JP2009212971A - Radio apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure a gain, in a predetermined direction, of an antenna that is incorporated in a case of a radio apparatus formed while containing a conductive material such as a metal. <P>SOLUTION: In the first case 11 of the radio apparatus 1, a display part 14 is mounted on the front, and a display surrounding part 11a around the display part 14 is formed from a metal. An antenna 20, of which the distal end is open, is connected to a power feeding point 19 provided on a first substrate 15 incorporated in the first case 11. A hole 17 is provided at one position of the display surrounding part 11a, and the antenna 20 is disposed so as to position its distal end inside the hole 17 when the radio apparatus 1 is viewed from a direction approximately perpendicular to a surface formed from the display surrounding part 11a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless device, and more particularly to a wireless device having an antenna built in a housing.

  Wireless devices such as mobile phones are being made smaller, thinner, and lighter (so-called lighter, thinner and shorter). As part of this, not only a liquid crystal display (LCD) but also a thin device such as an organic electroluminescence (EL) has been put into practical use for a display device attached to the surface of a casing of a wireless device.

  In order to maintain the mechanical strength of the housing even when such a thin display device is attached, it is useful to form at least a portion of the housing surrounding the display device with metal. In addition to this example, there is also known one in which a substantial part or all of the casing is made of metal.

  By the way, as another element important for making the wireless device lighter, thinner, and smaller, it is possible to include an antenna in the housing. The form of the wireless device with a built-in antenna is superior to the conventional form in which a part or a substantial part of the antenna protrudes or is pulled out of the housing, and is smarter in appearance and easier to handle. It is useful for conversion.

  However, when the antenna is built in a housing made of metal, there is a problem that it is difficult to obtain a required radiation pattern characteristic because the housing acts as a radio wave shield. Conventionally, such problems have been examined not only in mobile phones but also in the fields of personal computers equipped with wireless communication functions, hands-free call devices in automobiles, etc. (see, for example, Patent Document 1 or Patent Document 2).

  In the technique disclosed in Patent Document 1 described above, when an antenna is disposed in an electronic device having a display unit such as a personal computer in a conductive casing, the antenna is attached to the back of the display panel, and the antenna of the display unit casing is provided. By providing an opening around the mounting area, a gain in the opening direction is ensured.

The technique disclosed in Patent Document 2 described above is based on a metal housing located in front of an antenna element of a wireless device when a vehicle interior wireless device is provided in a metal housing of a dashboard for a hands-free call in an automobile. The gain in the direction of the opening is ensured by forming the opening in this portion.
JP 2002-196837 A (2nd and 3rd pages, FIG. 1) JP 2003-324302 A (2nd, 5th, 6th pages, FIG. 3)

  The conventional technique disclosed in Patent Document 1 or Patent Document 2 described above is applied to an apparatus that is larger in size than a mobile phone or the like and has a sufficient mounting space. Therefore, Patent Document 1 or Patent Document 2 describes that the size of the opening and the positional relationship with the antenna are not finely defined, or that the size of the opening is about one wavelength of the use frequency.

  However, in some cases, such as a cellular phone, a wireless device having a size shorter than the wavelength has such a problem that such a method of definition is only rough and cannot be applied.

  The present invention has been made to solve the above problem, and provides a radio apparatus capable of ensuring a gain in a predetermined direction of an antenna built in a housing formed of a conductive material such as metal. The purpose is to do.

  In order to achieve the above object, a wireless device of the present invention includes a housing that is perforated in a part of one surface formed of a conductive material, and is incorporated in the housing. A portion in the vicinity of a portion having a resonance frequency that is connected to a provided feeding point and has a resonance frequency determined by a size, and where a voltage maximum value is distributed when the feeding is performed at the resonance frequency is a surface of the casing 1. And an antenna disposed so as to be located inside the perforation when viewed from a direction substantially perpendicular to the perforation.

  According to the present invention, it is possible to secure a gain in a predetermined direction of the built-in antenna by perforating a part of the conductive material of the housing of the wireless device and selecting the positional relationship between the perforation and the antenna built-in the housing. it can.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In addition, when referring to the following figures, up, down, left, right, horizontal, vertical (vertical) means up, down, left, right, horizontal, vertical (vertical) on the paper on which the figure is represented, unless otherwise specified. . Moreover, the code | symbol common between each figure shall represent the same structure.

  FIG. 1 is a diagram illustrating a main configuration of a wireless device 1 according to an embodiment of the present invention. As an example, the wireless device 1 is a mobile phone configured such that a first housing 11 and a second housing 12 are engaged with each other through a connection portion 13 so as to be opened and closed. Note that the opening and closing of the first housing 11 and the second housing 12 may be performed by a biaxial hinge type, a slide type, or other methods in addition to the folding type method illustrated in FIG. Note that the number of housings constituting the wireless device 1 is not limited to 2, and may be 1 or 3 or more.

  For example, liquid crystal or organic electroluminescence (EL) is provided on the front surface of the first housing 11 (the surface facing the user when the first housing 11 and the second housing 12 are opened and used). The display part 14 which consists of a device like this is attached. Since the display unit 14 is configured to be thin, at least a portion (referred to as a display peripheral unit 11a) surrounding the display unit 14 of the first casing 11 hatched in FIG. It is made of a metal (conductive material) such as magnesium.

  The first housing 11 incorporates a first substrate 15 represented by a broken line. The second housing 12 incorporates a second substrate 16 represented by a broken line. A perforation 17 is provided in a part above the display peripheral portion 11a. The perforations 17 are holes from which metal has been removed, and may be filled with a dielectric material or the like for dust prevention.

  FIG. 2 is a diagram (side view) illustrating the positional relationship of the main components included in the first housing 11 as viewed in the direction of the block arrow illustrated in FIG. 1. The configurations denoted by reference numerals 11 to 17 in FIG. 2 are the same as those shown in FIG.

  A power feeding point 19 that is electrically connected to a radio circuit (not shown) provided on the first substrate 15 or the second substrate 16 is provided in a part above the first substrate 15. An antenna 20 connected to the feeding point 19 is disposed above the first housing 11. In the present embodiment, the antenna 20 is, for example, a global positioning system (GPS) receiving antenna having directivity in a direction substantially perpendicular to the surface formed by the display peripheral portion 11a (opposite to the block arrow in FIG. 2). Assume that securing is required.

  FIG. 3 is a diagram (front view) showing the positional relationship of the main components included in the first housing 11 in the direction of the block arrow shown in FIG. 2 (from a direction substantially perpendicular to the surface formed by the display peripheral portion 11a). Figure). The configurations denoted by reference numerals 11a to 20 in FIG. 3 are the same as those in FIG. 1 or FIG. The first substrate 15 is indicated by a broken line.

  As shown in FIG. 3, one end of the antenna 20 is connected to the feeding point 19 and the other end is open (referred to as an open end). The open end of the antenna 20 is located inside the perforation 17 when viewed from a direction substantially perpendicular to the surface formed by the display peripheral portion 11a.

  A configuration in which a perforation 17 is provided in the display peripheral portion 11a of the wireless device 1 and the open end of the antenna 20 is positioned inside the perforation 17 when viewed from a direction substantially perpendicular to a surface formed by the display peripheral portion 11a. The effect of will be described with reference to FIGS. FIG. 4 shows a measurement example of the antenna radiation pattern of the wireless device 1 as a solid curve when viewed from the direction of the block arrow in FIG. 1, and a measurement example in the case where the perforations 17 are not provided in the metal display peripheral portion 11a. For comparison, FIG.

  The concentric circles in FIG. 4 represent the power level of the antenna radiation pattern of the wireless device 1 placed at the center in 5 decibel (dB) steps. The direction of looking upward from the center of the concentric circle substantially corresponds to the direction substantially perpendicular to the surface formed by the display peripheral portion 11a. In this direction, it can be seen that the solid line radiation pattern is improved by about 4 dB compared to the broken line radiation pattern. It can also be seen that the solid line radiation pattern is generally improved in other directions as compared with the broken line radiation pattern.

  FIG. 5 is a Smith diagram illustrating an example of measurement of impedance characteristics of the antenna 20 of the wireless device 1 and a diagram illustrating an example of measurement of frequency characteristics of the voltage standing wave ratio (VSWR) viewed from the feeding point 19. The horizontal axis of the VSWR graph represents the frequency (range from 1 gigahertz (GHz) to 2 GHz, 0.1 GHz step), and the vertical axis represents the value of VSWR (range from 1 to 11, 1 step).

  FIG. 6 is a diagram illustrating measurement examples of impedance characteristics and VSWR characteristics similar to those in FIG. 5 when the perforations 17 are not provided in the metal display peripheral portion 11a. The horizontal and vertical axes of the VSWR graph are the same as those in FIG. When FIG. 5 is compared with FIG. 6, there is no significant difference in the measurement results, and it can be seen that the presence or absence of the perforations 17 in the display peripheral portion 11a does not affect the impedance characteristics and VSWR characteristics of the antenna.

  7 to 9, the shape of the perforations 17 and the positional relationship with respect to the antenna 20 and the improvement of the antenna radiation pattern in a direction substantially perpendicular to the surface formed by the display peripheral portion 11a (described with reference to FIG. 4). Thus, an example in which the relationship with the case where the perforations 17 are not provided is evaluated by simulation will be described. FIG. 7 is divided into a case where the perforations 17 are not provided (all the display peripheral portion 11a is made of metal such as magnesium), a case where the perforations 17 are square, and a case where the perforations 17 are circular (horizontal axis). FIG. 4 is a diagram illustrating a simulation example for comparing the antenna radiation pattern improvement levels (represented in dB on the vertical axis).

  As a simulation condition, the antenna 20 has the same inverted L shape as that shown in FIG. 3, and the vertical and horizontal lengths thereof are 15 millimeters (mm) and 28 mm, respectively. The frequency is about 1.5 GHz. When the antenna 20 is viewed from a direction substantially perpendicular to the surface formed by the display peripheral portion 11a, the range from the open end to the 1 / 100th wavelength is located inside the perforation 17.

  According to the simulation example shown in FIG. 7, it can be seen that the difference in the shape of the perforations 17 (square or circular) does not significantly affect the improvement level of the antenna radiation pattern.

  FIG. 8 shows how far the element length range including the open end of the antenna 20 is located inside the perforation 17 when viewed from a direction substantially perpendicular to the surface formed by the display peripheral portion 11a (the wavelength ( It is a figure showing the example of a simulation which evaluates the level of improvement of an antenna radiation pattern (it expresses in the unit of dB on a vertical axis) by a length on the basis of (represented by symbol λ). Among the simulation conditions, the shape, size, and frequency of the antenna 20 are the same as those in FIG. The shape of the perforations 17 is a square.

  According to the simulation example shown in FIG. 8, when the wireless device 1 is viewed from a direction substantially perpendicular to the surface formed by the display peripheral portion 11 a, the element length equal to or more than 1/400 wavelength including the open end of the antenna 20 is obtained. It can be seen that an improvement of 1 dB or more can be obtained if it is configured to be located inside the perforations 17.

  FIG. 9 shows that at least a part of the range of the element length from the open end of the antenna 20 is located inside the perforation 17 when the wireless device 1 is viewed from a direction substantially perpendicular to the surface formed by the display peripheral portion 11a ( In other words, it relates to how far the position of the perforation 17 can be offset from the open end toward the feeding point 19. The horizontal axis represents the length based on the wavelength (represented by the symbol λ). Is a diagram showing a simulation example for evaluating the antenna radiation pattern improvement level (expressed in dB on the vertical axis). Among the simulation conditions, the shape, size, and frequency of the antenna 20 are the same as those in FIG. The shape of the perforations 17 is a square.

  According to the simulation example shown in FIG. 9, when the wireless device 1 is viewed from a direction substantially perpendicular to the surface formed by the display peripheral portion 11a, at least one of the ranges from the open end of the antenna 20 to the 1/50 wavelength equivalent. It can be seen that an improvement of 1.5 dB or more can be obtained if the portion is configured to be located inside the perforation 17.

  In the above description, when the wireless device 1 is viewed from a direction substantially perpendicular to the surface formed by the display peripheral portion 11a, the open end of the antenna 20 or a portion in the vicinity thereof is positioned inside the perforation 17 provided in the display peripheral portion 11a. To do. Since the antenna 20 operates as a quarter-wavelength monopole antenna with an open end, the open end corresponds to a place where the maximum value of the voltage is distributed when the antenna 20 is fed. To express this point more generally, the portion near the portion where the maximum value of the voltage is distributed when the antenna is fed is provided in the housing when viewed from the direction that requires the required antenna directivity. The wireless device may be configured to be located inside the perforation.

  The portion where the maximum value of the voltage is distributed when the antenna is fed is not always an open end, for example, when the element length corresponds to an odd multiple of 3 or more of a quarter wavelength. Also, the antenna type need not be limited to the monopole type with an open tip.

  According to the embodiment of the present invention, when an antenna built in a housing having at least a part of a surface formed of metal is fed, a portion in the vicinity of a place where a maximum value of voltage is distributed Improve the antenna radiation pattern in the direction compared to the case where there is no perforation by configuring it so that it is located inside the perforation provided in the metal part when viewed from a direction substantially perpendicular to the surface made of metal Can do. Similarly, the antenna radiation pattern can be improved in other directions.

  In the description of the above embodiments, the shape, configuration, dimensions, connection, frequency value used for evaluation, direction of antenna directivity, etc. are examples, and the gist of the present invention is described. Various modifications are possible without departing from the scope.

The figure showing the main structures of the radio | wireless apparatus which concerns on the Example of this invention. The side view showing the positional relationship of the main structures contained in the housing | casing of the radio | wireless apparatus which concerns on the Example of this invention. The front view showing the positional relationship of the main structures contained in the housing | casing of the radio | wireless apparatus which concerns on the Example of this invention. The figure showing the antenna radiation pattern measurement example of the radio | wireless apparatus which concerns on the Example of this invention compared with the case where there is no perforation | boring in a housing | casing. The figure showing the example of a measurement of the impedance characteristic and VSWR characteristic of the antenna of the radio | wireless apparatus which concerns on the Example of this invention. The figure showing the example of a measurement of the impedance characteristic and VSWR characteristic of an antenna when there is no piercing | piercing in a housing | casing with respect to the radio | wireless apparatus which concerns on the Example of this invention. In the Example of this invention, the figure showing the example of a simulation which evaluates the relationship between the presence or absence or shape of a perforation, and the improvement level of an antenna radiation pattern. In an embodiment of the present invention, the antenna radiation pattern is improved depending on how far the element length range including the open end of the antenna is located inside the perforation when viewed from a direction substantially perpendicular to the surface formed by the display peripheral portion. The figure showing the example of a simulation which evaluates a level. In an embodiment of the present invention, the antenna radiation pattern depends on whether at least a part of the element length range from the open end of the antenna is located inside the perforation when viewed from a direction substantially perpendicular to the surface formed by the display peripheral portion. The figure showing the example of simulation which evaluates the improvement level of.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radio | wireless apparatus 11 1st housing | casing 11a Display surrounding part 12 2nd housing | casing 13 Connection part 14 Display part 15 1st board | substrate 16 2nd board | substrate 17 Perforation 19 Feeding place 20 Antenna

Claims (7)

A housing perforated in a portion of one surface formed with a conductive material;
In the vicinity of a portion that is incorporated in the housing, has a resonance frequency determined by size and is connected to a power feeding location provided in the housing, and where the maximum value of the voltage is distributed when power is fed at the resonance frequency And an antenna disposed so as to be positioned inside the perforation when viewed from a direction substantially perpendicular to one surface of the casing.   The antenna has a perforation when an element length equal to or greater than 1/400 wavelength of the resonance frequency including a portion where the maximum value of the voltage is distributed is viewed from a direction substantially perpendicular to one surface of the housing. The radio apparatus according to claim 1, wherein the radio apparatus is disposed so as to be located inside.   In the antenna, at least a part of a range from a location where the maximum value of the voltage is distributed to an element length corresponding to 1/50 wavelength of the resonance frequency is seen from a direction substantially perpendicular to the surface of the housing 1. The wireless device according to claim 1, wherein the wireless device is disposed so as to be located inside the perforation.   The radio apparatus according to claim 1, wherein the antenna has an open end corresponding to a location where the maximum value of the voltage is distributed.   The antenna has an open end corresponding to a place where the maximum value of the voltage is distributed, and an element length equal to or longer than 1/400 wavelength of the resonance frequency including the open end is equal to one surface of the casing. The wireless device according to claim 1, wherein the wireless device is disposed so as to be located inside the perforation when viewed from a direction substantially perpendicular to the perforation.   The antenna has an open end corresponding to a place where the maximum value of the voltage is distributed, and at least a part of a range from the open end to an element length corresponding to 1/50 wavelength of the resonance frequency is the housing. The radio apparatus according to claim 1, wherein the radio apparatus is disposed so as to be located inside the perforation when viewed from a direction substantially perpendicular to one surface of the body.   The wireless device according to claim 1, wherein a display unit is attached to one surface of the housing, and at least a portion of the housing surrounding the display unit is formed of the conductive material.

Images