and having an open end;
A power feeding side element provided between the first tip opening element and the ground conductor and extending in the extending direction of the first tip opening element from the vicinity of the feeding point;
Connected to the power feeding side element, extends from the connection point with the power feeding side element, which is the end of the power feeding side element, and extends in the extending direction of the first tip opening element, and the terminal is open. A second tip opening element;
A short-circuit element connecting a point on one side facing a side adjacent to the ground conductor of the power feeding side element, and a start end of the first tip open element;
The length from the feeding point to the outer edge including one side close to the grounding conductor of the feeding side element, the short-circuit element, and the terminal end of the first tip opening element through the first tip opening element is the first resonance frequency. About a quarter wavelength long,
The length from the feeding point to the outer edge including one side close to the ground conductor of the feeding side element and the end of the front second open end element through the second open end element is approximately a quarter of the second resonance frequency. An antenna device having a length of one wavelength.

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