An extended interaction oscillator based on staggered double-gate

Abstract

In order to solve the application problem of the traditional extended interaction device in the high frequency terahertz frequency band, the characteristic impedance of the resonant cavity and the interaction efficiency need to be improved, and the most effective method to improve the impedance is to introduce a new extended interaction resonant cavity operating mode. The application discloses an extended interaction oscillator based on staggered double grids, on the basis of the existing extended interaction oscillator, two groups of gratings are staggered along the z direction to form a staggered double grid structure, and the coupling input and output structure is moved to the electron beam injection end outside the y direction resonant cavity, so that a new operating mode, i.e. close to 2pi mode, is generated, stronger interaction effect is generated, the coupled energy is output to the rectangular waveguide through the coupling input and output structure, so that the purpose of reducing the interaction circuit length of the extended interaction oscillator is achieved.

Description

Technical Field

[0001] This invention belongs to the field of vacuum electronic device technology, and more specifically, relates to an extended interaction oscillator based on interleaved dual gates. Background Technology

[0002] Extended interaction oscillators are important vacuum electronic devices with features such as simple design, easy fabrication, high power, high efficiency, and good stability. They have a wide range of applications in many fields such as radar and plasma diagnostics.

[0003] Traditional extended interaction oscillators include Chinese invention patent application CN116844929A, published on October 3, 2023, entitled "Dual-strip injection gap coupled slow wave structure and extended interaction oscillator and method," such as... Figure 1 As shown, it consists of two sets of gratings 2 symmetrically distributed about the central axis, electron beam channels 3, and rectangular coupling cavities (resonant cavities) 1, with each set of gratings 2 aligned with each other. This extended interaction oscillator typically operates in 2π mode. The rectangular coupling cavity has a low characteristic impedance and low interaction efficiency, which leads to an excessively long interaction circuit in the extended interaction oscillator. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and propose an extended interaction oscillator based on interleaved dual grids to improve the characteristic impedance of the entire resonant cavity, thereby improving the interaction efficiency and reducing the interaction circuit length of the extended interaction oscillator.

[0005] To achieve the above-mentioned objectives, the present invention provides an extended interaction oscillator based on interleaved double gratings, comprising a resonant cavity, an input electron beam channel and an output electron beam channel located at both ends of a central axis, two sets of gratings symmetrically distributed about the central axis, and a coupled input-output structure, characterized in that:

[0006] Both sets of gratings are rectangular with the same size and are symmetrically distributed about the central axis. The central axis is consistent with the z-direction, which is the direction of electron beam propagation. Each set of gratings is aligned along the z-direction and placed periodically. The horizontal direction (x-direction) is connected to the inner wall of the resonant cavity, and the vertical direction (y-direction) is separated from the inner wall of the resonant cavity. The two sets of gratings are staggered along the z-direction to form an staggered double-grating structure and are placed inside the resonant cavity.

[0007] The input electron beam channel and the output electron beam channel are aligned with the gap between the two sets of gratings. The electron beam is injected from the input electron beam channel, enters the resonant cavity through the input section electron beam channel, enters the output electron beam channel through the gap between the two sets of gratings, and is output through the output electron beam channel.

[0008] The coupled input-output structure is located at the electron injection end outside the resonant cavity in the y-direction, and is used to connect the resonant cavity to the rectangular waveguide. The coupled energy is output to the rectangular waveguide through the coupled input-output structure.

[0009] The objective of this invention is achieved as follows:

[0010] To address the application challenges of traditional extended interaction devices in the high-frequency terahertz band, it is necessary to improve the characteristic impedance and interaction efficiency of the resonant cavity. The most effective method to improve impedance is to introduce a new operating mode for the extended interaction resonant cavity. This invention, based on an interleaved double-grating extended interaction oscillator, builds upon existing extended interaction oscillators by interleaving two sets of gratings along the z-direction to form an interleaved double-grating structure. Simultaneously, the coupled input / output structure is moved to the electron injection end outside the resonant cavity in the y-direction, thereby generating a new operating mode, close to the 2π mode, producing a stronger interaction effect. The coupled energy is output to the rectangular waveguide through the coupled input / output structure, thus reducing the interaction circuit length of the extended interaction oscillator. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of an existing extended interaction oscillator;

[0012] Figure 2 This is a three-dimensional structural cross-sectional schematic diagram of a specific embodiment of the extended interactive oscillator based on interleaved dual grids of the present invention;

[0013] Figure 3 yes Figure 2 The figure shows a cross-sectional view of the center point of the extended interaction oscillator based on interleaved dual grids along the z direction.

[0014] Figure 4 yes Figure 2 The diagram shows the eigensimulation of the true z-direction electric field lines of an extended interactive oscillator based on interleaved dual grids.

[0015] Figure 5 This is a comparison chart of the interaction efficiency of three different working modes;

[0016] Figure 6 yes Figure 2 The S-parameters of the extended interactive oscillator input-output structure based on interleaved dual grids are shown.

[0017] Figure 7 This is a graph showing the output signal changing over time.

[0018] Figure 8 It is the FFT spectrum of the input and output signals;

[0019] Figure 9 It is the phase space diagram after the output signal has stabilized. Detailed Implementation

[0020] The specific embodiments of the present invention will now be described with reference to the accompanying drawings to enable those skilled in the art to better understand the invention. It should be particularly noted that in the following description, detailed descriptions of known functions and designs that might obscure the main content of the invention will be omitted here.

[0021] Figure 2 , 3 These are a three-dimensional structural cross-sectional view of a specific embodiment of the extended interactive oscillator based on interleaved double grids of the present invention, and a cross-sectional view of the center point in the x-direction along the z-direction.

[0022] In this embodiment, as Figure 2 , 3 As shown, the extended interaction oscillator based on interleaved double gratings of the present invention includes a resonant cavity 1, an input electron beam channel 201 and an output electron beam channel 202 located at both ends of the central axis, two sets of gratings symmetrically distributed about the central axis, namely the upper grating 301 and the lower grating 302, and a coupling input-output structure 4.

[0023] Two sets of gratings 301 and 302, symmetrically distributed about the central axis, are both rectangles of the same size. The central axis is consistent with the z-direction, i.e. the direction of electron beam transmission. Each set of gratings 301 and 302 is aligned along the z-direction and placed periodically. The lateral direction (x-direction) is connected to the inner wall of the resonant cavity 1, and the longitudinal direction (y-direction) is separated from the inner wall of the resonant cavity. The two sets of gratings 301 and 302 are staggered along the z-direction to form an staggered double-grating structure, which is placed inside the resonant cavity 1.

[0024] The input electron beam channel 201 and the output electron beam channel 202 are aligned with the gap between the two sets of gratings. The electron beam is injected from the input electron beam channel 201, enters the resonant cavity 1 through the input electron beam channel 201, enters the output electron beam channel 202 through the gap between the two sets of gratings, and is output through the output electron beam channel 202.

[0025] The coupling input-output structure 4 is located at the electron injection end outside the resonant cavity in the y direction. It is used to connect the resonant cavity 1 to the rectangular waveguide. The coupled energy is output to the rectangular waveguide through the coupling input-output structure.

[0026] To address the problem of excessively long grating periods in the resonant cavity of traditional extended interaction oscillators, this invention provides an extended interaction resonant cavity structure based on interleaved double gratings. Two sets of gratings 301 and 302 are interleaved along the z-direction to form an interleaved double grating structure. Simultaneously, the coupled input / output structure 4 is moved to the electron injection end outside the resonant cavity in the y-direction, thereby generating a new operating mode, namely a near-2π mode, achieving the goal of reducing the interaction circuit length of the extended interaction oscillator.

[0027] In this embodiment, the resonant cavity 1 is made of oxygen-free copper material, such as... Figure 2 As shown, gratings 301 and 302 in the resonant cavity are also made of oxygen-free copper. The upper grating 301 is closer to the coupling input / output structure 4 and contains 11 cycles. The lower grating 302 is farther away from the coupling input / output structure 4 and contains 12 cycles. They are staggered into half cycles, that is, each upper grating is directly opposite the gap between the two lower gratings. At this time, a new working mode of 23π / 12 mode is generated.

[0028] The length of one period in the z-direction is p, the lengths of the grating in the z-direction and y-direction are g and h respectively, the height of the electron beam channel in the y-direction is t, the length of the input electron beam channel 201 is A1, the length of the output electron beam channel 202 is A2, the lengths of the external BJ1400 standard rectangular waveguide 5 in the z-direction and y-direction are sz and sy respectively, the height of the resonant cavity 1 in the y-direction is cuy, and the lengths of the coupled input-output structure 4 in the z-direction and y-direction are oz and oy respectively.

[0029] For the x-direction, such as Figure 1 As shown, the resonant cavity 1 is connected to a BJ1400 standard rectangular waveguide with a length of sx in the x direction, each grating has a length of w in the x direction, the electron beam channel has a length of ex in the x direction, and the coupling input-output structure 4 has a length of ox in the x direction.

[0030] In this embodiment, the resonant cavity is made of oxygen-free copper with a conductivity σ = 2.2 × 10⁷ S / m. The specific structural parameters are as follows (unit: mm): t = 0.3, ex = 1.2, p = 0.83, h = 1.6, g = 0.25, A1 = 9.96, A2 = 3.32, cuy = 16.2, w = 1.6, sx = 2.54, sy = 6, sz = 1.27, ox = 1.6, oy = 0.1, oz = 1.8.

[0031] Using 3D electromagnetic simulation software, Figure 1 The structure and dimensions shown are used to simulate and calculate the high-frequency characteristic parameters of the extended interactive oscillator based on interleaved dual grids of the present invention.

[0032] Figure 3 This is a schematic diagram of the intrinsically simulated true z-direction electric field lines, as shown below. Figure 3 As shown, the electric field lines cross zero 23 times, so the operating mode is 23π / 12 mode.

[0033] The electric field strengths of the 23 / 12π, 2π, and 11π / 6 modes were imported into MATLAB to calculate the equivalent impedance of different modes. The equivalent impedance is a parameter that evaluates whether the resonant cavity can effectively interact with the electron beam. Its calculation formula is as follows:

[0034]

[0035] ω0=2πf0

[0036]

[0037] E z For the longitudinal electric field, β e Where f is the propagation constant of the electron beam, f0 is the resonant frequency of the resonant cavity, and W... s This refers to the energy of the resonant cavity. The effective impedance (MΩ) of the resonant cavity (EISRC) was calculated using MATLAB. 2 R / Q).

[0038] like Figure 4 As shown, when the operating voltage varies between 19kV and 20kV, the 23 / 12π mold has the strongest effective impedance, that is, the strongest modulation effect on the electron beam. Therefore, the resonant cavity in this mode has the strongest modulation efficiency.

[0039] Using a time-domain solver, with the background material set as oxygen-free copper (σ = 2.8 × 10⁻⁶), 7 In the case of S / m), for a center frequency of 96.5GHz, S 11 The value is -16.56 dB, and the group delay τ is 29.65 nanoseconds. For example... Figure 5 As shown, in the frequency range of 96.4-96.54 GHz, S 11 Below -10dB.

[0040] Figure 6 This demonstrates the maximum output power of the extended interactive staggered resonator. For example... Figure 6 As shown, the electron beam begins to cluster at 20 ns, and the output signal tends to stabilize at 100 ns, with no oscillation occurring within 100 ns.

[0041] Figure 7 The spectrum diagrams of the input and output signals of the extended interactive staggered resonator are shown, such as... Figure 7 As shown, the spectrum of the output signal is relatively clean, with no signs of oscillation. When the input frequency is 96.5 GHz and the input power is 5 mW, the saturated output power is 655.22 W, and the corresponding gain is 61.87 dB.

[0042] Figure 8 This is an electron phase space diagram of the electron beam-wave interaction process, which can clearly reflect the modulation effect of the electromagnetic field on the electron beam.

[0043] Although the illustrative specific embodiments of the present invention have been described above to enable those skilled in the art to understand the invention, it should be understood that the invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of the present invention are protected.

Claims

1. An extended interaction oscillator based on interleaved dual gratings, comprising a resonant cavity, an input electron beam channel and an output electron beam channel located at both ends of a central axis, two sets of gratings symmetrically distributed about the central axis, and a coupled input-output structure, characterized in that: Both sets of gratings are rectangular with the same size and are symmetrically distributed about the central axis. The central axis is consistent with the z-direction, which is the direction of electron beam propagation. Each set of gratings is aligned along the z-direction and placed periodically. The horizontal direction (x-direction) is connected to the inner wall of the resonant cavity, and the vertical direction (y-direction) is separated from the inner wall of the resonant cavity. The two sets of gratings are staggered along the z-direction to form an staggered double-grating structure and are placed inside the resonant cavity. The input electron beam channel and the output electron beam channel are aligned with the gap between the two sets of gratings. The electron beam is injected from the input electron beam channel, enters the resonant cavity through the input section electron beam channel, enters the output electron beam channel through the gap between the two sets of gratings, and is output through the output electron beam channel. The coupled input-output structure is located at the electron injection end outside the resonant cavity in the y-direction, and is used to connect the resonant cavity to the rectangular waveguide. The coupled energy is output to the rectangular waveguide through the coupled input-output structure. The two sets of gratings are symmetrically distributed about the central axis. The side closer to the coupling input / output structure is the upper grating, which contains 11 cycles, and the side farther from the coupling input / output structure is the lower grating, which contains 12 cycles. They are staggered into half cycles, meaning that each upper grating is directly opposite the middle of the gap between the two lower gratings.

2. The extended interactive oscillator based on interleaved dual grids according to claim 1, characterized in that, The resonant cavity and the grating within it are both made of oxygen-free copper.

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