JPH08265237A - Diversity receiver - Google Patents

Abstract

PURPOSE: To provide a diversity receiver capable of maintaining a small correlation coefficient between diversity antennas and performing high quality transmission even when a base station antenna is installed on a road where people or the like pass. CONSTITUTION: Diversity receiver antennas are arranged so as to make an angle α16, between a straight line 13 which is the projection, on the surface of a road 19, of a straight line connecting the power feed point 11 of an antenna A and the power feed point 12 of an antenna B separated by a distance d14, and a straight line 15 perpendicular to the width direction 20 of the road 17, be 55 deg.<=α<=65 deg. or 25 deg.<=α<=35 deg.. Then, the plural antennas are arranged so as to make the angle α formed by the straight line perpendicular to the width direction of the road and the arrangement direction of the power feed points of the diversity antennas be 55 deg.<=α<=65 deg. or 25 deg.<=α<=35 deg.. Thus, even when the base station antenna is installed on the road, since the correlation coefficient between the diversity antennas can be made small, the high quality transmission of small error rate characteristics is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity receiver having a small correlation coefficient between antennas forming a diversity system and capable of high quality transmission.

[0002]

2. Description of the Related Art A spatial diversity reception method is an effective means for improving multi-wave interference fading, which is a main cause of deterioration of mobile communication quality in urban areas. This space diversity is a method of obtaining a received signal with a small correlation by spatially separating two or more receiving antennas.
It is widely used because it simplifies the configuration of the antenna system. To obtain an effective diversity effect, the journal of the Institute of Electronics, Information and Communication Engineers, B Vol. J68-B No. 2 (1985) No. 2
As discussed from pages 28 to 235, it is necessary to lower the correlation coefficient between diversity antenna branches, and generally the correlation coefficient should be 0.6 or less.

The correlation characteristic in this space diversity has been examined by experiments and theoretical calculations. Regarding the correlation characteristic of conventional space diversity in urban areas, the journal of the Institute of Electronics, Information and Communication Engineers B Vol. J70-B No. 4 (198)
7 years) pp. 476 to 482, and IEE, Proceedings, Volume 133 Part F Number 6 (1986) 506 to 512 (IEE Proceedings, Vol. 133, Pt. F, No.
6 (1986) PP506-512). Here, the angle α formed by the direction in which the diversity antennas are arranged in the base station and the direction of arrival of the multiple waves is 90 ° (that is, the multiple waves are incident perpendicularly to the line connecting the antennas).
It is known that the correlation coefficient becomes the smallest and that the correlation coefficient becomes larger as the arrival angle α becomes smaller.

[0004]

In the diversity receiver according to the above-mentioned prior art, the base station antenna is installed at a position higher than the surrounding buildings. Therefore, it can be approximated that the multiple waves arriving at the base station almost arrive from the mobile station. FIG. 10 shows a conventional multi-wave arrival model between a mobile station and a base station. The radio wave transmitted from the mobile station 101 is reflected and diffracted by a building existing in a plane surrounded by a circle 102 having a radius r, and then forms an arrival angle α16,
It arrives at the antennas 11 and 12 of the base station. Here, by assuming the level distribution of the multiple waves arriving at the base station, the correlation coefficient for the diversity antenna interval 14 can be obtained by theoretical calculation. As described above, in the propagation of radio waves in the conventional mobile communication, it can be considered that the multiple waves coming to the base station come from one direction, which is the direction of the mobile station 101. Further, the arrival angle α16 of the multiple waves to the installed base station antennas 11 and 12 changes variously depending on the direction in which the mobile station is located.

However, when the antenna height of the base station becomes low, the radio wave is reflected from a wide area and reaches the base station. For this reason, it has become difficult to predict the theoretical value of the correlation coefficient in the multiple wave arrival model in the above-described conventional technology that considers only the arrival wave from the mobile station direction. For personal handyphone systems, which are expected to become popular in the future, base stations are being considered for installation on telephone poles, public telephone boxes, and traffic signals, and the antenna height will be much lower than before. In this way, when the antennas of the base station and mobile station are both lower than the height of buildings such as surrounding buildings, waves propagating along the road become dominant.
Therefore, unlike the multiple wave arrival model in the above-mentioned conventional technology, strong waves do not mainly arrive at the base station from one direction toward the mobile station, but waves with different intensities from multiple directions along the road. It is possible that they will arrive. with this,
The spatial diversity correlation characteristics at the base station are also different from conventional ones.

An object of the present invention is to provide a diversity receiver having a small correlation coefficient between diversity antennas and capable of high quality transmission even when the base station antenna is installed at a position lower than the surrounding buildings. is there.

[0007]

In order to achieve the above-mentioned object, in the diversity receiver of the present invention, a straight line connecting the feeding points of the diversity antenna to the straight line perpendicular to the width direction of the road is set on the road surface. The angle α of the straight line obtained by projecting is 55 ° ≦ α ≦ 65 ° or 25 ° ≦
It is characterized in that a plurality of antennas are arranged so that α ≦ 35 °.

Alternatively, a tangent line at an intersection of a straight line connecting the feeding points of the diversity antenna with a straight line obtained by projecting the feeding point of the diversity antenna onto a road surface with respect to a curve representing an end of an arbitrary shape, and the feeding point of the antenna The angle α with the straight line obtained by projecting the straight line connecting
It is characterized by arranging a plurality of antennas so that ° ≦ α ≦ 65 ° or 25 ° ≦ α ≦ 35 °.

Alternatively, the angle α formed by projecting a straight line connecting the feeding points of the diversity antenna onto the bottom surface of the housing with respect to the side surface of the housing is 55 ° ≦ α ≦
A plurality of antennas are arranged so that 65 ° or 25 ° ≦ α ≦ 35 °.

[0010]

According to the present invention, the straight line obtained by projecting the straight line connecting the feeding points of the diversity antenna on the road surface, the straight line perpendicular to the width direction of the road, or the side surface of the housing. Angle α is 55 ° ≦ α ≦ 65 ° or 25
By arranging a plurality of antennas so that ° ≦ α ≦ 35 °, the phase difference relation between the elementary waves forming the multiple waves can be 2 with respect to the multiple waves arriving from multiple directions along the road. Since it can be increased between two antennas, the correlation between the antennas becomes smaller. Thereby, high quality transmission can be realized in mobile communication.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a relationship between a road and an antenna position of a diversity receiver according to an embodiment of the present invention. A diversity receiver having an antenna A and an antenna B is installed in the intersection 21 of the road, and the antenna A
The straight line 13 obtained by projecting the straight line connecting the feeding point 11 of the antenna B and the feeding point 12 of the antenna B onto the road surface 19 is perpendicular to the width direction 20 of one of the intersecting roads 17. An angle α16 is formed with respect to the straight line 15 on the road surface. Here, the angle α16 is the angle α1, α2 (α1 ≦ α2, α1 + α2) formed by the straight line 13 and the straight line 15.
= 180 °), the smaller angle α1. 18
Is a building, and the distance between the feeding point 11 of the antenna A and the feeding point 12 of the antenna B is d14. The heights of the feeding point 11 of the antenna A and the feeding point 12 of the antenna B from the road surface 19 may be different or the same. The feature of this embodiment is that the feeding point 11 of the antenna A and the feeding point 12 of the antenna B are
The angle α formed by projecting a straight line connecting the two to the road surface 19 and a straight line 15 on the road surface perpendicular to the width direction 20 of one of the intersecting roads 17
16 is where the diversity receiver antenna is arranged so as to be 60 ° or 30 °. As a result, even when the base station antennas are installed in the same way, the correlation coefficient between the diversity antennas can be reduced and high quality transmission can be performed.

Here, in order to explain this embodiment in detail, FIG. 12 shows the correlation coefficient with respect to the antenna spacing when multiple waves arrive from a plurality of directions. As shown in FIG. 11, the diversity receiver of the base station is installed at (a) an intersection and (b) a straight road.
It is assumed that the data come from 4 directions and 2 directions along 7, respectively. The average received power of multiple waves is
On the other hand, the arriving waves B112, C113, and D114 are 1 /
It has a strength of 2. In addition, incoming waves A111, B11
It is assumed that the level distributions of 2, C113 and D114 are normal distributions with a standard deviation of 5 ° and reach the antennas A11 and B12. 12 (a), (b),
(C) and (d) show the incoming wave A11 having the maximum reception level.
The arrival angle α16 of 1 is 90 °, 60 °, 45, respectively.
It shows the case where the angle is 30 °. As can be seen from FIG. 12, when multiple waves arrive from a plurality of directions, the correlation coefficient fluctuates greatly due to changes in the antenna spacing d14. When arriving from four directions, when the arrival angle α16 of the arriving wave A111 is 60 ° and 30 ° rather than 90 ° and 45 °, the variation of the correlation coefficient due to the change of the antenna spacing d14 becomes smaller, and the antenna spacing 1 Correlation coefficient is almost 0 at ~ 2λ
A good correlation characteristic close to is obtained. When multiple waves arrive from two directions, the arrival angle α16 of the arrival wave A111 is 60.
At °, the fluctuation of the correlation coefficient is the smallest and good correlation characteristics are obtained. In this way, when multiple waves arrive from multiple directions, the correlation characteristics show a strong dependence on the antenna spacing and the direction of arrival of multiple waves, with the same tendency as in the case of conventional arrival from only one direction. Don't From the above, when multiple waves arrive from multiple directions,
6 rather than installing a plurality of antennas 11 and 12 so that the incoming wave α16 is 90 ° with respect to the incoming wave A111 of
When the antennas 11 and 12 are installed so as to be 0 ° or 30 °, the correlation coefficient with respect to the antenna interval d14 becomes smaller.

When the road width is wide, the number of routes of reflected waves that can reach the base station increases, so that the standard deviation of the level distribution of the incoming waves 111, 112, 113, and 114 that arrive at the base station is large. Become. Therefore, the correlation coefficient becomes smaller than the result of FIG. 12, and the antenna spacing d1
The variation of the correlation coefficient depending on 4 becomes small. In Figure 13,
The correlation coefficient for the antenna spacing is shown when the standard deviation of the level distribution of the arriving wave is changed. In this way, when the standard deviation of the level distribution of the incoming wave is large, the correlation coefficient is small, and the variation of the correlation coefficient due to the change of the antenna spacing d14 is small. Furthermore, the incoming wave A1 in FIG.
As compared with 11, the smaller the average received power of the incoming waves B112, C113, and D114, the smaller the variation of the correlation coefficient depending on the antenna interval d14. In addition, in actual propagation, in addition to waves propagating along the road, waves diffracted at the upper end of the building are added, so the standard deviation of the amplitude of the arriving wave arriving at the base station increases, and the correlation coefficient is It is expected to be even smaller than the results using the above model.
However, in any case, the correlation characteristics depending on the arrival angle α16 when the multiple waves arrive from a plurality of directions are similar to the results obtained in FIG. , 60 °, 30 °, the variation of the correlation coefficient due to the change of the antenna distance d14 tends to be smaller.

Here, since the multiple waves propagate along the road 17, the arrival direction of the arrival wave A111 and the straight line perpendicular to the width direction of the road can be regarded as substantially parallel.

Based on the above, if a plurality of antennas are arranged at 60 ° or 30 ° with respect to a straight line perpendicular to the width direction of the road, even when the base station antenna is installed in the street, As is clear from FIG. 12, the correlation coefficient between diversity antennas can be reduced.

Further, even when a plurality of antennas are arranged at 55 ° ≦ α ≦ 65 ° or 25 ° ≦ α ≦ 35 ° with respect to a straight line perpendicular to the width direction of the road, a small correlation coefficient is similarly obtained. Is obtained.

Next, the positional relationship between the direction of the current component contributing to the radiation induced in the antenna of the diversity receiver of the present invention and the road will be described with reference to FIGS. In Figure 5,
The antennas A and B are arranged such that the directions 51 and 52 of the current components that contribute to the radiation induced in the antennas A and B are perpendicular to the road surface 19, respectively. In FIG. 6, the directions of current components 51 and 52 that contribute to the radiation induced in the antennas A and B are parallel to the road surface 19 and perpendicular to the width direction 20 of the road. And the antenna B is arranged.
Further, in FIG. 7, the directions 51 and 52 of the current components contributing to the radiation induced in the antenna A and the antenna B are parallel to the road surface 19 and parallel to the width direction 20 of the road. Antenna A and antenna B are arranged. In this way, the antenna A and the antenna B are arranged so that the directions 51 and 52 of the current components contributing to the radiation induced in the antenna A and the antenna B are located in any of the directions shown in FIGS. Even at times, the diversity receiver according to the present invention can reduce the correlation coefficient with respect to the antenna spacing 14. Further, the same holds true even when the directions 51 and 52 of the current components contributing to the radiation induced in the antenna in FIGS. 5 to 7 are opposite to the arrows.

Here, the antenna may be installed on any structure such as a telephone pole, a public telephone box, a traffic signal, or a wall surface of a building.

As can be seen from FIG. 12, when the antenna spacing d14 is λ / 4 <d <5λ, the effect of minimizing the correlation coefficient between them is exhibited. Here, λ is a wavelength, and for example, when the frequency of the radio wave is 1.9 GHz, λ is about 16 cm.

Further, the antenna A11 and the antenna B1
As 2, a monopole antenna, a dipole antenna, a microstrip antenna, or a slot antenna can be used. Alternatively, any one of a monopole antenna, a dipole antenna, a microstrip antenna, and a slot antenna can be used for each of the antenna A11 and the antenna B12. In any case, the diversity receiver of the present invention has the effect of reducing the correlation coefficient for the antenna spacing 14.

Further, the diversity receiver of the present invention can be used in combination with any combined reception method such as selective combining, equal gain combining, and maximum ratio combining. For example, in the error rate characteristic of differential detection when the selective combining method is used, the ratio of the signal power S and the noise power N required to obtain the error rate 10-3 is as shown in FIG. Is 0.6
It is 21 dB when, but is improved to 19 dB when 0.3. Here, the modulation method is π / 4 shift QPSK
(Roll-off rate = 0.5), delay spread is 100n
s, and the transmission rate was 384 kbps. As described above, in the diversity receiver of the present invention, if the correlation coefficient between the diversity antennas can be reduced, high-quality transmission with a small error rate can be performed. The maximum ratio combining is more effective than the selective combining in improving the error rate due to the smaller correlation coefficient.

FIG. 2 is a diagram showing the relationship between the road and the antenna position of the diversity receiver in another embodiment of the present invention. The straight line 13 obtained by projecting the straight line connecting the feeding point 11 of the antenna A and the feeding point 12 of the antenna B on the road surface 19 with the antenna A and the antenna B installed on the road 17 is the width of the road 17. An angle α16 is formed with respect to a straight line 15 on the road surface perpendicular to the direction 20. 1
8 is a building, and the distance between the feeding point 11 of the antenna A and the feeding point 12 of the antenna B is d14. Feeding point 11 of antenna A
The respective heights of the feeding point 12 of the antenna B and the road surface 19 from the road surface 19 may be different or the same. The feature of this embodiment is that the feeding point 11 of the antenna A and the feeding point 12 of the antenna B are
The angle α16 formed by projecting a straight line connecting the two to the road surface 19 and a straight line 15 on the road surface perpendicular to the width direction 20 of the road 17 is 55 ° ≦ α ≦ 65 ° or 25 °. The diversity receiver antenna is arranged so that ≦ α ≦ 35 °. Even when the diversity receiver is installed at a position other than such a road intersection, the correlation coefficient with respect to the antenna interval can be reduced, and the diversity effect is enhanced.

FIG. 3 is a diagram showing the relationship between the road and the antenna position of the diversity receiver in another embodiment of the present invention. A straight line obtained by installing a diversity receiver having an antenna A and an antenna B at a corner 31 of the road and projecting a straight line connecting the feeding point 11 of the antenna A and the feeding point 12 of the antenna B onto the road surface 19 Reference numeral 13 forms an angle α16 with respect to a straight line 15 on the road surface perpendicular to one width direction 20 of the plurality of roads forming a corner. 18 is a building, and the distance between the feeding point 11 of the antenna A and the feeding point 12 of the antenna B is d14. The feature of this embodiment is that the feeding point 11 of the antenna A and the feeding point 12 of the antenna B are
An angle α1 formed by a straight line 13 obtained by projecting a straight line connecting the two on the road surface 19 and a straight line 15 on the road surface perpendicular to the width direction 20 of an arbitrary portion of the road 17 having a turning angle
6 is 55 ° ≦ α ≦ 65 ° or 25 ° ≦ α ≦ 35 °
The diversity receiver antenna is placed so that Thus, even when the base station antenna is installed at a corner of a road, the correlation coefficient between the diversity antennas can be reduced and high quality transmission can be performed by the same principle as that of the embodiment of FIG. You can

FIG. 4 is a diagram showing the relationship between the road and the antenna position of the diversity receiver in another embodiment of the present invention. A diversity receiver having an antenna A and an antenna B is installed on a road 17 having an arbitrary shape, and
An intersection of a curve 41 representing the shape of the end of the road 17 and a straight line 13 obtained by projecting a straight line connecting the feeding point 11 of the antenna A and the feeding point 12 of the antenna B onto the road surface 19 is defined as a point p42. Then, the feeding point 1 for antennas A and B
The straight line 13 obtained by projecting the straight line connecting 1 and 12 onto the road surface 19 and the tangent line 43 at the point p42 on the curve 41 form an angle α16. 18 is a building, and the distance between the feeding point 11 of antenna A and the feeding point 12 of antenna B is d
It is 14. The feature of this embodiment is that the feeding point 1 of the antenna A is
The angle α16 formed by the line 13 obtained by projecting a straight line connecting 1 and the feeding point 12 of the antenna B onto the road surface 19 and the tangent line 42 at the point p42 on the curve 41 is 55 ° ≦ α
The diversity receiver antenna is arranged so that ≦ 65 ° or 25 ° ≦ α ≦ 35 °. As described above, even when the base station antenna is installed on a road having an arbitrary shape, the correlation coefficient between the diversity antennas can be reduced by the same principle as that of the embodiment described in FIG. Quality transmission can be performed.

FIG. 8 is a diagram showing a diversity receiver according to another embodiment of the present invention. (A) is a perspective view,
(B) shows a top view. The antenna A81 and the antenna B82 are installed in the housing 84, and a straight line connecting the feeding point 11 of the antenna A and the feeding point 12 of the antenna B is connected to the housing 8
The straight line 83 obtained by projecting on the bottom surface of 4 forms an angle α16 with the straight line 85 on the bottom surface of the housing parallel to the side surface of the housing 84. The feature of this embodiment is that a straight line 83 obtained by projecting a straight line connecting the feeding point 11 of the antenna A and the feeding point 12 of the antenna B onto the bottom surface of the housing 84 and the side surface of the housing 84 are parallel to each other. The angle α16 formed by the straight line 85 is 55 ° ≦ α ≦ 65 ° or 25 ° ≦
The diversity receiver antenna is arranged so that α ≦ 35 °. Normally, the diversity receiver installed on the road is installed so that the side surface of the housing is parallel to a straight line perpendicular to the width direction of the road. Therefore, as shown in FIG. 8, the angle formed by the arrangement directions of the feeding point 11 of the antenna A and the feeding point 12 of the antenna B is equal to
55 ° ≦ α ≦ 65 ° or 25 ° ≦ with respect to the side surface of 4
By arranging the diversity receiver antennas so that α ≦ 35 °, the correlation coefficient between the diversity antennas can be reduced by the same principle as in the embodiment of FIG.
High quality transmission can be performed.

FIG. 9 is a diagram showing a positional relationship between a road and a diversity receiver in another embodiment of the present invention. A diversity receiver having an antenna A and an antenna B is installed on the road 17, and the diversity receiver housing 8 is installed.
The side surface 91 of any one of 4 and the straight line 15 on the road surface perpendicular to the width direction 20 of the road 17 are parallel to each other. Therefore, feeding point 11 of antenna A and feeding point 1 of antenna B
The angle α16 formed by projecting a straight line connecting two onto the road surface 19 and a straight line 15 on the road surface perpendicular to the width direction 20 of the road 17 is 55 ° ≦ α ≦ 65 ° or 25 ° It becomes ° ≦ α ≦ 35 °. 18 is a building, and the distance between the feeding point 11 of antenna A and the feeding point 12 of antenna B is d
It is 14. The feature of this embodiment is that one of the side surfaces 91 of the housing 84 of the diversity receiver and the width direction 2 of the road 17.
The diversity receiver is installed so that the straight line 15 on the road surface perpendicular to 0 is parallel to the straight line 15. As described above, even when the diversity receiver is installed on the road, the correlation coefficient with respect to the antenna interval can be reduced and high quality transmission can be performed by the same principle as that of the embodiment described in FIG. it can.

[0027]

According to the present invention, the angle α formed by projecting a straight line connecting the feeding points of the diversity antenna onto the road surface with respect to a straight line perpendicular to the width direction of the road is: 55 ° ≦ α ≦ 65 ° or 25 ° ≦ α ≦ 3
By arranging the plurality of antennas at 5 °, the correlation coefficient between the diversity antennas can be reduced even when the base station antenna is installed along the road. As a result, high quality transmission is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a diversity receiver according to the present invention.

FIG. 2 is a diagram showing another embodiment of the diversity receiver according to the present invention.

FIG. 3 is a diagram showing another embodiment of the diversity receiver according to the present invention.

FIG. 4 is a diagram showing another embodiment of the diversity receiver according to the present invention.

FIG. 5 is a top view (a) and a cross-sectional view showing the positional relationship between the direction of the current component contributing to the radiation induced in the antenna and the ground.
(b).

FIG. 6 is a top view (a) and a cross-sectional view showing the positional relationship between the direction of the current component contributing to the radiation induced in the antenna and the ground.
(b).

FIG. 7 is a top view (a) and a cross-sectional view showing the positional relationship between the direction of the current component contributing to the radiation induced in the antenna and the ground.
(b).

FIG. 8 is a perspective view (a) and a top view (b) showing another embodiment of the diversity receiver according to the present invention.

FIG. 9 is a diagram showing another embodiment of the diversity receiver according to the present invention.

FIG. 10 is a diagram showing a conventional multi-wave arrival model between a mobile station and a base station.

FIG. 11 is a diagram showing how multiple waves arrive when multiple waves arrive from four directions (a) and two directions (b) for explaining the present invention.

FIG. 12 is an antenna interval of the correlation coefficient when the arrival angle of the arrival wave A is 90 ° (a), 60 ° (b), 45 ° (c), 30 ° (d) for explaining the present invention. A characteristic diagram showing dependence.

FIG. 13 is a characteristic diagram showing the relationship between the standard deviation of the level distribution of the incoming wave and the correlation coefficient.

FIG. 14 is a characteristic diagram showing a relationship between a correlation coefficient and an error rate.

[Explanation of symbols]

11 ... Feed point of antenna A, 12 ... Feed point of antenna B, 13 ... Straight line connecting the feed point of antenna A and the feed point of antenna B on the road surface, 1
4 ... Antenna spacing d, 15 ... Straight line perpendicular to width direction of road, 16 ... Angle α, 17 ... Road, 18 ... Building, 19
… Road surface, 20… Road width direction, 21… Road intersection, 3
1 ... Curve of road, 41 ... Curve representing shape of end of road, 42 ... Straight line obtained by projecting straight line connecting feed point of antenna A and feed point of antenna B on road surface and shape of road edge , Tangent to point p, 43 ... Direction of current component contributing to radiation induced in antenna A, 52 ... Direction of current component contributing to radiation induced in antenna B, 81 ... Antenna A, 82 ... Antenna B, 83 ... Straight line obtained by projecting a straight line connecting the feeding point of the antenna A and the feeding point of the antenna B on the bottom surface of the housing, 84 ... Housing, 85 ... On the side surface of the housing Parallel straight lines, 91 ... Side surface of housing, 101 ... Mobile station, 102 ... 2
Circle of radius r representing the next wave source, 111 ... Arrival wave A, 112
... incoming wave B, 113 ... incoming wave C, 114 ... incoming wave D

Claims (33)

[Claims] 1. An antenna A and an antenna B, in which a feeding point of the antenna A and a feeding point of the antenna B are separated by a distance d, are installed at an intersection of roads, and one of the intersecting roads is An angle α formed by a straight line on the road surface perpendicular to the width direction and a straight line connecting the feeding point of the antenna A and the feeding point of the antenna B on the road surface is 55.
A diversity receiver characterized in that ° ≦ α ≦ 65 °. 2. The diversity receiver according to claim 1, wherein the angle α is 60 °. 3. An antenna A and an antenna B, in which a feeding point of the antenna A and a feeding point of the antenna B are separated by a distance d, are installed at an intersection of roads, and one of the intersecting roads is An angle α between a straight line on the road surface perpendicular to the width direction and a straight line connecting the feeding point of the antenna A and the feeding point of the antenna B to the road surface is 25.
A diversity receiver characterized in that ° ≦ α ≦ 35 °. 4. The diversity receiver according to claim 3, wherein the angle α is 30 °. 5. A straight line on a road surface in which an antenna A and an antenna B are installed on a road and the feeding point of the antenna A and the feeding point of the antenna B are separated by a distance d, and which is perpendicular to the width direction of the road. And the angle α formed by projecting a straight line connecting the feeding point of the antenna A and the feeding point of the antenna B onto the road surface is 55 ° ≦ α ≦ 65 °. . 6. The diversity receiver according to claim 5, wherein the angle α is 60 °. 7. A straight line on a road surface in which an antenna A and an antenna B are installed on a road, and the feeding point of the antenna A and the feeding point of the antenna B are separated by a distance d, and which is perpendicular to the width direction of the road. And an angle α formed by projecting a straight line connecting the feeding point of the antenna A and the feeding point of the antenna B onto the road surface is 25 ° ≦ α ≦ 35 °. . 8. The diversity receiver according to claim 7, wherein the angle α is 30 °. 9. An antenna A and an antenna B, wherein the feeding point of the antenna A and the feeding point of the antenna B are separated by a distance d, are installed at a corner of a road, and the width of any of a plurality of roads forming the corner. The angle α formed by projecting the straight line on the road surface perpendicular to the direction and the straight line connecting the feeding point of the antenna A and the feeding point of the antenna B onto the road surface is 55 ° ≦ α ≦ 65 ° A diversity receiver characterized by: 10. The diversity receiver according to claim 9, wherein the angle α is 60 °. 11. An antenna A and an antenna B, wherein the feeding point of the antenna A and the feeding point of the antenna B are separated by a distance d, are installed at a corner of a road, and any width of a plurality of roads forming the corner. The angle α formed by the straight line on the road surface perpendicular to the direction and the straight line obtained by projecting the straight line connecting the feeding point of the antenna A and the feeding point of the antenna B on the road surface is 25 ° ≦ α ≦ 35 ° A diversity receiver characterized by: 12. The diversity receiver according to claim 11, wherein the angle α is 30 °. 13. A curve representing the shape of the end of the road where antenna A and antenna B are installed on a road having an arbitrary shape, and the feeding point of antenna A and the feeding point of antenna B are separated by a distance d. And a straight line connecting the feeding point of the antenna A and the feeding point of the antenna B with the straight line obtained by projecting on the road surface is defined as a point p, at a point p on the curve representing the shape of the end of the road. Diversity reception characterized in that an angle α formed by projecting a tangent line and a straight line connecting the feeding point of the antenna A and the feeding point of the antenna B on the road surface is 55 ° ≦ α ≦ 65 ° Machine. 14. The diversity receiver according to claim 13, wherein the angle α is 60 °. 15. A curve representing the shape of the end of the road where the antenna A and the antenna B are installed on a road having an arbitrary shape, and the feeding point of the antenna A and the feeding point of the antenna B are separated by a distance d. And a straight line connecting the feeding point of the antenna A and the feeding point of the antenna B with the straight line obtained by projecting on the road surface is defined as a point p, at a point p on the curve representing the shape of the end of the road. Diversity reception characterized in that an angle α formed by projecting a tangent line and a straight line connecting the feeding point of the antenna A and the feeding point of the antenna B onto the road surface is 25 ° ≦ α ≦ 35 ° Machine. 16. The diversity receiver according to claim 15, wherein the angle α is 30 °. 17. The antenna A and the antenna B are arranged such that the directions of the current components contributing to the radiation induced in the antenna A and the antenna B are perpendicular to the road surface, respectively. 17. The diversity receiver according to any one of 1 to 16. 18. An antenna A and an antenna B so that the directions of current components contributing to the radiation induced in the antenna A and the antenna B are parallel to the road surface and perpendicular to the width direction of the road. The diversity receiver according to any one of claims 1 to 16, further comprising: 19. The antenna A and the antenna B are arranged such that the directions of the current components contributing to the radiation induced in the antenna A and the antenna B are parallel to the road surface and parallel to the width direction of the road. The diversity receiver according to any one of claims 1 to 16, further comprising: 20. A bottom surface of a housing, the housing having the antenna A and the antenna B in which a feeding point of the antenna A and a feeding point of the antenna B are separated from each other by a distance d, and being parallel to any one side surface of the housing. The angle α between the above straight line and the straight line obtained by projecting the straight line connecting the feeding point of the antenna A and the feeding point of the antenna B on the bottom surface of the housing is 55 ° ≦ α ≦ 65 °. Characteristic diversity receiver. 21. The diversity receiver according to claim 20, wherein the angle α is 60 °. 22. A bottom surface of a housing which has a housing having antennas A and B with a feeding point of antenna A and a feeding point of antenna B being separated by a distance d, and which is parallel to any one side surface of the housing. The angle α between the above straight line and the straight line obtained by projecting the straight line connecting the feeding point of the antenna A and the feeding point of the antenna B on the bottom surface of the housing is 25 ° ≦ α ≦ 35 °. Characteristic diversity receiver. 23. The diversity receiver according to claim 22, wherein the angle α is 30 °. 24. The side surface of the housing of the diversity receiver according to any one of claims 20 to 23 and the straight line on the road surface perpendicular to the width direction of the road are parallel to each other.
A method for installing a diversity receiver, characterized in that the described diversity receiver is installed. 25. The antenna spacing d is λ / 4 <d <5λ
(Λ: wavelength)
The diversity receiver according to any one of 1. 26. The diversity receiver according to claim 1, wherein the antenna A is a monopole antenna. 27. The diversity receiver according to claim 1, wherein the antenna A is a dipole antenna. 28. The diversity receiver according to claim 1, wherein the antenna A is a microstrip antenna. 29. The diversity receiver according to claim 1, wherein the antenna A is a slot antenna. 30. The diversity receiver according to claim 1, wherein the antenna B is a monopole antenna. 31. The diversity receiver according to claim 1, wherein the antenna B is a dipole antenna. 32. The diversity receiver according to claim 1, wherein the antenna B is a microstrip antenna. 33. The diversity receiver according to claim 1, wherein the antenna B is a slot antenna.