A method for determining a micro-discharge threshold of a microwave component

Abstract

A kind of microwave component micro-discharge threshold determination method, comprising the following steps: (1) seed electron state initialization;(2) analysis microwave component internal electromagnetic field;(3) set time step, promote electron operation trajectory;(4) determine whether electron collides with microwave component surface, if not collide return (3);(5) calculate the energy, angle and electron and material interaction time of emitted secondary electron;(6) update electron state;(7) determine whether electron reaches the set simulation period;(8) according to the trend of electron number change with time determine whether micro-discharge occurs.The method more objectively and accurately characterizes the physical process of micro-discharge effect occurrence under high frequency, and can be used for the anti-micro-discharge design of high frequency microwave component.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of microwave component micro-discharge threshold determination method, belong to electronic science and technology field. BACKGROUND

[0002] With the strong demand for ultra-high speed data transmission and super capacity communication, the frequency-rich resource of millimeter wave or even terahertz band is very important for improving the capacity of communication satellite system, and is the first choice for developing very high flux communication and ultra-high speed data transmission. With the increase of frequency, the accurate analysis of micro-discharge effect of spaceborne microwave component will face new challenges. Due to the increase of frequency, the transit order of electron in electromagnetic field in microwave component of the same size increases, and the deviation of electron emission phase will further exacerbate the deviation of electron motion trajectory. In the traditional micro-discharge simulation method, it is considered that the secondary electron is emitted immediately after collision in the material, and the time occupied by the transmission, scattering and emission of electron in the material inside the microwave component is not included. When the time consumed by the process of electron collision to the surface of microwave component and emission is comparable to the microwave period, the emission time of secondary electron is no longer the collision time of incident electron, and the electromagnetic field in which the secondary electron enters the microwave component must be updated. Therefore, the analysis method for micro-discharge threshold of high-frequency microwave component has important value for accurate anti-micro-discharge design, so as to avoid the serious consequences caused by micro-discharge, such as resonance device detuning, noise level rising, output power decreasing, even causing low-pressure discharge and damaging the surface of microwave component. SUMMARY

[0003] The technical problem solved by the present application is to overcome the shortcomings of the prior art and provide a high-frequency microwave component micro-discharge threshold determination method, which takes into account the time of electron motion and interaction in the material, solves the phase coupling relationship of electron on the surface of microwave component material and space electromagnetic field, and provides a new method for anti-micro-discharge design of microwave component at high frequency.

[0004] The technical scheme of the application is: a microwave component micro-discharge threshold determination method, comprising:

[0005] (1) randomize the initial state of N seed electrons according to the probability distribution;

[0006] (2) calculate the electromagnetic field inside the microwave component according to the structure of the microwave component to be analyzed, input frequency and input power;

[0007] (3) set the time step Δ t , calculate the electron motion trajectory according to the electromagnetic field action on the electron in the microwave component;

[0008] (4) judge whether the electron collides to the surface of microwave component, if not, return to step (3) for the next Δt If a collision occurs with the surface of a microwave component, the electronic state at the moment of collision is recorded, and the process proceeds to step (5).

[0009] (5) Calculate the energy and angle of the emitted secondary electrons, as well as the interaction time between the electrons and the material, based on the electron state at the moment of collision;

[0010] (6) Update the electronic state, using the collision location, the energy and angle of the emitted secondary electron, and the phase of the updated electron as the new electronic state:

[0011] (7) Determine whether the new electronic phase has reached the preset simulation period. If not, return to step (3) to continue the calculation. If all electronic phases have reached the simulation period, then count each Δ t The number of electrons at time t, and proceed to step (8);

[0012] (8) Based on the trend of the number of electrons over time, determine whether the microwave component to be analyzed undergoes micro-discharge at the input frequency and power. If the number of electrons remains constant over time, the input power is considered to be the micro-discharge threshold of the microwave component at the input frequency. If the number of electrons changes over time, adjust the input power and return to step (2).

[0013] In step (1), the initial states of the N seed electrons are randomized according to a probability distribution, including: randomizing the initial position of the electrons to any position of the gap to be simulated within the microwave component;

[0014] Randomize the initial electron energy according to a normal probability distribution or other probability distribution;

[0015] The initial angle of the electron is randomized according to the arcsine probability distribution;

[0016] The initial azimuth angle of the electron is randomized according to a uniform distribution within [0, 2π].

[0017] The initial phase of the electrons is uniformly distributed within the first microwave cycle.

[0018] When calculating the electromagnetic field inside the microwave component, existing electromagnetic calculation software, including CST and HESS, is used to calculate and export the electromagnetic field values ​​of each internal grid.

[0019] In step (3), the electron calculated for the first time is the seed electron, and the electron state during propulsion is the initial state of the seed electron.

[0020] In step (3), the trajectory of the electron in the electromagnetic field is advanced by the fourth-order Runge-Kutta method or other differential equation methods.

[0021] In step (3), the initial state of electron propulsion is the electron state corresponding to time ψ_be; after propulsion, the electron state is updated to i. Δ t The corresponding electronic state.

[0022] In step (3), the time step of the electron's trajectory in the electromagnetic field is the phase ψ_be and i before the electron propagates. Δ t The difference, where (i-1) Δ t≤ ψ_be Δ t , where i represents the number of times the time step is advanced.

[0023] In step (4), the electronic state includes the electronic position, electronic energy, the angle between the electron and the surface of the component, the electronic azimuth angle, and the electronic phase.

[0024] In step (5), the number of emitted secondary electrons and their corresponding energies and angles are determined by a secondary electron emission model, which may include the Furman model, the Vaughan model, or by calculation using the Monte Carlo method.

[0025] In step (5), the interaction time between electrons and materials is obtained by attosecond laser testing, or calculated by the Monte Carlo method, or calculated by the electron range formula.

[0026] In step (6), the phase of the updated electron is the electron phase at the time of collision, plus the sum of the interaction time between the electron and the material.

[0027] The step of adjusting the input power and returning to step (2) if the number of electrons changes over time includes: if the number of electrons increases over time, it is assumed that micro-discharge will occur at this power, so the input power is reduced and the process returns to step (2); if the number of electrons decreases over time, it is assumed that micro-discharge will not occur at this power, so the input power is increased and the process returns to step (2).

[0028] The advantages of this invention compared to the prior art are:

[0029] (1) This invention proposes a more complete method for simulating the micro-discharge threshold of microwave components, which solves the phase coupling relationship between electrons on the surface of microwave component materials and the electromagnetic field of microwave component space at high frequencies, and reflects a more fundamental micro-discharge process;

[0030] ​(2) The method of the present invention takes into account the time of electron movement and interaction in the material during the micro discharge simulation process, and solves the simulation phase deviation problem caused by the time error of the high-frequency secondary electron emission process compared with the microwave period.

[0031] (3) The method of the present invention synchronizes the phase of the secondary electron after emission to the trajectory advancement time, which simplifies the analysis process and has high calculation accuracy. It has guiding significance for the anti-micro-discharge design of high-frequency microwave components. Attached Figure Description

[0032] Figure 1 This is a flowchart of the technology of the present invention;

[0033] Figure 2 The variation trend of particle number over time at 570V for a 100GHz, 0.1mm parallel plate without using the method of this invention;

[0034] Figure 3 The figure shows the variation trend of particle number over time at 650V, 670V, 680V and 690V for a 100GHz, 0.1mm parallel plate using the method of the present invention. Detailed Implementation

[0035] like Figures 1-3 As shown, the present invention provides a method for determining the micro-discharge threshold of a microwave component, comprising the following steps:

[0036] (1) The initial states of the N seed electrons are randomized according to a probability distribution that conforms to the given conditions;

[0037] (1a) The initial positions (x_init, y_init, z_init) of the electrons are randomized to any position of the gap to be simulated within the microwave component;

[0038] (1b) The initial electron energy E_init can be randomized according to a normal distribution or other probability distributions;

[0039] (1c) The initial exit angle θ_init of the electron is randomized according to the arcsine probability distribution;

[0040] (1d) The initial azimuth angle φ_init of the electron is randomized according to a uniform distribution within [0, 2π].

[0041] (1e) The initial phase ψ_init of the electron is uniformly distributed within the first microwave cycle;

[0042] (2) Based on the structure of the microwave component and the input frequency f in and input power W In calculating the internal electromagnetic field of microwave components;

[0043] (2a) Electromagnetic calculations inside microwave components can be performed using existing electromagnetic calculation software, such as CST and HESS, to calculate and export the electromagnetic field values ​​of each internal grid.

[0044] (3) Set the time step Δ t The trajectory of electrons is propelled by the electromagnetic field acting on them in the microwave component.

[0045] (3a) The first electron to propel the electron is the seed electron. The electron state at the time of propulsion is the initial state of the seed electron, that is, the electron position (x_be, y_be, z_be) = (x_init, y_init, z_init), the electron energy E_be = E_init, the electron exit plane angle θ_be = θ_init, the electron azimuth angle φ_be = φ_init, and the electron phase ψ_be = ψ_init.

[0046] (3b) The propulsion of the electron's trajectory in the electromagnetic field can be solved using the fourth-order Runge-Kutta method or other differential equation methods;

[0047] (3c) The time step of the electron's trajectory in the electromagnetic field is the phase ψ_be before the electron's propulsion to i. Δ t , where (i-1) Δ t≤ ψ_be Δ t where i = 1, 2, ...;

[0048] (3d) The initial state of electron propulsion is the electron state corresponding to time ψ_be;

[0049] (3e) Change i Δ t After solving the electromagnetic field at time 1, the electronic parameters are updated to include the electronic position (x_af, y_af, z_af), electronic energy E_af, electron exit plane angle θ_af, electron azimuth angle φ_af, and electronic phase ψ_af. When the electron trajectory advances again... ， The electron state at this moment is the starting state of the electron at the next moment, that is, x_be=x_af, y_be=y_af, z_be=z_af, E_be=E_af, θ_be=θ_af, φ_be=φ_af, ψ_be=ψ_af;

[0050] ​(4) Determine whether the electron collides with the surface of the microwave component. If it does not collide, return to step (3). If it collides with the surface of the microwave component, record the state of the electron at the moment of collision (collision position x_impact, y_impact, z_impact, collision energy E_impact, angle with the collision surface θ_impact, collision azimuth angle φ_impact, collision phase ψ_impact).

[0051] (5) Based on the collision energy E_impact and the collision angle θ_impact, calculate the state of the secondary electron emitted by the electron in the microwave component material properties and surface state (emission energy E_emit, emission angle θ_emit, emission azimuth angle φ_emit, and interaction time t_emit between the electron and the material).

[0052] (5a) The number of electrons emitted and the emission energy can be solved by secondary electron emission models such as the Furman model and the Vaughan model, or calculated by the Monte Carlo method;

[0053] (5b) The emission time of electrons can be measured by instruments such as attosecond lasers or calculated by the Monte Carlo method or by the electron range formula;

[0054] (6) Update the electronic state, using the collision position, emitted electron energy, angle, and updated phase as the new electronic state: x_be=x_impact, y_be=y_impact, z_be=z_impact, E_be=E_emit, θ_be=θ_emit, φ_be=φ_emit, ψ_be=ψ_impact+t_emit;

[0055] (7) Determine if the electron phase has reached the simulation period. If not, return to step (3) and continue. If all electrons have reached the simulation period, then count each Δ t The number of electrons at any given time;

[0056] (8) Determine the power W To determine if micro-discharge occurs at the input frequency and power, if the number of electrons increases with time, then the microwave component is considered to have undergone micro-discharge at that frequency and power; otherwise, it is considered not to have undergone micro-discharge. The process is repeated until the number of electrons remains essentially constant over time. Then, the input power is considered to be the micro-discharge threshold of the microwave component at that input frequency.

[0057] Example 1

[0058] Parallel flat plate, 0.1mm gap, 100GHz, surface made of Furman-Ag material.

[0059] (1) N=1000 seed electrons are produced.

[0060] 1000 seed electrons x_init in [0,10 -4 The interval is randomly distributed, y_init=0, z_init=0;

[0061] Seed electron energy E_init satisfies the distribution σ=3eV, μ=5eV;

[0062] The angle between the seed electron and the x-direction satisfies the distribution... ;

[0063] The azimuth angle φ_init of the seed electron is randomly selected in the interval [0, 2π].

[0064] Seed electron phase ψ_init in [0, Random distribution, Twave=1 / f=10 -11 s;

[0065] (2) Calculation d Electromagnetic field of a parallel plate with a gap of 0.1mm, input power set to 690V, frequency set to... f =100GHz, the electromagnetic field inside a parallel plate structure is determined by the following formula.

[0066] E =[- , 0, 0] B =[0, , 0];

[0067] (3) The time step is set to Δ t =Twave / 50, calculates the trajectory of the electron.

[0068] The propagation of the electron's trajectory in the electromagnetic field is solved using the fourth-order Runge-Kutta method.

[0069]

[0070] Initially, there is a seed electron. The state of the seed electron when it enters the electromagnetic field is: electron position (x_be, y_be, z_be) = (x_init, y_init, z_init), electron energy E_be = E_init, the angle between the electron and the x-direction θ_be = θ_init, the electron azimuth angle φ_be = φ_init, and the electron phase ψ_be = ψ_init.

[0071] The step size of electronic propulsion is [ψ_be,i Δt],(i-1) Δt ≤ ψ_be < i Δt, solve for the electron trajectory according to the above formula. At the first solution is

[0072] [cosθ_init, sinθ_init cosφ_init, sinθ_init sinφ_init];

[0073] The electromagnetic fields E, B are given by the formula in step (2), and the calculated i The electron state after Δt is: x_af, y_af, z_af, E_af, θ_af, φ_af, ψ_af;

[0074] (4) Determine whether the electron collides with the surface of the microwave component, that is, whether the x-direction trajectory satisfies x_af ≥ 0.1 mm or x_af ≤ 0 mm,

[0075] If 0 < x_af < 0.1 mm, at this time the electron does not collide with the surface of the microwave component, then update the electron state to x_be = x_af, y_be = y_af, z_be = z_af, E_be = E_af, θ_be = θ_af, φ_be = φ_af, ψ_be = ψ_af, and return to step (3) to advance the electron trajectory;

[0076] If x_af ≥ 0.1 mm or x_af ≤ 0 mm, record the state of the electron when x_af is closest to = 0.1 mm or x = 0 mm as the electron collision state: position x_impact, y_impact, z_impact, collision energy E_impact, angle with the x-direction θ_impact, collision azimuth angle φ_impact, collision phase ψ_impact;

[0077] (5) According to the collision energy E_impact(j) and the collision angle θ_impact(j), in this embodiment, the Furman model is used to calculate the energy E_emit of the outgoing electron, and the outgoing angle θ_emit is generated according to the probability distribution The outgoing azimuth angle φ_emit is randomly distributed in [0, 2π]. In this embodiment, t_emit is estimated according to the formula and then t_emit is set to 2 ps;

[0078] (6) Update the electronic state, using the collision position, emitted electron energy, angle, and updated phase as the new electronic state: x_be=x_impact, y_be=y_impact, z_be=z_impact, E_be=E_emit, θ_be=θ_emit, φ_be=φ_emit, ψ_be=ψ_impact+2ps;

[0079] (7) Determine if ψ_be >= the set simulation period.

[0080] If ψ_be < simulation period, the updated electronic state in step (6) is used as the starting state for trajectory advancement in step (3), and the process returns to step (3) to advance the trajectory.

[0081] If ψ_be >= simulation period, record the state of the electron. Once the phases of all electrons have reached the simulation period, then calculate the state of each Δ. t The number of electrons at any given time.

[0082] (8) Determine the power W Whether a micro-discharge occurs under the input power is determined by whether the number of electrons increases with time. If the number of electrons increases with time, it is considered that a micro-discharge has occurred at that frequency and power. Otherwise, it is considered that no micro-discharge has occurred. In this embodiment, when the input power is 690V, the number of electrons increases with time, so it is considered that a micro-discharge will occur under this structure at 690V. By changing the input power and returning to step (2), the curves of the number of electrons changing with time under different voltages can be obtained.

[0083] Figure 2 A comparison of micro-discharge analysis using traditional methods and the method of this invention is presented. It can be seen that: using the traditional method, which does not consider electron scattering and emission time in the material, the number of particles tends to stabilize around 570V. 570V can be considered the micro-discharge threshold for this structure. Figure 2 Using the method of the invention, when electrons collide with the surface of the plate, considering the movement time of electrons in the material (calculated as 2 ps in the embodiment), the simulation results of the method of the invention show that the change trend of the number of electrons at 670V tends to be stable. Figure 3 Therefore, it can be seen that for high-frequency bands, when the interaction time between electrons and materials is comparable to the period of the electromagnetic field, the method of this invention is required to obtain the micro-discharge threshold more accurately.

[0084] The above description is merely the preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Contents not described in detail in this specification are well-known to those skilled in the art.

Claims

1. A method for determining the micro-discharge threshold of a microwave component, characterized in that, include: (1) Randomize the initial states of the N seed electrons according to the probability distribution; (2) Calculate the electromagnetic field inside the microwave component based on the structure, input frequency and input power of the microwave component to be analyzed; (3) Set the time step Δ t The trajectory of electrons is calculated based on the electromagnetic field acting on them in the microwave component. (4) Determine whether the electrons collide with the surface of the microwave component. If they do not collide, return to step (3) to proceed to the next Δ. t If a collision occurs with the surface of a microwave component, the electronic state at the moment of collision is recorded, and the process proceeds to step (5). (5) Calculate the energy and angle of the emitted secondary electrons, as well as the interaction time between the electrons and the material, based on the electron state at the moment of collision; (6) Update the electronic state, using the collision location, the energy and angle of the emitted secondary electron, and the phase of the updated electron as the new electronic state: (7) Determine whether the new electronic phase has reached the preset simulation period. If not, return to step (3) to continue the calculation. If all electronic phases have reached the simulation period, then count each Δ t The number of electrons at time t, and proceed to step (8); (8) Based on the trend of the number of electrons over time, determine whether the microwave component to be analyzed undergoes micro-discharge at the input frequency and power. If the number of electrons remains constant over time, the input power is considered to be the micro-discharge threshold of the microwave component structure at the input frequency. If the number of electrons changes over time, adjust the input power and return to step (2). In step (5), the number of emitted secondary electrons and their corresponding energies and angles are determined by a secondary electron emission model, which may include the Furman model, the Vaughan model, or by calculation using the Monte Carlo method. In step (5), the interaction time between electrons and materials is obtained by attosecond laser testing, or calculated by the Monte Carlo method, or calculated by the electron range formula; In step (6), the phase of the updated electron is the electron phase at the time of collision, plus the sum of the interaction time between the electron and the material.

2. The method for determining the micro-discharge threshold of a microwave component according to claim 1, characterized in that: In step (1), the initial states of the N seed electrons are randomized according to a probability distribution, including: randomizing the initial position of the electrons to any position of the gap to be simulated within the microwave component; Randomize the initial electron energy according to a normal probability distribution or other probability distribution; The initial angle of the electron is randomized according to the arcsine probability distribution; The initial azimuth angle of the electron is randomized according to a uniform distribution within [0, 2π]. The initial phase of the electrons is uniformly distributed within the first microwave cycle.

3. The method for determining the micro-discharge threshold of a microwave component according to claim 1, characterized in that: When calculating the electromagnetic field inside the microwave component, existing electromagnetic calculation software, including CST and HESS, is used to calculate and export the electromagnetic field values ​​of each internal grid.

4. The method for determining the micro-discharge threshold of a microwave component according to claim 1, characterized in that: In step (3), the electron calculated for the first time is the seed electron, and the electron state during propulsion is the initial state of the seed electron.

5. The method for determining the micro-discharge threshold of a microwave component according to claim 1, characterized in that: In step (3), the trajectory of the electron in the electromagnetic field is advanced by the fourth-order Runge-Kutta method or other differential equation methods.

6. The method for determining the micro-discharge threshold of a microwave component according to claim 1, characterized in that: In step (3), the initial state of electron propulsion is the electron state corresponding to time ψ_be; after propulsion, the electron state is updated to i. Δ t The corresponding electronic state.

7. The method for determining the micro-discharge threshold of a microwave component according to claim 6, characterized in that: In step (3), the time step of the electron's trajectory advancement in the electromagnetic field is the phase ψ_be and i before the electron's advancement. Δ t The difference, where (i-1) Δ t≤ ψ_be Δ t , where i represents the number of times the time step is advanced.​ 8. The method for determining the micro-discharge threshold of a microwave component according to claim 1, characterized in that: In step (4), the electronic state includes the electronic position, electronic energy, the angle between the electron and the surface of the component, the electronic azimuth angle, and the electronic phase.

9. The method for determining the micro-discharge threshold of a microwave component according to claim 1, characterized in that: The step of adjusting the input power and returning to step (2) if the number of electrons changes over time includes: if the number of electrons increases over time, it is assumed that micro-discharge will occur at this power, so the input power is reduced and the process returns to step (2); if the number of electrons decreases over time, it is assumed that micro-discharge will not occur at this power, so the input power is increased and the process returns to step (2).

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