阅读说明：本技术 一种应用于高温高速等离子体内部磁场分布测量的耐高温磁场探针 (High-temperature-resistant magnetic field probe applied to high-temperature high-speed plasma internal magnetic field distribution measurement ) 是由 李小平 赵成伟 刘彦明 孙超 刘东林 韩明智 窦超 于 2019-07-22 设计创作，主要内容包括：本发明属于等离子体检测技术领域,公开了一种应用于高温高速等离子体内部磁场分布测量的耐高温磁场探针。磁场探针,用于接收空间磁场信号及高温高速等离子体内部磁场信号；支撑固定座,用于固定磁场探针的陶瓷介质及同轴接头的安装固定,保护磁场探针免受高速流动的等离子体的冲击破坏；同轴接头,用于向磁场探针传输信号。本发明解决了常规探针不能适应高温的问题,探针为共面波导形式,并且探针被耐高温陶瓷材料包覆,使得探针具有耐高温性能。探针采用双环结构,解决了单环不平衡结构造成的测量结果不对称的问题,并且展宽了频带范围。同时由于磁场探针是蚀刻在介电常数为4.2的介质基板上的,缩小为传统探针尺寸的<Image he="83" wi="294" file="DDA0002137953000000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>倍,提高了探针灵敏度。(The invention belongs to the technical field of plasma detection, and discloses a high-temperature-resistant magnetic field probe applied to high-temperature high-speed plasma internal magnetic field distribution measurement. The magnetic field probe is used for receiving a space magnetic field signal and a high-temperature high-speed plasma internal magnetic field signal; the supporting fixing seat is used for fixing the ceramic medium of the magnetic field probe and installing and fixing the coaxial connector, so that the magnetic field probe is protected from being damaged by impact of high-speed flowing plasma; and the coaxial connector is used for transmitting signals to the magnetic field probe. The invention solves the problem that the conventional probe can not adapt to high temperature, the probe is in a coplanar waveguide form, and the probe is coated by high-temperature-resistant ceramic materials, so that the probe has high-temperature resistance. The probe adopts a double-ring structure, so that the problem of asymmetric measurement results caused by a single-ring unbalanced structure is solved, and the frequency band range is widened. Meanwhile, because the magnetic field probe is etched on the dielectric substrate with the dielectric constant of 4.2, the size of the magnetic field probe is reduced to the size of the traditional probe And the sensitivity of the probe is improved.)

1. The utility model provides a be applied to high temperature resistant magnetic field probe that high temperature high speed plasma internal magnetic field distributes and measures which characterized in that, high temperature resistant magnetic field probe is provided with:

a magnetic field probe for receiving a spatial magnetic field signal; the magnetic field probe comprises a probe, a probe ground, a connecting line, a transition section ground and a high-temperature-resistant ceramic medium;

The probe is communicated with the transition section, and the probe ground is communicated with the transition section;

The magnetic field probe adopts a coplanar waveguide form, the probe is an inner conductor of the coplanar waveguide, and the probe ground is an outer conductor of the coplanar waveguide; adding a 180mm transition section between the probe and the coaxial connector;

the high-temperature resistant ceramic dielectric comprises two layers of plates, and a probe, a probe ground, a connecting line, a transition section and a transition section are etched on one side of one layer of dielectric plate; the two layers of dielectric plates sandwich copper cladding containing etching probes;

The supporting fixing seat is used for fixing the ceramic medium of the magnetic field probe and installing and fixing the coaxial connector, so that the magnetic field probe is protected from being damaged by impact of high-speed flowing plasma;

And the coaxial connector is used for transmitting signals to the magnetic field probe.

2. The high-temperature-resistant magnetic field probe as claimed in claim 1, wherein the high-temperature-resistant ceramic dielectric has a relative dielectric constant epsilon of 4.2, a single-layer dielectric plate thickness H of 1mm, and the ceramic dielectric withstands a temperature of < 1500 ℃ and a high temperature of 3000K.

3. The high temperature resistant magnetic field probe of claim 1, wherein the supporting fixture is comprised of a fixed cavity and a mounting flange.

4. the high temperature magnetic field resistant probe of claim 1, wherein the coaxial joint is comprised of a coaxial inner conductor, a coaxial outer conductor, and a coaxial flange;

the coaxial flange of the coaxial joint is fastened to the mounting flange by screws, and the coaxial inner conductor and the coaxial outer conductor are welded to the transition section and the transition section, respectively.

5. A high-temperature high-speed plasma internal magnetic field measurement system applying the high-temperature resistant magnetic field probe as claimed in any one of claims 1 to 4.

6. a spacecraft equipped with the high temperature high speed plasma internal magnetic field measurement of claim 5.

Technical Field

The invention belongs to the technical field of plasma detection, and particularly relates to a magnetic field measurement technology in high-temperature and high-speed plasma.

Background

Currently, the closest prior art is mainly the following:

1) The simple coaxial structure, namely, the outer conductor of the rigid coaxial cable is stripped, and the inner conductor is connected with a metal ring, so that a magnetic field signal can be received;

2) The probe constructed by Osofsky consists of two rings, which are shaped like magnetic quadrupoles and are used for 26.5-40GHz (1989) and 0.1-0.3GHz (1992), respectively, but the application range of the probe is very limited.

3) In 1995, Yingjie Gao and Ingo Wolff designed a new type of square magnetic field probe. The magnetic field probe can be used for measuring magnetic field distribution in planar high-frequency circuit, and is firstly arranged on a 3 × 20mm RT Duorid substrate (epsilon)_r2.2, h 0.5mm) and then bending the substrate 90 ° between the probe and the transmission line to measure the Z component of the magnetic field. The transmission line is connected to a semi-rigid coaxial cable and then to a network analyzer through an SMA adapter. The probe is processed by adopting a thin film technology, has the advantages of low manufacturing cost, stable working performance and the like, is very suitable for industrial application, but is not suitable for diagnosis of high-temperature and high-speed plasma.

4) In 1998, Yingjie Gao and Ingo Wolff developed electric dipole probes for measuring X and Y components of the electric field. Its head is an electric dipole and its tail is a coplanar waveguide transmission line. This structure was etched on a 1.38mm by 7.0mm ceramic substrate. The dipole arm is 100 μm long and the dipole is 20 μm wide. The characteristic impedance of the coplanar transmission line is 50 omega and is connected to a 50 omega semi-rigid coaxial cable. In order to avoid the induction field of the transmission line, the central conductor of the transmission line is isolated by non-conductive glue, and two grounding layers are bonded with the silver glue, so that the signals of the probe are symmetrically transmitted. To determine the electromagnetic fields radiated by electronic systems, a fully automated near field probe scanning measurement system was developed in IRSEEM (electronic embedded systems institute) by d. Such a probe is suitable for use with high temperature media, but is not suitable for use with high velocity flowing plasma.

Combining the above research results of magnetic field probes, all the probes in the past cannot be applied to diagnosis in high-temperature and high-speed plasma flow, and the problems in the prior art are as follows: the magnetic field probe needs to withstand high temperature operation of 3000K for a short time (about 1 second) and can withstand the impact of a plasma stream of about mach 1.

The difficulty of solving the technical problems is as follows: 1) the magnetic field probe needs to withstand a high temperature operation of 3000K for a short time (about 1 second); 2) can bear the impact of the plasma flow with about Mach 1, and the structural strength needs to be good.

The significance of solving the technical problems is as follows: the magnetic field measurement can be carried out on the interior of the high-temperature high-speed plasma, so that the high-temperature high-speed plasma can be diagnosed and measured in detail. Has very important significance for researching the interaction of the high-temperature plasma and the electromagnetic field.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a high-temperature-resistant magnetic field probe applied to the measurement of the magnetic field distribution in high-temperature high-speed plasma.

the invention is realized in such a way that a high temperature magnetic field resistant probe is provided with:

A magnetic field probe for receiving a spatial magnetic field signal;

The supporting fixing seat is used for fixing the ceramic medium of the magnetic field probe and installing and fixing the coaxial connector, so that the magnetic field probe is protected from being damaged by impact of high-speed flowing plasma;

And the coaxial connector is used for transmitting signals to the magnetic field probe.

Further, the magnetic field probe comprises a probe, a probe ground, a connecting line, a transition section ground and a high-temperature-resistant ceramic medium;

The probe is communicated with the transition section, and the probe ground is communicated with the transition section;

Two magnetic field rings are formed by adding connecting wires;

The magnetic field probe adopts a coplanar waveguide form, the probe is an inner conductor of the coplanar waveguide, and the probe ground is an outer conductor of the coplanar waveguide; adding a 180mm transition section between the probe and the coaxial connector;

The high-temperature resistant ceramic dielectric is divided into two layers of plates, and the probe, the probe ground, the connecting line, the transition section and the transition section are etched on one side of one layer of dielectric plate; the two dielectric sheets sandwich copper clad including an etching probe or the like.

Furthermore, the high-temperature resistant ceramic dielectric has a relative dielectric constant epsilon of 4.2, the thickness H of the single-layer dielectric plate is 1mm, and the ceramic dielectric bears the temperature of less than 1500 ℃, so that the high-temperature resistant ceramic dielectric can bear the high temperature of 3000K in a short time.

Furthermore, the supporting and fixing seat is composed of a fixing cavity and a mounting flange.

Further, the coaxial connector consists of a coaxial inner conductor, a coaxial outer conductor and a coaxial flange;

The coaxial flange of the coaxial joint is fastened to the mounting flange by screws, and the coaxial inner conductor and the coaxial outer conductor are welded to the transition section and the transition section, respectively.

The invention also aims to provide a high-temperature high-speed plasma internal measuring system applying the high-temperature resistant magnetic field probe.

another object of the present invention is to provide a spacecraft equipped with the high temperature high speed plasma internal measurement system.

in summary, the advantages and positive effects of the invention are: the invention provides a high-temperature-resistant magnetic field probe applied to high-temperature high-speed plasma internal magnetic field distribution measurement, which solves the problem that the conventional probe cannot adapt to high temperature. The probe adopts a double-ring structure to solve the problem of unbalanced junctionThe measurement result is asymmetric, and the frequency band range is widened by nearly 1 time. The magnetic field probe is etched to have a dielectric constant ∈_r4.2, according to the theory of reducing the length of the dielectric line, the size is reduced to the size of the traditional probeand the receiving sensitivity of the probe is improved. The magnetic field probe is used for receiving magnetic field information and is a magnetic field ring. The magnetic field probe is of a ring structure and receives magnetic field information by measuring the magnetic field flux flowing into the ring structure.

The invention uses the coplanar waveguide form to improve the traditional coaxial probe, etches the coplanar waveguide on one surface of the high-temperature resistant ceramic substrate, uses another ceramic substrate with the same size to clamp the coaxial probe in the middle, and adopts a special high-temperature resistant compression joint process to bond the two layers of ceramic substrates into a whole, thereby not only enhancing the structural strength of the single-layer ceramic substrate, but also avoiding the direct contact between the magnetic field probe and the high-temperature plasma, and further avoiding the possibility of the plasma being polluted. The traditional magnetic field probe is only provided with one ring structure, and the magnetic field probe forms two rings by adding a section of connecting wire, so that the sensitivity of the magnetic field probe is improved. Because the size of the plasma region is large, the coaxial connector for transmitting signals for the probe cannot resist the high temperature of thousands of degrees centigrade, a transition section is additionally arranged between the coaxial connector and the magnetic field probe, so that the probe is positioned at the core position of plasma to diagnose the plasma, and the coaxial connector can be positioned outside the plasma to avoid the high temperature damage of the plasma. Meanwhile, the high-temperature plasma has a fast flowing speed, and if the probe is placed in the plasma alone, the probe can be broken. Therefore, the supporting and fixing seat is added outside the probe, so that the probe is protected, and meanwhile, a fixed position is provided for the coaxial connector.

Drawings

FIG. 1 is a schematic structural diagram of a high-temperature-resistant magnetic field probe provided in an embodiment of the present invention;

in the figure: (a) the integral structure of the high-temperature resistant magnetic field probe is schematically shown along the yoz surface; (b) the whole structure of the high-temperature resistant magnetic field probe is schematically shown along the xoz surface; (c) the front end part of the high-temperature resistant magnetic field probe is schematically shown along the yoz surface; (d) the front end part of the high-temperature resistant magnetic field probe is enlarged along a yoz plane; (e) the front end part of the high-temperature resistant magnetic field probe is schematically shown along the xoz surface; (f) the coaxial connector part of the high-temperature-resistant magnetic field probe is schematically shown along the yoz surface; (g) the coaxial connector part of the high-temperature-resistant magnetic field probe is schematically illustrated along the xoz surface;

FIG. 2 is a schematic diagram of an overall structure of a high-temperature-resistant magnetic field probe according to an embodiment of the present invention;

In the figure: (a) marking the overall size of the high-temperature resistant magnetic field probe along a yoz plane; (b) marking the size of the front end part of the high-temperature resistant magnetic field probe along a yoz plane; (c) the size of the front end part of the high-temperature resistant magnetic field probe is marked along the xoz surface; (d) the size of the tail end of the transition section of the high-temperature-resistant magnetic field probe is marked along the yoz surface.

FIG. 3 is a schematic diagram comparing a high temperature magnetic field resistant probe provided by an embodiment of the present invention with a conventional probe;

In the figure: (a) a simulation result diagram of reflection coefficients of the high-temperature-resistant improved probe and a traditional probe (without a connecting wire 1-3); (b) magnetic field probe isolation simulation results; (c) the magnetic field normalization distribution result of the magnetic field annular structure along the Y direction in the normal direction; (d) and normalizing the distribution result of the magnetic field along the Z direction in the normal direction of the magnetic field annular structure.

Fig. 4 is a diagram of simulation results of S parameters of a transition section of an electromagnetic probe according to an embodiment of the present invention.

fig. 5 is a three-dimensional directional diagram of a magnetic field probe pattern provided by an embodiment of the present invention.

in fig. 1 and 2: 1. a magnetic field probe; 1-1, a probe; 1-2, probe ground; 1-3, connecting wires; 1-4, transition section; 1-5, transition section; 1-6, high temperature resistant ceramic medium; 2. a supporting fixed seat; 2-1, fixing the cavity; 2-2, installing a flange; 3. a coaxial joint; 3-1, a coaxial inner conductor; 3-2 coaxial outer conductors; 3-3, coaxial flange.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Aiming at the problems in the prior art, the invention provides a high-temperature-resistant magnetic field probe applied to the measurement of the magnetic field distribution in high-temperature high-speed plasma, and the invention is described in detail with reference to the attached drawings.

As shown in fig. 1, the high-temperature resistant magnetic field probe provided by the embodiment of the invention is composed of a magnetic field probe 1, a supporting fixing seat 2 and a coaxial connector 3.

the magnetic field probe 1 adopts a coplanar waveguide form, and the magnetic field probe 1 is clamped between two layers of ceramic media 1-6, so that the direct contact between the magnetic field probe 1 and high-temperature plasma is avoided. Meanwhile, transition sections 1-4 are added between the magnetic field probe 1 and the coaxial connector 3 to avoid the direct contact of the coaxial connector 3 and high-temperature plasma. And the magnetic field probe 1 working at the frequency of 2-12GHz and the transition section 1-4 of the corresponding working frequency are directly integrated, so that the processing and the integration are convenient to realize. The high temperature plasma has a fast flow rate and may break if the probe is placed in the plasma alone. Therefore, the supporting and fixing seat is added outside the probe, so that the probe is protected, and meanwhile, a fixed position is provided for the coaxial connector.

In the preferred embodiment of the invention, the magnetic field probe 1 is used to receive a magnetic field signal and transmit the signal to the coaxial connector 3 through the transition sections 1-4 and then to a receiver or a test vector network analyzer.

In the preferred embodiment of the invention, the supporting fixing seat 2 is used for fixing the ceramic medium of the magnetic field probe 1, protecting the probe from being damaged by the impact of high-speed flowing plasma, and ensuring that the magnetic field probe 1 can stably work.

in the preferred embodiment of the invention, the transition sections 1-4 and the transition sections 1-5 are welded to the coaxial inner conductor 3-1 and the coaxial outer conductor 3-2, respectively.

in the preferred embodiment of the present invention, the coaxial connector 3 is used for receiving the signal transmitted by the magnetic field probe 1.

In a preferred embodiment of the invention the coaxial joint is fixed to the mounting flange 2-2.

As shown in figures 1 and 2, the magnetic field probe of the present invention is optimized to work at a frequency of 2-12GHz, and the size of the probe part is 3mm x 2mm, which is less than the requirement of 5mm of space precision; the geometric dimension parameters of the specific magnetic field probe structure are shown in table 1.

TABLE 1 magnetic field Probe construction geometry size (units/mm)

symbol	Size of	Symbol	Size of	Symbol	Size of
						LL1	200	L1	2	W1	0.2
LL2	20	L2	1	W2	0.4
						LL3	5	L3	16	W3	2
WW1	φ20	H1	1	W4	4
						WW2	φ40	H2	0.035	W5	1
				W6	1.4
										W7	8
				W8	14

The technical effects of the present invention will be described in detail with reference to simulations.

the magnetic field probe of the invention is modeled, simulated and optimized by using commercial simulation software (CST), the simulation result is shown in figures 3-5, and the S parameter of the magnetic field probe is simulated and calculated in the frequency range of 1-20 GHz. Under the condition of the same ring size L1, the return loss of the probe of the high-temperature-resistant CPW joint is obviously improved compared with that of the conventional coaxial probe, and as shown in a figure 3(a), the probe has better return loss compared with the conventional probe.

The isolation of the probe, also called the directional selectivity of the probe, is an important performance parameter of the magnetic field probe for magnetic field polarization selection. Using CST software to perform modeling simulation, adopting plane wave to irradiate the probe, adjusting the direction of a plane wave magnetic field to form included angles of 0 degree, 45 degrees and 90 degrees with an inner conductor of the probe respectively, arranging a voltage monitor at the tail end of the probe, and reading an output voltage value at the tail end of the probe, wherein the simulation frequency is 6GHz, and the simulation result is shown in figure 3 (b). As can be seen from the simulation graph, the isolation degree is about 50dB, and the good magnetic field distinguishing capability of the probe is verified. And then, analyzing and calculating the sensitivity of the probe, irradiating the probe by adopting the plane waves under the same condition to ensure that the magnetic field direction of the plane waves is vertical to the plane of the square ring of the probe, reading the output voltage value of the tail end, and converting the output voltage value of the tail end into a power value, namely the sensitivity of the probe. The simulation result shows that the terminal output voltage value is 11.5dBmV at 6GHz, and the sensitivity is about-35.5 dBm; indicating good directional selectivity of the probe.

And scanning and simulating the microstrip line by scanning the probe, and placing the probe at a position 1mm above the surface of the microstrip line, wherein the normal direction of the plane where the microstrip line is located is a Z axis, the plane where the microstrip line is located is an XOY plane, and the microstrip line is along the direction of a Y axis. And (3) enabling the probe to be placed in a position parallel to the Z axis, rotating the probe around the Z axis, and enabling the plane where the square ring of the probe is located to be vertical to the X axis and the Y axis respectively so as to obtain the magnetic field distribution in the X direction and the Y direction. The probe sequentially performs scanning measurement along the X axis from left to right, and simulation results are shown in fig. 3(c) and fig. 3 (d). In which fig. 3(c) shows the X-direction magnetic field distribution and fig. 3(d) shows the Y-direction magnetic field distribution. Hx and Hy represent the true magnetic field distribution in the X and Y directions, respectively, normal to the probe loop structure. The magnetic field distribution measured by the probe is compared with the real distribution, and the magnetic field distribution and the real distribution are matched.

In order to avoid the coaxial connector from being damaged by the high temperature plasma, a 180mm transition section is added between the magnetic field probe and the coaxial connector, and the transition section is also simulated in CST software, wherein Port1 is a transition section Port located at the probe, and Port2 is a Port located at the coaxial connector, and the simulation result is shown in FIG. 4. From simulation results, the transmission performance is good, the return loss is basically less than-15 dB, and the transmission loss is small. The probe aims to receive a magnetic field signal of a space, a simulated three-dimensional directional diagram of the probe is shown in figure 5, and as can be seen from a simulation result, the probe has strong radiation performance around the probe.

In summary, the CST 2018 simulation software is used for antenna simulation, the optimally designed magnetic field probe has a better reflection coefficient than the conventional magnetic field probe, and has better sensitivity and isolation performance, and the design results are shown in fig. 3-5. The result shows that the designed probe has better return loss than the traditional probe, and shows that the receiving sensitivity is higher; meanwhile, the probe realizes the isolation of about 50dB, the sensitivity is about-35.5 dBm, and the excellent performance of the probe is improved by nearly 10dB compared with the traditional magnetic field probe. Meanwhile, in order to verify the actual performance of the probe, the probe is subjected to simulation test on the upper surface of the microstrip line, and the result shows that the measurement result of the probe is very similar to theoretical calculation, so that the real value of the probe is verified. The traditional probe only focuses on electrical performance, the structural strength is poor, the probe is protected by the fixing seat, the structural strength of the probe is greatly enhanced, and the electrical performance is basically not influenced, so that the pioneer is opened up for the use of the probe in a high-speed flow field.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.