JP2005072915A - Antenna assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a horizontally or vertically polarized mean beam tilted in the horizontal direction, using a small size flat structure easily mountable on a small size radiotelephone. <P>SOLUTION: Linear elements 101a-101d each having a length in a range of about 1/4 to about 3/8 of the wavelength of an operating frequency are disposed in a rhombic shape, and folded bypass elements 102a, 102b are connected to a set of opposite apexes. A feed point 103 is provided on one apex of the other set of opposite apexes and the linear elements are connected to the other apex. A reflection plate is disposed at a position with a distance h parallel from the layout plane of the linear elements 101a-101d. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an antenna device of a wireless LAN system, and is suitable for application to, for example, a fixed wireless device and a terminal wireless device.

  In high-speed wireless communication such as a wireless LAN system, there is a problem that transmission quality deteriorates due to multipath fading and shadowing, which is particularly noticeable indoors. For this reason, in order to avoid such deterioration in transmission quality, a directional antenna mounted on a wireless communication apparatus is required to have an antenna apparatus that can control the main beam to be directed in all directions. Sector antennas have been studied as one method. A sector antenna is one in which a plurality of antenna elements with main beams directed in different directions are arranged, and the plurality of antenna elements are selectively switched according to the radio wave propagation environment.

  Also, in general, antennas mounted on terminal radios for laptop computers used on desks and fixed radios installed on the ceiling may have a planar structure for reasons of the structure of those radios. It is required that the elevation angle of the main beam is tilted (tilted) from the vertical direction to the horizontal direction with respect to the antenna surface.

  As a sector antenna that realizes such radiation characteristics, a multi-sector antenna using a monopole Yagi / Uda array disclosed in Non-Patent Document 1 has been proposed (conventional example 1). FIG. 15 is a diagram illustrating a configuration of a multi-sector antenna according to Conventional Example 1. In the sector antenna shown in this figure, a plurality of monopole arrays 12 are arranged radially on a circular ground plane 11 around a cylindrical reflector. Metal fins 13 are arranged between the monopole arrays in order to suppress the coupling between the arrays. At this time, as a single characteristic of the monopole array, the main beam is formed in the direction in which the elevation angle θ of the vertical surface is 70 degrees, and the half-value angle of the conical surface is 30 degrees. By arranging such monopole arrays on a horizontal plane at intervals of 30 degrees and selectively feeding each monopole array, a 12-sector antenna that is divided into 360 degrees by 12 is realized. For example, when the operating frequency is 5 GHz, the sector antenna has a diameter of 586 mm (9.76 wavelength) and an area of 269703 square mm.

  In addition, a planar multi-sector antenna using the slot Yagi-Uda array disclosed in Non-Patent Document 2 has been proposed (Conventional Example 2). FIG. 16 is a diagram illustrating a configuration of a multi-sector antenna according to the second conventional example. The sector antenna shown in this figure has six slot arrays 22a to 22f arranged on a substrate 21 in a circular pattern in a radial pattern. Each of the six slot arrays 22a to 22f is composed of five element slots. At this time, as a single characteristic of the slot array, a main beam having an elevation angle θ of 60 degrees in the vertical plane is formed, and the half-value angle of the conical plane is about 56 degrees. By arranging such slot arrays at intervals of 60 degrees on a horizontal plane and selectively feeding each slot array, a 6-sector antenna obtained by dividing 360 degrees into 6 can be configured. For example, when the operating frequency is 5 GHz, the sector antenna has a diameter of 273 mm (4.55 wavelength) and an area of 58535 square mm.

Furthermore, a multi-beam antenna using a waveguide element shared patch Yagi-Uda array disclosed in Non-Patent Document 3 has been proposed (Conventional Example 3). FIG. 17 is a diagram illustrating a configuration of a multi-beam antenna according to Conventional Example 3. The multi-beam antenna shown in this figure is formed on the surface of a circular dielectric substrate 31, and rectangular patch waveguide elements 33 are arrayed radially around a regular hexagonal waveguide element 32. A power feeding element 34 is arranged outside. In this way, three rows of waveguide elements intersect each other at an angle of 60 degrees with the regular hexagonal waveguide elements 32 as the center, thereby constituting six rows of patch Yagi-Uda arrays. Here, when one power feeding element is fed, a waveguide element array including a regular hexagonal waveguide element operates as a Yagi-Uda array. At this time, the main beam is formed in a direction where the elevation angle θ of the vertical surface is 45 degrees, and the half-value angle of the conical surface is about 63 degrees. By selectively feeding the feeding elements in this way, a 6-sector antenna obtained by dividing 360 degrees into 6 can be configured. The dimensions of the sector antenna are, for example, when the operating frequency is 5 GHz, the diameter is 1.83 wavelengths (110 mm), and the area is 9503 square mm.
IEICE Transactions (B-II), Vol.J80-B-II, No.5, pp.424-433, May 1997. IEICE Transactions (B), Vol.J85-B, No.9, pp1633-1643, Sep. 2002. IEICE technical report, A / P2001-81, Oct. 2001.

  However, since the multi-sector antenna using the monopole Yagi / Uda array of the above-described conventional example 1 has a projection, it is mounted on a terminal radio or a fixed radio that is required to have a planar structure. In addition to being unsuitable as an antenna, there is a problem that productivity is low.

  In addition, the planar multi-sector antenna using the slot Yagi / Uda array of the above-described conventional example 2 operates each array antenna independently for each sector, and therefore requires as many array antennas as the number of sectors. There is a problem of growing. Further, since each array antenna is arranged radially, there is a problem that it becomes a circular shape and is difficult to be mounted on a small wireless device.

  In addition, the multi-beam antenna using the waveguide element shared patch Yagi / Uda array of the above-mentioned conventional example 3 has a circular shape because a rectangular patch has to be arranged radially around a regular hexagonal parasitic element, and is small in size. There is a problem that it is difficult to install in a radio.

  The present invention has been made in view of the above points, and provides an antenna device that forms a horizontally polarized or vertically polarized main beam tilted in the horizontal direction with a small planar structure that can be easily mounted on a small wireless device. For the purpose.

  In order to solve such a problem, the antenna device of the present invention has four lines each having a length of approximately ¼ wavelength to approximately 3/8 wavelength of the operating frequency and arranged in a rhombus shape on a plane. Connected to a linear element, a feeding means for feeding power to one end of the first linear element and one end of the second linear element, the other end of the first linear element and one end of the third linear element, A folded first linear detour element having a length of approximately ¼ wavelength, connected to the other end of the second linear element and one end of the fourth linear element, and has a total length of approximately ¼ wavelength. A folded second linear detour element having a length of: and a reflector disposed at a predetermined interval substantially parallel to a plane on which the linear element is disposed, and the third line The other end of the linear element and the other end of the fourth linear element are connected.

  According to this configuration, the first and second linear detour elements shift the current phase between the first and second linear elements and the third and fourth linear elements, thereby radiating radio waves and reflections. By synthesizing the radio waves reflected by the plates, a main beam having a horizontally polarized wave tilted in the horizontal direction can be formed, and a small and planar antenna device can be realized.

  The antenna device according to the present invention has four linear elements each having a length of approximately ¼ wavelength to approximately ／ wavelength of the used frequency and arranged in a rhombus shape on a plane, and a first line. A first feeding means for feeding power to one end of the linear element and one end of the second linear element; a second feeding means for feeding power to one end of the third linear element and one end of the fourth linear element; and the first linear shape. A folded first linear detour element having a length of approximately ¼ wavelength and connected to the other end of the element and the other end of the third linear element, and the other of the second linear element A folded second linear detour element having an overall length of approximately ¼ wavelength, connected to the end and the other end of the fourth linear element, and a plane on which the linear element is disposed. And a reflector arranged at a predetermined interval in parallel.

  According to this configuration, by selectively switching the power supply from the first power supply means and the second power supply means, it is possible to form a main beam having a horizontally polarized wave that is tilted in the horizontal direction. A two-directional multi-beam antenna with a structure can be realized.

The antenna device according to the present invention includes a dielectric substrate having a predetermined dielectric constant, a conductor layer formed on the surface of the dielectric substrate, and a length of approximately ¼ wavelength to approximately ／ wavelength of the use frequency. Four slot elements formed in a rhombus shape in the conductor layer, and a first feeding means for feeding power at a position where one end of the first slot element and one end of the second slot element are connected, A folded first slot bypass element connected to the other end of the first slot element and one end of the third slot element and having a total length of approximately ¼ wavelength; the other end of the second slot element; A folded second slot bypass element connected to one end of the fourth slot element and having a total length of approximately ¼ wavelength, and disposed at a position substantially parallel to the conductor layer and spaced apart from the conductor layer. A reflector,
And the other end of the third slot element and the other end of the fourth slot element are connected.

  According to this configuration, the first and second slot detour elements shift the current phases of the first and second slot elements and the third and fourth slot elements, and the radio waves radiated thereby are reflected by the reflector. By combining the generated radio waves, a main beam having a vertically polarized wave tilted in the horizontal direction can be formed, and a small and planar antenna device can be realized.

  In the antenna device of the present invention, in the above configuration, the second feeding unit that feeds power at a position where the other end of the third slot element and the other end of the fourth slot element are connected, and the first and second feedings. And a switching unit that selectively switches power supply from the unit.

  According to this configuration, the switching unit can selectively switch the power supply from the first power supply unit and the second power supply unit, thereby forming a main beam having a horizontally polarized wave that is tilted in the horizontal direction. A small and planar multi-beam antenna having a planar structure can be realized.

  The antenna device according to the present invention employs a configuration in which, in the above configuration, a microstrip line provided on the back surface of the substrate on which the conductor layer of the dielectric substrate is formed is used as the feeding unit.

  According to this configuration, impedance matching can be achieved by adjusting the length of the microstrip line, facilitating power feeding, and miniaturization of the antenna device and improvement in productivity.

  The antenna device of the present invention has a configuration in which, in the above configuration, the microstrip line includes switching means for switching between short-circuiting and feeding at a position that is an odd multiple of a quarter wavelength from the coupling portion with the slot element. take.

  According to this configuration, an antenna device having a high directivity gain and a good F / B ratio can be realized.

  The antenna device of the present invention has a configuration in which, in the above configuration, the microstrip line includes switching means for switching between opening and feeding at a position that is approximately an integral multiple of a half wavelength from the coupling portion with the slot element. take.

  According to this configuration, an antenna device having a high directivity gain and a good F / B ratio can be realized.

  In the antenna device of the present invention, in the above configuration, the inner conductor layer and the outer conductor layer surrounded by the diamond-shaped slot elements are each formed in a copper foil pattern in the approximate center of the four slot elements. The structure connected by the formed connection conductor is taken.

  According to this configuration, it is possible to realize an antenna device that can easily achieve impedance matching and has a good F / B ratio.

  The antenna device of the present invention employs a configuration in which a plurality of the antenna devices described above are used, and the plurality of antenna devices are respectively rotated on a plane by equal angles.

  According to this configuration, it is possible to realize a sector antenna that forms a main beam in a desired direction by selectively feeding power to a plurality of antenna devices.

  The antenna device of the present invention employs a configuration in which the three antenna devices described in any of the above are arranged in a line on a straight line, and the three antenna devices are respectively rotated by 60 degrees.

  According to this configuration, a small 6-sector antenna is realized with a planar structure suitable for mounting on a small wireless device by rotating and arranging antenna devices that form main beams in directions different by 180 degrees by 60 degrees. can do.

  As described above, according to the present invention, linear elements or slot elements each having a length in the range of approximately ¼ wavelength to approximately ／ wavelength of the operating frequency are arranged in a rhombus shape and face each other. By connecting each of the folded detour elements to a pair of vertices, and further arranging a reflector at a position spaced in parallel with the arrangement surface of the linear element or slot element, in the horizontal direction A tilted horizontally or vertically polarized main beam can be formed.

  In addition, by arranging a plurality of rhombus-shaped linear elements or slot elements connected to the detour element by rotating them at equal angles on the plane, a small sector with a planar structure suitable for mounting on a small radio device. An antenna can be realized.

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

(Embodiment 1)
FIG. 1 is a diagram illustrating a configuration of an antenna device according to Embodiment 1 of the present invention. Hereinafter, the operation frequency of the antenna will be described as 5 GHz. For convenience of explanation, coordinate axes as shown in the figure are defined.

  Fig.1 (a) is a top view which shows the structure of the antenna apparatus which concerns on Embodiment 1 of this invention. In this figure, linear elements 101a to 101d are conductors having an element length L1 of about 1/3 wavelength (20 mm) and an element width of 1 mm, for example. These linear elements 101a to 101d are arranged in a square shape as shown in FIG.

  The linear detour elements 102a and 102b are folded conductors having an overall length of about 1/4 wavelength (15 mm), a length L2 of about 1/8 wavelength (7.5 mm), and an element width of, for example, 1 mm. . The linear bypass element 102a is connected between the linear element 101a and the linear element 101c, and the linear bypass element 102b is connected between the linear element 101b and the linear element 101d. Here, by the coupling between the linear detour element 102a and the linear detour element 102b, the coupling between the linear detour element 102a and the linear elements 101a and 101c, or the coupling between the linear detour element 102b and the linear elements 101b and 101d. In order to minimize degradation of the radiation characteristics, the linear detour elements 102a and 102b are connected so as to protrude outward from the square shape.

  The power supply unit 103 is provided between the linear element 101a and the linear element 101b and supplies power to the linear element. The linear element 101c and the linear element 101d are connected.

  The linear elements 101a to 101d, the linear detour elements 102a and 102b, and the power feeding unit 103 configured as described above constitute a linear antenna element.

  FIG.1 (b) is an arrow line view which shows the structure of the antenna apparatus which concerns on Embodiment 1 of this invention, and is the figure seen from the arrow direction of Fig.1 (a), ie, -Y side. In this figure, the reflector 104 is a conductor plate disposed at a position where the distance h is 0.42 wavelength (25 mm) away from the surface (XY plane) on which the linear antenna element is disposed on the −Z side.

  Next, the operation of the antenna device having the above-described configuration will be described with reference to the drawings. 2A and 2B are diagrams showing a current distribution on the linear elements 101a to 101d of the antenna device according to Embodiment 1 of the present invention. FIG. 2A is a current amplitude characteristic, and FIG. 2B is a current phase. The characteristics are shown. Note that the symbols (A) to (D) shown on the horizontal axis in FIG. 2 correspond to the positions of the symbols (A) to (D) shown in FIG.

  In FIG. 2A, a current amplitude characteristic 201a indicates a current amplitude characteristic of the linear element 101a and the linear element 101b, and the current amplitude takes a peak value at the connection portion between the linear element 101a and the linear element 101b. I can confirm that. Similarly, the current amplitude characteristic 201b indicates the current amplitude characteristic of the linear element 101c and the linear element 101d, and it can be confirmed that the current amplitude has a peak value at the connection portion between the linear element 101c and the linear element 101d. .

  In FIG. 2B, the current phase characteristic 202a indicates the current phase characteristic of the Y direction component of the linear element 101a and the linear element 101b, and the current phase characteristic 202b is linear with the linear element 101c. The current phase characteristic of the Y direction component of the element 101d is shown. 2A and 2B, it can be confirmed that the current phase difference of the Y-direction component between the peak points of the current amplitude is about 150 degrees. This current phase difference is the length of the distance between the peak points plus the linear element 101a, the linear detour element 102a, and the linear element 101c (or the linear element 101b, the linear detour element 102b, and the linear element. This is because the current phase of the Y direction component is inverted by 180 degrees between the peak points.

  Here, when the linear elements 101a and 101b are regarded as a pair of antenna elements, it is considered that the operation is close to a half-wave dipole having a Y-direction polarization because a peak point of current exists at the center of the element. Similarly, when the linear elements 101c and 101d are regarded as a pair of antenna elements, it is considered that the operation is close to a half-wave dipole having a Y-direction polarization. Further, in FIG. 2B, since the phase difference between these antenna elements is 150 degrees, the antenna apparatus shown in FIG. 1 has a half-wave dipole array in which two elements are arranged in the X direction with a phase difference of 150 degrees. It can be considered that the operation is almost the same as when power is supplied.

  Next, the operation of the antenna device will be described focusing on the vertical (XZ) plane. Focusing on the vertical (XZ) plane, the directivity of the half-wave dipole of the Y-direction polarization is isotropic, and can be modeled with a point wave source.

  FIG. 3 is a schematic diagram showing the operation of the antenna device according to the first embodiment of the present invention using a point wave source model. Specifically, it is a diagram in which a two-element half-wave dipole array is modeled as a two-element point wave source focusing on the vertical (XZ) plane. The point wave source 301a is a model of the linear element 101a and the linear element 101b, and the point wave source 301b is a model of the linear element 101c and the linear element 101d. Here, from FIG. 2B, the excitation phase of the point wave source 301a advances by 150 degrees with respect to the excitation phase of the point wave source 301b.

  Further, when the effect of the reflector 104 is modeled using the principle of mapping, the image wave sources 302a and 302b are respectively located at positions 2h (0.84 wavelength (50 mm)) away from the point wave sources 301a and 301b on the -Z side. Can be assumed. At this time, the excitation phases of the image wave sources 302a and 302b are inverted by 180 degrees with respect to the excitation phases of the point wave sources 301a and 301b, respectively.

  Since the position of the point wave sources 301a and 301b in the X direction is the peak point of the current amplitude on the linear element, the distance L3 between the point wave sources 301a and 301b is about ½ wavelength (30 mm).

  Radiation by the four-element array of the point wave sources 301a and 301b and the image wave sources 302a and 302b configured as described above forms main beams 303a and 303b in a direction tilted by a tilt angle α (55 degrees) from the ± Z direction. Will be. However, since the reflector 104 actually exists, only the direction of the main beam 303a is obtained.

  FIG. 4 is a diagram showing the directivity of the antenna device according to Embodiment 1 of the present invention. 4A shows the directivity of the vertical (XZ) plane, and FIG. 4B shows the directivity of the conical surface when the elevation angle θ is 55 degrees.

  In FIG. 4A, directivity 401 indicates the directivity of the horizontally polarized wave (Eφ) component, and it can be confirmed that a main beam tilted in the direction where the elevation angle θ is 55 degrees can be obtained.

  In FIG. 4B, the directivity 402 indicates the directivity of the horizontally polarized wave (Eφ) component similarly to the directivity 401, and it can be confirmed that the main beam is directed in the + X direction. At this time, the directivity gain of the main beam is 10.5 dBi, the half-value angle of the conical surface is 57 degrees, and the F / B ratio (ratio between the main beam and the back lobe) is 7 dB.

  Next, the case where the linear detour element is connected to the inner side of the square shape will be described with reference to FIG. Fig.5 (a) is a top view which shows the structure of the antenna apparatus at the time of connecting a linear detour element inside a square. FIG. 5B is an arrow view showing the configuration of the antenna device when the linear detour element is connected to the inside of the square, and is viewed from the arrow direction in FIG. 5A, that is, from the −Y side. It is a figure. However, in these drawings, the same reference numerals as those in FIG.

  In FIG. 5A, linear detour elements 501a and 501b are conductors having a total length of about 1/4 wavelength (15 mm) and an element width of, for example, 1 mm, and a length L4 of about 1/8 wavelength (7. 5mm). The linear bypass element 501a is connected between the linear element 101a and the linear element 101c, and the linear bypass element 501b is connected between the linear element 101b and the linear element 101d.

  FIG. 6 is a diagram illustrating the directivity of the antenna device when the linear detour element is connected to the inside of the square. 6A shows the directivity of the vertical (XZ) plane, and FIG. 6B shows the directivity of the conical surface when the elevation angle θ is 50 degrees.

  In FIG. 6A, the directivity 601 indicates the directivity of the horizontal polarization (Eφ) component, and it can be confirmed that a main beam tilted in the direction of the elevation angle θ of 50 degrees can be obtained.

  In FIG. 6B, the directivity 602 indicates the directivity of the horizontal polarization (Eφ) component similarly to the directivity 601, and it can be confirmed that the main beam is directed in the + X direction. At this time, the directivity gain of the main beam is 9.6 dBi, the half-value angle of the conical surface is 57 degrees, and the F / B ratio is 5.5 dB.

  In this way, by connecting the linear detour element to the inner side of the square formed by the linear elements, compared to the case where the linear detour element is protruded to the outer side of the square and connected, The size can be reduced by about 35%. However, the gain is reduced by about 1 dB due to the coupling between the linear detour elements and the linear detour elements, and the coupling between the linear detour elements, and the F / B ratio is degraded by 1.5 dB. For this reason, it is desirable to determine the connection direction of the linear detour element according to the application.

  As described above, according to the present embodiment, a linear detour element having a folded shape is provided at a pair of vertices of a square and a linear element formed in a square shape. By disposing the reflectors at a distance, it is possible to realize a small and planar antenna device suitable for mounting on a small wireless device, and to produce a horizontally polarized wave with a vertical tilt angle of 55 degrees. The main beam can be formed. Further, by arranging the linear detour element inside the square shape, a smaller antenna device can be realized.

(Embodiment 2)
Fig.7 (a) is a top view which shows the structure of the antenna apparatus which concerns on Embodiment 2 of this invention. Moreover, FIG.7 (b) is an arrow line view which shows the structure of the antenna apparatus which concerns on Embodiment 2 of this invention, and is the figure seen from the arrow direction of Fig.7 (a), ie, -Y side. . However, in these drawings, the same reference numerals as those in FIG. 1 are attached to the portions common to those in FIG. 1, and the detailed description thereof is omitted. Hereinafter, the operation frequency of the antenna will be described as 5 GHz. For convenience of explanation, coordinate axes as shown in the figure are defined.

  The power supply unit 701 is provided between the linear element 101c and the linear element 101d, and supplies power to the linear element.

  In the antenna device having such a configuration, when the linear antenna element is excited from the power feeding unit 103, the power feeding unit 701 is short-circuited and operates so that the linear element 101c and the linear element 101d are connected. Further, when the linear antenna element is excited from the power supply unit 701, the power supply unit 103 is short-circuited and operates so that the linear element 101a and the linear element 101b are connected. By operating in this way, the main beam can be switched in two directions with one antenna element.

  FIG. 8 is a diagram showing the directivity of the antenna device according to Embodiment 2 of the present invention. 8A shows the directivity of the vertical (XZ) plane, and FIG. 8B shows the directivity of the conical surface when the elevation angle θ is 55 degrees.

  In FIG. 8A, the directivity 801a indicated by a solid line indicates the directivity of the horizontally polarized wave (Eφ) component when the linear antenna element is excited from the power supply unit 103 and the power supply unit 701 is short-circuited. At this time, it can be confirmed that a main beam tilted in a direction in which the elevation angle θ is 55 degrees can be obtained. A directivity 801b indicated by a dotted line indicates the directivity of the horizontal polarization (Eφ) component when the linear antenna element is excited from the power supply unit 701 and the power supply unit 103 is short-circuited. At this time, it can be confirmed that a main beam tilted in a direction in which the elevation angle θ is 55 degrees can be obtained.

  In FIG. 8B, the directivity 802a indicated by the solid line is the horizontal deviation when the linear antenna element is excited from the feed point 103 and the feed portion 701 is short-circuited, as in the directivity 801a of FIG. The directivity of the wave (Eφ) component is shown, and it can be confirmed that the main beam is directed in the + X direction. In addition, the directivity 802b indicated by a dotted line is a horizontal polarization (Eφ) component when the linear antenna element is excited from the feeding point 701 and the feeding unit 103 is short-circuited, similarly to the directivity 801b of FIG. It can be confirmed that the main beam is directed in the -X direction. At this time, in both the directivity 802a and 802b, the directivity gain of the main beam is 10.5 dBi, and the half-value angle of the conical surface is 57 degrees.

  As described above, according to the present embodiment, the linear element formed in a square shape and the linear detour element having a folded shape are provided at a set of opposing vertices of the square, and the power feeding unit is provided at each of the other set of vertices. The reflector is arranged at a predetermined distance from the square-shaped linear element, the antenna device is excited from one of the feeding units, and the other feeding unit is operated so as to be in a short-circuited state. By switching the operation of the unit, a main beam can be formed in two directions, and a multi-beam antenna having a small planar structure can be realized.

(Embodiment 3)
FIG. 9 is a plan view showing the configuration of the antenna device according to Embodiment 3 of the present invention. In FIG. 9, the upper part of the drawing is a plan view seen from the + Z side, and the lower part of the drawing is a plan view seen from the −Y side. However, in these drawings, the same reference numerals as those in FIG. 1 are attached to the portions common to those in FIG. 1, and the detailed description thereof is omitted. Hereinafter, the operation frequency of the antenna will be described as 5 GHz. For convenience of explanation, coordinate axes as shown in the figure are defined.

  In FIG. 9, a substrate 901 is a dielectric having a relative dielectric constant εr of, for example, 2.6 and a thickness of 1.6 mm, and the dimension L5 × L6 is 0.67 wavelength × 0.77 wavelength (40 mm × 46 mm). ).

  The copper foil layer 902 is a copper foil bonded to the Z side surface of the substrate 901. The slot elements 903a to 903d are voids (copper foil pattern) formed by scraping the copper foil layer 902, the element length L7 is about 1 / 3λe (16.6 mm), and the element width is, for example, 1 mm. Here, λe is an effective wavelength of the slot element on the substrate 901, and is about 83% of the wavelength (λ0) in free space. That is, λe = 0.83λ0. These slot elements 903a to 903d are arranged in a square shape as shown in FIG.

  The connection conductors 904a to 904d are formed in the slot elements 903a to 903d in a square shape, for example, with a copper foil pattern, and the slot elements 903a to 903d are separated from each other at approximately the center of the slot elements 903a to 903d. The copper foil layer and the outer copper foil layer are connected. As described above, by dividing the slot elements 903a to 903d by the connection conductors 904a to 904d, impedance matching can be easily achieved and an antenna apparatus having a good F / B ratio can be realized.

  The slot detour elements 905a and 905b are voids formed by scraping the copper foil layer 902, and have a total length of about 1 / 4λe (12.5 mm) and a length L8 of about 1 / 8λe (6.25 mm). It is folded and formed. The element width is 1 mm, for example. The slot bypass element 905a is connected between the slot element 903a and the slot element 903c, and the slot bypass element 905b is connected between the slot element 903b and the slot element 903d. Here, the slot detour element circuits 905a and 905b are connected so as to protrude outward from the square shape. The slot element 903a and the slot element 903b, and the slot element 903c and the slot element 903d are connected to each other.

  The slot elements 903a to 903d, the connecting conductors 904a to 904d, and the slot detour elements 905a and 905b configured as described above constitute a slot antenna element.

  The microstrip line 906 is formed by a copper foil pattern along the X direction on the −Z side surface of the substrate 901 so as to pass through the connection portion between the slot element 903a and the slot element 903b. The width W1 of the microstrip line 906 is set to 4.6 mm so that the characteristic impedance is 50Ω. Further, a distance L9 between the tip of the microstrip line 906 and the connecting portion between the slot element 903a and the slot element 903b is set to 1.5 mm, for example.

  With the above configuration, since the microstrip line 906 and the slot antenna element are electromagnetically coupled, a signal from the power feeding unit 907 can be supplied to the slot antenna element via the microstrip line 906. . Further, impedance matching can be performed by setting the distance L9 to an appropriate length. In this way, power supply from the microstrip line, which is a planar circuit, is facilitated, and the antenna device can be reduced in size and productivity can be improved.

  Here, the antenna device of the present embodiment shown in FIG. 9 can be considered to be almost equivalent to the antenna device shown in FIG. 1 in which the linear elements are replaced with slot elements. It can be replaced and explained. Therefore, the main polarization component of the antenna apparatus shown in FIG. 1 is a horizontal (Eφ) component, whereas the main polarization component of the antenna apparatus shown in FIG. 9 is a vertical (Eθ) component.

  FIG. 10 is a diagram showing the directivity of the antenna device according to Embodiment 3 of the present invention. 10A shows the directivity of the vertical (XZ) plane, and FIG. 10B shows the directivity of the conical surface when the elevation angle θ is 45 degrees.

  In FIG. 10A, directivity 1001 indicates the directivity of the vertically polarized wave (Eθ) component, and it can be confirmed that a main beam tilted in the direction where the elevation angle θ is 45 degrees can be obtained.

  In FIG. 10B, the directivity 1002 indicates the directivity of the vertically polarized wave (Eθ) component similarly to the directivity 1001, and it can be confirmed that the main beam is directed in the + X direction. At this time, the directivity gain of the main beam is 9.8 dBi, the half-value angle of the conical surface is 62 degrees, and the F / B ratio is 10 dB.

  As described above, according to the present embodiment, the slot element formed in a square shape on the surface of the dielectric substrate and the slot bypass element are provided at a pair of vertices facing the square, and the microstrip line is provided on the back surface of the dielectric substrate. Further, by arranging the reflector at a predetermined distance from the slot element surface, it is possible to realize a small and planar antenna device suitable for mounting on a small wireless device, and The main beam having a tilt angle of 45 degrees can be formed, and the main polarization can be set to the vertical polarization (Eθ). In addition, power supply from the microstrip line, which is a planar circuit, is facilitated, and impedance matching is possible only by changing the microstrip line length.

  In the present embodiment, the slot element is formed by a copper foil pattern on a dielectric substrate. However, for example, the same effect can be obtained by forming a slot element by providing a gap in a conductor plate.

  Further, in the present embodiment, the connection conductor is formed in the slot element in a copper foil pattern, and the inner copper foil layer and the outer copper foil layer of the slot element are connected so as to be divided at substantially the center of the slot element. As described above, the same effect can be obtained by forming the connecting conductor on the same plane as the microstrip line and connecting the square inner copper foil layer and the outer copper foil layer through the through holes.

(Embodiment 4)
FIG. 11 is a plan view showing the configuration of the antenna device according to Embodiment 4 of the present invention. 11A is a plan view seen from the + Z side and a plan view seen from the −Y side, and FIG. 11B is a plan view seen from the −Z side excluding the reflector 104. is there. However, in FIG. 11A and FIG. 11B, the same reference numerals as those in FIG. Hereinafter, the operation frequency of the antenna will be described as 5 GHz. For convenience of explanation, coordinate axes as shown in the figure are defined.

  The switch 1101 is a DPDT (Double Pole Double Throw) switch having two input terminals 1102a and 1102b and two output terminals 1102c and 1102d. The switch 1101 has an input terminal 1102b and an output terminal 1102d connected when the input terminal 1102a is connected to the output terminal 1102c, and an input terminal 1102b and an output terminal 1102c when the input terminal 1102a is connected to the output terminal 1102d. Works to be connected.

  The power supply unit 1104 is connected to the input terminal 1102a via the copper foil pattern 1103, the input terminal 1102b is connected to the copper foil pattern 1105, and is grounded to the copper foil layer 902 which is a ground conductor via the through hole 1106. . Further, a microstrip line 1107a is connected to the output terminal 1102c, and a microstrip line 1107b is connected to the output terminal 1102d. Copper foil patterns 1103 and 1105 are copper foil patterns formed on the −Z side surface of the substrate 901.

  The microstrip line 1107a is formed by a copper foil pattern on the −Z side surface of the substrate 901, one end is disposed so as to pass through the connection portion between the slot element 903a and the slot element 903b, and the other end is connected to the output terminal 1102c of the switch 1101. It is connected. Similarly, the microstrip line 1107b is also formed by a copper foil pattern on the −Z side surface of the substrate 901, and one end is disposed so as to pass through the connection between the slot element 903c and the slot element 903d, and the other end is the output of the switch 1101. It is connected to the terminal 1102d.

  The width W2 of the microstrip lines 1107a and 1107b is set to 4.6 mm so that the characteristic impedance is 50Ω. Also, the distance L10 between the tip of the microstrip line 1107a and the connecting portion between the slot element 903a and the slot element 903b and the distance L10 between the tip of the microstrip line 1107b and the connecting portion between the slot element 903c and the slot element 903d are 1.5 mm. Is set.

  Next, the operation in the case of exciting the antenna device from the microstrip line 1107a in the antenna device having the above-described configuration will be described. A signal excited from the power feeding unit 1104 is input to the input terminal 1102 a of the switch 1101. At this time, the switch 1101 operates so that the input terminal 1102a and the output terminal 1102c are connected, and the input terminal 1102b and the output terminal 1102d are connected. Therefore, the signal input to the input terminal 1102a is input to the microstrip line 1107a via the output terminal 1102c.

  The microstrip line 1107b is grounded via the output terminal 1102d and the input terminal 1102b. Here, since the antenna element is constituted by a slot element, it can be considered to replace the electric field and magnetic field in the case of a linear element. Therefore, at the position of the coupling portion between the microstrip line 1107b and the slot element, Must be grounded. For this reason, the length from the coupling portion of the microstrip line 1107b and the slot element to the ground point, that is, the electrical length of the entire microstrip line 1107b, the copper foil pattern 1105, the through hole 1106, and the switch 1101 is 1 /. Must be set to an odd multiple of 4 wavelengths. Thereby, the directivity gain is high and the F / B ratio can be improved. Note that the operation of the antenna device excited from the microstrip line 1107a is the same as the operation described in Embodiment 3, and thus the description thereof is omitted here.

  Similarly, when the antenna device is excited from the microstrip line 1107b, the switch 1101 operates so that the input terminal 1102a and the output terminal 1102d, and the input terminal 1102b and the output terminal 1102c are connected to each other. At this time, since it is necessary to open at the position of the coupling portion between the microstrip line 1107a and the slot element, the length from the coupling portion between the microstrip line 1107a and the slot element to the grounding point is set to 1/4 wavelength Must be set to an odd multiple.

  FIG. 12 is a diagram showing the directivity of the antenna device according to Embodiment 4 of the present invention. 12A shows the directivity of the vertical (XZ) plane, and FIG. 12B shows the directivity of the conical surface when the elevation angle θ is 45 degrees.

  In FIG. 12A, directivity 1201a indicates the directivity of the vertically polarized wave (Eθ) component when the slot antenna element is excited from the microstrip line 1107a, and the main angle tilted in the direction where the elevation angle θ is 45 degrees. It can be confirmed that a beam is obtained. The directivity 1201b indicates the directivity of the vertically polarized wave (Eθ) component when the slot antenna element is excited from the microstrip line 1107b, and a main beam tilted in the direction where the elevation angle θ is 45 degrees can be obtained. Can be confirmed.

  In FIG. 12B, the directivity 1202a indicates the directivity of the vertical polarization (Eθ) component when the slot antenna element is excited from the microstrip line 1107a, similarly to the directivity 1201a in FIG. It can be confirmed that the main beam is directed in the + X direction. Similarly to the directivity 1201b in FIG. 12A, the directivity 1202b indicates the directivity of the vertical polarization (Eθ) component when the slot antenna element is excited from the microstrip line 1107b. It can be confirmed that is oriented in the -X direction. At this time, in both the directivity 1202a and 1202b, the directivity gain of the main beam is 9.8 dBi, and the half-value angle of the conical surface is 62 degrees.

  As described above, according to the present embodiment, the slot element formed in a square shape on the surface of the dielectric substrate and the slot detour element are provided at a pair of opposing vertices of the square, and the dielectric is formed at the other pair of vertices. A microstrip line is disposed on the back surface of the substrate, a reflector is disposed at a predetermined distance from the slot element surface, a slot antenna element is excited from one microstrip line, and the other microstrip line and slot element are The main beam is formed in two directions by switching operation so that the position of the coupling portion of the antenna is in an open state, the main polarization component is vertical polarization, and a small and planar multi-beam antenna is formed. Can be realized.

  In the present embodiment, the description has been made using one DPDT switch as the switch. However, for example, a plurality of switches may be used so as to be configured using three single pole double throws (SPDT).

  In the present embodiment, one terminal of the switch is grounded, and the length from the coupling portion between the microstrip line and the slot element to the ground point is described as an odd multiple of 1/4 wavelength. One terminal is opened, and the length from the coupling portion between the microstrip line and the slot element to the ground point is opened at the position of the coupling portion between the microstrip line and the slot element so as to be an integral multiple of ½ wavelength. Even in such a configuration, the directivity gain is high and the F / B ratio can be improved.

(Embodiment 5)
FIG. 13 is a diagram showing a configuration of an antenna apparatus according to Embodiment 5 of the present invention. In FIG. 13, FIG. 13A is a plan view seen from the + Z side, and FIG. 13B is a plan view seen from the −Z side excluding the reflector. The antenna device shown in FIG. 13 is configured as a sector antenna by arranging three slot antenna elements shown in FIG. 11 on a straight line. For convenience of explanation, coordinate axes as shown in the figure are defined.

  In FIG. 13, slot antenna elements 1301a to 1301c have the same configuration as the antenna device shown in FIG. The slot antenna elements 1301a to 1301c are arranged on a straight line by rotating the main beam directions 1302a to 1302f by 60 degrees so that 360 degrees are divided into six in the horizontal (XY) plane.

  The slot antenna element 1301a is supplied with power from the microstrip lines 1303a and 1303b, and is switched to the main beam direction 1302a or 1302b by the switch 1304a. Similarly, the slot antenna element 1301b is fed from the microstrip lines 1303c and 1303d, and is switched to the main beam direction 1302c or 1302d by the switch 1304b. Further, the slot antenna element 1301c is fed from the microstrip lines 1303e and 1303f, and is switched to the main beam direction 1302e or 1302f by the switch 1304c. Since the operation of each of these slot antenna elements is the same as that described in the fourth embodiment, description thereof is omitted here.

  The switch 1305 is an SP3T (Single Pole 3 Throw) switch composed of one input terminal and three output terminals. The input terminal of the switch 1305 is connected to the power feeding unit 1306 via the microstrip line 1307, and the three output terminals are connected to the input terminals of the switches 1304a to 1304c via the microstrip lines 1308a to 1308c, respectively.

  As described above, by selectively feeding the slot antenna elements 1301a to 1301c using the switches 1304a to 1304c and 1305, a six-sector antenna obtained by dividing 360 degrees on the horizontal (XY) plane into six parts can be realized.

  The external dimensions of the 6-sector antenna configured as described above are such that when the operating frequency of the antenna is 5 GHz, L11 is 0.67 wavelength (40 mm), L12 is 1.57 wavelength (94 mm), and the area is 3760. Square mm. This area is about 2/5 of the area of the conventional 6-sector antenna shown in FIG. 17, and is greatly reduced in size.

  In addition, when the operating frequency of the antenna is 25 GHz, the external dimensions of the 6-sector antenna are 8.0 mm × 18.8 mm rectangular shape, for example, a shape and size suitable as an antenna mounted on a small wireless device for a notebook personal computer. It becomes.

  Next, the directivity of the sector antenna shown in FIG. 13 is shown. FIG. 14 is a diagram showing the directivity of the antenna apparatus according to Embodiment 5 of the present invention. FIGS. 14A to 14C show the directivity 1401a to 1401f of the vertically polarized wave (Eθ) component in the conical surface having an elevation angle θ of 45 degrees which is the main beam direction of the slot antenna elements 1301a to 1301c, respectively. .

  As can be seen from FIG. 15, it can be confirmed that the main beam is directed in different directions by 60 degrees on the horizontal (XY) plane. In this case, the directivity gain of the main beam is 9.8 dBi, and the half-value angle of the conical surface is 62 degrees. For this reason, a gain of about −3 dB from the maximum gain can be obtained even at an intermediate point between adjacent directivities where the gain is lowest.

  As described above, according to this embodiment, three slot antenna elements are rotated and arranged 60 degrees on a straight line, and each slot antenna element is selectively fed by a plurality of switches. A sector antenna can be realized.

  In this embodiment, the slot element is described, but a linear element may be used.

  In the present embodiment, the case where a 6-sector antenna is realized has been described. However, the present invention is not limited to this, and can also be applied to a case where a plurality of sector antennas are realized.

  In the present embodiment, it has been described that the slot antenna element is selectively fed using four switches. However, the configuration of the switch is not limited to this.

  In each of the above-described embodiments, the distance h from the linear element to the reflecting plate has been described as 0.42 wavelength. However, the vertical plane tilt angle α can be changed by changing the distance h. When the distance h is reduced, the vertical plane tilt angle tends to decrease, and when the distance h is increased, the vertical plane tilt angle tends to increase. However, as the distance h is increased, a back lobe is generated in the direction opposite to the main beam direction in the −X direction. Therefore, the distance h corresponding to the application is changed from a 1/4 wavelength to a 1/2 wavelength. It is desirable to choose appropriately. In this embodiment, the distance h is 0.42 wavelength, which is a value that optimizes the vertical plane tilt angle and the F / B ratio.

  In each of the above-described embodiments, the length of the linear element is described as 1/3 wavelength. However, the vertical plane tilt angle α can be changed by changing the length of the linear element. For this reason, it is desirable to appropriately select the length of the linear element in the range of ¼ wavelength to ３ wavelength according to the application. In this embodiment, the length of the linear element is 1/3 wavelength, which is a value that optimizes the vertical plane tilt angle and the F / B ratio.

  In each of the above-described embodiments, the length of the linear detour element is described as ¼ wavelength. However, the vertical plane tilt angle α can be changed by changing the length of the linear detour element. . For this reason, it is desirable to appropriately select the length of the linear detour element in the range of 0.2 wavelength to 0.35 wavelength according to the application. In the present embodiment, the length of the linear detour element is ¼ wavelength, which is a value that optimizes the vertical plane tilt angle and the F / B ratio.

  In each of the above-described embodiments, the linear elements are arranged in a square shape. However, the half-value angles of the vertical surface and the conical surface can be obtained by arranging the linear elements in a rhombus shape and changing the angle between the linear elements. Can be changed.

  The antenna device according to the present invention forms a horizontally polarized or vertically polarized main beam tilted in the horizontal direction, and realizes a small sector antenna having a planar structure suitable for mounting on a small radio. And can be applied to small wireless devices such as fixed wireless devices and terminal wireless devices.

(A) The top view which shows the structure of the antenna device which concerns on Embodiment 1 of this invention, (b) The arrow view which shows the structure of the antenna device which concerns on Embodiment 1 of this invention (A) The figure which shows the current amplitude characteristic on the linear element of the antenna apparatus which concerns on Embodiment 1 of this invention, (b) Current phase characteristic on the linear element of the antenna apparatus which concerns on Embodiment 1 of this invention Figure showing The schematic diagram which shows the operation | movement of the antenna apparatus which concerns on Embodiment 1 of this invention with a point wave source model (A) The figure which shows the directivity of the perpendicular | vertical surface of the antenna apparatus which concerns on Embodiment 1 of this invention, (b) The directivity of the conical surface in case the elevation angle (theta) of the antenna apparatus which concerns on Embodiment 1 of this invention is 55 degree | times. Figure showing (A) The top view which shows the structure of the antenna apparatus when a linear detour element is connected inside a square, (b) The arrow view which shows the structure of the antenna apparatus when a linear detour element is connected inside a square (A) The figure which shows the directivity of the vertical surface of an antenna apparatus when a linear detour element is connected inside a square, (b) The elevation angle θ of the antenna apparatus when a linear detour element is connected inside a square is The figure which shows the directivity of the conical surface of 50 degrees (A) The top view which shows the structure of the antenna device which concerns on Embodiment 2 of this invention, (b) The arrow view which shows the structure of the antenna device which concerns on Embodiment 2 of this invention (A) The figure which shows the directivity of the perpendicular | vertical surface of the antenna apparatus which concerns on Embodiment 2 of this invention, (b) The directivity of the conical surface in case the elevation angle (theta) of the antenna apparatus which concerns on Embodiment 2 of this invention is 55 degree | times. Figure showing Plan view showing the configuration of the antenna device according to Embodiment 3 of the present invention (A) The figure which shows the directivity of the perpendicular | vertical surface of the antenna apparatus which concerns on Embodiment 3 of this invention, (b) The directivity of the conical surface in case the elevation angle (theta) of the antenna apparatus which concerns on Embodiment 3 of this invention is 45 degree | times. Figure showing The top view which looked at the structure of the antenna apparatus which concerns on Embodiment 4 of this invention from the + Z side and -Y side The top view which looked at the structure of the antenna device which concerns on Embodiment 4 of this invention from the -Z side except for the reflecting plate (A) The figure which shows the directivity of the perpendicular | vertical surface of the antenna apparatus which concerns on Embodiment 4 of this invention, (b) The directivity of the conical surface in case the elevation angle (theta) of the antenna apparatus which concerns on Embodiment 4 of this invention is 45 degree | times. Figure showing (A) The top view which looked at the structure of the antenna apparatus which concerns on Embodiment 5 of this invention from the + Z side, (b) The structure of the antenna apparatus which concerns on Embodiment 5 of this invention removes a reflecting plate, and is -Z side Plan view seen from The figure which shows the directivity of the antenna apparatus which concerns on Embodiment 5 of this invention. The figure which shows the structure of the multi-sector antenna of the prior art example 1. The figure which shows the structure of the multi-sector antenna of the prior art example 2. The figure which shows the structure of the multi-beam antenna of the prior art example 3.

Explanation of symbols

101a to 101d Linear element 102a, 102b, 501a, 501b Linear detour element 103, 701, 907, 1104, 1306 Feeding part 104 Reflector 901 Substrate 902 Copper foil layer 903a to 903d Slot element 904a to 904d Connection conductor 905a, 905b Slot detour element 906, 1107a, 1107b, 1303a to 1303f, 1307, 1308a to 1308c Microstrip line 1101, 1304a to 1304c, 1305 Switch 1103, 1105 Copper foil pattern 1106 Through hole

Claims (10)

Four linear elements each having a length of approximately ¼ wavelength to approximately ／ wavelength of the used frequency and arranged in a rhombus shape on a plane;
Power supply means for supplying power to one end of the first linear element and one end of the second linear element;
A folded first linear detour element connected to the other end of the first linear element and one end of the third linear element and having a total length of approximately ¼ wavelength;
A folded second linear detour element connected to the other end of the second linear element and one end of the fourth linear element and having a total length of approximately ¼ wavelength;
A reflector disposed at a predetermined interval substantially parallel to a plane on which the linear elements are disposed;
Comprising
An antenna apparatus, wherein the other end of the third linear element and the other end of the fourth linear element are connected. Four linear elements each having a length of approximately ¼ wavelength to approximately ／ wavelength of the used frequency and arranged in a rhombus shape on a plane;
First feeding means for feeding power to one end of the first linear element and one end of the second linear element;
A second power feeding means for feeding power to one end of the third linear element and one end of the fourth linear element;
A folded first linear detour element connected to the other end of the first linear element and the other end of the third linear element and having a total length of approximately ¼ wavelength;
A second linear detour element having a folded shape connected to the other end of the second linear element and the other end of the fourth linear element and having a total length of approximately ¼ wavelength;
A reflector disposed at a predetermined interval substantially parallel to a plane on which the linear elements are disposed;
An antenna device comprising: A dielectric substrate having a predetermined dielectric constant;
A conductor layer formed on the dielectric substrate surface;
Four slot elements each having a length of approximately 1/4 wavelength to approximately 3/8 wavelength of the operating frequency, and formed in a rhombus shape in the conductor layer;
First feeding means for feeding power at a position where one end of the first slot element and one end of the second slot element are connected;
A folded first slot detour element connected to the other end of the first slot element and one end of a third slot element and having a total length of approximately 1/4 wavelength;
A folded second slot bypass element connected to the other end of the second slot element and one end of the fourth slot element and having a total length of approximately 1/4 wavelength;
A reflector disposed at a predetermined distance from the conductor layer substantially in parallel;
Comprising
An antenna device, wherein the other end of the third slot element and the other end of the fourth slot element are connected. Second power feeding means for feeding power at a position where the other end of the third slot element and the other end of the fourth slot element are connected;
Switching means for selectively switching power supply from the first and second power supply means;
The antenna device according to claim 3, further comprising:   5. The antenna device according to claim 3, wherein a microstrip line provided on a back surface of the substrate on which the conductor layer of the dielectric substrate is formed is used as the power feeding unit.   6. The antenna device according to claim 5, wherein the microstrip line includes switching means for switching between short-circuiting and feeding at a position that is an odd multiple of a quarter wavelength from a coupling portion with the slot element. .   6. The antenna apparatus according to claim 5, wherein the microstrip line includes switching means for switching between open and feed at a position that is an integral multiple of approximately ½ wavelength from the coupling portion with the slot element. .   The inner conductor layer and the outer conductor layer surrounded by the slot elements formed in a rhombus shape are connected to the approximate centers of the four slot elements by connection conductors formed by copper foil patterns, respectively. The antenna device according to any one of claims 3 to 7, wherein the antenna device is characterized.   9. An antenna device using a plurality of antenna devices according to claim 1, wherein the plurality of antenna devices are arranged on a plane while being rotated by equal angles.   The three antenna devices according to any one of claims 4 to 6 are arranged in a line on a straight line, and the three antenna devices are arranged by rotating 60 degrees each. Item 10. The antenna device according to Item 9.

Images