阅读说明：本技术 一种用于测量橡胶乳胶等溶液浓度的微波谐振结构和系统 (Microwave resonance structure and system for measuring concentration of solutions such as rubber latex ) 是由 谢晓鹏 崔耀中 郭建涛 郭晋川 赵阳 于 2021-07-01 设计创作，主要内容包括：本发明公开了一种用于测量橡胶乳胶等溶液浓度的微波谐振结构和系统,包括圆柱型腔体,所述圆柱型腔体顶部为开口设置,所述圆柱型腔体底部开设有圆孔,所述圆孔内腔设有同轴探针,所述同轴探针外侧边缘套设有绝缘介质,将橡胶乳胶充满圆柱型腔体的整个空间,相比于谐振腔微扰法测量被测液体,被测液体对谐振腔谐振频率的影响大,因此可以更加灵敏更加准确的测量被测液体的介电常数变化；通过圆柱型腔体顶面的开口设置,方便倒入和倒出被测量液体,测量过程方便快捷；通过使用金属探针与金属圆柱体形成的同轴结构对谐振腔体进行馈电,可采用SMA接头、N型接头、BNC结构等常用同轴结构进行馈电,实现方便、连接方便、成本低。(The invention discloses a microwave resonance structure and a microwave resonance system for measuring the concentration of solutions such as rubber latex and the like, and the microwave resonance structure and the microwave resonance system comprise a cylindrical cavity, wherein the top of the cylindrical cavity is provided with an opening, the bottom of the cylindrical cavity is provided with a round hole, the inner cavity of the round hole is provided with a coaxial probe, the outer edge of the coaxial probe is sleeved with an insulating medium, the rubber latex is filled in the whole space of the cylindrical cavity, and compared with a resonant cavity perturbation method for measuring the measured liquid, the influence of the measured liquid on the resonance frequency of a resonant cavity is large, so that the dielectric constant change of the measured liquid can be measured more sensitively and more accurately; the opening on the top surface of the cylindrical cavity is arranged, so that the measured liquid is convenient to pour and pour, and the measuring process is convenient and quick; the coaxial structure formed by the metal probe and the metal cylinder is used for feeding the resonant cavity, common coaxial structures such as an SMA connector, an N-type connector and a BNC structure can be used for feeding, and the coaxial structure is convenient to realize and connect and low in cost.)

1. A microwave resonance structure and system for measuring solution concentration such as rubber latex, including cylinder type cavity (3), its characterized in that: the utility model discloses a coaxial probe, including cylinder type cavity (3), round hole, coaxial probe (1), insulating medium (2), the round hole is seted up to cylinder type cavity (3) top for the opening setting, and it is half open setting, the round hole has been seted up to cylinder type cavity (3) bottom, the round hole inner chamber is equipped with coaxial probe (1), coaxial probe (1) outside edge cover is equipped with insulating medium (2), the laminating inside insulating medium (2) outside and the round hole, the bottom of cylinder type cavity (3) is equipped with coaxial signal feed-in structure (4).

2. The microwave resonance structure and system for measuring the concentration of a solution such as a rubber latex according to claim 1, wherein: the round holes are matched with the insulating medium (2).

3. The microwave resonance structure and system for measuring the concentration of a solution such as a rubber latex according to claim 1, wherein: the coaxial signal feed-in structure (4) is composed of a coaxial probe (1) and a cylindrical cavity (3).

4. The microwave resonance structure and system for measuring the concentration of a solution such as a rubber latex according to claim 1, wherein: the coaxial probe (1) and the top end of the insulating medium (2) extend to the inner cavity of the cylindrical cavity (3) together.

5. The microwave resonance structure and system for measuring the concentration of a solution such as a rubber latex according to claim 1, wherein: the insulating medium (2) is arranged in a cylindrical mode, and the insulating medium (2) is matched with the coaxial probe (1).

6. The microwave resonance structure and system for measuring the concentration of a solution such as a rubber latex according to claim 1, wherein: the cross section of the cylindrical cavity (3) is not limited to be cylindrical, and can be in a rectangular, spherical, trapezoidal and other structures.

7. The microwave resonance structure and system for measuring the concentration of a solution such as a rubber latex according to claim 1, wherein: the position of the round hole on the cylindrical cavity (3) is not limited to the central position of the cylindrical cavity (3).

8. The microwave resonance system for measuring the concentration of a solution such as a rubber latex according to claim 1, comprising the steps of:

s1: pouring rubber latex with different concentrations into the cylindrical cavity 3;

s2: then measuring an echo signal of the resonant cavity through the sweep frequency source module 6;

s3: echo signals of the resonant cavity are reflected back to a C2 port of the directional coupler 7 through a coaxial feed end and are coupled to a detection amplifying circuit through a C3 port;

s4: obtaining a fitting curve of the corresponding relation between the resonant frequency and the rubber latex concentration through the directional coupler module 7 and the analog amplification module 8;

s5: then, inquiring a fitting curve, and quickly measuring the concentration of the rubber latex;

s6: the existing scientific principle shows that the principle formula of the measurement is to measure the concentration of the rubber latex by the measurement principle that the dielectric constants of different media are different and the resonant frequencies are different.

Technical Field

The invention relates to the technical field of microwave resonance, in particular to a microwave resonance structure and a microwave resonance system for measuring the concentration of solutions such as rubber latex.

Background

The measurement of the concentration of the liquid mixture has wide requirements in the fields of agricultural production, chemical industry, medicine, life and the like. Methods for measuring concentration are also available, such as drying, evaporative curing measurements, density methods, viscometry, conductivity methods, optics, microwave transmittance methods, optical refractive index methods, and the like. Each mode has own advantages and disadvantages, and has the disadvantages of long measuring time, complex measurement, high measuring cost, limited application range and the like.

The principle of measuring the dielectric constant of liquid by using a microwave resonance method is also applied in scientific measuring instruments for a long time, and the dielectric constant of the liquid is related to the concentration (mass or volume percentage) of a substance, so that the method for measuring the concentration of the liquid by using the microwave has various modes; meanwhile, a small part of solution to be measured is placed in a closed container and then placed in a cavity to meet the requirements of the perturbation method, and the concentration of the substance is measured through the change of the resonant frequency.

Disclosure of Invention

The invention solves the technical problems of inconvenience in solution entering, low sensitivity and accuracy in measurement, single joint use and the like in the prior art, and provides a microwave resonance structure and a microwave resonance system for measuring the concentration of solutions such as rubber latex and the like. The microwave resonance structure and the system for measuring the concentration of the solution such as the rubber latex have the characteristics of convenience for solution entering, more sensitive and accurate measurement and capability of adopting common coaxial structures such as an SMA connector, an N-type connector and a BNC structure for feeding.

In order to achieve the purpose, the invention provides the following technical scheme: the utility model provides a microwave resonance structure and system for measuring solution concentration such as rubber latex, includes cylinder type cavity, cylinder type cavity top is the opening setting, and it is half open setting, the round hole has been seted up to cylinder type cavity bottom, the round hole inner chamber is equipped with coaxial probe, coaxial probe outside edge cover is equipped with insulating medium, the insulating medium outside is laminated with the round hole is inside, the bottom of cylinder type cavity is equipped with coaxial signal feed-in structure.

Preferably, the round hole is matched with the insulating medium.

Preferably, the coaxial signal feed-in structure is composed of a coaxial probe and a cylindrical cavity.

Preferably, the coaxial probe and the top end of the insulating medium extend to the inner cavity of the cylindrical cavity body together.

Preferably, the insulating medium is arranged in a cylindrical shape, and the insulating medium is matched with the coaxial probe.

Preferably, the cross section of the cylindrical cavity is not limited to a cylinder, and can be in a rectangular, spherical, trapezoidal or other structure.

Preferably, the position of the circular hole on the cylindrical cavity is not limited to the central position of the cylindrical cavity.

A microwave resonance system for measuring the concentration of a solution such as rubber latex comprises the following steps:

s1: pouring rubber latex with different concentrations into the cylindrical cavity;

s2: then measuring an echo signal of the resonant cavity through the sweep frequency source module;

s3: echo signals of the resonant cavity are reflected back to a C2 port of the directional coupler through a coaxial feed end and are coupled to a detection amplifying circuit through a C3 port;

s4: obtaining a fitting curve of the corresponding relation between the resonant frequency and the rubber latex concentration through a directional coupler module and an analog amplification module;

s5: then, inquiring a fitting curve, and quickly measuring the concentration of the rubber latex;

s6: the existing scientific principle shows that the principle formula of the measurement is to measure the concentration of the rubber latex by the measurement principle that the dielectric constants of different media are different and the resonant frequencies are different.

Compared with the prior art, the invention has the beneficial effects that:

1. when the device is used, the column-shaped cavity is arranged in a semi-open mode, so that the rubber latex can be filled in the whole space of the column-shaped cavity, and compared with a resonant cavity perturbation method for measuring the liquid to be measured, the resonant cavity resonance frequency is greatly influenced by the liquid to be measured, and therefore the dielectric constant change of the liquid to be measured can be measured more sensitively and more accurately;

2. when the liquid pouring device is used, the liquid to be measured is poured and poured conveniently through the opening on the top surface of the cylindrical cavity, and the measuring process is convenient and quick;

3. when the coaxial feed-type resonant cavity is used, the coaxial structure formed by the metal probe and the metal cylinder is used for feeding the resonant cavity, common coaxial structures such as an SMA connector, an N-type connector and a BNC structure can be adopted for feeding, and the coaxial feed-type resonant cavity is convenient to realize and connect and low in cost.

Drawings

FIG. 1 is a schematic structural view of a cylindrical chamber according to the present invention;

FIG. 2 is a system composition diagram of the present invention;

FIG. 3 is a plot of the resonant frequency of a sweep frequency according to the present invention;

FIG. 4 is a graph of the resonant frequency versus concentration according to the present invention.

Reference numbers in the figures: 1. a coaxial probe; 2. an insulating medium; 3. a cylindrical cavity; 4. a coaxial signal feed-in structure; 5. a rubber latex container; 6. a sweep frequency source module; 7. a directional coupler module; 8. an analog amplification module; 9. an information processor.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-4, the present invention provides a technical solution: a microwave resonance structure and system for measuring the concentration of solutions such as rubber latex and the like comprises a cylindrical cavity 3, the cross section of the cylindrical cavity 3 is not limited to a cylindrical shape and can be a rectangle, a sphere, a trapezoid and the like, the top of the cylindrical cavity 3 is provided with an opening and is arranged in a semi-open manner, a round hole is formed in the bottom of the cylindrical cavity 3, the position of the round hole in the cylindrical cavity 3 is not limited to the central position of the cylindrical cavity 3, a coaxial probe 1 is arranged in the round hole inner cavity, an insulating medium 2 is sleeved on the outer side edge of the coaxial probe 1, the outer side of the insulating medium 2 is attached to the inside of the round hole, the coaxial probe 1 and the top end of the insulating medium 2 jointly extend to the inner cavity of the cylindrical cavity 3, the round hole is matched with the insulating medium 2, the installation of the insulating medium 2 and the round hole is more stable through the arrangement, the insulating medium 2 is arranged in a cylindrical manner, and the insulating medium 2 is matched with the coaxial probe 1, the bottom of the cylindrical cavity 3 is provided with a coaxial signal feed-in structure 4, and the coaxial signal feed-in structure 4 is composed of a coaxial probe 1 and the cylindrical cavity 3.

A microwave resonance system for measuring the concentration of a solution such as rubber latex comprises the following steps:

s1: pouring rubber latex with different concentrations into the cylindrical cavity 3;

s2: then measuring an echo signal of the resonant cavity through the sweep frequency source module 6;

s3: echo signals of the resonant cavity are reflected back to a C2 port of the directional coupler 7 through a coaxial feed end and are coupled to a detection amplifying circuit through a C3 port;

s4: obtaining a fitting curve of the corresponding relation between the resonant frequency and the rubber latex concentration through the directional coupler module 7 and the analog amplification module 8;

s5: then, inquiring a fitting curve, and quickly measuring the concentration of the rubber latex;

s6: the existing scientific principle shows that the principle formula of the measurement is to measure the concentration of the rubber latex by the measurement principle that the dielectric constants of different media are different and the resonant frequencies are different.

According to fig. 1 and 2: designing a resonant cavity structure, wherein the structural parameters are as follows, Dc =40mm, Hc =30mm, Lp =10mm, La =12mm, Dp =1.3mm and Df =4.2 mm; wherein the cylindrical cavity is made of aluminum, the metal probe is made of copper, and the insulating dielectric material is teflon; the coaxial connector of the resonant cavity adopts an SMA connector, and the cylindrical cavity 3 is immersed in the rubber latex container 5, so that the rubber latex is immersed in the hollow space inside the cylindrical cavity 3; the directional coupler module 7 in fig. 2 adopts a classical microstrip 4-port directional coupler, wherein C1 and C2 are input and output ends of the directional coupler, C3 is a coupling end of a C2 port and an isolation end of a C1 port, and C4 is a coupling end of a C1 port and an isolation end of a C2 port, where the C4 port is connected with a 50 ohm load; in fig. 2, the swept frequency source module 6 is connected to the input port C1 of the directional coupler module 7 through a coaxial cable, and is connected to the C2 port of the directional coupler on the SMA joint, and the microwave signal is fed through the C2 port. The sweep frequency range of the sweep frequency source covers the frequency ranges corresponding to the rubber latex with different concentrations. The frequency sweeping source can be realized by using various chips or structures such as DDS, VCO and the like, and the scheme is realized by using a VCO chip with PLL (phase locked loop), as shown in figure 2. The scanning frequency range is 1GHz-3GHz, and the scanning frequency interval is 1 MHz. The swept frequency power need not be too high, with the goal that the echo power is above the power detection sensitivity of the detector. Considering that the resonant peak at the resonant frequency is possibly-40 dB, the sensitivity of the detector is-60 dBm, the coupling degree of the directional coupler is-20 dB, considering a certain system margin, the emission power of the sweep frequency source is more than 0dBm, and the process introduces a feeding and detecting mode of a certain single frequency. In the aspect of system implementation, the ARM single chip microcomputer controls the VCO to realize frequency scanning, the output frequency of the frequency scanning chip is changed one by one, and the wave detector acquires the amplitude of the echo signal.

According to the illustration in fig. 3: the resonant frequency is typically a power low point and an extreme point. Because the measured data has noise and fluctuation, the measured curve is firstly filtered to smoothly filter the noise. Then, a power criterion is used for finding a point lower than the set power, and then whether the points on the left side and the right side of the point are higher than the point is judged, and if yes, the point is judged to be an effective point. When the number of points is not large, the resonance point found in fig. 3 is around 1.49GHz as the value of the resonance point frequency, which is the average of the number of points.

According to FIG. 4: by measuring the resonant frequency curve of a series of rubber latex with known concentration, a series of data of the rubber latex concentration versus resonant frequency can be formed. Fitting the curve by a quadratic polynomial to obtain a function curve of the corresponding relation between the resonance frequency and the concentration.

The working principle is as follows: when the device is used, rubber latex with different concentrations is poured into the cylindrical cavity 3, so that the inside of the cylindrical cavity 3 is filled with solution, then the echo signals of the resonant cavity are measured through the sweep frequency source module 6, the resonant frequencies of the latex with different concentrations can be obtained, the rubber latex with standard concentration is selected out from the resonant frequencies to measure the resonant frequency of the cavity, and a fitting curve of the corresponding relation between the resonant frequency and the rubber latex concentration is obtained through the directional coupler module 7 and the analog amplification module 8, so that the resonant frequency is obtained through measurement for the rubber latex with unknown concentration, and then the fitting curve is inquired, so that the concentration of the rubber latex can be quickly measured.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.