CN-122001304-A - S-band transit time oscillator and method thereof

Abstract

The invention discloses an S-band transit time oscillator and a method thereof, and belongs to the technical field of high-power microwave devices. The device comprises an anode structure, an annular cathode and an output circular waveguide, wherein the anode structure is a wheel-shaped super-structure material unit array which is coaxially arranged up and down, an electron drift channel and three electromagnetic regulation cavities are formed through unit arrangement, the inter-cavity drift channel is in a cut-off state for working electromagnetic waves and is only coupled through bunching electrons, the annular cathode is vertically arranged with the anode to generate radial current, a cut-off cavity is arranged at a cathode port, the output circular waveguide and the electromagnetic regulation cavities are connected to form a single port, and a radiation TM01 mode is achieved and the maximum size of the radiation TM01 mode is smaller than the wavelength of the mode. The invention does not need an external magnetic field, and the output power reaches 1.03GW under the external 460kV voltage and 2.8kA current, the conversion efficiency is 80 percent at the highest, the device is compact and strong, and the device is suitable for light and small equipment, thereby solving the problems of difficult deployment and large volume of the traditional double-port.

Inventors

• LIU MEIQIN
• HUANG BAOYING
• HOU CHENGYANG
• WANG YAWEI
• SHANG ZHIQIANG

Assignees

• 西安交通大学

Dates

Publication Date

20260508

Application Date

20260113

Claims (10)

1. 1. An S-band transit time oscillator is characterized by comprising an anode structure, an annular cathode and an output circular waveguide, wherein the anode structure is a wheel-shaped super-structure material unit array which is coaxially arranged up and down, an electron drift channel and three electromagnetic regulation cavities are formed by unit arrangement of the wheel-shaped super-structure material unit array, the electron drift channel between the cavities is in a cut-off state for working electromagnetic waves, coupling is achieved among the cavities through beam-forming electrons, the annular cathode is vertically arranged with the anode structure and is used for generating radial current, a cut-off cavity is arranged at a cathode port of the anode structure, the output circular waveguide is connected with the electromagnetic regulation cavities to form a single-power output port, the output circular waveguide irradiates a forward TM01 mode, the maximum size of the output circular waveguide is smaller than the TM01 mode wavelength, and the wheel-shaped super-structure material unit array forms a slow wave interaction structure and is used for adjusting equivalent dielectric parameters of devices to achieve energy exchange and electron bunching of the electrons and electromagnetic waves.
2. 2. The S-band time-of-flight oscillator of claim 1, wherein the array of wheel-shaped metamaterial units comprises wheel-shaped metamaterial upper units and wheel-shaped metamaterial lower units, an axial spacing between the upper units and the lower units constituting the electron drift channel.
3. 3. The S-band time-of-flight oscillator of claim 2, wherein the upper and/or lower wheel-shaped metamaterial units are provided with a central cavity.
4. 4. The S-band time-of-flight oscillator of claim 3, wherein the bottom of the lower wheel-shaped metamaterial unit is provided with a central through hole.
5. 5. The S-band time-of-flight oscillator of claim 2, wherein the upper and/or lower wheel-shaped metamaterial units comprise inner and outer ring grooves.
6. 6. The S-band time-of-flight oscillator of claim 2, wherein the upper and lower wheel-shaped metamaterial units are connected by at least one unit connection rod.
7. 7. The S-band transit time oscillator of claim 2, wherein the central axis of the cell connecting rod forms an angle θ with the horizontal.
8. 8. The S-band time-of-flight oscillator of claim 7, wherein the maximum dimension of the output circular waveguide is its inner radius Rw and Rw < λ, where λ is the operating wavelength of TM01 mode.
9. 9. The S-band transit time oscillator of any one of claims 1 to 8, wherein the transit time oscillator has an operating frequency of 2.19GHz and an output power of 1.03GW at an applied voltage of 460kV and an operating current of 2.8 kA.
10. 10. A method of microwave generation based on an S-band transit time oscillator according to any one of claims 1 to 9, comprising the steps of: Applying high-voltage pulse between the annular cathode and the anode structure to enable the annular cathode to generate explosive electron emission so as to form an electron beam moving along the radial direction; the electron beam enters the electromagnetic regulation cavity through an electron drift channel between the wheel-shaped metamaterial unit arrays; In the electromagnetic regulating cavity, the electron beam interacts with an eigenmode field regulated by the slow wave interaction structure to realize the conversion of electron energy to microwave energy and speed modulation of the electron beam; Finally, the excited microwaves are radiated and output from the single power output port in a TM01 mode by the output circular waveguide connected with the electromagnetic regulation cavity, and the radiation process is constrained by the cut-off cavity at the cathode port.

Description

S-band transit time oscillator and method thereof Technical Field The invention belongs to the technical field of high-power microwave devices, and particularly relates to an S-band transit time oscillator and a method thereof. Background Radial transit time oscillators were proposed by Arman, mostron and Kwan in 1995 and 1996, respectively. The cathode has a large cathode emission area, electrons can move along the radial direction, so that the current density can be reduced, and the high-power microwave device is convenient to realize no magnetic field. The power conversion efficiency of the S-band three-cavity radial transit time oscillator proposed by the Shore-core technology institute at present can reach 53% at most, but the power conversion efficiency of the S-band three-cavity radial transit time oscillator needs two ports to output power, which is difficult to realize in engineering, the radius of the cavity is required to be larger than the cut-off wavelength of a working mode, and the power conversion efficiency is unfavorable for deployment in the requirements of the light and small equipment system at present. The invention provides a novel electromagnetic characteristic of a super-structure material, realizes that the radial three-cavity transit time oscillator works below the cut-off frequency, outputs electromagnetic waves at one port, and improves the compactness of the device. The novel wheel-shaped metamaterial unit is provided, an electronic drift channel is formed by arranging the design units and the units, the wheel-shaped metamaterial unit array is loaded in the circular waveguide, three electromagnetic regulation cavities are formed in appearance, and the power conversion efficiency can reach 80%. For guiding magnetic field systems, there are solenoid coils and permanent magnets, which have several drawbacks, firstly, that the solenoid coils need to be excited by an additional power supply system to generate a magnetic field, and that the power consumption of the power supply system reduces the efficiency of the whole system, and secondly, that the coils generate a large amount of heat energy under high-frequency and long-pulse conditions, thus requiring an additional cooling system. These additional systems, in addition to reducing the overall efficiency of the HPM system, add bulk and weight to the overall system. The main reason is that under certain weight and volume, the magnitude of the guiding magnetic field generated by the permanent magnet is limited. Therefore, in order to solve the problem of low efficiency commonly existing in permanent magnet encapsulation HPM sources, firstly, a low magnetic field high efficiency HPM source is researched, and secondly, the permanent magnet is optimally designed, and a higher magnetic field is generated as much as possible under a certain weight and volume. Further developments in light weight and miniaturization of HPM sources employing a guided magnetic field system have been hampered. The non-magnetic field relativity transit time oscillator is used as a high-power microwave source of a very potential narrow-band directional energy weapon, and has wide application prospect. The transit time oscillator is a microwave device based on interaction of electromagnetic waves and electron beams, and is generally applied to radar systems, electron countermeasure, plasma heating and basic science research. The He Yufang of the national defense science and the like in 2025 provides an X-band low-magnetic-field transit time oscillator, the volume and the weight of a magnetic field system are reduced by adopting a distributed magnet design method, the weight is about 5.67kG, the working frequency is 8GHz, the power is 1.17GW, and the power conversion efficiency is about 40.67%. The large-national defense science and Jujinchuan and the like propose a K-band coaxial transit time oscillator, and a two-stage modulation structure of cascade connection of a three-gap rectangular modulation cavity with high appearance quality factor and a single-gap trapezoidal modulation cavity with low appearance quality factor value is adopted, so that under the condition that the magnetic induction intensity of an externally-applied guide magnetic field is 0.74T, the microwave output power of 2.2GW is obtained, the beam wave power conversion efficiency is 44%, the output microwave frequency is 18.55GHz, and the proposal of the methods of spectral purity provides possibility for the light weight of a magnetic field system of the transit time oscillator and the improvement of the power conversion efficiency. Disclosure of Invention The invention aims to solve the technical problems in the prior art, and provides an S-band transit time oscillator, which improves the interaction efficiency of drift electrons and electromagnetic waves and realizes miniaturization by designing and arranging wheel-shaped super-structure material unit arrays forming electron drift channels