JP3137282B2 - Radio wave transmission material reflection loss measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring reflection loss of a radio wave transmitting material.

[0002]

2. Description of the Related Art A radio wave transmission type VFRC (Vinylon Fiber Re) for preventing a TV radio wave reflection obstruction by a building.
Informed concrete) curtain walls have been developed.

[0003] As a conventional radio wave reflection loss measuring device, for example, Japanese Patent Publication No. Hei 7-11547 discloses a lifter having a surface on which a flight tile as a radio wave absorbing material is adhered, a transmitting antenna for emitting radio waves from above the lifter, and a reflection antenna. The figure includes a receiving antenna for receiving waves, a control panel of a lifter, and a computer unit in which both antennas and the control panel are connected.

In this apparatus, a test sample is placed on a lifter, and a standing wave generated by moving the lifter up and down is measured to measure the reflection loss of the test sample.

When a radio wave permeable material is measured with this device, the radio wave radiated passes through the radio wave permeable material, and the radio wave absorption capability of the ferrite is finite. The transmitted radio wave exits to the surface, and the radio wave is measured. The reflection from the floor is also measured. Therefore, the reflection loss of the radio wave permeable material could not be accurately measured.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for measuring the reflection loss of a radio wave absorbing material which can accurately measure the reflection loss.

According to the radio wave transmitting material reflection loss measuring apparatus of the present invention, the radio wave absorbing material floor, the transmitting antenna and the receiving antenna installed in parallel with the radio wave absorbing material floor, and the radio wave absorbing material floor A moving device movably provided in a direction connecting the two antennas and the gantry, a gantry mounting gantry erected on the moving device, and a gantry provided on the two antenna sides of the gantry And a radio wave absorber attached to the front surface of the moving device, a measuring unit connected to the two antennas and the moving device, a distance between the test object and the two antennas connected to the measuring unit, an electric field strength, And a computer unit for requesting

[0008]

In the apparatus for measuring reflection loss of a radio wave absorbing material configured as described above, there is no radio wave reflecting material on the back surface of the test sample, and the floor is prevented from reflecting radio waves on the radio wave absorbing material floor. Therefore, the return loss can be accurately measured.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a ferrite tile floor 2 which is a radio wave absorbing material is provided on a roof 1 of a building having no tall building in the periphery.
Is laid. On one side of the floor 2, a transmitting antenna 3 and a receiving antenna 4 are erected in parallel with the floor 2.

On the other side of the floor 2, a moving device 5 is provided movably with respect to the antennas 3, 4 within a range of a distance D (for example, 2 m). On this moving device 5, a frame for mounting a test body, which is indicated by reference numeral 6 in its entirety, is provided upright.

In FIGS. 2 and 3, the gantry 6 is made of wood and simulates columns and beams.
A metal plate having the same scale as the actual steel frame, for example, an aluminum panel 9 is attached to the surface of the steel plate so that the reflection loss as the frame steel frame can be measured electrically in the same manner as the actual steel frame. Then, a thickness of, for example, 10
mm specimen such as a curtain wall (a specimen P having a 2 mm-thick acrylic plate for a formwork attached to the surface thereof, and a ferrite tile 11 attached only to the beam 7. A radio wave absorber 12 is attached to the front of the device 5.

In FIG. 5, an experimental apparatus section A is constituted by a transmitting antenna 3, a receiving antenna 4, and a moving apparatus 5 and is connected to a measuring section B. A computer section C is connected to the measuring section B. I have. The measuring unit B includes an S-parameter test set 13 to which both antennas 3 and 4 are connected.
And a network antenna 14 connected to the set 13, and a distance sensor 15 and a mobile device control unit 16 to which the mobile device 5 is connected. The computer unit C includes a central processing unit (CPU) 17 to which the network unizer 14 and the distance sensor 15 are connected.
And a display 18 and a printer 19.

Next, the mode of measurement will be described.

The measurement is performed by using a known spatial standing wave method. The transmitting and receiving antennas 3 and 4 are arranged at regular intervals and are fixed at the same height as the center of the test object P. Therefore, a weak radio wave is oscillated from the transmitting antenna 3 and hits the test object P, and the position of the standing wave caused by the reflected wave and the direct wave generated on the front surface is changed by moving the test object P, and the receiving antenna is changed. 4 was measured. At this time, the radio wave is the actual TV radio wave 90 MHz (1
ch) to 220 MHz (12 ch), which is 400 to 1100 MHz, which is about five times the frequency, and the measurement was performed at 11 frequencies equally spaced between the frequencies.

Therefore, an experiment was conducted to verify the measurement accuracy of the measuring device. That is, the mount 6 for mounting the specimen is removed,
FIGS. 6 and 7 show measured waveforms at a frequency of 750 KHz when only the moving device 5 and the radio wave absorber 12 on the front surface thereof are used (complete transmission) and when a metal plate is attached as a test body (complete reflection). Frequency 400 for mobile device 5 only
The return loss at １1100 MHz was about 35 dB or more.

Next, an experiment was conducted on the reflection characteristics of the basic plate.

With respect to a flat acrylic plate and a curtain wall having a predetermined thickness, measured values of respective reflection characteristics were compared with theoretical values.

That is, width 2100 mm, height 2400
The base plate P1 of an acrylic plate having a thickness of 13 mm and a thickness of 13 mm was vertically fixed with styrene foam which is not affected by radio waves, and the measurement was performed in a state where the base plate P1 was completely suspended in radio waves. Then, the complex permittivity of this basic plate P1 (εr = 2.65-j)
0.04) and its thickness of 13 mm, the theoretical return loss was calculated.

Similarly, width 2100 mm, height 2400 m
m, a basic plate P2 of a curtain wall having a thickness of 10 mm (ε
r = 4.5-j0.15, and an acrylic plate having a thickness of 2 mm for a formwork is provided on the surface of the curtain wall). These results are shown in FIG.

From the experimental results and the calculation results of the basic plate P1, the accuracy of the reflection loss measurement of this measuring device is known. Also, from the agreement between the experimental results of the basic plate P2 and the calculated results, the radio wave transmitting VFRC curtain is measured by the measuring device. It can be seen that the reflection measurement of the wall can be measured accurately. These are the basic plates P1, P2
On the back of the device, install a device on the roof of a tall building with no tall buildings around and use a ferrite tile floor 2 to prevent reflected waves on the floor in order to prevent reflection of radio waves at all. This is because the test is performed in the environment where the test was performed.

[0022]

According to the present invention, as described above, the return loss can be accurately measured.

In particular, if the radio wave transmitting type curtain wall has a non-uniform surface shape and partially reflects irregularly, it is necessary to use the apparatus of the present invention.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of the present invention.

FIG. 2 is a front view showing a specimen mounting stand and the specimen in FIG. 1;

FIG. 3 is a side view of FIG. 2;

FIG. 4 is a top view of FIG. 2;

FIG. 5 is an overall configuration diagram.

FIG. 6 is an electric field strength characteristic diagram showing a complete transmission experiment result of a measurement accuracy verification experiment.

FIG. 7 is an electric field intensity characteristic diagram showing a complete reflection experiment result of a measurement accuracy verification experiment.

FIG. 8 is a reflection characteristic diagram of a basic plate for explaining the effect of the present invention.

[Explanation of symbols]

 A: Experimental equipment section B: Measuring instrument section C: Computer section P: Test piece P1, P2: Basic plate 1: Rooftop 2: Ferrite tile floor 3: Transmitting antenna 4 ・ ・ ・ Receiving antenna 5 ・ ・ ・ Moving device 6 ・ ・ ・ Mounting stand 7 ・ ・ ・ Beam 8 ・ ・ ・ Column 9 ・ ・ ・ Aluminum panel 11 ・ ・ ・ Ferrite tile 12 ・ ・ ・ Radio wave Absorber 13 S-parameter test set 14 Network analyzer 15 Distance sensor 16 Moving device controller 17 Central processing unit 18 Display 19 Printer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Takashi Kosugi, Inventor Kashima Construction Co., Ltd. 2-9-1-1, Tobita-Shi, Chofu-shi, Tokyo (72) Inventor Shigeyuki Akihama 1-2-1, Moto-Akasaka, Minato-ku, Tokyo No. 7 Kashima Construction Co., Ltd. (56) References JP-A-4-155269 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 29/08-29/10 G01N 22 / 00

Claims (1)

(57) [Claims] 1. A radio wave absorbing material floor, a transmitting antenna and a receiving antenna installed in parallel with the radio wave absorbing material floor, and movably in a direction connecting the antennas and a base on the radio wave absorbing material floor. A moving device provided, a test object mounting stand erected on the moving device, a test object provided on both antenna sides of the mount and a radio wave absorbing material mounted on a front surface of the moving device. A measuring unit connected to the two antennas and the mobile device, and a computer unit connected to the measuring unit and calculating the distance and electric field strength between the test object and the two antennas. Reflection loss measuring device for radio wave permeable material.