JP4593215B2 - Interference exclusion capability test equipment - Google Patents

Description

The present invention relates to a disturbance rejection capability test apparatus for testing a disturbance rejection capability (also referred to as immunity) of an electronic device.

Conventionally, a specimen is placed in an anechoic chamber, and a radiated electromagnetic field test method in which horizontal or vertically polarized electromagnetic waves are applied to the specimen from a biconical antenna or a log-periodic antenna fixed in the same anechoic chamber. There is a TEM waveguide method using a cell and a GTEM cell. (For example, refer to Patent Document 1).
Further, as a method for increasing the test space in the TEM cell, a TEM cell formed in a substantially trapezoidal shape having a bottom surface having no tapered portion is disclosed. (For example, refer to Patent Document 2).

JP 2003-98211 A JP-A-5-264620

However, in the proposed technique described in Patent Document 1, even if the electric field strength of the test radio wave radiated from the antenna is relatively low (200 V / m), the product (test equipment) However, if it travels close to the radar equipment for guidance that is used for taking off and landing of an aircraft on a moving body such as an automobile equipped with the product, the on-board electronic equipment It has been found that problems such as malfunctions and malfunctions may occur, and in some cases, fatal failures may occur.
In order to solve this problem, the inventors tried to increase the electric field strength of the test radio wave. However, the electric field strength of 600 V / m is necessary, and this is applied to a single amplifier, as in the proposed technique. When implemented with an antenna, not only a high withstand voltage antenna is required, but also a high withstand voltage and high output power amplifying device is required, and there is a problem that the interference exclusion capability test device is physically enlarged. It was.
Also, if a TEM cell with low transmission loss of radio waves radiated from the antenna is used, the electromagnetic field level radiated from the antenna can be lowered, so that an electric field strength of 600 V / m can be obtained relatively easily on the test plane. it can. However, the TEM cell has a smaller test space than the radiated electromagnetic field test method, and in order to accommodate the EUT in the TEM cell, a small EUT storage door provided in the TEM cell is opened, There was a problem that the workability was remarkably deteriorated because the specimen had to be accommodated.

Therefore, the present application has been made to solve these problems, and its purpose is to eliminate the interference that can obtain the electric field strength within the specified range in the test plane even when a low-power power amplifier is used. It is to provide a test device.
Another object is to provide a disturbance exclusion capability test device that facilitates installation of the EUT.
Another object is to provide a low-cost interference exclusion capability test device.
Another object is to provide a disturbance rejection test device that is not affected by reflected waves.

The invention described in claim 1 made to achieve such an object,
A signal generator for generating a high-frequency signal,
Comprising a probe for radiating electromagnetic waves into the waveguide section, and the horn antenna configured to emit to the outside electromagnetic waves emitted from the probe through the horn,
An amplifying device that radiates an electromagnetic wave from the probe by amplifying a high-frequency signal from the signal generator and supplying the amplified signal to the probe;
A turntable formed of an insulating material on which the EUT can be placed ;
The provided, are summarized as interference exclusion capability testing apparatus characterized in that a said turntable before Symbol horn antenna in the horn.

The invention described in Claim 2 is the interference exclusion capability testing apparatus according to claim 1, the pre-Symbol horn antenna, is characterized by being installed in the anechoic chamber.

According to the interference exclusion capability testing apparatus of the first aspect, since the turntable for mounting the EUT is installed in the horn of the horn antenna, the probe radiates from the horn of the horn antenna. The test equipment can be irradiated with the electromagnetic wave. Therefore, even if a low-power power amplifying device is used as the amplifying device, an electric field strength within the standard range can be obtained on the test plane, and a low-cost interference elimination capability testing device that can easily install the EUT is provided. can do.

Further, according to the invention described in claim 2, since the horn antenna is installed in a room electrodeposition Namimuhibiki can provide not affected by the reflected wave interference exclusion capability testing apparatus.

Hereinafter, an example of an embodiment embodying the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory diagram of a disturbance exclusion capability test apparatus according to a first embodiment to which the present invention is applied.
1 is a horn antenna, 2 is a probe, 3 is an EUT, 4 is a turntable, 5 is a signal generator, 6 is a power amplifier, 7 is a transmission line, 8 is an anechoic chamber, and 9 is an electromagnetic wave absorber. is there. Reference numeral 10 denotes a disturbance exclusion capability test apparatus.

The radio wave absorber 9 is affixed to the entire inner surface of the radio anechoic chamber 8 and absorbs the electromagnetic wave radiated into the radio anechoic chamber and the electromagnetic wave reflected by the test equipment and converts it into thermal energy. Is for.
Inside the anechoic chamber 8, the horn antenna 1 is provided, in the interior of the horn said horn antenna 1 and the turntable 4 is provided, the EUT 3 over the turntable 4 It is placed. The turntable 4 is formed of an insulator having a high electromagnetic wave transmittance, and for example, a synthetic resin material is used.
In addition, a probe 2 for radiating electromagnetic waves is provided in the waveguide of the horn antenna 1, and the probe 2 is close to the opening surface by approximately a quarter of the wavelength from the wall surface of the waveguide of the horn antenna 1. It is attached to. The horn antenna 1 and the probe 2 are made of a conductive material.
In this embodiment, a circular horn antenna is used, but a rectangular horn antenna may be used.
In this embodiment, the signal generator 5 is an oscillator that sweeps 1 to 1.5 GHz.
The power amplifying device 6 is for amplifying the high frequency signal generated by the signal generator 5 to have a predetermined power.
The transmission line 7 is a highly shielded coaxial cable that can reduce the effect of electromagnetic waves without the high-frequency signal being attenuated.

Next, the operation will be described.
The 1 to 1.5 GHz sweep signal generated by the signal generator 5 is amplified by the power amplifying device 6 (using 200 W in this embodiment). The amplified high-frequency signal is supplied to the probe 2 and radiated from the horn antenna 1 toward the EUT 3. Then, a uniform electromagnetic field is generated on the test plane (φ30 cm in this embodiment) of the turntable 3 on which the EUT 2 is placed.
In addition, the electromagnetic wave that has passed through the EUT 3 and the reflected wave reflected by the EUT are absorbed by the radio wave absorber 9 and converted into thermal energy.

Next, the supply power of the probe 2 necessary for realizing an electric field strength of 600 V / m at 1.3 GHz on the test plane is obtained.
First, when the received electric field strength is converted from 600 (V / m) to a unit of (dBμ / m),
Received electric field strength A = 20 × Log (600 × 1E6)
Here, aEb represents a × 10 to the bth power.
Therefore,
A = 175.56 (dBμ / m)
It becomes.

Next, the electric field strength (dBμ / m) is converted into a voltage (dBμ).
Voltage Et = E + G + Le− (Lf × L) −6
Where Et = receiver input signal voltage (dBμ)
E = field strength (dBμ / m)
G = antenna gain (dBi) where 0 dBi.
Le = effective length of antenna (dB)
= 20 × Log (λ / π)
λ = wavelength (m)
Lf = Cable loss per unit length (dB / m)
L = Cable length (m) where 0 m.
6dB correction for conversion from open value to end value
λ = 3E8 / 1.3E9
= 0.23 (m)
Le = 20 × Log (0.23 / 3.14)
= -22.7 (dB)
Et = 175.56-22.7-6
= 146.86 (dBμ)
It becomes.

Next, the voltage (dBμ) is converted into electric power (dBm).
Power Pi = Et−20 × Log (√0.001 × √50 × 1E6)
Where Pi = reception level (dBm)
Et = receiver input signal voltage (dBμ)
Therefore,
Pi = 146.86-20 × 5.35
= 39.86 (dBm)
It becomes.

Here, if the loss Γ1 of the horn antenna is −1 dB, the supplied power P is
P = Pi-Γ1
= 39.86 + 1
= 41 (dBm)
= 13 (W)
It becomes.

The ratio of the cross-sectional area of the surface perpendicular to the axis of the horn at the position of the side surface of the EUT facing the probe to the cross-sectional area of the side surface of the EUT facing the probe is -12 dB (about 6%). Then, the supplied power P is
P = Pi−Area ratio (dB)
= 41 + 12
= 53 (dBm)
= 200 (W)
It becomes. When the area ratio is described in detail, an electromagnetic field is generated in the horn.
This is because all of the electromagnetic waves are not irradiated onto the EUT, so it is necessary to control the supplied power according to the size of the EUT that is actually irradiated.
On the other hand, in order to obtain an electric field strength of 600 V / m by the conventional method of radiating into free space, 28 (KW) of supplied power is required as shown below.
Supply power Pf in the case of radiating into free space is obtained by the following equation.
Pf = Pi + Γ0
Here, Γ0 = Free space propagation loss (34.7 dB)
Therefore,
Pf = 39.86 + 34.7
= 74.56 (dBm)
= 28576 (W)
It becomes.
Therefore, by applying the present invention, it is possible to obtain the required performance with a power supply of about 1/140.

In this way, because the EUT is placed inside the horn antenna, a uniform electromagnetic field can be generated on the test plane on which the EUT is placed without loss of electromagnetic waves radiated from the horn antenna. Compared to the conventional method of radiating into space, the loss is smaller than the loss in the propagation path (the free space propagation loss Γ0 of the distance between transmission and reception is 1 m, frequency 1.3 GHz is 34.7 dB). An excellent effect of reducing the power to be reduced to about 1/700 is obtained.

Next, a second embodiment of the present invention will be described with reference to FIG. In the following description, the same components as those in the signal processing apparatus of the first embodiment are given the same reference numerals, and detailed description thereof is omitted.
In FIG. 2, the interference rejection capability test apparatus 20 includes a radio wave absorber 21 and a wall body 22 instead of the radio anechoic chamber 8. The size of the radio wave absorber 21 is preferably at least approximately equal to the area connecting arbitrary points on the horn extension line of the horn antenna 1. With such a configuration, it is not necessary to provide a large anechoic chamber 8 and it is possible to efficiently test in a narrow space. When a wide space is obtained in the electromagnetic wave radiation direction, the radio wave absorber 21 and the wall body 22 may be omitted.

Next, a third embodiment of the present invention will be described with reference to FIG. In the following description, the same components as those in the signal processing apparatus of the first embodiment are given the same reference numerals, and detailed description thereof is omitted.
In FIG. 3, the disturbance exclusion capability test apparatus 30 shows an example in which the polarization plane of the electromagnetic wave radiated to the EUT 3 can be arbitrarily changed.
The circular waveguide 1a closed at one end is provided with a flange 1d, a gear 1c, and a coaxial connector 1b. The horn 1f is also provided with a flange 1e. Then, the flange 1d and the flange 1e are fitted and fixed to the fixture 24a by the flange fixture 25.
The antenna mounting bracket 24 is provided with fixtures 24a and 24b for fixing the horn antenna, and of these, the motor 23 is attached to the fixture 24a. A gear attached to an electric motor and the gear 1c are fitted to rotate the circular waveguide 1a in the axial direction.
By driving the electric motor 23, the circular waveguide 1a is rotated, the angle of the probe built in the circular waveguide is changed, and the polarization plane of the electromagnetic wave radiated from the probe is changed. In addition, since the EUT 3 (in other words, the horn 1f) is fixed to the fixture 24, it is possible to irradiate an electromagnetic wave having a polarization plane corresponding to the angle of the probe. With this configuration, the angle of the probe can be adjusted arbitrarily, and the types of polarized waves that can be tested such as horizontal polarization, vertical polarization, and rotating magnetic field can be increased.

It should be noted that the present invention is not limited to the above-described embodiment, and can be implemented by appropriately changing each part without departing from the spirit of the present invention, as exemplified below.
For example, in this embodiment, the EUT is placed in the horn. For example, a waveguide fitting with the end of the horn is connected to the opening of the horn, and the EUT is installed in this waveguide. The effect can be obtained in the same manner as described above. Moreover, although 1-1.5 GHz was used as a test frequency in a present Example, it is not limited to this, If it is VHF band-SHF band, it can be used.

It is explanatory drawing of the disturbance exclusion capability test apparatus to which the 1st Example is applied. It is explanatory drawing of the disturbance exclusion capability test apparatus to which the 2nd Example is applied. It is explanatory drawing of the disturbance exclusion capability test apparatus to which the 3rd Example is applied.

Explanation of symbols

10.20.30: Interference rejection capability test apparatus, 1 ... Horn antenna, 2 ... Probe, 3 ... EUT, 4 ... Turntable, 5 ... Signal generator, 6 ... Power amplifier, 7 ... Transmission line, 8 ... Anechoic chamber, 9.21 ... Absorber, 22 ... Wall, 23 ... Electric motor, 24 ... Antenna mounting bracket, 25 ... Flange fixture.

Claims (2)

A signal generator for generating a high-frequency signal,
A horn antenna having a probe for radiating electromagnetic waves inside the waveguide, and configured to radiate electromagnetic waves radiated from the probe to the outside via the horn;
An amplifying device that radiates an electromagnetic wave from the probe by amplifying a high-frequency signal from the signal generator and supplying the amplified signal to the probe;
A turntable formed of an insulating material on which the EUT can be placed ;
The provided, interference exclusion capability testing apparatus characterized in that a said turntable before Symbol horn antenna in the horn. The pre-Symbol horn antenna, interference exclusion capability testing apparatus according to claim 1, characterized by being installed in the anechoic chamber.

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