JPS60170769A - Measuring device for nearby electric field - Google Patents

Abstract

PURPOSE:To correct an error in received nearby electric field value due to the position error of a probe in a short time, and improve the accuracy of directivity by arranging plural measuring probes at distance less than in-use wavelength at right angles to a scanning surface. CONSTITUTION:A probe 22 is driven in an x-axis direction by a probe driving device 29 and pieces of position information on probes 22-a and 22-b detected by a probe position detector 30 are sent to a computer 27. When the position of the probe 22-a or 22-b coincides with a measurement position, the computer 27 uses a switch 24 for microwaves to receive the output of the waveguide probe 22-a or 22-b through a receiver 26 and then stores it in a device 28. Then, the function of a phase error value and an amplitude error value to a probe position error displacement value is calculated to correct a measurement result on a two- dimensional plane on which data are collected. Thus, all collected data are corrected to calculate a nearby electric field value on a desired scanning surface equivalently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a near electric field measuring device that measures an electric field in the vicinity of an antenna to be measured, and particularly relates to a probe arrangement method C2.

[Technical background of the invention and its problems]

A conventional plane scanning near-field electric field measuring device consists of an antenna under test 1, a transmitter 2 feeding the antenna under test 1, and a probe 3 measuring the electric field of the antenna under test, as shown in FIG.
It consists of a device 4 for driving this probe, a receiver 5, and a device 6 for accumulating and processing measurement data.

Near-field electric field measurement (in step 2, two probes with different characteristics are used to first measure the amplitude and phase of the near-field electric field at each measurement point C2 on a two-dimensional plane using only one probe,
Next (=This measurement is performed with a probe that has two different characteristics.

General (Secondly, the antenna to be measured is scanned on a two-dimensional plane with a probe 3 that measures only the X polarized wave, and measures the amplitude and phase of each measurement point. Rotate and perform the same measurements as above for the X polarization.

Based on the measured values for the x and

In this measurement method, at defined measurement sample points.

Accurately (need to measure the amplitude and phase of two electric fields.

In an actual measurement system, the glove position error (x-y plane, scanning plane and i
f'1.9 direction (z-axis direction)) is generated.

For this reason, the probe received signal (contains two errors), and the far-field radiation directivity of the antenna to be measured cannot be accurately determined, resulting in errors.

Of the probe position errors, the probe error in the scanning plane (-direct firing direction) is the factor that causes the most directivity error.

It is possible to increase the manufacturing accuracy of the scanning frame, but for high-precision measurement (2 is about λ/250 (λ two wavelengths) or less), there is a limit to the manufacturing accuracy at high frequencies.

Conventionally, a method for correcting this probe position error is to solve simultaneous equations in which the number of measurement samples is equal to C', and to obtain a desired neighboring electric field value. If the number of samples is 10,000 or more (20,000 to 40,000 for a large-aperture antenna under test), the calculation time to calculate the nearby electric field value will take several hours or more.This method is suitable for antenna measurement. It takes too much time and is inefficient.

[Purpose of the invention]

The present invention has been made in view of the above points.

A plurality of probes are used to measure the magnetic field in the vicinity of the antenna to be measured, and the probes are placed in a direction perpendicular to the scanning plane (2), separated by a distance within the wavelength used. Provides a near-field magnetic field 611 fixing device that can correct errors in near-receive electric field values due to position errors in a short time, eliminates errors that occur in the far-field directivity of the antenna to be measured, and improves the accuracy of the obtained directivity. The purpose is to

[Summary of the invention]

The present invention is a system in which a plurality of probes are used to measure the electric field near the antenna under test, and the distance between the apertures of the two globes is separated by a distance within the wavelength used. The present invention provides a near electric field measurement device that measures the near electric field value of an antenna.

〔Effect of the invention〕

The error in the near electric field value of the globe received signal caused by the probe position error in the direction 11'1 intersecting with i++yi can be corrected in a short way, and the probe position error (
On the far-field directivity of the antenna under test due to
) J direction 1% song 7 reward can be eliminated.

Therefore, this method is effective when high precision measurement is required.

It was long. By using this method, the manufacturing accuracy of the globe scanning frame can be lowered, so the measuring device can be made cheaper.

[Embodiments of the invention]

A real-life example of the present invention is shown in FIG.

The present invention includes a transmitter side, a fixed antenna 21 to be received, a plurality of globes 22, a scanning frame device for driving the globes on a two-dimensional plane, a switching device 24 for switching the F signal from the globes, and a receiving device. 8i! The control device includes a control device including a receiver and a computer, a device 28 for storing received signals, a device 4 for driving the probe, and a device 3o for detecting the position of the glove.

This will be explained below using specific examples.

The antenna to be measured 31 and two open antennas shown in FIG.
Consider a measurement system consisting of ended guided waves $22-a and 22-b. In FIG. 3, 35 is the scanning locus in the z-axis direction (a desired scanning surface without any nibrobe position error) due to the probe position error that actually occurs in the morning.

Then, the distance d between the waveguide probes 22-a and 22-b is set to be equal to the wavelength (two) at the operating frequency.

Furthermore, the distance xhcls between the two gloves in the X-axis direction is appropriately selected and arranged.

Here, the electric field near the antenna under test is measured by the probe 22-
If measurements are made at the same measurement point on the X axis in a and 22-b, changes in the received signal due to positional errors in the two axis directions of the probe can be compared using nearby electric field values.

With this probe system, the probe n is moved in the X-axis direction (two times) at the grave of the glove drive device shown in FIG. When the position of the probe 22-a and the measurement position match, the device uses the microwave switch 24 to connect the output signal of the waveguide globe 22-a to the receiver.

The output signal of 22-b is terminated without reflection, and the output signal of probe 22-a is
Only the signal of 1 is loaded into the capture device 28.

Next, when the position of the glove 22-b and the measurement position match, the connection is made in the opposite direction to that described above, and data is collected.

When collecting data on such nearby electric field values.

An area including a desired scan plane can be scanned and measured in one go.

In order to accurately measure the far-field directivity of the antenna to be measured (second), it is necessary to scan the desired scanning plane. A probe position error in the z111i1 direction has occurred with a trajectory given by the term generated due to the error.

Therefore, the near magnetic field values obtained from the probes 22-a and 22-b include the received signal error due to the globe position error 32 described above.

Therefore, if the same near electric field value obtained on the desired scanning plane can be obtained by correcting the near electric field value (2 pairs) obtained from the above-mentioned globe 22-a, I), the influence of the probe position error can be eliminated. It can be removed.

Therefore, in FIG. 4, the probe 40 at the point x=Xo
41 in two axial directions (2d (wavelength used) and ds in the X-axis direction.

Consider the 5-water bucket old method at X=-X on the X-axis. Thisζ
Then, the maximum error in the two directions of the scanning frame is d' x = x, and the probe 40 is deviated from the desired scanning plane by d.

Here, the reception signals of the measurement points received by the probes 40 and 41 are 11], (A, 8.φl), 11](~, φ,)
shall be. (A.

Amplitude, φ phase) This reception (i signal (neighboring electric field value corrected for two is lt)) (A, φ).

Therefore, in Fig. 5, the frequency 12()t(z)
-band standard horn neighborhood 10λ (the above 2 in 2
The relationship between the phase error amount Δφ and the amplitude error amount ΔN due to the position error ΔZ in the torsion direction is shown.

From this figure, when the probe position error △Z in the direction perpendicular to the scanning plane is small compared to the wavelength, both the phase errors ΔA and Δφ are punished by linear functions with respect to the probe position error displacement ΔZ. do.

Therefore, the following method is used to correct the measurement results on the two-dimensional plane that have been collected using the method described above. Measured amplitude value AI1 phase value φl of the globe 40.

The measured four-axis width value At + phase value φ2 of the probe 41 is called out, and the distance between the niger lobe 40 and the desired scanning plane is calculated.

The signal 11] having the amplitude value A1 and the phase value φ is approximately the received signal (2) at the measurement point on the desired scanning plane at X=X.

At this time, the relationship between the maximum displacement d' of the scanning frame and the error d''X can be determined in advance by using a laser optical measuring device commercially available from HP.

In addition, the above correction calculation requires significantly less calculation time than the conventional method of solving simultaneous equations (2).

If this correction is performed for all collected data (2), it is possible to set the near electric field value on the desired scanning plane to the equality constraint.

Therefore, this method can obtain the same accuracy as the conventional method, which solves simultaneous equations and calculates the nearby electric field value.

The equivalent value on the desired scanning plane determined using this correction method is the directivity error caused by the blowoff position error in the Z-axis direction, if the far-field radiation directivity of the Ambuna to be measured is calculated using the nearby electric field value. 75E can be eliminated.

Furthermore, in this correction method, if three or more [lobes] are used, polynomial approximation can be performed, so that the nearby electric field value can be determined more accurately.

It seems that the above two Cs are connected (-1 All of the conventional methods?ll!I
Compared to the method of solving simultaneous equations equal to the number of fixed points and determining the desired field, this method is effective because it can significantly shorten the antenna measurement time by two hours.

Furthermore, by using this correction method, there is no need to increase the fidelity of the measuring device, so the manufacturing cost of the scanning frame etc. can be reduced (-
You can.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional near-field electric field measuring device, FIG. 2 is a diagram showing an embodiment of the present invention, and FIGS. 3 and 4 are
FIG. 5 is a diagram showing the relationship between the probe position error and the received signal. 1...Antenna to be measured 2...Transmitter 3...Globe 4...Device for scanning the globe 5...Receiver 6...Data storage and processing device...Transmitter 2]
・・Antenna to be measured ・・Glove ・・Device for scanning a two-dimensional plane like a probe ・
...Microwave phase switch 6...Mixer field...
・Receiver 1n machine n...CPU 28...Data storage device 29...Glove drive device blade...Position detection device Patent attorney Kensuke Norichika (one idiot) Figure 1 Figure 3 4 Figure 5 Diagram, Dk, 0. I O, l”r rnntAX (Glove a” ■ slope L)

Claims (1)

[Scope of Claims] An antenna to be measured, a transmitter for feeding power to the antenna to be measured, a globe for measuring an electric field near the antenna to be measured, a device for driving the globe, and a device for detecting the position of the globe. A plane scanning near electric field measuring device comprising a device for acquiring the probe reception signal, a device for acquiring the probe reception signal, and a device for storing the reception signal information, comprising a plurality of the gloves. A near-field electric field measuring device characterized in that the probe is arranged in a direction perpendicular to the scanning plane, and the distance between the aperture surfaces of the globe is divided into two parts within the wavelength used.