A high-power microwave arcing fast protection circuit

Abstract

This invention discloses a high-power microwave arcing rapid protection circuit, including a directional coupler C1, a detector D1, and a protection output circuit. The directional coupler C1 is positioned between the output window of the vacuum device and the transmission feed line to monitor the reflected power in real time. The measurement port of the directional coupler C1 is connected to the detector D1, which converts the real-time monitored microwave reflected power into a voltage signal. The output terminal of the detector D1 is connected to the protection output circuit. The protection output circuit determines whether to output a protection signal to the interlocking control system based on the voltage signal output by the detector D1. The interlocking control system then executes the protection action based on the protection signal. This invention achieves reliable monitoring and rapid protection against high-power microwave arcing by monitoring power reflection to determine whether to execute protection, thereby preventing the output window from operating in a continuous high-power reflection state and protecting the output window.

Description

Technical Field

[0001] This utility model relates to the field of high-power microwave technology, and in particular to a high-power microwave arcing rapid protection circuit. Background Technology

[0002] High-power microwaves are a type of strong electromagnetic pulse, widely used in particle accelerators, medical, scientific research, and military fields. In the military field, they are commonly used in equipment such as radar, as exemplified by a high-repetition-rate phased array high-power microwave system (patent application number 202411762589.9). The devices that generate or amplify high-power microwaves are primarily vacuum electronic devices and relativistic devices, with conventional devices mainly being vacuum electronic devices, including klystrons, magnetrons, and traveling wave tubes.

[0003] Electro-vacuum devices, due to their operating principles, require an ultra-high vacuum environment (10⁻⁶ m² / 40⁻¹²) to generate or amplify high-power microwave signals. -7 High-power microwave transmission lines rarely achieve this level of vacuum (above Pa), so vacuum electronic devices require isolated output sealed windows to ensure ultra-high vacuum within the tube. These output windows are typically made of special ceramic materials. When high-power microwaves arc in the transmission line, they generate significant power reflected back to the output window. If this occurs repeatedly, it can easily puncture the ceramic body of the output window, damaging the vacuum electronic device. To prevent this risk, it is necessary to avoid continuous bombardment of the ceramic window by this reflected power.

[0004] Currently, there are two main protection methods commonly used: First, a high-power isolator is added: This method involves adding a high-power isolator (also called a circulator) after the output window of the vacuum electronic device to directly absorb the power reflected from the high-power microwave arcing in the subsequent feed line. This high-power isolator can typically reduce the reflected power by more than 30dB, thus effectively protecting the output window. The advantage of this method is its excellent protection effect, essentially eliminating the possibility of reflected power damaging the output window.

[0005] Its disadvantages are also obvious. First, the peak power of its supporting high-power microwave system is relatively low, generally only reaching 3-5MW (with frequency band differences), due to current technological and material limitations. Thus, this protection method cannot be used for high-power microwave systems above 5MW. Second, high-power isolators are expensive, ranging in price from tens of thousands to hundreds of thousands of yuan.

[0006] Another commonly used method is VSWR protection: This method mainly involves adding two directional couplers after the output window of the vacuum electronic device to monitor the output forward power and reflected power in real time. The two signals are connected to a standing wave ratio (SWR) monitor. The SWR monitor measures the input-output SWR, and when the ratio exceeds the set protection value, an alarm signal is sent to the control system to achieve protection.

[0007] The advantage of this method is that it can make up for the shortcomings of method 1, and it is suitable for both high peak power systems and low peak power systems.

[0008] The disadvantages are high cost; VSWR monitors are expensive, and the price increases with the frequency, starting at tens of thousands of yuan and reaching hundreds of thousands of yuan in the high-frequency range. Additionally, their response speed is relatively slow, and their protection effect is poor at high-power microwave repetition frequencies. Utility Model Content

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a rapid protection against high-power microwave arcing. This allows for reliable monitoring and rapid protection against high-power microwave arcing. By monitoring the power reflection value, the invention determines whether to execute protection, thereby preventing the output window from operating in a high-power reflection state and protecting the output window.

[0010] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A high-power microwave arcing rapid protection circuit includes a directional coupler C1, a detector D1, and a protection output circuit. The directional coupler C1 is disposed between the output window of the vacuum device and the transmission feed line to monitor the reflected power in real time. The measurement port of the directional coupler C1 is connected to the detector D1, which converts the real-time monitored microwave reflected power into a voltage signal. The output terminal of the detector D1 is connected to the protection output circuit. The protection output circuit determines whether to output a protection signal to the interlocking control system based on the voltage signal output by the detector D1. The interlocking control system executes protection actions based on the protection signal.

[0011] The protection output circuit includes a peak sampling circuit and a fast comparator N1. The input of the peak sampling circuit is connected to the output of the detector D1 for real-time sampling of the voltage signal output by the detector D1. The output of the peak sampling circuit is connected to the first input of the fast comparator N1, and the second input of the fast comparator N1 is connected to the reference source P1. The fast comparator N1 outputs a corresponding protection signal based on the comparison result of the input signals at the first and second inputs.

[0012] The directional coupler C1 is a microwave coupler that matches the feeder interface of a high-power microwave system.

[0013] The detector D1 is a crystal detector matched to the frequency band of a high-power microwave system. The reference source P1 is used to generate a reference voltage, and the reference voltage generated by the reference source P1 can be amplitude-adjusted by a potentiometer and then output as an adjustable reference voltage to the second input terminal of the fast comparator N1.

[0014] The output of the fast comparator N1 is connected to the alarm unit, which is used to drive the alarm unit to issue an alarm reminder signal through the protection signal.

[0015] The advantages of this invention are: it achieves reliable monitoring and rapid protection against high-power microwave arcing. By monitoring the power reflection value, it determines whether to activate protection, thereby preventing the output window from operating in a high-power reflection state and protecting the output window. Using this circuit to protect against high-power microwave arcing has the following significant advantages: The protection circuit is simple, a pure hardware circuit, and offers fast protection speed and good protection effect. All components used are conventional, easy to procure, and inexpensive; Fast protection circuits can be integrated into small printed circuit boards, and their input / output interfaces are rich and flexible, such as SMA, N, and BNC, which can be flexibly converted according to the needs of the supporting system. Attached Figure Description

[0016] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings: Figure 1 This is a schematic diagram of the high-power microwave arcing rapid protection circuit of this utility model; Figure 2 This is a schematic diagram of the protection output circuit of this utility model. Detailed Implementation

[0017] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and the description of the preferred embodiments.

[0018] This embodiment mainly implements a rapid monitoring and protection circuit for high-power microwave arcing. By monitoring the feedback microwave signal and using a comparison reference, a corresponding protection signal is issued. The protection signal is used to achieve interlock protection, preventing the system from running continuously when the reflected power is too high. When the reflected power is too high, the interlock protection action stops the system from working and issues an alarm signal to protect against high-power microwave arcing.

[0019] A high-power microwave arcing rapid protection circuit in this embodiment includes a directional coupler C1, a detector D1, and a protection output circuit. The directional coupler C1 is disposed between the output window of the vacuum device and the transmission feeder to monitor the reflected power in real time. The measurement port of the directional coupler C1 is connected to the detector D1, which converts the real-time monitored microwave reflected power into a voltage signal. The output terminal of the detector D1 is connected to the protection output circuit. The protection output circuit determines whether to output a protection signal to the interlocking control system based on the voltage signal output by the detector D1. The interlocking control system executes protection actions based on the protection signal.

[0020] The interlocking protection system is part of the control system of the high-power microwave system. It is mainly composed of a programmable logic controller (PLC). When the interlocking protection system receives a fire protection signal, it will directly shut down the output of the high-power microwave system within microseconds, thereby preventing excessive reflected power from continuously bombarding the ceramic window and thus achieving rapid protection of the ceramic sealed window.

[0021] The protection output circuit includes a peak sampling circuit and a fast comparator N1. The input of the peak sampling circuit is connected to the output of detector D1 to sample the voltage signal output by detector D1 in real time. The output of the peak sampling circuit is connected to the first input of fast comparator N1, and the second input of fast comparator N1 is connected to a reference source P1. Fast comparator N1 outputs the corresponding protection signal based on the comparison result of the input signals at the first and second inputs. The peak sampling quantity can be sampled using a resistor divider or a mature AD sampling circuit to acquire the corresponding voltage signal. Fast comparator N1 uses a high-speed analog or digital comparator to achieve rapid comparison of the input voltage signals at the first and second inputs, and outputs a high-level or low-level signal based on the comparison result of the two voltages. Low level and high level represent protection execution and protection non-execution, respectively. The interlocking control system uses this acquired signal to control the operating status of the high-power microwave system, such as controlling the microwave system to stop working through the interlocking control system. Reference source P1 generates a reference voltage. This reference voltage, after amplitude adjustment by a potentiometer, is output to the second input terminal of fast comparator N1. Alternatively, reference source P1 can be a high-precision DC voltage source. The DC voltage source output, after passing through a series resistor and potentiometer, outputs a reference voltage to the fast comparator. Adjusting the potentiometer value allows for adjustment of the reference voltage output to the fast comparator. For example, the reference voltage source can be grounded via a series resistor and potentiometer, with the reference voltage output terminal connected to the comparator between the resistor and potentiometer. Adjusting the reference voltage allows for adjustment of the reference voltage output to the fast comparator, thus expanding the circuit's applicability and meeting different protection threshold requirements.

[0022] In this embodiment, the directional coupler C1 is a microwave coupler matched to the feeder interface of the high-power microwave system. The detector D1 is a crystal detector matched to the frequency band of the high-power microwave system. The high-power microwave system refers to an electrovacuum device system formed by the output window through the transmission feeder. Since this protection circuit is applied to this system, the selected parameters should meet its frequency and interface requirements.

[0023] In a preferred embodiment of this application, the output protection signal is used not only to drive the interlocking control system to achieve protection actions, but also to control the alarm signal to issue alarm information. The output of the fast comparator N1, corresponding to the alarm action, is connected to the alarm unit to drive the alarm unit to issue an alarm reminder signal via the protection signal. The alarm unit is a fast optocoupler or a high-speed relay, which can upload the alarm signal to the interlocking protection system within a microsecond time range. The interlocking protection system will also shut down the output of the high-power microwave system within a microsecond time range, thereby achieving rapid protection.

[0024] This embodiment of a high-power microwave arcing rapid protection device centers on a directional coupler placed behind the output window of an electro-vacuum device for real-time monitoring of reflected power. A crystal detector is connected to the measurement port of the directional coupler to convert the real-time measured microwave reflected power into a voltage signal. This voltage signal is then sent to a protection output circuit, which can be set with a protection threshold. When the amplitude of the voltage signal converted from reflected power exceeds the set threshold, the protection circuit quickly activates and directly interlocks the control system, executing the protection strategy.

[0025] The aforementioned directional couplers are conventional microwave couplers (ring, cross, etc.) that match the system feeder interface (flange, coaxial, etc.). The aforementioned detectors are conventional crystal detectors that meet the system's frequency band requirements; they are low in cost and readily available. The aforementioned protection output circuit mainly consists of a reference source, a peak sampling circuit, a fast comparator, and a fault interlocking circuit. The electronic components are all conventional components, which are low in cost and readily available. like Figure 1 , 2 As shown, pin 1 of directional coupler C1 is connected to pin 2 of the output window of the vacuum tube, and pin 2 of C1 is connected to the transmission feeder; pin 3 of C1 is connected to pin 1 of detector D1, and pin 2 of detector D1 is connected to pin 1 of the peak sampling circuit S1 in the fast protection circuit; pin 2 of the peak sampling circuit S1 is connected to pin 1 of the fast comparator N1, reference source P1 is connected to pin 2 of N1, pin 3 of N1 is connected to pin 1 of the protection output circuit O1; pin 2 of the protection output circuit O1 is directly connected to the control system interlocking circuit via a cable.

[0026] In the above circuit, the directional coupler C1 and the detector D1 constitute the high-power microwave reflected power sampling and conversion function; the peak sampling circuit S1, the reference source P1, the fast comparator N1 and the protection output circuit O1 constitute the fast protection circuit to complete the fast protection function.

[0027] In this invention, a directional coupler C1 is first used to couple and attenuate the high-power microwaves reflected from the transmission feeder into small-signal microwaves. Then, a detector D1 converts the small-signal microwaves into a voltage signal, which is then sent to the fast protection circuit. The peak sampling circuit S1 in the fast protection circuit samples the voltage signal converted from the reflected wave in real time and sends it to terminal 1 of the fast comparator N1. The reference source P1 is mainly responsible for powering the fast protection circuit and generating and adjusting the reference voltage. The reference DC voltage it generates is sent to terminal 2 of the fast comparator N1. This DC voltage can be adjusted by a potentiometer to change the protection action conditions. The fast comparator N1 compares the voltage amplitudes at terminals 1 and 2. When the voltage at terminal 1 is greater than the voltage at terminal 2, pin 3 of the comparator activates, starting the protection output circuit O1 and outputting a protection signal to the control system for interlocking. Because the protection circuit is simple, using hardware circuitry and a fast comparator, its protection time can reach within 1μs, thus achieving fast protection. Furthermore, due to its fast protection speed, this invention is also suitable for protection applications in high repetition frequency systems.

[0028] In this invention, the directional coupler is a conventional microwave directional coupler (ring, cross, etc.) with matching system feeder interface (flange, coaxial, etc.), which is an off-the-shelf product; the detector is a conventional microwave detector with no special performance requirements, only needing to ensure that it is in the same frequency band as the high-power microwave signal, and is inexpensive and easy to procure; the fast protection circuit is simple in form, and all components used are conventional electronic components, which are inexpensive and readily available.

[0029] Considering standardization, modularity, and versatility, the fast protection circuit is designed as a small printed circuit board. Its input / output interface is packaged to be compatible with various RF interfaces such as SMA, BNC, and N-type, allowing for flexible interface replacement according to system requirements. Simultaneously, a metal shielding box is incorporated to enhance the electromagnetic compatibility and aesthetics of the fast protection circuit.

[0030] The protection scheme in this embodiment is simple and effective, and all the components used are conventional low-value components. Therefore, its cost is significantly reduced compared to traditional protection methods, with a reduction rate of tens or even hundreds of times.

[0031] Obviously, the specific implementation of this invention is not limited to the above-described methods. Any non-substantial improvements made using the inventive concept and technical solution of this invention are within the protection scope of this invention.

Claims

1. A high power microwave arcing fast protection circuit, characterized by: It includes a directional coupler C1, a detector D1, and a protection output circuit; the directional coupler C1 is located between the output window of the vacuum device and the transmission feeder to monitor the reflected power in real time. The measurement port of the directional coupler C1 is connected to the detector D1. The detector D1 is used to convert the real-time monitored microwave reflection power into a voltage signal. The output terminal of the detector D1 is connected to the protection output circuit. The protection output circuit determines whether to output a protection signal to the interlocking control system based on the voltage signal output by the detector D1. The interlocking control system executes protection actions based on the protection signal.

2. A high power microwave arcing fast protection circuit as claimed in claim 1, characterized in that: The protection output circuit includes a peak sampling circuit and a fast comparator N1. The input of the peak sampling circuit is connected to the output of the detector D1 for real-time sampling of the voltage signal output by the detector D1. The output of the peak sampling circuit is connected to the first input of the fast comparator N1, and the second input of the fast comparator N1 is connected to the reference source P1. The fast comparator N1 outputs a corresponding protection signal based on the comparison result of the input signals at the first and second inputs.

3. A high power microwave arcing fast protection circuit as claimed in claim 1 or 2, characterized in that: The directional coupler C1 is a microwave coupler that matches the feeder interface of a high-power microwave system.

4. A high-power microwave arcing fast protection circuit according to claim 1 or 2, characterized in that: The detector D1 is a crystal detector that matches the frequency band of a high-power microwave system.

5. A high-power microwave arcing rapid protection circuit as described in claim 2, characterized in that: The reference source P1 is used to generate a reference voltage. The reference voltage generated by the reference source P1 is adjusted by a potentiometer and then output to the second input terminal of the fast comparator N1.

6. The high-power microwave arcing rapid protection circuit as described in claim 2, characterized in that: The output of the fast comparator N1 is connected to the alarm unit, which is used to drive the alarm unit to issue an alarm reminder signal through the protection signal.

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