High-power ultra-wideband plasma amplitude limiter

Abstract

The invention, which belongs to the technical field of the plasma amplitude limiter, discloses a high-power ultra-wideband plasma amplitude limiter comprising an input window, a discharge gap, an output window and an amplitude limiting module. The plasma amplitude limiter is reliable in structure, ultra-wide in band and high in power capacity, is located at the front end of a receiver, and plays a role in protecting high-power microwave attacks. The plasma amplitude limiter disclosed by the invention can bear high-power microwave attack with the highest power magnitude of 10kW in the widest frequency band range of 10GHz, and a receiving access can be quickly switched off within 10ns, so that the aim of protecting the whole communication system is fulfilled; a coaxial ultra-wideband design technology is adopted, a full-hard welding structure is adopted, the structure is stable and reliable, and the frequency band range of the plasma amplitude limiter tube covers L, S, C, X and Ku wave bands; the multi-stage pointed-cone-shaped discharge gaps are adopted, leakage power is reduced stage by stage, and therefore safe work of the amplitude limiting chip is guaranteed, and finally the plasma amplitude limiter with high bearing power and short response time is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of plasma limiters, and in particular relates to a high-power ultra-wideband plasma limiter. Background Art

[0002] Electromagnetic pulse (EMP) is a novel non-contact attack method. It irradiates an enemy's equipment with a high-power electromagnetic pulse, disrupting or damaging the electronic components within it, rendering it inoperable. This method can achieve both soft and hard kills, representing a higher level of electronic countermeasures. The radar's "front door" acts as an energy collector while transmitting the pulse, providing a crucial means for powerful EMPs to damage radar receivers. The emergence of EMP weapons has placed new demands on the design, power capacity, and response time of modern military radar's "front door" protection devices. The development of high-power, fast-response plasma limiters has become a key area of ​​recent radar technology development.

[0003] This patent describes a reliable, ultra-wideband, high-power plasma limiter located at the front end of a receiver, providing protection against high-power microwave attacks. While solid-state devices typically suffer from damage power levels of 100W to 300W, the plasma limiter can withstand high-power microwave attacks up to 10kW within a frequency band as wide as 10GHz, rapidly shutting down the receiving path within 10ns, protecting the entire communication system. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to solve the technical shortcomings of two devices, namely, low damage power of solid-state devices and long response time of gas discharge tubes, and to provide a high-power ultra-wideband plasma limiter with a power capacity of the order of 10kW, a response time of less than 10ns, and a frequency band of up to 10GHz.

[0005] The present invention adopts the following technical solutions to solve the above technical problems: A high-power ultra-wideband plasma limiter includes a front-stage TR tube and a rear-stage limiting module. The front-stage TR tube consists of an input window, an output window, and a discharge gap loaded in a coaxial line segment. The front-stage TR tube is a gas-filled microwave tube used to reduce the power to a range that the limiting module can withstand. The rear-stage limiting module further reduces the leaked power to the required level. The integrated chip is soldered to the circuit via a microstrip line.

[0006] As a further preferred embodiment of a high-power ultra-wideband plasma limiter of the present invention, the coupling window between the input window and the output window is used for vacuum sealing and also serves to connect the internal and external transmission lines; and the coupling window ceramic is made of sapphire material with high mechanical strength, strong thermal shock resistance and high power capacity per unit area.

[0007] As a further preferred embodiment of the high-power ultra-wideband plasma limiter of the present invention, the discharge gap is provided to reduce the leakage power and ignition power of the coaxial discharge tube. By reducing the distance between the inner and outer conductors of the coaxial line, the voltage between the inner and outer conductors is increased, resulting in a normal voltage discharge. That is, the electric field between the inner and outer conductors caused by the voltage ionizes the gas, generating plasma. The discharge gap adopts a multi-stage conical discharge gap.

[0008] As a further preferred embodiment of the high-power ultra-wideband plasma limiter of the present invention, a coaxial limiter low-pass filter structure comprising an input window, a discharge gap, and an output window is utilized. By varying the discharge gap dimensions, the capacitance value in the equivalent circuit is adjusted. During simulation, the structural dimensions are adjusted to achieve changes in equivalent capacitance and inductance, thereby achieving good impedance matching for the transmission line. The bandwidth is broadened by increasing the number of discharge gaps from one to four.

[0009] As a further preferred embodiment of a high-power ultra-wideband plasma limiter of the present invention, the TR tube uses Ni+63 as a radioactive source of a radioactive target source structure, which is used to provide a certain amount of electrons to the high-frequency discharge gap to ensure rapid and reliable ignition when the high-frequency pulse arrives.

[0010] As a further preferred solution of the high-power ultra-wideband plasma limiter of the present invention, the coupling window loses its original matching state due to the introduction of the coupling window dielectric plate, and if the impedance is to be kept unchanged, the size of the inner and outer conductors near the window plate is adjusted to achieve the purpose of compensation.

[0011] As a further preferred solution of the high-power ultra-wideband plasma limiter of the present invention, the input and output interface form of the coupling window is SMA-F, which is obtained through simulation calculation.

[0012] As a further preferred embodiment of a high-power ultra-wideband plasma limiter of the present invention, the plasma is conductive, that is, a path is formed between the inner and outer conductors, which is used to guide the energy from the inner conductor to the outer conductor, and then discharge it along the tube shell to the system ground wire, thereby protecting the subsequent devices.

[0013] As a further preferred solution of a high-power ultra-wideband plasma limiter of the present invention, the TR tube is designed based on the principle of a coaxial low-pass filter. The impedance matching state of the coaxial transmission line is achieved through the size of each part of the coaxial transmission line, thereby realizing the broadband design requirements.

[0014] As a further preferred embodiment of the high-power ultra-wideband plasma limiter of the present invention, the frequency of the TR tube covers L, S, C, X, and Ku bands; the gaps of the TR tube are welded by hard welding including brazing, argon arc welding, and laser welding.

[0015] As a further preferred embodiment of a high-power ultra-wideband plasma limiter of the present invention, the TR tube uses Ni+63 as a radiation source of a radioactive target source structure, and the frequency of the TR tube covers L, S, C, X, and Ku bands.

[0016] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects: 1. The present invention discloses a high-power ultra-wideband plasma limiter comprising a TR+L structure consisting of an input window, a discharge gap, an output window, and a limiter module. The front-stage TR tube is a gas-filled microwave tube that reduces the power to a range that the limiter module can withstand. The rear-stage limiter module further reduces the leakage power to the required level. The limiter module solders the integrated chip to the circuit via microstrip lines and adopts a multi-stage diaphragm-type discharge gap structure, which gradually reduces the voltage to the minimum leakage power. The smaller the gap, the lower the ignition power, the faster the response time, and the lower the leakage power. Ni+63 is coated on the surface of the conductor in the discharge gap as a radioactive target source, providing a certain amount of initial electrons to excite the gas for rapid ionization, thereby controlling the response time. 2. The present invention provides a reliable, ultra-wideband, high-power plasma limiter located at the front end of a receiver to protect against high-power microwave attacks. While the damage power of solid-state devices is generally 100W to 300W, the plasma limiter of the present invention can withstand high-power microwave attacks of up to 10kW within a frequency band as wide as 10GHz and rapidly shut down the receiving path within 10ns, thus protecting the entire communication system. 3. The high-power ultra-wideband plasma limiter provided by the present invention has been developed through extensive calculations and experiments, and has a reasonable structural design, high power handling, short response time, light weight, and high reliability. The present invention adopts coaxial ultra-wideband design technology and a fully hard-welded structure, which is stable and reliable. The frequency band range of the plasma limiter tube covers the L, S, C, X, and Ku bands. A multi-stage conical discharge gap is used to gradually reduce the leakage power, thereby ensuring the safe operation of the limiter chip, and ultimately realizing a plasma limiter with high power handling and short response time. The life test has completed more than 10,000 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the coaxial low-pass filter of the present invention; wherein a is the structure; b is the equivalent circuit; Figure 2The coupling window simulation model and calculation results of the present invention are shown in FIG. 1 , wherein a is the simulation model and b is the coupling window standing wave simulation result. Figure 3 is the discharge gap simulation model and calculation results of the present invention; wherein a is the simulation model, and is the discharge gap standing wave simulation result; Figure 4 The simulation model and calculation results of the TR tube of the present invention are shown in FIG. 1 , where a is the simulation model and b is the standing wave simulation result of the TR tube. Figure 5 This is an outline diagram of the plasma limiter of the present invention. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings: The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The present invention is described in detail below based on the drawings and preferred embodiments. The purpose and effect of the present invention will become more clear. It should be understood that the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0019] The purpose of the present invention is to address the technical shortcomings of solid-state devices, namely low damage power (on the order of hundreds of watts) and long response time (on the order of 100 ns) of gas discharge tubes, and to provide a high-power ultra-wideband plasma limiter with a power capacity of 10 kW, a response time of less than 10 ns, and a frequency band of up to 10 GHz.

[0020] The present invention adopts a multi-stage diaphragm type discharge gap structure, which reduces the voltage step by step to the minimum leakage power. The smaller the gap, the smaller the ignition power, the faster the response time, and the smaller the leakage power.

[0021] By coating the surface of the conductor in the discharge gap with Ni +63 As a radioactive target source, it provides a certain amount of initial electrons to excite the gas to quickly ionize and control the response time.

[0022] The plasma limiter is composed of components such as a coupling window, a discharge gap, and a limiting chip. The loading of each level of components will change the original matching state of the coaxial line. Therefore, when simulating the overall design of the coaxial limiter, it is necessary to achieve the broadband design requirement by performing impedance transformation on the inner and outer conductors of the coaxial line.

[0023] Coaxial cable impedance transformation sections can be either equal impedance transformation or unequal impedance transformation. Their structures can be either step-change or tapered. In a tapered transformation section, the inner and outer conductor extensions can intersect at a single point or not. In a step-change structure, the relative axial position of the inner and outer conductors must be adjusted to compensate for the step capacitance at the point of the change.

[0024] Using the coaxial type limiter low pass filter structure, the coaxial low pass filter is as follows Figure 1 As shown in the figure, a is the structure; b is the equivalent circuit; the dimensions of the inner conductors on both sides of the discharge gap are changed, and the capacitance and inductance values ​​in the equivalent circuit are adjusted to achieve a good impedance matching state of the transmission line.

[0025] The overall structure of the present invention is a TR+L structure consisting of an input window, a discharge gap, an output window, and a limiting module. The front-stage TR tube is a gas-filled microwave tube that reduces the power to a level within the limiting module's tolerance. The rear-stage limiting module further reduces the leaked power to the required level. The limiting module solders the integrated chip to the circuit via microstrip lines. The performance of the limiting module is determined by the chip's performance.

[0026] Simulation design: The TR tube consists of an input window, an output window, and a discharge gap mounted on a coaxial line. The coupling window ceramic is made of sapphire, a material with high mechanical strength, strong thermal shock resistance, and high power capacity per unit area. The discharge gap is a pointed plate-shaped structure with four stages, providing more stable discharge. The TR tube covers the L, S, C, X, and Ku bands.

[0027] Simulation design of coupling window: For high-power microwave vacuum-sealed windows, the coupling window primarily serves as a vacuum seal and also connects the internal and external transmission lines. The coupling window ceramic is made of sapphire, a material with high mechanical strength, strong thermal shock resistance, and high power capacity per unit area. The introduction of the dielectric sheet in the coupling window changes its impedance, disrupting the original matching state. To maintain a constant impedance, the dimensions of the internal and external conductors near the window must be adjusted to compensate.

[0028] The relevant dimensions of the coupling window are combined with the design of the whole tube. The input and output interface forms are SMA-F. The coupling window simulation model is obtained through simulation calculation. Figure 2 As shown in Figure 2, a is the simulation model and b is the coupling window standing wave simulation result.

[0029] Simulation design of multi-level discharge gap: The discharge gap is designed to reduce leakage power and ignition power in a coaxial discharge tube. By reducing the distance between the inner and outer conductors of the coaxial cable, the voltage between them increases, resulting in a normal voltage discharge. The electric field between the inner and outer conductors, created by the voltage, ionizes the gas, generating plasma. Because plasma is conductive, it forms a pathway between the inner and outer conductors, directing energy from the inner conductor to the outer conductor, and then dissipating it along the tube casing to the system ground, protecting subsequent devices.

[0030] The coaxial limiter low-pass filter structure includes an input window, a discharge gap, and an output window. By changing the discharge gap structure size and adjusting the capacitance value in the equivalent circuit, the structure size is adjusted during simulation to achieve a change in equivalent capacitance and inductance, thereby achieving a good impedance matching state for the transmission line. By increasing the number of discharge gaps from one to four, the bandwidth is widened. The discharge gap structure diagram is shown in the figure below. Figure 3 As shown, a is the simulation model and b is the discharge gap standing wave simulation result.

[0031] TR tube simulation design: The TR tube part consists of an input window, an output window and a discharge gap loaded in a coaxial line segment.

[0032] The TR tube simulation model and calculation results are shown in Figure 4 , the plasma limiter appearance is as follows Figure 5 As shown in the figure, the design is based on the principle of coaxial low-pass filter. The impedance matching state of the coaxial transmission line is achieved by adjusting the size of each part of the coaxial transmission line to meet the broadband design requirements.

[0033] Design of radioactive source: TR tube adopts Ni +63 As a radioactive target source structure, the radioactive source can provide a certain amount of electrons to the high-frequency discharge gap to ensure rapid and reliable ignition when the high-frequency pulse arrives. +63 The radioactive source is coated on the electrode, does not require an ignition power supply, and there is no electron bombardment, so no metal spattering and thermal effects occur.

[0034] Full hard soldering process design: One of the key measures to ensure high reliability of the limiter is the use of hard soldering. TR tubes eliminate the use of soft soldering to prevent flux from leaking into the tube and being bombarded by electrons, which would cause metal spattering. This spattered metal would form a thin film near the window, increasing tube losses and absorbing certain gases. Therefore, all joints in this project are welded using hard soldering (brazing, argon arc welding, or laser welding). Because hard soldering does not require flux and can degas at relatively high temperatures, it significantly improves the cleanliness of the tube interior, thereby achieving satisfactory repeatability and stability of tube parameters over a wide temperature range.

[0035] Exhaust process design: Pre-exhaust to remove leaking pipes and bake out impurity gases. By filling with inert gas at a certain pressure, leakage power can be reduced and response time can be shortened.

[0036] The high-power ultra-wideband plasma limiter provided by the present invention has been developed through extensive calculations and experiments, resulting in a rational structural design with high power handling, short response time, light weight, and high reliability. This invention utilizes coaxial ultra-wideband design technology and a fully brazed structure, resulting in a stable and reliable structure. The plasma limiter tube covers the L, S, C, X, and Ku bands. A multi-stage conical discharge gap is used to gradually reduce leakage power, thereby ensuring the safe operation of the limiter chip. The result is a plasma limiter with high power handling and short response time. The device has completed life tests exceeding 10,000 hours.

[0037] Those skilled in the art will understand that the above descriptions are merely preferred embodiments of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, etc. made within the spirit and principles of the invention shall be included in the scope of protection of the invention. All technical features in this embodiment may be freely combined according to actual needs.

[0038] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-power ultra-wideband plasma limiter, characterized in that: It includes a front-stage TR tube and a rear-stage limiting module. The front-stage TR tube consists of an input window, an output window and a discharge gap loaded in a coaxial line segment. The front-stage TR tube is a gas-filled microwave tube used to reduce the power to a range that the limiting module can withstand. The rear-stage limiting module further reduces the leaked power to the index requirements, and the integrated chip is welded to the circuit through a microstrip line.

2. A high-power ultra-wideband plasma limiter according to claim 1, characterized in that: The coupling window of the input window and the output window is used for vacuum sealing and also serves to connect the internal and external transmission lines; and the coupling window ceramic piece is made of sapphire material with high mechanical strength, strong heat shock resistance and large power capacity per unit area.

3. The high-power ultra-wideband plasma limiter according to claim 1, characterized in that: The discharge gap is used to reduce the leakage power and ignition power of the coaxial discharge tube. By reducing the distance between the inner and outer conductors of the coaxial line, the voltage between the inner and outer conductors is increased, which becomes a common voltage discharge, that is, the electric field between the inner and outer conductors caused by the voltage ionizes the gas to generate plasma; the discharge gap adopts a multi-stage pointed cone discharge gap.

4. A high-power ultra-wideband plasma limiter according to claim 3, characterized in that: A coaxial limiter low-pass filter structure including an input window, a discharge gap, and an output window is used. The discharge gap structure size is changed, and the capacitance value in the equivalent circuit is adjusted. During simulation, the structure size is adjusted to achieve changes in equivalent capacitance and inductance to achieve a good impedance matching state of the transmission line. The bandwidth is widened by increasing the number of discharge gaps from one level to four levels.

5. The high-power ultra-wideband plasma limiter according to claim 1, characterized in that: The TR tube adopts Ni +63 As a radioactive target source structure, the radiation source is used to provide a certain amount of electrons to the high-frequency discharge gap to ensure rapid and reliable ignition when the high-frequency pulse arrives.

6. A high-power ultra-wideband plasma limiter according to claim 2, characterized in that: Due to the introduction of the coupling window dielectric sheet, the impedance of the coupling window is changed and the original matching state is lost. If the impedance is to be kept unchanged, the size of the inner and outer conductors near the window sheet can be adjusted to achieve the purpose of compensation.

7. A high-power ultra-wideband plasma limiter according to claim 6, characterized in that: The input and output interface form of the coupling window is SMA-F, which is obtained through simulation calculation.

8. The high-power ultra-wideband plasma limiter according to claim 3, characterized in that: Plasma is conductive, that is, a path is formed between the inner and outer conductors to direct the energy from the inner conductor to the outer conductor, and then discharge it along the tube shell to the system ground wire, thereby protecting the subsequent devices.

9. The high-power ultra-wideband plasma limiter according to claim 3, characterized in that: The TR tube is designed based on the principle of coaxial low-pass filter. Through the size of each part of the coaxial transmission line, the impedance matching state of the coaxial transmission line is achieved to realize the broadband design requirements.

10. The high-power ultra-wideband plasma limiter according to claim 5, characterized in that: The frequency of the TR tube covers L, S, C, X, and Ku bands; the gaps of the TR tube are welded by hard welding including brazing, argon arc welding, and laser welding.

Images