JP2012129890A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device which can widen a band and can improve antenna performance in a desired frequency band and to provide radio communication equipment including the antenna device.SOLUTION: The antenna device related to an embodiment of this invention includes: a bottom board; an antenna element arranged at an end of the bottom board; and a power feeding portion arranged between the bottom board and the antenna element. The bottom board includes a plurality of current paths making antenna current flowing to the antenna element by power feeding from the power feeding portion flow to a plurality of directions and plurality of paths different in lengths. The radio communication equipment including the antenna device is also provided.

Description

  The present invention relates to an antenna device, and more particularly to a small multiband antenna device built in a wireless communication device.

  In recent years, development of a built-in antenna for a wireless communication device has been promoted. Examples of such an antenna include a built-in antenna dedicated to UWB (Ultra Wide Band) suitable for high-speed data communication, a built-in antenna for cellular, and the like. Due to the miniaturization of the wireless communication device, the internal antenna is also required to be miniaturized. However, in the conventional technology, there are cases where satisfactory electrical performance cannot be obtained even if the miniaturization requirement of the antenna device is satisfied.

  Thus, some built-in antennas for wireless communication devices attempt to realize an antenna that operates in a wide band by making the shape of the antenna element and making the circuit of the power feeding unit tunable. For example, there is a technique (for example, refer to Patent Document 1) that attempts to realize a broadband characteristic by devising the shape of a linear or planar antenna element or capacitive coupling with a ground plane. In addition, there is one that attempts to cope with multi-band by switch control mounted on a meander-shaped antenna element (see, for example, Patent Document 2).

JP 2008-295090 A International Publication No. 08/0888463 Pamphlet

  In recent years, wireless communication devices are increasingly required to support diversification of wireless communication methods and international roaming. For example, GSM850 / 900 has a frequency band of 0.824 to 0.960 GHz. It is necessary to correspond to. However, it is difficult for the antenna devices disclosed in Patent Documents 1 and 2 to operate with high performance over a wide band in these wireless communication systems.

  In addition, in order to make the antenna device according to the prior art compatible with a plurality of wireless communication systems in a wide band, it is necessary to separately mount an antenna, and it is not possible to meet the demand for downsizing of the antenna device unless a mounting space can be secured. Have

  An object of the present invention is to provide an antenna device and a wireless communication device capable of covering a desired frequency band in a wide band. And

  An antenna device according to an embodiment of the present invention includes a ground plane, an antenna element disposed at an end portion of the ground plane, and a power feeding section disposed between the ground plane and the antenna element. Has a plurality of current paths for flowing the antenna current flowing in the antenna element by power feeding from the power feeding section through paths having a plurality of directions and a plurality of different lengths. The antenna device according to the embodiment of the present invention can cover a desired frequency band in a wide band.

  In the antenna device according to an embodiment of the present invention, the ground plane may form the plurality of current paths by combining a plurality of patterns having different shapes. According to the antenna device according to an embodiment of the present invention, the current path through which the antenna current flows can be diversified.

  In the antenna device according to an embodiment of the present invention, the ground plane may form the plurality of current paths by separating a part of the plurality of patterns having different shapes from each other by a predetermined distance. According to the antenna device according to an embodiment of the present invention, the current path through which the antenna current flows can be diversified.

  In the antenna device according to an embodiment of the present invention, the ground plane may include a pattern in which the plurality of patterns having different shapes are polygonal. According to the antenna device according to an embodiment of the present invention, the current path through which the antenna current flows can be diversified.

  In the antenna device according to an embodiment of the present invention, the ground plane may include a pattern having a shape in which the plurality of patterns having different shapes include a curve. According to the antenna device according to an embodiment of the present invention, the current path through which the antenna current flows can be diversified.

  In the antenna device according to an embodiment of the present invention, the antenna element may be a folded L-type antenna. According to the antenna device according to an embodiment of the present invention, it is possible to achieve a wide band of antenna characteristics without changing the antenna shape.

  In addition, a wireless communication device according to an embodiment of the present invention includes the antenna device, and the antenna element and the ground plane are disposed on an inner surface of a housing. According to the wireless communication apparatus according to an embodiment of the present invention, a desired frequency band can be covered in a wide band.

  As described above, according to the antenna device and the wireless communication device including the antenna device according to the embodiment of the present invention, it is possible to realize a wide band and an improvement in antenna performance by devising the shape of the ground plane.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows schematic structure of the antenna apparatus which concerns on the 1st Embodiment of this invention, (a) is a figure which shows schematic structure of an antenna apparatus, (b) is the antenna apparatus shown to (a). It is a figure which shows the coaxial cable at the time of electrically feeding using a coaxial cable in an equivalent circuit. It is a figure which shows schematic structure of the antenna device which concerns on the 1st Embodiment of this invention, (a) is a perspective view which shows schematic structure of an antenna device, (b) shows schematic structure of an antenna device. It is a top view. FIG. 3 is a diagram for explaining the characteristics of the antenna device shown in FIG. 2, (a) is a diagram showing the current distribution of the ground plane of the antenna device shown in FIG. 2, and (b) is shown in FIG. 2. 5 is a graph showing the VSWR characteristics of the antenna device. It is a figure which shows schematic structure of the antenna device which concerns on the 2nd Embodiment of this invention, (a) is a perspective view which shows schematic structure of an antenna device, (b) shows schematic structure of an antenna device. It is a top view. FIG. 5 is a diagram for explaining the characteristics of the antenna device shown in FIG. 4, (a) is a diagram showing a current distribution of the ground plane of the antenna device shown in FIG. 4, and (b) is a diagram shown in FIG. 4. 5 is a graph showing the VSWR characteristics of the antenna device. It is a figure which shows schematic structure of the antenna device which concerns on the 3rd Embodiment of this invention, (a) is a perspective view which shows schematic structure of an antenna device, (b) shows schematic structure of an antenna device. It is a top view. FIG. 7 is a diagram for explaining the characteristics of the antenna device shown in FIG. 6, (a) is a diagram showing the current distribution of the ground plane of the antenna device shown in FIG. 6, and (b) is shown in FIG. 6. 5 is a graph showing the VSWR characteristics of the antenna device. It is a figure which shows schematic structure of the antenna device which concerns on the 4th Embodiment of this invention, (a) is a perspective view which shows schematic structure of an antenna device, (b) shows schematic structure of an antenna device. It is a top view. FIG. 9 is a diagram for explaining the characteristics of the antenna device shown in FIG. 8, (a) is a diagram showing the current distribution of the ground plane of the antenna device shown in FIG. 6, and (b) is shown in FIG. 6. 5 is a graph showing the VSWR characteristics of the antenna device. It is a figure which shows schematic structure of the antenna device which concerns on the 5th Embodiment of this invention, (a) is a perspective view which shows schematic structure of an antenna device, (b) shows schematic structure of an antenna device. It is a top view. It is a figure for demonstrating the characteristic of the antenna apparatus shown in FIG. 10, (a) is a figure which shows the electric current distribution of the ground plane of the antenna apparatus shown in FIG. 6, (b) is shown in FIG. 5 is a graph showing the VSWR characteristics of the antenna device. It is a figure which shows schematic structure of the antenna device which concerns on the 6th Embodiment of this invention, (a) is a perspective view which shows schematic structure of an antenna device, (b) shows schematic structure of an antenna device. It is a top view. FIG. 13 is a diagram for explaining characteristics of the antenna device shown in FIG. 12, (a) is a diagram showing a current distribution of the ground plane of the antenna device shown in FIG. 6, and (b) is a diagram shown in FIG. 6. 5 is a graph showing the VSWR characteristics of the antenna device. It is a graph which shows the VSWR characteristic of the antenna apparatus which concerns on this invention, and the conventional antenna apparatus. It is a figure which shows an example of the conventional antenna apparatus, (a) is an external appearance perspective view which shows the conventional antenna apparatus, (b) is the graph which showed the VSWR characteristic of the antenna apparatus shown to (a). is there. It is a figure which shows another example of the conventional antenna apparatus, (a) is an external appearance perspective view which shows the conventional antenna apparatus, (b) showed the VSWR characteristic of the antenna apparatus shown to (a). It is a graph. It is the figure which showed the electric current distribution of the ground plane of the antenna apparatus shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to the following embodiment, In the range which does not deviate from the summary, it can implement in various aspects.

(Background to the present invention)
In designing a built-in antenna for a wireless communication apparatus, it is usually necessary to consider various conditions such as a used frequency band, an antenna volume, an antenna mounting position, and a ground plane (GND-Plane) size. Hereinafter, as the background to the antenna device according to the embodiment of the present invention, assuming the frequency band (0.824 to 0.894 GHz, 0.88 to 0.96 GHz) of the current cellular band GSM850 / 900, the center frequency The configuration and characteristics of a conventional single-band antenna designed to be about 850 MHz will be described with reference to FIGS.

  FIG. 15 is a diagram showing an example of a conventional antenna device, (a) is an external perspective view showing a conventional antenna device 10, and (b) is a VSWR ( It is the graph which showed the (Voltage Standing Wave Ratio) characteristic. FIG. 16 is a diagram showing another example of a conventional antenna device, (a) is an external perspective view showing a conventional antenna device 20, and (b) is an antenna device 20 shown in (a). It is the graph which showed the VSWR characteristic of. FIG. 17 is a diagram showing a current distribution of the ground plane 14 of the conventional antenna device 10 shown in FIG.

  Referring to FIG. 15A, an antenna device 10 that is an example of a conventional antenna device includes an antenna element 11, a dielectric 12, a power feeding unit 13, and a ground plane 14. The antenna device 10 is a simulation model in which the antenna element 11 is designed as an L-type antenna having a 1 / 4λ electrical length. The antenna unit 16 includes an antenna element 11, a dielectric 12, and a power feeding unit 13. The size of the antenna portion 16 is a thin plate shape having a length of 50 mm, a width of 10 mm, and a height of 4 mm, and the volume is 2 cc. The ground plane 14 was a thin film of 50 mm × 100 mm, which is a general size mounted on a cellular mobile terminal. The antenna unit 16 was installed at the end of the main plate 14 in the longitudinal direction. The dielectric 12 is made of ABS (acrylonitrile butadiene styrene) resin, which is often used for a general built-in antenna.

  FIG. 16A shows an antenna device 20 as another conventional example different from the antenna device 10. The antenna device 20 includes an antenna element 21, a dielectric 22, a power feeding unit 23, and a ground plane 24. The antenna element 21 includes a folded L-shaped antenna 21a having a meander shape. The antenna device 20 is a simulation model in which the antenna element 21 is designed as an L-type antenna having a 1 / 4λ electrical length, similarly to the conventional antenna device 10 shown in FIG. The antenna unit 26 includes an antenna element 21, a dielectric 22, and a power feeding unit 23. The size of the antenna portion 26 is a thin plate shape having a length of 50 mm, a width of 10 mm, and a height of 0.35 mm. The ground plane 14 was a thin film of 50 mm × 100 mm, which is a general size mounted on a cellular mobile terminal. The antenna unit 26 was installed at the end of the base plate 24 in the longitudinal direction. The dielectric 22 is made of polyimide.

  The conventional antenna devices 10 and 20 are designed to assume a GSM850 / 900 frequency band (0.824 to 0.894 GHz, 0.88 to 0.96 GHz) and have a center frequency of about 850 MHz. Is. When the VSWR characteristics of the antenna devices 10 and 20 were analyzed by simulation, the graph results shown in FIGS. 15B and 16B were obtained.

  Referring to FIGS. 15 (b) and 16 (b), the conventional antenna devices 10 and 20 do not satisfy the specification of VSWR <3, which is generally desirable as an antenna for a wireless communication device. It can be seen that good performance cannot be obtained. This is because, in order to realize the miniaturization of the antenna devices 10 and 20, the performance deteriorates due to the deterioration of the characteristics of the narrow band phenomenon due to the deterioration of the impedance and the increase of the Q value.

  Based on the simulation results of the conventional antenna devices 10 and 20 as described above, the inventor actively operates an antenna as a current other than the ground plane 14 illustrated in FIG. The antenna device that can improve the performance was considered. This is because the antenna device can be miniaturized if good performance can be obtained by modifying the separately designed ground plane shape without changing the size of the ground plane.

  FIG. 17 shows the result of analyzing the current distribution of the ground plane 14 when the conventional antenna device 10 is operated at the center frequency using electromagnetic field simulation. As shown in FIG. 17, it can be seen that the current of the ground plane 14 in the conventional antenna apparatus 10 takes a unidirectional current path.

  From this simulation result, in the conventional antenna devices 10 and 20, since the ground planes 14 and 24 have a rectangular shape, the current path in the ground planes 14 and 24 is unidirectional, and the path length is also a plurality of lengths. I understand that I cannot take it. Then, this inventor considered the antenna apparatus which can improve a broadband and performance by devising the shape of a ground plane, and came to the antenna apparatus which concerns on embodiment of this invention shown below.

(First embodiment)
Hereinafter, the antenna device 100 according to the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram illustrating a schematic configuration of an antenna device 100 according to a first embodiment of the present invention, where (a) illustrates a schematic configuration of the antenna device 100, and (b) illustrates a configuration of (a). It is a figure which shows the coaxial cable 107b at the time of supplying electric power to the antenna element 101 from the ground plane 105 in the antenna device 100 using the coaxial cable 107b. FIG. 2 is a diagram showing a schematic configuration of the antenna device 100 according to the first embodiment of the present invention, (a) is a perspective view showing a schematic configuration of the antenna device 100, and (b) is an antenna. 2 is a plan view showing a schematic configuration of the apparatus 100. FIG. FIG. 3 is a diagram for explaining the characteristics of the antenna device 100 shown in FIG. 2, (a) is a diagram showing the current distribution of the ground plane 104 of the antenna device 100, and (b) is the antenna device. It is a graph which shows the VSWR characteristic of 100.

  Referring to FIG. 1A, an antenna device 100 according to the first embodiment of the present invention includes an antenna element 101, a power feeding unit 103, and a ground plane 104. The power feeding unit 103 is disposed between the antenna element 101 and the ground plane 104. The ground plane 104 is connected to the electronic circuit board 105 and grounded. The electronic circuit board 105 and the ground plane 104 are connected at a connection point 107a via a connection line 107b. The position of the connection point 107 a can be arbitrarily designed according to various conditions such as the shape and size of the main plate 104.

  As shown in FIG. 1A, the antenna element 101, the power feeding unit 103, and the ground plane 104 are disposed on the inner surface of the housing 102. The casing 102 is a dielectric, and may be a part of a case of a straight type mobile communication terminal, for example. Since the case of a straight type mobile communication terminal has a larger plane portion compared to a foldable type mobile communication terminal, for example, the base plate 104 is provided on the inner surface of the casing 102 which is the case back. By arranging, even if it is a small space formed between the housing 102 and the electronic circuit board 105, the area where the ground plane 104 is disposed can be increased by making the ground plane 104 into a thin film. By arranging the ground plane 104 along the planar portion of the casing 102, the antenna device 100 can be easily downsized.

  FIG. 1B shows an equivalent circuit when the antenna device 100 shown in FIG. 1A is fed with the coaxial cable 107b. As illustrated, the coaxial cable 107 b can be represented as an equivalent circuit including a coil L, a resistor R, and a capacitor C. The capacitor C is a stray capacitance between the connection line 107b.

  The configuration of the antenna device 100 according to the first embodiment of the present invention will be described in detail with reference to FIG.

  As illustrated in FIGS. 2A and 2B, in the antenna device 100, the antenna element 101, the power feeding unit 103, and the ground plane 104 are arranged on the inner surface of the casing 102 that is a part of the case of the mobile communication terminal. Is done. The power feeding unit 103 is disposed between the antenna element 101 and the ground plane 104. The antenna element 101 is disposed at the end of the main plate 104 in the longitudinal direction. The antenna element 101 is an L-type antenna having a 1 / 4λ electrical length.

  The ground plane 104 has a shape that is a combination of a plurality of patterns L1 to L5 having different shapes, as shown in FIG. As shown in FIG. 2B, the outer shape of the ground plane 104 is the same as the ground planes 14 and 24 in the conventional antenna devices 10 and 20, with a vertical length a2 = 100 mm and a horizontal length a3 = 50 mm. It is rectangular and includes notches k1 to k5. As illustrated, the notches k1 to k5 may be formed by combining a plurality of rectangular shapes having different shapes. The notches k1 to k5 are formed at a predetermined distance from each other, thereby forming a plurality of patterns L1 to L5 including a rectangular shape. As illustrated in FIG. 2A, the base plate 104 is formed such that the cutout portions k1 to k4 are in contact with the side portions of the base plate 104, so that a part of the plurality of patterns L1 to L5 is a predetermined distance d1 to d4. Separated by d4.

  As illustrated in FIG. 2B, the width a1 of the antenna element 101 is 10 mm. Therefore, the antenna device 100 according to the first embodiment of the present invention can be formed within the same area (110 mm × 50 mm) as the area where the conventional antenna devices 10 and 20 described above are arranged.

  The antenna element 101 and the ground plane 104 may be formed on the surface of the casing 102 by using a metal material by a MID (Molded Interconnect Device) technique, or by integrally molding a thin sheet metal. Alternatively, the antenna element 101 and the ground plane 104 may be formed using a flexible substrate having an adhesive on one side and attached to the housing 102. The thickness of the antenna element 101 and the ground plane 104 is about several tens to several hundreds of μm. As a material of the casing 102, an ABS (acrylonitrile butadiene styrene) resin may be used.

  With reference to FIG. 3, the characteristics of the antenna device 100 according to the first embodiment of the present invention will be described in detail.

  FIG. 3A shows the result of analyzing the current distribution of the ground plane 104 when the antenna apparatus 100 is operated at the center frequency using electromagnetic field simulation. As illustrated in FIG. 3A, the current path of the ground plane 104 in the antenna device 100 can take a plurality of current paths having different lengths in a plurality of directions.

  As shown in FIG. 3A, the ground plane 104 is configured to have a plurality of notches k1 to k5 (see FIG. 2), so that the gap between the notches k1 to k4 is interposed between the ground planes 104 on both sides. The generated electromagnetic coupling can be adjusted, and according to the notch k5 formed at a position close to the antenna element 101, the distance between the ground plane 104 and the antenna element 101 can be adjusted, and the ground plane 104 and the antenna can be adjusted. The impedance generated between the elements 101 can be adjusted. The ground plane 104 has a current path formed in the ground plane 104 by separating a part of the plurality of patterns L1 to L5 described above by the notches k1 to k4 by a predetermined distance d1 to d4 (see FIG. 2). Can be configured not to form a loop. By including such a configuration, the ground plane 104 diversifies the current path through which the antenna current flows when an antenna current is passed and operates as an antenna, and the ground plane 104 has a plurality of current paths having different directions and lengths. Can be generated.

  FIG. 3B shows the result of analyzing the VSWR characteristics of the antenna device 100 by simulation. Referring to FIG. 3B, in the GSM850 / 900 frequency band (0.824 to 0.894 GHz, 0.88 to 0.96 GHz) which is the current cellular band, it is generally desirable as a wireless communication device antenna. It can be seen that the specification <3 is satisfied. When the VSWR characteristic of the antenna device 100 shown in FIG. 3B is compared with the VSWR characteristic of the conventional antenna device 10 shown in FIG. 17, the band that satisfies the specification of VSWR <3 is widened. Recognize.

  Therefore, the antenna device 100 according to the first embodiment of the present invention can generate the multi-resonance mode by forming the ground plane 104 in a shape having a plurality of directions and current paths having different lengths. Without increasing the structure of the antenna device 100, it is possible to broaden the bandwidth that satisfies the specification of VSWR <3 compared to the conventional antenna devices 10 and 20.

(Second Embodiment)
Next, the configuration of the antenna device 200 according to the second embodiment of the present invention will be described in detail with reference to FIGS. 4 and 5.

  FIG. 4 is a diagram showing a schematic configuration of an antenna device 200 according to the second embodiment of the present invention, (a) is a perspective view showing a schematic configuration of the antenna device 200, and (b) is an antenna. 3 is a plan view showing a schematic configuration of the apparatus 200. FIG. FIG. 5 is a diagram for explaining the characteristics of the antenna device 200 shown in FIG. 4, and FIG. 5A is a diagram showing the current distribution of the ground plane 204 of the antenna device 200 shown in FIG. ) Is a graph showing the VSWR characteristics of the antenna device 200 shown in FIG.

  As illustrated in FIG. 4, the antenna device 200 includes an antenna element 201, a power feeding unit 203, and a ground plane 204. As illustrated, the antenna element 201, the power feeding unit 203, and the ground plane 204 are disposed on the inner side surface of the casing 202 that is a part of the case of the mobile communication terminal. The antenna element 201 is a folded L-type antenna having a 1 / 4λ electrical length. Hereinafter, the detailed description of the same configuration as the antenna device 100 according to the first embodiment of the antenna device 200 according to the second embodiment of the present invention will be omitted.

  The ground plane 204 has a shape that combines a plurality of patterns L6 to L12 having different shapes, as shown in FIG. As shown in FIG. 4B, the outer shape of the ground plane 204 is the same as the ground planes 14 and 24 in the conventional antenna devices 10 and 20, with a vertical length a2 = 100 mm and a horizontal length a3 = 50 mm. It is rectangular and includes notches k6 to k11. As illustrated, the notches k6 to k11 may have a shape combining a plurality of rectangular shapes having different shapes, a plurality of triangular shapes having different shapes, or a shape combining these shapes. The notches k6 to k11 are formed by being separated from each other by a predetermined distance, thereby forming a plurality of patterns L6 to L12 including a polygonal shape. As shown in FIG. 4A, the base plate 204 is formed such that the notches k6 and k8 are in contact with the side portions of the base plate 204, so that a part of the plurality of patterns L6 to L12 has a predetermined distance d5, Separated by d6.

  As illustrated in FIG. 4B, the width a1 of the antenna element 201 is 10 mm. Therefore, the antenna device 200 according to the second embodiment of the present invention can be formed in the same area (110 mm × 50 mm) as the area where the conventional antenna devices 10 and 20 described above are arranged.

  With reference to FIG. 5, the characteristics of the antenna device 200 according to the second embodiment of the present invention will be described in detail.

  FIG. 5A shows the result of analyzing the current distribution of the ground plane 204 when the antenna device 200 is operated at the center frequency using electromagnetic field simulation. As illustrated in FIG. 5A, the current path of the ground plane 204 in the antenna device 200 can take a plurality of current paths having different lengths in a plurality of directions.

  As shown in FIG. 5A, the ground plane 204 is configured to have a plurality of notches k6 to k11 (see FIG. 4), so that the gap between the notches k6 to k10 is sandwiched between the ground planes 204 on both sides. The generated electromagnetic field coupling can be adjusted. According to the notch k11 formed at a position close to the antenna element 201, the distance between the ground plane 204 and the antenna element 201 can be adjusted, and the ground plane 204 and the antenna can be adjusted. The impedance generated between the elements 201 can be adjusted. The ground plane 204 has a current path formed in the ground plane 204 by separating a part of the plurality of patterns L6 to L12 described above by the predetermined distances d5 and d6 (see FIG. 4) by the notches k6 and k8. Can be configured not to form a loop. By including such a configuration, the ground plane 204 can generate a plurality of current paths having different directions and lengths in the ground plane 104 when an antenna current is supplied to operate the ground plane 204.

  FIG. 5B shows the result of analyzing the VSWR characteristics of the antenna device 200 by simulation. Referring to FIG. 5B, in the GSM850 / 900 frequency band (0.824 to 0.894 GHz, 0.88 to 0.96 GHz) which is the current cellular band, it is generally desirable as an antenna for a wireless communication device. It can be seen that the specification <3 is satisfied. When the VSWR characteristic of the antenna device 200 shown in FIG. 5B is compared with the VSWR characteristic of the conventional antenna device 10 shown in FIG. 17, the band satisfying the specification of VSWR <3 is widened. Recognize.

  Therefore, the antenna device 200 according to the second embodiment of the present invention can generate a multi-resonance mode by forming the ground plane 204 in a shape having a plurality of directions and current paths having different lengths. Without increasing the structure of the antenna device 200, it is possible to broaden the bandwidth that satisfies the specification of VSWR <3 compared to the conventional antenna devices 10 and 20.

(Third embodiment)
Next, the configuration of the antenna device 300 according to the third embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 6 is a diagram showing a schematic configuration of an antenna device 300 according to the third embodiment of the present invention, (a) is a perspective view showing a schematic configuration of the antenna device 300, and (b) is an antenna. 4 is a plan view showing a schematic configuration of the apparatus 300. FIG. FIG. 7 is a diagram for explaining the characteristics of the antenna device 300 shown in FIG. 6, and FIG. 7A is a diagram showing the current distribution of the ground plane 304 of the antenna device 300 shown in FIG. ) Is a graph showing the VSWR characteristics of the antenna device 300 shown in FIG.

  As illustrated in FIG. 6, the antenna device 300 includes an antenna element 301, a power feeding unit 303, and a ground plane 304. As illustrated, the antenna element 301, the power feeding unit 303, and the ground plane 304 are arranged on the inner side surface of the casing 302 that is a part of the case of the mobile communication terminal. The antenna element 301 is a folded L-type antenna having a 1 / 4λ electrical length. Hereinafter, for the antenna device 300 according to the third embodiment of the present invention, detailed description of the same configuration as the antenna device 100 according to the first embodiment will be omitted.

  The ground plane 304 has a shape that is a combination of a plurality of patterns L13 to L17 having different shapes, as shown in FIG. As shown in FIG. 6B, the outer shape of the ground plane 304 is the same as the ground planes 14 and 24 in the conventional antenna devices 10 and 20, with a vertical length a2 = 100 mm and a horizontal length a3 = 50 mm. It has a rectangular shape and includes notches k12 to k16. As illustrated, the cutouts k12 to k16 may have a plurality of rectangular shapes having different shapes or a combination of these shapes. The notches k12 to k16 are formed at a predetermined distance from each other, thereby forming a plurality of patterns L13 to L17 including a rectangular shape. As shown in FIG. 6A, the base plate 304 is formed such that the notches k12 and k13 are in contact with the side portions of the base plate 304, so that a part of the plurality of patterns L13 to L17 has a predetermined distance d7, Separated by d8.

  As shown in FIG. 6B, the width a1 of the antenna element 301 is 10 mm. Therefore, the antenna device 300 according to the third embodiment of the present invention can be formed in the same area (110 mm × 50 mm) as the area where the conventional antenna devices 10 and 20 described above are arranged.

  With reference to FIG. 7, the characteristic of the antenna device 300 which concerns on the 3rd Embodiment of this invention is explained in full detail.

  FIG. 7A shows the result of analyzing the current distribution of the ground plane 304 when the antenna apparatus 300 is operated at the center frequency using electromagnetic field simulation. As illustrated in FIG. 7A, the current path of the ground plane 304 in the antenna device 300 can take a plurality of current paths having different lengths in a plurality of directions.

  As shown in FIG. 7A, the ground plate 304 is configured to have a plurality of notches k12 to k16 (see FIG. 6), so that the ground plates 304 on both sides of the notch k12 to k15 are sandwiched. The generated electromagnetic coupling can be adjusted, and according to the notch k16 formed at a position close to the antenna element 301, the distance between the ground plane 304 and the antenna element 301 can be adjusted, and the ground plane 304 and the antenna can be adjusted. The impedance generated between the elements 301 can be adjusted. The ground plane 304 has a current path formed in the ground plane 304 by separating a part of the plurality of patterns L13 to L17 described above by predetermined distances d7 and d8 (see FIG. 6) by the notches k12 and k13. It is possible to configure such that a part of the loop does not form a loop. By including such a configuration, the ground plane 304 can generate a plurality of current paths having different directions and lengths in the ground plane 304 when the ground plane 304 is operated as an antenna by flowing an antenna current.

  FIG. 7B shows the result of analyzing the VSWR characteristics of the antenna device 300 by simulation. Referring to FIG. 7B, in the GSM850 / 900 frequency band (0.824 to 0.894 GHz, 0.88 to 0.96 GHz), which is the current cellular band, VSWR generally desirable as an antenna for a wireless communication device. It can be seen that the specification <3 is satisfied. When the VSWR characteristic of the antenna device 300 shown in FIG. 7B and the VSWR characteristic of the conventional antenna device 10 shown in FIG. 17 are compared, the bandwidth satisfying the specification of VSWR <3 is widened. Recognize.

  Therefore, the antenna device 300 according to the third embodiment of the present invention can generate a multi-resonance mode by forming the ground plane 304 in a shape having a plurality of current paths having different lengths, and the antenna device can be generated. The bandwidth satisfying the specification of VSWR <3 can be made wider than that of the conventional antenna devices 10 and 20 without increasing the structure of 300.

(Fourth embodiment)
Next, the configuration of the antenna device 400 according to the fourth embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 8 is a diagram showing a schematic configuration of an antenna apparatus 400 according to the fourth embodiment of the present invention, (a) is a perspective view showing a schematic configuration of the antenna apparatus 400, and (b) is an antenna. 4 is a plan view showing a schematic configuration of the apparatus 400. FIG. FIG. 9 is a diagram for explaining the characteristics of the antenna device 400 shown in FIG. 8, and (a) is a diagram showing the current distribution of the ground plane 404 of the antenna device 400 shown in FIG. ) Is a graph showing the VSWR characteristics of the antenna device 400 shown in FIG.

  As illustrated in FIG. 8, the antenna device 400 includes an antenna element 401, a power feeding unit 403, and a ground plane 404. As shown in the figure, the antenna element 401, the power feeding unit 403, and the ground plane 404 are arranged on the inner side surface of the casing 402 that is a part of the case of the mobile communication terminal. The antenna element 401 is a folded L-type antenna having a 1 / 4λ electrical length. Hereinafter, the detailed description of the same configuration as the antenna device 100 according to the first embodiment of the antenna device 400 according to the fourth embodiment of the present invention will be omitted.

  The ground plane 404 has a shape that combines a plurality of patterns L18 to L20 having different shapes as shown in FIG. As shown in FIG. 8B, the outer shape of the ground plane 404 is the same length as the ground planes 14 and 24 in the conventional antenna devices 10 and 20, with a vertical length a2 = 100 mm and a horizontal length a3 = 50 mm. It has a rectangular shape and includes notches k17 and k18. The cutouts k17 and k18 may have a rectangular shape or a shape including a curve, as illustrated. The notches k17 and k18 are formed by being separated from each other by a predetermined distance, whereby a plurality of patterns L18 to L20 having a shape including a rectangular shape or a curved shape are formed. As illustrated in FIG. 8A, the base plate 404 is formed such that the notches k <b> 17 are in contact with the side portions of the base plate 404, whereby a part of the plurality of patterns L <b> 18 to L <b> 20 is separated by a predetermined distance d <b> 9. The

  As illustrated in FIG. 8B, the width a1 of the antenna element 401 is 10 mm. Therefore, the antenna device 400 according to the fourth embodiment of the present invention can be formed in the same area (110 mm × 50 mm) as the area where the conventional antenna devices 10 and 20 described above are arranged.

  With reference to FIG. 9, the characteristic of the antenna device 400 which concerns on the 4th Embodiment of this invention is explained in full detail.

  FIG. 9A shows the result of analyzing the current distribution of the ground plane 404 when the antenna apparatus 400 is operated at the center frequency using electromagnetic field simulation. As illustrated in FIG. 9A, the current path of the ground plane 404 in the antenna device 400 can take a plurality of current paths having different lengths in a plurality of directions.

  As shown in FIG. 9A, the ground plate 404 is configured to have a plurality of notches k17 and k18 (see FIG. 8), so that the ground plate 404 is generated between the ground plates 404 on both sides of the notch k17. The electromagnetic coupling can be adjusted, and the notch k18 formed at a position close to the antenna element 401 adjusts the distance between the ground plane 404 and the antenna element 401 so that the ground plane 404 and the antenna element 401 can be adjusted. The impedance generated between them can be adjusted. In addition, the ground plane 404 is one of the current paths formed in the ground plane 404 by separating a part of the plurality of patterns L18 to L20 described above by the notches k17 and k18 by a predetermined distance d9 (see FIG. 8). The part can be configured not to form a loop. By including such a configuration, the ground plane 404 can generate a plurality of current paths having different directions and lengths in the ground plane 404 when an antenna current is supplied to operate the ground plane 404 as an antenna.

  FIG. 9B shows the result of analyzing the VSWR characteristics of the antenna device 400 by simulation. Referring to FIG. 9B, in the frequency band (0.824 to 0.894 GHz, 0.88 to 0.96 GHz) of the current cellular band GSM850 / 900, it is generally desirable as an antenna for a wireless communication device. It can be seen that the specification <3 is satisfied. When the VSWR characteristic of the antenna device 400 shown in FIG. 9B is compared with the VSWR characteristic of the conventional antenna device 10 shown in FIG. 17, the band that satisfies the specification of VSWR <3 is widened. Recognize.

  Therefore, the antenna device 400 according to the fourth embodiment of the present invention can generate a multi-resonance mode by forming the ground plane 404 in a shape having a plurality of current paths having different directions and lengths. Without increasing the structure of the antenna device 400, it is possible to widen the bandwidth that satisfies the specification of VSWRVSWR <3, compared to the conventional antenna devices 10 and 20.

(Fifth embodiment)
Next, the configuration of the antenna device 500 according to the fifth embodiment of the present invention will be described in detail with reference to FIGS. 10 and 11.

  FIG. 10 is a diagram showing a schematic configuration of an antenna device 500 according to the fifth embodiment of the present invention, (a) is a perspective view showing a schematic configuration of the antenna device 500, and (b) is an antenna. 2 is a plan view showing a schematic configuration of a device 500. FIG. FIG. 11 is a diagram for explaining the characteristics of the antenna device 500 shown in FIG. 10, and FIG. 11A is a diagram showing the current distribution of the ground plane 504 of the antenna device 500 shown in FIG. ) Is a graph showing the VSWR characteristics of the antenna device 500 shown in FIG.

  As illustrated in FIG. 10, the antenna device 500 includes an antenna element 501, a power feeding unit 503, and a ground plane 504. As shown in the figure, the antenna element 501, the power feeding unit 503, and the ground plane 504 are disposed on the inner surface of the casing 502 that is a part of the case of the mobile communication terminal. The antenna element 501 is a folded L-type antenna having a 1 / 4λ electrical length. Hereinafter, the detailed description of the same configuration as the antenna device 100 according to the first embodiment of the antenna device 500 according to the fifth embodiment of the present invention will be omitted.

  The ground plane 504 has a shape in which a plurality of patterns L21 to L25 having different shapes are combined as shown in FIG. As shown in FIG. 10B, the outer shape of the ground plane 504 is the same as the ground planes 14 and 24 in the conventional antenna devices 10 and 20, with a vertical length a2 = 100 mm and a horizontal length a3 = 50 mm. It has a rectangular shape and includes notches k19 and k20. The cutouts k19 and k20 may have a rectangular shape or a combination of shapes including curves, as illustrated. The notches k19 and k20 are formed by being separated from each other by a predetermined distance, whereby a plurality of patterns L21 to L25 having a rectangular shape or a shape including a curve are formed. As shown in FIG. 10A, the base plate 504 is formed such that the notch k19 is in contact with the side portion of the base plate 504, whereby a part of the plurality of patterns L21 to L25 is separated by a predetermined distance d10. The

  As illustrated in FIG. 10B, the width a1 of the antenna element 501 is 10 mm. Therefore, the antenna device 500 according to the fifth embodiment of the present invention can be formed in the same area (110 mm × 50 mm) as the area where the conventional antenna devices 10 and 20 described above are arranged.

  With reference to FIG. 11, the characteristic of the antenna device 500 which concerns on the 5th Embodiment of this invention is explained in full detail.

  FIG. 11A shows the result of analyzing the current distribution of the ground plane 504 when the antenna apparatus 500 is operated at the center frequency using electromagnetic field simulation. As illustrated in FIG. 11A, the current path of the ground plane 504 in the antenna device 500 can take a plurality of current paths having different lengths in a plurality of directions.

  As shown in FIG. 11A, the ground plane 504 is formed between the ground planes 504 on both sides of the notch k19 by configuring the ground plane 504 to have a plurality of notches k19 and k20 (see FIG. 10). The electromagnetic coupling can be adjusted, and according to the notch k20 formed at a position close to the antenna element 501, the distance between the ground plane 504 and the antenna element 501 is adjusted, and the ground plane 504 and the antenna element 501 are adjusted. The impedance generated between them can be adjusted. In addition, the ground plane 504 has a part of the current path formed in the ground plane 504 by separating a part of the plurality of patterns L21 to L25 described above by the notch k19 by a predetermined distance d10 (see FIG. 10). It can be configured not to form a loop. By including such a configuration, the ground plane 504 can generate a plurality of current paths having different directions and lengths in the ground plane 504 when an antenna current is supplied to operate as the antenna.

  FIG. 11B shows the result of analyzing the VSWR characteristics of the antenna device 500 by simulation. Referring to FIG. 11B, in the frequency band (0.824 to 0.894 GHz, 0.88 to 0.96 GHz) of the current cellular band GSM850 / 900, VSWR is generally desirable as an antenna for a wireless communication device. It can be seen that the specification <3 is satisfied. When the VSWR characteristic of the antenna device 500 shown in FIG. 11B is compared with the VSWR characteristic of the conventional antenna device 10 shown in FIG. 17, the band satisfying the specification of VSWR <3 is widened. Recognize.

  Therefore, the antenna device 500 according to the fifth embodiment of the present invention can generate a multi-resonance mode by forming the ground plane 504 in a shape having a plurality of current paths having different directions and lengths. Without increasing the structure of the antenna device 500, it is possible to broaden the band that satisfies the specification of the VSWR characteristic <3 compared to the conventional antenna devices 10 and 20.

(Sixth embodiment)
Next, the configuration of the antenna device 600 according to the sixth embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 12 is a diagram showing a schematic configuration of an antenna device 600 according to the sixth embodiment of the present invention, (a) is a perspective view showing a schematic configuration of the antenna device 600, and (b) is an antenna. 3 is a plan view showing a schematic configuration of an apparatus 600. FIG. FIG. 13 is a diagram for explaining the characteristics of the antenna device 600 shown in FIG. 12, and (a) is a diagram showing the current distribution of the ground plane 604 of the antenna device 600 shown in FIG. ) Is a graph showing the VSWR characteristics of the antenna device 600 shown in FIG.

  As illustrated in FIG. 12, the antenna device 600 includes an antenna element 601, a power feeding unit 603, and a ground plane 604. As shown in the figure, the antenna element 601, the power feeding unit 603, and the ground plane 604 are disposed on the inner surface of the housing 602 that is a part of the case of the mobile communication terminal. The antenna element 601 is a folded L-type antenna having a 1 / 4λ electrical length. Hereinafter, the detailed description of the same configuration as the antenna device 100 according to the first embodiment of the antenna device 600 according to the sixth embodiment of the present invention will be omitted.

  The ground plane 604 has a shape in which a plurality of patterns L26 to L28 having different shapes are combined, as illustrated by being divided by dotted lines in FIG. As shown in FIG. 12 (b), the outer shape of the ground plane 604 is the same size as the ground planes 14 and 24 in the conventional antenna devices 10 and 20, with the vertical length a2 = 100 mm and the horizontal length a3 = 50 mm. It has a rectangular shape and includes notches k21 and k22. As illustrated, the notches k21 and k22 may have a rectangular shape or a shape including a curved shape. The notches k21 and k22 are formed by being separated from each other by a predetermined distance, thereby forming a plurality of patterns L26 to L28 having a shape including a rectangular shape or a curved shape. As illustrated in FIG. 12A, the base plate 604 is formed such that the notches k21 and k22 are in contact with the side portions of the base plate 604, so that a part of the plurality of patterns L26 to L28 has a predetermined distance d11, Separated by d12.

  As illustrated in FIG. 12B, the width a1 of the antenna element 601 is 10 mm. Therefore, the antenna device 600 according to the sixth embodiment of the present invention can be formed in the same area (110 mm × 50 mm) as the area where the conventional antenna devices 10 and 20 described above are arranged.

  The characteristics of the antenna device 600 according to the sixth embodiment of the present invention will be described in detail with reference to FIG.

  FIG. 13A shows the result of analyzing the current distribution of the ground plane 604 when the antenna apparatus 600 is operated at the center frequency using electromagnetic field simulation. As illustrated in FIG. 13A, the current path of the ground plane 604 in the antenna device 600 can take a plurality of current paths having different lengths in a plurality of directions.

  As shown in FIG. 13A, the ground plane 604 is configured to have a plurality of notches k21 and k22 (see FIG. 12), so that the ground planes 604 on both sides sandwiching the notches k21 and k22. The generated electromagnetic field coupling can be adjusted, and according to the notch k22 formed at a position close to the antenna element 601, the distance between the ground plane 604 and the antenna element 601 can be adjusted, and the ground plane 604 and the antenna can be adjusted. The impedance generated between the elements 601 can be adjusted. The ground plane 604 has a current path formed in the ground plane 604 when a part of the plurality of patterns L26 to L28 described above is separated by a predetermined distance d11, d12 (see FIG. 12) by the notches k21 and k22. It is possible to configure such that a part of the loop does not form a loop. By including such a configuration, the ground plane 604 can generate a plurality of current paths having different directions and lengths in the ground plane 604 when an antenna current is supplied to operate as the antenna.

  FIG. 13B shows the result of analyzing the VSWR characteristics of the antenna device 600 by simulation. Referring to FIG. 13B, in the GSM850 / 900 frequency band (0.824 to 0.894 GHz, 0.88 to 0.96 GHz), which is the current cellular band, VSWR is generally desirable as an antenna for a wireless communication device. It can be seen that the specification <3 is satisfied. When the VSWR characteristic of the antenna device 600 shown in FIG. 13B is compared with the VSWR characteristic of the conventional antenna device 10 shown in FIG. 17, the band satisfying the specification of VSWR <3 is widened. Recognize.

  Therefore, the antenna device 600 according to the sixth embodiment of the present invention can generate a multi-resonance mode by forming the ground plane 604 into a shape having a plurality of directions and current paths having different lengths. Without increasing the structure of the antenna device 600, it is possible to broaden the bandwidth that satisfies the specification of VSWR <3 as compared to the conventional antenna devices 10 and 20.

FIG. 14 shows a comparative diagram comparing the VSWR characteristics of the antenna devices 100 to 600 according to the first to sixth embodiments of the present invention as described above and the VSWR characteristics of the conventional antenna devices 10 and 20. As shown in FIG. 14, the antenna devices 100 to 600 according to the first to sixth embodiments of the present invention have a larger structure of the antenna devices 100 to 600 than the conventional antenna devices 10 and 20. It can be seen that good electrical characteristics can be obtained in a wide band without doing so.

100, 200, 300, 400, 500, 600: antenna devices 101, 201, 301, 401, 501, 601: antenna elements 103, 203, 303, 403, 503, 603: power feeding units 104, 204, 304, 404, 504, 604: Main plate 102, 202, 302, 402, 502, 602: Housing

Claims (7)

With the main plate,
An antenna element arranged at an end of the ground plane;
A power feeding unit disposed between the ground plane and the antenna element,
The antenna device according to claim 1, wherein the ground plane has a plurality of current paths through which an antenna current flowing through the antenna element by power feeding from the power feeding section flows in a plurality of directions and paths having different lengths.   The antenna device according to claim 1, wherein the ground plane forms the plurality of current paths by combining a plurality of patterns having different shapes.   The antenna device according to claim 2, wherein the ground plane forms the plurality of current paths by separating a part of the plurality of patterns having different shapes from each other by a predetermined distance.   The antenna device according to claim 2 or 3, wherein the ground plane includes a pattern having a plurality of different shapes.   The antenna device according to any one of claims 2 to 4, wherein the ground plane includes a pattern having a shape in which the plurality of patterns having different shapes include a curve.   The antenna device according to claim 1, wherein the antenna element is a folded L-type antenna. An antenna device according to any one of claims 1 to 6, comprising:
A radio communication apparatus, wherein the antenna element and the ground plane are arranged on an inner surface of a casing.