Lightning protection module

Abstract

This invention proposes a surge protection module, comprising a common input port for receiving radio frequency (RF), control, and power signals. An RF channel is connected between the common input port and the RF output port. A control channel is connected in parallel to the RF channel via a first hollow inductor, with its output connected to the control output port. A power channel is connected in parallel to the RF channel via a second hollow inductor, with its output connected to the power output port. One pin of each of the first and second hollow inductors is connected to the RF channel pad, and the other pin is connected to the corresponding channel. This invention, through a one-to-three topology using the RF channel as the main line and employing hollow inductors to "bridge" and parallel the control and power channels, avoids the antenna effect at the physical connection points of traditional series filter circuits. This results in a RF channel voltage standing wave ratio (VSWR) as low as 1.1 and an insertion loss of less than 1 dB, while the control channel insertion loss is less than 0.5 dB, significantly improving signal transmission quality. Simultaneously, it simplifies the circuit structure, laying the foundation for achieving high isolation and mass production.

Description

Technical Field

[0001] This invention relates to the field of lightning protection technology, and in particular to a lightning protection module. Background Technology

[0002] One-line communication technology refers to the transmission of radio frequency signals, control signals, and power signals through a single port, followed by separation into three independent signals at the terminal. It is widely used in communication base stations, radar systems, antenna combiners, and other scenarios. To ensure effective separation and transmission quality between different signals, while also meeting lightning protection requirements, signal splitting and lightning protection functions are typically integrated into the one-line communication module.

[0003] Currently, most existing surge protection modules use a combination of low-pass and high-pass filter circuits to achieve signal separation, and combine this with multi-stage surge protection circuits for lightning suppression. For example, see the attached diagram. Figure 1 As shown, the RF circuit 20 uses the high-pass principle to pass the RF signal, while the DC circuit 60 and the data communication circuit 50 first pass through the low-pass filter 30 for signal separation, and then perform lightning protection respectively. The lightning protection circuit 40 adds a DC blocking capacitor and an inductor to further separate the DC circuit 60 and the data communication circuit 50, and finally realizes one-to-three output.

[0004] However, the above-mentioned existing technical solutions have the following shortcomings:

[0005] First, when the circuit topology is relatively simple, the isolation between the output ports is often insufficient, making it difficult to meet the system's requirement for high isolation between channels (e.g., above 50dB). If a cavity structure design is adopted to improve isolation, it will lead to a more complex product structure, increased size, and higher cost.

[0006] Second, existing solutions typically do not consider lightning residual voltage control in the RF channel. Lightning protection design is mainly focused on the low-pass port (i.e., the control and power channel), and often uses multi-level lightning protection circuits, which increases the number of components and circuit complexity.

[0007] Third, the complex cavity structure and the sensitivity of the circuit to component parameters lead to poor product consistency and assembly process consistency. The performance of different batches of products is prone to deviation, and manual fine-tuning of component parameters is often required during production, which is not conducive to mass production.

[0008] In summary, the technical solution uses a series multi-stage filter circuit with an independent cavity structure. The physical connection points of the signal path are prone to antenna effects, which degrades the RF transmission performance. At the same time, the complex cavity structure and multi-stage circuit are highly sensitive to the device parameters, which further exacerbates the problems of poor product consistency and high assembly difficulty. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention proposes a lightning protection module to solve the problem of existing one-line lightning protection schemes that employ series multi-stage filtering and cavity-splitting structures, which suffer from the difficulty of balancing antenna effect and manufacturability.

[0010] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0011] The surge protection module includes: a common input port for simultaneously receiving radio frequency (RF) signals, control signals, and power signals; an RF output port, a control output port, and a power output port; an RF channel connected between the common input port and the RF output port; a control channel connected in parallel to the RF channel via a first hollow inductor, with the output of the control channel connected to the control output port; and a power channel connected in parallel to the RF channel via a second hollow inductor, with the output of the power channel connected to the power output port. One pin of each of the two hollow inductors is directly connected to a pad on the RF channel, and the other pin is connected to the corresponding control channel or power channel. This invention, using a 1-to-3 topology with the RF channel as the main line and hollow inductors "bridging" the control and power channels in parallel, avoids the antenna effect at the physical connection points of traditional series filter circuits. This results in a RF channel voltage standing wave ratio as low as 1.1 and an insertion loss of less than 1 dB, while the control channel insertion loss is less than 0.5 dB, significantly improving signal transmission quality. Simultaneously, it simplifies the circuit structure, laying the foundation for achieving high isolation and mass production.

[0012] Furthermore, in order to discharge the lightning energy of the radio frequency channel and control the residual voltage, a second ceramic capacitor is connected in series in the radio frequency channel, and a third hollow inductor is connected in parallel to ground.

[0013] Furthermore, in order to discharge the lightning energy of the control channel and improve the isolation, a DC blocking capacitor and a fourth hollow inductor are connected in series in the control channel, and an ESD device and a second ceramic capacitor are connected in parallel to ground.

[0014] Furthermore, in order to discharge the lightning energy of the power channel and match the residual voltage to different power supply voltages, a magnetic core inductor is connected in series in the power channel, and a bidirectional lightning protection TVS tube, a unidirectional lightning protection TVS tube, a first ceramic capacitor, and a second ceramic capacitor are connected in parallel to ground.

[0015] Furthermore, in order to improve the shielding performance of the control channel and prevent signal leakage, a shielding shell is also included, which is set in the circuit board area corresponding to the control channel. Glass beads are provided on the shielding shell to realize the signal connection between the inside and outside of the shielding shell.

[0016] Furthermore, in order to integrate the various components and form a complete module, a housing and a cover plate are also included. The housing has a groove in which the circuit board components are installed, and the cover plate is placed on the housing.

[0017] Furthermore, to enhance the port connector's fixing strength and help improve shielding performance, the interface RF connector is mounted on the housing, and the tail pins are soldered to the printed circuit board.

[0018] Furthermore, to avoid antenna effects and ensure RF signal quality, the width of the pad connecting the first or second hollow inductor to the RF channel is equal to the width of the RF channel's transmission line.

[0019] Furthermore, in order to reduce product costs and improve manufacturability, the board material of the circuit board component is FR4 high TG board material.

[0020] Furthermore, in order to achieve a standard radio frequency interface, the common input port, radio frequency output port, control output port, and power output port are all SMA connector interfaces.

[0021] The beneficial effects of this invention are:

[0022] 1. Based on the frequency characteristics of lightning waveforms and the frequency differences of radio frequency signals (1.6±0.1GHz), control signals (2MHz), and power signals (48VDC), this invention adopts a bandpass parallel topology to achieve single-port input and three-port split output, which simplifies the circuit while taking into account signal transmission and lightning protection performance.

[0023] 2. This invention adopts a one-to-three topology with the radio frequency channel as the main line and the control channel and power channel directly "bridged" through the hollow inductor pins. This avoids the antenna effect at the physical connection point of the traditional series filter circuit, so that the voltage standing wave ratio of the radio frequency channel can be as low as 1.1 or less, the insertion loss is less than 1dB, and the insertion loss of the control channel is less than 0.5dB, which significantly improves the signal transmission quality.

[0024] 3. This invention employs differentiated lightning protection and residual voltage control schemes for the radio frequency (RF) channel, control channel, and power supply channel: the RF channel discharges lightning energy through DC blocking capacitors and air-core inductors to ground; the control channel discharges lightning energy through DC blocking capacitors, air-core inductors, and ESD devices; and the power supply channel discharges lightning energy through magnetic core inductors and TVS diodes. This results in lightning residual voltages of less than 10V for the RF and control channels and less than 100V for the power supply channel, and the ability to match different power supply voltages, thus achieving effective suppression of indirect lightning.

[0025] 4. This invention integrates all channels using a single piece of FR4 high-TG board material, adding a shielding shell only to the control channel. Without the need for a complex cavity structure, the isolation between the three output ports is greater than 50dB, which is far higher than the requirements of general systems. At the same time, it greatly simplifies the product structure and reduces weight and cost.

[0026] 5. The power channel of the present invention can be replaced with TVS tubes of different specifications, which can be adapted to various power supply operating voltages and flexibly adjust the residual voltage of lightning.

[0027] 6. This invention optimizes the selection of standard components through simulation, and extensively uses standard parts such as ceramic capacitors and air inductors of the same specifications, which reduces the types of components, improves product consistency and assembly process consistency, avoids manual fine-tuning of component parameters, and is conducive to mass production.

[0028] 7. This invention lowers the flange mounting surface of the SMA connector by 0.5mm, enhancing the fixing strength of the port connector, helping to improve the shielding performance of the product, and further ensuring the realization of high isolation.

[0029] 8. The present invention adopts the above technical solution and can achieve the following performance indicators: RF channel insertion loss ≤1dB, voltage standing wave ratio ≤1.3, and voltage standing wave ratio ≤1.1 under optimal operating conditions; control channel insertion loss ≤0.5dB; lightning residual voltage of both RF channel and control channel is less than 10V, and lightning residual voltage of power supply channel is less than 100V; isolation between the three output ports ≥50dB. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the signal branching topology of a current lightning protection module.

[0032] Figure 2 This is a schematic diagram of the signal branching topology of the present invention.

[0033] Figure 3 This is the circuit schematic diagram of the present invention.

[0034] Figure 4 This is a schematic diagram of the structure of the present invention.

[0035] Figure 5 This is a partial schematic diagram of the glass bead adapter of the present invention.

[0036] Figure 6 This is a schematic diagram of the hollow inductor "bridge" of the present invention.

[0037] In the diagram: 20. RF circuit; 30. Low-pass filter; 40. Surge protection circuit; 50. Data communication circuit; 60. DC circuit; 1. Common input port; 1-1. RF signal output port; 1-2. Control signal output port; 1-3. Power signal output port; 2. Shielding shell; 3. Glass bead; 4. Circuit board component; 41. Magnetic core inductor; 42. Printed circuit board; 43. Surge protection bidirectional TVS diode; 44. Surge protection unidirectional TVS diode; 45. Air-core inductor; 451. First air-core inductor; 452. Second air-core inductor; 453. Third air-core inductor; 454. Fourth air-core inductor; 46. DC blocking capacitor; 47. First ceramic capacitor; 48. ESD device; 49. Second ceramic capacitor; 5. Housing; 6. Interface RF connector; 7. Cover plate; 8. RF channel; 9. Control channel; 10. Power channel. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The surge protection module described in Embodiment 1 of this invention is preferably a one-wire surge protection module, see [link / reference]. Figure 2 and Figure 3 The surge protection module includes a common input port 1, an RF output port 1-1, a control output port 1-2, and a power output port 1-3. RF channel 8 is connected between the common input port 1 and the RF output port 1-1. Figure 6 As shown, control channel 9 is connected in parallel to RF channel 8 via the first hollow inductor 451. Figure 2 As shown, the output of control channel 9 is connected to control output port 1-2. Power channel 10 is connected in parallel to RF channel 8 through the second hollow inductor 452. Figure 2 As shown, the output of power channel 10 is connected to power output ports 1-3. RF channel 8 forms an RF high-pass circuit, control channel 9 forms a control low-pass circuit, and power channel 10 forms a power pass-through circuit.

[0040] In this embodiment, as Figure 3As shown, 45 represents hollow inductors of the same specification, including L1, L2, L3, and L4 in the circuit; specifically, the first hollow inductor 451 is hollow inductor L2, the second hollow inductor 452 is hollow inductor L4, the third hollow inductor 453 is hollow inductor L1, and the fourth hollow inductor 454 is hollow inductor L3. 49 represents ceramic capacitors of the same specification, including C1, C2, C4, C5, and C6 in the circuit; 47 is an independently specified ceramic capacitor C7. The specific connection positions and functions of each component in the circuit will be explained in conjunction with the circuit schematic. Furthermore, both the first hollow inductor 451 and the second hollow inductor 452 are bridged using hollow inductors.

[0041] Furthermore, specifically, one pin of each of the first hollow inductor 451 (hollow inductor L2) and the second hollow inductor 452 (hollow inductor L4) is directly connected to the pad on the RF channel 8, and the other pin is connected to the corresponding control channel 9 or power channel 10 respectively.

[0042] like Figure 6 As shown, taking the first hollow inductor 451, i.e., hollow inductor L2, as an example, one pin of the hollow inductor is directly soldered to the transmission line of the RF channel 8, and the width of the solder pad is equal to the width of the transmission line of the RF channel 8. The other pin is connected to the line of the control channel 9, thereby avoiding the antenna effect and ensuring the quality of the RF signal.

[0043] Example 2 further defines the surge protection circuit for the radio frequency channel 8 based on Example 1. See also... Figure 3 A second ceramic capacitor 49 is connected in series in the RF channel 8, and a third air-core inductor 453 is connected in parallel to ground. The second ceramic capacitor 49 includes capacitors C1 and C2, connected in series in the RF channel to isolate DC signals, allowing only RF signals to pass through. The air-core inductor 453 is inductor L1, with one end connected between capacitors C1 and C2 and the other end grounded. It presents high impedance to RF signals and low impedance to low-frequency lightning signals, used to discharge lightning energy from the RF channel and control residual voltage.

[0044] Example 3 further defines the surge protection circuit of control channel 9 based on Example 1 or 2. A DC blocking capacitor 46 and a fourth hollow inductor 454 are connected in series in control channel 9, and an ESD device 48 and two second ceramic capacitors 49 are connected in parallel to ground. Here, the DC blocking capacitor 46 is capacitor C3, and the fourth hollow inductor 454 is inductor L3; both are connected in series in the control channel to isolate DC signals and allow control signals to pass through. The ESD device 48 consists of electrostatic discharge tubes D1 and D2, connected in parallel to different nodes of the control channel. Capacitors C4 and C5 of the second ceramic capacitors 49 are also connected in parallel to different nodes of the control channel. These components together achieve surge energy discharge from the control channel and improve the isolation between channels.

[0045] Example 4 further defines the surge protection circuit of the power supply channel 10 based on Example 1 or 2. A magnetic core inductor 41 is connected in series in the power supply channel 10, and a bidirectional surge protection TVS diode 43, a unidirectional surge protection TVS diode 44, a first ceramic capacitor 47, and a second ceramic capacitor 49 are connected in parallel to ground. Figure 3 As shown, the magnetic core inductor 41 is inductor L5, which presents high impedance to both radio frequency signals and control signals. The bidirectional surge protector TVS diodes 43 are D3 and D4, and the unidirectional surge protector TVS diodes 44 are D5 and D6, used to discharge lightning energy and control residual voltage. The first ceramic capacitor 47 is capacitor C7, and the second ceramic capacitor 49 is capacitor C6; both are connected in parallel between the power supply path and ground to improve isolation. By selecting TVS diodes of different specifications, different power supply operating voltages can be matched and residual voltage controlled.

[0046] In a preferred embodiment, the bidirectional surge protector TVS diode 43 and the unidirectional surge protector TVS diode 44 in the power channel 10 are replaceable devices. By replacing TVS diodes of different specifications, different power supply voltages can be adapted and the output residual voltage can be adjusted.

[0047] Example 5: This example adds a shielding structure to Example 1. For example... Figure 4 and Figure 5 As shown, the module also includes a shielding shell 2, which is located on the circuit board area corresponding to the control channel 9. A glass bead 3 is mounted on the shielding shell 2 to enable signal connection between the inside and outside of the shielding shell. The pins at both ends of the glass bead 3 are soldered to the copper-clad wires on the printed circuit board 42, thereby enabling the entry and exit of control signals and preventing signal leakage when passing through the shielding shell.

[0048] Example 6: This example adds a shell assembly structure to Example 5. For example... Figure 4 As shown, the module also includes a housing 5 and a cover plate 7. The housing 5 has a recessed groove in which the circuit board component 4 is installed, and the cover plate 7 fits over the housing 5. The interface RF connector 6 is mounted on the housing 5, with its flange mounting surface recessed by 0.5mm and its tail pins soldered to the printed circuit board 42, thereby enhancing the connector's fixing strength and improving shielding performance. The circuit board component 4 uses FR4 high-TG standard board material, reducing costs. All circuit components in this module are integrated onto a single piece of FR4 high-TG board material, abandoning the traditional complex compartmentalized structure and only using a shielding shell in the control channel, significantly simplifying the product structure. The common input port 1, RF output port 1-1, control output port 1-2, and power output port 1-3 all use SMA connector interfaces.

[0049] Example 7 illustrates the complete operation of this surge protection module. See also... Figures 1 to 4The radio frequency (RF) signal, control signal, and power signal are simultaneously input from the common input port 1. The RF signal is transmitted along the RF channel 8, and after DC isolation by two second ceramic capacitors 49 (i.e., C1, C2), it is output from the RF output port 1-1. At the same time, the third hollow inductor 453 (L1) discharges the low-frequency lightning component on the RF channel to ground. The control signal is led out in parallel from the RF channel 8 through the first hollow inductor 451 (L2), and after passing through the DC blocking capacitor 46 (C3) and the fourth hollow inductor 454 (L3) in sequence, it is output from the control output port 1-2. The parallel ESD devices 48 (D1, D2) and the two second ceramic capacitors 49 (i.e., C4, C5) discharge lightning energy and improve isolation. The power signal is led out in parallel from the RF channel 8 through the second hollow inductor 452 (L4), and then output from the power output port 1-3 after passing through the magnetic core inductor 41 (L5). The parallel-connected bidirectional surge protector TVS diodes 43 (D3, D4), unidirectional surge protector TVS diodes 44 (D5, D6), first ceramic capacitor 47 (C7), and a second ceramic capacitor 49 (C6) mainly discharge lightning energy and control residual voltage. The shielding shell 2 partially shields the control channel to ensure that the isolation between channels is greater than 50dB.

[0050] The above description is merely 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 foregoing embodiments, those skilled in the art should understand that any modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some or all of the technical features thereof, within the spirit and principles of the present invention, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A lightning protection module, characterized in that, include: A common input port (1) is used to simultaneously receive radio frequency signals, control signals, and power signals; a radio frequency output port (1-1), a control output port (1-2), and a power output port (1-3); a radio frequency channel (8) is connected between the common input port (1) and the radio frequency output port (1-1); a control channel (9) is connected in parallel to the radio frequency channel (8) through a first hollow inductor (451), and the output of the control channel (9) is connected to the control output port (1-2); a power channel (10) is connected in parallel to the radio frequency channel (8) through a second hollow inductor (452), and the output of the power channel (10) is connected to the power output port (1-3); one pin of each of the first hollow inductor (451) and the second hollow inductor (452) is directly connected to the pad on the radio frequency channel (8), and the other pin is connected to the corresponding control channel (9) or power channel respectively.

2. The lightning protection module according to claim 1, characterized in that, The radio frequency channel (8) is connected in series with a second ceramic capacitor (49) and in parallel with a third hollow inductor (453) to ground to discharge the lightning energy of the radio frequency channel.

3. The lightning protection module according to claim 1 or 2, characterized in that, The control channel (9) is connected in series with a DC blocking capacitor (46) and a fourth hollow inductor (454), and is connected in parallel with an ESD device (48) and a second ceramic capacitor (49) to ground.

4. The lightning protection module according to claim 1 or 2, characterized in that, The power supply channel is connected in series with a magnetic core inductor (41), and in parallel with a bidirectional surge protector TVS tube (43) and a unidirectional surge protector TVS tube (44), as well as a first ceramic capacitor (47) and a second ceramic capacitor (49).

5. The lightning protection module according to claim 1 or 2, characterized in that, It also includes a shielding shell (2), which is set in the circuit board area corresponding to the control channel (9). Glass beads (3) are inserted through the shielding shell (2) to realize the signal connection between the inside and outside of the shielding shell.

6. The lightning protection module according to claim 5, characterized in that, It also includes a housing (5) and a cover plate (7), wherein the housing (5) has a groove, the circuit board component (4) is installed in the groove, and the cover plate (7) covers the housing (5).

7. The lightning protection module according to claim 6, characterized in that, The interface RF connector (6) is mounted on the housing (5), and the tail pins are soldered to the printed circuit board (42).

8. The lightning protection module according to claim 1, 2, 6, or 7, characterized in that, The width of the pad connecting the first hollow inductor (451) or the second hollow inductor (452) to the radio frequency channel (8) is equal to the width of the transmission line of the radio frequency channel (8).

9. The lightning protection module according to claim 1, 2, 6, or 7, characterized in that, The circuit board component (4) is made of FR4 high TG board material.

10. The lightning protection module according to claim 1, 2, 6, or 7, characterized in that, The common input port (1), the radio frequency output port (1-1), the control output port (1-2), and the power output port (1-3) are all SMA connector interfaces.

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