Method for manufacturing transmission adjustable waveguide by utilizing metal back plate and dielectric cavity
Technical Field
The invention relates to the technical field of microwaves, in particular to a method for manufacturing a transmission adjustable waveguide by utilizing a metal back plate and a dielectric cavity.
Background
Zero refractive index materials are the focus of recent electromagnetic and physical research. Such materials have many unique electromagnetic properties, such as high gain, tunneling, wavefront tailoring, etc., due to their near-zero refractive index. In addition to the above properties, the zero refractive index material also has a photon doping effect. In particular, photonic doping is similar to the concept of semiconductor doping, meaning that a designed dielectric block is placed as a dopant in a zero index material, and the macroscopic properties of the zero index material are significantly affected, altered by the field distribution inside the dopant. However, the dopants of zero index materials are typically fixed in size and do not have the ability to be tuned; on the other hand, how to realize three-dimensional zero-refractive-index materials is also a big difficulty at present. Based on this, research on tunable cavity doping in rectangular waveguides has been carried out. The rectangular waveguide can enable the wavelength of electromagnetic waves in the propagation direction to be close to infinity by working at a cut-off frequency, meanwhile, the designed TE10 mode enables the wavelength of the waves in the height direction of the waveguide to also tend to infinity, therefore, in a XoY two-dimensional plane, the waveguide is equivalent to a two-dimensional isotropic near-zero dielectric constant material, the rectangular waveguide has a photon doping condition, an adjustable doping cavity is designed on the basis, the distribution of the field in the cavity is changed by the movement of a metal plate in the cavity, the cavity is integrally equivalent to a doping dielectric medium with variable properties, and the transmission characteristic of the waveguide is adjusted along with the movement of the metal plate.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a method for manufacturing a transmission adjustable waveguide by utilizing a metal back plate and a dielectric cavity.
In order to achieve the above purpose, the technical solution for solving the technical problem is as follows:
a method of fabricating a transmissively tunable waveguide using a metal backplate and a dielectric cavity, comprising the steps of:
step 1: selecting a cutoff frequency f and a transmission mode of rectangular waveguide operation;
step 2: determining the overall structure size of the waveguide and the dielectric filled in the waveguide port;
and step 3: determining the dielectric constant and magnetic permeability of a doped medium embedded in the waveguide and the overall size of the medium according to a photon doping theory;
and 4, step 4: determining that the doped medium embedded in the waveguide and connected with the waveguide can enable the transmission coefficient of the waveguide to be close to 1 by simulating the scattering parameters of the waveguide through full-wave simulation software;
and 5: determining the dielectric constant and the magnetic permeability of an adjustable doping cavity embedded in the waveguide, wherein the adjustable doping cavity consists of a dielectric block and a metal plate embedded in the dielectric block, the overall size of the cavity is determined by deducing the electromagnetic field mode of the metal plate in the cavity coupled with the dielectric block and the relation of wave number components in x, y and z directions, and the size of the metal plate in the cavity is determined;
step 6: the transmission characteristic of the movable metal plate for adjusting the waveguide is simulated through full-wave simulation software, the movable metal plate can change the waveguide from full transmission to total reflection, the equivalent permeability of the waveguide in the moving process of the metal plate is calculated through an equivalent parameter extraction algorithm, and an extracted permeability curve is magnetic resonance.
Further, in step 1, the operating frequency of the waveguide is in the microwave band, and the waveguide transmission mode is the TE10 mode, and the operating frequency is the cut-off frequency of the TE10 mode.
Further, in step 2, the waveguide overall structure comprises the geometric parameters and the metal material of the metal structures of the incident port, the transmission part and the exit port, and the dielectric material filled in the incident port and the exit port.
Furthermore, the metal material is copper or aluminum, the filled dielectric medium is a non-magnetic microwave material, the dielectric constant is 2-10, and the magnetic permeability is 1.
Further, in step 3, the photon doping theory is an equivalent permeability formula when the transverse magnetic wave is incident on the near-zero dielectric constant material:
wherein, mueffIs the equivalent permeability, mu, of the doped near-zero dielectric constant materialrIs the relative permeability, mu, of a near-zero dielectric constant material0Is the permeability of free space, S is the total cross-sectional area of the material with near-zero dielectric constant, Sd,n(N is from 1 to N) is the cross-sectional area of each impurity doped in the near-zero dielectric constant material, H0Is the magnetic field value in the material with near-zero dielectric constant, the integral multiple Ed,nDl is the integral of the loop tangential electric field along the boundary of the impurity.
Further, in step 3, the doped medium is a non-magnetic microwave material, the dielectric constant is 20-50, and the magnetic permeability is 1.
Further, in step 4, the full-wave simulation software adopts COMSOL software.
Further, in step 5, the size of the tunable doping cavity is determined by the relation of x, y, and z wavenumbers, where the relation is:
wherein λ isgIs the wavelength in the waveguide.
Further, in step 6, the moving metal plate moves back and forth along the propagation direction of the TE wave in the tunable cavity from one end of the cavity to the other end.
Further, in step 6, the magnetic resonance refers to that the magnetic permeability is within a certain position interval, the magnetic permeability will change from a negative maximum value to a positive maximum value or from a positive maximum value to a negative maximum value, and a zero-crossing point is arranged in the middle of a certain interval.
Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages and positive effects:
1. the rectangular waveguide utilizes the adjustable doped medium cavity, and has the advantage of adjustable transmission characteristic;
2. the rectangular waveguide works at cut-off frequency and has the property of a zero-refractive-index material, and the manufactured curved waveguide and the discontinuous waveguide still have an adjustable function;
3. the rectangular waveguide can realize the matching between two ports filled with different media by adjusting the position of the metal plate.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:
FIG. 1 is a schematic diagram of the overall structure of a waveguide operating at 5.8GHz according to a method for manufacturing a tunable transmission waveguide using a metal backplate and a dielectric cavity of the present invention;
FIG. 2 is a transmission diagram of the internal structure of a waveguide operating at 5.8GHz according to a method for fabricating a transmission tunable waveguide using a metal backplate and a dielectric cavity of the present invention;
FIG. 3 is a front view of a waveguide operating at 5.8GHz according to a method for fabricating a tunable transmission waveguide using a metal backplane and a dielectric cavity of the present invention;
FIG. 4 is a side view of a waveguide operating at 5.8GHz according to a method of the invention for fabricating a tunable transmission waveguide using a metal backplane and a dielectric cavity;
FIG. 5 is a top view of a waveguide operating at 5.8GHz according to a method of the present invention for fabricating a tunable transmission waveguide using a metal backplane and a dielectric cavity;
FIG. 6 is a simulation plot of the waveguide transmittance near 1 after doping with a medium when the method of the present invention for fabricating a transmittance tunable waveguide using a metal backplate and a dielectric cavity operates at 5.8 GHz;
FIG. 7 is a spatial amplitude distribution plot of the y-direction electric field component of a waveguide after doping with a dielectric when a method of the present invention for fabricating a transmission tunable waveguide using a metal backplate and a dielectric cavity operates at 5.8 GHz;
FIG. 8 is a schematic diagram of a tunable doped cavity in a waveguide operating at 5.8GHz according to a method of the invention for fabricating a transmission tunable waveguide using a metal backplate and a dielectric cavity;
FIG. 9 is a schematic diagram of Matlab components of the magnetic field in the tunable doped cavity in the waveguide when the method for manufacturing the transmittance tunable waveguide by using the metal back plate and the dielectric cavity works at 5.8GHz according to the invention;
FIG. 10 is a COMSOL simulation diagram of the components of the magnetic field in the tunable doped cavity in the waveguide when the method of the present invention for fabricating a transmittance tunable waveguide using a metal backplate and a dielectric cavity operates at 5.8 GHz;
FIG. 11 is a simulation diagram of the total transmission of the waveguide operating at 5.8GHz according to the method of the present invention for fabricating a tunable transmission waveguide using a metal backplate and a dielectric cavity;
FIG. 12 is a graph of the spatial amplitude distribution of the y-direction electric field component at full waveguide transmission for a method of the present invention for fabricating a tunable transmission waveguide using a metal backplate and a dielectric cavity at 5.8 GHz;
FIG. 13 is a simulation diagram of total reflection of the waveguide operating at 5.8GHz according to a method of the present invention for fabricating a tunable transmission waveguide using a metal backplate and a dielectric cavity;
FIG. 14 is a spatial amplitude distribution diagram of the y-direction electric field component when the waveguide is totally reflected at 5.8GHz according to the method for manufacturing the transmittance tunable waveguide using the metal back plate and the dielectric cavity of the present invention;
FIG. 15 shows the scattering parameters S11 at the corresponding position when the metal plate moves in the x direction in the tunable doped cavity when the method of the present invention for making a tunable transmission waveguide using a metal backplate and a dielectric cavity operates at 5.8 GHz;
FIG. 16 shows the scattering parameters S21 at the corresponding position when the metal plate moves in the x direction in the tunable doped cavity when the method of the present invention for making a tunable waveguide with transmittance using a metal back plate and a dielectric cavity operates at 5.8 GHz;
FIG. 17 shows equivalent permeability extracted from S11 and S21 parameters when the method for fabricating a tunable transmission waveguide using a metal backplate and a dielectric cavity according to the present invention operates at 5.8 GHz.
Detailed Description
While the embodiments of the present invention will be described and illustrated in detail with reference to the accompanying drawings, it is to be understood that the invention is not limited to the specific embodiments disclosed, but is intended to cover various modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.
The embodiment discloses a method for manufacturing a transmission adjustable waveguide by utilizing a metal back plate and a dielectric cavity, which comprises the following steps:
step 1: selecting a cut-off frequency I and a transmission mode of the rectangular waveguide;
step 2: determining the overall structure size of the waveguide and the dielectric filled in the waveguide port;
and step 3: determining the dielectric constant and magnetic permeability of a doped medium embedded in the waveguide and the overall size of the medium according to a photon doping theory;
and 4, step 4: determining that the doped medium embedded in the waveguide and connected with the waveguide can enable the transmission coefficient of the waveguide to be close to 1 by simulating the scattering parameters of the waveguide through full-wave simulation software;
and 5: determining the dielectric constant and the magnetic permeability of an adjustable doping cavity embedded in the waveguide, wherein the adjustable doping cavity consists of a dielectric block and a metal plate embedded in the dielectric block, the overall size of the cavity is determined by deducing the electromagnetic field mode of the metal plate in the cavity coupled with the dielectric block and the relation of wave number components in x, y and z directions, and the size of the metal plate in the cavity is determined;
step 6: the transmission characteristic of the waveguide is adjusted by simulating the moving metal plate through full-wave simulation software, the moving metal plate can change the waveguide from full transmission (the transmission coefficient is close to 1) to total reflection (the transmission coefficient is close to 0), the equivalent permeability of the waveguide in the moving process of the metal plate is calculated through an equivalent parameter extraction algorithm, and the extracted permeability curve is a magnetic resonance.
Further, in step 1, the operating frequency of the waveguide is in the microwave band, and the waveguide transmission mode is the TE10 mode, and the operating frequency is the cut-off frequency of the TE10 mode.
Further, in step 2, the waveguide overall structure comprises the geometric parameters and the metal material of the metal structures of the incident port, the transmission part and the exit port, and the dielectric material filled in the incident port and the exit port. The geometrical parameters of the doped medium comprise the length, the width and the thickness of the medium, the width of the medium is the same as that of the waveguide, and the length and the thickness of the medium are determined by optimizing the transmission coefficient (approaching 1) of the waveguide.
Preferably, the metal material is copper or aluminum, the filled dielectric medium is a non-magnetic microwave material, the dielectric constant is 2-10, and the magnetic permeability is 1.
Further, in step 3, the photon doping theory is an equivalent permeability formula when a transverse magnetic wave (TM wave) is incident on the near-zero dielectric constant material:
wherein, mueffIs the equivalent permeability, mu, of the doped near-zero dielectric constant materialrIs the relative permeability, mu, of a near-zero dielectric constant material0Is the permeability of free space, S is the total cross-sectional area of the material with near-zero dielectric constant, Sd,n(N is from 1 to N) is the cross-sectional area of each impurity doped in the near-zero dielectric constant material, H0Is the magnetic field value in the material with near-zero dielectric constant, the integral multiple Ed,nDl is the integral of the loop tangential electric field along the boundary of the impurity.
Preferably, in step 3, the doping medium is a non-magnetic microwave material, the dielectric constant is 20-50, and the magnetic permeability is 1.
Preferably, in step 4, the full-wave simulation software adopts COMSOL software.
Further, in step 5, the size of the tunable doping cavity is determined by the relation of x, y, and z wavenumbers, where the relation is:
wherein λ isgIs the wavelength in the waveguide.
Further, in step 6, the moving metal plate moves back and forth along the TE wave propagation direction (x direction) in the tunable cavity from one end of the cavity to the other end.
Further, in step 6, the magnetic resonance refers to that the magnetic permeability is within a certain position interval, the magnetic permeability will change from a negative maximum value to a positive maximum value or from a positive maximum value to a negative maximum value, and a zero-crossing point is arranged in the middle of a certain interval.
The method comprises the following specific implementation steps:
(1) the operating frequency f of the rectangular waveguide is chosen to be 5.8 GHZ.
(2) The overall waveguide structure dimensions and the dielectric medium that the waveguide ports are filled with are determined. As shown in fig. 1-5, the present embodiment includes a width (z direction) of c/2f 25.8mm, where c is the speed of light in vacuum, a height (y direction) of 10mm, a length (x direction) of the entrance port and the exit port of 103.2mm, a length (x direction) of the transmission part of 80mm, a thickness of the waveguide itself of 5mm, and a material filled in the entrance port and the exit port of RT duroid 6002 using copper metal.
(3) The doped medium embedded in the waveguide was dimensioned to be 25.8mm wide, 4.8mm high, 12mm long and the material was a microwave dielectric ceramic with a dielectric constant of 37.
(4) As shown in fig. 6 and 7, the transmission coefficient of the doped medium embedded in the waveguide was determined to be close to 1.
(5) FIG. 8 shows a tunable doped cavity structure of the present invention with a width d along the z-direction325.8mm, length d in x-direction125.8mm, height d in y-direction28.722 mm. The metal plate is 25.8mm at x, the width and height of the metal plate are the same as those of the doped cavity, the thickness of the metal plate is 1.032mm, the metal plate can only move along the x direction, and the moving range does not exceed the cavity (0-d)1). The cavity is filled with Rogers3010 material, and the metal plate material is copper.
(6) As shown in fig. 9 and 10, which are Matlab and software simulation comparison graphs of each magnetic field component in the tunable doped cavity, the electromagnetic field in the cavity is derived by using the waveguide equation as follows:
wherein each wavenumber component is:
and the wave number relationship satisfies
(7) As shown in fig. 11-14, are electromagnetic software simulations of moving the metal plate in the cavity so that the waveguide changes from fully transmissive to fully reflective. As shown in fig. 15 to 17, S-parameters extracted during the movement of the metal plate and the calculated equivalent permeability are shown.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.