JP2003262652A - Antenna test collateral apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate reception of the reflected radio waves of transmitted radio waves on a ground surface by directly receiving the wave by a receiving antenna, when the transmission polarized plane is vertical in an antenna test apparatus at an outside site at close range between the receiving antenna and a transmitting antenna. <P>SOLUTION: The antenna test subsidiary apparatus comprises a radio wave reflecting plate, disposed on the ground surface between the transmitting antenna and the receiving antenna, and a radio wave reflecting plate having a reflecting angle with the reflected radio waves on the ground surface of test radio waves radiated from the transmitting antenna being set so as not reach the receiving antenna. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna test accessory at an outdoor site where a receiving antenna and a transmitting antenna are very close to each other, and more particularly, a receiving antenna receives only a direct wave when a transmitting polarization plane is vertical. , The transmitted radio waves reflected on the ground surface are not received.

[0002]

2. Description of the Related Art In recent years, glass antennas for vehicles for receiving radio waves of various frequencies such as FM radio broadcast waves and TV broadcast waves are becoming widespread as vehicle antennas. In the development of
Various performance confirmation tests are performed to confirm the reception performance.

These performance confirmation tests include an anechoic chamber reception test in which a test antenna from a transmitting antenna arranged in an anechoic chamber that blocks various disturbance radio waves is received by a receiving antenna such as a glass antenna to confirm the receiving performance.
In addition, in an outdoor city, an actual vehicle running a vehicle equipped with a glass antenna and receiving broadcast radio waves from a broadcasting station to confirm reception performance, further,
In an outdoor test yard, there is an outdoor reception performance test in which a reception antenna receives a test radio wave transmitted from a transmission antenna provided at a close range.

Of these performance confirmation tests, in the case of a test in which a test antenna transmitted from a transmission antenna provided at a close range in an outdoor test yard is received by a reception antenna, as shown in FIG. There are a direct wave directly transmitted from 1 to the receiving antenna 2 and a reflected wave in which a radio wave that is totally reflected on the ground surface is transmitted toward the receiving antenna 2. If you want to receive only the direct wave, the reflected wave However, there is a problem in that the reception sensitivity cannot be accurately measured due to the interference.

When the distance between the transmitting antenna 1 and the receiving antenna 2 is large, there is almost no adverse effect due to mutual interference between the direct wave and the reflected wave, which adversely affects the measurement of the receiving sensitivity. is not.

For example, Japanese Laid-Open Patent Publication No. 7-55863 discloses an EMC (Electro Magneti) emitted from an electronic device.
c Compatibility, electronic device co-existence) As for the test site, the surface of the floor unit (3) with the front surface formed of a metal plane (1) and the electromagnetic wave absorber (2) attached to all or part of the back surface is used. Perfect reflection type E by laying it up and lining it up or using it on a part of the metal floor
The MC test site is constructed, and a non-reflective type EMC test site is constructed by arranging the same floor unit (3) in a fence shape on the floor below the direct wave passage. The non-reflective combined EMC test site "is disclosed, and there is a description that a floor unit whose surface is formed of a metal flat surface is provided between an electronic device that emits a radio wave and a receiving antenna to reflect the radio wave.

[0007]

However, in the case of the "perfect reflection type" described in Japanese Patent Laid-Open No. 7-55863, the direct wave received by the direct receiving antenna and the direct wave radiated from the electronic device and the floor. It receives the radio waves reflected by the reflector of the unit, receives both radio waves, and uses them so that the vector sum of them can be brought to the receiving antenna. Conversely, the reflected radio waves are generated. When it is desired to make it non-reflective so as not to prevent it, the floor unit is provided with a radio wave absorber, which inevitably increases the cost.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and is simple and simple in an antenna test facility at an outdoor site where the distance from the transmitting antenna to the receiving antenna is very short. The purpose is to make it possible to receive only the direct wave at a low cost without receiving the reflected wave of the transmitted radio wave on the ground surface.

That is, according to the present invention, in an antenna test facility at an outdoor site where the distance from the transmitting antenna to the receiving antenna is the shortest distance, a radio wave reflector is arranged on the ground surface between the transmitting antenna and the receiving antenna to transmit the signal. The antenna test accessory device is characterized in that, of the test radio waves transmitted from the antenna, the radio waves reflected by the ground surface are provided at such a reflection angle that the radio wave reflector does not reach the receiving antenna.

Alternatively, the present invention is the above-mentioned antenna test attachment device characterized in that the antenna reception sensitivity is measured when the plane of polarization of the transmitted radio wave is vertical.

Alternatively, the present invention is the above-mentioned antenna test accessory device, wherein the receiving antenna is a glass antenna for a vehicle.

Alternatively, according to the present invention, the above-mentioned antenna test is characterized in that the radio wave reflection plate has a circular shape or a rectangular shape having a diameter or a length of one side which is equal to or longer than a maximum wavelength of transmitted and received radio waves. It is an accessory device.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The antenna test accessory of the present invention has the above-mentioned configuration, whereby when the transmission polarization plane of the test radio wave transmitted from the transmission antenna 1 is vertical,
Only the direct wave directly reaches the receiving antenna 2.

Regarding the reflected wave that is totally reflected on the ground between the transmitting antenna 1 and the receiving antenna 2 when the transmission polarization plane of the test electric wave is vertical, the electric wave reflection plate 3 disposed at the reflection point where the reflected wave goes to the receiving antenna. By adjusting the installation angle with respect to the ground surface, the reflected wave is directed in a direction away from the receiving antenna 2.

By changing the installation angle of the radio wave reflection plate 3, the reflected wave totally reflected at another reflection point does not go to the receiving antenna 2 and is incident on any point on the radio wave reflection plate 3. It is necessary to set the installation angle of the radio wave reflector so that the reflected waves reflected do not reach the receiving antenna 2, and it is convenient to have a structure in which the inclination angle can be freely changed.

The radio wave reflection plate 3 may be made of a metal or metal thin film on its surface in order to reflect radio waves, and may be plate-shaped, sheet-shaped, punched metal, wire mesh, or the like.

The shape is not particularly limited, and may be circular or rectangular. The size may be such that the diameter or the length of one side is at least the wavelength of the transmission / reception radio wave, and preferably 1.5 times or more the maximum wavelength of the radio wave in the transmission / reception frequency band.

The receiving antenna 2 may be any antenna, including a vehicle glass antenna.

FIG. 1 shows an example of the embodiment of the present invention.

A dipole type receiving antenna 2 having a height of 1.5 m is erected on a turntable 4 on a pedestal provided on an outdoor test yard, 30 m from the center of the turntable 4.
A log-periodic type transmission antenna 1 having a height of 2.5 m is set up at a position distant from the transmission antenna 1 and a radio wave reflector 3 is provided at an intermediate point between the transmission antenna 1 and both antennas 1 and 2 of the turntable 4. It was installed with an inclination angle.

The turntable 4 has a length and width of 7 on each side.
A turntable 4 having a radius of 1.5 m is freely rotatable to the left and right at the center of a pedestal 5 having a height of 0.7 m and a height of 0.7 m. The receiving antenna 2 is located at a position slightly outside the center of the turntable 4. Provided.

The radio wave reflection plate 3 is formed by attaching a plate member made of stainless steel to a rectangular frame having a length and width of 7 m, and an inclination angle of 10 to 15.
Tilted in degrees.

Table 1 below shows the FM radio broadcast wave band (76-
90 MHz), TV broadcast wave LOW band (90 to 108 MH)
z), TV broadcast wave HIGH band (170 to 222 MH
z), the difference between the maximum value and the minimum value of the vertical polarization electric field strength in the frequency 76 MHz to 770 MHz of the TV broadcast wave UHF band (470 to 770 MHz) is shown before and after the installation of the radio wave reflection plate 3 of the present invention. It is a thing.

[0024]

[Table 1]

From Table 1, it can be seen that in this frequency band, the difference between the maximum and minimum values of the vertically polarized electric field strength is greatly reduced in the case where the radio wave reflection plate 3 is installed as compared with the case where it is not installed. I understand.

That is, since the radio wave reflection plate 3 is installed so that the reflected radio waves do not reach the receiving antenna 2, unnecessary ground reflected waves can be removed, variations in vertical polarization electric field strength are improved, and antenna reception sensitivity is measured. The accuracy could be improved.

Incidentally, in the reception performance test of the antenna in the outdoor open-site test yard, a means for reducing general broadcast waves other than the test radio wave, for example, modulation of the test radio wave, is carried out. It is preferable to use means for reducing the influence.

[0028]

According to the present invention, the reflected wave on the ground surface of the transmitted radio wave is not received, and only the direct wave is received. Therefore, there is no mutual buffering between the direct wave and the reflected wave, and the vertical polarization is eliminated. The accuracy of wave measurement can be improved.

[Brief description of drawings]

FIG. 1 is a side view showing a reflection state of a transmission radio wave on a radio wave reflection plate according to the present invention.

FIG. 2 is a side view showing a conventional reflected state of transmitted radio waves on the ground.

[Explanation of symbols]

1 transmitting antenna 2 receiving antenna 3 reflector 4 turntable 5 pedestals 6 earth

Claims (4)

[Claims] 1. In an antenna test facility at an outdoor site where the distance from the transmitting antenna to the receiving antenna is very short, a radio wave reflector is placed on the ground surface between the transmitting antenna and the receiving antenna, and the signal is transmitted from the transmitting antenna. Of the test radio waves,
An antenna test attachment device, which is provided at a reflection angle such that a radio wave reflected by the ground surface is prevented from reaching a receiving antenna by the radio wave reflection plate. 2. The antenna test accessory device according to claim 1, wherein the antenna reception sensitivity is measured when the polarization plane of the transmitted radio wave is vertical. 3. The antenna test accessory device according to claim 1, wherein the receiving antenna is a glass antenna for a vehicle. 4. The radio wave reflector has a circular shape or a rectangular shape whose diameter or length of one side is equal to or longer than the maximum wavelength of transmitted and received radio waves. Attached device for antenna test.