JP2006038503A - Instrument for measuring electric wave absorption characteristic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To confirm shifts in positioning correspondence with respect to a measured object of a transmission antenna and a reception antenna to facilitate positioning for each of the antennas, in electric wave absorption characteristic measurement. <P>SOLUTION: In this electric wave absorption characteristic measuring instrument, the antenna for emitting an electric wave out of the transmission antenna 1 and the reception antenna 2 is selectively switched by switches 21, 22, and an intensity distribution of the received electric wave on an installed face 4 of the measured object when the electric wave is emitted from the each antenna is measured based on a received signal by each of a plurality of flat antenna elements 3 arrayed on the installed face 4. Both measured results of the intensity distributions measured as to respective cases where the electric waves are emitted respectively form the two antennas are compared to correct the positional shifts in the respective antennas. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a radio wave absorption characteristic measuring apparatus used for obtaining a measurement signal by irradiating a measurement object having radio wave absorption characteristics with a radio wave from a transmission antenna and making the reflected radio wave incident on a reception antenna.

As wireless communication devices such as mobile phones, wireless LANs, and ETCs (automatic toll collection systems) become widespread and the use of radio waves spreads, the demand for radio wave absorbers has increased. Such radio wave absorbers are used not only in situations where radio waves are incident almost vertically but also in situations where the radio wave has a large incident angle. Angular dependency evaluation is required.
FIG. 4 is a diagram schematically showing a radio wave absorption characteristic measuring method for the incidence angle dependency evaluation.
As shown in FIG. 4, the measurement object 11 (radio wave absorber) placed at a predetermined position is irradiated with radio waves from the transmission antenna 1 and the reflected radio waves are incident on the reception antenna 2 to obtain a measurement signal. . At that time, each of the transmitting antenna 1 and the receiving antenna 2 is symmetric with respect to the direction of the perpendicular 14 on the surface of the measuring portion 11a with respect to the measuring portion 11a of the device under test 11 (angles a and b in the figure). Etc.), the incident angle of the radio wave to the device under test 11 is changed, and a measurement signal (received signal by the receiving antenna 2) is obtained for each change. Thereby, the incident angle dependence of the radio wave absorption characteristic of the DUT 11 can be evaluated from the relationship between the incident angle of the radio wave to the DUT 11 and the attenuation level of the measurement signal. For example, for a reference surface (such as the installation surface of an object to be measured) that has a known radio wave absorption characteristic such as a metal plate that totally reflects radio waves, the relationship between the incident angle of the radio wave and the attenuation level of the measurement signal is measured in advance as reference data. The incident angle dependence of the radio wave absorption characteristics of the device under test 11 can be evaluated by comparing this with the measurement signal for the device under test 11.
In general, the output of a high-frequency reference signal to the transmission antenna 1 and the input of the measurement signal received by the reception antenna 2 and the measurement of the signal strength and phase of the measurement signal are performed by a vector network analyzer.
Further, as a specific example of the measuring apparatus that realizes the measurement shown in FIG. 4, for example, FIG. 26 of Patent Document 1 has a configuration in which a transmitting antenna and a receiving antenna are movably attached to an arched antenna support. It is shown.
Similarly, FIG. 27 of Patent Document 1 has a configuration in which a plurality of pairs of transmitting antennas and receiving antennas arranged at symmetrical positions are provided, and the input path of the measurement signal is switched by a signal line switching device. It is shown.
No. 2002-111277

However, in the measurement of the radio wave absorption characteristics, the receiving antenna 2 receives the radio wave irradiation area (hereinafter referred to as a transmitting antenna corresponding area C1) to the surface of the object 11 to be measured and the area of the surface of the object 11 to be measured. If there is a deviation in the area where the possible radio wave is reflected, that is, the radio wave irradiation area on the surface of the DUT 11 when the radio wave is irradiated from the receiving antenna 2 (hereinafter referred to as a receiving antenna corresponding area C2) As a result, the intensity of the radio wave received by the receiving antenna decreases, and the radio wave absorption characteristics of the object to be measured are not accurately reflected in the measurement signal, resulting in a problem that the measurement accuracy deteriorates.
FIG. 3 schematically shows the correspondence relationship of the radio wave irradiation area with respect to the measured object of the transmitting antenna and the receiving antenna (shift between the transmitting antenna corresponding area C1 and the receiving antenna corresponding area C2).
In general, when the transmitting antenna 1 or the receiving antenna 2 is a horn antenna, when the transmitting antenna 1 or the receiving antenna 2 is arranged so that the front direction is opposed to the device under test 11 in the vertical direction, the radio wave irradiation area on the surface of the device under test 11 (the transmission The antenna corresponding area C1 and the receiving antenna corresponding area C1) form a slightly flat elliptical shape (not shown). When each of the transmitting antenna 1 and the receiving antenna 2 is arranged with its front direction facing in an oblique direction that is symmetrical on both sides with respect to the normal direction of the device under test 11, as shown in FIG. The area C1 and the reception antenna corresponding area C2 form an elongated ellipse. Then, as shown in FIG. 3, when the areas C1 and C2 are displaced, a part of the reflected radio waves received from the radio wave transmitted from the transmission antenna C1 (the radio wave reaching the transmission antenna corresponding area C1) is received. Without reaching the antenna 2, the radio wave absorptivity of the DUT 11 is measured as a value higher than the actual value.
In order to avoid such a problem, it is conceivable to improve the positioning accuracy of the antennas 1 and 2 with respect to the object to be measured 11 and the accuracy of the radio wave emission (incident) direction of the antennas 1 and 2. However, in that case, it is necessary to increase the rigidity of the support mechanism of each antenna 1 and 2 and also requires an extremely high-precision positioning mechanism, which increases the size, weight, complexity, and cost of the device. There was a point. Furthermore, since the transmitting antenna corresponding area C1 and the receiving area corresponding area C2 cannot be visually confirmed, it is difficult to recognize the occurrence of a shift between them, and it is difficult to ensure the reliability of measurement data.
Accordingly, the present invention has been made in view of the above circumstances, and the object of the present invention is to have a simple configuration and a correspondence relationship between positioning of a transmitting antenna and a receiving antenna with respect to an object to be measured in radio wave absorption characteristic measurement, that is, An object of the present invention is to provide a radio wave absorption characteristic measuring apparatus that can confirm a deviation between the transmitting antenna corresponding area C1 and the receiving antenna corresponding area C2 and facilitate positioning of each antenna.

In order to achieve the above object, the present invention adjusts the position of each of the two antennas, irradiates the object to be measured with the radio wave from one antenna, and enters the reflected radio wave into the other antenna to obtain a measurement signal. The present invention is applied to an absorption characteristic measuring apparatus, and can switch between which of the two antennas emits radio waves, and a plane including the measurement surface when the object to be measured is arranged at a measurement position or It has a function of measuring the intensity distribution of received radio waves in a nearby plane (hereinafter referred to as a specific plane).
Thus, for each of the cases where radio waves are irradiated from each of the two antennas (any one), it is possible to measure the intensity distribution of the received radio waves on the specific plane without installing the object to be measured. The intensity distribution represents the radio wave irradiation area (the transmitting antenna corresponding area C1 and the receiving antenna corresponding area C2) corresponding to each of the two antennas (the relatively high intensity portions are the areas C1, C2). Accordingly, it is possible to confirm the correspondence relationship between the positioning of the transmitting antenna and the receiving antenna with respect to the object to be measured, that is, the shift between the transmitting antenna corresponding area C1 and the receiving antenna corresponding area C2.
More specifically, a plurality of planar antenna elements arranged in a plane are arranged on the specific plane, and reception surfaces of the plurality of planar antenna elements are based on reception signals from the planar antenna elements. It is conceivable to measure the intensity distribution of the received radio wave at.
This can be realized with a simpler configuration than when the specific plane is physically scanned to measure the radio wave intensity distribution.
Further, the position and orientation of one or both of the two antennas can be adjusted, and both measurement results of the intensity distribution measured for each case where radio waves are emitted from each of the two antennas can be compared, for example, , If each intensity distribution is output as a visible and comparable image on a recording medium such as display means or paper, it is possible to grasp the position of each antenna at a glance and check the position while checking the position. The position and orientation of each antenna can be easily adjusted to correct.
On the other hand, the position and orientation of one or both of the two antennas can be adjusted, and both measurement results of the intensity distribution measured for each case where radio waves are emitted from each of the two antennas are compared. If a function for automatically adjusting the position and orientation of one or both of the two antennas through an actuator or the like based on the comparison result is provided, it is more preferable because it saves the user's trouble.

When a plurality of planar antenna elements are used, each received signal is sequentially switched and selected, and based on each of the sequentially selected signal strengths, the received radio wave on the receiving surface of the plurality of planar antenna elements is selected. It is conceivable to measure the intensity distribution.
As a result, the means for measuring the received radio wave of the planar antenna element can cope with one input (it is not necessary to be able to input a plurality of inputs in parallel (multiple inputs)), and the configuration becomes simple.
Further, in this case, a vector network analyzer used in measuring the object to be measured, that is, a reference signal for outputting a radio wave to one of the two antennas and a measurement signal received by the other antenna The vector network analyzer (usually one input) that inputs the signal and inputs the selected signals in sequence, so that the vector network analyzer can be used for both the radio wave distribution measurement and the measurement of the object to be measured. It becomes possible.

According to the present invention, it is switched between which of the two antennas in the radio wave absorption characteristic measuring apparatus the radio wave is emitted, and the plane including the measurement surface when the object to be measured is arranged at the measurement position or a plane in the vicinity thereof ( Since it is possible to measure the intensity distribution of received radio waves in the specific plane), it is possible to confirm the deviation between the radio wave irradiation areas corresponding to the two antennas, that is, the transmission antenna corresponding area C1 and the receiving antenna corresponding area C2. Is possible. As a result, each antenna can be easily positioned. In addition, it is not necessary to increase the rigidity of the support mechanism of each antenna or to provide an extremely high-precision positioning mechanism to the extent that no problematic positional deviation occurs, and the apparatus can be configured simply.
For example, in a state where a plurality of planar antenna elements arranged in a plane are arranged on the specific plane, if the intensity distribution of the received radio wave on the receiving surface is measured based on the received signal by each of the planar antenna elements, This can be achieved with a simpler configuration than measuring the intensity distribution of radio waves by physically scanning a specific plane.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
Here, FIG. 1 is a diagram showing a schematic configuration of a radio wave absorption characteristic measuring apparatus X according to an embodiment of the present invention, and FIG. 2 shows a radio wave intensity distribution on an installation surface of an object measured by the radio wave absorption characteristic measuring apparatus X. Fig. 3 is a diagram showing a screen example of the result of image output. Fig. 3 is a diagram schematically showing the correspondence of the radio wave irradiation area to the measured object of the transmitting antenna and the receiving antenna. Fig. 4 is a schematic diagram of the method for measuring the radio wave absorption characteristics. FIG.

Hereinafter, a radio wave absorption characteristic measuring apparatus X (hereinafter referred to as a measuring apparatus X) according to an embodiment of the present invention will be described with reference to the configuration diagram of FIG.
The measuring device X supports each of the two antennas of the transmitting antenna 1 and the receiving antenna 2 with flexible support portions 10a and 10b (an example of antenna position adjusting means) whose angles can be adjusted, and the flexible support portions 10a, 10b, Each position of 10b is supported by a positioning mechanism that positions the object to be measured symmetrically on both sides with respect to a perpendicular line at the center of the mounting base 4 of the object to be measured by a link mechanism (not shown). By adjusting the positioning mechanism and the flexible support portions 10a and 10b, the positions and directions of the two antennas 1 and 2 are adjusted, and the installation antenna 4 or the object to be measured placed thereon is adjusted from the transmission antenna 1. The incident angle of the radiated radio wave can be changed, and the position of the receiving antenna 2 can be adjusted to a position and direction in which the reflected radio wave can be received in a direction symmetrical to the incident.
The measuring apparatus X outputs a high-frequency reference signal to the transmitting antenna 1 to emit a radio wave, and irradiates the object to be measured placed on the installation table 4 with the radio wave. A vector network analyzer 7 that inputs a reflected wave as a measurement signal via the receiving antenna 2 and measures the signal intensity, phase, etc. when the radio wave (the reference signal) is displaced in its traveling path, and the measurement result And a computer 8 such as a personal computer for evaluating (measuring) the radio wave absorption characteristics of the object to be measured. The computer 8 evaluates (measures) the radio wave absorption characteristics of the object to be measured by executing a predetermined arithmetic program installed in advance.

In the present embodiment, an extremely thin plate-shaped object to be measured is assumed as the object to be measured. Therefore, the surface of the installation table 4 (installation surface of the object to be measured) is a plane very close to a plane including the measurement surface of the object to be measured arranged on the installation table 4 (measurement position) ( An example of a specific plane).
The measuring device X includes a plurality of planar antenna elements 3 that are two-dimensionally arranged on the surface (an example of a specific plane) of the installation table 4 of the object to be measured, and are composed of patch antennas, and the reference of the vector network analyzer 7. Output-side switches 21 and 22 (an example of radio wave output switching means) connected to the signal output end and capable of switching which of the two antennas (transmitting antenna 1 and receiving antenna 2) emit radio waves. It has.
In addition, the measurement apparatus X inputs the received signals of each of the plurality of planar antenna elements 3 via a line 5 such as a microstrip line and selects one of them to the input end side of the vector network analyzer 7. The vector network analyzer 7 measures any one of the multiplexer 6 to be output, the output signal of the multiplexer 6 (the reception signal of one of the planar antenna elements 3), and the reception signal (measurement signal) of the reception antenna 2. And an input side switch 23 for switching whether to input to the signal input terminal.
Each of the planar antenna elements 3 is formed by pattern processing on a printed board having an area substantially the same as or larger than the object to be measured.
For example, the planar antenna element 3 of 8 rows and 8 columns is formed in an area of about 40 cm square on a printed circuit board with a center interval of about 5 cm. If a larger number of the planar antenna elements 3 are arranged at a narrower interval, it becomes possible to measure the electric field intensity distribution described later with higher resolution.
Here, if the gain of the planar antenna element 3 with respect to the frequency of the radio wave to be measured is optimized, the dimension is determined according to the measurement frequency. That is, the higher the measurement frequency, the shorter the wavelength of the radio wave, and the smaller the size of the planar antenna element 3. For this reason, it seems that the dimension of the planar antenna element 3 is determined by the measurement frequency. However, the distribution of the electric field strength of the received radio wave (signal strength distribution) is not an absolute value, but only a relative distribution can be measured. The dimensions of the planar antenna element 3 may be determined based on a balance between securing and the adverse effect of increasing the number of signals and increasing the processing load when the number of planar antenna elements 3 increases.

With the measuring device X as described above, the correspondence relationship between the transmitting antenna 1 and the receiving antenna 2 relative to the object to be measured, that is, the shift between the transmitting antenna corresponding area C1 and the receiving antenna corresponding area C2 is confirmed. be able to. This will be described below.
In addition, all the measurements for confirming the positional deviation described below are performed in a state where the object to be measured is not placed on the installation table 4.
First, before (or after) the measurement of the device under test, the output-side switch 21 is connected so that one of the two antennas 1 and 2 is connected to the output end (reference signal output end) of the vector network analyzer 7. , 22 and the input side switch 23 is switched so that the output of the multiplexer 6 is connected to the input terminal (measurement signal input terminal) of the vector network analyzer 7. This switching is performed, for example, by operating the computer 8 and outputting a switching signal to each of the switches 21 to 23 via the controller 9.
Next, the multiplexer 6 sequentially switches and selects which received signal of each of the planar antenna elements 3 is input to the vector network analyzer 7 (an example of signal switching means). The vector network analyzer 7 outputs the reference signal, receives a received signal from the planar antenna element 3, and sequentially measures the intensity of the received signal. The sequential switching of the planar antenna element 3 by the multiplexer 6 is performed by, for example, sequentially outputting a switching signal to the multiplexer 6 via the controller 9 by the computer 8.
Further, every time the computer 8 outputs a switching signal to the multiplexer 6, a switching completion signal is output to the vector network analyzer 7, and each time the signal is received, the vector network analyzer 7 Perform signal output and signal strength measurement based on the input signal. The measurement result of the signal strength is transferred to the computer 8.
Then, in the computer 8, a plurality of the planar antenna elements 3 as a whole are determined based on the signal strength of the received signal of each planar antenna element 3 measured by the vector network analyzer 7 and the arrangement position of each planar antenna element 3. The received radio wave intensity distribution (electric field intensity distribution) on the receiving surface (that is, the installation surface of the object to be measured (an example of a specific plane)) is determined (an example of an intensity distribution measuring unit).
Further, the computer 8 executes the above processing for each of the two antennas 1 and 2 and then calculates both measurement results of the intensity distribution in each case where radio waves are emitted from the two antennas 1 and 2. , Image and arrange (comparable) screen output (an example of intensity distribution comparison output means). For example, the received signal intensity of each of the planar antenna elements 3 is converted into logarithmic intensity (decibel conversion), and graphic display is performed with a color corresponding to the intensity.

FIG. 2 shows a screen output example of the image of the intensity distribution when each of the transmitting antenna 1 and the receiving antenna 2 is used, which is output to the screen of the computer 8. This example represents the result of observation of radio waves in the 6 GHz band using the planar antenna element 3 with the gain optimized for the radio waves in the 2.4 GHz band.
As shown in FIG. 2, when each of the transmitting antenna 1 and the receiving antenna 2 is used, coordinate display corresponding to the arrangement position of each of the planar antenna elements 3 is performed, and each of the installation surfaces of the object to be measured is displayed. The distribution of the electric field strength (signal strength) at the coordinates imaged by color coding or the like is displayed side by side.
The electric field intensity distribution for each of the two antennas 1 and 2 displayed in this way is a radio wave irradiation area corresponding to each of the two antennas 1 and 2 (the transmitting antenna corresponding area C1 and the receiving antenna corresponding area C2). ). Therefore, the user can check at a glance the deviation of the correspondence relationship between the positioning of the transmitting antenna 1 and the receiving antenna 2 with respect to the object to be measured.
Referring to the comparison output of the electric field intensity distribution as shown in FIG. 2, since the deviation between the two antennas 1 and 2 can be confirmed, one or both of the two antennas 1 and 2 are eliminated so as to eliminate the deviation. It becomes easy to finely adjust the position and direction.

Here, the measurement apparatus X includes a driving mechanism (or a driving mechanism) that drives the flexible support portion 10a (or 10b) of one of the two antennas 1 and 2 (in FIG. 1, the transmission antenna 1) according to an external control signal. And a controller 9 that receives a setting signal for adjusting the antenna direction from the computer 8 and outputs a control signal according to the setting signal to the flexible support portion 10a.
In the measuring apparatus X, the electric field intensity distribution (measurement result by the intensity distribution measuring means) in each case where radio waves are emitted from the two antennas 1 and 2 by the computer 8 is compared, and the radio wave irradiation area A deviation amount corresponding to a deviation (an area deviation having a relatively high signal intensity) is output to the controller 9. On the other hand, the controller 9 drives the flexible support portion 10a of one antenna (for example, the transmission antenna 1) in a direction to correct the deviation amount.
As a result, the orientation of one antenna 1 is automatically adjusted so that the deviation between the radio wave irradiation areas of the two antennas 1 and 2, that is, the deviation between the transmission antenna corresponding area C 1 and the reception antenna corresponding area C 2 is corrected. (An example of antenna position automatic adjustment means).
As the deviation amount, for example, for each case where the two antennas 1 and 2 are used, the center or reception of the area having the highest signal strength (electric field strength) in the electric field strength distribution is obtained. It is conceivable to use a deviation amount of the center of gravity in each of the x direction and the y direction. Alternatively, in each of the above cases, each area in which the signal intensity exceeds a preset set intensity in the electric field intensity distribution is obtained, and one area is set to x so that the area of the non-overlapping area of both areas is minimized. It is also conceivable to use the shift amount when shifted in the direction and the y direction.

In the measuring apparatus X, the multiplexer 6 sequentially switches and selects the received signals of the plurality of planar antenna elements 3, and measures the electric field strength distribution based on each of the sequentially selected signal strengths. In this measurement, the one-input vector network analyzer 7 used for measuring the object to be measured can also be used, and the electric field strength distribution measurement can be realized with a simple configuration.
Further, when the radio wave to be used is considered to be both a TM wave (a magnetic field is transverse to the traveling direction) and a TE wave (an electric field is transverse to the traveling direction), the planar antenna element 3 is formed at the time of switching. This can be dealt with by rotating the substrate (the mounting table 4) 90 °.
In addition, both the planar antenna element corresponding to the TM wave and the planar antenna element corresponding to the TE wave are pattern printed on the substrate, and which antenna element is used according to the type of radio wave to be used. It is good also as a structure which switches electrically.

When the measurement and the positional deviation adjustment for checking the positional deviation of the antenna are completed as described above, the output side switch is connected to connect the transmitting antenna 1 to the output end (reference signal output end) of the vector network analyzer 7. 21 and 22 and switching the input side switch 23 so that the receiving antenna 2 is connected to the input end (measurement signal input end) of the vector network analyzer 7, and then measuring the radio wave absorption characteristics of the object to be measured. I do.
At that time, the operation of the multiplexer 6 opens all the feeding ports of the planar antenna elements 3. As a result, the surface of the substrate on which the planar antenna element 3 is formed (the surface of the installation table 4) can be regarded as substantially equivalent to a metal plate in terms of radio wave reflection characteristics, and the measurement signal for the object to be measured It can be used as a reference plane for obtaining reference data for comparison.

In the configuration shown in FIG. 1, the output side switches 21 and 22 are provided in order to switch which of the two antennas 1 and 2 emits radio waves. It does not matter even if it is switched by inserting and removing possible connectors.
Further, in the configuration shown in FIG. 1, the automatic adjustment of the antenna misalignment is to adjust only the direction of the transmitting antenna 1, but is not limited to this, only the receiving antenna 2 or both antennas. A configuration in which the direction of 1 or 2 or the position thereof is adjusted in some cases is also conceivable.
Further, in the configuration shown in FIG. 1, the electric field strength distribution is measured by the received signals from the plurality of planar antenna elements 3 arranged. However, one or a plurality of planar antenna elements are driven by an actuator. A configuration is also conceivable in which the surface of the installation table 4 is scanned by an XY stage, the signal intensity of the received signal is measured each time the position is changed, and the electric field strength distribution on the surface of the installation table 4 is measured from the measurement result. . Such a configuration is more complicated than the measurement apparatus X and is inferior in terms of durability by the presence of the drive unit (scanning unit), but can be realized.

By the way, in the above-mentioned embodiment, since the object to be measured is an extremely thin plate-like object, the surface of the fixed installation table 4 is measured at the measurement position (on the installation table 4). It was a plane near the plane including the measurement surface of the object.
However, when the thickness of the object to be measured is large, the difference in position between the measurement surface of the object to be measured arranged on the installation table 4 and the surface of the fixed installation table 4 becomes large, and the antenna is accurately aligned. Can not be.
In such a case, for example, a device provided with an elevating mechanism (moving mechanism for the installation table) for raising and lowering the installation table 4 can be considered. Thereby, the measurement of the radio wave absorption characteristic is performed in a state in which the object to be measured is placed (placed) on the installation table 4 positioned at a predetermined reference position by the lifting mechanism, while the antenna alignment is performed as described above. With the elevating mechanism, the installation table 4 is raised from the reference position by the thickness of the object to be measured, that is, the surface of the installation table 4 (arrangement surface of the planar antenna element 3) is arranged at the measurement position. Further, the measurement can be performed in a state in which the measured object is positioned on a plane including the measurement surface (an example of a specific plane). Then, even when the thickness of the object to be measured is large, the measurement surface of the object to be measured at the time of measuring the radio wave absorption characteristics and the surface of the mounting table 4 at the time of positioning the antenna are almost flush with each other. Accurate alignment is possible.

  The present invention can be used for a radio wave absorption characteristic measuring apparatus.

The figure showing the schematic structure of the electromagnetic wave absorption characteristic measuring apparatus X which concerns on embodiment of this invention. The figure showing the example of a screen of the result of having output the radio wave intensity distribution in the installation surface of the to-be-measured object measured with the radio wave absorption characteristic measuring apparatus X as an image. The figure which represented typically the correspondence of the radio wave irradiation area with respect to the to-be-measured object of a transmitting antenna and a receiving antenna. The figure which represented the radio wave absorption characteristic measuring method typically.

Explanation of symbols

X ... Radio wave absorption characteristic measuring apparatus C1 ... Radio wave irradiation area C2 by transmission antenna ... Radio wave irradiation area 1 by reception antenna 1 ... Transmission antenna 2 ... Reception antenna 3 ... Planar antenna element 4 ... Installation base 5 of measurement object ... Line 6 ... Multiplexer 7 ... Vector network analyzer 8 ... Computer 9 ... Controllers 10a, 10b ... Flexible supports 21, 22, 23 ... Switches

Claims (6)

Each of the two antennas is supported so that the position of the antenna can be adjusted, the object to be measured is irradiated with a radio wave from one antenna, and the radio wave of the object to be measured is obtained based on a measurement signal obtained by causing the reflected radio wave to enter the other antenna. A radio wave absorption characteristic measuring device for measuring absorption characteristics,
Radio wave output switching means for switching which of the two antennas emits radio waves;
A radio wave absorption characterized by comprising intensity distribution measuring means for measuring the intensity distribution of a received radio wave in a specific plane which is a plane including the measurement surface of the object to be measured arranged at a measurement position or a plane in the vicinity thereof Characteristic measuring device. A plurality of planar antenna elements arranged in a plane,
2. The intensity distribution measuring means measures intensity distribution of received radio waves on reception surfaces of the plurality of planar antenna elements based on reception signals by the planar antenna elements arranged on the specific plane. The radio wave absorption characteristic measuring device described. Antenna position adjusting means for adjusting the position and / or orientation of one or both of the two antennas;
Intensity distribution comparison output means for outputting both measurement results by the intensity distribution measurement means in each case where radio waves are emitted from each of the two antennas;
The radio wave absorption characteristic measuring device according to claim 1, comprising:   Automatic antenna position adjustment for automatically adjusting the position and / or orientation of one or both of the two antennas based on comparison of measurement results by the intensity distribution measuring means in each case where radio waves are emitted from the two antennas. The radio wave absorption characteristic measuring apparatus according to claim 1 or 2, comprising means. Comprising signal switching means for sequentially switching and selecting received signals of each of the planar antenna elements;
5. The intensity distribution measuring means measures the intensity distribution of received radio waves on the receiving surfaces of the plurality of planar antenna elements based on the respective signal intensities sequentially selected by the signal switching means. The electromagnetic wave absorption characteristic measuring device according to claim 1. A vector network analyzer for outputting a reference signal for emitting a radio wave to one of the two antennas and measuring a signal change by inputting a measurement signal received by the other antenna;
6. The radio wave absorption characteristic measuring apparatus according to claim 5, wherein the intensity distribution measuring means also serves as the vector network analyzer for measuring signals sequentially selected by the signal switching means.

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