JPH0711547B2 - Method of judging reflection loss of radio wave to outer wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention records and measures the reflected wave level of an electric wave obliquely incident on an outer wall material such as an electric wave absorption panel used as an outer wall to measure a reflection loss value. The present invention relates to a method for determining a reflection loss of an electric wave with respect to an outer wall, which is obtained to determine the design performance of the outer wall material.

[Prior Art] Conventionally, TV radio waves (frequency 80MHz ~ 800MHz = wavelength 375cm ~
As a method of measuring the reflection loss of an outer wall such as 37 cm), use the device shown in Fig. 3 to measure the reflected wave level for the outer wall material such as the test piece and the test piece made of a metal plate that easily reflects radio waves. However, there is a method of calculating each reflection coefficient from this measured value and calculating a reflection loss value. The device used in such a method is such that the test body 12 or the test specimen is fixed to the upper part of the lifter 11 that moves up and down, and a radio wave is transmitted from the transmission antenna 13 toward the test body 12 and the like, and the test antenna 12 and the like are received by the reception antenna 14. It is possible to receive reflected waves from. Then, the signal received by the receiving antenna 14 is input as data to the computer 16 via the radio wave measuring device 15, and the reflected wave levels of the test body 12 and the sample are calculated and recorded by the computer 16.

Next, the control board 17 is operated by the computer 16 to move the lifter 11 up and down, and the distance between the test body 12 and the receiving antenna 14 is changed to measure the reflected wave level. Then, the computer 16 calculates each reflection coefficient of the test body 12 and the test piece to obtain a reflection loss value, and it is determined from this reflection loss value whether or not the reflection loss of the outer wall material matches the design performance.

[Problems to be Solved by the Invention] However, in the device used in the above method, it is necessary to measure the reflected wave level by injecting radio waves perpendicularly to the outer wall. Therefore, in order to obtain the reflected wave level when the radio wave obliquely enters the outer wall, it is necessary to tilt the test body and move the receiving antenna largely so as to receive the reflected wave.

Therefore, since the fixing means for the receiving antenna becomes complicated and the device itself becomes large, there is a problem that a large-scale work is required for the measurement and the measurement efficiency becomes poor. Furthermore, in order to measure the reflected wave level of radio waves with high accuracy, it is necessary to reduce the influence of reflected waves from the side walls, etc., and at the same time, install antireflection plates on the side walls and ground of the radio wave shielded room where the equipment is installed. There is a need to.

The present invention was made to solve these problems, and highly accurately measures the reflection coefficient and the like when a radio wave obliquely enters the outer wall, and obtains useful judgment data. It is an object to provide a reflection loss determination method.

[Means for Solving the Problems] A method of determining a reflection loss of a radio wave to an outer wall of the present invention is a plate-like table provided on the upper part of a lifter that can be fixed at an arbitrary angle with a support shaft as a fulcrum. Place the test piece consisting of the outer wall material molded on the table on the mounting table and tilt it at an arbitrary angle, and tilt it with the same horizontal length as the test piece and the vertical length to the vertical length of the test piece. The lateral edge of the reflector formed by the length of the cotangent of the corners is fixed at a right angle to the lateral edge of the test piece on the supporting shaft side, and the transmitting antenna and the receiving antenna are vertically above the lifter. , The radio wave is transmitted from the transmitting antenna to the test body and the reflector, and the radio waves reflected once on both sides of the test body and the reflector are received by the receiving antenna and the level of the reflected wave to the test body is received signal. The test specimen is made of a metal plate, etc. Similarly, the reflected wave level for the test piece is also measured, the reflection coefficient of the test piece and the test piece is calculated from each reflected wave level, and the reflection loss value is calculated by using the frequency and incident angle corresponding to each TV station. It is characterized by obtaining the judgment data of the reflection loss for the general examination by using the radio wave.

[Operation] In the above method of determining the reflection loss of the radio wave to the outer wall, the radio wave of an arbitrary frequency is transmitted from the transmitting antenna to the surface of the test body or the reflector. Here, the radio wave incident on the surface of the test body or the like is reflected by the surface of the test body or the like and is incident on the surface of the reflector except for the radio wave absorbed by the test body or the like. Then, after being reflected by the surface of the reflector, these radio waves are received by the receiving antenna. Further, the electric wave incident on the surface of the reflection plate from the transmitting antenna is reflected on the surface of the reflection plate and then reflected on the surface of the test body except for the electric wave absorbed by the test body. Then, these radio waves are received by the receiving antenna.

The reflected wave level of the radio wave can be obtained from the reflection loss value calculated by using a computer or the like by the ratio of the current value of the radio wave signal received by the receiving antenna and the current value of the current flowing through the transmitting antenna.

If the reflected wave level (dB) Rm of the test piece, the reflected wave level (dB) Rs of the test piece, the reflection coefficient Γm of the test piece, the reflection coefficient Γs of the test piece, and the reflection loss value of the test piece are R, then The relational expression of is established.

Γm = (10 ^{Rm / 20} −1) / (10 ^{Rm / 20} +1) Γs = (10 ^{Rs / 20} −1) / (10 ^{Rs / 20} +1) R = 20 log (Γm / Γs) [Example] This invention An embodiment of a method for determining the reflection loss of radio waves with respect to the outer wall will be described with reference to FIG.

In the apparatus used in this measuring method, the computer 1 controls the control panel 2 so that the lifter 3 moves up and down. A transmitting antenna 4 and a receiving antenna 5 are fixedly arranged above the lifter-3.

Here, the transmitting antenna 4 is adapted to emit a radio wave of an arbitrary frequency, and the radio wave signal received by the receiving antenna 5 is input to the computer 1 through a network analyzer 6 used as a radio wave measuring device. Has become.

A lifter base 3a is provided on the upper end of the lifter 3, and a mounting base 7 is attached to the upper surface of the lifter base 3a. A test body 8 made of a plate-shaped outer wall material and a test body made of a metal plate having the same shape as the test body 8 can be placed and fixed on the upper surface of the mounting table 7. or,
A pin 3b is axially fixed to one side of the mounting table 7 so that the mounting table 7 can be tilted at an arbitrary angle and fixed.

Then, the reflecting plate 9 is attached so that the lateral edge of the test body 8 or the like on the side where the mounting table 7 is pivoted is aligned with the lateral edge of a reflecting plate 9 to be described later so as to form a right angle with the test body 8 or the like. Stand and fix.

The reflector 9 has the same horizontal length as the test body 8 attached to the mounting table 7, and the vertical length is the vertical length (L) of the test body 8.
Then, the length L'is obtained by multiplying the co-tangent of the inclination angle (φ) of the mounting table 7 and the test body 8.

That is, the relational expression of L ′ = L × cotφ holds.

Next, a specific method for measuring the return loss of radio waves using the above device will be described.

First, the test body 8 is mounted on the mounting table 7, the mounting table 7 is tilted at an arbitrary angle and fixed, and the reflecting plate 9 is attached to the mounting table 7. Then, the transmitting antenna 4 transmits a radio wave of an arbitrary frequency to the surfaces of the test body 8 and the reflector 9. The radio waves incident on the surface of the test body 8 are reflected by the surface of the test body 8 except the radio waves absorbed by the test body 8 and reflected by the reflector 9
Incident on the surface of. Then, after being reflected on the surface of the reflector 9, these radio waves are received by the receiving antenna 5.
Further, the radio wave incident on the surface of the reflector 9 from the transmitting antenna 4 is reflected on the surface of the reflector 9 and then reflected on the surface of the test body 8 except for the radio wave absorbed by the test body 8. Then, these radio waves are received by the receiving antenna 5.

Next, the current value of the radio wave signal received by the receiving antenna 5 and the current value of the current flowing in the transmitting antenna 4 are converted into an appropriate electric signal through a network analyzer, and data is input to the computer 1.

Then, the computer 1 is adapted to calculate the reflected wave level from the ratio of these data values. The level of the reflected wave of the test piece is measured in the same manner as the measurement for the test piece 8. In this case, the test body 8 is replaced with the test piece, and the apparatus is used in the same procedure.

In the computer 1, each reflection coefficient is obtained after calculating the reflected wave level of the test body 8 and the test piece. Then, a reflection loss value is calculated from these reflection coefficients and recorded as data.

In this calculation, the reflected wave level (dB) Rm of the test piece, the reflected wave level (dB) Rs of the test piece 8, the reflection coefficient Γm of the test piece,
Assuming that the reflection coefficient Γs of the test body 8 and the reflection loss value of the test body 8 are R, the following relational expression holds.

Γm = (10 ^{Rm / 20} −1) / (10 ^{Rm / 20} +1) Γs = (10 ^{Rs / 20} −1) / (10 ^{Rs / 20} +1) R = 20 log (Γm / Γs) 1, the control panel is operated to move the lifter 3 up and down to change the distance between the test body 8 and the receiving antenna 5. Then, the reflection loss is calculated in the same manner, a series of work is controlled by the computer 1 and measured to continuously obtain data.

Therefore, if the measurement level (dB) of each reflected wave is plotted on the vertical axis and the distance S (m) between the test object 8 and the like and the receiving antenna 5 is plotted on the horizontal axis, the relationship between them is shown in the graph shown in FIG. can do. Therefore, the reflection coefficient can be visually read to obtain the reflection loss value. Then, these operations are performed for each radio wave of the frequency and incident angle corresponding to each TV station, etc., and after graphing the measurement level, the reflection loss of the test body for the entire frequency and incident angle is examined as a whole, and the outer wall It is judged whether the reflection loss of the material matches the design performance.

[Effects of the Invention] In the method for determining the reflection loss of the radio wave to the outer wall of the present invention,
With the transmitting and receiving antennas fixed, the reflection level of the radio waves obliquely incident on the surface of the specimen can be measured.
It is possible to calculate the reflection loss value of the radio wave incident on the outer wall of the building with high accuracy. Therefore, the reflection loss of the radio waves transmitted from each TV station to the outer wall material can be generally judged according to the location condition before the building is constructed, and it can be matched with the performance in architectural design including the location condition. The outer wall material used for the building can be set.

Further, by using this reflection loss determination method, it is possible to set a radio wave absorption panel suitable for radio waves of different frequencies, radio wave transmission directions, building location conditions, and the like.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an apparatus used in the method for determining the reflection loss of radio waves to the outer wall of the present invention, FIG. 2 is a graph showing the reflection level using the apparatus, and FIG. 3 is a graph showing the conventional reflection loss. 1 is a schematic diagram showing an apparatus for measuring. 1; computer, 3; lifter 4; transmitting antenna, 5; receiving antenna 7; mounting table, 8; test piece 9; reflector

Claims (1)

[Claims] 1. A mounting table, which can be fixed at an arbitrary angle with a support shaft as a fulcrum, is provided on the upper part of a lifting lifter, and a test body made of a plate-shaped outer wall material is mounted on the mounting table. The horizontal edge of the reflector, which has the same horizontal length as the test piece and the vertical length is the vertical length of the test piece multiplied by the cotangent of the inclination angle. The side is fixed at a right angle according to the lateral end side of the support shaft side of the test body, the transmission antenna and the reception antenna are arranged vertically above the lifter, and radio waves are transmitted from the transmission antenna to the test body and the reflector. , The radio wave reflected once on both sides of the test piece and the reflector is received by the receiving antenna and the level of the reflected wave to the test piece is measured from the received signal, and the test piece is changed to a test piece made of a metal plate, etc. Similarly, the reflected wave level for the specimen is also measured, and from each reflected wave level Calculate the reflection coefficient of the test piece and the test piece, and calculate the reflection loss value with the radio wave of the frequency and incident angle corresponding to each TV station etc. to obtain the reflection loss judgment data for the overall study. A method for judging reflection loss of radio waves to an outer wall, which is characterized by the following.