Signal wall box with strong electromagnetic pulse combination protection and high shielding effectiveness

Abstract

The invention relates to a signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness, which belongs to the field of shielding square cabins of electronic equipment and comprises a shell, an out-cabin panel, an in-cabin panel and a filter. The peripheral shell wall of the shell penetrates through a cabin plate of the square cabin, and an outer cabin panel and an inner cabin panel are installed at the outer end and the inner end of the shell respectively. A plurality of connector sockets are arranged on the out-cabin panel and the in-cabin panel in a one-to-one correspondence mode, and a signal interface is formed by a group of corresponding connector sockets. The plurality of filters are installed in the shell, each signal interface corresponds to one corresponding filter, and the filters are connected in series in a signal loop of a group of connector sockets. The filter comprises a combined filter, a radio frequency protection filter and a short wave protection filter. The signal wall box has lightning protection, high-altitude nuclear explosion electromagnetic pulse protection and high shielding effectiveness at the same time, and provides reliable protection for a signal window of an electronic equipment shielding square cabin in a strong electromagnetic pulse environment.

Description

Technical Field

[0001] The present invention belongs to the field of electronic equipment shielding cabins, and specifically relates to a signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness, wherein the strong electromagnetic pulse combined protection includes lightning (LEMP) protection and high-altitude nuclear electromagnetic pulse (HEMP) protection. Background Art

[0002] Electronic equipment shielding shelters are widely used mobile military facilities, offering advantages such as rapid mobility and high shielding effectiveness. During operation, electronic shelters must withstand a variety of complex strong electromagnetic pulse environments, including lightning strikes (LEMP), high-altitude nuclear electromagnetic pulses (HEMP), and high-power microwaves (narrowband HPM-NS and ultra-wideband HPM-UWB). Lightning is a natural electromagnetic phenomenon, while the others are man-made. Strong electromagnetic pulses can couple very high energy into the shelter through antennas, cables, holes, and gaps. These pulses, with their high voltage, high current, and wide bandwidth, can cause severe interference to the equipment and components within the shelter, rendering the system inoperable or even causing permanent damage to components. Therefore, they must be suppressed.

[0003] A typical high-altitude nuclear electromagnetic pulse (HEMP) has a rising edge time of approximately 10 nanoseconds and a pulse width of 500 nanoseconds. Its peak field strength can reach 50 kV / m, with a range of several thousand kilometers. Its frequency range can range from very low frequencies to hundreds of megahertz, and its energy is concentrated within the common radio frequency range, posing a serious threat to electronic and electrical equipment. When operating in the field, shielded shelters are highly susceptible to lightning damage (usually induced lightning) in the event of thunderstorms. Lightning is extremely powerful, making the consequences of damage even more severe.

[0004] The signal windows of shielded cabins handle a wide variety of signals with vastly different transmission rates. This results in significant line-to-line coupling, necessitating filtering of each signal channel based on transmission rate to ensure the wide bandwidth and high efficiency required by the shielded cabin. The signal window cables are long, multi-core, operate at low voltage, and have minimal overload capacity. Therefore, the strong electromagnetic pulse energy coupled into the signal windows can easily damage or even burn the internal circuitry.

[0005] Existing signal lightning protection products only protect against lightning pulses and cannot effectively and reliably protect against high-altitude nuclear electromagnetic pulses (HEMP). Electromagnetic interference (EMI) filters for each signal channel are also selected and installed based on the characteristics of the signal channel and used independently.

[0006] In order to ensure that the shielded cabin can work normally, a multifunctional combined signal wall box with high-altitude nuclear explosion electromagnetic pulse protection and lightning protection, as well as a wide screen band and high screen efficiency, is urgently needed to protect the signal window of the cabin. Summary of the Invention

[0007] Technical issues to be solved:

[0008] In order to avoid the shortcomings of the existing technology, the present invention provides a signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness, which also has lightning protection, high-altitude nuclear explosion electromagnetic pulse protection and high shielding effectiveness. In a strong electromagnetic pulse environment, it provides reliable protection for the signal window of the electronic equipment shielding cabin, realizes the transmission of information inside and outside the cabin, and meets the requirements of wide bandwidth and high shielding efficiency of the shielding cabin.

[0009] The technical solution of the present invention is: a signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness, comprising a shell, an outer panel, an inner panel and a filter;

[0010] The shell is closed at its periphery and open at both ends, and its periphery wall penetrates the cabin board of the square cabin; the outer panel and the inner panel are respectively installed at the outer and inner ends of the shell, and the two open ends are correspondingly closed; the outer panel and the inner panel are respectively provided with a plurality of connector sockets, and a corresponding group of connector sockets forms a signal interface; a plurality of filters are installed in the shell, and each signal interface corresponds to a corresponding filter, and the filters are connected in series in the signal circuit of a group of connector sockets;

[0011] The filter includes a combined filter, a radio frequency protection filter and a shortwave protection filter; the combined filter is used for lightning protection, HEMP protection and EMI filtering of the low-pass signal interface, the radio frequency protection filter is used for lightning protection of the microwave radio frequency interface, and the shortwave protection filter is used for lightning protection, HEMP protection and EMI filtering of the shortwave signal interface.

[0012] A further technical solution of the present invention is: a mounting flange is provided on the circumference of the shell located outside the square cabin, and the mounting flange is provided with double rows of mounting holes that are staggered and evenly distributed, which are used to be fixedly connected to the outer wall of the square cabin panel by screws; mounting surfaces are provided at both open ends of the shell, which are used to respectively install the outer panel and the inner panel by screws; a low-impedance conductive shielding material is padded between the outer panel and the outer end mounting surface of the shell, and a low-impedance conductive shielding material is padded between the inner panel and the inner end mounting surface of the shell.

[0013] A further technical solution of the present invention is: the combined filter internally includes a front-stage protection circuit and a rear-stage EMI filter circuit, the front-stage protection circuit is a combined protection circuit of LEMP protection and HEMP protection; the EMI filter circuit is connected in series to the main signal transmission loop; the input end of the front-stage protection circuit is connected to the main signal transmission loop at the front end of the EMI filter circuit, and its output end is grounded;

[0014] The front-stage protection circuit includes a transient protection device, which is a varistor or a gas discharge tube.

[0015] A further technical solution of the present invention is: the combined filter through-wall lead-type filter includes a filter housing, the internal cavity of the filter housing is divided into a front compartment and a rear compartment by a partition, the front-stage protection circuit is installed in the front compartment, located at the front end of the internal circuit of the combined filter, and the EMI filtering circuit is installed in the front compartment and the rear compartment; a through-hole capacitor is installed on the partition for electromagnetic isolation of the filter input / output; the front compartment is sealed by a front cover plate, and the rear compartment is sealed by a rear cover plate; the outer end surface of the filter housing facing away from the cover plate is its mounting surface, and the mounting surface is covered with conductive material for grounding; a hollow screw is provided on the mounting surface of the filter housing located at the rear compartment for passing cables and installing the combined filter; the input end cable of the combined filter is electrically connected to the connector socket of the panel outside the cabin, and its output end cable is electrically connected to the connector socket of the panel inside the cabin.

[0016] A further technical solution of the present invention is that the filter housing and the front and rear cover plates are made of low-carbon steel sheet metal, with the surface nickel-plated, and have comprehensive shielding and grounding properties.

[0017] A further technical solution of the present invention is: the shortwave protection filter adopts the same filter housing structure as the combined filter, and the internal circuit is the same as the internal circuit of the combined filter. The difference is that two radio frequency sockets are coaxially provided at both ends of the filter housing of the shortwave protection filter, serving as the input end and output end of the internal circuit of the shortwave protection filter respectively; the radio frequency socket at the input end of the shortwave protection filter is simultaneously installed in conjunction with the outer panel of the cabin and serves as the connector socket of the outer panel; the radio frequency socket at the output end of the shortwave protection filter is simultaneously installed in conjunction with the inner panel of the cabin and serves as the connector socket of the inner panel; the shortwave protection filter is used in conjunction with an external antenna tuner filter.

[0018] A further technical solution of the present invention is: the radio frequency protection filter is a microwave radio frequency lightning arrester.

[0019] A further technical solution of the present invention is: when the combined filter is installed in the wall box, a filter mounting plate is fixed inside the shell, and the filter mounting plate is located between the outer panel and the inner panel, electromagnetically isolating the inner and outer ends of the wall box; the combined filter is installed on both sides of the filter mounting plate; at this time, the wall box forms three layers of isolation, including isolation of the filter mounting plate, isolation of the outer panel and isolation of the inner panel.

[0020] A further technical solution of the present invention is: when the shortwave protection filter and the radio frequency protection filter are installed in the wall box, the wall box forms two layers of isolation, including isolation of the outer panel and isolation of the inner panel.

[0021] A further technical solution of the present invention is: the low-pass signal interface includes a level signal, a telephone line, a communication serial port, and an RJ45 network port.

[0022] Beneficial effects

[0023] The present invention has the following advantages: The invention selects a filter based on the transmission characteristics of each interface in the shielded shelter signal transfer window, and combines it with a wall box housing with high electromagnetic isolation to produce an integrated wall box. This wall box is assembled in the shielded shelter signal transfer window and simultaneously provides lightning (LEMP) protection, high-altitude nuclear electromagnetic pulse (HEMP) protection, and EMI filtering / shielding functions, enabling information transmission inside and outside the shelter. Furthermore, the invention is compact, lightweight, and has good maintainability and environmental adaptability.

[0024] The present invention realizes an integrated design of filtering and shielding. The wall box shell of the present invention is formed by sheet metal bending and continuous welding technology, and has a high degree of electromagnetic isolation outside the cabin / inside the cabin; the combined filter adopts an input / output isolated shielding structure to filter all signal cables, and the filter is made into a module separately, which cooperates with the shielding structure of the wall box shell to meet the high shielding efficiency requirements of the square cabin.

[0025] The present invention realizes a modular design, and each signal transfer window is matched with a signal wall box (each signal transfer window needs to transfer multiple signals). According to the characteristics of each signal interface, a corresponding filter is designed and installed, that is, one group of corresponding connector sockets corresponds to one filter. The functional division is clear, the installation is convenient, and the maintainability of the equipment is greatly improved.

[0026] The present invention achieves a multi-functional combination: Given the inherent transmission impedance and other characteristics of the low-pass signal, its induced lightning coupling energy is low. Therefore, the lightning protection circuit and the HEMP protection circuit are combined into one, giving the combined protection circuit both protection capabilities and simplifying the circuit. Furthermore, given the wide operating frequency band and high transmission rate of the low-pass signal interface, a matching filter circuit is designed based on the cutoff frequencies of different signals while ensuring signal integrity. Furthermore, to address the strong mutual coupling caused by the varying cutoff frequencies of different signal interfaces, electromagnetic isolation measures are adopted to achieve the high shielding efficiency of the cabin. The EMI filter circuit is matched with the protection circuit, ensuring timely and reliable protection activation and lower protection voltage. The signal interface achieves a combination of electromagnetic pulse protection and steady-state filtering, simultaneously possessing the multiple functions of lightning protection, HEMP protection, and EMI filtering. For microwave radio frequency interfaces operating at frequencies far above the primary energy distribution band of HEMP electromagnetic pulses, the antenna's frequency-selective characteristics result in extremely low coupling (almost zero). The transmission cable uses coaxial cables, eliminating field-line coupling, so lightning protection can be implemented at the cabin entrance window. Therefore, the present invention can partition the signal interfaces requiring three-layer isolation and two-layer isolation in the same wall box to achieve partitioned installation and functional division. The signal interfaces requiring three-layer isolation are placed in one area, and the signals requiring two-layer isolation are placed in one area.

[0027] The wall box shell is made of stainless steel with good processing performance and strong environmental adaptability, and is made by continuous welding; the filter shell inside the wall box is made of steel plate sheet metal processing and nickel-plated on the surface, with excellent shielding and grounding comprehensive performance; multiple measures ensure that the wall box has good environmental adaptability and can meet the normal operation of the container vehicle in various environments (such as humidity, heat, impact, vibration, mold, salt spray, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the internal circuit of the combined filter in the present invention;

[0029] Figure 2 This is a diagram of the protection principle of the shortwave radio receiving channel;

[0030] Figure 3 This is the schematic diagram of microwave interface protection;

[0031] Figure 4 This is the schematic diagram of the low-pass signal interface assembly in the signal wall box;

[0032] Figure 5 This is the schematic diagram of the microwave interface assembly in the signal wall box;

[0033] Figure 6 This is the assembly schematic diagram of the shortwave protection filter in the signal wall box;

[0034] Figure 7This is the assembly structure diagram of the signal wall box and multiple combined filters inside;

[0035] Figure 8 Schematic diagram of the shell composition of the combined filter;

[0036] Figure 9 The figure is a schematic diagram of the appearance structure of the short-wave protection filter, where (a) is the left view, (b) is the main view, and (c) is the right view;

[0037] Figure 10 This is a structural diagram of the signal wall box, showing its exterior panel side;

[0038] Figure 11 This is a structural diagram of the signal wall box, showing the panel side inside the cabin.

[0039] Explanation of the accompanying drawings: 1. Shell, 101. Mounting flange, 102. Filter mounting plate, 2. External panel, 3. Internal panel, 4. Cabin panel, 5. Connector socket, 6. Combined filter, 601. Pre-stage protection circuit, 602. EMI filtering circuit, 603. Filter shell, 604. Partition, 605. Feedthrough capacitor, 606. Front cover, 607. Rear cover, 608. Hollow screw, 7. RF protection filter, 8. Shortwave protection filter, 81. Input RF socket of shortwave protection filter, 82. Output RF socket of shortwave protection filter, 9. Antenna tuner filter, 10. Cabin, 11 Antenna, 12. Antenna tuner, 13. Shortwave radio, 14. Microwave equipment, 15. Wall box, 16. Input cable, 17. Output cable, 18. Microwave cable. DETAILED DESCRIPTION

[0040] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0042] See Figure 4This embodiment provides a signal wall box with lightning (LEMP) protection, high-altitude nuclear electromagnetic pulse (HEMP) protection and high shielding effectiveness. The signal wall box includes four main structures: a shell 1, an outer panel 2, an inner panel 3 and a filter.

[0043] The shell 1 is a metal shell formed from stainless steel sheet metal, closed at its perimeter and open at both ends. All joints are continuously welded. The perimeter of the shell 1 penetrates the shelter's decking 4 and fits tightly against it. A mounting flange 101 is provided on the perimeter of the shell 1 outside the shelter. This flange is equipped with two rows of evenly spaced mounting holes, which are fixed to the outer wall of the shelter's decking 4 using multiple screws.

[0044] The exterior panel 2 and interior panel 3 are mounted on the exterior and interior ends of the housing 1, respectively. The exterior panel 2 is screwed to the exposed end of the housing 1 outside the cabin, sealing the exterior port. The interior panel 3 is screwed to the exposed end of the housing 1 inside the cabin, sealing the interior port. The mating surfaces between the exterior panel 2 and the housing 1, and the mating surfaces between the interior panel 3 and the housing 1, are padded with low-impedance conductive shielding material, providing excellent conductivity and deformation tolerance. Multiple connector sockets 5 are provided on each of the exterior and interior panels 2 and 3, correspondingly forming a signal interface. The connector sockets 5 themselves exhibit electromagnetic shielding properties. This provides electromagnetic isolation between the exterior panel 2 and the interior panel 3.

[0045] The double row of mounting holes on the mounting flange 101 of the housing 1 features extremely close spacing between the screws and holes. The mating surface between the outer wall of the cabin 4 and the mounting flange 101 is padded with low-impedance conductive shielding material. The screw connection between the housing 1 and the cabin 4 not only securely attaches the wall box to the outer wall of the cabin 4 but also provides a high degree of electromagnetic isolation between the inside and outside of the cabin.

[0046] Multiple filters are installed within the housing 1, one for each signal interface. These filters are connected in series to the signal loop of a set of connector sockets 5. The connector sockets 5, mounted on the exterior and interior panels 2 and 3, are designed for quick plugging and unplugging with cable connectors located outside and inside the cabin, respectively.

[0047] The filter includes a combined filter 6, a radio frequency protection filter 7 and a shortwave protection filter 8. The combined filter 6 is used for lightning protection, HEMP protection and EMI filtering of the low-pass signal interface, the radio frequency protection filter 7 is used for lightning protection of the microwave radio frequency interface, and the shortwave protection filter 8 is used for lightning protection, HEMP protection and EMI filtering of the shortwave signal interface. The shortwave protection filter 8 is used in conjunction with the antenna tuner filter 9 provided by the external antenna tuner.

[0048] For details, see Figure 1 、 4For low-pass signal interfaces, including level signals, telephone lines, serial communication ports, and RJ45 network ports, a combination filter 6 is used. This combination filter 6 is a through-the-wall lead filter, comprising a filter housing 603 and an internal protective filter circuit. It provides multiple functions, including lightning protection, HEMP protection, and EMI filtering. It is assembled to the filter mounting plate 102 in the wall box via its own hollow screw 608 (with a waveguide inside).

[0049] The input cable 16 of the combined filter 6 is electrically connected to the connector socket 5 of the exterior panel 2, and the output cable 17 is electrically connected to the connector socket 5 of the interior panel 3. It should be noted that when the combined filter 6 is installed in the wall box, a filter mounting plate 102 is fixed inside the housing 1. This plate is located between the exterior panel 2 and the interior panel 3, electromagnetically isolating the interior and exterior ends of the wall box. With the combined filter 6 mounted on both sides of the plate 102, the wall box forms a three-layer isolation structure: a first layer of isolation from the filter mounting plate 102, a second layer of isolation from the exterior panel 2, and a third layer of isolation from the interior panel 3.

[0050] See Figure 1 、 4 8. The internal cavity of the filter housing 603 is divided into a front compartment and a rear compartment by a partition 604. The internal protection filter circuit of the combined filter 6 is installed in the front compartment and the rear compartment. Figure 1 As shown, the internal protection filter circuit of the combined filter 6 includes a pre-stage protection circuit 601 and a post-stage EMI filter circuit 602. The pre-stage protection circuit is a combination of LEMP protection and HEMP protection. EMI filter circuit 602 is connected in series to the main signal transmission loop. The input end of pre-stage protection circuit 601 is incorporated into the main signal transmission loop, and its output end is grounded.

[0051] The combined filter 6 consists of a LEMP and HEMP combined protection circuit and an EMI filter circuit. In the absence of a strong electromagnetic pulse, the LEMP and HEMP combined protection circuit is open-circuited. The EMI filter circuit is connected in series within the loop, providing excellent filtering performance and meeting the cabin's electromagnetic compatibility requirements for both conduction and radiation (e.g., shielding effectiveness).

[0052] When a strong electromagnetic pulse strikes, the combined LEMP and HEMP protection circuit responds, bypassing the pulse current to the ground, thereby protecting downstream equipment and components. Within the LEMP and HEMP distribution frequency bands, the impedance characteristics of the EMI filter circuit match those of the combined LEMP and HEMP protection circuit, making the circuit's response more timely and reliable, ensuring effective protection.

[0053] The front-stage protection circuit 601 is assembled at the front end of the entire circuit and is located in the front cabin. A through-hole capacitor 605 is installed on the partition 604 for electromagnetic isolation of the input / output of the combined filter. The front cabin and the rear cabin have inductors and capacitors with different frequency characteristics, and together with the through-hole capacitor 605, they form a steady-state EMI filter circuit 602. Signal filter technology is very mature and reliable. It is selected and assembled according to the characteristics of the signal channel and will not be described in detail here. The EMI filter circuit has excellent broadband filtering performance while ensuring signal integrity, and has a delay on the LEMP and HEMP pulse currents coupled by the cable, which can make the LEMP and HEMP combined protection circuit respond more reliably and start up.

[0054] The front cabin is sealed and covered by the front cover plate 606, and the rear cabin is sealed and covered by the rear cover plate 607. The outer end surface of the filter housing 603 facing away from the two cover plates is its mounting surface. The mounting surface of the filter housing 603 is covered with conductive material and grounded with low impedance to ensure that the topological flow of pulse current and filter current discharge is on the outer surface of the cabin wall. A hollow screw 608 is provided on the mounting surface of the filter housing 603 located at the rear cabin for passing the cable and installing the combined filter 6. During installation, the mounting surface of the filter housing 603 is fitted with the filter mounting plate 102, and the hollow screw 608 passes through the filter mounting plate 102 and is fixed by its nut. The filter housing 603 and its front cover plate 606 and rear cover plate 607 are made of low-carbon steel sheet metal and nickel-plated on the surface, with excellent shielding and grounding comprehensive performance.

[0055] The output of combined filter 6 enters the cabin through a waveguide, providing a high degree of electromagnetic isolation between the input and output. Combined filter 6 also features an independent shielding structure to ensure high shielding efficiency for the entire wallbox. To ensure a smooth discharge circuit, low-impedance conductive connections must be established between the wallbox housing and the cabin wall, and between the combined filter and the wallbox housing. Combined filter 6's internal circuitry is low-pass filtering, with electromagnetic isolation between the input and output.

[0056] Existing transient protection devices are primarily developed and manufactured for lightning pulses. Their inherent nonlinear parameters can significantly change under nanosecond-level pulses, making the original parameters no longer applicable. This invention addresses the needs of HEMP electromagnetic pulse protection and the integrity of signal transmission, overcoming the limitations of single transient protection devices, such as large junction capacitance and high protection voltage. By combining multiple transient protection devices, the invention effectively protects downstream circuits.

[0057] According to the characteristics of commonly used transient protection devices, different transient protection devices are selected for different signal interfaces: for low-frequency signals such as level signals and telephone lines, varistors are selected in combination with EMI filter circuits to achieve LEMP and HEMP combined protection; for communication serial ports with differential signal transmission such as RS422, RS485, and CAN lines, gas discharge tubes are selected in combination with EMI filter circuits to achieve LEMP and HEMP combined protection; for high-frequency signals such as RJ45 network ports, gas discharge tubes are selected in combination with EMI filter circuits to achieve LEMP and HEMP combined protection. Electrostatic protection components are added at the end of the EMI filter circuit to further reduce residual voltage and ensure that the protection effect meets the requirements.

[0058] When selecting a transient protection device, the present invention first determines its starting voltage. The operating voltage of the signal interface is relatively low. Considering the response speed of the transient protection device, the varistor for low-frequency signals such as level signals and telephone lines uses a starting voltage of 150V; the gas discharge tube for the communication serial port, RJ45 network port, etc. uses a starting voltage of 150V. According to the pulse current injection (PCI) test requirements of GJB18848, the maximum line-to-ground peak current of the signal line is 2500A. The requirements for lightning protection are much greater than this. Therefore, the flow rate of the transient protection device can be selected according to the requirements of lightning protection, and is selected as 10kA. The electrostatic protection element at the end of the RJ45 network port EMI filter circuit is used to control the residual voltage. The flow rate requirement is extremely small, and the action voltage is selected as 15V.

[0059] The frequency range of HEMP electromagnetic pulses is distributed below 200MHz, and most of the energy (accounting for about 99%) is concentrated in the frequency band below 100MHz. The energy in the 1MHz~100MHz band has exceeded 89% of the total energy, while the energy below 10kHz only accounts for 0.1% of the total energy. Therefore, HEMP has the greatest impact on wireless communication equipment (such as shortwave and ultra-shortwave communication interfaces) in the 1MHz~100MHz band. Figure 2As shown, two levels of protection are implemented. Between antenna 11 and antenna tuner 12, there is an antenna tuner filter 9 (part of the antenna tuner system, not the signal wallbox) that discharges high-energy electromagnetic pulses (LEMP / HEMP) to the ground. Between antenna tuner 12 and shortwave radio 13 (at the cabin entrance window), there is a shortwave protection filter 8 that discharges the electromagnetic pulse energy a second time, ensuring that the radio (including sensitive units such as the internal power amplifier and low-noise amplifier) is not damaged. Shortwave protection filter 8 is designed for the RF signal transmission link, primarily suppressing transient interference from high-voltage and high-current HEMP signals coupled onto the RF transmission line. Shortwave protection filter 8 consists of a steady-state filter circuit and a lightning / HEMP protection circuit. The steady-state filter circuit is a bandpass filter, ensuring unattenuated transmission of passband signals while effectively attenuating high-frequency HEMP components above the passband frequency. The lightning / HEMP protection circuit bypasses and discharges high-voltage and high-current HEMP transient interference from the same frequency coupled onto the transmission line to the ground, protecting the radio's receiving port from damage. The principle of ultra-short wave protection filter is the same as that of short wave protection filter, but the passband and stopband are different.

[0060] See Figure 6 、 9 , for the shortwave protection filter 8 for shortwave signal protection, the installation in the wall box is as follows Figure 6 As shown, the shortwave protection filter 8 uses the same internal circuit as the combined filter 6. The shell structure of the shortwave protection filter 8 is the same as the filter shell 603 of the combined filter 6. The difference is that the filter shell of the shortwave protection filter does not include the partition 604, the through-hole capacitor 605 and the hollow screw 608. The filter shell of the shortwave protection filter adopts an integrated cavity shell, and its shell cavity is covered by an integrated cover plate. The shell of the shortwave protection filter includes two parts: a pre-stage protection circuit 601 and an EMI filter circuit 602. Radio frequency sockets are provided at both ends of the filter shell of the shortwave protection filter 8. The radio frequency sockets at both ends are coaxially arranged and serve as the input and output ends of the internal circuit of the shortwave protection filter respectively.

[0061] The RF input jack 81 of the shortwave protection filter is mounted on and exposed to the exterior panel 2, serving as a connector for the exterior panel 2. The RF output jack 82 of the shortwave protection filter 8 is mounted on and exposed to the interior panel 3, serving as a connector for the interior panel 3. Thus, the shortwave protection filter 8 forms an integrated structure with the exterior and interior panels 2 and 3, with the two RF jacks coaxial after installation. The internal circuitry of the shortwave protection filter 8 is bandpass filtering, and the input and output are non-isolated.

[0062] See Figure 3 、 5For microwave radio frequency interfaces whose operating frequencies are much higher than the main energy distribution frequency band of HEMP electromagnetic pulses, the frequency selection characteristics of the antenna determine that the coupling amount is extremely small (almost 0); the transmission cable uses a coaxial cable, and there is no field-line coupling, so lightning protection can be performed at the cabin entrance window. For the protection of microwave radio frequency interfaces, only two layers of protection isolation are required, namely the outer panel 2 and the inner panel 3. There is no need to set up a filter mounting plate 102 in the wall box. The radio frequency protection filter 7 directly uses a microwave radio frequency lightning arrester, and its input end is electrically connected to the connector socket 5 of the outer panel 2, and its output end is electrically connected to the connector socket 5 of the inner panel 3 through a microwave cable 18. The connector socket 5 corresponding to the microwave radio frequency interface is a microwave connector (through-the-wall) socket. Through two electromagnetic isolations, the high shielding efficiency of the entire device is guaranteed. A conductive pad is configured on the assembly surface of the connector socket 5 to further improve the shielding efficiency of the wall box. The input end of the microwave RF lightning arrester is a J-type plug, which is installed on the microwave connector (through-wall) socket of the outer panel 2. The output end is a K-type plug, which is connected to the microwave connector (through-wall) socket of the inner panel 3 through a microwave cable 18. It has low loop loss and high reliability.

[0063] When installing the signal wall box, the signal interfaces that require the wall box to have three-layer isolation function can be grouped into one signal wall box, and the signal interfaces that require the wall box to have two-layer isolation function (that is, the wall box does not have a filter installation plate 102) can be grouped into one signal wall box. The same signal wall box can also be partitioned according to the signal type, and the signal interfaces that require three-layer isolation and two-layer isolation can be partitioned to achieve partitioned installation and functional division.

[0064] Figure 10 、 11 The figure shows an external structure of a signal wall box. Figure 10 This is the axial structure seen from the side of the outer panel 2. Figure 11 This is the axial structure seen from the cabin panel 3. The wall box shape can be designed according to the specific installation location requirements of the shelter to meet the needs of convenient operation.

[0065] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness, characterized in that: Including shell, outer panel, inner panel and filter; The shell is closed at its periphery and open at both ends, and its periphery wall penetrates the cabin board of the square cabin; the outer panel and the inner panel are respectively installed at the outer and inner ends of the shell, and the two open ends are correspondingly closed; the outer panel and the inner panel are respectively provided with a plurality of connector sockets, and a corresponding group of connector sockets forms a signal interface; a plurality of filters are installed in the shell, and each signal interface corresponds to a corresponding filter, and the filters are connected in series in the signal circuit of a group of connector sockets; The filter includes a combined filter, a radio frequency protection filter and a shortwave protection filter; the combined filter is used for lightning protection, HEMP protection and EMI filtering of the low-pass signal interface, the radio frequency protection filter is used for lightning protection of the microwave radio frequency interface, and the shortwave protection filter is used for lightning protection, HEMP protection and EMI filtering of the shortwave signal interface.

2. The signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness according to claim 1 is characterized in that: The shell is provided with a mounting flange on the periphery outside the square cabin, and the mounting flange is provided with double rows of mounting holes that are staggered and evenly distributed, which are used to be fixedly connected to the outer wall of the square cabin panel by screws; the open ends of the shell are provided with mounting surfaces, which are used to respectively install the outer panel and the inner panel by screws; a low-impedance conductive shielding material is padded between the outer panel and the outer end mounting surface of the shell, and a low-impedance conductive shielding material is padded between the inner panel and the inner end mounting surface of the shell.

3. The signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness according to claim 2 is characterized in that: The combined filter includes a front-stage protection circuit and a rear-stage EMI filter circuit. The front-stage protection circuit is a combination of LEMP protection and HEMP protection. The EMI filter circuit is connected in series to the main signal transmission circuit. The input end of the front-stage protection circuit is connected to the main signal transmission circuit at the front end of the EMI filter circuit, and its output end is grounded. The front-stage protection circuit includes a transient protection device, which is a varistor or a gas discharge tube.

4. The signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness according to claim 3 is characterized in that: The combined filter through-wall lead-type filter comprises a filter housing, wherein the internal cavity of the filter housing is divided into a front compartment and a rear compartment by a partition, the front-stage protection circuit is installed in the front compartment and is located at the front end of the internal circuit of the combined filter, and the EMI filter circuit is installed in the front compartment and the rear compartment; a through-hole capacitor is installed on the partition for electromagnetic isolation of the input / output of the combined filter; the front compartment and the rear compartment are sealed by a front cover plate and a rear cover plate respectively; the outer end surface of the filter housing facing away from the cover plate is its mounting surface, and the mounting surface of the filter housing is covered with a conductive material for grounding; a hollow screw is provided on the mounting surface of the filter housing located at the rear compartment for passing the cable and installing the combined filter.

5. The signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness according to claim 4 is characterized in that: The filter housing and its front cover and rear cover are made of low-carbon steel sheet metal, with the surface nickel-plated, and have comprehensive shielding and grounding properties.

6. The signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness according to claim 4 is characterized in that: The shortwave protection filter adopts the same filter housing structure as the combined filter, and the internal circuit is the same as the internal circuit of the combined filter. The difference is that two radio frequency sockets are coaxially provided at both ends of the filter housing of the shortwave protection filter, serving as the input end and output end of the internal circuit of the shortwave protection filter respectively; the radio frequency socket at the input end of the shortwave protection filter is simultaneously installed in conjunction with the outer cabin panel and serves as the connector socket of the outer cabin panel; the radio frequency socket at the output end of the shortwave protection filter is simultaneously installed in conjunction with the inner cabin panel and serves as the connector socket of the inner cabin panel; the shortwave protection filter is used in conjunction with an external antenna tuner filter.

7. The signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness according to claim 2 is characterized in that: The radio frequency protection filter is a microwave radio frequency lightning arrester.

8. The signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness according to claim 2 is characterized in that: When the combined filter is installed in the wall box, a filter mounting plate is fixed inside the shell. The filter mounting plate is located between the outer panel and the inner panel, electromagnetically isolating the inner and outer ends of the wall box. The combined filter is installed on both sides of the filter mounting plate. At this time, the wall box forms three layers of isolation, including isolation of the filter mounting plate, isolation of the outer panel and isolation of the inner panel.

9. The signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness according to claim 2 is characterized in that: When the shortwave protection filter and the radio frequency protection filter are installed in the wall box, the wall box forms two layers of isolation, including isolation of the outer panel and isolation of the inner panel.

10. The signal wall box with strong electromagnetic pulse combined protection and high shielding effectiveness according to claim 2 is characterized in that: The low-pass signal interface includes a level signal, a telephone line, a communication serial port, and an RJ45 network port.

Images