Radio wave change measurement device and transmission attenuation measurement system

Abstract

To provide a radio wave change measurement device and transmission attenuation measurement system, which enable measurement of the amount of radio wave attenuation due to an observation object (such as water vapor, moisture, fog, and rain) particularly in a frequency range of 70 to 370 GHz.SOLUTION: The present invention provides a radio wave change measurement device configured to transmit a plane radio wave into a space, insert an observation object for receiving the plane radio wave into the space, and measure a change in the radio wave transmitted through the observation object, where the radio wave change measurement device determines a physical constant of the observation object by matching a radio wave change curve based on change in the radio wave resulting from change in frequency of the plane radio wave and a physical constant change curve based on change in the physical constant of the observation object.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a radio wave change measuring device and a transmission attenuation measuring system. [Background technology]

[0002] If it were possible to know in advance (for example, about an hour before) that rain would fall, this could be useful for changing flight schedules, outdoor events, or, for example, changing the preparation of lunch boxes at outdoor events.

[0003] It is also well known that if we can accurately predict the recent sudden downpours, we can minimize the damage caused by the disaster, and the benefits of this are enormous. For this prediction, it is important to know the amount of moisture in the atmosphere.

[0004] For example, Non-Patent Document 1 reports a technique for dealing with radio wave attenuation due to fog and rain that affects communication. [Prior art documents] [Patent documents]

[0005] [Non-Patent Document 1] Deputy Chief of Staff, Research and Development in United States Air Force Project Rand, Attenuation of Electromagnetic Radiation by Haze, Fog, Clouds, and Rain R-1694-PR April 1975 Summary of the Invention [Problem to be solved by the invention]

[0006] However, Non-Patent Document 1 does not report any technology related to the attenuation of millimeter waves.

[0007] The present invention has been made in view of the above circumstances, and its main object is to provide a radio wave change measuring device and transmission attenuation measuring system that can measure the amount of radio wave attenuation of an object to be observed (e.g., water vapor, humidity, fog, rain, etc.), particularly in the frequency range of 70 GHz to 370 GHz. [Means for solving the problem]

[0008] As a result of intensive research to achieve the above-mentioned objective, the inventors have succeeded in measuring the amount of radio wave attenuation of an object to be observed (e.g., water vapor, humidity, fog, rain, etc.), particularly at frequencies from 70 GHz to 370 GHz, and have thus completed the present invention.

[0009] That is, in a first aspect, the present invention provides: A radio wave change measuring device that transmits (plane wave radio waves or radio waves that are plane waves) into space, inserts an observation object that receives the plane wave radio waves into the space, and measures changes in the radio waves that have passed through the observation object, The present invention provides a radio wave change measuring device that determines the physical constants of an object to be observed by matching a radio wave change curve based on changes in radio waves caused by changing the frequency of the plane wave radio waves with a physical constant change curve based on changes in the physical constants of the object to be observed.

[0010] The radio wave change measuring device according to the first aspect of the present invention may measure the transmission attenuation of radio waves that have passed through the object to be observed.

[0011] In the radio wave change measurement device according to the first aspect of the present invention, The object to be observed may be water vapor, humidity, fog, or rain.

[0012] In the radio wave change measurement device according to the first aspect of the present invention, The frequency of the plane wave may be in the range of 70 GHz to 370 GHz.

[0013] In addition, in the present invention, as a second aspect, a transmitting antenna for transmitting radio waves to an observation target; a receiving antenna for receiving radio waves transmitted through the target; a first dielectric lens disposed on the radio wave transmitting side of the transmitting antenna; a second dielectric lens disposed on the radio wave receiving side of the receiving antenna; a network analyzer that generates radio waves and outputs them to the transmitting antenna and inputs the transmitted radio waves received by the receiving antenna, The present invention provides a transmission attenuation measurement system in which the network analyzer measures the frequency characteristics of the passing power of a high-frequency circuit network and calculates the transmission attenuation of the object to be observed.

[0014] In the transmission attenuation measurement system according to the second aspect of the present invention, The network analyzer may measure the passing power (|S21|) and calculate the transmission attenuation of the object to be observed.

[0015] In the transmission attenuation measurement system according to the second aspect of the present invention, The network analyzer may measure a phase difference (Δθ) in a vacuum and calculate the relative dielectric constant (εr′) of the object to be observed.

[0016] In the transmission attenuation measurement system according to the second aspect of the present invention, The network analyzer may measure passing power (|S21|) and calculate tan δ of the object to be observed.

[0017] In the transmission attenuation measurement system according to the second aspect of the present invention, The object to be observed may be water vapor, humidity, fog, or rain.

[0018] In the transmission attenuation measurement system according to the second aspect of the present invention, The frequency of the radio waves may be in the range of 70 GHz to 370 GHz. [Effects of the Invention]

[0019] According to the present invention, the attenuation of radio waves from an object to be observed (e.g., water vapor, humidity, fog, rain, etc.) can be measured, particularly at frequencies from 70 GHz to 370 GHz. Note that the effects described here are not necessarily limited to those described herein, and may be any of the effects described herein. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a transmission attenuation measurement system to which the present invention is applied. [Figure 2] FIG. 2 is a diagram showing an example of the configuration of a transmission attenuation measuring system to which the present invention is applied. [Figure 3] FIG. 3 is a diagram for explaining an example of processing of measurement data of |S21| and the vacuum phase difference Δθ. [Figure 4] FIG. 4 is a diagram showing the relationship between |S21| [dB] and frequency [GHz]. [Figure 5] FIG. 5 is a diagram showing the relationship between Δθ [dB] and frequency [GHz]. DETAILED DESCRIPTION OF THE INVENTION

[0021] A preferred embodiment for carrying out the present invention will be described below. The embodiment described below shows an example of a typical embodiment of the present invention, and the scope of the present invention should not be construed as being narrow.

[0022] Unless otherwise specified, in the drawings, "upper" means the upper direction or upper side in the drawing, "lower" means the lower direction or lower side in the drawing, "left" means the left direction or left side in the drawing, and "right" means the right direction or right side in the drawing. Furthermore, in the drawings, the same or equivalent elements or members are given the same reference numerals, and redundant explanations will be omitted.

[0023] The explanation will be given in the following order. 1. Overview of the Invention 2. First embodiment (measurement principle: measurement and calculation of transmission attenuation, relative dielectric constant, and tan δ) 3. Second Embodiment (Measurement Results: Transmission Attenuation, Dielectric Constant, and Tan δ)

[0024] <1. Overview of the present invention> First, an outline of the present invention will be described.

[0025] The radio wave change measuring device according to the present invention is a compact and highly sensitive measuring device. The radio wave change measuring device according to the present invention transmits a plane wave radio wave into space, inserts an object of observation into the space to receive the plane wave radio wave, and measures changes in the radio wave that have passed through the object of observation. Furthermore, the radio wave change measuring device according to the present invention is a device that determines the physical constants of an object of observation by matching a radio wave change curve based on changes in the radio wave caused by changing the frequency of the plane wave radio wave with a physical constant change curve based on changes in the physical constants of the object of observation.

[0026] The transmission attenuation measurement system according to the present invention is a compact and highly sensitive measurement system. The transmission attenuation measurement system according to the present invention includes a transmitting antenna that transmits radio waves to an object to be observed, a receiving antenna that receives the transmitted radio waves that have transmitted through the object to be observed, a first dielectric lens arranged on the radio wave transmitting side of the transmitting antenna, a second dielectric lens arranged on the radio wave receiving side of the receiving antenna, and a network analyzer that generates radio waves, outputs them to the transmitting antenna, and inputs the transmitted radio waves received by the receiving antenna. Furthermore, the transmission attenuation measurement system according to the present invention is a system in which the network analyzer measures the frequency characteristics of the passing power of a high-frequency circuit network and calculates the transmission attenuation of the object to be observed.

[0027] Before using radar to determine cloud conditions, if the amount of millimeter wave attenuation in the atmosphere through which the radar waves pass (transmit) is known, the amount of moisture in the atmosphere can be estimated. This makes it possible to predict rainfall in advance (for example, about one hour in advance). Then, based on the amount of millimeter wave reflection from clouds, it is possible to more accurately predict rainfall in advance (for example, about 10 minutes in advance).

[0028] The radio wave change measuring device according to the present invention and the transmission attenuation measuring system according to the present invention can measure the transmission attenuation of radio waves through an object to be observed (for example, water vapor, humidity, fog, rain, etc.). In particular, the radio wave change measuring device, which is a compact and highly sensitive measuring device according to the present invention, and the transmission attenuation measuring system, which is a compact and highly sensitive measuring system according to the present invention, can be used to accurately measure the transmission attenuation of radio waves through an object to be observed, such as fog, where the water droplets have a diameter of 20 μm to 30 μm. However, since the wavelength of a frequency of 170 GHz is 180 μm, for example, the diameter of the water droplets must be taken into consideration when determining the measurement accuracy.

[0029] Furthermore, by using the radio wave change measurement device and transmission attenuation measurement system according to the present invention, the relative permittivity (εr') and tan δ of water droplets can be calculated. This invention is expected to improve the accuracy of weather radar predictions based on laboratory data.

[0030] Hereinafter, embodiments (first and second embodiments) according to the present invention will be specifically and in detail described.

[0031] <2. First Embodiment (Measurement Principle: Measurement and Calculation of Transmission Attenuation, Relative Dielectric Constant, and Tan δ)> Because water vapor, humidity, fog, rain, etc. cause large fluctuations in transmission attenuation even over a short period of time, the measurement method involves changing the frequency and determining the average value of the fluctuations in transmission attenuation as the transmission attenuation value. This measurement method is sometimes called the "frequency change method."

[0032] The frequency change method can be carried out using the radio wave change measuring device or transmission attenuation measuring system according to the present invention.

[0033] The description will be made with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of a transmission attenuation measurement system to which the present invention is applied, and more specifically, a diagram showing the configuration of a transmission attenuation measurement system 100.

[0034] The transmission attenuation measurement system 100 comprises a transmitting antenna 1 that transmits radio waves to an observation target 3, a receiving antenna 5 that receives the transmitted radio waves that have passed through the observation target 3, a first dielectric lens 2 arranged on the radio wave transmitting side of the transmitting antenna 1, a second dielectric lens 4 arranged on the radio wave receiving side of the receiving antenna 5, and a network analyzer 6 that generates radio waves and outputs them to the transmitting antenna 1 and inputs the transmitted radio waves received by the receiving antenna 5.

[0035] The network analyzer 6 measures the frequency characteristics of the passing power (|S21|) of the high-frequency circuit network, and calculates the transmission attenuation of the observation target 3.

[0036] 1, the transmitting antenna 1 and the network analyzer 6 are connected via a cable 9, and the receiving antenna 5 and the network analyzer 6 are connected via a cable 10. The network analyzer 6 and the personal computer (PC) 7 are connected via a GPIB cable, and the personal computer (PC) 7 and the printer 8 are connected via a cable 12.

[0037] The transmission attenuation measuring system 100 has at least the following three features for millimeter waves. 1. Measurements can be made using plane wave radio waves, making it easy to set up the object of observation (sample). 2. It is possible to measure thick objects (samples). 3. By fitting the measured data curve to the theoretical curve over a wide range of frequencies, the measured data line can be clarified even when the data has a lot of time fluctuation or noise, thereby improving sensitivity.

[0038] Next, the methods for calculating the transmission attenuation α, the relative dielectric constant εr′, and tan δ will be described. If α is the transmission attenuation and L is the thickness of the fog, etc. [m], the transmission attenuation can be expressed as follows: α = |S21| / L [dB / m] (1)

[0039] If the phase difference that occurs when there is mist or the like with a thickness L in a vacuum is Δθ, Δθ can be expressed as follows: Δθ=(360f / c)×(√(εr´)-1)×L[deg]···(1-1) In the above formula, c is the speed of light, and f is the frequency [GHz].

[0040] Therefore, the relative dielectric constant εr' is expressed as follows: εr´=(Δθ / (360f×L)+1) 2 ····(2)

[0041] On the other hand, since α=91f√(εr´)×tanδ[dB / m], Tan δ is expressed as follows: tanδ=α / (91f×√(εr´))····(3)

[0042] <3. Second Embodiment (Measurement Results: Measurement Results of Transmission Attenuation, Relative Dielectric Constant, and Tan δ)> The measurement results of transmission attenuation, relative dielectric constant and tan δ will be explained.

[0043] In a transmission attenuation measurement system 200 (sometimes referred to as a frequency change method system) shown in Fig. 2, mist 3 was sprayed by a sprayer 13 into the 1.0 m space between two dielectric lenses 2 and 4, and the phase difference Δθ between |S21| in the mist 3 and the vacuum was measured. The thickness of the mist to be observed (sample) was set to 0.4 m.

[0044] The average particle size and amount of mist ejected from the mist 3 are as follows: Average fog particle size: 20-30 μm (measured by laser Doppler method) ·Water (fog) spray amount: 5liter / hr.

[0045] Next, an example of measurement data processing is shown in Fig. 3. Fig. 3 is a diagram for explaining an example of processing measurement data of |S21| dB and vacuum phase difference Δθ deg, and more specifically, in processing example 370, the left side of the vertical axis of the graph represents |S21| dB, the right side of the vertical axis represents Δθ deg, and the horizontal axis represents frequency (GHz).

[0046] A diagram showing the relative permittivity (ε′) and dielectric loss (ε′′) is shown in the lower left of the processing example 300. The relative permittivity (ε′) on the vertical axis and the dielectric loss (ε′′) on the horizontal axis can be moved using a cursor.

[0047] 3, theoretical curve 301 of |S21| is fitted to measured curve 302 of |S21|, and theoretical curve 303 of Δθ is fitted to measured curve 304 of Δθ. This allows the transmission attenuation α to be calculated from |S21| and the fog thickness l (m) using equation (1) above, and then the relative dielectric constant εr' is calculated from Δθ and the fog thickness l (m) using equation (2) above. Furthermore, using the calculated transmission attenuation α and relative dielectric constant εr', tan δ is found using equation (3) above.

[0048] In the physical constant change curve based on the change in the physical constant of the object of observation, the change in the physical constant of the object of observation can be determined by arbitrarily changing |S21| and Δθ of the object of observation based on the above-mentioned theoretical formula (1), theoretical formula (1-1), theoretical formula (2), and theoretical formula (3), thereby creating the theoretical formula curve 301 of |S21| and the theoretical formula curve 303 of Δθ shown in FIG. 3.

[0049] Fig. 4 is a diagram showing the relationship between |S21| [dB] and frequency [GHz]. More specifically, graph 400 shown in Fig. 4 is an enlarged view of measurement curve 302 of |S21| shown in the graph in processing example 300, where reference numeral 401 indicates the measurement result of |S21| [dB] at frequencies from 70 GHz to 90 GHz, reference numeral 402 indicates the measurement result of |S21| [dB] at frequencies from 90 GHz to 110 GHz, and reference numeral 403 indicates the measurement result of |S21| [dB] at frequencies from 110 GHz to 170 GHz.

[0050] Fig. 5 is a diagram showing the relationship between Δθ [dB] and frequency [GHz]. More specifically, graph 500 shown in Fig. 5 is an enlarged view of measurement curve 304 of Δθ shown in the graph in processing example 300, where reference numeral 501 indicates the measurement result of Δθ [deg] at frequencies of 70 GHz to 90 GHz, reference numeral 502 indicates the measurement result of Δθ [deg] at frequencies of 90 GHz to 110 GHz, and reference numeral 503 indicates the measurement result of Δθ [deg] at frequencies of 110 GHz to 170 GHz.

[0051] To summarize the above, the calculation results (measurement results) of the transmission attenuation [dB / m], relative dielectric constant (εr') and tan δ at frequencies of 70 GHz to 90 GHz, 90 GHz to 110 GHz and 110 GHz to 170 GHz are shown in Table 1 below.

[0052] JPEG2025119551000002.jpg74150

[0053] Using the radio wave change measurement device and transmission attenuation measurement system of the present invention, it was confirmed that the amount of radio wave transmission attenuation due to the amount of moisture in the atmosphere varies depending on the frequency. If we assume that the diameter of cloud raindrops is 2 mm or more and that their reflection is not significantly different between 70 GHz and 150 GHz, the difference in the attenuation of the radar's round trip depending on frequency will represent the amount of moisture in the atmosphere. This makes it possible to predict, for example, that if the moisture content is high, rain will occur after about an hour. This type of prediction measurement experiment can now be conducted indoors.

[0054] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0055] The present invention can have the following configurations. [1] A radio wave change measuring device that transmits a plane wave radio wave into a space, inserts an observation object that receives the plane wave radio wave into the space, and measures changes in the radio wave that has passed through the observation object, A radio wave change measuring device that determines the physical constants of an object to be observed by matching a radio wave change curve based on changes in radio waves caused by changing the frequency of the plane wave radio waves with a physical constant change curve based on changes in the physical constants of the object to be observed.

[0056] [2] The radio wave change measuring device according to [1] measures the transmission attenuation of radio waves that have passed through the object to be observed.

[0057] [3] The radio wave change measuring device according to [1] or [2], wherein the object to be observed is water vapor, humidity, fog, or rain.

[0058] [4] The radio wave change measuring device according to any one of [1] to [3], wherein the frequency of the plane wave radio wave is in the range of 70 GHz to 370 GHz.

[0059] [5] a transmitting antenna for transmitting radio waves to an observation target; a receiving antenna for receiving radio waves transmitted through the target; a first dielectric lens disposed on the radio wave transmitting side of the transmitting antenna; a second dielectric lens disposed on the radio wave receiving side of the receiving antenna; a network analyzer that generates radio waves and outputs them to the transmitting antenna and inputs the transmitted radio waves received by the receiving antenna, The transmission attenuation measurement system, wherein the network analyzer measures the frequency characteristics of the passing power of a high-frequency circuit network and calculates the transmission attenuation of the object to be observed.

[0060] [6] The transmission attenuation measurement system according to [5], wherein the network analyzer measures the passing power (|S21|) and calculates the transmission attenuation of the object to be observed.

[0061] [7] The transmission attenuation measurement system according to [5] or [6], wherein the network analyzer measures a phase difference (Δθ) in a vacuum and calculates a relative dielectric constant (εr') of the object to be observed.

[0062] [8] The transmission attenuation measurement system according to any one of [5] to [7], wherein the network analyzer measures a passing power (|S21|) and calculates tan δ of the object to be observed.

[0063] [9] The radio wave change measuring device according to any one of [5] to [8], wherein the object to be observed is water vapor, humidity, fog, or rain.

[0064]

[10] The radio wave change measuring device according to any one of [5] to [9], wherein the frequency of the radio wave is in the range of 70 GHz to 370 GHz. [Explanation of symbols]

[0065] 1. Transmitting antenna, 2. First dielectric lens; 3. Observation object (sample), 4. Second derivative lens, 5. Receiving antenna, 6. Network analyzer, 7. Personal computer (PC), 8. Printer, 9···First cable, 10...Second cable, 11. GPIB cable, 12···Third cable, 13...spray machine, 100... Transmission attenuation measurement system, 200···Transmission attenuation measurement system.

Claims

1. A radio wave change measuring device that transmits a plane wave radio wave into a space, inserts an observation object that receives the plane wave radio wave into the space, and measures changes in the radio wave that has passed through the observation object, A radio wave change measuring device that determines the physical constants of an object to be observed by matching a radio wave change curve based on changes in radio waves caused by changing the frequency of the plane wave radio waves with a physical constant change curve based on changes in the physical constants of the object to be observed.

2. 2. The radio wave change measuring device according to claim 1, wherein the transmission attenuation of the radio wave transmitted through the object to be observed is measured.

3. 2. The radio wave variation measuring device according to claim 1, wherein the observation target is water vapor, humidity, fog, or rain.

4. 2. The radio wave change measuring device according to claim 1, wherein the frequency of the plane wave radio wave is in the range of 70 GHz to 370 GHz.

5. a transmitting antenna for transmitting radio waves to an observation target; a receiving antenna for receiving radio waves transmitted through the target; a first dielectric lens disposed on the radio wave transmitting side of the transmitting antenna; a second dielectric lens disposed on the radio wave receiving side of the receiving antenna; a network analyzer that generates radio waves and outputs them to the transmitting antenna and inputs the transmitted radio waves received by the receiving antenna, The transmission attenuation measurement system, wherein the network analyzer measures the frequency characteristics of the passing power of a high-frequency circuit network and calculates the transmission attenuation of the object to be observed.

6. 6. The transmission attenuation measurement system according to claim 5, wherein the network analyzer measures the passing power (|S21|) and calculates the transmission attenuation of the object to be observed.

7. 6. The transmission attenuation measurement system according to claim 5, wherein the network analyzer measures a phase difference (Δθ) in a vacuum and calculates the relative permittivity (εr') of the object to be observed.

8. 6. The transmission attenuation measurement system according to claim 5, wherein the network analyzer measures a passing power (|S21|) and calculates tan δ of the object to be observed.

9. 6. The radio wave variation measuring device according to claim 5, wherein the observation target is water vapor, moisture, fog, or rain.

10. 6. The radio wave change measuring device according to claim 5, wherein the frequency of the radio wave is in the range of 70 GHz to 370 GHz.

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