CN110112514A - Method for inhibiting non-rotational symmetry mode in coaxial slow-wave high-power microwave source - Google Patents
Method for inhibiting non-rotational symmetry mode in coaxial slow-wave high-power microwave source Download PDFInfo
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- CN110112514A CN110112514A CN201910398065.9A CN201910398065A CN110112514A CN 110112514 A CN110112514 A CN 110112514A CN 201910398065 A CN201910398065 A CN 201910398065A CN 110112514 A CN110112514 A CN 110112514A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
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Abstract
The invention disclosesA method for suppressing non-rotational symmetric modes in a coaxial slow wave high-power microwave source aims to provide a method for suppressing all non-rotational symmetric modes in the coaxial slow wave high-power microwave source. The technical scheme is that firstly, selected slow wave structure parameters including the number N of periods, the period length L, the shape of a slow wave structure and the ripple depth h are determined, the distance D between an inner conductor and an outer conductor of a coaxial slow wave high-power microwave source is determined, the coaxial slow wave high-power microwave source capable of inhibiting a non-rotational symmetry mode is designed, the coaxial slow wave high-power microwave source can enable an electron beam to be synchronously interacted and transduced with a quasi-pi mode of a quasi-TEM mode, and TM is utilized to carry out energy conversion01The coupling of the (N-3)/Npi modes of the mode suppresses the non-rotationally symmetric mode. The invention can inhibit the excitation of a non-rotational symmetric mode in a coaxial slow-wave high-power microwave source and ensure the effective oscillation starting of a rotational symmetric quasi-TEM mode.
Description
Technical field
The invention belongs to High-Power Microwave technical fields, are related to the mode control method of high-power microwave source, especially one
Kind is for high band, the suppressing method greater than mould than non-rotational symmetry mode in coaxial slow wave high-power microwave source.
Background technique
High-Power Microwave typically refers to frequency 1GHz to 100GHz, and pulse peak power is greater than 100MW, frequency in microwave wave
The electromagnetic wave of section.Since it has the characteristics that very high-peak power, have in fields such as directed energy weapon, High power radars non-
Often important application prospect, and the extensive concern and numerous studies investment of many countries have been obtained in recent years, it achieves greatly
Technological progress.With the expansion of High-Power Microwave technical applications, develop into High-Power Microwave skill to higher frequency section
One important developing direction of art.
High-power microwave source is the core devices for generating High-Power Microwave.In various high-power microwave sources, slow wave Gao Gong
Rate microwave source due to have the advantages that high power, high efficiency, Gao Zhongying output and by attention.Traditional slow wave High-Power Microwave
Source uses single mode hollow structure, contains only TM in power output waveguide01Mode and to TM02Mode cutoff, i.e. power output wave
The radius R led0With the relationship for generating microwave wavelength λ are as follows: 0.38 λ < R0< 0.88 λ causes hollow structure in high band application difficult.
Therefore, for the needs to high-frequency, high power capacity, novel slow wave high-power microwave sources some in recent years are used greater than mould ratio
Coaxial configuration, keep internal-and external diameter spacing it is constant in the case where, uniform zoom increase device radial dimension.At this point, electronics
Beam and slow-wave structure surface distance increase, and electromagnetic field reduces in conductive surface field strength, can significantly alleviate fuel factor, improve power
Capacity.
Coaxial high-power microwave source is generally operational in the quasi- π mould of Quasi-TEM mode, generally selects biggish radial dimension, wave
Lead that interior existing model number is more, therefore scheme control becomes the emphasis of coaxial Slow Wave high-power microwave source research and difficult
Point.Scheme control is complex in such devices, two aspects is broadly divided into, first is that the TM of rotational symmetry0nThe suppression of mode
System, this mode have round symmetry characteristic identical with Quasi-TEM mode, easily change with the interaction of the electron beam of same rotational symmetry
Energy；Second is that non-rotationally-symmetric quasi- TEv1Mode (is referred to as EH in some documentsv1Mode) inhibition, although this mode is not
Has the characteristic of rotational symmetry, but it and Quasi-TEM mode have similar Characteristic of Surface Wave, are distributed in slow-wave structure surface
Axial electric field can also interact with electron beam.
Currently, coaxial Slow Wave microwave source is directed to TM0nThe suppressing method relative maturity of mode generally utilizes operating mode
The Characteristic of Surface Wave of (Quasi-TEM mode), by electron-beam position design in the position close to slow-wave structure surface, to make electron beam
The high-order TM for avoiding and volume wave property being presented0nMode interaction.But this suppressing method is not particularly suited for being all surface wave
The quasi- TE of non-rotational symmetryv1Mode.[Siyao Chen, Jun were once pointed out in the distant equal research report of National University of Defense technology Chen Si
Zhang, Jiande Zhang.Excitation and suppression of asymmetrical modes in high
Frequency coaxial slow wave structures.Journal of Applied Physics, 2019,
Vol.125, No.023302 (Chen Siyao, Zhang Jun, Zhang Jiande, the excitation and suppression of high frequency coaxial slow-wave structure non-rotational symmetry mode
System, applicating physical magazine, 2019 volume 125, page 023302)]: in single hop coaxial slow wave structure, the quasi- TE of non-rotational symmetryv1
Mode, thus always can be by preferential excitation since higher than Quasi-TEM mode growth rate, starting oscillation current is low.Its structure as shown in Figure 1,
It is made of cathode 1, anode 2, slow-wave structure 3, outer conductor 4, inner conductor 5.Parasitic mode of the non-rotational symmetry mode as device, is to set
The mode that must be avoided in meter, if in coaxial slow wave high-power microwave source there are non-rotational symmetry mode if can seriously affect it is coaxial
The efficiency and stability of slow wave high-power microwave source.Therefore, it is necessary to study the suppressions of non-rotational symmetry mode in coaxial microwave source
Method processed.
Currently, had not been reported to the suppressing method of non-rotational symmetry mode in coaxial high-power microwave source, this be mainly because
Mode overlapping between non-rotational symmetry mode is extremely serious, and high frequency characteristics is similar not to be easily distinguishable.For non-rotational symmetry
Mode suppression problem, which has, inspires meaning, crosses mode structure [Zhen Bai, Jun Zhang, Huihuang using coaxial
Zhong.A dual-mode operation overmoded coaxial millimeter-wave generator with
high power capacity and pure transverse electric and magnetic mode
(Bai Zhen, Zhang Jun, Zhong Huihuang, a kind of high power are pure by output.Physics of Plasmas, 2016, Vol.23, No.043109
TEM mould output dual-mode of operation cross the coaxial millimeter baud generator plasma physics of mould, 2016 volume 23,043109
Page)] coaxial slow wave high-power microwave source can be enabled to export symmetrical mixed mode.However, for how to pass through mould slow wave knot
The design of structure effectively inhibits non-rotational symmetry mode, which is not directed to.
In conclusion can be by the quasi- TE of non-rotational symmetry in coaxial slow wave high-power microwave sourcev1Mode effectively inhibits, and enables rotation
Turn symmetrical quasi- TEM or TM01The method that mode effectively works has significant application value, but has not yet to see open source literature and be related to this
Aspect content.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of suppressing methods of non-rotational symmetry mode, effectively inhibit coaxial
All non-rotational symmetry modes in slow wave high-power microwave source, enable Quasi-TEM mode effectively work.
Core of the invention thought is electron beam interaction transducing synchronous with the quasi- π mould of Quasi-TEM mode, utilizes TM01Mode
(N-3)/N π mould coupling inhibit non-rotational symmetry mode.
Technical solution of the present invention the following steps are included:
The first step, it is suitable slow according to the working frequency ω of coaxial slow wave high-power microwave source and electron-beam voltage U selection
Wave structure parameter.Specific step is as follows:
1.1. the suitable number of cycles N of slow-wave structure is determined；
Firstly, calculating in coaxial slow wave high-power microwave source, the quasi- π mould and TM of Quasi-TEM mode01(N-3)/N π mould of mode
The maximum cycle number N that can be coupledmax, the electron beam needs satisfaction condition synchronous with Quasi-TEM mode:
Wherein: ω is coaxial high-power microwave source working frequency, vbFor coaxial high-power microwave source electron beam velocity, L is
The cycle length of slow-wave structure, N are the number of cycles of slow-wave structure.In addition, TM01(N-3)/N π mould of mode needs to meet and standard
The coupling condition of TEM mode, i.e. working frequency are identical, at this time TM01(N-3)/N π mould of mode need to be above light beam line, thus
Have:
Wherein: c is the light velocity.Above-mentioned two equations simultaneousness can be solved:
Wherein:It is normalization velocity of electrons, the unit of voltage U is kV.It is thus available
Maximum number of cycles is no more than
Further according to maximum cycle number NmaxDetermine the suitable period of the slow-wave structure of coaxial slow wave high-power microwave source
Number.The value of number of cycles cannot get NmaxValue, this is because on the one hand when number of cycles N is close to NmaxWhen, TM01Mode
(N-3)/N π mould very close to light beam line, the internal and external conductor space D that will lead to coaxial waveguide it is excessive and to TM02Mode is not ended；
Another when number of cycles is excessive, vertical pattern degree of separation is low face to face, longitudinal mode modeling relative difficulty.Thus selected in actual design
The number of cycles selected should compare NmaxIt is smaller, need designer rule of thumb to choose, in general number of cycles N ratio NmaxIt is small by 2
It is more appropriate to 3；
1.2. the cycle length L of slow-wave structure is determined according to electron-beam voltage U and number of cycles N；
Electron beam needs to meet the condition synchronous with Quasi-TEM mode:To obtain the meter of cycle length L
Calculation method:
1.3. the shape and ripple's depth h of slow-wave structure are determined, method is:
1.3.1 the shape of slow-wave structure is determined to efficiency, the demand of power according to high-power microwave source: pursues high efficiency
When choose rectangle ripple, choose cosine or triangle ripple when pursuing high power, if desired the optimum balance of efficiency and power, select
Trapezoidal ripple.
1.3.2 solution dispersion equation is calculated using numerical value or utilize HFSS (High Frequency Structure
Simulator) exist with electromagnetic simulation softwares, acquisition ripple's depths such as CST (Computer Simulation Technology)
The dispersion curve of coaxial slow wave structure when different values is found when Quasi-TEM mode (N-1)/N π mould feature in dispersion curve
Ripple's depth when frequency is ω, this ripple's depth is taking for the ripple's depth h of slow-wave structure in coaxial high-power microwave source
Value；
Second step determines that the inside and outside of coaxial slow wave high-power microwave source is led according to the slow-wave structure parameter that the first step determines
Body space D makes the quasi- π mould and TM of Quasi-TEM mode01(N-3)/N π mould close-coupled of mode, it is non-rotating right that design is able to suppress
The coaxial slow wave high-power microwave source of title mode.Specific method is:
2.1 build coaxial slow wave high-power microwave source interaction region structural model using electromagnetic simulation software HFSS or CST,
Slow-wave structure both ends are connected with smooth waveguide, slow-wave structure number of cycles N, cycle length L and the wave determined using step before
Line depth h builds model and is emulated, and solves transmission curve；By constantly changing internal and external conductor space D, observe on transmission curve
(the N-1)/N π mould and TM of Quasi-TEM mode01The characteristic frequency point of (N-3)/N π mould of mode, when two pattern feature frequency points are completely heavy
D value when conjunction be the present invention claims internal and external conductor space D；
The slow-wave structure number of cycles of coaxial slow wave high-power microwave source is set N by 2.2, and cycle length is set as L, wave
Line depth is set as h, sets D for internal and external conductor spacing, obtains the coaxial slow wave Gao Gong for being able to suppress non-rotational symmetry mode
Rate microwave source.
Third step inhibits non-rotational symmetry mode using the coaxial slow wave high-power microwave source that second step designs,
Method is as follows:
3.1. initial stage is vibrated in coaxial slow wave high-power microwave source, enters coaxial slow wave Gao Gong from the electron beam of emission of cathode
The slow-wave structure region of rate microwave source, transfers energy to the synchronous mode in microwave source, the Quasi-TEM mode including rotational symmetry
With non-rotationally-symmetric quasi- TEv1Mode, thus a small amount of generation Quasi-TEM mode and quasi- TEv1Mode.
3.2. to be partially converted into Quasi-TEM mode non-for the noncoherent boundary of slow-wave structure in coaxial slow wave high-power microwave source
Synchronous TM01Mode makes quasi- TEv1Mode is partially converted into asynchronous TMv1Mode.
3.3. in coaxial slow wave high-power microwave source, asynchronous TM01Mode and asynchronous TMv1Mode and electron beam
Interaction transducing effect often uses electronic conductance GeCharacterization.When (Quasi-TEM mode of rotational symmetry is non-rotationally-symmetric for synchronous mode
Quasi- TEv1Mode) (N-1)/N π mould and the Asynchronous Mode (TM of rotational symmetry01Mode or non-rotationally-symmetric TMv1Mode)
When m/N π mode coupling, m is longitudinal π modulus of Asynchronous Mode, electronic conductance GeMeet:
Ge=-2m2(N-1)2π-2G0[(N-1)2-m2]-3[cos(mπ)cos((N-1)π)-1]
Wherein, G0It is DC electronic conductance, it is only related to electron beam parameter.Using the coaxial of the above parameter (N, h, D)
In slow wave high-power microwave source, TM01The m of mode, which is equal to N-3, leads to electronics due to cos ((N-3) π) cos ((N-1) π)=1
Conductance Ge=0, therefore TM01For mode not with electron beam transducing, microwave source will not inhibit the Quasi-TEM mode of rotational symmetry；Rather than it revolves
Turn symmetrical TMv1The m of mode deviates N-3 (being not equal to N-3), electronic conductance Ge> 0, slow-wave structure is by asynchronous TMv1Mode
Energy transmission electron beam, due to TMv1The energy of mode is from quasi- TEv1It is transformed in mode, thus it is non-rotationally-symmetric
Quasi- TEv1The gross energy of mode reduces.Initial stage, Quasi-TEM mode and quasi- TE are vibrated in microwave sourcev1The energy difference of mode is little, with
Quasi- TEv1The gross energy of mode reduces, and the accounting of the Quasi-TEM mode of rotational symmetry increases, and gradually occupies leading position.With standard
The accounting of TEM mode increases, and the energy that electron beam passes to Quasi-TEM mode further increases, and passes to non-rotationally-symmetric standard
TEv1The energy of mode further decreases, therefore before microwave saturation, non-rotational symmetry mode can be totally constrained.
Following technical effect can achieve using the present invention: inhibiting non-rotational symmetry in coaxial slow wave high-power microwave source
The excitation of mode guarantees the effective starting of oscillation of the Quasi-TEM mode of rotational symmetry.
Detailed description of the invention
Fig. 1 is a kind of structure of the coaxial slow wave high-power microwave source of the trapezoidal ripple of single hop outer conductor described in background technique
Schematic diagram；
Fig. 2 is overview flow chart of the present invention；
Fig. 3 is the signal period slow-wave structure structural schematic diagram using the first step of the present invention design；
Fig. 4 is transfer curve when second step of the present invention uses coaxial trapezoidal outer ripple；
Fig. 5 is the field distribution schematic diagram of coaxial slow wave high-power microwave source operating mode described in background technique；
Fig. 6 is the field distribution signal of coaxial trapezoidal slow wave high-power microwave source operating mode designed according to this invention
Figure.
Specific embodiment
Fig. 1 is background technique [Siyao Chen, Jun Zhang, Jiande Zhang.Excitation and
suppression of asymmetrical modes in high frequency coaxial slow wave
Structures.Journal of Applied Physics, 2019, Vol.125, No.023302 (Chen Siyao, Zhang Jun, Zhang Jian
Moral, the excitation and inhibition of high frequency coaxial slow-wave structure non-rotational symmetry mode, applicating physical magazine, 2019 volume 125,
Page 023302)] in the coaxial slow wave high-power microwave source of single hop structural schematic diagram, including cathode 1, anode 2 and slow wave knot
Structure 3, outer conductor 4, inner conductor 5.In this configuration, non-rotationally-symmetric quasi- TEv1Mode is difficult to be suppressed, always prior to standard
TEM mode starting of oscillation.
Fig. 2 is overview flow chart of the present invention；The present invention the following steps are included:
The first step, it is suitable slow according to the working frequency ω of coaxial slow wave high-power microwave source and electron-beam voltage U selection
Wave structure parameter.Specific step is as follows:
1.1 determine that the suitable number of cycles N:N of slow-wave structure is smaller by 2 to 3 than maximum cycle number Nmax, It is normalization velocity of electrons, the unit of electron-beam voltage U is kV.
1.2. the cycle length L of slow-wave structure is determined according to electron-beam voltage U and number of cycles N；
1.3. the shape and ripple's depth h of slow-wave structure are determined, method is:
1.3.1 the shape of slow-wave structure is determined to efficiency, the demand of power according to high-power microwave source: pursues high efficiency
When choose rectangle ripple, choose cosine or triangle ripple when pursuing high power, if desired the optimum balance of efficiency and power, Chang Xuan
With trapezoidal ripple；
1.3.2 it is calculated using numerical value and solves dispersion equation or utilize the electromagnetic simulation softwares such as HFSS and CST, obtain ripple
The dispersion curve of coaxial slow wave structure of the depth in different values is found when Quasi-TEM mode (N-1)/N π mould in dispersion curve
Characteristic frequency be ω when ripple's depth, this ripple's depth is the ripple's depth of slow-wave structure in coaxial high-power microwave source
The value of h；
Second step determines that the inside and outside of coaxial slow wave high-power microwave source is led according to the slow-wave structure parameter that the first step determines
Body space D makes the quasi- π mould and TM of Quasi-TEM mode01(N-3)/N π mould close-coupled of mode, it is non-rotating right that design is able to suppress
The coaxial slow wave high-power microwave source of title mode.Specific method is:
2.1 build coaxial slow wave high-power microwave source interaction region structural model using electromagnetic simulation software HFSS or CST,
Slow-wave structure both ends are connected with smooth waveguide, build model using slow-wave structure number of cycles N, cycle length L and ripple's depth h
It is emulated, solves transmission curve；By constantly changing internal and external conductor space D, (the N- of Quasi-TEM mode on transmission curve is observed
1)/N π mould and TM01The characteristic frequency point of (N-3)/N π mould of mode, the D value when two pattern feature frequency points are completely coincident is i.e.
For the present invention claims internal and external conductor space D；
The slow-wave structure number of cycles of coaxial slow wave high-power microwave source is set N by 2.2, and cycle length is set as L, wave
Line depth is set as h, sets D for internal and external conductor spacing, obtains the coaxial slow wave Gao Gong for being able to suppress non-rotational symmetry mode
Rate microwave source.
Third step inhibits non-rotational symmetry mode using the coaxial slow wave high-power microwave source that second step designs,
Process is as follows:
3.1. initial stage is vibrated in microwave source, the electron beam emitted from cathode 1 enters the slow of coaxial slow wave high-power microwave source
Wave structure region, energy transmission to the synchronous mode in microwave source, Quasi-TEM mode and non-rotational symmetry including rotational symmetry
Quasi- TEv1Mode, thus Quasi-TEM mode and quasi- TEv1Mode generates on a small quantity；
3.2. the noncoherent boundary of slow-wave structure 2 is partially converted into Quasi-TEM mode in coaxial slow wave high-power microwave source
Asynchronous TM01Mode makes quasi- TEv1Mode is partially converted into asynchronous TMv1Mode；
3.3. in the coaxial slow wave high-power microwave source using the above parameter (N, h, D), asynchronous TM01Mode with
TMv1Mode and the interaction transducing effect of electron beam often use electronic conductance GeCharacterization.As synchronous mode (the quasi- TEM of rotational symmetry
Mode or non-rotationally-symmetric quasi- TEv1Mode) (N-1)/N π mould and the Asynchronous Mode (TM of rotational symmetry01Mode or non-rotation
Turn symmetrical TMv1Mode) m/N π mode coupling when, m be Asynchronous Mode longitudinal π modulus, electronic conductance GeMeet:
Ge=-2m2(N-1)2π-2G0[(N-1)2-m2]-3[cos(mπ)cos((N-1)π)-1]
Wherein, G0It is DC electronic conductance, it is only related to electron beam parameter.Using the coaxial of the above parameter (N, h, D)
In slow wave high-power microwave source, TM01The m of mode, which is equal to N-3, leads to electronics due to cos ((N-3) π) cos ((N-1) π)=1
Conductance Ge=0, TM01For mode not with electron beam transducing, microwave source will not inhibit the Quasi-TEM mode of rotational symmetry；Non-rotational symmetry
TMv1The m of mode deviates N-3, electronic conductance Ge> 0, slow-wave structure is by asynchronous TMv1The energy transmission electron beam of mode,
Due to TMv1The energy of mode is from quasi- TEv1It is transformed in mode, thus non-rotationally-symmetric quasi- TEv1The gross energy of mode drops
It is low.Initial stage, Quasi-TEM mode and quasi- TE are vibrated in microwave sourcev1The energy difference of mode is little, with quasi- TEv1The gross energy of mode
Reduce, the accounting of the Quasi-TEM mode of rotational symmetry increases, and gradually occupies leading position.As the accounting of Quasi-TEM mode increases,
The energy that electron beam passes to Quasi-TEM mode further increases, and passes to non-rotationally-symmetric quasi- TEv1The energy of mode is further
Reduce, therefore before microwave saturation, non-rotational symmetry mode can be totally constrained.
Fig. 3 is the structural schematic diagram using signal period (trapezoidal) slow-wave structure 2 of the first step of the present invention design.Wherein Ro
For the radius of outer conductor 4, Ri is the radius of inner conductor 5.When operating voltage is 350kV, the N that is calculated according to the first stepmax
< 11.2, the number of cycles empirically chosen is 9, and the cycle length L of selection is 1.9mm, the long side p2 wide 1.4mm of trapezoidal ripple,
Narrow side p1 wide 0.5mm, ripple's depth h are 0.9mm.
After the simulation model that second step of the present invention is established in HFSS according to the structural parameters in Fig. 3, internal and external conductor is adjusted
Space D, obtaining abscissa is the transfer curves that frequency, ordinate are transmission coefficient.When transfer curve meets Fig. 4's
When form, i.e. the 8/9 π mould and TM of Quasi-TEM mode016/9 π mould of mode has almost consistent biography near 56.8GHz frequency point
When defeated characteristic, close-coupled occurs for two modes, and modeling parameters internal and external conductor space D is 4.8mm in HFSS at this time.
Structure shown in Fig. 3 meets design requirement of the invention, can achieve effective inhibition to non-rotational symmetry mode, benefit
This kind in background technique coaxial slow wave microwave source is emulated with particle simulation software Chipic, the field distribution of operating mode is such as
Shown in Fig. 5, electric field angularly has 14 extreme values, and operating mode is non-rotationally-symmetric quasi- TE71Mode.Using the present invention the
One, the coaxial slow wave microwave source of two steps design is emulated in particle simulation software, the field distribution of operating mode such as Fig. 6 institute
Show, electric field is evenly distributed in angular, and microwave source incentive mode is Quasi-TEM mode, and non-rotational symmetry mode is effectively suppressed.
In order to easily illustrate method of the invention, specific implementation part of the invention uses coaxial trapezoidal in Fig. 3
Outer ripple struction illustrates the present invention to the reliability of non-rotational symmetry mode suppression.Trapezoidal is a kind of ripple most generallyd use
Structure, if P1=0, at triangle, if P1=P2, at rectangle.As long as therefore illustrating the design of trapezoidal parameter, ability
Field technique personnel know how to design other shapes of ripple.And the present invention relies primarily on the D of second step and third step is come pair
Non-rotational symmetry mode is inhibited, and effect of drawing up and the corrugated shape that the first step determines are not related, Mode Coupling principle
It is unrelated with corrugated shape.Therefore, including the other shapes of coaxial slow wave structure such as rectangular shape, triangle, this can be used
The thought of invention is designed, and reaches the inhibitory effect to non-rotational symmetry mode.
Claims (3)
1. the suppressing method of non-rotational symmetry mode in a kind of coaxial slow wave high-power microwave source, it is characterised in that including following step
It is rapid:
The first step selects suitable slow wave knot according to the working frequency ω of coaxial slow wave high-power microwave source and electron-beam voltage U
Structure parameter:
1.1 determine that the suitable number of cycles N:N of slow-wave structure is smaller by 2 to 3 than maximum cycle number Nmax, It is normalization velocity of electrons, the unit of electron-beam voltage U is kV；
1.2. the cycle length L of slow-wave structure is determined according to electron-beam voltage U and number of cycles N；
1.3. the shape and ripple's depth h of slow-wave structure are determined, method is:
1.3.1 the shape of slow-wave structure is determined to efficiency, the demand of power according to high-power microwave source；
1.3.2 it is calculated using numerical value and solves dispersion equation or electromagnetic simulation software, it is same in different values to obtain ripple's depth
The dispersion curve of axis slow-wave structure finds the wave when Quasi-TEM mode (N-1)/N π mould characteristic frequency is ω in dispersion curve
Line depth, this ripple's depth are the value of the ripple's depth parameter h of slow-wave structure in coaxial high-power microwave source；
Second step, according to the slow-wave structure parameter that the first step determines, between the internal and external conductor for determining coaxial slow wave high-power microwave source
Away from D, design is able to suppress the coaxial slow wave high-power microwave source of non-rotational symmetry mode, and specific method is:
2.1 build coaxial slow wave high-power microwave source interaction region structural model, slow-wave structure both ends using electromagnetic simulation software
It is connected with smooth waveguide, builds model using slow-wave structure number of cycles N, cycle length L and ripple's depth h and emulated, asked
Solve transmission curve；By constantly changing internal and external conductor space D, (the N-1)/N π mould and TM of Quasi-TEM mode on transmission curve are observed01
The characteristic frequency point of (N-3)/N π mould of mode, the D value when two pattern feature frequency points are completely coincident are between internal and external conductor
Away from D；
The slow-wave structure number of cycles of coaxial slow wave high-power microwave source is set N by 2.2, and cycle length is set as L, and ripple is deep
Degree is set as h, sets D for internal and external conductor spacing, the coaxial slow wave high power for obtaining being able to suppress non-rotational symmetry mode is micro-
Wave source；
Third step inhibits non-rotational symmetry mode using the coaxial slow wave high-power microwave source that second step designs, process
It is as follows:
3.1. initial stage is vibrated in coaxial slow wave high-power microwave source, the electron beam emitted from cathode (1) enters coaxial slow wave Gao Gong
The slow-wave structure region of rate microwave source, energy transmission to the synchronous mode in coaxial slow wave microwave source, including rotational symmetry
Quasi-TEM mode and non-rotationally-symmetric quasi- TEv1Mode；
3.2. to be partially converted into Quasi-TEM mode non-for the noncoherent boundary of slow-wave structure (3) in coaxial slow wave high-power microwave source
Synchronous TM01Mode makes quasi- TEv1Mode is partially converted into asynchronous TMv1Mode；
3.3. in coaxial slow wave high-power microwave source, TM01The m of mode is equal to N-3, leads to electronic conductance Ge=0, TM01Mode
Not with electron beam transducing, microwave source do not inhibit the Quasi-TEM mode of rotational symmetry；Non-rotationally-symmetric TMv1The m of mode is not equal to N-
3, lead to electronic conductance Ge> 0, slow-wave structure is by asynchronous TMv1The energy transmission electron beam of mode, and TMv1The energy of mode
Amount is from quasi- TEv1It is transformed in mode, leads to non-rotationally-symmetric quasi- TEv1The gross energy of mode reduces；It is vibrated in microwave source
Initial stage, Quasi-TEM mode and quasi- TEv1The energy difference of mode is little, with quasi- TEv1The gross energy of mode reduces, rotational symmetry
The accounting of Quasi-TEM mode increases, and gradually occupies leading position；As the accounting of Quasi-TEM mode increases, electron beam passes to standard
The energy of TEM mode further increases, and passes to non-rotationally-symmetric quasi- TEv1The energy of mode further decreases, full in microwave
Before, non-rotational symmetry mode is totally constrained.
2. the suppressing method of non-rotational symmetry mode, feature in coaxial slow wave high-power microwave source as described in claim 1
Be 1.3.1 walk it is described according to high-power microwave source to efficiency, the demand of power, the method for determining the shape of slow-wave structure is:
If pursuing high efficiency, rectangle ripple is chosen；If pursuing high power, cosine or triangle ripple are chosen；If desired efficiency and power
Optimum balance selects trapezoidal ripple.
3. the suppressing method of non-rotational symmetry mode, feature in coaxial slow wave high-power microwave source as described in claim 1
It is that the electromagnetic simulation software refers to HFSS i.e. High Frequency Structure Simulator or CST i.e. Computer
Simulation Technology。
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| CN116959936A (en) * | 2023-07-31 | 2023-10-27 | 中国人民解放军国防科技大学 | Combined periodic slow wave structure applied to high-power microwave device |
| CN117892517A (en) * | 2024-01-09 | 2024-04-16 | 中国工程物理研究院应用电子学研究所 | Digital modeling method for high-power microwave transmission |
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| CN103545579A (en) * | 2013-10-26 | 2014-01-29 | 中国人民解放军国防科学技术大学 | Method for purifying output modes of slow-wave high-power microwave source |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116959936A (en) * | 2023-07-31 | 2023-10-27 | 中国人民解放军国防科技大学 | Combined periodic slow wave structure applied to high-power microwave device |
| CN116959936B (en) * | 2023-07-31 | 2024-01-05 | 中国人民解放军国防科技大学 | Combined periodic slow wave structure applied to high-power microwave device |
| CN117892517A (en) * | 2024-01-09 | 2024-04-16 | 中国工程物理研究院应用电子学研究所 | Digital modeling method for high-power microwave transmission |
| CN117892517B (en) * | 2024-01-09 | 2024-09-20 | 中国工程物理研究院应用电子学研究所 | Digital modeling method for high-power microwave transmission |
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