JPH06200584A - Electric wave reflector - Google Patents

Abstract

PURPOSE:To provide an electric wave reflector of good appearance having master and slave transceivers, while eliminating the need of a wiring work for a ceiling, by forming the reflector to have the surface of convex or concave curvature, and mounting the reflector on a ceiling for reflecting electric waves from the master or slave transceiver to the slave or master transceiver. CONSTITUTION:An electric wave reflector 1A is formed to have a shape with a spherical form drawing process applied to a flat wave reflective material such as copper and aluminum, and mounted on the side of a ceiling C. Then, electric waves from master or slave equipment are reflected over the predetermined divergent range, thereby enabling local radio wave information transmission to be practically undertaken. In this case, the antennas of the master and slave equipment are so installed as to be directed toward the reflector 1A. Consequently, communication between both equipment is made via the reflector 1A. According to this construction, a wiring work for the ceiling C related to the master equipment can be eliminated, and the installation of non- directional radio equipment is not required. Thus, a change in layout can also be easily coped with at low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave reflection plate, and more particularly to a radio wave reflection plate suitable for a local area LAN or an indoor LAN.

[0002]

2. Description of the Related Art Conventionally, a local information communication system typified by a LAN is used to construct a network by using a large computer, a personal computer, a workstation, etc., and perform information processing and data sharing. Downsizing, high performance,
The market has been expanding rapidly with the advancement of communication functions. As the network portion, conventionally, a cable line such as a coaxial cable or a twisted pair cable has been used. Therefore, LA
With the spread of N, there is a danger that the office will be flooded with wiring,
Every time the layout is changed, it is necessary to carry out work such as rewiring, so that it is required to be wireless. From the above background, wireless LAN
Devices for (in-house wireless communication) are being developed, but these are generally as follows. First
Method (hereinafter referred to as "type A"), frequency 100 ~
Transmission speed of 5 using 900MHz (megahertz) band
At 250 Kbps, an omnidirectional communication type antenna is used. The second method (hereinafter referred to as "type B") uses the frequency of 2.4 GHz (gigahertz) band, uses the SS (spread spectrum) method at the transmission rate of 2 to 4 Mbps, and uses the omnidirectional communication type antenna. . The third method (hereinafter referred to as “type C”) is a method as shown in FIG. 11, which uses a quasi-millimeter wave frequency of 19 GHz and a transmission rate of 10 Mbps and an antenna directivity of 60.
The omnidirectional communication is performed in a degree x 6 sector, and the strongest radio wave is received from this. The fourth method (hereinafter referred to as "type D") is a millimeter wave band frequency (30 to
300 GHz) and transmission speed is 10 to 100 Mbps
Although this method has not been put on the market yet, the idea is to use an omnidirectional antenna for a wireless device (hereinafter referred to as “main device”) 22 that connects to an existing network such as an indoor side, and an information processing terminal side. Wireless device (hereinafter referred to as "child device") 23
A directional flat antenna or a horn antenna is used for (see FIG. 12).

[0003]

However, considering the types C and D, which have a transmission speed of 10 Mbps or more, among the above-mentioned conventional systems, the type C has a complicated system and becomes costly, and thus, it opposes the wired system. However, the type D has drawbacks such as the need for wiring work on the ceiling and the poor appearance. The present invention has been made to solve the above problems, and an object of the present invention is to provide a radio wave reflector that does not require ceiling wiring work and has a good appearance.

[0004]

In order to solve the above problems, a radio wave reflector according to the present invention is a radio wave reflector used in a local information communication system including a master transceiver and a slave transceiver, It has a convex curved surface or a concave curved surface, and is attached to the ceiling part of the premises, and is configured to reflect radio waves from the parent transceiver or the child transceiver toward the child transceiver or the parent transceiver.

[0005]

According to the present invention having the above-mentioned structure, since it is only necessary to attach the radio wave reflector to the ceiling portion, the ceiling wiring work relating to the master unit is unnecessary, and the radio wave reflection / diffusion effect is excellent. The radio does not need to be provided with a high-priced omnidirectional radio, and the radio wave reflector can be easily attached and detached, so that the layout can be easily changed at low cost.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of the first embodiment of the present invention. Further, FIG. 2 shows the configuration of the second embodiment of the present invention. As shown in FIG. 1 or 2, this radio wave reflection plate 1A or 1B
Has a shape obtained by adding a diaphragm of a spherical body (convex surface or concave surface) to a flat plate such as copper or aluminum having radio wave reflectivity, and by reflecting the radio wave from the master unit or the slave unit with a specific spread, It enables on-premises wireless information communication.

The protrusion height a or the recess depth b of the spherical body is
In both cases, when the diameter of the sphere is D, it is about D / 8 to D / 6.

3 and 4 show examples of the construction of a local wireless LAN using the radio wave reflection plate 1A or 1B. In this example, a millimeter wave band of 30 GHz or more is used as the frequency band, and it is assumed that the directivity is strong. As shown in the figure, in this indoor wireless LAN system, the information terminal device 10 and its child device 3 are placed on a desk in the room, and the parent device 2 on the network connection side is placed at an appropriate position such as a wall surface or a desk in the room. The radio wave reflection plate 1 (1A or 1B) is attached to the ceiling C side of the room. In this case, the antennas of the master unit 2 and the slave unit 3 are
It is installed in the direction of the radio wave reflection plate 1. Therefore,
Communication between the master unit 2 and the slave unit 3 is performed via the radio wave reflection plate 1.

FIG. 4 is a diagram showing a connection example of each device in the above-mentioned indoor wireless LAN. As shown in the figure, the base unit side is connected to the Ethernet (including other networks such as FDDI, token ring, etc.) by a wired line L, and the base unit side wireless transceiver 2 is directed toward the radio wave reflection plate 1. .
On the other hand, the wireless transmitter / receiver 3 on the slave side is also directed toward the radio wave reflection plate 1, and each information terminal (personal computer 7, etc.)
Are wirelessly connected by radio wave W.
AN is realized. In this configuration, the base unit side does not necessarily have to be connected to the wired LAN, and can be used in other applications such as being used as a printer buffer for the printer 8 of the computer.

Next, the radio wave reflection plates 1A and 1 of the present embodiment.
The reflection of the radio wave W at B is shown in FIGS. As can be seen from the figure, the radio wave W is reflected with a specific spread by the radio wave reflection plate. Due to the spread of this radio wave, transmission / reception between the master unit and the slave unit becomes possible.

Radio waves in the millimeter wave band have strong directivity, and
The spread of the radio wave when used for N is about 1 in terms of angle.
It is around 0 degrees. As shown in FIG. 9 and Table 1, when the radio wave W emitted from the transmitter 2 on the desk right above the ceiling C has a height h to the ceiling C of 2 m according to the height h to the ceiling C. Has a diameter of about 35 at the point of incidence on the radio wave reflector 1.
When the height to the ceiling C is 3 m, the diameter is about 52 cm at the point of incidence on the radio wave reflection plate 1. Then, it is reflected by the radio wave reflection plate 1 (1A or 1B) immediately above, and reaches the receiver with a predetermined spread according to the height h to the ceiling C. in this case,
The arriving radio wave W has a different spread D2 depending on the spherical diameter D1 of the radio wave reflector 1 (see Table 1).

[0012]

[Table 1]

The spread dimension D2 of the reflected radio wave shown in Table 1 is
If the spherical body of the radio wave reflection plate 1 is convex (in the case of 1A) or concave (in the case of 1B) with respect to the incoming direction of the radio wave W, the height h from the desk to the ceiling C and the required spread It is necessary to select the optimum one in terms of the dimension D2 and the electric field strength of reception of radio waves.

That is, as shown in Table 1, the ceiling height h
When the distance is 2 m, the spherical diameter of the radio wave reflection plate 1 is 60 to 80
It is understood that the appropriate range is about cm, and the spherical diameter of the radio wave reflection plate 1 is about 100 to 130 cm when the ceiling height h is 3 m. This is because when the spherical diameter of the radio wave reflection plate 1 is larger than the ceiling height h, the spread dimension D of the reflected radio wave is D.
2 is too small and the reach of reflected radio waves is too small, so it is not suitable for communication between the master and slave units. On the other hand, if the spherical diameter of the radio wave reflector 1 is smaller than the ceiling height h, This is because the spread dimension D2 is too large and the reach of the reflected radio waves is expanded, but the received electric field strength is too small, and in this case too, it is not suitable for communication between the master unit and the slave unit.

FIG. 10 is a diagram showing the radio wave reflection characteristics when a flat reflector plate is used as the radio wave reflector plate 1. The bottom row of Table 1 shows the case where a flat reflector plate is used as the radio wave reflector plate 1. The spread dimension D2 of the radio wave is shown. As can be seen from the above, when the radio wave reflection plate is flat, the spread of the reflected radio wave W is too small, which is not suitable for communication between a plurality of parent devices and child devices.

Further, since the radio wave reflected by the radio wave reflection plate is diffused in a wide range, the antenna propagation loss becomes larger than that in the case of being reflected by the plane plate. This value is calculated as Γ = 40.23 + 20 logd. In the above equation, Γ is the antenna propagation loss,
d represents the propagation distance, respectively.

For example, the height from the handset to the ceiling is 3 m.
When reflected on a radio wave reflection plate having a diameter of 1 m, d corresponds to 49 m in terms of straight line, and Γ = 74 dB. On the other hand, when a wireless device having a directional flat antenna with an output of 20 mW and 20 dBi in the millimeter wave band is used, d =
Communication over a distance of about 100 m is possible, and Γ at this time is 80 dB. Thus, when applying the above-mentioned radio wave reflector, it is necessary to consider the capability of the radio device.

The present invention is not limited to the above embodiment. The above-mentioned embodiment is an exemplification, has substantially the same configuration as the technical idea described in the scope of the claims of the present invention, and has any similar effect to the present invention. It is included in the technical scope of the invention.

For example, in the above-described embodiment, the radio wave reflector using the convex side or concave side of the spherical surface having a constant curvature as the convex curved surface or the concave curved surface has been described as an example. A convex curved surface or a concave curved surface may be used. For example, the convex side or concave side of the paraboloid of revolution, the convex side or concave side of the spheroidal surface, and the like. In short, any convex curved surface or concave curved surface may be used.

[0020]

As described above, according to the present invention having the above-mentioned structure, it is only necessary to attach the radio wave reflection plate to the ceiling portion, the ceiling wiring work relating to the master unit is unnecessary, and the radio wave reflection / diffusion effect is obtained. Since it is excellent in, it is not necessary to provide a high-priced omnidirectional radio in the radio on the master side, and
Since this radio wave reflector can be easily attached and removed, layout changes can be easily accommodated at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing an overall configuration of a second embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a configuration example of a local area wireless LAN using the radio wave reflection plate shown in FIG. 1 or 2.

FIG. 4 is a connection diagram showing a configuration example of a local area wireless LAN or the like using the radio wave reflection plate shown in FIG. 1 or 2.

5 is a diagram (1) showing a reflection characteristic of a radio wave by the radio wave reflection plate shown in FIG.

6 is a diagram (2) showing a reflection characteristic of a radio wave by the radio wave reflection plate shown in FIG.

7 is a diagram (1) showing a reflection characteristic of a radio wave by the radio wave reflection plate shown in FIG.

8 is a diagram (2) showing a reflection characteristic of a radio wave by the radio wave reflection plate shown in FIG.

FIG. 9 is a diagram for explaining the spread of reflected radio waves when a transmitter is placed directly below the radio wave reflection plate shown in FIG. 1 or FIG. 2 for transmission.

FIG. 10 is a diagram showing radio wave reflection characteristics of a flat radio wave reflection plate.

FIG. 11 is a diagram (1) showing a configuration example of a conventional wireless LAN.

FIG. 12 is a diagram (2) showing a configuration example of a conventional wireless LAN.

[Explanation of symbols]

 1, 1A, 1B Radio wave reflection plate 2 Master device 3 Slave device 4 Wireless LAN 5 Wired LAN 7 Personal computer 8 Printer 9 File server 10 Information terminal device 11 Microcell 12 Personal computer 13 User module 15 Control module 16 Main cable 22 Master device 23 cordless handset 24 network 25 radio wave reflection plate C ceiling surface L network line W radio wave

Claims (1)

[Claims] 1. A radio wave reflector for use in a premises information communication system comprising a master transceiver and a slave transceiver, which has a convex curved surface or a concave curved surface and is attached to a ceiling part of the premises, and the parent transceiver Alternatively, a radio wave reflector which reflects the radio wave from the slave transceiver toward the slave transceiver or the master transceiver.