Radio frequency protection device, system and equipment

Abstract

The utility model discloses a radio frequency protection device, a radio frequency protection system and radio frequency protection equipment. The radio frequency protection device comprises a first filtering module and a second filtering module, the first filtering module is respectively connected with the radio frequency link and the second filtering module, and the second filtering module is connected with the signal ground; the first filtering module is used for transmitting a first radio frequency signal of which the frequency is not in a first frequency band in an input signal to the second filtering module when the input signal is received, the input signal is input into a radio frequency link through the antenna interface, and the first filtering module is coupled with the radio frequency link; and the second filtering module is used for transmitting a second radio frequency signal of which the frequency is not in the second frequency band in the first radio frequency signal to the signal ground. According to the utility model, dual-band equivalent open circuit can be realized through the first filtering module and the second filtering module, and the grounding loop formed by the first filtering module and the second filtering module releases the signals except the first band and the second band in the input signals through the signal ground, thereby realizing dual-band radio frequency link protection.

Description

Technical Field

[0001] The utility model relates to the technical field of wireless communication, and in particular to a radio frequency protection device, system and equipment. Background Art

[0002] With the continuous development of the RF field, the reliability design of RF modules is becoming more and more important. Among them, the use environment of RF communication modules with external antenna connectors is complex and easily interfered by surge signals and electrostatic signals. In order to avoid high-level surge and electrostatic signals from damaging the RF link, corresponding protective devices are often set at the external antenna connector to protect the subsequent RF link.

[0003] However, the existing protection devices usually only consider the protection of single-band RF links. When protecting dual-band RF links, another protection device needs to be added to protect the other band, which increases the size of the RF module. This method is not only costly but also has a narrow scope of application. Therefore, how to provide an integrated protection device for dual-band RF links has become an urgent problem to be solved.

[0004] The above contents are only used to assist in understanding the technical solution of the present utility model and do not constitute an admission that the above contents are prior art. Utility Model Content

[0005] The main purpose of the utility model is to provide a radio frequency protection device, system and equipment, aiming to solve the technical problem of how to provide an integrated protection device for dual-band radio frequency links.

[0006] To achieve the above object, the utility model provides a radio frequency protection device, the radio frequency protection device comprising: a first filter module and a second filter module;

[0007] The first filter module is connected to the radio frequency link and the second filter module respectively, and the second filter module is connected to the signal ground;

[0008] The first filtering module is used for transmitting the first radio frequency signal in the input signal which is not within the first frequency band to the second filtering module when receiving the input signal, the input signal is input into the radio frequency link through the antenna interface, and the first filtering module is coupled to the radio frequency link;

[0009] The second filtering module is used to transmit the second radio frequency signal whose frequency is not within the second frequency band in the first radio frequency signal to the signal ground.

[0010] Optionally, the first filtering module includes: a band-stop filtering structure, and the second filtering module includes: a microstrip line;

[0011] The band-stop filter structure is connected to the microstrip line, and the microstrip line is connected to the signal ground;

[0012] The band-stop filter structure is used to transmit the first radio frequency signal in the input signal which is not within the first frequency band to the microstrip line when receiving the input signal;

[0013] The microstrip line is used to transmit the second radio frequency signal whose frequency is not within the second frequency band in the first radio frequency signal to the signal ground.

[0014] Optionally, the band-stop filter structure comprises: a flat capacitor unit, the flat capacitor unit comprises a first capacitor and a second capacitor, the first capacitor and the second capacitor are respectively arranged in adjacent PCB layers;

[0015] The flat capacitor unit is arranged between the microstrip line and the radio frequency link.

[0016] Optionally, the first filtering module includes: a microstrip line; the second filtering module includes: a filtering capacitor;

[0017] The microstrip line is provided with a slot and a pad, and the filter capacitor is fixed above the slot through the pad;

[0018] One end of the microstrip line is connected to the radio frequency link, and the other end is connected to the signal ground.

[0019] Optionally, the second filtering module further includes: a band-stop filtering structure;

[0020] One end of the band-stop filter structure is connected to the microstrip line, and the other end is connected to the signal ground.

[0021] Optionally, the band-stop filter structure comprises: a co-digital structure, wherein the co-digital structure is a serpentine-arranged slot;

[0022] The interdigital structure is arranged between the microstrip line and the signal ground.

[0023] In addition, to achieve the above-mentioned purpose, the utility model also proposes a radio frequency protection system, the radio frequency protection system comprising: an antenna interface, a radio frequency communication module and the radio frequency protection device as described above;

[0024] The antenna interface is connected to the radio frequency communication module via the radio frequency link;

[0025] One end of the radio frequency protection device is connected to the radio frequency link, and the other end is connected to the signal ground.

[0026] Optionally, the radio frequency protection system further includes: a combiner;

[0027] The combiner is arranged between the radio frequency protection device and the radio frequency communication module.

[0028] In the utility model, a radio frequency protection device, system and equipment are disclosed, and the radio frequency protection device includes: a first filter module and a second filter module; the first filter module is connected to the radio frequency link and the second filter module respectively, and the second filter module is connected to the signal ground; the first filter module is used to transmit the first radio frequency signal whose frequency is not within the first frequency band in the input signal to the second filter module when receiving the input signal, the input signal is input into the radio frequency link through the antenna interface, and the first filter module is coupled with the radio frequency link; the second filter module is used to transmit the second radio frequency signal whose frequency is not within the second frequency band in the first radio frequency signal to the signal ground. In the utility model, the grounding loop composed of the first filter module and the second filter module can release all signals except the first frequency band and the second frequency band in the input signal through the signal ground, thereby realizing the protection of the subsequent radio frequency link; at the same time, the utility model can realize the dual-band equivalent open circuit of the first frequency band radio frequency signal and the second frequency band radio frequency signal based on the first filter module and the second filter module, ensuring that the target dual-band radio frequency signal will not be greatly lost due to the introduction of the protection device, thereby realizing the dual-band radio frequency protection while avoiding the introduction of large radio frequency link loss. Therefore, compared with the existing protective device composed of two single-band protectors, the utility model can realize the equivalent open circuit of the dual-band through the first filter module and the second filter module, and can greatly reduce the size of the protector while protecting the dual-band RF link, and broaden the use scenario. At the same time, the first filter module in the utility model includes: a band-stop filter structure, and the second filter module includes: a microstrip line; the band-stop filter structure is connected to the microstrip line, and the microstrip line is connected to the signal ground; the band-stop filter structure is used to transmit the first RF signal in the input signal whose frequency is not within the first frequency band to the microstrip line when receiving the input signal; the microstrip line is used to transmit the second RF signal in the first RF signal whose frequency is not within the second frequency band to the signal ground. In addition, the band-stop filter structure includes: a flat capacitor unit, the flat capacitor unit includes a first capacitor and a second capacitor, and the first capacitor and the second capacitor are respectively arranged in adjacent PCB layers; the flat capacitor unit is arranged between the microstrip line and the RF link. Compared with the existing technical means that require the additional use of grounding inductors or TVS tubes, the utility model does not require any components and only requires the use of a special PCB copper sheet configuration. Therefore, the utility model can construct a low-cost RF protection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the first module of the radio frequency protection device of the utility model;

[0030] Figure 2 This is a schematic diagram of the second module of the radio frequency protection device of the utility model;

[0031] Figure 3 This is a schematic diagram of the flat plate capacitor and microstrip line structure of the radio frequency protection device of the utility model;

[0032] Figure 4 This is a schematic diagram of the third module of the radio frequency protection device of the utility model;

[0033] Figure 5 It is a top view of the structure of the microstrip line in the radio frequency protection device of the utility model;

[0034] Figure 6 This is a schematic diagram of the fourth module of the radio frequency protection device of the utility model;

[0035] Figure 7 This is a schematic diagram of the fifth module of the radio frequency protection device of the utility model;

[0036] Figure 8 It is a top view of the structure of the co-digital structure in the radio frequency protection device of the utility model;

[0037] Fig. 9 It is a schematic diagram of the microstrip line and the co-digital structure of the radio frequency protection device of the utility model;

[0038] Fig.10 It is a schematic diagram of the simulation waveform of the radio frequency protection device of the utility model;

[0039] Fig.11 This is the first structural block diagram of the radio frequency protection system of the utility model;

[0040] Fig.12 This is the second structural block diagram of the radio frequency protection system of the present utility model.

[0041] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0042] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0043] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0044] It should be noted that the descriptions of "first", "second", etc. in the embodiments of the present utility model are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0045] It should be understood that the existing RF protection means can be achieved by designing an inductor at the antenna interface 1 and grounding it to discharge the interference signal (surge signal or electrostatic signal) input from the antenna port to the ground, thereby forming a protector to protect the subsequent RF link; in addition, the existing technology can also design a short-circuit microstrip line structure at the antenna interface, which is equivalent to an open circuit for the required frequency band RF signal, thereby reducing the impact on the RF link while discharging static electricity and surge signals. However, the first method is limited by the current-carrying performance of the capacitor itself, and the protection level for surges or static electricity is not high enough. Therefore, in some application scenarios (such as industrial-grade models), technical means with better protection performance are required; the second method can only be equivalent to an open circuit for a single RF band. For dual-band RF links, two microstrip line structures of different lengths need to be designed, which greatly increases the size of the protector and limits the application scenarios.

[0046] To solve the above problems, this embodiment can design a special structure to make it equivalent to a filter, so that based on the equivalent filter, a radio frequency protector that protects the dual-band radio frequency link is formed under the premise of ensuring radio frequency performance. Figure 1 , Figure 1 This is a schematic diagram of the first module of the radio frequency protection device of the present invention.

[0047] like Figure 1 As shown, the radio frequency protection device described in this embodiment includes: a first filtering module 10 and a second filtering module 20;

[0048] The first filter module 10 is connected to the radio frequency link 1 and the second filter module 20 respectively, and the second filter module 20 is connected to the signal ground 2;

[0049] The first filtering module 10 is used for transmitting the first radio frequency signal in the input signal which is not within the first frequency band to the second filtering module 20 when receiving the input signal, the input signal is input into the radio frequency link 1 through the antenna interface, and the first filtering module 10 is coupled to the radio frequency link 1;

[0050] The second filtering module 20 is used to transmit the second RF signal whose frequency is not within the second frequency band in the first RF signal to the signal ground 2.

[0051] It can be understood that the input signal transmitted by the above-mentioned radio frequency link 1 may include external radio frequency signals, electrostatic signals and surge signals. The above-mentioned first filter module 10 may be connected to the radio frequency link 1 and the second filter module 20 at the same time, and connected to the signal ground 2 through the second filter module 20, so as to release the electrostatic signals and surge signals in the input signal except the first frequency band radio frequency signals and the second frequency band radio frequency signals through the signal ground 2.

[0052] In a specific implementation, the RF link 1 can be a signal transmission link between an antenna interface and a RF communication module (or combiner). When the RF link 1 transmits an input signal input by the antenna interface to the RF communication module, the input signal will also flow through the first filter module 10. In this embodiment, it is hoped that the signal input to the RF communication module 3 in the above-mentioned input signal can be a RF signal corresponding to the above-mentioned first frequency band and the above-mentioned second frequency band. Therefore, when receiving the input signal, the first filter module 10 can first transmit the first RF signal whose frequency is not within the first frequency band in the input signal to the second filter module 20, and the second filter module 20 then transmits the second RF signal whose frequency is not within the second frequency band in the first RF signal to the signal ground 2, thereby grounding and releasing all signals except the first frequency band and the second frequency band, and retaining the normal transmission of the RF signals corresponding to the first frequency band and the second frequency band on the RF link. It is easy to understand that if RF signal protection of three frequency bands is required, this embodiment can add a corresponding filter module for further protection.

[0053] To sum up, in this embodiment, the grounding loop composed of the first filter module 10 and the second filter module 20 releases all signals in the input signal except the first frequency band and the second frequency band through the signal ground 2, thereby realizing the grounding of surge signals and electrostatic signals, and further realizing the protection of the subsequent RF link; at the same time, the first filter module 10 can realize the equivalent open circuit of the RF signal of the first frequency band, and the second filter module 20 can realize the equivalent open circuit of the RF signal of the second frequency band. Therefore, this embodiment can realize the dual-band equivalent open circuit of the RF signal of the first frequency band and the RF signal of the second frequency band based on the first filter module 10 and the second filter module 20, ensuring that the target dual-band RF signal will not suffer a large loss due to the introduction of the protection device, thereby achieving dual-band RF protection while avoiding the introduction of large RF link losses. Therefore, compared with the prior art, this embodiment can achieve an equivalent open circuit in dual bands, thereby protecting the dual-band radio frequency link; for the dual-band antenna port, compared with the existing protection device composed of two single-band protectors, this embodiment can greatly reduce the size of the protector, improve the protection capability, and broaden the usage scenarios.

[0054] Further, as an implementable embodiment, refer to Figure 2 , Figure 2 Schematic diagram of the second module of the radio frequency protection device of the utility model. In this embodiment, the first filtering module 10 includes: a band-stop filtering structure 101, and the second filtering module 20 includes: a microstrip line 201;

[0055] The band-stop filter structure 101 is connected to the microstrip line 201, and the microstrip line 201 is connected to the signal ground 2;

[0056] The band-stop filter structure 101 is used to transmit the first radio frequency signal whose frequency is not within the first frequency band in the input signal to the microstrip line 201 when receiving the input signal;

[0057] The microstrip line 201 is used to transmit the second radio frequency signal whose frequency is not within the second frequency band in the first radio frequency signal to the signal ground 2.

[0058] It should be noted that, in this embodiment, the first filter module 10 can be a band-stop filter structure 101, and the band-stop filter structure 101 can be an equivalent LC parallel structure, which can present a high impedance state to the first frequency band radio frequency signal. Therefore, the first frequency band radio frequency signal transmitted on the radio frequency link will not flow to the first filter module 10, but directly flow to the radio frequency communication module; the second filter module 20 can be a microstrip line 201. For a radio frequency signal in a certain frequency band, if the length of the microstrip line 201 is designed to be 1 / 4 times the wavelength corresponding to the frequency of the frequency band, then the microstrip line 201 is equivalent to an open circuit for the radio frequency signal in the frequency band, that is, the radio frequency signal will not pass through the microstrip line 201, but will be transmitted along the existing radio frequency link. Therefore, in this embodiment, when the second filter module 20 is a microstrip line 201 with a length equal to 1 / 4 times the wavelength corresponding to the second frequency band radio frequency signal, the microstrip line 201 can be equivalent to an open circuit for the second frequency band radio frequency signal in the first radio frequency signal transmitted by the band-stop filter structure 101. At this time, the second frequency band RF signal will also flow to the RF communication module along the original RF link 1, thereby transmitting the second RF signal whose frequency is not within the second frequency band in the first RF signal to the signal ground 2. It is easy to understand that the width of the microstrip line 201 can be designed according to specific needs. The larger the width, the smaller the resistance of the microstrip line 201 and the stronger the current carrying capacity.

[0059] It is easy to understand that, in order to save the volume of the RF circuit, the first filter module 10 and the second filter module 20 proposed in this embodiment can be directly constructed on the PCB board. Further, as an implementable embodiment, in this embodiment, the band-stop filter structure 101 includes: a flat capacitor unit, the flat capacitor unit includes a first capacitor and a second capacitor, and the first capacitor and the second capacitor are respectively arranged in adjacent PCB layers;

[0060] The flat capacitor unit is arranged between the microstrip line 201 and the radio frequency link 1 .

[0061] It should be understood that in this embodiment, a flat plate capacitor configuration can be used, that is, the above-mentioned flat plate capacitor unit is used as the above-mentioned band-stop filter structure 101. In practical applications, for ease of understanding, Figure 3 This is used as an example to illustrate the present invention, but does not further limit the implementation methods of this embodiment. Figure 3 The schematic diagram of the structure of the flat capacitor and microstrip line of the radio frequency protection device of the utility model is as follows: Figure 3 As shown, if it is assumed that the PCB board has six layers L1 to L6, in this embodiment, the microstrip line 201 can be set on the L6 layer, and its length is designed to be equivalent to the length of the open circuit of the second frequency band radio frequency signal, and the first capacitor and the second capacitor in the flat capacitor unit can be respectively located in adjacent PCB layers, such as Figure 3 The L2 and L3 layers in the filter. At this time, the first capacitor and the second capacitor can be equivalent to the capacitor C in the band-stop filter, and the parasitic inductance caused by the via structure between the L2 layer and the L3 layer can be equivalent to the inductor L in the band-stop filter. The two are connected in parallel to form LC parallel connection. Therefore, the above-mentioned flat capacitor unit can be equivalent to a band-stop filter. This embodiment can achieve an equivalent open circuit of the first frequency band RF signal by designing the size of the flat capacitor unit, and then can be combined with the microstrip line 201 to achieve a dual-band equivalent open circuit of the first frequency band RF signal and the second frequency band RF signal. Compared with the existing technical means that require the additional use of grounding inductors or TVS tubes, this embodiment does not require any components, and only requires the use of a special PCB copper foil configuration. Therefore, the RF protection device proposed in this embodiment has a lower cost.

[0062] It is easy to understand that the positions of the above-mentioned microstrip line 201 and the flat capacitor unit in the PCB board are not limited to the above-mentioned L6 layer and L2~L3 layers. In addition, in this embodiment, the above-mentioned first frequency band and the second frequency band can be 2.4G and 5G respectively, and can also be specifically set according to actual conditions. This embodiment does not impose any restrictions on this.

[0063] To summarize, this embodiment provides an integrated RF protector that can be used for dual-band antenna ports based on transmission line theory and filter-related theories. That is, this embodiment can achieve dual-band protection for RF signals in the first frequency band and RF signals in the second frequency band, and can meet the needs of high-level surge and electrostatic protection at a low cost.

[0064] The present embodiment discloses a radio frequency protection device, which includes: a first filter module and a second filter module; the first filter module is connected to the radio frequency link and the second filter module respectively, and the second filter module is connected to the signal ground; the first filter module, when receiving the input signal, transmits the first radio frequency signal whose frequency is not within the first frequency band in the received input signal to the second filter module receiving the input signal, the received input signal is input into the radio frequency link through the antenna interface, and the first filter module receiving the input signal is coupled with the radio frequency link receiving the input signal; the second filter module is used to transmit the second radio frequency signal whose frequency is not within the second frequency band in the first radio frequency signal to the signal ground. In the present embodiment, the grounding loop composed of the first filter module and the second filter module can release all signals except the first frequency band and the second frequency band in the input signal through the signal ground, thereby realizing the protection of the subsequent radio frequency link; at the same time, the present embodiment can realize the dual-band equivalent open circuit of the first frequency band radio frequency signal and the second frequency band radio frequency signal based on the first filter module and the second filter module, ensuring that the target dual-band radio frequency signal will not be greatly lost due to the introduction of the protection device, thereby realizing the dual-band radio frequency protection while avoiding the introduction of large radio frequency link loss. Therefore, compared with the existing protection device composed of two single-band protectors, this embodiment can realize the equivalent open circuit of the dual-band through the first filter module and the second filter module, and can greatly reduce the size of the protector while protecting the dual-band RF link, and broaden the use scenario. At the same time, in this embodiment, the first filter module includes: a band-stop filter structure, and the second filter module includes: a microstrip line; the band-stop filter structure is connected to the microstrip line, and the microstrip line is connected to the signal ground; the band-stop filter structure is used to transmit the first RF signal whose frequency is not within the first frequency band in the input signal to the microstrip line when receiving the input signal; the microstrip line is used to transmit the second RF signal whose frequency is not within the second frequency band in the first RF signal to the signal ground. In addition, the band-stop filter structure includes: a flat capacitor unit, the flat capacitor unit includes a first capacitor and a second capacitor, and the first capacitor and the second capacitor are respectively arranged in adjacent PCB layers; the flat capacitor unit is arranged between the microstrip line and the RF link. Compared with the existing technical means that require the additional use of grounding inductors or TVS tubes, this embodiment does not require any components and only requires the use of a special PCB copper foil configuration. Therefore, this embodiment can construct a low-cost RF protection device.

[0065] Reference Figure 4 , Figure 4 This is a schematic diagram of the third module of the radio frequency protection device of the utility model. Figure 1 The first embodiment of the radio frequency protection device is shown, and the second embodiment of the radio frequency protection device of the present utility model is proposed.

[0066] It is understandable that the above-mentioned technical solution of flat plate capacitor plus microstrip line still has the problem of complex structure, poor robustness, and relatively large RF loss. Therefore, in order to solve this problem, based on the above-mentioned first embodiment, the second embodiment of the RF protection device of the utility model is proposed. Figure 4 As shown, in this embodiment, the first filtering module 10 includes: a microstrip line 102; the second filtering module 20 includes: a filtering capacitor 202;

[0067] The microstrip line 102 is provided with a slot and a pad, and the filter capacitor 202 is fixed above the slot through the pad;

[0068] One end of the microstrip line 102 is connected to the RF link 1 , and the other end is connected to the signal ground 2 .

[0069] It should be noted that, in this embodiment, the first filtering module 10 may be a microstrip line 102. In this case, the microstrip line 102 may be arranged on the L1 layer of the PCB. Figure 5 , Figure 5 FIG. 1 is a top view of the structure of the microstrip line in the radio frequency protection device of the utility model, as shown in FIG. Figure 5 As shown, in this embodiment, a short and thick microstrip line 102 can be set on the L1 layer of the PCB board, and one end of the microstrip line 102 is connected to the above-mentioned RF link 1, thereby connecting to the RF link 1; the other end is connected to the reference ground copper foil of the L1 layer, that is, connected to the signal ground 2. A via can be set at the end of the ground microstrip line 102 to facilitate signal layer switching. At this time, the length of the microstrip line 102 can still be designed to be a length of 1 / 4 times the wavelength corresponding to the frequency of the first frequency band RF signal, so that the microstrip line 102 is open for the first frequency band RF signal. Its specific function and configuration are the same as those of the first embodiment, and will not be repeated here.

[0070] In order to reduce the complexity of the structure, in this embodiment, the second filter module 20 can be set as a filter capacitor 202. At the same time, in this embodiment, a groove can be formed on the microstrip line 102 structure, that is, the groove is formed, and a pad is also formed on the microstrip line 102. Figure 5 As shown, in this embodiment, the filter capacitor 202 can be fixed above the slot on the microstrip line 102 through a pad.

[0071] It should be understood that adding a filter capacitor 202 to the slot of the microstrip line 102 can be equivalent to the parasitic inductance L of the microstrip line 102 in parallel with the capacitor C, that is, the structure of the microstrip line 102 plus the filter capacitor 202 can also be equivalent to a band-stop filter. In this embodiment, the specifications and capacitance of the filter capacitor 202 can be adjusted to achieve an equivalent open circuit for the radio frequency signal in the second frequency band; in addition, the microstrip line 102 can be equivalent to an open circuit for the radio frequency signal in the first frequency band. Therefore, in this embodiment, based on the microstrip line 102 and the filter capacitor 202 placed after the slot on the microstrip line 102, the dual-band equivalent open circuit of the first frequency band and the second frequency band can also be achieved, and the structural complexity of the overall structure can be reduced.

[0072] It is easy to understand that, compared with the structure of a planar capacitor plus a microstrip line 102, the present embodiment can remove the design of the L2 layer and the L3 layer to reduce the complexity of the structure. However, after testing, it was found that this configuration still has the following problems: relatively large RF loss is introduced and a certain protection capability of the microstrip line 102 is lost.

[0073] Therefore, further, as an implementable embodiment, referring to Figure 6 , Figure 6 It is a schematic diagram of the fourth module of the radio frequency protection device of the utility model. In this embodiment, the second filtering module 20 further includes: a band-stop filtering structure 203;

[0074] One end of the band-stop filter structure 203 is connected to the microstrip line 102 , and the other end is connected to the signal ground 2 .

[0075] It should be understood that the band-stop filter structure 203 proposed in this embodiment can be arranged between the microstrip line 102 and the signal ground 2. In this case, the microstrip line 102 can be used to transmit the first RF signal in the input signal whose frequency is not within the first frequency band to the band-stop filter structure 203 when receiving the input signal. The band-stop filter structure 203 can be used to transmit the second RF signal in the first RF signal transmitted from the microstrip line 102 to the signal ground 2 whose frequency is not within the second frequency band to the signal ground 2, thereby realizing a dual-band equivalent open circuit of the first frequency band and the second frequency band.

[0076] Further, as an implementable embodiment, refer to Figure 7 , Figure 7 Schematic diagram of the fifth module of the radio frequency protection device of the utility model. In this embodiment, the band-stop filter structure 203 includes: a co-digital structure 203a, wherein the co-digital structure 203a is a serpentine-arranged slot;

[0077] The co-digital structure 203 a is disposed between the microstrip line 102 and the signal ground 2 .

[0078] It should be noted that if the microstrip line 102 is disposed on the L1 layer of the PCB board, the co-digital structure 203a may be disposed on the L3 layer in this embodiment. Figure 8 , Figure 8 FIG. 1 is a top view of the structure of the co-digital structure in the radio frequency protection device of the present utility model, as shown in FIG. Figure 8 As shown, in this embodiment, the interdigital structure 203a can be configured as a serpentine arrangement of slots. Fig. 9 Taking the dual-band protection effect of the microstrip line 102+cochin structure 203a as an example, Fig. 9 The schematic diagram of the microstrip line and the interdigital structure of the radio frequency protection device of the utility model is as follows: Fig. 9 As shown, assuming that the RF signal of the first frequency band will be transmitted through the microstrip line 102 of the L1 layer to the reference ground connected to the microstrip line 102, and will be switched to the L3 layer through the via (the L2 layer can be set with a forbidden layer). When the signal of the first frequency band passes through the co-chi structure 203a of the L3 layer, a part of the RF signal will bypass the co-chi structure 203a for transmission, which brings additional parasitic inductance; another part of the RF signal will be directly transmitted across the co-chi structure 203a, and the forbidden layer designed for the co-chi structure 203a will be equivalent to a capacitor. The above two transmission paths are parallel, that is, LC parallel, which is equivalent to a band-stop filter, that is, the co-chi structure 203a designed in this embodiment can be equivalent to a band-stop filter. In this embodiment, the size configuration of the co-chi structure 203a can be designed so that the operating frequency band of the equivalent band-stop filter is around the second frequency band, that is, the co-chi structure 203a can present a high impedance state to the second frequency band RF signal. Therefore, the second frequency band RF signal will choose a RF link with a smaller impedance for transmission, and will not pass through the microstrip line 102 to the ground and change layers to L3, so that the second frequency band RF signal can flow to the RF communication module 3 along the existing RF link.

[0079] In summary, in this embodiment, the transmission line theory can be used to design the length of the microstrip line 102 to be equivalent to the open circuit in the first frequency band, and the size of the co-indent structure 203a to be equivalent to the open circuit in the second frequency band. The two work together to achieve the dual-band equivalent open circuit of the first frequency band and the second frequency band. At this time, the dual-band RF signal will be transmitted along the RF link, thereby ensuring that the dual-band RF signal will not suffer a large loss due to the introduction of the protective device.

[0080] It should be understood that the band-stop filter equivalent to the above-mentioned co-digital structure 203a has the advantages of easy design and small RF loss. A proof test was carried out based on this configuration. At this time, the first frequency band can be 2.4G and the second frequency band can be 5G. The specific test results are as follows: Fig.10 As shown, Fig.10 This is a schematic diagram of the simulation waveform of the radio frequency protection device of the utility model. Fig.10In the figure, the solid line curve is the S11 value, which represents the reflection of the RF link; the dotted line curve is the S21 value, which represents the attenuation of the RF link. Fig.10 The waveform shows that the RF protection device shows small reflection (S11<-15dB) and small attenuation (S21>-0.5dB) in both 2.4G and 5G frequency bands, that is, the RF protection device has little impact on the RF link. It can be seen that the RF protection device designed based on the co-digital structure 203a not only realizes the equivalent open circuit of the dual-band 2.4G and 5G, but also has little impact on the RF link and will not affect the normal use of the product.

[0081] To sum up, the RF protector composed of the microstrip line 102 + co-chi structure 203a proposed in this embodiment can not only realize the equivalent open circuit of the dual-band, but also has little impact on the performance of the dual-band antenna. Compared with the protection device composed of the grounded inductor, it can greatly improve the protection ability of the protector against interference signals. At the same time, compared with the equivalent band-stop filter realized by the above-mentioned other configurations (flat capacitor structure and slotted filter capacitor 202, etc.), the RF protection device composed of the co-chi structure 203a has the advantages of strong robustness, easy design and adjustment, simple structure, and small introduced RF loss.

[0082] It should be understood that, based on the configuration of the RF protector proposed in this embodiment, if other configurations are used to replace the co-digital structure 203a, but the configuration is still equivalent to a band-stop filter, it still belongs to the protection scope of the utility model. In addition, the length of the microstrip line 102 remains unchanged, but the structure can also be designed by bending and the like according to the situation, and this embodiment does not limit this. At the same time, by fine-tuning the configuration, such as slotting around the co-digital structure 203a or slotting the microstrip line 102 (or microstrip line 201), the working frequency band of the protector is adjusted, which also belongs to the protection scope of this embodiment.

[0083] This embodiment discloses that the first filter module includes: a microstrip line; the second filter module includes: a filter capacitor; a slot and a pad are provided on the microstrip line, and the filter capacitor is fixed above the slot through the pad; one end of the microstrip line is connected to the RF link, and the other end is connected to the signal ground. Therefore, this embodiment can also realize the dual-band equivalent open circuit of the first frequency band and the second frequency band based on the microstrip line and the filter capacitor placed after the slot on the microstrip line, and reduce the complexity of the structure. In addition, the second filter module also includes: a band-stop filter structure; one end of the band-stop filter structure is connected to the microstrip line, and the other end is connected to the signal ground. The band-stop filter structure includes: a co-chi structure, the co-chi structure is a serpentine-arranged slot; the co-chi structure is arranged between the microstrip line and the signal ground. Compared with the prior art, the radio frequency protection device proposed in this embodiment can greatly improve the protection effect for surge signals and electrostatic signals. In addition, the RF protector composed of the microstrip line + co-chi structure proposed in this embodiment can not only realize the equivalent open circuit of the dual-band, but also has little impact on the performance of the dual-band antenna. At the same time, compared with the equivalent band-stop filter realized by the above-mentioned other configurations (flat capacitor structure and slotted filter capacitor, etc.), the RF protection device composed of the co-chi structure has the advantages of strong robustness, easy design and adjustment, simple structure, and small introduced RF loss.

[0084] To achieve the above object, the present invention also proposes a radio frequency protection system based on the above radio frequency protection device, referring to Fig.11 , Fig.11 This is the first structural block diagram of the radio frequency protection system of the utility model.

[0085] In this embodiment, the radio frequency protection system includes: an antenna interface 2, a radio frequency communication module 3 and the radio frequency protection device 4 mentioned above;

[0086] The antenna interface 2 is connected to the radio frequency communication module 3 via the radio frequency link 1;

[0087] One end of the radio frequency protection device 4 is connected to the radio frequency link 1 , and the other end is connected to the signal ground 2 .

[0088] It should be noted that, from the above-mentioned embodiment, it can be known that the above-mentioned radio frequency protection device 4 is connected to the signal ground 2, and can realize the dual-band equivalent open circuit of the first frequency band and the second frequency band. Therefore, when the external signal is input into the radio frequency link 1 through the antenna interface 2, it can be transmitted to the radio frequency communication module 3 through the radio frequency link 1. Among the signals transmitted on the radio frequency link 1, the interference signals (i.e., low-frequency surge signals and electrostatic signals) other than the radio frequency signals of the first frequency band and the second frequency band can all be released through the radio frequency protection device 4 to the signal ground 2, thereby realizing the protection of the radio frequency communication module 3 through the radio frequency protection device 4; at the same time, the radio frequency signals of the first frequency band and the second frequency band can still be input into the radio frequency communication module 3 along the original radio frequency link 1, thereby avoiding the introduction of large radio frequency link losses. Therefore, this embodiment proposes a radio frequency protection system that can realize low-loss dual-band radio frequency signal protection.

[0089] Further, as an implementable embodiment, refer to Fig.12 , Fig.12 It is a second structural block diagram of the radio frequency protection system of the utility model. In this embodiment, the radio frequency protection system further includes: a combiner 5;

[0090] The combiner 5 is arranged between the RF protection device 4 and the RF communication module 3 .

[0091] It should be understood that since the existing technology can only protect RF signals of a single frequency band, when there are RF signals of multiple frequency bands, the multiple RF signals need to be combined through the combiner 5 and then protected. Therefore, the existing RF protection device 4 is often arranged between the combiner 5 and the RF communication module 3. At this time, the input signal containing the interference signal input by the antenna interface 2 needs to pass through the combiner 5 before it can be discharged through the existing RF protector. Therefore, there is a risk of high-level surge signals directly damaging the combiner 5.

[0092] It is understandable that, since the RF protection device 4 proposed in the present application can simultaneously protect RF signals of multiple frequency bands, in the present embodiment, the combiner 5 can be arranged between the RF protection device 4 and the RF communication module 3, that is, the RF link 1 can be arranged between the antenna interface 2 and the combiner 5, and the RF signal input to the combiner 5 can be the filtered first RF signal and the second RF signal, so as to protect the combiner 5. Therefore, compared with a single microstrip line structure, the present embodiment can also simultaneously protect the combiner 5 and the RF link 1, further improving safety.

[0093] This embodiment discloses a radio frequency protection system, which includes: an antenna interface, a radio frequency communication module and a radio frequency protection device; the antenna interface is connected to the radio frequency communication module through a radio frequency link; one end of the radio frequency protection device is connected to the radio frequency link, and the other end is connected to the signal ground. In this embodiment, after the external wireless signal is input through the antenna interface, it can be transmitted to the radio frequency communication module through the radio frequency link, and in the signal transmitted on the radio frequency link, the interference signal (i.e., low-frequency surge signal and electrostatic signal) other than the first frequency band radio frequency signal and the second frequency band radio frequency signal can be released through the radio frequency protection device to the signal ground, so that the radio frequency communication module is protected by the radio frequency protection device; at the same time, the first frequency band radio frequency signal and the second frequency band radio frequency signal can still be input into the radio frequency communication module along the original radio frequency link, so as to avoid introducing a large radio frequency link loss. Therefore, this embodiment proposes a radio frequency protection system that can realize low-loss dual-band radio frequency signal protection. At the same time, the radio frequency protection system in this embodiment also includes: a combiner; the combiner is arranged between the radio frequency protection device and the radio frequency communication module. Therefore, compared with a single microstrip line structure, this embodiment can also simultaneously protect the combiner and the radio frequency link, further improving safety.

[0094] To achieve the above purpose, the utility model also proposes a radio frequency protection device, which includes the radio frequency protection system as described above. The specific structure of the radio frequency protection system refers to the above embodiment. Since the radio frequency protection system adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0095] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A radio frequency protection device, characterized in that: The radio frequency protection device comprises: a first filtering module and a second filtering module; The first filter module is connected to the radio frequency link and the second filter module respectively, and the second filter module is connected to the signal ground; The first filtering module is used for transmitting the first radio frequency signal in the input signal which is not within the first frequency band to the second filtering module when receiving the input signal, the input signal is input into the radio frequency link through the antenna interface, and the first filtering module is coupled to the radio frequency link; The second filtering module is used to transmit the second radio frequency signal whose frequency is not within the second frequency band in the first radio frequency signal to the signal ground.

2. The radio frequency protection device according to claim 1, characterized in that: The first filtering module includes: a band-stop filtering structure, and the second filtering module includes: a microstrip line; The band-stop filter structure is connected to the microstrip line, and the microstrip line is connected to the signal ground; The band-stop filter structure is used to transmit the first radio frequency signal in the input signal which is not within the first frequency band to the microstrip line when receiving the input signal; The microstrip line is used to transmit the second radio frequency signal whose frequency is not within the second frequency band in the first radio frequency signal to the signal ground.

3. The radio frequency protection device according to claim 2, characterized in that: The band-stop filter structure comprises: a flat capacitor unit, the flat capacitor unit comprises a first capacitor and a second capacitor, the first capacitor and the second capacitor are respectively arranged in adjacent PCB layers; The flat capacitor unit is arranged between the microstrip line and the radio frequency link.

4. The radio frequency protection device according to claim 1, characterized in that: The first filtering module includes: a microstrip line; the second filtering module includes: a filtering capacitor; The microstrip line is provided with a slot and a pad, and the filter capacitor is fixed above the slot through the pad; One end of the microstrip line is connected to the radio frequency link, and the other end is connected to the signal ground.

5. The radio frequency protection device according to claim 4, characterized in that: The second filtering module further includes: a band-stop filtering structure; One end of the band-stop filter structure is connected to the microstrip line, and the other end is connected to the signal ground.

6. The radio frequency protection device according to claim 5, characterized in that: The band-stop filter structure comprises: a co-digital structure, wherein the co-digital structure is a serpentine-arranged slot; The interdigital structure is arranged between the microstrip line and the signal ground.

7. A radio frequency protection system, characterized in that: The radio frequency protection system comprises: an antenna interface, a radio frequency communication module and a radio frequency protection device according to any one of claims 1 to 6; The antenna interface is connected to the radio frequency communication module via the radio frequency link; One end of the radio frequency protection device is connected to the radio frequency link, and the other end is connected to the signal ground.

8. The radio frequency protection system according to claim 7, characterized in that: The radio frequency protection system further includes: a combiner; The combiner is arranged between the radio frequency protection device and the radio frequency communication module.

9. A radio frequency protection device, characterized in that: The radio frequency protection device includes the radio frequency protection system described in claim 8.

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