JP3341417B2 - Mobile radio antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna mainly used in mobile radio, and more particularly to an antenna for a base station used in an indoor radio system.

[0002]

2. Description of the Related Art A configuration of a sleeve antenna which is functionally equivalent to a half-wavelength dipole antenna is disclosed in J. J. Dee. Klaus "Antennas" (McGraw-Hill), p. 726 (JDKraus "Antennas" (McGraw-Hill) P726). When the antenna is installed vertically, the sleeve antenna radiates radio waves having omnidirectional vertical polarization in a horizontal plane. The maximum direction of the radiated electromagnetic field generated by the sleeve antenna is perpendicular to the axial direction of the antenna. The sleeve antenna thus satisfies the general requirements as a mobile radio antenna.

In recent years, indoor wireless systems using mobile wireless antennas, such as cordless telephones, used indoors have been actively developed. In an indoor wireless system,
Wireless communication is performed between a master unit having an antenna installed indoors and a slave unit that can move indoors.

[0004]

If the sleeve antenna is used as an antenna for a base unit of an indoor mobile radio system, the following problems are considered to occur. First, since the radio waves radiated from the sleeve antenna show omnidirectionality in the horizontal plane, when the sleeve antenna is mounted on the wall so as to be perpendicular to the floor, the antenna is the same as the power radiated in the indoor direction. Radiates only electric power toward the wall. However, since the parent device communicates with the child device in the room, the radio wave radiated from the antenna of the parent device only needs to be radiated in the indoor direction only, and is radiated toward the wall surface on which the parent device is installed. It is preferable to make the energy of radio waves as small as possible in order to construct an efficient communication system. That is, when the base unit is installed on a wall surface, it is ideal that the directivity of the antenna in the horizontal plane be a fan-shaped directivity so that radio waves are radiated only in the indoor direction. However, as described above, the sleeve antenna is essentially an omnidirectional antenna, and half of the radio wave radiated from the antenna is radiated toward the wall surface, so that the communication with the slave unit, which is the original purpose, is performed. Does not contribute efficiently.

[0005] Further, when a master unit equipped with a sleeve antenna is installed above a ceiling or a wall, the slave unit is located below the master unit. However, since the sleeve antenna radiates the strongest radio waves in the horizontal direction perpendicular to the axis of the antenna, the radiation in the direction of the slave unit is weakened, and the quality of the communication line is degraded.

The present invention has been made in view of such circumstances, and an object of the present invention is to radiate a radio wave, which is stronger than a radio wave directed toward a wall surface, toward a room when an antenna is installed on the wall surface. In addition, by tilting the radiation direction of the radio wave downward from the horizontal direction, the radio wave in the direction of the slave unit is strengthened, and as a result, a mobile radio antenna capable of performing high-quality and stable indoor communication is provided. is there.

Another object of the present invention is to provide an antenna mounted on a ceiling, in which the directivity in a horizontal plane is non-directional, and the direction of radio wave radiation is tilted downward from the horizontal direction so that the direction of the slave unit is reduced. Another object of the present invention is to provide a mobile radio antenna capable of performing high-quality and stable indoor communication by strengthening the radio wave of the mobile radio.

Still another object of the present invention is to provide a mobile radio antenna capable of easily changing a tilt angle.

It is still another object of the present invention to provide a mobile radio antenna capable of easily changing the maximum radiation direction of radio waves.

[0010]

SUMMARY OF THE INVENTION A mobile radio antenna according to the present invention comprises a sleeve antenna having a feed point, at least one linear parasitic element insulated and separated from the sleeve antenna, A supporting means for supporting the parasitic element, wherein the supporting means is rotatable about the axis of the sleeve antenna and moves along the axial direction of the sleeve antenna. Wherein the parasitic element is:
The support means allows the sleeve antenna to be opposed in the axial direction.
The above-mentioned object is achieved.

Further, another mobile radio antenna according to the present invention includes a sleeve antenna having a feed point, at least one linear parasitic element insulated and separated from the sleeve antenna, the sleeve antenna and the radio antenna. A mobile radio antenna comprising: a support means for supporting the feed element,
The support means is rotatable about the axis of the sleeve antenna, and the parasitic element is
It can be moved along the axial direction of the parasitic element.
The parasitic element is supported by the three
The antenna is supported at an angle to the axial direction of the antenna ,
Thereby, the above object is achieved.

[0012] The mobile radio antenna may include first and second parasitic elements supported by the support means.

[0013] The first and second parasitic elements may be arranged symmetrically with respect to a plane including the axis of the sleeve antenna.

[0014] The first and second parasitic elements may be supported by the support means so as to be inclined with respect to the axial direction of the sleeve antenna.

[0015] The mobile radio antenna may include a plurality of parasitic elements supported by the support means.

[0016] Each of the plurality of parasitic elements may be arranged at equal intervals on a circumference around the axis of the sleeve antenna.

[0017] Each of the plurality of parasitic elements may be supported by the support means so as to be inclined with respect to the axial direction of the sleeve antenna.

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

Another mobile radio antenna according to the present invention comprises a sleeve antenna having a feeding point, at least one linear parasitic element insulated and separated from the sleeve antenna, the sleeve antenna and the parasitic antenna. A supporting means for supporting the element and the moving antenna, wherein the supporting means can be moved along the axial direction of the sleeve antenna with respect to the sleeve antenna,
And the antenna is rotatable about the axis of the sleeve antenna, and the parasitic element is supported by the support means so as to be inclined with respect to the axial direction of the sleeve antenna.
Thereby, the above object is achieved.

Another mobile radio antenna according to the present invention comprises a sleeve antenna having a feeding point, a first linear parasitic element and a second linear parasitic element, each of which is insulated and separated from the sleeve antenna. A feed element, the sleeve antenna,
A supporting means for supporting the first parasitic element and the second parasitic element, wherein the supporting means is arranged in the axial direction of the sleeve antenna with respect to the sleeve antenna. It is possible to move along
And the first antenna and the second parasitic element are rotatable about the axis of the sleeve antenna.
The sleeve means is supported by the support means so as to be inclined with respect to the axial direction of the sleeve antenna, and is installed symmetrically with respect to a plane including the axis of the sleeve antenna, thereby achieving the above object. You.

Another mobile radio antenna according to the present invention comprises a sleeve antenna having a feed point, a first linear parasitic element and a second linear parasitic element, each of which is insulated and separated from the sleeve antenna. A feed element and a third linear parasitic element, and support means for supporting the sleeve antenna, the first parasitic element, the second parasitic element, and the third parasitic element. The support means is movable with respect to the sleeve antenna along an axial direction of the sleeve antenna, and is rotatable about the axis of the sleeve antenna; Parasitic element,
The second parasitic element and the third parasitic element are supported by the support means so as to be inclined with respect to the axial direction of the sleeve antenna, and about the axis of the sleeve antenna. They are arranged at equal intervals on the circumference, thereby achieving the above object.

Another mobile radio antenna of the present invention comprises a sleeve antenna having a feeding point, a first linear parasitic element and a second linear parasitic element, each of which is insulated and separated from the sleeve antenna. A feed element, a third linear parasitic element, a fourth linear parasitic element, the sleeve antenna,
A mobile wireless antenna comprising: the first parasitic element, the second parasitic element, the third parasitic element, and support means for supporting the fourth parasitic element. The support means is movable with respect to the sleeve antenna along the axial direction of the sleeve antenna, and is rotatable about the axis of the sleeve antenna, the first parasitic element; The second parasitic element, the third parasitic element, and the fourth parasitic element are supported by the support means at an angle to the axial direction of the sleeve antenna, and the sleeve is The antennas are arranged at equal intervals on a circle around the axis, thereby achieving the above object.

[0039]

The most important feature of the present invention is that the center of the parasitic element is offset from the center of the sleeve antenna, or the axis of the parasitic element is arranged to be inclined from the axis of the sleeve antenna. By doing so, the directivity can be tilted downward from the horizontal plane, and the tilt angle can be changed by changing the magnitude of the offset. Furthermore, by arranging the parasitic elements appropriately, a fan-shaped directivity can be obtained in a horizontal plane that radiates radio waves only in the indoor direction when mounted on a wall, and an omnidirectional pattern can be obtained in a horizontal plane when mounted on a ceiling. Sexual directivity is obtained.

Excellent fan-shaped directivity can be obtained by arranging two parasitic elements symmetrically with respect to a plane including the sleeve antenna. In addition, the non-directionality can be obtained by arranging three or four parasitic elements at equal angular intervals on a circumference around the sleeve antenna. The tilt angle can be changed in the range of 0 to 26 ° by sliding the parasitic element with respect to the sleeve antenna.

The mobile radio antenna according to the present invention is constituted by disposing a parasitic element near the sleeve antenna and has no complicated structure, so that its manufacture is low-cost and easy. Can be done. Further, since the mobile radio antenna of the present invention is compact, it is suitable for indoor use.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the mobile radio antenna according to the present invention will be described below with reference to the drawings.

Embodiment 1 As shown in FIG. 1, a mobile radio antenna according to the present invention comprises a sleeve antenna 106 having a feeding point 104, and a linear parasitic element 107 insulated and separated from the sleeve antenna 106. And support means 1 for supporting sleeve antenna 106 and parasitic element 107
09 and emits a radio wave having a wavelength λ. The sleeve antenna 106 includes a coaxial feed line 101 having an outer conductor and an inner conductor, an antenna element 103, and a metal pipe 102 having a length of λ / 4. In the antenna element 103, the inner conductor extends from the end of the outer conductor (feed point 104) by λ / 4. The metal pipe 102 is placed over the outside of the coaxial feeder 101, and the end of the metal pipe 102 is connected to the outer conductor of the coaxial feeder 101 at the end 104 of the outer conductor.

This mobile radio antenna has a coaxial feed line 1
Coaxial connector 105 connected to the other end of 01
Connected to the radio. The linear parasitic element 107 having a length L is supported by being insulated and separated in parallel with the sleeve antenna 106 by support means 109 made of plastic or the like. The distance d between the sleeve antenna 106 and the parasitic element 107 is set to 1 cm. The length L of the parasitic element 107 is 6 cm, and the diameter is 3 mm.
It is.

The support means 109 is freely rotatable about the axis 110 of the sleeve antenna in the direction indicated by the arrow 111, and may be slid up and down (in the direction of the arrow 112) along the metal pipe 102. it can. As a result, the relative position of the parasitic element 107 with respect to the sleeve antenna 106 can be changed in various ways. The center of the sleeve antenna (feed point 10
4) and the position of the center 108 of the parasitic element can be set at different heights.

The directivity of the antenna shown in FIG. 1 greatly changes depending on the length L and the interval d of the parasitic element. Roughly speaking, when the length L is longer than 波長 wavelength, a beam is generated on the side opposite to the parasitic element, and when shorter than １ ／ wavelength, a beam is generated on the parasitic element side. FIG. 2 shows a case where the position of the feeding point 104 of the sleeve antenna of the present embodiment and the position of the center 108 of the parasitic element are set at the same height.
The directivity of the antenna obtained by calculation is shown.
The calculation was performed by the moment method using an expansion function of a triangular function and a test function. The sleeve antenna was regarded as a dipole antenna having a length of 1/2 wavelength. The length of the equivalent dipole antenna is 7.9 cm and the diameter is 3 mm. The oscillation frequency of the antenna is 1.9 GHz. In FIG. 2, the directivity of the antenna is represented by a linear scale, and xy, zy, z according to the coordinates in the figure.
Vertical polarization components for three planes of the −x plane are displayed. That is, the xy plane is a horizontal plane, zy, zx
The plane represents the directivity of the vertical plane. As can be seen from the figure, a beam is generated on the parasitic element side in the y direction, and the radiation level in the opposite -y direction is 4.7 dB lower than that in the y direction.

FIG. 3A shows a mobile radio antenna 301 having the sleeve antenna 304 and the parasitic element 305 shown in FIG.
FIG. 3 is a view of a state when the camera is attached to a room 3 as viewed from the side of a room. Make the x-axis (perpendicular to the paper) parallel to the wall surface, and
By arranging the antenna 301 so that 6 is on the opposite side to the wall surface 303, the radiation toward the wall surface side is extremely reduced, so that the radiation level in the indoor direction increases and the quality of the communication line increases. The effect of the wall surface on the antenna characteristics can be greatly reduced. ± x
Since the radiation level in the direction is only 1.8 dB lower than in the y direction, a sufficiently strong radio wave is also radiated in the direction along the wall surface. Further, since the mobile radio antenna of the present invention uses the sleeve antenna, the current leaking outside the outer conductor of the coaxial feed line is small, and even when the antenna of the present invention is mounted on a radio and used, Changes in directivity and impedance are small.

FIG. 3 (b) shows a state where the mobile radio antenna 301 of the present invention is mounted on the base unit 302 and the base unit is mounted on the wall surface 303 at the end of the room as viewed from above the room. As described above, since the parasitic element 305 can freely rotate around the sleeve antenna 304, when the parasitic element is attached to the end of the room, the parasitic element is positioned toward the center of the room with respect to the sleeve antenna as shown in the figure. By doing so, the directivity 307 can be directed toward the center of the room. By setting the parasitic element at an appropriate position in this manner, optimal directivity can be realized no matter where the master unit is mounted in the room.

FIG. 4 shows that the supporting means 109 is connected to the metal pipe 10.
2 along the center 10 of the parasitic element 107.
8 is a diagram illustrating a state of the first embodiment in a case where the height of the feeding point is set to be different from the height of the feeding point of the sleeve antenna. FIG. The center 108 of the parasitic element 107 is
It is offset downward by a distance S from the feeding point 104 of the sleeve antenna 106.

FIG. 5 shows a result obtained by calculating the directivity of the antenna at this time. The length L and interval d of the parasitic element are 6 cm and 1 cm, as in the calculation of FIG.
The offset S is 2 cm. Also in this case, it can be seen from the directivity of the xy plane that the radiation in the -y direction is suppressed.
In addition, it can be seen from the directivity in the xy or zx plane that the maximum direction of radiation is tilted downward from the horizontal plane (xy plane). The tilt angle is 7 ° on the xy plane and z-
It is 12 ° in the x plane. Therefore, with such a configuration, when the master unit is installed above the wall near the ceiling, it is possible to efficiently radiate the light toward the slave unit in the room. The directivity of FIG. 2 already described corresponds to the directivity when S = 0, and the tilt angle is 0 at this time. As described above, the tilt angle changes depending on S. When the S is increased, the tilt angle is increased, and when the S is decreased, the tilt angle is decreased. Therefore, in a large room, S can be reduced to reduce the tilt angle, and in a small room, S can be increased to increase the tilt angle, so that radiation can be efficiently emitted toward the child device in the room.

(Embodiment 2) FIG. 6 is a block diagram of another embodiment of the present invention. In this example, the sleeve antenna 106 and the parasitic element 607 are included in the same plane, and the axis of the parasitic element is disposed at an angle γ from the axis of the sleeve antenna. That is, the sleeve antenna 106 and the parasitic element 6
07 are not parallel to each other, but do not have a twisted relationship. FIG. 7 shows the result of calculating the directivity of the present embodiment. The length L, spacing d and offset S of the parasitic element are 6 cm and 1 cm, respectively, as in the embodiment shown in FIG.
And 2 cm. The inclination angle γ is 30 °. As can be seen from FIG. 7, the tilt angle on the xy plane is 11 °. That is, by tilting the parasitic element, the tilt angle in the y direction can be made larger than in the case shown in FIG. Therefore, by using such an antenna, radio waves can be more efficiently radiated toward the slave unit when the installation position of the master unit is high or in a small room.

In the second embodiment, as in the first embodiment, the support means 609 is provided on the shaft 11 of the sleeve antenna 106.
It can freely rotate around the sleeve antenna as indicated by an arrow 611 around 0, and moves up and down (in the direction of arrow 612) along the axis of the sleeve antenna as indicated by an arrow 612. I can do it. Therefore, the function of rotating the parasitic element around the sleeve antenna to control the directivity and the function of changing the tilt angle by the offset S in the second embodiment are the same as those in the first embodiment.

In this embodiment, the length L of the parasitic element is 6
Although the description has been made on the assumption that the distance d is 1 cm, the interval d is 1 cm, the offset S is 2 cm, and the inclination angle γ is 30 °, it is needless to say that a preferable directivity can be realized with other values. For example, if L is shorter than 6 cm in the first embodiment, the directivity becomes broader than the directivity shown in FIG. 2, and if L is made longer than the sleeve antenna to about 8 cm,
The beam can be made in the opposite direction to the parasitic element. Therefore, the most appropriate directivity for the system can be realized by selecting these parameters.

(Embodiment 3) FIG. 8 is a block diagram of a third embodiment of the present invention. The mobile radio antenna according to the present embodiment includes:
The antenna includes a sleeve antenna 106 and two linear parasitic elements 807 and 808 having a length L. The parasitic element is
It is separated and insulated from the sleeve antenna by the support means 809 made of plastic or the like, and is supported by the sleeve antenna. As shown by an arrow 811, the sleeve antenna is free to rotate around the axis 110 of the sleeve antenna. It can rotate. The support means 809 can slide along the metal pipe 102 so that the parasitic elements 807 and 808 can move up and down along the axis 110 of the sleeve antenna as indicated by an arrow 812.

FIG. 9 is a perspective view showing the dimensions and the positional relationship of each part of the antenna shown in FIG. FIGS. 10A and 10B show a plan view and a side view of FIG. 9 so that the positional relationship can be understood more easily. x, y,
The origin of the z coordinate is centered on the sleeve antenna 106,
The z axis is aligned with the axis of the sleeve antenna. Each axis of the parasitic elements 807 and 808 is inclined by an angle γ from an axis 901 parallel to the z-axis. Parasitic elements 807 and 808
Are both L. The lower end 902 of the parasitic element is on a circle having a radius d centered on a point 903 on the z-axis. The distance between the point 903 and the origin is S + (L / 2) cosγ.
Therefore, the midpoint 904 of the parasitic element is offset by S from the xy plane as shown in FIG. The lower end 902 of the parasitic element is located at an opening angle α from the y-axis. Also, as shown in FIG. 10A, the angle between the mapping of the parasitic element on the xy plane and the axis 905 parallel to the y-axis is β. As described above, the two parasitic elements are positioned on the zy plane including the axis of the sleeve antenna.
They are arranged symmetrically to each other.

FIG. 11 shows a result obtained by calculating the directivity of this embodiment. The length of the sleeve antenna is 7.9 cm, the length L of the parasitic element is 6 cm, and the interval d is 1
cm, offset S is 2 cm, angle is α = 60 °, β =
80 ° and γ = 30 °. The frequency of the radio wave radiated from the sleeve antenna is 1.9 GHz. The display is a linear scale and is standardized by the maximum value (0.93 dBd). As can be seen from FIG. 11, the directivity in the xy plane is stronger in the + y direction than in the -y direction. The radiation in the ± x direction is almost the same as the radiation in the + y direction, and has a characteristic of radiating a fan shape in the + y direction more uniformly than the x axis. Next, from the calculated values of directivity in the xy and zx planes, the maximum directions of radiation in the + y direction and the ± x direction are tilted downward from the horizontal plane (xy plane). Understand. The tilt angle is 16 on the xy plane.
゜, 18 ° in the zx plane. Also, from these directivities,
It can be seen that even in the maximum radiation direction, the radiation levels in the + y direction and the ± x direction are almost the same. In the case where there is one parasitic element as in the first embodiment or the second embodiment, FIG.
Alternatively, as can be seen from FIG. 7, the radiation level in the x direction is smaller than in the y direction. On the other hand, by arranging two parasitic elements as shown in FIG. 8, a fan-shaped directivity can be obtained. Note that this embodiment is also similar to the first embodiment.
The support means 809 for supporting the parasitic element can freely rotate around the sleeve antenna as shown by an arrow 811 around the axis 110 of the sleeve antenna. Therefore, when this embodiment is attached to the edge of the room, the parasitic element can be appropriately rotated around the sleeve antenna, and the directivity of the antenna can be directed toward the center of the room. In addition, the supporting means is moved in the vertical direction (arrow 812) along the sleeve antenna, and the center position (feed point) of the sleeve antenna and the center positions of the plurality of parasitic elements are set to different heights. Is also possible.

FIG. 12 shows a change in the tilt angle due to a change in the offset S when the center of the parasitic element is offset from the xy plane. Solid line 1201 is +
The tilt angle in the y direction is shown, and the solid line 1202 is ± x
It represents the tilt angle of the direction. In this case, even if the offset S is changed, the directions of the maximum radiation level in the + y direction and the ± x direction substantially match. That is, even if S is changed,
The directivity of the sector in the + y direction on the xy plane described in FIG. 11 does not change much. As can be seen from FIG.
By changing S, the tilt angle becomes 0 in the + y direction.
゜ 20 °, ± 8 ° in the ± x direction. Therefore, in a large room, S can be reduced to reduce the tilt angle, and in a small room, S can be increased to increase the tilt angle, so that radiation can be efficiently emitted toward the child device in the room. That is, an optimum tilt angle according to the size of the room can be obtained.

FIG. 13 shows a gain difference ΔG between the y direction and the ± x direction.
6 is a graph showing the relationship between the opening angles α and β. This graph was obtained by calculation with the length of the sleeve antenna 106 being 7.9 cm, the length L of the parasitic elements 807 and 808 being 6 cm, the interval d being 1 cm, and the angle γ being 30 °. The calculation was performed on the assumption that the frequency of the radio wave radiated from the sleeve antenna was 1.9 GHz. X- when ΔG = 0
The directivity in the y-plane becomes almost fan-shaped. α is 40 °,
At 60 ° and 80 °, there is a β of ΔG = 0, whose values are β = 67 °, 80 ° and 100 °, respectively. Thus, by appropriately selecting β for a specific value of α,
A fan-shaped directivity can be obtained. According to the calculation, the directivity under the above three conditions was almost the same.

(Embodiment 4) FIG. 14 is a block diagram showing a fourth embodiment of the present invention. The mobile radio antenna of this embodiment includes the sleeve antenna 106 and three linear parasitic elements 1407, 1408, and 1409 having a length L. The parasitic element is supported by the sleeve antenna by support means 1411 made of plastic or the like, and can freely rotate around the sleeve antenna as shown by an arrow 1413 around the axis 1412 of the sleeve antenna. It has become. Also, the support means 141
1 can slide along the metal pipe 102 so that the parasitic elements 1407, 1408, 1409 cause the axis 141 of the sleeve antenna, as indicated by the arrow 1414, to move.
2 can be moved up and down.

FIGS. 15 (a) and 15 (b) correspond to FIG.
3A and 3B are a perspective view and a plan view showing the dimensions and positional relationship of each part of the antenna shown in FIG. The origin of the x, y, and z coordinates is set at the center of the sleeve antenna 106, and the z axis is aligned with the axis of the sleeve antenna. Parasitic elements 1407, 1408 and 1
Each axis 409 is inclined by an angle γ from an axis 1501 parallel to the z-axis. The length of each parasitic element is L.
The parasitic element is on the plane formed by the axis 1501 and the z-axis. The upper end 1502 of the parasitic element is a point 1503 on the z-axis.
At equal intervals on the circumference of radius d centered at (equivalent to 120 degrees)
Are located in The distance between the point 1503 and the origin is S + (L
/ 2) cosγ. Therefore, the midpoint 15 of the parasitic element
04 is offset by S from the xy plane.

FIG. 16 shows a result obtained by calculating the directivity of this embodiment. The length of the sleeve antenna is 7.9 cm, the length L of the parasitic element is 6 cm, and the interval d is 1
cm, the offset S is 2 cm, and the angle γ is 30 °.
The oscillation frequency of the antenna is 1.9 GHz. The display is a linear scale, which is standardized by the maximum value (0.7 dBd). As can be seen, the directivity in the xy plane is almost non-directional. Also, from the calculated values of the directivity in the xy and zx planes, it can be seen that the maximum direction of the radiation is tilted upward from the horizontal plane (xy plane). The tilt angle is about 24 °.

FIG. 17 shows a mobile radio antenna 1701 of the present invention shown in FIG.
FIG. 706 is a view when the camera is attached to a room 706 viewed from the side of a room. When the antenna is mounted in this manner, directivity 17
As indicated by 08, the maximum radiation direction of the radio wave is tilted downward, so that the child device in the room can be efficiently radiated.

FIG. 18 shows a change in the tilt angle with respect to a change in the offset S when the midpoint of the parasitic element is offset from the xy plane. As can be seen from FIG. 18, by changing S, the tilt angle becomes 8 to
It can be changed in the range of 26 °. Therefore, in a large room, S can be reduced to reduce the tilt angle, and in a small room, S can be increased to increase the tilt angle, so that radiation can be efficiently emitted toward the child device in the room. That is, an optimum tilt angle according to the size of the room can be obtained. Also, as in the other embodiments of FIG. 14, the supporting means 1411 can freely rotate about the sleeve antenna 106, so that when the antenna is mounted on the ceiling, a good wireless communication can be achieved even if the parasitic element is installed at a position that is aesthetically pleasing. Communication can be performed.

(Embodiment 5) FIG. 19 shows the configuration of a fifth embodiment of the present invention. FIG. 20A and FIG.
0 (b) is a perspective view and a plan view showing the dimensions and the positional relationship of each part of the embodiment shown in FIG. 19 and 20
14 and 15 have the same functions as those in FIGS. In this embodiment, four parasitic elements 1 are used.
407, 1408, 1409 and 1410. The parasitic element is supported by the sleeve antenna by supporting means 1911 made of plastic or the like.
As shown at 913, it can be freely rotated around the sleeve antenna. Also, the support means 1911
Can slide along the metal pipe 102 so that the parasitic elements 1407, 1408, 1409, 141
The 0 can be moved up and down along the axis 1412 of the sleeve antenna, as indicated by the arrow 1914. Parasitic elements 1407, 1408, 1409 and 14
10 is inclined by an angle γ from an axis 1501 parallel to the z-axis. The length of each parasitic element is L. The parasitic element is on the plane formed by the axis 1501 and the z-axis. The upper ends 1502 of the parasitic elements are arranged at equal intervals (equivalently at 90 degrees) on a circumference having a radius d around a point 1503 on the z-axis. The distance between the point 1503 and the origin is S + (L / 2) co
sγ. Therefore, the midpoint 1504 of the parasitic element is x
It is offset by S from the -y plane. The length of the sleeve antenna of this embodiment is 7.9 cm, the length L of the parasitic element is 6 cm, the interval d is 1 cm, and the offset S is 2c.
m and the angle γ were 30 °.

FIG. 21 shows the calculation result of the directivity of this embodiment. This calculation was performed assuming that the frequency of the radio wave radiated from the sleeve antenna was 1.9 GHz. In FIG. 21, the directivity is displayed on a linear scale, and the maximum value (0.
55 dBd). As can be seen from FIG. 21, the directivity in the xy plane is almost non-directional. Also, from the calculated values of the directivity in the xy and zx planes, it can be seen that the maximum direction of radiation is tilted upward from the horizontal plane (xy plane). The tilt angle is about 24 °.

Also in this embodiment, the change of the tilt angle when the offset S is changed is almost the same as that shown in FIG. Therefore, when the antenna of this embodiment is used, the same effect as that described with reference to FIG. 17 can be obtained. However, as can be seen from the directivity of the xy plane shown in FIG.
The directivity in the horizontal plane is closer to a circle, and the directivity of the antenna is closer to the non-directionality, as compared with the three cases in FIG.

Further, in each of the above embodiments, the dimension parameter of each part of the antenna has been described using one example. However, it is needless to say that a preferable directivity according to the application can be realized with other numerical values. For example, the case where the parasitic element is inclined with respect to the axis of the sleeve antenna has been described using the fourth and fifth embodiments, but according to calculations, even if both are parallel, the centers of each other are offset. Then, the directivity can be tilted. However, the tilt angle is smaller than when the parasitic element is inclined with respect to the axis of the sleeve antenna.

In the fourth and fifth embodiments, the parasitic element is inclined such that the inclination of the parasitic element approaches the sleeve antenna toward the tip of the sleeve antenna, that is, the + z direction.
On the contrary, the antenna is inclined toward the lower end of the sleeve antenna, that is, toward the −z direction, so that the center of the parasitic element is lower than the center of the sleeve antenna (−
(z direction), the tilt direction can be directed downward from the xy plane.

In each of the above embodiments, the description has been made using the calculated value by the moment method. However, it has been confirmed by an experiment that the measured value agrees very well with the calculated value.

In each of the above embodiments, the movement of the parasitic element is performed by sliding the supporting means along the axis of the sleeve antenna. However, the parasitic element of each embodiment is moved with respect to the supporting means. The structure can be made to be slidable along the axis of the parasitic element, whereby the same effect as in the above embodiment can be obtained. Further, when the antenna is mounted on a wireless device, the entire sleeve antenna may be covered with an insulator to protect the sleeve antenna from damage. Also in this case, the same effect can be obtained by moving the parasitic element along the insulator.

Although the support means of each of the above embodiments is rotatable and movable with respect to the sleeve antenna, if it is not necessary to change the directivity of the antenna, the antenna of the present invention may be replaced with a sleeve antenna. In addition, the passive element and the supporting means may be produced in a fixed form.

In the above description, the case where the antenna is used for an indoor wireless system has been mainly described. However, the antenna of the present invention can be used for an outdoor wireless system.

[0073]

According to the present invention, even when the mobile radio antenna is installed on a wall or a ceiling, by appropriately arranging the sleeve antenna and the parasitic element, the antenna moves toward the room toward the wall. It is possible to emit radio waves more strongly and to tilt the radiation direction of the radio waves downward from the horizontal direction. As a result, when the antenna of the present invention is mounted on the base unit and used, the radio waves directed to the slave unit can be made relatively stronger than the radio waves directed to other directions, and high-quality and stable indoor communication can be achieved. It is possible to do.

According to the present invention, even when the antenna is mounted on the wall surface, the radiation level of the radio wave toward the wall surface can be extremely reduced by positioning the parasitic element with respect to the sleeve antenna toward the center of the room. As a result, the radiation level of the radio wave in the indoor direction increases, the quality of the communication line increases, and the effect of the wall surface on the antenna characteristics can be greatly reduced. In addition, by sliding (offset) the parasitic element along the axis of the sleeve antenna and changing the tilt angle, it is possible to efficiently radiate radio waves toward the child device in the room even in a large room or a small room. It becomes possible.

According to the present invention, the tilt angle can be further increased by arranging the axis of the parasitic element at an angle to the axis of the sleeve antenna, and the tilt angle of the master unit to which the antenna of the present invention is attached can be increased. Regardless of the installation position, it is possible to more efficiently radiate radio waves from the master unit to the slave units.

Further, according to the present invention, a fan-shaped directivity can be obtained by arranging the two parasitic elements so as to be symmetrically inclined with respect to a plane including the axis of the sleeve antenna. . Further, when the antenna of the present invention is attached to the end of the room, the parasitic element can be rotated around the sleeve antenna to direct the directivity toward the center of the room. Further, in a large room, the offset is reduced to reduce the tilt angle, and in a small room, the offset is increased and the tilt angle is increased, so that it is possible to radiate the light efficiently toward the child device in the room.

Furthermore, according to the present invention, even when the mobile radio antenna is installed on the ceiling, three or four linear parasitic elements are arranged around the axis of the sleeve antenna. By arranging them at equal intervals on the circumference and tilting them, the directivity in the horizontal plane approaches non-directionality, and the radiation direction of the radio waves is tilted downward from the horizontal direction to strengthen the radio waves in the direction of the slave unit. can do. As a result, high-quality and stable indoor communication can be performed using the antenna of the present invention.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a mobile radio antenna according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing directivity of the first embodiment of the present invention.

FIG. 3 is a diagram showing a state where the mobile radio antenna according to the first embodiment of the present invention is mounted on a wireless device and mounted on a wall surface.

FIG. 4 is a configuration diagram when the center of the parasitic element according to the first embodiment of the present invention is offset from the center of the sleeve antenna.

FIG. 5 is a characteristic diagram showing directivity when the center of the parasitic element according to the first embodiment of the present invention is offset from the center of the sleeve antenna.

FIG. 6 is a configuration diagram of a mobile radio antenna according to a second embodiment of the present invention.

FIG. 7 is a characteristic diagram showing directivity according to a second embodiment of the present invention.

FIG. 8 is a configuration diagram of a mobile radio antenna according to a third embodiment of the present invention.

FIG. 9 is a perspective view showing dimensions and a positional relationship of each part according to a third embodiment of the present invention.

FIG. 10 is a view showing dimensions and positional relationships of respective parts according to a third embodiment of the present invention.

FIG. 11 is a characteristic diagram showing directivity according to a third embodiment of the present invention.

FIG. 12 is a characteristic diagram showing a relationship between an offset S and a tilt angle according to a third embodiment of the present invention.

FIG. 13 is a graph showing the relationship between the gain difference ΔG in the y direction and ± x direction and the opening angles α and β in the third embodiment of the present invention.

FIG. 14 is a configuration diagram of a mobile radio antenna according to a fourth embodiment of the present invention.

FIG. 15 is a diagram showing dimensions and positional relationships of respective parts according to a fourth embodiment of the present invention.

FIG. 16 is a characteristic diagram showing directivity according to a fourth embodiment of the present invention.

FIG. 17 is a side view of a state where the fourth embodiment of the present invention is mounted on a wireless device and mounted on a ceiling as viewed from the side.

FIG. 18 is a characteristic diagram showing a relationship between an offset S and a tilt angle according to a fourth embodiment of the present invention.

FIG. 19 is a configuration diagram of a mobile radio antenna according to a fifth embodiment of the present invention.

FIG. 20 is a diagram showing dimensions and positional relationships of respective parts according to a fifth embodiment of the present invention.

FIG. 21 is a characteristic diagram showing directivity according to a fifth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Coaxial feed line 102 Metal pipe 103 Antenna element 105 Coaxial connector 107 Parasitic element 109 Support jig

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-51607 (JP, A) JP-A-50-117343 (JP, A) JP-A-2-224407 (JP, A) 81016 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01Q 9/18 H01Q 3/20 H01Q 19/24 H01Q 19/30

Claims (9)

(57) [Claims] A sleeve antenna having a feeding point, at least one linear parasitic element insulated and separated from the sleeve antenna, and support means for supporting the sleeve antenna and the parasitic element are provided. a mobile radio antenna, the support means is rotatable about the axis of the sleeve antenna, and it is possible to move along the axial direction of the sleeve antenna, the wireless power feeding element
Is the axial direction of the sleeve antenna by the support means.
A mobile radio antenna that is supported at an angle with respect to . A sleeve antenna having a feeding point, at least one linear parasitic element insulated and separated from the sleeve antenna, and support means for supporting the sleeve antenna and the parasitic element. A mobile wireless antenna, wherein the support means is rotatable about an axis of the sleeve antenna, and the parasitic element is moved relative to the support means in an axial direction of the parasitic element. Wherein the parasitic element is provided by the support means.
The sleeve antenna is supported to be inclined with respect to the axial direction.
And it has a mobile radio antenna. 3. The mobile radio antenna according to claim 1, wherein the mobile radio antenna has first and second parasitic elements supported by support means. 4. The mobile radio antenna according to claim 3, wherein the first and second parasitic elements are arranged symmetrically with respect to a plane including the axis of the sleeve antenna. 5. The mobile radio antenna according to claim 1, wherein the mobile radio antenna has a plurality of parasitic elements supported by a support means. 6. The mobile radio antenna according to claim 5 , wherein each of the plurality of parasitic elements is arranged at equal intervals on a circumference around the axis of the sleeve antenna. 7. A sleeve antenna having a feeding point, a first linear parasitic element and a second linear parasitic element, each of which is insulated and separated from the sleeve antenna; 1. A mobile radio antenna comprising: a first parasitic element and a supporting unit for supporting the second parasitic element, wherein the supporting unit is arranged along an axial direction of the sleeve antenna with respect to the sleeve antenna. Being moveable and rotatable about the axis of the sleeve antenna, the first parasitic element and the second parasitic element are coupled to the axis of the sleeve antenna by the support means. A mobile radio antenna supported to be inclined with respect to a direction and installed symmetrically with respect to a plane including the axis of the sleeve antenna. 8. A sleeve antenna having a feeding point, a first linear parasitic element, a second linear parasitic element, and a third linear parasitic element, each of which is insulated and separated from the sleeve antenna. A parasitic element and supporting means for supporting the sleeve antenna, the first parasitic element, the second parasitic element, and the third parasitic element, wherein the supporting means includes the sleeve The first parasitic element, the second parasitic element, the antenna element being movable with respect to the antenna along the axial direction of the sleeve antenna, and rotatable about the axis of the sleeve antenna. The element and the third parasitic element are supported by the support means so as to be inclined with respect to the axial direction of the sleeve antenna, and are equally spaced on a circumference centered on the axis of the sleeve antenna. Mobile wireless network Tena. 9. A sleeve antenna having a feeding point, a first linear parasitic element, a second linear parasitic element, and a third linear parasitic element, each of which is insulated and separated from the sleeve antenna. A parasitic element and a fourth linear parasitic element, the sleeve antenna, the first parasitic element, the second parasitic element, the third parasitic element, and the fourth parasitic element And a supporting means for supporting the mobile radio antenna,
The support means is movable with respect to the sleeve antenna along an axial direction of the sleeve antenna, is rotatable about the axis of the sleeve antenna, and is provided with the first parasitic element. , The second parasitic element,
The third parasitic element and the fourth parasitic element are supported by the support means so as to be inclined with respect to the axial direction of the sleeve antenna, and about the axis of the sleeve antenna. Mobile radio antennas arranged at equal intervals on the circumference.