JPH104313A - Antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain stable and high quality radio relay even in a channel or a tunnel and to make the size small and the weight light. SOLUTION: The system is provided with reception antennas 21, 23, a transmission antenna 22, and a height adjustment device 28 consisting of an antenna mount plate 24, a spherical seat 25 to adjust the height of the transmission antenna 22, an adjustment bolt 26 and a guide 27. The reception antenna 21 and the transmission antenna 22 are made up of a 2-element right-handed rotatory polarized wave microstrip path element, and the reception antenna 23 is made up of a 2-element left-handed rotatory polarized wave microstrip path element. The reception antennas 21, 23 conduct the circularly polarized wave diversity reception using a right-handed rotatory polarized wave and a left- handed rotatory polarized wave. The reception antennas 21, 23 and the transmission antenna 22 are directly mounted on the antenna mount plate 24 at an interval of 1λ respectively. The transmission antenna 22 is mounted by a height of about 1/4λ via the height adjustment device 28. Furthermore, a feeding connector 29 is provided to the reception antennas 21, 23 and the transmission antenna 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device used for a radio relay device in an environment where walls such as a headrace and a tunnel are surrounded by walls.

[0002]

2. Description of the Related Art Conventionally, there is a case where it is desired to communicate with the ground in an environment where a water channel, a tunnel and the like are surrounded by a wall surface. The above-mentioned headrace is a tunnel-shaped waterway that draws water for power generation dammed by a dam to the power plant, mainly in a hydroelectric power plant. Normally, the inside of the headrace is filled with water as described above.However, during maintenance and inspection of the headrace, the water in the headrace is drained, and a worker enters the inside to perform maintenance and inspection. It is. During this maintenance work, it is necessary to communicate the status of the maintenance work from the headrace to the ground.

Conventionally, a radio communication system shown in FIG. 11 or a wire communication system using a leaky coaxial line shown in FIG. 12 is used for communication in an environment where the surroundings of a headrace, a tunnel and the like are surrounded by a wall surface. Have been.

In FIGS. 11 and 12, reference numeral 11 denotes a headrace (or tunnel), reference numeral 12 denotes a fixed station device provided on the ground, reference numeral 13 denotes a fixed station transmitting / receiving antenna provided in the headrace 11, and reference numeral 14 denotes a headrace. The leaky coaxial line installed in 11 and 18 are mobile devices.

When the maintenance of the headrace 11 is performed, an operator enters the headrace 11 with the mobile unit 18,
Communication is performed with the fixed station device 12 on the ground via the fixed station transmitting / receiving antenna 13 or the leaky coaxial line 14.

However, in an environment in which the surroundings of a headrace, a tunnel, etc. are surrounded by a wall surface, propagation loss and fluctuations in short-term reception level are larger than in free space, and the communication using radio shown in FIG. Satisfactory performance cannot be obtained in terms of propagation distance and stability, and the leaky coaxial line 14 shown in FIG.
In the wired system according to the above, laying and collecting the leaky coaxial line 14 requires a great deal of cost and labor. Also, in the event of an emergency disaster in the headrace tunnel or tunnel pit, there is no effective way to contact the ground.

In recent years, a wireless relay system shown in FIG. 1 has been researched and developed in order to solve the above problems. FIG.
, 15a, 15b,... Are a plurality of wireless repeaters installed at predetermined intervals in the headrace 11 and each include a relay antenna device 16 and a mobile antenna 17;
Radio repeater 15a installed near the entrance of waterway 11
Are connected to a fixed station device 12 on the ground via a cable 19. The wireless repeaters 15a, 15b,..., The relay antenna device 16, and the mobile device antenna 17 are integrated to form a wireless repeater, and the worker carries the wireless repeater when performing maintenance and inspection. The wireless relay system is constructed by sequentially installing the wireless relay system in the headrace 11.

Then, each of the above-mentioned wireless repeaters 15a, 15
Between b,..., signals are transmitted and received wirelessly via the relay antenna device 16, and the wireless repeaters 15 a, 15 a
, and the mobile device 18, the antenna 17 for the mobile device.
The transmission and reception of signals are performed by That is, the signal transmitted from the fixed station device 12 is transmitted to the plurality of wireless repeaters 15.
, 15b,... and the relay antenna device 16 are relayed in the water channel 11 and transmitted to the mobile device 18 via the mobile device antenna 17. Further, the signal emitted from the mobile device 18 is sent to the fixed station device 12 through a route reverse to the above case.

[0009]

In the above-described wireless relay system, when a worker carries out maintenance and inspection, the wireless relay device is carried and sequentially installed in the water conduit 11, so that the wireless relay device, particularly the relay device, is used. Antenna device 16 is small and lightweight,
In addition, it is a requirement that stable and high-quality wireless relay can be performed. Stable and high quality wireless relay means that there is little variation in the headrace, the location in the tunnel, and the temporal reception level. Propagation loss in headraces and tunnels is also an important factor. That is, the smaller the propagation loss, the longer the relayable distance becomes, and the total number of wireless relay devices can be reduced. This leads to cost reduction of the entire wireless relay system.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a small and lightweight antenna device capable of performing stable and high-quality wireless relay even in a headrace or a tunnel. The purpose is to:

[0011]

According to the present invention, there is provided an antenna device for a radio repeater, comprising a right-handed circularly polarized microstrip patch element and a left-handed circularly polarized microstrip patch element provided on a substrate. A reception antenna for performing polarization diversity reception, and a transmission antenna including a circularly polarized microstrip patch element disposed at a different height from the reception antenna on the substrate. I do.

The present invention also provides an antenna device for a radio repeater, comprising a right-handed circularly polarized microstrip patch element and a left-handed circularly polarized microstrip patch element provided on a substrate, and receiving circularly polarized diversity reception. And a transmitting antenna comprising a circularly polarized microstrip patch element provided on the substrate, and the transmitting antenna held at a different height from the receiving antenna, and the height A height adjusting mechanism having a function of adjusting the position.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 2A and 2B are diagrams showing a configuration of an antenna device according to an embodiment of the present invention, wherein FIG.
(B) is a side view. As shown in FIG. 2, the antenna device according to the present embodiment includes a receiving antenna 21, a transmitting antenna 22, a receiving antenna 23, and an antenna mounting plate 2.
And a height adjustment mechanism 28 including a ball seat 25, an adjustment bolt 26, and a guide 27 for adjusting the amount of antenna coupling according to the height of the transmission antenna 22.

The receiving antenna 21 and the transmitting antenna 22 are constituted by two-element right-handed circularly polarized microstrip patch elements, and the receiving antenna 23 is constituted by two-element left-handed polarized microstrip patch elements. I have. The receiving antennas 21 and 23 perform circularly-polarized diversity reception using right-handed and left-handed circularly polarized waves.

The receiving antennas 21 and 23 and the transmitting antenna 22 are arranged at an interval of 1λ respectively.
, And the transmitting antenna 22 is attached at a height of about λλ via a height adjusting mechanism 28 to constitute one antenna device. Each of the receiving antennas 21 and 23 and the transmitting antenna 22 is provided with a power supply connector 29 so that independent input and output can be performed. One or two of the antenna devices are mounted on the mounting base 30 together with one or two transmitters and receivers to constitute a wireless relay device.

FIGS. 3A and 3B are side views showing a detailed configuration example of the height adjusting mechanism 28. FIG. The transmitting antenna 22 is mounted on the antenna mounting plate 24 via the ball seat 25 and the adjustment bolt 26. The adjusting bolt 26 is threaded for height adjustment and fixing, and the height of the transmitting antenna 22 can be changed by rotating one of the adjusting bolt 26 and the fixing nut 31. A guide 27 is provided on the transmitting antenna 22 to prevent the antenna from tilting.

Since the optimum height of the antenna is determined by the frequency, even if the height adjustment mechanism 28 is omitted and the antenna height is fixed, the frequency can be variably adjusted to set the optimum conditions. can do.

Next, the operation and effect of the antenna device will be described. In the antenna device according to the present embodiment, the frequency band is, for example, 5 to 6 GHz. From the frequency characteristics of the headrace shown in FIG. 4, in radio wave propagation in the headrace, as the frequency decreases, the propagation loss tends to increase, and the propagation distance of the radio wave decreases. On the other hand, the short-term level fluctuation indicating the stability of the reception level tends to increase as the frequency increases. Therefore, when the frequency is low, a predetermined propagation distance cannot be secured, so that the number of relays increases and the cost increases, which is not practical. When the frequency is high, the propagation distance can be secured, but the level fluctuation is large, so that the stability and reliability of the wireless relay system are reduced due to the instantaneous interruption and fading of the relay line, which is not practical. The frequency in the 5 to 6 GHz band used in the antenna device according to the present embodiment is most suitable for wireless relay in an area surrounded by walls such as a headrace or a tunnel, and a highly reliable wireless relay system is constructed. It is possible to do.

In the antenna device according to the present embodiment, the antenna type is a microstrip patch antenna. The microstrip patch antenna is formed on a printed board by photoetching or the like.
For this reason, the microstrip patch antenna can realize a very low profile and thin antenna.

In the present embodiment, the receiving antenna 21,
23. The transmitting antenna 22 is a two-element microstrip patch antenna in which, for example, a microstrip patch element is photo-etched on a printed circuit board having a thickness of 0.03λ together with a microstrip line connecting these elements. . The thickness of the microstrip patch antenna thus configured is about 0.1 including the thickness of the base plate for holding the printed circuit board.
It is about 5λ, and it is possible to reduce the thickness.

The shape of the microstrip patch element is not a simple circle, but a circularly polarized wave is generated by partially deforming the element. To generate a circularly polarized wave with a microstrip patch antenna, a two-power splitter, 90
In general, a phase shifter is used to feed two orthogonal points of a microstrip patch element. FIG. 2 shows a method of providing a notch as an example of the generation of circularly polarized waves. In addition, the turning direction of the polarization can be realized by the direction of the notch with respect to the feeding point. In FIG. 2, the receiving antenna 21 and the transmitting antenna 22 generate right-handed polarization, and the receiving antenna 23 generates left-handed polarization. I have. As a result, in this embodiment, a power divider, a 90 ° phase shifter, and the like are not required at all, which contributes to cost reduction.

Furthermore, a linear antenna typified by a dipole antenna with a reflector having substantially the same performance requires a balun-like balanced-unbalanced conversion circuit when matching with a coaxial line. The antenna has a feature that this balanced-unbalanced conversion circuit is not required, which also contributes to a reduction in the cost of the antenna device.

Next, circular polarization diversity reception will be described. In an environment where a water channel, a tunnel, or the like is surrounded by a wall, a method of performing stable communication using circularly polarized waves is an effective means.
It has already been reported in JP-A-7-9259.

In the mobile radio communication on the ground,
Since there is a reflected wave from a building or the like and the communication quality is impaired, it is general to improve the quality by diversity reception. In mobile radio communication on the ground, good reception is performed by a space diversity system in which a plurality of vertically polarized antennas are installed at intervals of about 0.5 to several λ.

However, in an environment in which the circumference of a headrace, a tunnel, or the like is surrounded by a wall surface, the polarization plane easily rotates, so that good reception is hardly expected in the space diversity system. In addition, the polarization diversity system using linearly polarized waves of vertical polarization and horizontal polarization has little effect because the propagation itself in linear polarization lacks stability.

FIGS. 5A and 5B show propagation characteristics of linearly polarized waves in the headrace. FIG. 5A shows a case where a vertically transmitted radio wave is received by a vertically polarized antenna.
(B) is a measurement example in the case of receiving with a horizontally polarized antenna. At this time, the average value of the Z-transformed correlation coefficient which is a guide for the diversity effect is about 0.5, which is not a good result although the diversity effect is present.

As described above, the antenna device according to the present embodiment implements the circularly polarized diversity reception system using right-handed circularly polarized light and left-handed circularly polarized wave. 6 (a) and 6 (b) show the propagation characteristics of circularly polarized waves in the headrace.

FIG. 6A shows a measurement example when a radio wave transmitted in right-handed circularly polarized wave is received by a right-handed circularly polarized antenna, and FIG. is there. At this time, the average value of the Z-transformed correlation coefficient is about 0.02,
The diversity effect is very large, and it becomes an effective means for wireless relay in an environment surrounded by a wall such as a headrace or a tunnel, and a stable high-quality wireless relay system can be constructed.

Next, the effect when the transmitting antenna and the receiving antenna are separated will be described. FIG. 7A is a system diagram of a general relay device. Antenna sharing device 44
Is for connecting the transmitter 41 and the receiver 42 to one transmission / reception shared antenna 43a, and is composed of a directional coupler and the like.

FIG. 7B is a system diagram when the antennas are separately configured. The transmitter 41 is a transmitting antenna 43
b, and the receiver 42 is directly connected to the receiving antenna 43c by a coaxial cable or the like. By separately configuring the transmitting antenna 43b and the receiving antenna 43c in this manner, an antenna sharing device is not required, the path from the antenna to the transceiver is simplified, and the size and weight can be reduced. Further, since the power supply path is simplified, the loss of the power supply system can be reduced.

FIGS. 8 and 9 show an example of a configuration in which a transmission / reception antenna is separately provided to perform a polarization diversity reception system. 8 (a) and 9 (a) are front views, and FIGS. 8 (b) and 9 (b) are side views.

In FIG. 8, reference numeral 22 denotes a transmitting antenna, 2
1 and 23 are receiving antennas having different polarizations. Also, 29
Is a power supply connector. A receiving antenna 21 is provided at the center, and a transmitting antenna 22 and a receiving antenna 23 are arranged on both sides thereof. In this case, the interval between the antennas is set to 2λ or more in order to avoid the occurrence of coupling between the antennas.

On the other hand, in the example shown in FIG. 9, a transmitting antenna 22 is provided in the center, and the receiving antennas 2 are provided on both sides thereof.
1, 23 are arranged. The transmitting antenna 22 is provided with a height adjusting mechanism 28. When the height adjusting mechanism 28 is provided as described above, the coupling between the antennas can be optimized, and the interval between the antennas, that is, the transmitting antenna 4
2 and the receiving antennas 41 and 43 can be set to about 1λ. On the other hand, receiving antennas 21 and 23
Is secured at 2λ, so that a predetermined coupling amount can be secured without providing a height adjusting mechanism.

When the structure around the transmitting antenna 22 is asymmetric as shown in FIG. 8, the directional characteristics of the transmitting antenna 22 become asymmetric due to the influence of the surrounding structure, or the main beam is not affected. Although the direction is deflected, by arranging the transmitting antenna 22 at the center as in the example of FIG. 9, the influence of the surrounding structures can be prevented.

Next, a method of optimizing the coupling amount between the transmitting and receiving antennas will be described. When the transmitting antenna and the receiving antenna are arranged close to each other, coupling occurs between the antennas,
Radio waves radiated from the transmitting antenna are directly received by the receiving antenna, which adversely affects wireless relay. This coupling changes depending on the phase difference between the antennas, and takes a minimum value when the phase difference is λ / 4.

FIG. 10 shows a change in the coupling amount when the phase difference between the antennas is changed. Changing the phase difference between the antennas can be realized by changing the distance between the antennas.

The distance between the antennas is generally changed in a direction orthogonal to the radiation axis of the radio wave, but at the same time requires a large space. In this embodiment, the same effect is obtained by changing the distance in a direction parallel to the radiation axis. Furthermore, since the coupling amount changes depending on the frequency used, the coupling amount can be optimized by providing the height adjustment mechanism 28.

[0038]

As described above in detail, according to the present invention, stable and high-quality radio relay can be performed in an environment in which a water channel, a tunnel, or the like is surrounded by a wall surface, and small and light. It is possible to provide an antenna device which can be configured at a low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a wireless relay system in a headrace and a tunnel to which the present invention is applied.

FIG. 2 is a diagram showing a configuration of an antenna device according to one embodiment of the present invention.

FIG. 3 is a side view showing details of a height adjusting mechanism in the embodiment.

FIG. 4 is a diagram showing the frequency characteristics of propagation loss and short-term level fluctuation in circularly polarized waves in a headrace and a tunnel.

FIG. 5 is a diagram showing electric field strength distance characteristics in linearly polarized waves in a headrace and a tunnel.

FIG. 6 is a diagram showing electric field strength distance characteristics in circularly polarized waves in a headrace and a tunnel.

FIG. 7 is a system diagram showing a schematic configuration of a relay device.

FIG. 8 is a diagram showing a configuration example when a polarization diversity reception method is performed.

FIG. 9 is a diagram showing another configuration example when the polarization diversity reception system is performed.

FIG. 10 is a diagram illustrating a change in a coupling amount when a phase difference between antennas is changed.

FIG. 11 is a diagram showing a conventional radio relay system in a headrace and a tunnel.

FIG. 12 is a diagram showing a conventional relay system using a leaky coaxial line in a headrace and a tunnel.

[Explanation of symbols]

 21, 23 Receiving antenna 22 Receiving antenna 24 Antenna mounting plate 25 Ball base 26 Adjusting bolt 27 Guide 28 Height adjusting mechanism 29 Power supply connector 30 Mounting frame 31 Fixed nut 41 Transmitter 42 Receiver 43a Transmitting and receiving antenna 43b Transmitting antenna 43c Receiving antenna

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Takao Shibuya 2-9-19-1 Minatomachi, Aomori City, Aomori Prefecture Tohoku Electric Power Co., Inc.Aomori Branch (72) Inventor Hiroshi Kasahara 1406 Hasunuma, Omiya City, Saitama Prefecture Yagi antenna stock (72) Inventor Hiroshi Saeki 1406 Hasunuma, Omiya City, Saitama Prefecture Yagi Antenna Yomi Antenna Co., Ltd.

Claims (5)

[Claims] 1. An antenna device for a wireless relay device, comprising: a right-handed circularly polarized microstrip patch element and a left-handed circularly polarized microstrip patch element provided on a substrate, for receiving circularly polarized wave diversity. An antenna device comprising: an antenna; and a transmitting antenna including a circularly polarized microstrip patch element disposed on the substrate at a position different in height from the receiving antenna. 2. An antenna device for a radio repeater, comprising: a right-handed circularly polarized microstrip patch element and a left-handed circularly polarized microstrip patch element provided on a substrate, for receiving circularly polarized diversity reception. An antenna, a transmitting antenna comprising a circularly polarized microstrip patch element provided on the substrate, and a transmitting antenna held at a different height from the receiving antenna and the height adjusted. An antenna device comprising a height adjusting mechanism having a function. 3. The antenna device according to claim 1, wherein the operating frequencies of the receiving antenna and the transmitting antenna are set in a 5 to 6 GHz band. 4. The antenna device according to claim 1, wherein a transmitting antenna is arranged between the right-handed circularly polarized light element and the left-handed circularly polarized light element of the receiving antenna. 5. A transmitting antenna is disposed on one side, and a right-handed circularly polarized element and a left-handed circularly polarized element of the receiving antenna are disposed on the center and the other side. The antenna device according to claim 1.