JPWO2020129187A1 - Axial ratio measuring method and axial ratio measuring device - Google Patents

Abstract

With the output ports (13, 14) in the circularly polarized power feeding circuit (1) terminated without reflection, the reflection characteristics at the circularly polarized input ports (11, 12) are measured, and the output ports (13, 14) are measured. ) Is short-term terminated, the reflection characteristics at the input port (11) when the distance between the output port (13, 14) and the short-circuit termination position is changed are measured, and the measured values of these reflection characteristics are used. To calculate the axial ratio.

Description

The present invention relates to an axial ratio measuring method and an axial ratio measuring device for measuring the axial ratio of circularly polarized light.

For example, Patent Document 1 describes a conventional axial ratio measuring method for measuring the axial ratio of a circularly polarized antenna. In this axial ratio measurement method, the antenna under test, which is a circularly polarized antenna, is arranged at an appropriate distance in the main beam direction of the transmitting antenna that emits linearly polarized waves, and is radiated from the transmitting antenna into space. Receives linearly polarized light. The transmitting antenna is rotated by a rotating device in a plane perpendicular to the main beam direction. The maximum and minimum values of the received power measurement values are selected from the received power measurement values of the antenna under test that change periodically as the transmitting antenna rotates, and the difference between the selected maximum and minimum values is the axial ratio. Is calculated as.

Japanese Unexamined Patent Publication No. 6-094764

Since the axial ratio measuring method described in Patent Document 1 uses linearly polarized waves radiated into space from the transmitting antenna, there is a problem that the axial ratio measuring accuracy is easily affected by the surrounding environment.

The present invention solves the above problems, and an object of the present invention is to obtain an axial ratio measuring method and an axial ratio measuring device capable of reducing the influence of the ambient environment on the axial ratio measurement.

In the axial ratio measuring method according to the present invention, the reflection characteristic at the circularly polarized light input port in the circularly polarized light feeding circuit is measured in a state where the circularly polarized light output port in the circularly polarized light feeding circuit is non-reflective terminalized. Steps to measure the reflection characteristics at the input port when the distance between the output port and the short-circuit termination position is changed while the output port is short-circuited, and the output port is non-reflective terminated. It is provided with a step of calculating the axial ratio of circularly polarized light using the measured values of the reflection characteristics measured in each of the state where the output port is short-circuited and the state where the output port is short-term terminated.

According to the present invention, the reflection characteristics of the circularly polarized light input port are measured in the state where the circularly polarized output port in the circularly polarized power feeding circuit is non-reflectively terminated, and the output port is short-circuited. The reflection characteristics at the input port when the distance between the output port and the short-circuit termination position is changed are measured, and the axial ratio of circularly polarized light is calculated using the measured values of these reflection characteristics. Since the measured value of the reflection characteristic at the input port is used for the axial ratio measurement without using the radio wave propagating in space, the influence of the surrounding environment on the axial ratio measurement can be reduced.

It is a figure which shows the circularly polarized wave feeding circuit of the axial ratio measurement target. It is a block diagram which shows the structure of the circularly polarized light feeding circuit which connected the non-reflection terminator to an output port, and the axial ratio measuring apparatus which concerns on Embodiment 1. FIG. It is a block diagram which shows the structure of the circular polarization feeding circuit which output port short-circuited termination, and the axial ratio measuring apparatus which concerns on Embodiment 1. FIG. It is a flowchart which shows the axial ratio measurement method which concerns on Embodiment 1. It is a flowchart which shows the detailed process of step ST4 of FIG. It is a block diagram which shows the structure of the circularly polarized light feeding circuit whose output port is short-circuited, and the axial ratio measuring apparatus which concerns on Embodiment 2. FIG. It is a flowchart which shows the axial ratio measurement method which concerns on Embodiment 2. It is a flowchart which shows the detailed process of step ST2a of FIG. It is a block diagram which shows the structure of the circularly polarized light feeding circuit whose output port is short-circuited, and the axial ratio measuring apparatus which concerns on Embodiment 3. FIG. It is a flowchart which shows the axis ratio calculation process in the axis ratio measurement method which concerns on Embodiment 3. It is a block diagram which shows the structure of the circularly polarized light feeding circuit whose output port is short-circuited, and the axial ratio measuring apparatus which concerns on Embodiment 4. FIG. It is a flowchart which shows the axis ratio calculation process in the axis ratio measurement method which concerns on Embodiment 4.

Embodiment 1.
FIG. 1 is a diagram showing a circularly polarized wave feeding circuit 1 to be measured for an axial ratio. In FIG. 1, the circularly polarized light feeding circuit 1 is a power feeding circuit that feeds circularly polarized light to an antenna, and includes an input port 11, an input port 12, an output port 13, and an output port 14. The input port 11 is a port # 1 to which right-handed circularly polarized light (hereinafter referred to as RHCP) is input, and the input port 12 is a port to which left-handed circularly polarized light (hereinafter referred to as LHCP) is input. It is # 2. The output port 13 is the port # 3 to which the RHCP is output, and the output port 14 is the port # 4 to which the LHCP is output.

Although FIG. 1 shows a case where the circularly polarized wave feeding circuit 1 is a waveguide type, the axial ratio measurement target may be a circularly polarized wave feeding circuit other than the waveguide type. In a general waveguide type circularly polarized wave feeding circuit 1, the input port 11 and the input port 12 are separate square waveguides, and the output port 13 and the output port 14 are one circular waveguide. In many cases. Further, the output port 13 and the output port 14 may be a square waveguide. Hereinafter, the method of measuring the axial ratio of RHCP in the circularly polarized wave feeding circuit 1 will be described, but the measurement of the axial ratio of LHCP is also the same.

The scattering matrix of the circularly polarized power feeding circuit 1 includes parameters S ₁₁ , parameter S _44, and parameter S ₄₁ as elements. The parameter S ₁₁ is a parameter indicating the reflection characteristic at the input port 11 to which the RHCP is input, and the parameter S ₄₄ is a parameter indicating the reflection characteristic at the output port 14 to which the LHCP is output. The parameter S ₄₁ is a parameter corresponding to the cross polarization discrimination degree, and can be converted into the axial ratio of the circularly polarized wave feeding circuit 1. The cross-polarization discrimination degree is a degree at which RHCP and LHCP can be distinguished.

FIG. 2 is a block diagram showing a circularly polarized wave feeding circuit 1 in which a non-reflective terminator 20 is connected to output ports 13 and 14 and a configuration of an axial ratio measuring device according to the first embodiment. FIG. 3 is a block diagram showing a circularly polarized wave feeding circuit 1 in which the output ports 13 and 14 are short-circuited, and a configuration of an axial ratio measuring device according to the first embodiment. The axial ratio measuring device shown in FIGS. 2 and 3 is a device for measuring the axial ratio of circularly polarized light fed by the circularly polarized light feeding circuit 1, and includes a reflection measuring device 30 and an arithmetic unit 31. In FIG. 2, a non-reflective terminator 20 is connected to the output ports 13 and 14 of the circularly polarized wave feeding circuit 1. The non-reflective terminator 20 is, for example, a device in which an output port 13 and an output port 14 are short-circuited and a radio wave absorber is loaded.

In FIG. 3, a short-circuit plate 21 is connected to the output ports 13 and 14 of the circularly polarized wave feeding circuit 1. Further, the distance s between the output ports 13 and 14 and the position of the short-circuit plate 21 can be changed. For example, when the output ports 13 and 14 are circular waveguides or square waveguides, a waveguide having the same cross-sectional shape as the output port is mounted between the output ports 13 and 14 and the short-circuit plate 21. Therefore, the distance s can be changed. The waveguide mounted between the output ports 13 and 14 and the short-circuit plate 21 may have various lengths depending on the range in which the distance s is changed. Hereinafter, the position of the short-circuit plate 21 connected to the output ports 13 and 14 will be referred to as a short-circuit termination position.

The reflection measuring instrument 30 is, for example, a network analyzer, and as shown in FIG. 2, the reflection characteristics at the input port 11 are measured with the output ports 13 and 14 terminated without reflection, and the reflection characteristics at the input port 12 are measured. To measure. Here, the reflection characteristic at the input port 12 is approximated by the _{parameter S 44, which is an element of the scattering matrix.} Parameter S _{11 and parameter S 44,} which indicates the reflection characteristics at the input port 12, can be represented by complex numbers using amplitude and phase.
In the following description, it is assumed that only the amplitudes representing the _{parameters S 11} and S _{44 can be measured.}

As shown in FIG. 3, the reflection measuring device 30 measures the reflection characteristic at the input port 11 in a state where the output ports 13 and 14 are short-circuited, and measures the reflection characteristic at the input port 12. Further, with the output ports 13 and 14 short-circuited, the reflection measuring instrument 30 measures the reflection characteristics at the input port 11 when the distance s between the output ports 13 and 14 and the short-circuited termination position is changed. ..

The arithmetic unit 31 is, for example, a computer, and calculates the axial ratio of circularly polarized light using the measured value of the reflection characteristic measured by the reflection measuring device 30. _{For example, the arithmetic unit 31 has the maximum value S 11, s} of the measured values of the _{parameters S 11, s} indicating the reflection characteristics at the input port 11 measured by changing the distance s between the output ports 13 and 14 and the short-circuit end position. _{, Max , the measured value of the parameter S 11} indicating the reflection characteristic at the input port 11 and the measurement of the _{parameter S 44} indicating the reflection characteristic at the input port 12 measured in the state where the output ports 13 and 14 are non-reflective terminated. The value is subtracted, the subtracted value is divided by 2, and the parameter S ₄₁ is calculated, and the calculated parameter S ₄₁ is used to calculate the axial ratio of the RHCP.

Next, the operation will be described.
FIG. 4 is a flowchart showing the axial ratio measuring method according to the first embodiment.
The reflection measuring instrument 30 is a pair of input ports in which circularly polarized light having different turning directions is input in the circularly polarized light feeding circuit 1 with the output ports 13 and 14 in the circularly polarized light feeding circuit 1 being non-reflectively terminated. One of the measurement targets is set, and the reflection characteristics at the input port to be measured are measured (step ST1). Here, the input port pairs to which circularly polarized waves having different turning directions are input are the input port 11 and the input port 12. For example, it is assumed that the input port 11 is the measurement target. At this time, the input port 12 is non-reflectively terminated. That is, the reflection measuring device 30 measures the reflection characteristic at the input port 11 in a state where the non-reflective terminator 20 is connected to the output ports 13 and 14 and the non-reflective terminator is connected to the input port 12. As a result, the measured value _{of the parameter S 11 is obtained.}

Subsequently, the reflection measuring device 30 sets the other of the input port pair in the circularly polarized light feeding circuit 1 as the measurement target in a state where the output ports 13 and 14 in the circularly polarized power feeding circuit 1 are non-reflectively terminated, and sets the measurement target. The reflection characteristic at the input port is measured (step ST2). When the input port 11 is the measurement target in step ST1, in step ST2, the input port 12 to which the circularly polarized wave of the reverse rotation is input is the measurement target. At this time, the input port 11 is non-reflectively terminated. That is, the reflection measuring device 30 measures the reflection characteristic at the input port 12 in a state where the non-reflective terminator 20 is connected to the output ports 13 and 14 and the non-reflective terminator is connected to the input port 11. As a result, the measured value _{of the parameter S 44 is obtained.}

Next, the reflection measuring instrument 30 shifts to a loop process (step ST3) that is repeated for the number of values of the distance s. In this loop processing, the reflection measuring instrument 30 reflects at the input port to be measured with the distance s between the output ports 13 and 14 and the short-circuit termination position and the output ports 13 and 14 being short-circuited. The characteristics are measured (step ST3-1). When measuring the RHCP axial ratio, the input port to be measured is the input port 11. At this time, the input port 12 is non-reflectively terminated. That is, the reflection measuring device 30 measures the reflection characteristic at the input port 11 in a state where the output ports 13 and 14 are short-circuited and the non-reflective terminator is connected to the input port 12. As a result, the measured values of _{the parameters S11 and s} corresponding to the distance s can be obtained. When measuring the axial ratio of LHCP, the input port 12 is the measurement target.

Subsequently, the distance s is changed (step ST3-2). For example, when the output ports 13 and 14 are circular waveguides or square waveguides, a plurality of waveguides having the same cross-sectional shape as the output port but different in length are prepared. By mounting these waveguides in order between the output ports 13 and 14 and the short-circuit plate 21, the distance s changes. Although it is assumed that the waveguide is installed manually, it may be installed automatically by using a drive mechanism. The range of the distance s is set so that the measurement frequency is 0 to half a wavelength. In the loop processing of step ST3, the parameters S11 and s corresponding to the number of values of the changed distance _s are measured.

The arithmetic unit 31 calculates the axial ratio using the measured values of the parameters obtained by the reflection measuring device 30 (step ST4). The axial ratio calculated by the arithmetic unit 31 is output to, for example, a display device (not shown in FIGS. 2 and 3) and presented to the user.
Arithmetic unit 31 was measured by the reflection measuring unit 30, the parameter _{S 11,} the parameter _{S 44,} and, using the parameters _{S 11, s} to the number of all the values of the distance s of varying, calculated axial ratio of RHCP To do.

Next, the details of the axial ratio calculation process by the arithmetic unit 31 will be described.
FIG. 5 is a flowchart showing the detailed processing of step ST4 of FIG.
The arithmetic unit 31 determines the maximum values S11 _{, s, max from the measured values of the plurality of parameters S11, s} measured by the reflection measuring device 30 by changing the distance s between the output ports 13 and 14 and the short-circuit end position. Sort (step ST1a). For example, the arithmetic unit 31 selects the maximum values S _{11, s, max from the parameters S 11, s corresponding} to the number of values of the changed distance s.

The parameters S _{11 and s} can be expressed by the following equation (1) using the parameters S ₁₁ and S _44. In the following equation (1), β is a propagation constant of the waveguide up to the short-circuit plate 21, and is assumed to be a known value.
S _{11, s} = S ₁₁ + 2S ₄₁ e ^−j2βs + S ₄₄ e ^−j4βs・ ・ ・ (1)

Next, the arithmetic unit 31 uses _{the measured value of the parameter S 11 and} the measured value of the parameter S ₄₄ measured by the reflection measuring device 30 and the maximum values S _{11, s, max} to determine the cross polarization discrimination degree. The corresponding parameter S ₄₁ is calculated (step ST2a). In the above equation (1), when the range of the distance s to be changed is set to be 0 to half a wavelength at the measurement frequency, the maximum value S _{11, s, max} ^{at the distance s such that e −j2βs} = e− ^{j4βs = 1.} Is obtained, and the maximum values S11 _{, s, max} can be expressed by the following equation (2).
S _{11, s, max} = S ₁₁ + 2S ₄₁ + S ₄₄ ... (2)

Since the parameter S ₁₁ and the parameter S ₄₄ have already been measured by the reflection measuring device 30, the parameter S ₄₁ can be calculated from the following equation (3). The parameters S ₁₁ , the parameters S _44, and the parameters S _{11, s} are represented by complex numbers using the phase and the amplitude, but the reflection measuring instrument 30 does not need to measure the phase representing these parameters, and only the amplitude is measured. Measure.
S ₄₁ = (S _{11, s, max-} S _11- S ₄₄ ) / 2 ... (3)

The arithmetic unit 31 calculates the _{parameter S 41 by substituting the values of the parameters S 11} and S ₄₄ and the maximum values S _{11, s, max} measured by the reflection measuring device 30 into the above equation (3).
_{After that, the arithmetic unit 31 substitutes the parameter S 41} calculated using the above equation (3) into the following equation (4) to calculate the axial ratio AR (step ST3a).
AR = (1 + S ₄₁ ) / (1-S ₄₁ ) ... (4)

As described above, in the axial ratio measuring method according to the first embodiment, reflection at the circularly polarized input ports 11 and 12 is performed in a state where the output ports 13 and 14 in the circularly polarized power feeding circuit 1 are non-reflectively terminated. Reflection at the input port 11 when the distance s between the output ports 13 and 14 and the short-circuit termination position is changed while the output ports 13 and 14 are short-term terminated by measuring the _{parameters S 11} and S ₄₄ indicating the characteristics. _{The parameters S11 and s} indicating the characteristics are measured, and the axial ratio AR of circularly polarized light is calculated from the measured values of these parameters. Since the measured values of the reflection characteristics at the input ports 11 and 12 are used for the axial ratio measurement without using the radio waves propagating in space, the influence of the surrounding environment on the axial ratio measurement can be reduced. The parameter S _11, it is unnecessary to measure the phase representing the parameters S ₄₄ and the parameter S _{11, s,} it can be determined axial ratio only in the measurement of the amplitude.

Embodiment 2.
FIG. 6 is a block diagram showing the configuration of the circularly polarized wave feeding circuit 1 in which the output ports 13 and 14 are short-circuited and the axial ratio measuring device according to the second embodiment. The axial ratio measuring device shown in FIG. 6 is a device for measuring the axial ratio of the circularly polarized light of the circularly polarized light feeding circuit 1, and includes a reflection measuring device 30A and an arithmetic unit 31A. Hereinafter, the method of measuring the axial ratio of RHCP in the circularly polarized wave feeding circuit 1 will be described, but the measurement of the axial ratio of LHCP is also the same.

Similar to FIG. 3, a short-circuit plate 21 is connected to the output ports 13 and 14, and the distance s between the output ports 13 and 14 and the position of the short-circuit plate 21 can be changed. For example, when the output ports 13 and 14 are circular waveguides or square waveguides, a waveguide having the same cross-sectional shape as the output port is mounted between the output ports 13 and 14 and the short-circuit plate 21. Therefore, the distance s can be changed. The waveguide mounted between the output ports 13 and 14 and the short-circuit plate 21 may have various lengths depending on the range in which the distance s is changed.

The reflection measuring instrument 30A is, for example, a network analyzer. Since the axial ratio of the RHCP is measured, the reflection measuring instrument 30A is the input port 11 when the distance s between the output ports 13 and 14 and the short-circuit termination position is changed while the output ports 13 and 14 are short-circuited. The reflection characteristics of each are measured. When measuring the axial ratio of the LHCP, the reflection measuring device 30A inputs when the distance s between the output ports 13 and 14 and the short-circuited termination position is changed while the output ports 13 and 14 are short-circuited. The reflection characteristics at the port 12 are measured respectively.

The arithmetic unit 31A is, for example, a computer, and calculates the axial ratio of circularly polarized light using the measured value of the reflection characteristic measured by the reflection measuring device 30A. _{For example, the arithmetic unit 31A has parameters S 11 and s} indicating the reflection characteristics at the input port 11 measured when the distance s between the output ports 13 and 14 and the short-circuit termination position is changed by the reflection measuring device 30A. from the measured values, the average value S _{11, ave} of these measurements is subtracted respectively, to calculate the parameter S ₄₁ the difference is a value obtained by dividing by four the maximum value and the minimum value of the subtracted value is calculated The axial ratio of the RHCP is calculated using the parameter S _41.

Next, the operation will be described.
FIG. 7 is a flowchart showing the axial ratio measuring method according to the second embodiment.
The reflection measuring instrument 30A executes a loop process (step ST1b) that is repeated for the number of values of the distance s. In this loop processing, the reflection measuring instrument 30A reflects at the input port to be measured with the distance s between the output ports 13 and 14 and the short-circuit termination position and the output ports 13 and 14 being short-circuited. The characteristics are measured (step ST1b-1).

When measuring the RHCP axial ratio, the input port to be measured is the input port 11. At this time, the input port 12 is non-reflectively terminated. That is, the reflection measuring device 30A measures the reflection characteristic at the input port 11 in a state where the output ports 13 and 14 are short-circuited and the non-reflective terminator is connected to the input port 12. As a result, the measured values of _{the parameters S11 and s} corresponding to the distance s can be obtained. When measuring the axial ratio of LHCP, the input port 12 is the measurement target.

Subsequently, the distance s is changed (step ST1b-2). For example, when the output ports 13 and 14 are circular waveguides or square waveguides, a plurality of waveguides having the same cross-sectional shape as the output port but different in length are prepared. By mounting these waveguides one by one between the output ports 13 and 14 and the short-circuit plate 21, the distance s changes. Although it is assumed that the waveguide is installed manually, it may be installed automatically by using a drive mechanism. The range of the distance s to be changed is set so as to be 0 to half a wavelength at the measurement frequency. In the loop processing of step ST1b, the parameters S11 and s corresponding to the number of values of the changed distance _s are measured.

The arithmetic unit 31A calculates the axial ratio using the measured values of the parameters obtained by the reflection measuring device 30A (step ST2b). The axial ratio calculated by the arithmetic unit 31A is output to, for example, a display device (not shown in FIGS. 2 and 3) and presented to the user.
Arithmetic unit 31A was measured by reflectometry instrument 30A, the parameter _{S 11,} the parameter _{S 44,} and calculates the axial ratio by using the parameter _{S 11, s} to the number of all the values of the distance s was changed.

Next, the details of the axis ratio calculation process by the arithmetic unit 31A will be described.
FIG. 8 is a flowchart showing the detailed processing of step ST2b of FIG.
The arithmetic unit 31A uses the following equation (5) to change the distance s between the output ports 13 and 14 and the short-circuit end position, and the average value of the measured values of _{the plurality of parameters S 11 and s S 11, ave.} Is calculated (step ST1c). In the following equation (5), N is the number of measured values of the _{parameters S11 and s.}
S _{11, ave} = (ΣS _{11, s} ) / N ... (5)

Since the second and third terms of the right side of the equation (1) is 0, the average value _{S 11, ave} is approximated by the parameter _{S 11.} The parameters S _{11 and s} are represented by a complex number using the phase and amplitude measured by the reflection measuring device 30A, and the average is calculated as the complex number. It is possible to measure the relative phase when the distance s is changed. Average _{S 11, ave} is, since it is approximated by the parameter _{S 11,} the following equation using the equation (1) (6) is obtained.
S _{11, s-} S _{11, ave} = 2S ₄₁ e- ^j2βs + S ₄₄ e- ^j4βs
... (6)

The arithmetic unit 31A subtracts the average values _{S11 and ave from the plurality of parameters S11 and s} measured by changing the distance s, respectively, and from the plurality of values obtained by the subtraction, the maximum value max (S11, S11 _{, s-} S _{11, ave} ) and the minimum value min (S _{11, s-} S _{11, ave} ) are selected (step ST2c).

^{The phase rotation angle of e−j4βs in} the second term on the right side of the above equation (6) is twice the phase rotation angle of e− ^j2βs in the first term. For example, ^when the phase rotation angle of e−j2βs is from 0 degrees to 180 degrees, the phase rotation angle of ^{e−j4βs is 360 degrees.} When the range of the distance s to be changed is set from 0 to half wavelength at the measurement frequency, e ^{−j2βs becomes e−j2βs} = e− ^{j2 (2π / λ) (λ / 2)} = e− ^j2π at half wavelength. ^Therefore , e −j4βs is half wavelength (λ / 2) and e ^−j4βs = e ^{−j4 (2π / λ) (λ / 2)} = e ^−j4π for two rounds. When e ^−j2π = e ^−j4π = 1, max (S _{11, s} −S _{11, ave} ) is obtained, and from the above equation (6), max (S _{11, s} −S _{11, ave} ) is It is represented by the following formula (7). When e ^−jπ = -1 and e ^−j2π = 1, min (S _{11, s} −S _{11, ave} ) is obtained, and from the above equation (6), min (S _{11, s} −S _{11, ave} ) is represented by the following equation (8).
max (S _{11, s-} S _{11, ave} ) = 2S ₄₁ + S ₄₄ ... (7)
min (S _{11, s-} S _{11, ave} ) = -2S ₄₁ + S ₄₄ ... (8)

_{Subsequently, the arithmetic unit 31A calculates the parameter S 41} using the maximum value calculated according to the above formula (7) and the minimum value calculated according to the above formula (8) (step ST3c).
From the above equation (7) and the above equation (8), the parameter S ₄₁ is represented by the following equation (9).
_{After that, the arithmetic unit 31A substitutes the parameter S 41} calculated using the following equation (9) into the above equation (4) to calculate the axial ratio AR (step ST4c).
S ₄₁ = (max (S _{11, s-} S _{11, ave} ) -min (S _{11, s-} S _{11, ave} )) / 4 ... (9)

As described above, in the axial ratio measuring method according to the second embodiment, the output ports 13 and 14 of the circularly polarized light feeding circuit 1 are short-termized, and the output ports 13 and 14 and the short-circuited terminal positions are short-term terminated. The reflection characteristics of the circularly polarized light input port 11 when the distance s between the two is changed are measured, and the axial ratio of the circularly polarized light is calculated from the measured value of the measured reflection characteristics. Since the measured value of the reflection characteristic at the input port 11 is used for the axial ratio measurement without using the radio wave propagating in space, the influence of the surrounding environment on the axial ratio measurement can be reduced.

Further, in the axial ratio measuring method according to the second embodiment, it is not necessary to measure the reflection characteristics at the input ports 11 and 12 in the state where the output ports 13 and 14 are non-reflective terminated, and the output ports 13 and 14 are short-circuited. Only the measurement in the terminated state is required. Therefore, the measurement result of the axial ratio by the axial ratio measuring method according to the second embodiment is not affected by the measurement error of the reflection characteristic measured in the state where the output ports 13 and 14 are non-reflective terminated. The measurement accuracy of the axial ratio is improved as compared with.

Embodiment 3.
FIG. 9 is a block diagram showing the configuration of the circularly polarized wave feeding circuit 1 in which the output ports 13 and 14 are short-circuited and the axial ratio measuring device according to the third embodiment. The axial ratio measuring device shown in FIG. 9 is a device for measuring the axial ratio of the circularly polarized light of the circularly polarized light feeding circuit 1, and includes a reflection measuring device 30A and an arithmetic unit 31B. Hereinafter, the method of measuring the axial ratio of RHCP in the circularly polarized wave feeding circuit 1 will be described, but the measurement of the axial ratio of LHCP is also the same.

Similar to FIG. 3, a short-circuit plate 21 is connected to the output ports 13 and 14, and the distance s between the output ports 13 and 14 and the position of the short-circuit plate 21 can be changed. For example, when the output ports 13 and 14 are circular waveguides or square waveguides, a waveguide having the same cross-sectional shape as the output port is mounted between the output ports 13 and 14 and the short-circuit plate 21. Therefore, the distance s can be changed. The waveguide mounted between the output ports 13 and 14 and the short-circuit plate 21 may have various lengths depending on the range in which the distance s is changed.

The reflection measuring instrument 30A is, for example, a network analyzer, as in the second embodiment. When measuring the axial ratio of the RHCP, the reflection measuring instrument 30A is the input port 11 when the distance s between the output ports 13 and 14 and the short-circuit termination position is changed while the output ports 13 and 14 are short-circuited. The reflection characteristics of each are measured.
When measuring the axial ratio of the LHCP, the reflection measuring device 30A inputs when the distance s between the output ports 13 and 14 and the short-circuited termination position is changed while the output ports 13 and 14 are short-circuited. The reflection characteristics at the port 12 are measured respectively.

The arithmetic unit 31B is, for example, a computer, and calculates the axial ratio of circularly polarized light using the measured value of the reflection characteristic measured by the reflection measuring device 30A. _{For example, the arithmetic unit 31B has parameters S 11 and s} indicating the reflection characteristics at the input port 11 measured when the distance s between the output ports 13 and 14 and the short-circuit termination position is changed by the reflection measuring device 30A. _{The parameter S 41} is calculated by solving a simultaneous equation in which _{the value obtained by subtracting the average values S11} and ave of these measured values from the measured values is set as the known number and the parameter S _{41 corresponding to the cross polarization discrimination degree is set as the unknown number.} Then, the axial ratio of RHCP is calculated using the parameter S _41.

Next, the operation will be described.
_{The process of measuring the parameters S11 and s} by the reflection measuring device 30A is the same as the loop process of step ST1b shown in FIG. 7, and thus the description thereof will be omitted.
FIG. 10 is a flowchart showing the axial ratio calculation process in the axial ratio measuring method according to the third embodiment, and corresponds to the process of step ST2b shown in FIG. 7.
The arithmetic unit 31B uses the above equation (5) to change the distance s between the output ports 13 and 14 and the short-circuit end position, and the average value of the measured values of _{the plurality of parameters S 11 and s S 11, ave.} Is calculated (step ST1d).

Since the second and third terms of the right side of the equation (1) is 0, the average value _{S 11, ave} is approximated by the parameter _{S 11.} The parameters S _{11 and s} are represented by a complex number using the phase and amplitude measured by the reflection measuring device 30A, and the average is calculated as the complex number. It is possible to measure the relative phase when the distance s is changed. Average _{S 11, ave} is, since it is approximated by the parameter _{S 11,} the equation (6) is obtained on the values obtained by subtracting the average value _{S 11, ave} from the parameter _{S 11, s.}

Subsequently, the arithmetic unit 31B sets (S _{11, s} −S _{11, ave} ) on the left side and the propagation constant β and the distance s on the right side of _{the above equation (6) as known numbers, and sets the parameters S 41} and S ₄₄ as unknown numbers. The simultaneous equations are generated, and these simultaneous equations are solved _{to calculate the parameter S 41} (step ST2d).

Since the phase and amplitude representative of the parameter _{S 41, S 44} by reflectometry instrument 30A is measured, the parameters _{S 41, S 44,} it is necessary to calculate a complex number with phase and amplitude. Therefore, the simultaneous equations for obtaining the parameter S ₄₁ are required to be equal to or larger than the number of values of the distance s. These simultaneous equations can be solved using the method of least squares. By increasing the number of values of the distance s and increasing the number _{of simultaneous equations for obtaining the parameter S 41} , the measurement error of the axial ratio can be reduced.

_{After that, the arithmetic unit 31B calculates the axial ratio AR by substituting the parameter S 41} obtained by solving the simultaneous equations into the above equation (4) (step ST3d).

As described above, the axial ratio measuring method according to the third embodiment is a parameter indicating the reflection characteristic at the input port 11 measured when the distance s between the output ports 13 and 14 and the short-circuit end position is changed. from the measured values of S _{11, s,} the average value S _{11, ave} value obtained by subtracting the these measurements and the known number, by solving the simultaneous equations in which the parameter S ₄₁ which corresponds to the cross polarization discrimination with unknown parameters S ₄₁ is calculated, and the axial ratio of circular polarization is calculated using the parameter S _41. Since the measured value of the reflection characteristic at the input port 11 is used for the axial ratio measurement without using the radio wave propagating in space, the influence of the surrounding environment on the axial ratio measurement can be reduced.

Further, in the axial ratio measuring method according to the third embodiment, it is not necessary to measure the reflection characteristics at the input ports 11 and 12 in the state where the output ports 13 and 14 are non-reflective terminated, and the output ports 13 and 14 are short-circuited. Only the measurement in the terminated state is required. Therefore, the measurement result of the axial ratio by the axial ratio measuring method according to the third embodiment is not affected by the measurement error of the reflection characteristic measured in the state where the output ports 13 and 14 are non-reflective terminated. The measurement accuracy of the axial ratio is improved as compared with. Further, by increasing the number of values of the distance s and increasing the number _{of simultaneous equations for obtaining the parameter S 41} , the measurement error of the axial ratio is reduced.

Embodiment 4.
FIG. 11 is a block diagram showing the configuration of the circularly polarized wave feeding circuit 1 in which the output ports 13 and 14 are short-circuited and the axial ratio measuring device according to the fourth embodiment. The axial ratio measuring device shown in FIG. 11 is a device that measures the axial ratio of circularly polarized light fed by the circularly polarized light feeding circuit 1, and includes a reflection measuring device 30A and an arithmetic unit 31C. Hereinafter, a method of measuring the RHCP axial ratio in the circularly polarized wave feeding circuit 1 will be described, but the same applies to the measurement of the LHCP axial ratio.

Similar to FIG. 3, a short-circuit plate 21 is connected to the output ports 13 and 14, and the distance s between the output ports 13 and 14 and the position of the short-circuit plate 21 can be changed. For example, when the output ports 13 and 14 are circular waveguides or square waveguides, a waveguide having the same cross-sectional shape as the output port is mounted between the output ports 13 and 14 and the short-circuit plate 21. Therefore, the distance s can be changed. The waveguide mounted between the output ports 13 and 14 and the short-circuit plate 21 may have various lengths depending on the range in which the distance s is changed.

The reflection measuring instrument 30A is, for example, a network analyzer, as in the second and third embodiments. Since the axial ratio of the RHCP is measured, the reflection measuring instrument 30A is the input port 11 when the distance s between the output ports 13 and 14 and the short-circuit termination position is changed while the output ports 13 and 14 are short-circuited. The reflection characteristics of each are measured.
When measuring the axial ratio of the LHCP, the reflection measuring device 30A inputs when the distance s between the output ports 13 and 14 and the short-circuited termination position is changed while the output ports 13 and 14 are short-circuited. The reflection characteristics at the port 12 are measured respectively.

The arithmetic unit 31C is, for example, a computer, and calculates the axial ratio of circularly polarized light using the measured value of the reflection characteristic measured by the reflection measuring device 30A. For example, the arithmetic unit 31C is a measurement value of the _{parameters S 11 and s} indicating the reflection characteristics at the input port 11 measured when the distance s between the output ports 13 and 14 and the short-circuit end position is changed by the reflection measuring device 30A. _{Is a known number, the parameter S 41} is calculated by solving a simultaneous equation in which _{the parameter S 41} corresponding to the cross polarization discrimination degree is an unknown number, and the axial ratio of the RHCP is calculated using _{the parameter S 41.}

Next, the operation will be described.
_{The process of measuring the parameters S11 and s} by the reflection measuring device 30A is the same as the loop process of step ST1b shown in FIG. 7, and thus the description thereof will be omitted.
FIG. 12 is a flowchart showing the axial ratio calculation process in the axial ratio measuring method according to the fourth embodiment, and corresponds to the process of step ST2b shown in FIG. 7.
The arithmetic unit 31C uses a simultaneous equation with _{the left side S 11, s} of the above equation (1), the propagation constant β on the right side, and the distance s as known numbers, and the parameters S ₁₁ , S ₄₁ , and S _{44 as unknown numbers, and sets the distance s.} The number of values of is generated, and these simultaneous equations are solved _{to calculate the parameter S 41} (step ST1e).

When the phase and amplitude is measured representing the parameter _{S 11, S 41, S 44} by reflectometry instrument 30A, the parameter _{S 11, S 41, S 44,} it is necessary to calculate a complex number with phase and amplitude. In this case, the number of values of the distance s is 6 or more, that is, 6 or more simultaneous equations for obtaining the _{parameter S 41 are required.}

Further, when the reflection measuring device 30A measures only the amplitude representing _{the parameter S 11} , the number of simultaneous equations for obtaining the _{parameter S 41 may be five or more.} That is, the number of values of the distance s may be 5 or more. These simultaneous equations can be solved using the method of least squares.
By increasing the number of values of the distance s and increasing the number _{of simultaneous equations for obtaining the parameter S 41} , the measurement error of the axial ratio can be reduced.

_{After that, the arithmetic unit 31C calculates the axial ratio AR by substituting the parameter S 41} obtained by solving the simultaneous equations into the above equation (4) (step ST2e).

_{As described above, in the axial ratio measuring method according to the fourth embodiment, the parameter S 11} indicating the reflection characteristic at the input port 11 measured when the distance s between the output ports 13 and 14 and the short-circuit end position is changed. _{The parameter S 41} is calculated by solving a simultaneous equation in which _{the measured values of, and s are known numbers and the parameter S 41} which is the cross polarization discrimination degree is an unknown number, and the axial ratio of circularly polarized light is calculated using the parameter S _41. calculate. Since the measured value of the reflection characteristic at the input port 11 is used for the axial ratio measurement without using the radio wave propagating in space, the influence of the surrounding environment on the axial ratio measurement can be reduced.

Further, in the axial ratio measuring method according to the fourth embodiment, it is not necessary to measure the reflection characteristics at the input ports 11 and 12 in the state where the output ports 13 and 14 are non-reflective terminated, and the output ports 13 and 14 are short-circuited. Only the measurement in the terminated state is required. Therefore, the measurement result of the axial ratio by the axial ratio measuring method according to the fourth embodiment is not affected by the measurement error of the reflection characteristic measured in the state where the output ports 13 and 14 are non-reflective terminated. The measurement accuracy of the axial ratio is improved as compared with. Further, by increasing the number of values of the distance s and increasing the number _{of simultaneous equations for obtaining the parameter S 41} , the measurement error of the axial ratio is reduced.

It should be noted that the present invention is not limited to the above-described embodiment, and within the scope of the present invention, any combination of the embodiments or any component of the embodiment may be modified or the embodiment. Any component can be omitted in each of the above.

Since the axial ratio measuring method according to the present invention can measure the axial ratio that is not easily affected by the surrounding environment without using radio waves propagating in space, the axial ratio of various types of circularly polarized antennas can be measured. It can be used for measurement.

1 Circularly polarized power feeding circuit, 11,12 input port, 13,14 output port, 20 non-reflective terminator, 21 short circuit plate, 30, 30A reflection measuring device, 31, 31A, 31B, 31C arithmetic unit.

Claims (8)

With the circularly polarized output port of the circularly polarized power feeding circuit terminated without reflection, the step of measuring the reflection characteristics at the circularly polarized light input port of the circularly polarized power feeding circuit, and
With the output port short-circuited, the step of measuring the reflection characteristics at the input port when the distance between the output port and the short-circuited termination position is changed, and
A step of calculating the axial ratio of circularly polarized light using the measured values of the reflection characteristics measured in each of the state where the output port is non-reflectively terminated and the state where the output port is short-circuited.
Axial ratio measuring method characterized by being provided with. From the maximum value of the reflection characteristic measured at the input port measured when the distance between the output port and the short-circuit termination position is changed, the output port is measured in a non-reflection termination state. The measured value of the reflection characteristic at the input port and the measured value of the reflection characteristic at the input port where the circularly polarized light that is opposite to the circularly polarized light input to the input port is input, and the value is subtracted. The axial ratio measuring method according to claim 1, wherein the cross-polarized light discrimination degree, which is a value obtained by dividing the cross-polarized light, is calculated, and the axial ratio of circularly polarized light is calculated using the cross-polarized light discrimination degree. .. Measure the reflection characteristics at the circularly polarized input port when the distance between the output port and the short-circuited termination position is changed while the circularly polarized output port in the circularly polarized power supply circuit is short-circuited. Steps to do and
A step of calculating the axial ratio of circularly polarized light using the measured value of the reflection characteristic measured with the output port short-circuited.
Axial ratio measuring method characterized by being provided with. The average value of these measured values is subtracted from the measured values of the reflection characteristics at the input port measured when the distance between the output port and the short-circuit termination position is changed, and the maximum of the subtracted values is obtained. A claim characterized in that the cross-polarization discrimination degree, which is a value obtained by dividing the difference between the value and the minimum value by 4, is calculated, and the axial ratio of circularly polarized light is calculated using the cross-polarization discrimination degree. 3. The axial ratio measuring method according to 3. The known number includes the value obtained by subtracting the average value of these measured values from the measured value of the reflection characteristic at the input port measured when the distance between the output port and the short-circuit termination position is changed, and intersects. A claim characterized in that the cross polarization discrimination degree is calculated by solving a simultaneous equation including the polarization discrimination degree in an unknown number, and the axial ratio of circularly polarized light is calculated using the cross polarization discrimination degree. 3. The axial ratio measuring method according to 3. By solving a simultaneous equation that includes the measured value of the reflection characteristic at the input port measured when the distance between the output port and the short-circuit termination position is changed in the known number and the cross-polarization discrimination degree in the unknown number. The axial ratio measuring method according to claim 3, wherein the cross-polarized light discrimination degree is calculated, and the axial ratio of circularly polarized light is calculated using the cross-polarized light discrimination degree. With the circularly polarized output port of the circularly polarized power feeding circuit terminated non-reflectively, the reflection characteristic of the circularly polarized input port of the circularly polarized power feeding circuit was measured, and the output port was short-term terminated. In the state, a reflection measuring device that measures the reflection characteristics at the input port when the distance between the output port and the short-circuit termination position is changed, and
An arithmetic device that calculates the axial ratio of circularly polarized light using the measured values of reflection characteristics measured by the reflection measuring instrument in the state where the output port is non-reflectively terminated and when the output port is short-circuited. When,
Axial ratio measuring device characterized by being equipped with. Measured value of reflection characteristics at the circularly polarized input port when the distance between the output port and the short-circuited termination position is changed while the circularly polarized output port in the circularly polarized power supply circuit is short-circuited. With a reflection measuring device that measures each
An arithmetic unit that calculates the axial ratio of circularly polarized light using the measured value of the reflection characteristic measured with the output port short-circuited by the reflection measuring device.
Axial ratio measuring device characterized by being equipped with.

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