The present invention relates to an antenna, and more particularly to an antenna that is formed on a substrate, and a wireless communication apparatus using the same.
In order to miniaturize an antenna, the volume of the antenna conductor is preferably made smaller. In order to reduce the volume of the antenna conductor, grounded antennas are typically used. Typical examples of antennas include an L-type antenna and an inverted F-type antenna. The L-type antenna has an antenna conductor which is bent in the middle to reduce the distance between the antenna conductor and the ground. The inverted F-type antenna has an antenna conductor which is grounded at one end.
For example, when a game apparatus and a game controller perform wireless communications with each other, both the units are provided with an antenna. In particular, since the game controller size is small, miniaturization of the antenna to be mounted thereon is also required. Despite being small-sized, the game controller is also required to implement various functions, and it is therefore desirable to make effective use of any available space. Moreover, since the game controller is hand held, radiations toward the human body are shielded. It is therefore desirable to make effective use of the radiation power of the antenna.
The present invention has been developed in view of the foregoing circumstances, and a general purpose thereof is to provide a technology for efficient layout of an antenna while ensuring a desired antenna directivity.
To solve the foregoing problems, an antenna according to an embodiment of the present invention includes: an antenna area which is formed on a corner of a substrate; an antenna conductor which is formed in the antenna area and is shaped so that its first conductor part and second conductor part are connected to each other via a bend; a first ground area which is formed next to the antenna area and is connected to an end of the first conductor part; a second ground area which is formed next to the antenna area and is spaced away from an end of the second conductor part in a direction from the bend to the end of the second conductor part; and a feed unit which feeds electricity to the antenna conductor.
According to this embodiment, a low-profile grounded antenna is provided on the corner of the substrate, and the second ground area is formed near the second conductor part. This configuration makes it possible to lay out the antenna efficiently and ensure a desired antenna directivity as well.
Another embodiment of the present invention is a wireless communication apparatus. This apparatus includes an antenna and a communication unit which performs wireless communication through the antenna. The antenna includes: an antenna area which is formed on a corner of a substrate; an antenna conductor which is formed in the antenna area and is shaped so that its first conductor part and second conductor part are connected to each other via a bend; a first ground area which is formed next to the antenna area and is connected to an end of the first conductor part; a second ground area which is formed next to the antenna area and is spaced away from an end of the second conductor part in a direction from the bend to the end of the second conductor part; and a feed unit which feeds electricity to the antenna conductor.
According to this embodiment, the wireless communication apparatus is provided with a low-profile grounded antenna which is arranged on the corner of the substrate, and the second ground area is formed near the second conductor part. This configuration makes it possible to lay out the antenna efficiently and ensure a desired antenna directivity as well.
Yet another embodiment of the present invention is also a wireless communication apparatus. This apparatus is a wireless communication apparatus having a grounded antenna. The grounded antenna includes: an antenna conductor whose open end is located in a position not covered by user's hands when the user performs ordinary operations; and a ground area which is formed near the open end of the antenna conductor.
According to this embodiment, the end of the antenna conductor is located in a position not covered by the user's hands. This can reduce the influence of the user's hands on the antenna directivity.
According to the present invention, it can lay out the antenna efficiently and ensure a desired antenna directivity as well.
An embodiment of the present invention relates to a game controller which is connected to a game apparatus by a wireless line. In particular, the embodiment relates to an antenna which is arranged inside the game controller. The game apparatus includes the functions of reproducing an optical disc, a recording medium on which a game program is recorded, and displaying game characters and background images on the screen of a television set according to the game program. The game controller accepts user operations, and controls the operation of the game apparatus, thereby running the game software recorded on the optical disc. The antenna to be provided in such a game controller requires miniaturization. For effective use of the space inside the game controller, the antenna also requires an efficient layout. Moreover, since the game controller is supposed to be hand held, the human body is naturally located behind the game controller. The directivity is thus desirably lowered in that direction and enhanced in the forward direction, away from the user's body. Under the circumstances, an antenna according to the present embodiment is configured as described below.
The direction buttons 8 protrude from the top of the game controller 100 and are arranged orthogonal to each other. Moreover, the four direction buttons 8 are integrally connected to each other. For example, the direction buttons 8 function as a directional instruction control unit for controlling the movement of a display character. Pressing the first to fourth direction buttons 8a to 8d moves the display character in the arranging directions of the direction buttons 8 pressed.
The instruction buttons 10 are also arranged orthogonal to each other. The first to fourth instruction buttons 10a to 10d are formed as separate respective members. The instruction buttons 10 are provided with corresponding switch elements which serve as signal input devices. For example, when the first to fourth instruction buttons 10a to 10d are pressed to turn on the corresponding switches, various functions of the display character assigned to the respective instruction buttons 10 are performed.
The rotational operators 12 are arranged in opposing positions at the base-side corners of the first grip 2 and the second grip 4. The rotational operators 12 are rotatable 360° about their spindles, and are operated to activate signal input devices such as variable resistive elements. More specifically, the rotational operators 12 are attached to the extremities of spindles which are mounted so as to return to their neutral positions by means of a urging member, and are rotationally operated 360° about the rotating centers of the spindles. The rotational operators 12 can be rotated to achieve analog motions such as moving a display character with rotation, moving it with a change in speed, and changing the shape of the character.
The start switch 16 is positioned between the direction buttons 8 and the instruction buttons 10, and is intended to initiate a game. The select switch 14 is used to make a selection such as a game level, for example, when starting the game.
Holding the first grip 2 and the second grip 4 in the palms of both hands eliminates the need to support the game controller 100 with thumbs and fingers. That is, the game controller 100 can be held so that a maximum of two thumbs and eight fingers of the hands, or at least two thumbs and four fingers, are freely movable. In
These rotational operators 12, direction buttons 8, and instruction buttons 10 can be pressed selectively. In particular, the rotational operators 12 are arranged in opposite positions on the base-sides of the first and second grips 2 and 4 which are held in the palms of the hands. The rotational operators 12 are thus positioned closest to the thumbs of the right and left hands when the first grip 2 and the second grip 4 are held by the hands. This facilitates rotating the rotational operators 12 with the thumbs of the right and left hands.
It should be appreciated that the body of the person who operates the game controller 100 is located behind the game controller 100 shown in
As shown in
As shown in
The communication unit 32 performs wireless communication through the antenna 30. That is, the communication unit 32 performs encoding, modulation, and frequency conversion as transmission functions, and performs frequency conversion, demodulation, and decoding as reception functions. The communication functions of the communication unit 32 correspond to those of the not-shown game apparatus. Since the communication unit 32 is formed in the game controller 100, it transmits and receives information pertaining to game operations.
The operation unit 38 accepts information pertaining to game operations. The operation unit 38 corresponds to the direction buttons 8, the instruction buttons 10, the rotational operators 12, the select switch 14, and the start switch 16 of
In terms of hardware, the foregoing configuration can be achieved by an arbitrary computer CPU, a memory, and other LSIs. In terms of software, it can be achieved by a program which is loaded in a memory. The functional blocks shown here are practiced by the cooperation of such. It will thus be understood by those skilled in the art that these functional blocks may be practiced in various forms including hardware alone, software alone, or by using a combination thereof.
The antenna area 52 is positioned in the front left area of the substrate 50. The antenna area 52 is formed next to the ground area 54. The antenna area 52 also has a rectangular shape, and the border between the antenna area 52 and the ground area 54 is shown by a first borderline 80 and a second borderline 82 which are orthogonal to each other, as shown in
The antenna conductor 56 is formed in the antenna area 52 on the substrate 50. The antenna conductor 56 has a shape such that a bend 62 is formed between the ground end 58 and the open end 60, i.e., an “L” shape is formed. In this instance, the antenna conductor 56 shall be bent into a right angle at the bend 62. For ease of description, the part of the antenna conductor 56 extending from the ground end 58 to the bend 62 will be referred to as a first conductor part 90. The part extending from the bend 62 to the open end 60 will be referred to as a second conductor part 92.
The shape of the antenna conductor 56 is equivalent to that of the first conductor part 90 and the second conductor part 92 which are orthogonally connected to each other at the bend 62. The ground end 58 is connected to the first ground area 94 while the open end 60 is positioned near the second borderline 82. That is, the open end 60 is positioned closer to the center of the substrate 50 than the bend 62 is, when viewed from the left side edge 42. In this instance, the center of the substrate 50 shall refer to the midpoint between the left side edge 42 and the right side edge 44. In the foregoing configuration, the first conductor part 90 is arranged in parallel with the second borderline 82 and the left side edge 42. The second conductor part 92 is arranged in parallel with the first borderline 80 and the front edge 40.
The ground area 54 is formed on the substrate 50, and is composed of the first ground area 94 and the second ground area 96 as shown in the diagram. For ease of description, the ground area 54 shall be formed as a continuous area on the substrate 50, occupying the entire area of the substrate 50 other than the antenna area 52. The first ground area 94 is formed to adjoin and lie behind the antenna area 52. The border between the first ground area 94 and the antenna area 52 corresponds to the first borderline 80. The first ground area 94 is connected to the ground end 58. Meanwhile, the second ground area 96 is formed to adjoin the antenna area 52 so as to cover the right side of same. More specifically, the second ground area 96 is spaced away from the open end 60 of the second conductor part 92 in the direction from the bend 62 to the open end 60. The second ground area 96 is formed along the front edge 40 of the substrate 50. When viewed in the direction from the front edge 40 to the rear edge 46, the second ground area 96 has only to have a length at least capable of mirroring the forefront conductor out of the conductors formed in the antenna area 52. In this instance, the foremost conductor corresponds to the second conductor part 92. The border between part of the second ground area 96 and the antenna area 52 corresponds to the second borderline 82.
The feed unit 66 feeds electricity to the antenna conductor 56 through the feed line 64. The feed line 64 is formed in parallel with the first conductor part 90 of the antenna conductor 56, and is connected to the second conductor part 92 of same.
In the foregoing configuration, the antenna conductor 56 and the feed line 64 are arranged in an “inverted F” shape. These conductors and the first ground area 94 thus constitute an inverted F-type grounded antenna. It should be appreciated that the inverted F-type grounded antenna provides a higher field intensity at the open end 60 than at the bend 62. In this instance, the bend 62 of relatively low field intensity is arranged on the left side in the antenna area 52, i.e., near the left side edge 42. Meanwhile, the open end 60 of relatively high field intensity is arranged on the right side in the antenna area 52, i.e., near the second borderline 82. This can situate the open end 60 in a position not covered by the left hand. Consequently, it is possible to create a high field intensity in the center area of the substrate, thereby reducing the shielding effect of human hands and maintaining the forward directivity of the antenna.
In addition to this, an image of the inverted F-type grounded antenna is formed in the second ground area 96. The right ground area thus provides the antenna directivity of the image. The antenna directivity from the inverted F-type grounded antenna and the antenna directivity from the image are also superimposed on each other to enhance forward directivity. In the foregoing configuration, the second conductor part 92 of the antenna conductor 56 is designed to have a length approximately λ/4. In this instance, λ represents the wavelength of the radio waves in use. The lateral length of the second ground area 96, i.e., the distance from the right end of the ground area 54 to the second borderline 82 is at least approximately λ/4. Consequently, only the length of the substrate 50 from the left side edge 42 to the right side edge 44 has to be at least approximately λ/2, which allows miniaturization of the substrate 50.
As described previously, the inverted F-type grounded antenna provides a higher field intensity at the open end 160 than at the bend 162. In this instance, the open end 160 of
The substrate 250 shown in
The director 68 is arranged generally in parallel with the second conductor part 92 of the antenna conductor 56. In this instance, “generally in parallel” refers to situations where most of the director 68 is roughly in parallel, however it should be appreciated that complete parallelism is not required. The director 68 functions to direct the antenna pattern formed by the foregoing inverted F-type grounded antenna further forward. Furthermore, since the second ground area 96 lies in the longitudinal direction of the director 68, an image of the director 68 can be formed in the second ground area 96.
Consequently, even if the director 68 length is small, the image length can be added to make the director 68 substantially longer. As a result, it is possible to direct the antenna pattern further forward. It should be appreciated that while the second ground area 96 in
Part of the director 68 lying close to the open end 60, i.e., the part close to the second borderline 82 makes a capacitor part 70. In this instance, the capacitor part 70 is bent generally in parallel with the second borderline 82. That is, the director 68 has an “L” shape. The capacitor part 70 of the director 68 forms a capacitor with the opposing second ground area 96, i.e., the area in the vicinity of the second borderline 82. This capacitor makes it possible to reduce the length of the wave director or the length of the second ground area 96.
A resonance frequency F0 is given by the following equation:
F0=1/(2π√(L1+L2)C),
where L1 is the inductance of the director 68, L2 is the inductance of a part corresponding to the image of the director 68 in the second ground area 96, and C is the capacitance of the capacitor.
Therefore, even if L1 and L2 are reduced, it is possible to maintain the value of FO by adjusting C. Consequently, the antenna pattern can be directed forward even when the length of the substrate 50 shown in
The substrate 50 shown in
The substrate 50 shown in
According to the embodiment of the present invention, the open end of the antenna conductor is located in a position not covered by the hands. This can prevent the antenna gain from dropping due to shielding by the hands. Since the open end of the antenna conductor is not directed toward any edges of the substrate, it is possible to reduce the effect of foreign factors on the antenna characteristics. Moreover, since the open end of the antenna conductor is directed toward the ground area, the antenna directivity can be directed forward because of superimposition of the image with the ground area. The use of the image superimposition also allows a reduction in the length of the antenna conductor. The reduced length of the antenna conductor also makes it possible to miniaturize the antenna. The use of the wave director and its image also makes it possible to direct the antenna directivity forward and miniaturize the substrate as well. Moreover, since the wave director is bent at the position near the ground area, a capacitor can be formed between the wave director and the ground area.
The formation of the capacitor allows reduction in the lengths of the wave director and the ground area. The reduced length of the wave director and the ground area also makes it possible to miniaturize the antenna. Furthermore, the formation of the component mounting area inside the ground area allows miniaturization of the entire apparatus. When either one or both of the antenna conductor and the wave director are formed in a meandering shape, it is possible to reduce the length of either one or both of the antenna conductor and the wave director. When either one or both of the antenna conductor and the wave director are provided with a chip coil, it is possible to reduce the length of either one or both of the antenna conductor and the wave director.
Up to this point, the present invention has been described in conjunction with the embodiment thereof. It should be appreciated that these embodiments are provided solely by way of illustration only. It will be understood by those skilled in the art that various modifications may be made to combinations of the foregoing components and processes, and all such modifications are also intended to fall within the scope of the present invention.
The embodiments have dealt with the case where the antenna area 52 is formed in the left part of the substrate 50. This is not restrictive, however. The antenna area 52 may be formed in the right part of the substrate 50 also. In that case, the components shown in the embodiments shall be arranged in a horizontally symmetrical pattern. According to this modification, it is possible to improve the degree of freedom in antenna design. In essence, only the antenna area 52 has to be formed on a corner of the substrate 50.
The embodiments have dealt with the case where the antenna conductor 56, the feed line 64, the feed unit 66, and the first ground area 94 form the inverted F-type grounded antenna. This is not restrictive, however. An inverted L grounded antenna may be formed with the antenna conductor 56, the feed unit 66, and the first ground area 94. In that case, the feed unit 66 is connected to the ground end 58 of the antenna conductor 56. According to this modification, it is possible to improve the degree of freedom in antenna design. In essence, only a low-profile grounded antenna has to be used.
The embodiments have dealt with the case where the first borderline 80 and the second borderline 82 are orthogonal to each other. This is not restrictive, however. The two borderlines need not necessarily be orthogonal. The angle between the two borderlines, i.e., the shape of the antenna area 52 may be designed depending on the shape of the substrate 50 and the antenna characteristics required. The same holds for the first conductor part 90 and the second conductor part 92. According to this modification, it is possible to improve the degree of freedom in antenna design. That is, only the low-profile grounded antenna has to be designed for proper function.
The embodiments have dealt with the case where the substrate 50 is mounted on the game controller 100. This is not restrictive, however. For example, the substrate 50 may be mounted on other communication apparatuses. According to this modification, it is possible to apply the substrate 50 to various types of apparatuses. In essence, only the substrate 50 has to be applied to an apparatus that performs wireless communications.
The embodiments have dealt with the case where the component mounting area 72 is formed behind the second ground area 96 in
According to the present invention, it can lay out the antenna efficiently and ensure a desired antenna directivity as well.
Number | Date | Country | Kind |
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2006-103881 | Apr 2006 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2007/000370 | 4/5/2007 | WO | 00 | 1/29/2009 |