JP4944636B2 - Linear array antenna near-radiation electric field measurement apparatus and method - Google Patents

Description

  The present invention relates to an apparatus and a method for measuring the electric field strength in the vicinity of radiation of a linear array antenna.

Linear array antennas are often used as antennas for mobile phone radio base stations. When the base station antenna is installed on the antenna tower or building roof, information on the boundary that matches the reference value of the strength of the radio wave stipulated by the Radio Law is required.
FIG. 12 is a diagram illustrating a configuration example of an electric field measurement apparatus 600 in the vicinity of antenna radiation according to a conventional technique. FIG. 13 is an example of a processing flow.
In this measurement method, the electric field strength on the XY plane is measured in an arbitrary range, and the electric field strength on the XZ plane is calculated and estimated from the measurement result. Therefore, it is possible to grasp the electric field strength in the distance on the XZ plane from the electric field strength near the antenna on the XY plane.

The electric field measurement apparatus 600 includes an electric field sensor 10, a sensor positioning unit 610, an amplitude / phase detection circuit 30, a Fourier transform circuit 40, a Z-axis conversion circuit 50, an inverse Fourier transform circuit 60, and a display circuit 70.
For each axis, the axis parallel to the central axis of the linear array antenna is the X axis, the normal direction from the midpoint of the central axis of the linear array antenna to the X axis is the Z axis, and the X axis and Z axis An axis orthogonal to both axes is defined as the Y axis.
The electric field sensor 10 detects a high-frequency electric field including the X-axis component and the Y-axis component excited by the linear array antenna to be measured and outputs it as an electrical signal (S91).

The sensor positioning unit 610 moves the electric field sensor 10 on the XY plane based on a predetermined measurement range and a predetermined measurement interval in the X-axis direction and the Y-axis direction, and the X-axis coordinate value of the electric field sensor 10 at the measurement point. The x and Y axis coordinate values y are output (S93).
The amplitude / phase detection circuit 30 receives the electric signal output from the electric field sensor 10 and the coordinate values x and y of each measurement point output from the sensor positioning means 20, and the X axis of the high-frequency electric field for each measurement point. The component amplitude measurement data E _xa and phase measurement data P _xa , and the Y-axis component amplitude measurement data E _ya and phase measurement data P _ya are generated and output (S92).
Fourier transform circuit 40, amplitude / phase _E xa output from the detection circuit _{30, P xa, E ya,} P ya is input, calculates the X-axis component _{f x} and Y-axis component _{f y} wavenumber spectrum by the following equation (S94).

Here, a and b are measurement range lengths in the X-axis direction and the Y-axis direction, respectively. Further, E _X ′ and E _y ′ are electric field vectors, E _X ′ is an X-axis component whose elements are amplitude E _xa and phase P _xa , and E _y ′ is a Y-axis whose elements are amplitude E _ya and phase P _ya It is an ingredient. K _x and k _y are an X-axis component and a Y-axis component of the wave number, respectively.

Z-axis conversion circuit 50 is inputted and _{f x} and _{f y} output from the Fourier transform circuit 40 performs Z-axis converted by the following equation, and outputs the conversion result epsilon _x and ε _y (S95).

The inverse Fourier transform circuit 60 receives ε _x and ε _y output from the Z-axis transform circuit 50, and the X-axis component E _x , Y-axis component E _y, and Z-axis component of the electric field strength on the XZ plane according to the following equations: _Ez is calculated and output (S96).

The display circuit 70 receives E _x , E _y, and E _z output from the inverse Fourier transform circuit 60, and displays the electric field strength distribution on a screen or the like based on these (S97).
CABalanis, “ANTENNA THEORY 2nd ed.”, John Wiley & Sons Inc., 1982

According to the method according to the prior art, the electric field strength data in the Z-axis space can be estimated without measuring the Z-axis space.
However, in order to accurately calculate and estimate the electric field strength up to a distant region including the radiation vicinity region, the electric field strength on the XY plane needs to be measured further along the X and Y axes.
Further, when the measurement is performed with the same number of points in each axis direction, if the number of measurement points is increased in order to improve estimation accuracy, the number of measurement points is increased by the square.
As described above, the method according to the prior art has a problem that the measurement operation increases when the estimation accuracy is improved.

A linear array antenna radiation near-field electric field measuring device according to the present invention includes an electric field sensor, a sensor positioning means, an amplitude / phase detection circuit, an amplitude extrapolation arithmetic circuit, a phase extrapolation arithmetic circuit, an XY plane electric field data generation circuit, a Fourier transform circuit, a Z It consists of an axis conversion circuit, an inverse Fourier transform circuit, and a display circuit.
The electric field sensor detects a high-frequency electric field including an X-axis component and a Y-axis component excited by the linear array antenna, and outputs it as an electric signal.
The sensor positioning means moves the electric field sensor along the X axis within a predetermined measurement range and a predetermined measurement interval, and outputs an X-axis coordinate value of the electric field sensor. That is, the measurement is performed only on the X-axis (y = 0), and the measurement of the other regions (y ≠ 0) is not performed.

The amplitude / phase detection circuit receives the electrical signal and the X-axis coordinate value, and detects and outputs the amplitude measurement data and phase measurement data of the high-frequency electric field for each predetermined measurement interval in the predetermined measurement range. To do.
The amplitude extrapolation calculation circuit receives the amplitude measurement data, obtains a function of x and amplitude from the amplitude measurement data corresponding to the X-axis coordinate value x, and uses the function to obtain a function outside the predetermined measurement range. Then, the amplitude is estimated at predetermined intervals for a predetermined range on the X axis, and the estimation result is output as X axis amplitude data together with the amplitude measurement data. That is, the measurement is limited to a specific range close to the length of the antenna, and the estimation data is inserted without performing the measurement outside the measurement range.

The phase extrapolation calculation circuit receives the phase measurement data, obtains a function of x and phase from the X-axis coordinate value x and the corresponding phase measurement data, and uses the function to move outside the predetermined measurement range. Then, the phase is estimated at predetermined intervals for a predetermined range on the X axis, and the estimation result is output as X axis phase data together with the phase measurement data. That is, the measurement is limited to a specific range close to the length of the antenna, and the estimation data is inserted without performing the measurement outside the measurement range.
The XY plane electric field data generation circuit receives the X-axis amplitude data and the X-axis phase data. The y-axis electric field data is set to the X-axis amplitude data and the X-axis phase data when y = 0, and y ≠ The range of 0 is obtained as zero and output.

The Fourier transform circuit receives the electric field data of the XY plane, and calculates and outputs the wave number spectrum by Fourier transform.
The Z-axis conversion circuit receives the wave number spectrum and outputs a Z-axis conversion value obtained by multiplying a function including the value of the Z-axis coordinate value z.
The inverse Fourier transform circuit receives the Z-axis transformed value, and obtains and outputs XZ plane electric field data by inverse Fourier transform.
The display circuit receives the XZ plane data and displays the electric field strength distribution based on this data.

In the linear array antenna near-field electric field measurement apparatus according to the present invention, measurement is performed only on the X axis, and the measurement range is limited to a specific range close to the length of the antenna.
For this reason, the measurement time can be greatly shortened compared to the conventional two-dimensional measurement on the XY plane, and the measurement can be performed even in a small anechoic chamber.

[First Embodiment]
FIG. 1 is a diagram illustrating a configuration example of an electric field measurement apparatus 100 in the vicinity of antenna radiation according to the present invention.
The electric field measurement apparatus 100 includes an electric field sensor 10, a sensor positioning unit 20, an amplitude / phase detection circuit 30, an amplitude extrapolation arithmetic circuit 110, a phase extrapolation arithmetic circuit 120, an XY plane electric field data generation circuit 130, a Fourier transform circuit 40, and a Z An axis conversion circuit 50, an inverse Fourier transform circuit 60, and a display circuit 70 are included. The electric field sensor 10, the amplitude / phase detection circuit 30, the Fourier transform circuit 40, the Z-axis transform circuit 50, the inverse Fourier transform circuit 60, and the display circuit 70 have the same configuration as the prior art shown in FIG. Therefore, in FIG. 1, portions corresponding to those in FIG. The same applies to other drawings.

The sensor positioning means 20 moves the electric field sensor 10 on the X axis within a predetermined measurement range and a predetermined measurement interval, and sets the X axis coordinate value x and the Y axis coordinate value y = 0 of the electric field sensor 10 at the measurement point. Output.
The conventional technique for estimating the electric field distribution on the XZ plane is a method that requires measured values of the amplitude and phase of the electric field on the XY plane. This estimation method can be applied to any antenna.
However, linear array antennas that are often used as antennas for mobile phone radio base stations have antenna elements arranged in a straight line on the X axis. In such a case, the electric field of a certain XZ plane is estimated. In this case, the electric field distribution on the XY plane other than y = 0, that is, the electric field distribution when y ≠ 0 may be regarded as zero.

Therefore, in the present invention, with the primary purpose of speeding up the measurement of the electric field strength of the linear array antenna, the electric field distribution on the XZ plane is estimated by measuring the electric field strength only on the X axis.
The measurement range on the X axis depends on the length of the linear array antenna to be measured. Specifically, it is sufficient to measure twice the antenna length. Further, it is considered that the accuracy of estimation can be improved as the interval between the measurement points in the measurement range is fine, but it is considered that about λ / 2 (half wavelength) is optimal from the trade-off with the measurement operation. For example, when measuring a 1 m linear array antenna at a frequency of 2 GHz, the measurement range is 2 m (± 1 m from the antenna midpoint), and the measurement interval is 0.075 m because λ = 0.15 m. Accordingly, in this case, measurement is performed at 28 measurement points.

Further, the distance between the linear array antenna and the electric field sensor is preferably between λ / 2 and 2λ, and λ is considered to be the most desirable distance.
First, the amplitude extrapolation calculation circuit 110 outputs X-axis component amplitude measurement data _Exa and Y-axis component amplitude measurement data at a plurality of measurement point coordinates (x, 0) on the X-axis output from the amplitude / phase detection circuit 30. E _ya is input, and functions E _exa = f _ex (x) and E _eya = f _ey (x) are obtained from these. Then, for a predetermined range (extrapolation range) on the X axis that is outside the predetermined measurement range and required for estimating the electric field strength on the XZ plane by the functions f _ex (x) and f _ey (x), X-axis component amplitude extrapolation data E _exa and Y-axis component amplitude extrapolation data E _eya are calculated at predetermined intervals, and along with amplitude measurement data E _xa , E _ya , X-axis X component amplitude data E _{fxa (y = 0)} (= total data E _xa and E _exa), X-axis Y component amplitude data E _{fya (y =} 0) and outputs a (= total data E _ya and E _EYA). An image of such extrapolation is shown in FIG.

The calculation range on the X-axis required for estimation becomes wider in proportion to the length of the long side of the rectangle that defines the range of the XZ plane for which the electric field strength distribution is to be estimated, and the allowable estimation error is smaller. Become wider. Therefore, the calculation range may be determined according to the length of the long side of the rectangle that defines the range of the XZ plane for which the electric field intensity distribution is to be estimated and the allowable estimation error.
For example, when it is desired to measure the electric field intensity distribution on the XZ plane with an estimation error within ± 3 dB, the range about three times the length of the long side is desired, and when it is desired to measure with a measurement error within ± 1 dB, the long Extrapolation data is calculated for a range of about 5 times the length of the side.

More specifically, when the field intensity distribution in the XZ plane of −10 m to +5 m in the X direction and 0 to 20 m in the Z direction is required with reference to the X coordinate of the antenna middle point, and estimation is performed with an error of ± 1 dB In this case, 5 times the long side 20 m, that is, about 100 m is the calculation range of extrapolated data.
As for the interval between the calculation points, λ / 2 (half wavelength) is considered to be optimal, as is the case with the interval between the measurement points.
First, the phase extrapolation calculation circuit 120 first outputs X-axis component phase measurement data P _xa and Y-axis component phase measurement data at a plurality of measurement point coordinates (x, 0) on the X axis output from the amplitude / phase detection circuit 30. P _ya is inputted, and functions P _pxa = f _px (x) and P _pya = f _py (x) are _obtained from these. Then, with respect to a predetermined range (extrapolated range) on the X axis that is outside of the predetermined measurement range and required for estimating the electric field strength on the XZ plane by the functions f _px (x) and f _py (x), X-axis component phase extrapolation data P _pxa and Y-axis component phase extrapolation data P _pya are calculated at predetermined intervals, and X-axis X-component phase data P _{fxa (y = 0)} (with phase measurement data P _xa and P _{ya )} = All data of P _xa and P _pxa ), X-axis Y component phase data P _{fya (y = 0)} (= All data of P _ya and P _pya ) is output. An image of such extrapolation is shown in FIG.

The interval between the calculation range and the calculation point is the same as the setting content in the amplitude extrapolation calculation circuit 110.
The XY plane electric field data generation circuit 130 outputs the X-axis X component amplitude data E _{fxa (y = 0)} , the X-axis Y component amplitude data E _{fya (y = 0)} , and the phase output from the amplitude extrapolation calculation circuit 110. X-axis X component phase data P _{fxa (y = 0)} and X-axis Y component phase data P _{fya (y = 0)} output from the extrapolation calculation circuit 120 are input.
When estimating the electric field intensity on the XZ plane from the electric field intensity on the XY plane, in the case of a linear array antenna, the electric field distribution on the XY plane when y ≠ 0 may be regarded as 0 as described above. Therefore, in the present invention, measurement is not performed for the region where y ≠ 0, but the calculation processing for estimation is based on the premise that the region for y ≠ 0 shown in the background art is also measured (1) to ( Since the calculation is performed by the equation (3), it is necessary to input the value of the region where y ≠ 0 to the Fourier transform circuit 40. Therefore, in the XY plane electric field data generation circuit 130, measurement data E _{fxa (y = 0)} , E _{fya (y = 0)} , P _{fxa (y = 0)} , P on the input X axis, that is, y = 0. _{In addition to fya (y = 0)} , in the range of y ≠ 0 on the XY plane, E _{fxa (y ≠ 0)} = 0, E _{fya (y ≠ 0)} = 0, P _{fxa (y ≠ 0)} = 0, P Dummy data is generated with _{fya (y ≠ 0)} = 0, and these are combined and output as XY plane electric field data E _xa ′, E _ya ′, P _xa ′, and P _ya ′.

In the processing of the expression (1) in the Fourier transform circuit 40, for the electric field vectors E _X ′ and E _y ′, E _X ′ is an X-axis component whose elements are the amplitude E _xa ′ and the phase P _xa ′, E _y. The calculation is performed on the assumption that 'is a Y-axis component having the amplitude E _ya ' and the phase P _xa 'as elements.
It should be noted that the range of y for generating dummy data of y ≠ 0 set in estimating the electric field intensity on the XZ plane is the same value as the predetermined range on the X axis for convenience.
Accordingly, in equation (1), calculation is performed with b = a. Further, from this, the extrapolation calculation range on the X axis corresponding to the measurement range length a in the X axis in equation (1) is the length of the long side of the rectangle that defines the range of the XZ plane from which the electric field strength distribution is to be estimated. When set as L, the range of the XZ plane in which the electric field strength distribution is actually estimated is not a rectangle but an L × L square range.

A processing flow example in the first embodiment will be described with reference to FIG.
The electric field sensor 10 detects the high frequency electric field radiated from the linear array antenna (S1). Next, the amplitude / phase detection circuit 30 generates amplitude / phase measurement data for each of the X-axis component and the Y-axis component from the detected signal (S2). Here, if measurement of each measurement point in the predetermined measurement range is not completed, the electric field sensor 10 is moved by a predetermined distance in the X-axis direction by the sensor positioning means 20 (S3), and measurement in the predetermined measurement range is performed. Steps S3 → S1 → S2 →... Are repeated until is completed.

After the measurement of the predetermined measurement range is completed, the amplitude extrapolation calculation circuit 110 generates a function of the X-axis coordinate and the amplitude based on the amplitude measurement data of each measurement point output from the amplitude / phase detection circuit 30, and the function Is used to calculate amplitude data for a predetermined range (extrapolated range) on the X axis that is outside the measurement range and requires data for electric field estimation on the XZ plane. Then, a set of measured data and data calculated for extrapolation is output as amplitude data in a predetermined range on the X axis (S4).
Similarly to the amplitude extrapolation calculation circuit 110, the phase extrapolation calculation circuit 120 generates a function of X-axis coordinates and phase, and uses the function to estimate the phase of the XZ plane outside the measurement range. Therefore, phase data is calculated for a predetermined range (extrapolated range) on the X-axis that requires data for this purpose. Then, a set of measured data and data calculated for extrapolation is output as phase data in a predetermined range on the X axis (S5). Note that S4 and S5 can be processed in parallel.

Next, the XY plane electric field data generation circuit 130 generates XY plane electric field data for each of the extrapolated amplitude data and phase data (S6).
Next, the Fourier transform circuit 40 performs Fourier transform on the XY plane electric field data to calculate the wave number spectrum (S7).
Next, the Z-axis conversion circuit 50 determines the Z-axis conversion value by multiplying the wave number spectrum by the function of the Z-axis value z (S8).
Next, the inverse Fourier transform circuit 60 performs inverse Fourier transform on the Z-axis transformed value to calculate XZ plane electric field data (S9).

Finally, XZ plane electric field data is displayed on the display circuit 70 (S10).
As described above, since the measurement of the electric field is performed only on the X axis and the measurement range is limited to a narrow range close to the length of the antenna, the measurement time can be greatly shortened compared to the prior art, and Measurement in a small measurement space is also possible.

[Second Embodiment]
FIG. 4 is a diagram showing a configuration example of the electric field measurement apparatus 200 in the vicinity of the antenna radiation according to the present invention.
The electric field measurement device 200 is obtained by adding a rotation device 210 to the electric field measurement device 100.
The rotating device 210 has a function of rotating the linear array antenna about the central axis of the linear array antenna. Although the electric field intensity distribution on the XZ plane can be obtained in a plane by measuring the electric field on the X axis, the electric field measurement on the X axis and the rotation of the linear array antenna using this rotating device at an arbitrary angle are alternately performed. By doing so, it is possible to estimate a three-dimensional electric field strength distribution substantially over the entire circumference of the linear antenna.
By making the rotation angle finer, more detailed estimation is possible, but for practical use, it is considered sufficient to measure every 15 degrees (24 times / 360 °), for example.

A processing flow example in the second embodiment will be described with reference to FIG.
About S1-S10, since it is the same as that of 1st Embodiment, it abbreviate | omits.
After the measurement of a certain XZ plane data is completed, if the measurement of the predetermined number of planes is not completed, the rotation device 210 rotates the linear array antenna by a predetermined angle (S11), and the predetermined number of measurement planes are measured. Steps S11 → S1 to S10 →... Are repeated until the measurement is completed.

[Third Embodiment]
FIG. 6 is a diagram illustrating a portion of the electric field measurement apparatus 300 in the vicinity of the antenna radiation according to the present invention that is different from the electric field measurement apparatus 100.
In the configuration of the electric field measurement apparatus 100, the electric field measurement apparatus 300 includes two or more electric field sensors arranged on a circle centered on the central axis of the linear array antenna, and 1 from the output signal from each electric field sensor. An electric field sensor switching circuit 310 for selecting an output signal of each electric field sensor and outputting it is provided.
Although the electric field intensity distribution on the XZ plane can be obtained in a planar manner by measuring the electric field on the X axis, the electric field measurement on the X axis is performed by sequentially switching the electric field sensor switching circuit 310 for each of the plurality of electric field sensors. Similar to the second embodiment, it is possible to estimate a three-dimensional electric field strength distribution over substantially the entire circumference of the linear antenna.

More detailed estimation is possible by increasing the number of arranged electric field sensors, but it is considered that an arrangement of every 15 degrees (24 pieces / 360 °) is sufficient in practice.
An example of a processing flow in the third embodiment will be described with reference to FIG.
About S1-S10, since it is the same as that of 1st Embodiment, it abbreviate | omits.
After the measurement of certain XZ plane data is completed, if the measurement by all the sensors is not completed, the electric field sensor switching circuit 310 switches the electric field sensor used for the measurement (S12), and until the measurement by all the sensors is completed, S12. → S1 to S10 →...

[Fourth Embodiment]
FIG. 8 is a diagram illustrating a configuration example of the electric field measurement apparatus 400 in the vicinity of the antenna radiation according to the present invention.
The electric field measurement apparatus 400 is obtained by adding a calibration electric field sensor 410 and a calibration circuit 420 to the electric field measurement apparatus 100.
The calibration electric field sensor 410 is disposed on the XZ plane far from the electric field sensor 10 and within the range where the electric field strength is estimated as viewed from the central axis of the linear array antenna, and generates a high-frequency electric field excited by the linear array antenna. Detect and output electric field data.
The calibration circuit 420 receives the estimated XZ plane electric field data output from the inverse Fourier transform circuit 60 and the electric field data actually measured on the XZ plane by the calibration electric field sensor 410, and receives the XZ at the position of the calibration electric field sensor. A calibration coefficient is obtained from the difference between the surface estimation data and the actual measurement data, and each XZ surface estimation data is multiplied by the calibration coefficient and output.

By performing the calibration, the accuracy of the calculated electric field strength can be improved.
In order to perform calibration appropriately, a calibration electric field sensor 410 having a higher absolute accuracy than the electric field sensor 10 is used.
A processing flow example according to the fourth embodiment will be described with reference to FIG.
Since S1 to S10 are the same as those in the first embodiment, a description thereof will be omitted.
After the XZ plane electric field data is estimated in S9 or in parallel therewith, the calibration electric field data is detected by the calibration electric field sensor 410 installed in the estimated space range of the XZ plane electric field data (S13).
Next, the calibration circuit 420 obtains a calibration coefficient from the detected calibration electric field data and the estimated value of the XZ plane electric field data corresponding to the installation position of the calibration electric field sensor 410, and XZ plane electric field data is obtained from this calibration coefficient. Each estimated value is calibrated and output (S14).

[Fifth Embodiment]
FIG. 10 is a diagram showing a configuration example of the electric field sensor 510 in the electric field measurement apparatus 500 in the antenna radiation vicinity region of the present invention.
The electric field sensor 510 includes a laser diode 511, an optical demultiplexer 512, an X-axis micro dipole element 513, an X-axis Mach-Zehnder optical modulator 514, an X-axis photoelectric converter 515, a Y-axis micro dipole element 516, A Y-axis Mach-Zehnder optical modulator 517, a Y-axis photoelectric converter 518, and a support jig 519 are included.

  An optical signal emitted from the laser diode 511 is divided into two by an optical demultiplexer 512 and input to an X-axis Mach-Zehnder optical modulator 514 and a Y-axis Mach-Zehnder optical modulator 517, respectively. On the other hand, the voltages induced from the electric fields in the X-axis micro dipole element 513 and the Y-axis micro dipole element 516 arranged orthogonally by the support jig 519 are the X-axis Mach-Zehnder optical modulator 514 and the Y-axis Mach-Zehnder, respectively. Is input to the optical modulator 517. Then, in the Mach-Zehnder type optical modulator 514 for X-axis and the Mach-Zehnder type optical modulator 517 for Y-axis, the intensity of light is modulated by an induced voltage proportional to the electric field intensity, and the modulated optical signal is respectively converted to X-axis light. The electrical converter 515 and the Y-axis photoelectric converter 518 convert it to an electrical signal and output it as an X-axis component signal and a Y-axis component signal, respectively.

Since the Mach-Zehnder type optical modulator has a high input resistance and uses an optical fiber line, the influence on the electric field to be measured can be suppressed as much as possible. Moreover, the position resolution of a phase and an amplitude can be improved by using a micro dipole.
The length of the minute dipole is set to ¼ wavelength or less with respect to the wavelength of the radio wave to be measured.

<Measurement example to which the present invention is applied>
A measurement example of a 12-element vertical dipole linear array antenna in the 800 MHz band is shown in FIG. The length of the antenna is 2.5 m. The amplitude and phase of the electric field were measured on the X axis about one wavelength away from the antenna radiating element. The measured X-axis range is 6 m. The amplitude and phase of the electric field in the portion of ± 36 m of the broken line in FIG. 11 were extrapolated by the above method. The electric field strength in the range of ± 36 m on the y axis excluding y = 0 was all zero.
The calculation estimation result in the Z-axis direction shows the state of the main beam and sub beam of the antenna. Compared with the method of sweeping the electric field sensor two-dimensionally in the measurement of the radiation vicinity region, the present method sweeps the electric field sensor only on the X axis, so that the measurement time can be greatly shortened.

  The present invention is particularly useful for obtaining a boundary that matches the reference value of the intensity of radio waves defined by the Radio Law, which must be grasped at a radio base station of a mobile phone using a linear array antenna.

The structural example of the electric field measuring apparatus 100 by this invention. Image of extrapolation. The processing flow example using the electric field measuring apparatus 100 by this invention. The structural example of the electric field measuring apparatus 200 by this invention. The example of a processing flow using the electric field measuring apparatus 200 by this invention. The structural example which shows a different part with the electric field measurement apparatus 100 in the electric field measurement apparatus 300 by this invention. The example of a processing flow using the electric field measuring apparatus 300 by this invention. 3 shows a configuration example of an electric field measuring apparatus 400 according to the present invention. The processing flow example using the electric field measurement apparatus 400 by this invention. The structural example of the electric field sensor 510 in the electric field measuring apparatus 500 by this invention. The electric field strength distribution figure of the XZ plane in the measurement example to which this invention is applied. The structural example of the electric field measuring apparatus 600 by a prior art. The example of a processing flow using the electric field measuring apparatus 600 by a prior art.

Claims (9)

A linear array antenna radiation near-field electric field measurement device that measures the electric field intensity distribution around the linear array antenna using one or more electric field sensors in the vicinity of the linear array antenna,
For each electric field sensor, the axis parallel to the central axis of the linear array antenna is the X axis, the normal direction from the electric field sensor to the central axis of the linear array antenna is the Z axis, both the X axis and the Z axis The axis orthogonal to the Y axis is
The electric field sensor that detects a high-frequency electric field including an X-axis component and a Y-axis component excited by the linear array antenna and outputs an electric signal;
Sensor positioning means for moving the electric field sensor along the X axis and outputting an X axis coordinate value of the electric field sensor in a predetermined measurement range and a predetermined measurement interval;
An amplitude / phase detection circuit which receives the electrical signal and the X-axis coordinate value, and generates and outputs amplitude measurement data and phase measurement data of the high-frequency electric field at the predetermined measurement interval in the predetermined measurement range; ,
The amplitude measurement data is input, a function of x and amplitude is obtained from the amplitude measurement data corresponding to the X-axis coordinate value x, and the function is outside the predetermined measurement range and on the X-axis. An amplitude extrapolation calculation circuit that estimates an amplitude at predetermined intervals for a predetermined range and outputs the estimation result as X-axis amplitude data together with the amplitude measurement data;
The phase measurement data is input, a function of x and phase is obtained from the phase measurement data corresponding to the X-axis coordinate value x, and the function is outside the predetermined measurement range and on the X-axis. A phase extrapolation calculation circuit that estimates a phase at a predetermined interval for a predetermined range, and outputs an estimation result as X-axis phase data together with the phase measurement data;
The X-axis amplitude data and the X-axis phase data are input, and the electric field data on the XY plane is determined as the X-axis amplitude data and the X-axis phase data when y = 0, and the range of y ≠ 0 is determined as zero. Output XY plane electric field data generation circuit,
A Fourier transform circuit that inputs the XY plane electric field data and calculates and outputs a wave number spectrum by Fourier transform;
A Z-axis conversion circuit that receives the wavenumber spectrum and outputs a Z-axis conversion value obtained by multiplying this by a function including the value of the Z-axis coordinate value z;
An inverse Fourier transform circuit that receives the Z-axis transformation value and obtains and outputs XZ-plane electric field data by inverse Fourier transformation;
A display circuit that receives the XZ plane data and displays the electric field intensity distribution based on the data;
A linear array antenna near-radiation electric field measurement apparatus comprising: The linear array antenna near-field electric field measurement apparatus according to claim 1,
The linear array antenna radiation near-field electric field measuring device further comprising a rotating device that rotates the linear array antenna about the central axis of the linear array antenna. The linear array antenna near-field electric field measurement apparatus according to claim 1,
Two or more electric field sensors are arranged on a circle centered on the central axis of the linear array antenna,
A linear array antenna radiation near-field electric field measuring device further comprising an electric field sensor switching circuit for selecting an output signal of one electric field sensor from output signals of the two or more electric field sensors and outputting the selected signal. . The linear array antenna radiation vicinity electric field measurement apparatus according to any one of claims 1 to 3, further comprising:
A calibration electric field sensor that is installed farther from the electric field sensor as viewed from the central axis of the linear array antenna, detects a high-frequency electric field excited by the linear array antenna, and outputs electric field data;
A calibration circuit that inputs XZ plane electric field data from the inverse Fourier transform circuit and electric field data from the calibration electric field sensor, calibrates and outputs the XZ plane electric field data;
A linear array antenna radiation near electric field measuring device comprising: A linear array antenna radiation vicinity electric field measurement apparatus according to any one of claims 1 to 4,
The electric field sensor
A laser diode that generates and outputs an optical signal; and
An optical demultiplexer that receives the optical signal and demultiplexes the optical signal into two optical signals;
A micro dipole element for the X axis that detects the X axis component of the electric field;
Mach-Zehnder type for X-axis that receives one of the demultiplexed optical signals, modulates the phase of the optical signal with a voltage induced in the X-axis micro dipole element, and outputs the X-axis component modulated optical signal An optical modulator;
An X-axis photoelectric converter that receives the X-axis component modulated light signal and outputs an X-axis component signal obtained by converting the signal into an electrical signal;
A fine dipole element for Y-axis for detecting the Y-axis component of the electric field;
The other optical signal that has been demultiplexed is input, the phase of the optical signal is modulated with the voltage induced in the micro dipole element for Y axis, and the Y-axis Mach-Zehnder that outputs the Y-axis component modulated optical signal is output. Type optical modulator,
A Y-axis photoelectric converter that receives the Y-axis component modulated optical signal and outputs a Y-axis component signal obtained by converting the Y-axis component modulated optical signal;
A support jig for fixing the X-axis micro dipole element and the Y-axis micro dipole element in the X-axis direction and the Y-axis direction, respectively;
A linear array antenna radiation near electric field measuring device comprising: A linear array antenna radiation vicinity electric field measurement method for measuring an electric field intensity distribution around the linear array antenna using one or more electric field sensors in the vicinity of the linear array antenna,
For each electric field sensor, the axis parallel to the central axis of the linear array antenna is the X axis, the normal direction from the electric field sensor to the central axis of the linear array antenna is the Z axis, both the X axis and the Z axis The axis orthogonal to the Y axis is
The electric field sensor detecting a high-frequency electric field including an X-axis component and a Y-axis component excited by the linear array antenna and outputting the electric signal as an electric signal;
A sensor positioning means for moving the electric field sensor along the X axis in a predetermined measurement range and a predetermined measurement interval and outputting an X-axis coordinate value of the electric field sensor;
An amplitude / phase detection circuit generates and outputs amplitude measurement data and phase measurement data of the high-frequency electric field for each predetermined measurement interval in the predetermined measurement range from the electric signal and the X-axis coordinate value. When,
An amplitude extrapolation calculation circuit obtains a function of x and amplitude from the amplitude measurement data corresponding to the X-axis coordinate value x from the amplitude measurement data, and the function is outside the predetermined measurement range. Estimating the amplitude at predetermined intervals for a predetermined range on the X axis, and outputting the estimation result as X axis amplitude data together with the amplitude measurement data;
A phase extrapolation calculation circuit obtains a function of x and phase from the phase measurement data and the phase measurement data corresponding to the X-axis coordinate value x, and is outside the predetermined measurement range by the function. Estimating the phase at predetermined intervals for a predetermined range on the X axis, and outputting the estimation result as X axis phase data together with the phase measurement data;
An XY plane electric field data generation circuit uses the X-axis amplitude data and the X-axis phase data to change the XY plane electric field data to the X-axis amplitude data and the X-axis phase data when y = 0, and y ≠ 0. Obtaining and outputting the range as zero, and
A Fourier transform circuit calculates and outputs a wave number spectrum by Fourier transform from the electric field data of the XY plane;
A step in which the Z-axis conversion circuit outputs a Z-axis conversion value obtained by multiplying the wavenumber spectrum by a function including the value of the Z-axis coordinate value z;
An inverse Fourier transform circuit obtains and outputs XZ plane electric field data from the Z-axis transformed value by inverse Fourier transform;
A display circuit displaying an electric field intensity distribution based on the XZ plane data;
Linear array antenna radiation near-field electric field measurement method to perform. It is the linear array antenna radiation | emission near electric field measurement method of Claim 6, Comprising:
The linear array antenna radiation near-field electric field measurement method further comprising: executing a step of rotating the linear array antenna about the central axis of the linear array antenna. It is the linear array antenna radiation | emission near electric field measurement method of Claim 6, Comprising:
Two or more electric field sensors are arranged on a circle centered on the central axis of the linear array antenna,
Further, the electric field sensor switching circuit includes executing a step of selecting an output signal of one electric field sensor from the output signals of the two or more electric field sensors and outputting the selected signal. Electric field measurement method. It is the linear array antenna radiation | emission near electric field measurement method in any one of Claims 6-8, Comprising: Furthermore,
A calibration electric field sensor detecting a high-frequency electric field excited by the linear array antenna at a position farther than the electric field sensor when viewed from the central axis of the linear array antenna, and outputting electric field data;
A calibration circuit calibrating and outputting the XZ plane electric field data from the XZ plane electric field data from the inverse Fourier transform circuit and the measurement value of the calibration electric field sensor;
A linear array antenna radiation near-field electric field measurement method comprising:

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