CN113314852A - Plasma modulator and electromagnetic wave vector microscopic sensor - Google Patents
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Abstract
The invention relates to a plasma modulator and an electromagnetic wave vector microscopic sensor, which perform wave front modulation on the poynting vector and energy flux density distribution of an incoming wave through an electromagnetic property adjustable medium such as plasma and a space shaper, introduce the incoming wave into an antenna by utilizing the single or multi-path modulator, establish an uncorrelated full rank matrix, increase the observation freedom of a system, and solve and image the information of quasi-parallel electromagnetic wave amplitude, phase, azimuth angle, pitch angle and the like; when the modulator is used by being more than or equal to the two paths of modulators, the three-dimensional imaging of the incoming waves can be realized by combining the spatial distance of the modulators, and the three-dimensional imaging has the characteristics of staring, super-resolution capability and super-aperture. Compared with the prior art, the invention can be directly applied to the prior radar, electronic reconnaissance, radio telescope, communication and other systems by adding the wave front modulation device on the prior antenna and matching with an inversion algorithm, thereby realizing the single-beam internal staring three-dimensional super-resolution imaging of the incoming waves.
Description
Technical Field
The invention relates to the field of plasma, electromagnetic field, electromagnetic wave and electronic reconnaissance, in particular to a plasma modulator and an electromagnetic wave vector microsensor.
Background
The fine resolution technology of electromagnetic signals is the basis of various fields such as modern electronic investigation, unmanned driving, flight detection and the like, and is also a hot point problem which is commonly concerned by the scientific research field and the industrial field. The resolution capability limit of the traditional radar and antenna system is limited by the physical aperture surface of the antenna, and a plurality of same-frequency electromagnetic signals simultaneously received in the main beam range are difficult to be resolved, and only the comprehensive effect of the signals can be obtained. In order to improve the resolution capability of an antenna system, the existing solutions include hardware means such as increasing the physical size of an antenna, a very long baseline, a synthetic aperture and software means such as a super-resolution algorithm. Although the methods can improve the resolution capability of the antenna system to a certain extent, the fine resolution problem of the same-frequency multi-target approximate parallel incoming wave signals is still difficult to solve, and the cost is high.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, improve the resolving power of the system in the azimuth direction and the pitch direction under the condition of not changing the physical structures of a radar and an antenna system as much as possible, and provide a plasma modulator and an electromagnetic wave vector microsensor.
The invention provides a wave front plasma modulator based on a special shaped plasma, which aims at parallel plane electromagnetic waves to carry out nonlinear space modulation, can change the poynting energy flux density distribution in the space by utilizing an electric regulation control mode, introduces waves into an antenna by utilizing a single or multi-path modulator, establishes an uncorrelated full-rank matrix, increases the observation freedom degree of a system, and solves and images the information of the quasi-parallel electromagnetic waves such as amplitude, phase, azimuth angle, pitch angle and the like; when the modulator is used by being more than or equal to the two paths of modulators, the three-dimensional imaging of the incoming waves can be realized by combining the spatial distance of the modulators, and the three-dimensional imaging has the characteristics of staring, super-resolution capability and super-aperture. According to the invention, the single-channel plasma correspondingly completes the hyperfine resolution of the azimuth dimension or the pitch dimension, and the three-dimensional target resolution can be simultaneously completed by expanding the plasma modulation structure into a double-channel cross or sphere and combining the pulse compression technology. The invention can not only realize super-resolution effect on an antenna system with fixed physical caliber, but also can be used for greatly reducing the physical caliber of the required antenna under the condition of keeping the resolution precision of the system unchanged. Meanwhile, the invention can adjust the plasma shaping and state according to the requirements and has multi-band universality.
Once the design of a conventional antenna system is completed, the fundamental resolution of the system in the azimuth direction is also determined. The microscopic identification imaging technology starts with the incident electromagnetic wave at the front end of the antenna, and completes the modulation of the aligned linear electromagnetic vector through the nonlinear modulation equipment, thereby amplifying the weak nonlinear condition in the vector signal to a certain extent and providing enough implicit conditions for the accurate positioning of the target.
The purpose of the invention can be realized by the following technical scheme:
a plasma modulator for electromagnetic signal target resolution comprises a plasma, a physical constraint structure main body of the modulator, filling gas and a modulator excitation structure, wherein the plasma is positioned in the physical constraint structure main body of the modulator and is constrained and shaped by the physical constraint structure main body of the modulator; the modulator physical constraint structure body is internally sealed and filled with the filling gas, and the modulator excitation structure is connected to the outer side of the modulator physical constraint structure body;
the plasma modulator is placed in front of the receiving antenna and aligned with the electromagnetic incoming waves, nonlinear wave front modulation is carried out by the plasma, and the receiving antenna carries out target resolution according to signals processed by the plasma modulator.
Further, the nonlinear wave front modulation effect of the plasma on the electromagnetic incoming wave is realized by adjusting the relative dielectric constant epsilon of the plasmarThe plasma frequency omega is controlled through electric regulationpTo realize the relative dielectric constant epsilon of the plasmarAnd (4) adjusting.
Further, the plasma is a non-magnetized cold plasma, the plasma of which is a non-magnetized cold plasmaRelative dielectric constant of daughter ∈rThe regulation expression of (a) is:
in the formula, ωpIs plasma frequency, omega is incoming wave angular frequency, j is imaginary unit, upsilon is collision frequency; the plasma frequency omegapThe calculation expression of (a) is:
in the formula, neIs electron density, e is electron charge, meIs electron mass,. epsilon0Is the dielectric constant in vacuum.
Furthermore, the material of the physical constraint structure body of the modulator is quartz or plastic.
Further, the cross-sectional shape of the main body of the physical constraint structure of the modulator is a continuous curve and has the shape of a convex structure;
the minimum diameter of the cross section of the physical constraint structure body of the modulator is 2 to 3 times of the aperture of the receiving antenna.
Further, the filling gas is a rare gas.
Further, the modulator excitation structure comprises a coupling structure, an impedance matching structure and a feed structure which are connected in sequence, wherein the coupling structure is connected to the outer side of the main body of the physical constraint structure of the modulator.
Further, the coupling structure is in including the parcel the copper material in the modulator physics restraint structure main part outside, the impedance matching structure includes series element and parallel element, the feed structure is the coaxial line, copper material, series element and coaxial line establish ties in proper order, parallel element with the coaxial line is parallelly connected.
The invention also provides a vector microsensor employing a plasma modulator for object resolution of electromagnetic signals as described above, comprising a receiving system and said plasma modulator,
the plasma modulator is positioned in front of the receiving system, and the cross section area of a physical constraint structure body of the modulator in the plasma modulator covers the antenna main lobe angle of the receiving system;
the weak correlation state number of the plasma modulator is larger than or equal to the division number of the target in the area to be measured, the state number refers to the same target unit, the difference of the amplitude and the phase of the signal received by the receiving antenna when the power of the excitation source is different is more than one order of magnitude of distinguishable precision of the receiving system, and the number of the state number depends on the power range of the excitation source, the physical parameters of the plasma, the shaping structure of the physical constraint structure main body of the modulator, the measurement precision of the receiving system and the background noise of an application scene.
Furthermore, the receiving system is a single-path antenna or a multi-path antenna, when the receiving system is a multi-path antenna, each path of antenna is correspondingly provided with one plasma modulator, and the excitation of each plasma modulator is in the same phase.
Compared with the prior art, the method mainly aims at the microscopic identification imaging of the multi-view standard parallel incoming waves, and can greatly improve the resolution capability of the original radar and antenna system. Meanwhile, the invention not only can distinguish a plurality of targets in the range of the main lobe of a single wave beam, but also can identify a false target or the multipath phenomenon of a single target on the basis of the targets. The invention realizes the super resolution of a plurality of targets in the range of the main lobe by amplifying the information and carrying out special processing on the algorithm on the basis of simultaneously utilizing the weak direction (space) information in the electromagnetic vector signal. Similarly, when the resolution of multiple targets is achieved, more detailed information of the targets can be further obtained by combining the prior art. Meanwhile, the plasma electromagnetic vector microscopy in the invention has the potential of challenging the electromagnetic diffraction limit.
Drawings
Fig. 1 is a schematic diagram of a typical application scenario of a plasma modulator, in which a transmitting antenna is used to simulate co-frequency echo signals instead of a target. The transmitting antennas are all located in the range of the main lobe angle of the receiving antenna, a plasma modulator is added at the near field of the receiving antenna, echo signals in multiple states are recorded, and the echo signals are compared with a reference antenna, so that multi-target resolution can be completed. The reference antenna and the receiving antenna are on the same vertical axis in the drawings and are not shown. The reference antenna may be located anywhere near the receive antenna, behind the non-plasma screen.
Fig. 2 is a schematic physical structure diagram of a cylindrical plasma modulator, in which a capillary tube with a diameter of 5mm is connected to a cylindrical quartz cavity as a gas filling port, and after the restart of the rare gas is completed, the rare gas is fused near the root, which is not shown in the figure to prevent misinterpretation. The outer diameter of the cylindrical quartz cavity is 5cm (related to the caliber of a receiving antenna and not limited to a certain size), the length is not limited, the wall thickness of the quartz cavity is 1mm, and gas filled in the constraint cavity is used for exciting to generate plasma.
FIG. 3 is a schematic diagram of an excitation mode of a plasma modulator, in which a rare gas is confined in a quartz cavity, a thin copper sheet with a width of 3-5 cm is wrapped outside the quartz cavity, the copper sheet is connected with an inner conductor of a coaxial line through an inductor, and a parallel capacitor is added between the inner conductor and the outer conductor of the coaxial line.
FIG. 4 is a schematic diagram of a shaped cross section of a parallel plane electromagnetic wave incident to a plasma, wherein the shaped cross section can be a circle, an ellipse, a parabola or other convex functions with continuous gradual curvature, and the shaped shape is determined by the processing shape of a quartz confinement cavity outside the plasma.
Fig. 5 is a schematic diagram of energy flux density distribution in space after parallel plane waves pass through hyperbolic plasma, an incident surface and an exit surface of electromagnetic waves of a hyperbolic plasma confinement cavity are hyperbolic cylindrical surfaces, and energy flux densities of the parallel plane waves at different space azimuth angles after the parallel plane waves pass through the hyperbolic plasma confinement cavity are in nonlinear change.
Fig. 6 is a schematic diagram of energy flux density distribution in space after parallel plane waves pass through a paraboloid-shaped plasma column, an incident surface of electromagnetic waves of the paraboloid-shaped plasma confinement cavity is a paraboloid-shaped cylinder, an emergent surface of the electromagnetic waves is a plane, and energy flux densities of the parallel plane waves in different space azimuth angles after the parallel plane waves pass through the paraboloid-shaped plasma confinement cavity are nonlinearly changed.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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 some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. 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.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only used for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
Example 1
The embodiment provides a plasma modulator for electromagnetic signal target resolution, which utilizes specially shaped plasma to realize fine resolution of a plurality of same-frequency targets in a main beam range of a receiving antenna, performs nonlinear wavefront modulation by aligning parallel electromagnetic incoming waves, observes a change rule of amplified poynting vector, and combines a designed imaging algorithm to complete microscopic identification of a target to be detected.
The plasma modulator comprises a plasma, a modulator physical constraint structure main body, filling gas and a modulator excitation structure, wherein the plasma is positioned in the modulator physical constraint structure main body and is constrained and shaped by the modulator physical constraint structure main body; the modulator physical constraint structure body is internally sealed and filled with the filling gas, and the modulator excitation structure is connected to the outer side of the modulator physical constraint structure body;
the plasma modulator is placed in front of the receiving antenna and aligned with the electromagnetic incoming waves, nonlinear wave front modulation is carried out by the plasma, and the receiving antenna carries out target resolution according to signals processed by the plasma modulator.
The nonlinear wavefront modulation effect of the plasma on the electromagnetic incoming wave is realized by adjusting the relative dielectric constant epsilon of the plasmarThe plasma frequency omega is controlled through electric regulationpTo realize the relative dielectric constant epsilon of the plasmarAnd (4) adjusting.
Specifically, the plasma modulator is mainly composed of three parts: the modulator physical constraint structure body is filled with gas and is provided with a modulator excitation structure;
the main body of the constraint structure is characterized by being made of quartz materials, plastic and other materials are not excluded, the main body is cylindrical and spherical, other shapes with continuous curves and convex structures on cross sections are not excluded, the size of the main body is determined by the aperture of a receiving antenna under an application scene, the diameter of the cross section is 2-3 times of the aperture, and other approximate sizes are not excluded;
the main body of the filling gas in the constraint structure is argon, oxygen, nitrogen or mixed gas, other rare gases are not excluded, the gas proportion is related to an excitation mode, vacuum equipment and a constraint shape, argon is changed from zero to ninety-nine percent, when the filling gas in the constraint structure is sealed, the pressure in the tube is changed from 0.0001Pa to 1000Pa, and other atmosphere proportion and pressure change are not excluded;
the modulator excitation structure comprises a coupling structure, an impedance matching structure and a feed structure, the coupling structure is a 3-5 cm wide copper sheet wrapping constraint structure, other sizes or copper ring winding and the like are not eliminated, the impedance matching structure comprises series elements and parallel elements, specific numerical values depend on the coupling structure and frequency selection, the feed structure is a coaxial line, single-channel plasma correspondingly completes super resolution of azimuth dimension and pitching dimension, the plasma modulation structure is expanded into a double-channel cross or spherical shape, three-dimensional target super resolution can be simultaneously completed, and the super-aperture characteristic is achieved.
The present embodiment also provides a vector microsensor employing a plasma modulator for object resolution of electromagnetic signals as described above, comprising a receiving system and said plasma modulator,
the vector microscopic sensor comprises two items: the modulator is matched with a receiving system, and the state of the modulator is related to the target area;
the modulator and the receiving system are matched and characterized in that a physical structure of the modulator is adjacent to a receiving antenna and is positioned in front of the receiving antenna, a shaping section of the modulator can cover a main lobe angle of the antenna, the modulation effect is concentrated on the section where the shaping surface is positioned, the receiving antenna can be a single path or a plurality of paths, each path is matched with a modulator structure during the plurality of paths, the excitation of the multi-path modulator is in the same phase, the receiving antenna can work in cooperation with a reference antenna at the same time, and the reference antenna is positioned outside the influence range of the modulator and is unchanged relative to the receiving antenna;
the relation between the state of the modulator and the target area is that the number of weak correlation states of the modulator is more than or equal to the number of target divisions of an area to be measured, the state number of the modulator refers to the same target unit, the difference of the amplitude and the phase of signals received by a receiving antenna when the power of an excitation source is different is more than one order of magnitude of distinguishable accuracy of a receiving system, and the number of the states depends on the power range of the excitation source, the physical parameters of plasma, the forming structure of a constrained cavity, the measurement accuracy of the receiving system and the background noise of an application scene;
the vector microsensor can be applied to the traditional radar and antenna, such as systems of staring imaging, electronic reconnaissance, radio telescope and the like, provides staring and super-resolution capabilities, has a super-aperture effect and is universal in frequency band.
The application process of the present embodiment is described in detail below.
The typical application scenario of the invention is shown in fig. 1, a plurality of targets to be measured exist in the main beam range of the receiving antenna (target echoes are replaced by the transmitting antenna), and the plasma wave front modulator is added at the near field in front of the aperture surface of the receiving antenna, so that the effect of wave front modulation can be realized by controlling plasma by means of a radio frequency source, and the system design target is achieved.
Specifically, the plasma wave front modulator is composed of a cylindrical quartz cavity (not limited to a cylinder, but also can be other shapes) as a basic physical structure of the modulator, and a capillary tube with the diameter of 5mm is connected to the quartz cavity and used for filling gas into the quartz cavity. After the gas filling is completed, it is fused off to seal the gas in the tube, as shown in fig. 2. The cylindrical quartz cavity structure is externally wrapped with a layer of coupling copper sheet and is connected to the coaxial line inner conductor through a series inductor, and meanwhile, a capacitor is connected in parallel at the connection part of the inductor and the coaxial line and the other end of the capacitor is connected with the coaxial line outer conductor, as shown in figure 3. Compared with the coaxial line inner conductor direct-coupled copper sheet, the excitation structure obviously reduces port reflection, and meanwhile, the excitation structure is matched with the feed copper sheet more closely, so that energy loss and heat productivity in the line can be effectively reduced. The specific parallel capacitance and the series inductance need to be determined according to the parameters of the plasma to be excited, and the coaxial ports on the same side of the excitation source can be directly connected with a radio frequency source or a matcher.
According to the basic theory of plasma, the interaction effect with electromagnetic waves is mainly represented by the dielectric constant epsilon. For the non-magnetized cold plasma used in this example, the relative dielectric constant is as follows:
in the formula, ωpIs the plasma frequency, omega is the incoming wave frequency, j is the imaginary unit, and upsilon is the collision frequency.
The invention passes electricityRegulating and controlling plasma frequency omegapTo realize the relative dielectric constant epsilon of the plasmarThe selection of a plurality of non-correlated states is obtained. The plasma frequency is controlled by different RF source output powers, wherein the output power mainly changes the plasma ionization degree.
The invention realizes the excitation and control of the plasma by ionizing the gas by utilizing an external radio frequency source and a corresponding matching structure. The formula for calculating the plasma frequency is as follows:
in the formula, neIs electron density, e is electron charge, meIs electron mass,. epsilon0Is the dielectric constant in vacuum.
It can be seen that the plasma frequency is mainly determined by the concentration of ions after ionization. Since the low-pressure gas has low density and is easy to ionize, and the high-pressure gas has high density and is difficult to ionize, it is important to study and control the relationship between the gas ionization rate and the excitation power and the gas density.
The plasma frequency mainly depends on the ion concentration, and the ion concentration is determined by the ionization degree and the particle density, and the ionization degree and the particle density are interdependent and mutually influenced. In the design and preparation of the plasma modulator, the selection of the pressure in the tube not only needs to reversely deduce the pressure under an ideal gas equation according to the required particle concentration, but also needs to consider whether the ionization degree can meet the requirements at different powers.
In this embodiment, the gas to be excited filled in the quartz tube is a rare gas, such as a monoatomic molecular argon gas. Since the dissociation energy of a gas generally composed of diatomic molecules is large, it is difficult to form and maintain a plasma state at low power; the electron collision frequency of the rare gas is high; meanwhile, argon is also an inert gas with the largest content in the air, accounts for 1 percent of the air, is colorless, tasteless, nontoxic, safe, easy to obtain and cheap; in addition, the interference generated by the relatively simple emission spectrum of the argon is very little, and the concentration of the plasma can be increased by properly increasing the proportion of the argon under the same excitation power, so that the property of the plasma is favorably improved. The oxygen gas may weaken the recombination rate of the plasma, making the plasma stable. The stable high-concentration plasma can be obtained by reasonably adjusting the atmosphere proportion of argon and air (oxygen) with lower energy consumption and power.
The electromagnetic vector microscopy of the present embodiment is achieved by shaped plasma, the most basic shape being circular. The quasi-parallel plane electromagnetic wave transmits through the shaped plasma, and the energy flux density is non-linearly dispersed in the rear area of the plasma. The plasma carries out nonlinear modulation on electromagnetic signals in the main lobe angle, and a foundation is provided for multi-target azimuth hyperfine resolution. As shown in fig. 4, the micro-modulation effect of the plasma is mainly focused on the cross section where the shaping is located, i.e. one-dimensional azimuth direction or pitch direction. If a two-dimensional modulation effect needs to be obtained, only two plasma modulators need to be placed in front of and behind a cross mode (or a spherical plasma modulation structure is directly prepared), attention needs to be paid to ensuring that a receiving antenna is located in a coverage range of a cross area, and a three-dimensional resolution effect can be achieved by matching with a pulse compression technology. As shown in fig. 5 and 6, the shape of the plasma is not limited to a circular shape, and various shapes having a convex lens-like effect can be used as the shape of the plasma. The shaping cavity of the spherical-shaped spherical-surface cylindrical surface has the requirement of having continuously gradually-changed curvature, and the shape of the shaping cavity can be a series of shapes with continuously-changed curvature, such as a cylindrical shape, a spherical shape, a hyperbolic column shape, a parabolic column shape and the like. The change of the shaping structure does not affect the modulation effect of the plasma, but affects the number of non-relevant or weakly relevant states, thereby reducing or improving the resolving power of the plasma modulator.
The size of the plasma modulation device of this embodiment is not fixed, and is mainly related to the size of the aperture of the receiving antenna. The diameter of the plasma modulator must be such that it completely covers the corresponding size of the main beam of the antenna, while the diameter must not be too large or the number of active states is reduced. Generally speaking, the diameter of the plasma is 2-3 times of the physical aperture of the antenna, and the length in the other direction is preferably larger than the diameter of the plasma to prevent the modulation effect from being affected.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.
Claims (10)
1. A plasma modulator for electromagnetic signal target resolution is characterized by comprising a plasma, a physical constraint structure main body of the modulator, filling gas and a modulator excitation structure, wherein the plasma is positioned in the physical constraint structure main body of the modulator and is constrained and shaped by the physical constraint structure main body of the modulator; the modulator physical constraint structure body is internally sealed and filled with the filling gas, and the modulator excitation structure is connected to the outer side of the modulator physical constraint structure body;
the plasma modulator is placed in front of the receiving antenna and aligned with the electromagnetic incoming waves, nonlinear wave front modulation is carried out by the plasma, and the receiving antenna carries out target resolution according to signals processed by the plasma modulator.
2. A plasmon modulator for object resolution of electromagnetic signals as defined in claim 1 wherein the effect of nonlinear wavefront modulation of electromagnetic incoming waves by plasmons is achieved by adjusting the relative permittivity e of the plasmonsrThe plasma frequency omega is controlled through electric regulationpTo realize the relative dielectric constant epsilon of the plasmarAnd (4) adjusting.
3. A plasmon modulator for object resolution of electromagnetic signals according to claim 1 wherein said physical confinement structure body of said modulator is made of quartz or plastic.
4. A plasmon modulator for object resolution of electromagnetic signals according to claim 1 wherein said modulator physical confinement structure body has a cross-sectional shape that is continuously curvilinear and has the shape of a convex structure.
5. A plasmon modulator for object resolution of electromagnetic signals according to claim 1 wherein said modulator physical confinement structure body has a cross-sectional minimum diameter of 2 to 3 times the aperture of the receiving antenna.
6. A plasma modulator for object resolution of electromagnetic signals as claimed in claim 1, wherein said fill gas is a noble gas.
7. A plasmon modulator for object resolution of electromagnetic signals according to claim 1 and wherein said modulator excitation structure comprises a coupling structure, an impedance matching structure and a feed structure connected in series, said coupling structure being connected outside said modulator physical confinement structure body.
8. The plasma modulator according to claim 7, wherein the coupling structure comprises a copper material wrapped outside the physical constraint structure body of the modulator, the impedance matching structure comprises a serial element and a parallel element, the feeding structure is a coaxial line, the copper material, the serial element and the coaxial line are sequentially connected in series, and the parallel element is connected in parallel with the coaxial line.
9. A vector microsensor employing a plasma modulator for object resolution of electromagnetic signals according to claim 1, comprising a receiving system and said plasma modulator,
the plasma modulator is positioned in front of the receiving system, and the cross section area of a physical constraint structure body of the modulator in the plasma modulator covers the antenna main lobe angle of the receiving system;
the weak correlation state number of the plasma modulator is larger than or equal to the division number of the target in the area to be measured, the state number refers to the same target unit, the difference of the amplitude and the phase of the signal received by the receiving antenna when the power of the excitation source is different is more than one order of magnitude of distinguishable precision of the receiving system, and the number of the state number depends on the power range of the excitation source, the physical parameters of the plasma, the shaping structure of the physical constraint structure main body of the modulator, the measurement precision of the receiving system and the background noise of an application scene.
10. The vector microsensor of claim 9, wherein the receiving system is a single antenna or multiple antennas, and when the receiving system is multiple antennas, each antenna is provided with one plasma modulator, and the excitation of each plasma modulator is in phase.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110571124.5A CN113314852A (en) | 2021-05-25 | 2021-05-25 | Plasma modulator and electromagnetic wave vector microscopic sensor |
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