A switchable high-power microwave active pulse compression system

Abstract

The present invention discloses a switchable high-power microwave active pulse compression system, which belongs to the technical field of high-power microwave pulse compression. The system includes a microwave source, a switchable pulse compressor, a control circuit, and a radiation antenna; wherein the switchable pulse compressor includes a first circulator, a second circulator, a first gas discharge tube, a second gas discharge tube, an HT branch, a short-circuit piston, and a resonant cavity. The present invention switches the working state by controlling the circuit to achieve the effect of switching between the pulse compression mode - high peak power narrow pulse output and the pulse non-compression mode - high energy long pulse output; due to the use of an active pulse compression method, it is not limited to the controllable phase conditions of the microwave source signal, and can break through the limitation of the maximum peak power gain of passive pulse compression of 9, thereby achieving the purpose of high peak power gain.

Description

Technical Field

[0001] The invention belongs to the technical field of high-power microwave pulse compression, and in particular relates to a switchable high-power microwave active pulse compression system. Background Art

[0002] High Power Microwave (HPM) is a type of strong electromagnetic pulse with a frequency range of 0.5-300GHZ and a pulse peak power of more than 1MW. In the HPM system, the HPM source is the core of the system, which includes vacuum electronic devices such as magnetrons, klystrons, and gyrotrons, which can generate microwave long pulses with pulse widths of us and peak powers of MW. The long microwave pulses generated by the HPM source are widely used in high-energy electron RF acceleration, plasma heating and other fields. At the same time, in these application scenarios, sometimes the pulse width is not required, but the peak power is required to be high. The pulse compression technology can be used to compress the microwave long pulses generated by the HPM source into narrow pulses with a pulse width of hundreds or even tens of nanoseconds and a peak power increased by several times or even dozens of times.

[0003] The main principle of the microwave pulse compressor is to first store microwave energy in the energy storage cavity and then release it to achieve the purpose of pulse compression. The method of extracting energy by inverting the microwave pulse when the microwave pulse is about to end is a passive pulse compression method, and the method of extracting energy by changing the microwave parameters of the energy storage device, such as the coupling coefficient, when the microwave pulse is about to end is an active pulse compression method. The microwave source of the passive pulse compressor often uses a phase-controllable amplifier. This method is limited by its theory, and the power gain does not exceed 9. It is mainly used in the accelerator field. Active pulses are not limited to the condition that the microwave source phase must be controllable, and the power gain can exceed 9, reaching dozens of times, and are often used in the HPM field. Summary of the invention

[0004] The present invention provides a switchable high-power microwave active pulse compression system, which switches the working state by controlling the circuit to achieve the effect of switching between the pulse compression mode - high peak power narrow pulse output and the pulse non-compression mode - high energy long pulse output. The system adopts an active pulse compression method, which is not limited by the controllable conditions of the microwave source signal phase, and can break through the limitation of the maximum peak power gain of passive pulse compression of 9, and achieve the purpose of high peak power gain. The switchable high-power microwave active pulse compression system is combined with an HPM source to achieve the switching of the two signal outputs of high peak power narrow pulse / high energy long pulse, which can improve the performance of the overall HPM system.

[0005] The technical solution adopted by the present invention is:

[0006] A switchable high-power microwave active pulse compression system, characterized in that it comprises: a microwave source, a switchable pulse compressor, a control circuit, and a radiating antenna.

[0007] The microwave source adopts a high-power microwave vacuum electronic device to generate a long microwave pulse and transmit the long microwave pulse to the switchable pulse compressor.

[0008] The switchable pulse compressor is used to transmit the microwave long pulse directly to the radiation antenna, or to transmit it to the radiation antenna after compression.

[0009] The control circuit is used to control whether the switchable pulse compressor compresses the long microwave pulse.

[0010] The radiating antenna, acting as a load, radiates microwave pulses.

[0011] The switchable pulse compressor comprises a first circulator, a second circulator, a first gas discharge tube, a second gas discharge tube, an HT branch, a short-circuit piston, and a resonant cavity.

[0012] The first circulator and the second circulator both include an input end, a first output end, and a second output end; the input end of the first circulator is used to input the microwave long pulse; the first output end of the first circulator is connected to the input end of the second circulator, and a first gas discharge tube is arranged between the two ports; the second output end of the first circulator serves as a first channel to output uncompressed long pulses.

[0013] The first output end of the second circulator is connected to the input end of the HT branch, and the second output end is used as a second channel to output a compressed narrow pulse.

[0014] The output end of the HT branch is connected to the resonant cavity, the HT arm is connected to the short-circuit piston, and a second gas discharge tube is arranged in front of the short-circuit piston.

[0015] The first gas discharge tube and the second gas discharge tube are both active discharge tubes, and discharge is controlled by an external voltage source. After discharge, a short circuit is formed to reflect microwaves.

[0016] When the control circuit responds, the first gas discharge tube discharges to form a short-circuit, and the long microwave pulse is reflected by the short-circuit formed by the first gas discharge tube through the first circulator, and finally outputted intact through the second output end of the first circulator.

[0017] When the control circuit does not respond, the first gas discharge tube does not discharge, and the input microwave long pulse enters the second circulator through the first output end of the first circulator.

[0018] The short-circuit piston in the HT arm is adjusted to minimize the power entering the HT arm and allow the rest of the power to enter the resonant cavity. When the second gas discharge tube does not discharge, the short-circuit surface is located at the short-circuit piston surface, the coupling coefficient between the resonant cavity and the output end of the HT branch is large, and the system is in the energy storage stage. When the second gas discharge tube discharges to form a short-circuit surface, the coupling coefficient between the resonant cavity and the output end of the HT branch becomes smaller, and the energy in the resonant cavity is rapidly released and compressed into a narrow pulse, which is finally output through the second output end of the second circulator.

[0019] Furthermore, the short-circuit position of the second gas discharge tube changes by 1 / 4λ before and after discharge. g , realize impedance transformation, thereby changing the resonant cavity coupling coefficient, λ g Indicates the operating wavelength.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The pulse compressor in the present invention has a switchable function. It can select the compression mode to output a high peak power narrow pulse signal, or it can select the non-compression mode to output the original high energy long pulse signal, thereby realizing different applications of microwave pulses. When combined with the HPM source, it can improve the performance of the entire HPM system and has certain application potential in the HPM field.

[0022] (2) The present invention adopts active microwave pulse compression to improve the peak power gain, breaking through the limitation of the maximum peak power gain of passive pulse compression of 9. The peak power gain can reach dozens of times, and the peak power of the compressed pulse signal can reach a relatively high level. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 . A schematic diagram of the system of the present invention;

[0024] Figure 2 . A schematic diagram of the switchable pulse compression structure in the system of the present invention;

[0025] Figure 3 . Schematic diagram of the working principle of the gas discharge tube in the system of the present invention;

[0026] Figure 4 .It is a schematic diagram of the complete structure of the system of the present invention. DETAILED DESCRIPTION

[0027] In order to more clearly illustrate the purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Based on the above description, this embodiment designs a switchable high-power microwave active pulse compression system based on a magnetron working in the S band. The overall structure diagram of the system is shown in FIG. Figure 4 shown.

[0028] The HPM source of this system uses a magnetron, which generates a pulse width of τ L , a microwave long pulse signal with a peak power of P0 and a repetition rate of F0.

[0029] When the control circuit responds, the system switches to a non-compressed state, and the input microwave long pulse signal maintains the original long pulse state after passing through the system and is radiated by the antenna 1. The working principle is as follows: the microwave long pulse signal output by the magnetron is input into the first circulator through the waveguide. At this time, the control circuit responds and controls the pulse response of the ignition electrode voltage source 1, so that the ignition electrode of the first gas discharge tube is connected to a high voltage. Therefore, the first gas discharge tube discharges and forms a short-circuit between the two circulators. The input signal is reflected by the short-circuit and enters the first circulator again. It is output through the second output end of the first circulator as the feed source of the antenna 1, and the original peak power P0 and pulse width τ are maintained. L Radiated via antenna 1.

[0030] When the control circuit does not respond, the system switches to a compression state, and the input microwave long pulse signal is compressed into a high peak power narrow pulse state after passing through the system and radiated out by antenna 2. The working principle is as follows: when the control circuit does not respond, the ignition electrode voltage of the first gas discharge tube is in a disconnected state, so the first gas discharge tube does not discharge, the first gas discharge tube does not form a short circuit, and the first circulator and the second circulator are in a pass state. The input microwave long pulse signal enters the second circulator through the first output end of the first circulator.

[0031] The signal entering the second circulator enters the HT branch through the first output terminal, and the voltage pulse of the ignition electrode voltage source 2 of the second gas discharge tube in the HT arm is set to a few hundred nanoseconds τ before the end of the input pulse. T So when the input pulse τ T During the time before, the second gas discharge tube ignition electrode voltage source 2 does not respond, that is, the second gas discharge tube does not discharge, so the second gas discharge tube is in a pass state. Part of the energy transmitted into the HT arm enters the resonant cavity after being reflected by the short-circuit piston. By adjusting the position of the short-circuit piston, the energy entering the HT arm can be minimized. Figure 3 As shown, at this time, the short-circuit surface of the HT branch arm is at T, and the coupling coefficient between the resonant cavity and the HT branch output end is large.

[0032] In τ T In the time before τ, the system is in the energy storage stage, when the input pulse is stored in the resonant cavity; T When the second gas discharge tube ignition electrode voltage source 2 starts to respond, the second gas discharge tube starts to discharge, forming a short circuit. Figure 3 At this time, the short-circuit reference surface in the HT arm changes from the original T surface to the T′ surface; through reasonable design, the distance between the two is 1 / 4λg , realizing impedance transformation, which will reduce the coupling coefficient between the resonant cavity and the transmission waveguide, and the energy stored in the resonant cavity can be released quickly. The signal output by the resonant cavity is a compressed high peak power narrow pulse microwave signal with a peak power of P S , pulse width is τ S , output through the second output end of the second circulator as the feed source of antenna 2 and radiated through antenna 2.

[0033] By adding a control circuit to the pulse compression system to achieve state switching, the system can output two types of microwave pulses: high-peak power narrow pulses / high-energy long pulses. The system can also be further used to establish a high-power microwave array, which has certain application potential in the HPM field.

Claims

1. A switchable high-power microwave active pulse compression system, characterized in that: include: Microwave source, switchable pulse compressor, control circuit, radiating antenna; The microwave source adopts a high-power microwave vacuum electronic device to generate long microwave pulses and transmit them to the switchable pulse compressor; The switchable pulse compressor is used to transmit the microwave long pulse directly to the radiation antenna, or transmit it to the radiation antenna after compression; The control circuit is used to control whether the switchable pulse compressor compresses the microwave long pulse; The radiating antenna, as a load, radiates microwave pulses; The switchable pulse compressor comprises a first circulator, a second circulator, a first gas discharge tube, a second gas discharge tube, an HT branch, a short-circuit piston, and a resonant cavity; The first circulator and the second circulator both include an input end, a first output end, and a second output end; the input end of the first circulator inputs the microwave long pulse; The first output end of the first circulator is connected to the input end of the second circulator, and a first gas discharge tube is arranged between the two ports; the second output end of the first circulator outputs uncompressed long pulses as a first channel; The first output end of the second circulator is connected to the input end of the HT branch, and the second output end is used as a second channel to output a compressed narrow pulse; The output end of the HT branch is connected to the resonant cavity, the HT arm is connected to the short-circuit piston, and a second gas discharge tube is arranged in front of the short-circuit piston; The first gas discharge tube and the second gas discharge tube are both active discharge tubes, and discharge is controlled by an external voltage source. After discharge, a short circuit is formed to reflect microwaves.

2. A switchable high-power microwave active pulse compression system according to claim 1, characterized in that: When the control circuit responds, the first gas discharge tube discharges to form a short-circuit, and the microwave long pulse is reflected by the short-circuit formed by the first gas discharge tube through the first circulator, and finally outputted as it is through the second output end of the first circulator; When the control circuit does not respond, the first gas discharge tube does not discharge, and the input microwave long pulse enters the second circulator through the first output end of the first circulator; the short-circuit piston in the HT arm is adjusted to minimize the power entering the HT arm, and the rest of the power enters the resonant cavity; when the second gas discharge tube does not discharge, the short-circuit surface position is the short-circuit piston surface, the coupling coefficient between the resonant cavity and the output end of the HT branch is large, and the system is in the energy storage stage; when the second gas discharge tube discharges to form a short-circuit surface, the coupling coefficient between the resonant cavity and the output end of the HT branch becomes smaller, the energy in the resonant cavity is rapidly released, compressed into a narrow pulse, and finally output through the second output end of the second circulator.

3. A switchable high-power microwave active pulse compression system as claimed in claim 2, characterized in that: Said The short-circuit position of the second gas discharge tube changes by 1 / 4λ before and after discharge g , realize impedance transformation, thereby changing the resonant cavity coupling coefficient, where λ g Indicates the operating wavelength.

Images