A wideband frequency selective clipping system and radio frequency device
By using directional isolation and coupling-guided input coupling units and limiting components to process out-of-band signals, the high loss and large size problems of frequency selective limiters are solved, achieving low-loss and wide-bandwidth RF signal processing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SOUTHERN UNIVERSITY OF SCIENCE AND TECHNOLOGY
- Filing Date
- 2026-05-07
- Publication Date
- 2026-06-05
AI Technical Summary
In the prior art, frequency selective limiters cause high insertion loss and device size problems when expanding the effective operating bandwidth, mainly due to the power divider sharing the RF energy and the additional series filter.
By employing input coupling units and limiting components with directional isolation and coupling guidance capabilities, out-of-band signals are processed through reflection and cascading, avoiding the use of power dividers and filters, and forming an RF link to reduce loss and size.
It effectively reduces insertion loss, avoids the high loss and large size problems caused by additional filters, and expands the operating bandwidth.
Smart Images
Figure CN224329443U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of microwave radio frequency device technology, and in particular to a broadband frequency selective limiting system and radio frequency equipment. Background Technology
[0002] In complex electromagnetic environments, broadband frequency selective limiting systems serve as core passive protection components. They can allow small signals with power below a certain threshold to pass through with low loss, while selectively attenuating strong interference signals with power above the threshold, thereby protecting sensitive downstream microwave components from damage by high-power radio frequency signals.
[0003] In existing technologies, a power divider multi-path architecture is typically used to extend the total effective operating bandwidth of frequency selective limiters. Specifically, after the input broadband RF signal enters from the shared node, it is divided into multiple sub-signals by the power divider, and then fed into the branch links of the limiter corresponding to a specific frequency band. Simultaneously, to prevent RF signals from different sub-bands from flowing into other branches and causing crosstalk or multipath phase cancellation, an additional RF frequency selection device, such as a low-pass filter or band-pass filter, is usually connected in series in each limiter branch link to isolate and absorb out-of-band RF signals.
[0004] However, while the aforementioned existing technologies can extend the effective operating bandwidth, they still have the following shortcomings: Existing solutions use power dividers for direct node sharing and broadband signal splitting, resulting in the RF energy of the input signal being evenly distributed across all branch links regardless of its frequency. This means that branch links in specific frequency bands can only obtain a portion of the signal energy from the input end, and the insertion loss of the remaining branch links increases significantly. In addition, to suppress the RF signal overlap interference between the branch links of each limiter, additional RF filters are connected in series in the branch links. This not only further amplifies the dielectric attenuation loss and conductor loss of the system, worsening the overall insertion loss of the system, but also leads to a significant increase in the size and weight of microwave devices, making it difficult to meet the requirements of modern communication radar systems for miniaturization, lightweighting, and high integration of microwave passive devices.
[0005] This application aims to solve the problem of high insertion loss caused by the equal distribution of RF energy in existing branch links, and also to solve the problems of high loss and large size caused by adding additional RF filtering devices. Summary of the Invention
[0006] The main objective of this application is to provide a broadband frequency selective limiting system and radio frequency device, which aims to solve the high loss problem caused by the existing shared node multiplexing, while avoiding the high loss and large size problems caused by the introduction of frequency filters.
[0007] To achieve the above objectives, this application proposes a broadband frequency-selective limiting system, comprising:
[0008] The first input coupling unit has a system input terminal, a first output terminal, and a first isolation terminal;
[0009] The first limiting component is electrically connected to the first output terminal, and its signal passband is the first frequency band.
[0010] The second input coupling unit has a second input terminal and a second output terminal, and the second input terminal is electrically connected to the first isolation terminal of the first input coupling unit.
[0011] The second limiting component is electrically connected to the second output terminal, and its signal conduction frequency band is the second frequency band, which is located outside the band of the first frequency band;
[0012] The output synthesis unit is electrically connected to the output terminal of the first limiting component and also electrically connected to the output terminal of the second limiting component, and has a system output terminal.
[0013] Furthermore, the first limiting component includes a plurality of sub-limiters, the input terminals of the plurality of sub-limiters being electrically connected to the first output terminal of the first input coupling unit, and the output terminals of the plurality of sub-limiters being electrically connected to the output combining unit.
[0014] Furthermore, the first output terminal of the first input coupling unit includes a first through port and a first coupling port;
[0015] The first limiting component includes a first sub-limiter and a second sub-limiter;
[0016] The input terminal of the first sub-limiter is electrically connected to the first through port, and the output terminal is electrically connected to the output combining unit.
[0017] The input terminal of the second sub-limiter is electrically connected to the first coupling port, and the output terminal is electrically connected to the output synthesis unit.
[0018] Furthermore, the second limiting component includes a third sub-limiter and a fourth sub-limiter;
[0019] The input terminal of the third sub-limiter is electrically connected to the second output terminal of the second input coupling unit, and the output terminal is electrically connected to the output combining unit.
[0020] The input terminal of the fourth sub-limiter is electrically connected to the second output terminal of the second input coupling unit, and the output terminal is electrically connected to the output synthesis unit.
[0021] Furthermore, the second output terminal of the second input coupling unit includes a second through port and a second coupling port;
[0022] The input terminal of the third sub-limiter is electrically connected to the second through port;
[0023] The input terminal of the fourth sub-limiter is electrically connected to the second coupling port.
[0024] Furthermore, it also includes at least a third input coupling unit and a third limiting component;
[0025] The second input coupling unit further includes a second isolation terminal;
[0026] The third input coupling unit has a third input terminal and a third output terminal, and the third input terminal is electrically connected to the second isolation terminal.
[0027] The input terminal of the third limiting component is electrically connected to the third output terminal, and the output terminal is electrically connected to the output synthesis unit.
[0028] Furthermore, each of the sub-limiters includes:
[0029] A planar transmission line structure, used to transmit microwave signals and generate microwave magnetic fields;
[0030] A magnetic thin film covering at least one side of the planar transmission line structure;
[0031] The microwave magnetic field generated by the planar transmission line structure is coupled to the magnetic thin film.
[0032] Furthermore, the planar transmission line structure is selected from any one of coplanar waveguides, microstrip lines, and striplines.
[0033] Furthermore, when the planar transmission line structure is a coplanar waveguide, the planar transmission line structure includes:
[0034] Input connectors and output connectors;
[0035] The signal line has one end electrically connected to the input connector and the other end electrically connected to the output connector;
[0036] A metal layer is laid on both sides of the signal line and is on the same horizontal plane as the signal line.
[0037] This embodiment also discloses a radio frequency device, including the broadband frequency selective limiting system described above.
[0038] The above technical solution has the following advantages:
[0039] This application introduces a first input coupling unit and a second input coupling unit with directional isolation and coupling guidance capabilities between the system input and output terminals. It also employs a first and second limiting component with different passbands, along with an output combining unit, to form an RF link. This allows out-of-band microwave signals in the first frequency band to be reflected at the input port of the first limiting component, pass through the first isolation terminal of the first input coupling unit, and enter the second input coupling unit without loss. Finally, the signals flow out from the system output terminal of the output combining unit. This application solves the problem of high fixed distribution loss caused by power dividers in existing technologies by using the reflection of the first coupling unit and the first limiting component, as well as the cascading of the second coupling unit and the second limiting component. It also avoids the problems of increased size and deteriorated insertion loss caused by external filters, significantly reducing costs and expanding the effective operating bandwidth. Attached Figure Description
[0040] The present application will now be described in detail with reference to specific embodiments and accompanying drawings, wherein:
[0041] Figure 1 This is a structural block diagram of this application;
[0042] Figure 2 This is a schematic diagram of the structure of this application;
[0043] Figure 3 This is a structural diagram of the limiter in this application;
[0044] Figure 4 This is an exploded view of the limiter in this application.
[0045] In the diagram: 10, System input terminal; 20, First input coupling unit; 30, First limiting component; 31, First through port; 32, First sub-limiter; 33, First coupling port; 34, Second sub-limiter; 40, Output combining unit; 41, First output coupling unit; 42, Second output coupling unit; 50, Second input coupling unit; 60, Second limiting component; 61, Second through port; 62, Third sub-limiter; 63, Second coupling port; 64, Fourth sub-limiter; 70, System output terminal; 81, Input connector; 82, Upper housing; 83, Lower housing; 84, Output connector; 85, Transmission line; 86, Metal layer; 87, Magnetic thin film; 90, Third input coupling unit; 100, Third limiting component. Detailed Implementation
[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the following specific embodiments are merely illustrative of this application and do not constitute a limitation thereof.
[0047] In the fields of microwave radio frequency communication and radar detection under electromagnetic environments, broadband frequency selective limiting systems serve as core passive protection components. They must allow weak signals to pass through with low loss while selectively attenuating strong, high-power interference signals. In-depth research has revealed that existing solutions, in order to extend the total effective operating bandwidth of the frequency selective limiter, typically employ multiplexing or duplexer broadband limiting schemes. However, while these schemes can broaden the operating bandwidth, they also have some inherent problems that are difficult to solve, specifically:
[0048] Traditional solutions use power dividers at the input end for direct node sharing and signal splitting. This results in the RF signal being evenly distributed across all branches regardless of its frequency. This multi-path power splitting inevitably increases the insertion loss of the remaining branches, allowing links in specific frequency bands to only acquire a portion of the energy. Furthermore, to prevent multipath phase cancellation caused by out-of-band signal crosstalk, traditional solutions must additionally connect RF filters in series in each branch. This not only worsens the insertion loss of microwave signals but also significantly increases the size and weight of the devices.
[0049] Based on the above-mentioned technical problems, this application provides a broadband frequency selective limiting system and radio frequency equipment, which is mainly used to solve the technical problems of high loss and large size caused by the use of power dividers to distribute energy in the prior art.
[0050] like Figure 1 and Figure 2 As shown, this embodiment provides a broadband frequency selective limiting system, including a first input coupling unit 20, a first limiting component 30, a second input coupling unit 50, a second limiting component 60, and an output synthesis unit 40. The first input coupling unit 20 has a system input terminal 10, a first output terminal, and a first isolation terminal. The first limiting component 30 is electrically connected to the first output terminal, and its signal passband is a first frequency band. The second input coupling unit 50 has a second input terminal and a second output terminal, and the second input terminal is electrically connected to the first isolation terminal of the first input coupling unit 20. The second limiting component 60 is electrically connected to the second output terminal, and its signal passband is a second frequency band, which is outside the band of the first frequency band. The output synthesis unit 40 is electrically connected to the output terminal of the first limiting component 30 and also electrically connected to the output terminal of the second limiting component 60, and has a system output terminal 70.
[0051] In this embodiment, the first input coupling unit 20 includes a system input terminal 10, a first output terminal, and a first isolation terminal. It is primarily used to receive broadband microwave signals injected from an external antenna or pre-amplifier link, and to guide the signal flow without loss using inter-port electromagnetic wave coupling. As an optional implementation, the first input coupling unit 20 can be implemented using a microstrip broadband directional coupler printed on a dielectric substrate; alternatively, in scenarios requiring extremely high amplitude-phase consistency and isolation between different branches, the first input coupling unit 20 can be replaced with a 3dB quadrature hybrid bridge. Because the first input coupling unit 20 possesses excellent directional transmission characteristics, microwave signals entering from the system input terminal 10 can be directionally transmitted to the first output terminal with extremely low insertion loss, while effectively preventing direct leakage of microwave signals to the first isolation terminal, thus avoiding the full-band fixed power splitting loss caused by traditional power dividers.
[0052] The input terminal of the first limiting component 30 is electrically connected to the first output terminal, and its own signal passband is configured as a first frequency band (e.g., S-band, 2 to 4 GHz). As an optional embodiment of this application, the first limiting component 30 can be implemented using a ferrite-based magnetic surface wave limiter; or, in scenarios requiring a lower limiting level, a multi-stage PIN diode cascaded limiting circuit can be used. Since the matching passband of the first limiting component 30 is limited to the first frequency band, when a microwave signal containing the first frequency band is input, the microwave signal can penetrate the first limiting component 30 with extremely low attenuation; however, when there is an out-of-band signal outside the first frequency band (e.g., C-band, 4.0 to 8.0 GHz or X-band signal, 8 to 12 GHz), due to impedance mismatch, the out-of-band radio frequency energy outside the first frequency band will not be able to enter the interior of the first limiting component 30, but will be reflected at the input port of the first limiting component 30.
[0053] The second input coupling unit 50 is the main device for realizing energy recovery and lossless frequency division of microwave signals. As an optional implementation, the second input coupling unit 50 can also be a microstrip line directional coupler, or a three-dimensional stacked coupler can be used to save lateral physical space. In the actual physical connection, when the out-of-band microwave signal is reflected at the first limiting component 30, the reflected electromagnetic wave will be transmitted back to the first input coupling unit 20 along the first output terminal. Based on the reverse directional isolation mechanism of the first input coupling unit 20, the reflected microwave energy will not return to the system input terminal 10, but will be completely guided from the first isolation terminal to the second input terminal of the second input coupling unit 50. Thus, the first limiting component 30 is used as a reflective filter, so that the out-of-band signal can be completely separated without passing through any lossy power divider.
[0054] The signal conduction frequency band of the second limiting component 60 is configured as a second frequency band (e.g., X-band, 8 to 12 GHz), and the second frequency band is located outside the band of the first frequency band. The selection and implementation of the second limiting component 60 can refer to the first limiting component 30, and it is used to perform high-power limiting protection on the second frequency band signal reflected by the first limiting component 30 and entering through the second input coupling unit 50.
[0055] The output synthesis unit 40 can be a duplex synthesizer, such as Figure 2 As shown, a broadband directional coupler can also be used. In this embodiment, a duplex synthesizer is used as an example. It is used to combine two signals of different frequencies into one output. By setting the output synthesis unit 40, the first frequency band signal or the second frequency band signal after being processed by two different amplitude limiting paths can be re-converged into a single microwave signal and flow out from the system output terminal 70. This realizes the fusion of signals of different frequency bands in the spatial and temporal domains, which is convenient for single-port impedance matching with the subsequent radar receiver or communication baseband RF front end.
[0056] In this embodiment, the output synthesis unit 40 can be divided into a first output coupling unit 41 and a second output coupling unit 42. The input terminal of the first output coupling unit 41 is electrically connected to the first limiting component 30, and the input terminal of the second output coupling unit 42 is electrically connected to the second limiting component 60. The first output coupling unit 41 and the second output coupling unit 42 are also electrically connected to each other. When a microwave signal of the second frequency band enters the system input terminal 10, the microwave signal of the second frequency band will enter the second input coupling unit 50 through the first isolation terminal of the first input coupler. The second input coupling unit 50 then outputs the microwave signal of the second frequency band to the second limiting component 60, and after being attenuated by the second limiting component 60, it enters the second output coupling unit 42. Subsequently, the second output coupling unit 42 transmits the attenuated second frequency band microwave signal to the first output coupling unit 41. Finally, after being superimposed in parallel by the first output coupling units 41, the microwave signal is output from the system output terminal 70.
[0057] Therefore, this embodiment employs a first input coupling unit 20 and a second input coupling unit 50 with directional isolation and coupling guidance capabilities, and also uses a first limiting component 30 and a second limiting component 60 with different passbands, as well as an output combining unit 40 to form an RF link. This overcomes the high insertion loss caused by power dividers sharing energy in the prior art, and also prevents the high loss and large size defects caused by external frequency division filters.
[0058] like Figure 2As shown, in one embodiment of this application, the first limiting component 30 includes a plurality of sub-limiters, the input terminals of the plurality of sub-limiters are electrically connected to the first output terminal of the first input coupling unit 20, and the output terminals of the plurality of sub-limiters are electrically connected to the output synthesis unit 40.
[0059] The first limiting component 30 may include multiple parallel sub-limiters. In actual engineering implementation, the multiple sub-limiters are preferably a dual-path parallel limiting array containing two symmetrical branches; or a four-path orthogonal composite limiting array composed of four sub-limiters. The number of sub-limiters in this embodiment is not limited in detail. The number is adjusted according to the selection of the corresponding first input coupling unit 20. In this embodiment, the first limiting component 30 is decomposed into multiple sub-limiters, which improves the overall power tolerance of the system.
[0060] like Figure 1 and Figure 2 As shown, the first output terminal of the first input coupling unit 20 includes a first through port 31 and a first coupling port 33; the first limiting component 30 includes a first sub-limiter 32 and a second sub-limiter 34; the input terminal of the first sub-limiter 32 is electrically connected to the first through port 31, and the output terminal is electrically connected to the output combining unit 40; the input terminal of the second sub-limiter 34 is electrically connected to the first coupling port 33, and the output terminal is electrically connected to the output combining unit 40.
[0061] In practical implementation, the first sub-limiter 32 and the second sub-limiter 34 can be isomorphic devices with completely identical performance. The RF signals output from the first through port 31 and the first coupling port 33 have a 90-degree phase difference. When a high-power signal causes the first sub-limiter 32 and the second sub-limiter 34 to generate internal nonlinear reflections, the two reflected echoes undergo another 90-degree phase shift inside the first input coupling unit 20, accumulating to generate a 180-degree phase difference. This provides a smaller echo to the system input terminal 10, allowing signals outside the first frequency band to converge almost without loss to the first isolation terminal and enter the second input coupling unit 50 through the first isolation terminal.
[0062] like Figure 1 and Figure 2 As shown, the second limiting component 60 includes a third sub-limiter 62 and a fourth sub-limiter 64; the input terminal of the third sub-limiter 62 is electrically connected to the second output terminal of the second input coupling unit 50, and the output terminal is electrically connected to the output combining unit 40; the input terminal of the fourth sub-limiter 64 is electrically connected to the second output terminal of the second input coupling unit 50, and the output terminal is electrically connected to the output combining unit 40.
[0063] The second output terminal of the second input coupling unit 50 includes a second through port 61 and a second coupling port 63; the input terminal of the third sub-limiter 62 is electrically connected to the second through port 61; and the input terminal of the fourth sub-limiter 64 is electrically connected to the second coupling port 63.
[0064] In some embodiments, the number of sub-limiters in this embodiment can be multiple. Preferably, a third sub-limiter 62 and a fourth sub-limiter 64 are used in this preferred embodiment, and their number is selected based on the type of the second input coupling unit 50. This embodiment ensures that the second frequency band signal extracted from the first isolation terminal can achieve high power carrying capacity and high-precision VSWR by connecting the third sub-limiter 62 and the fourth sub-limiter 64 to the second through port 61 and the second coupling port 63, respectively.
[0065] like Figure 1 As shown, in one embodiment of this application, this embodiment further includes at least a third input coupling unit 90 and a third limiting component 100; the second input coupling unit 50 further includes a second isolation terminal; the third input coupling unit 90 has a third input terminal and a third output terminal, the third input terminal being electrically connected to the second isolation terminal; the input terminal of the third limiting component 100 is electrically connected to the third output terminal, and the output terminal is electrically connected to the output combining unit 40.
[0066] Building upon the above embodiments, this embodiment also possesses the advantage of better bandwidth expansion. Specifically, based on the above embodiments, to achieve the increased bandwidth with minimal modifications, this embodiment further introduces a third input coupling unit 90 and a third limiting component 100. Of course, this embodiment can also continuously connect more coupling units and limiting units, such as extending the third input coupling unit 90 to include a fourth input coupling unit and a fourth limiting component, a fifth input coupling unit and a fifth limiting component, etc. These will not be repeated here; only one expansion method is listed. In practical engineering, the first limiting component 30 corresponds to the first frequency band, the second limiting component 60 corresponds to the second frequency band, and correspondingly, the third limiting component 100 corresponds to the third frequency band. In this embodiment, the first, second, and third frequency bands can correspond to the S-band, C-band, and X-band, respectively; or to the L-band, Ku-band, and Ka-band, respectively. When a signal from the third frequency band is input, it will undergo two consecutive reflections at the ports of the first limiting component 30 and the second limiting component 60, ultimately entering the third limiting component 100 from the second isolation terminal. This embodiment achieves an extension scheme of the operating frequency band to any target bandwidth without introducing the series insertion loss of the preceding stage. Ultimately, it can broaden the RF signal (i.e., small signal) with power below the limiter threshold power, while attenuating the RF signal (i.e., large signal) with power above the limiter threshold power.
[0067] like Figures 1 to 4 As shown, in one embodiment of this application, each of the sub-limiters includes a planar transmission line 85 structure for transmitting microwave signals and generating a microwave magnetic field; and a magnetic thin film 87 covering at least one side of the planar transmission line 85 structure; wherein the microwave magnetic field generated by the planar transmission line 85 structure is coupled to the magnetic thin film 87.
[0068] In some embodiments, the magnetic thin film 87 of this embodiment can be a yttrium iron garnet (YIG) epitaxial thin film. A bias magnetic field is applied outside the sub-limiter using a permanent magnet to excite the spin wave of the magnetic thin film 87. The microwave magnetic field generated by the planar transmission line 85 structure is strongly coupled to the magnetic thin film 87. When the input microwave power exceeds the critical threshold for spin wave excitation of the thin film material, the electromagnetic energy converts the high-power microwave signal into a static magnetic wave and dissipates it in the form of lattice thermal vibration, while ensuring that the sub-limiter allows low-loss passage of small signals.
[0069] like Figure 3 and Figure 4 As shown, the planar transmission line 85 structure is selected from any one of coplanar waveguides, microstrip lines, and striplines.
[0070] In some embodiments, the following is one implementation of the sub-limiter exemplified in this example. Specifically, the sub-limiter includes an upper housing 82 and a lower housing 83. The upper housing 82 and the lower housing 83 are used to lock the planar transmission line 85 structure and the magnetic film 87. The magnetic film 87 can be disposed on one side or both sides of the planar transmission line 85 structure, so that the microwave signal generated by the planar transmission line 85 structure can be coupled to the magnetic film 87 on one or both sides, thereby dissipating the high-power microwave signal in the form of a spin wave; improving the contact strength between the magnetic film 87 and the planar transmission line 85 structure; in addition, the middle part of the upper housing 82 and the lower housing 83 in this embodiment is hollowed out to expose the corresponding magnetic film 87, thereby increasing the heat dissipation area of the magnetic film 87 and also achieving weight reduction.
[0071] like Figure 3 and Figure 4 As shown, in one embodiment of this application, when the planar transmission line 85 structure is a coplanar waveguide, the planar transmission line 85 structure includes an input connector 81, an output connector 84, a signal line, and a metal layer 86; one end of the signal line is electrically connected to the input connector 81, and the other end is electrically connected to the output connector 84; the metal layer 86 is laid on both sides of the signal line and is on the same horizontal plane as the signal line.
[0072] When the planar transmission line 85 structure is preferably a coplanar waveguide (CPW), the input connector 81 and output connector 84 can be SMA coaxial RF connectors or SMP blind-mating RF connectors. The input connector 81 and output connector 84 are respectively mounted on the opposite side walls of the upper housing 82 and the lower housing 83, so that the signal lines are connected from the input connector 81 and connected to the output connector 84 on the planar transmission line 85 structure according to a predetermined trajectory. The signal lines can be connected from the input connector 81 to the output connector 84 in a straight line, or they can be connected to the output connector 84 in a broken line, coupling line, or other manner. In this embodiment, the metal layer 86 is preferably a ground layer. Through the layout structure of the coplanar waveguide in this embodiment, the microwave alternating magnetic field can be highly densely confined on the surface of the planar transmission line 85 structure, which improves the coupling efficiency between the magnetic field and the magnetic thin film 87 covering it, reduces the critical power threshold of nonlinear spin wave excitation, and accelerates the limiting response speed.
[0073] In this embodiment, the metal layer 86 has a gradient structure at both the input and output ends of the signal line. The purpose of this structure is to compensate for the wave impedance change caused by the loading of the magnetic thin film 87, so that the microwave signal will not be severely reflected when it enters the signal line, thereby optimizing the bandwidth matching.
[0074] This application also discloses a radio frequency device including the aforementioned broadband frequency selective limiting system.
[0075] In practical applications, the radio frequency (RF) equipment can be the receiver front-end of a broadband phased array radar; or it can be an electronic countermeasures (ECM) pod mounted on a drone. By integrating the aforementioned broadband frequency selection and limiting system into the RF equipment, the device can limit large signal pulses even when receiving weak microwave signals, while also limiting them in complex full-band electromagnetic interference environments, thus ensuring the safety of the subsequent low-noise amplifiers and RF mixers.
[0076] The embodiments of this application are mainly used for bandwidth expansion of small signals. The first limiting component 30, the second limiting component 60, and the third limiting component 100 all employ single-band static magnetic surface limiters. A uniform bias magnetic field is applied externally using a permanent magnet to excite the self-selected wave. Simultaneously, the first input coupling unit 20, the second input coupling unit 50, and the third input coupling unit 90 are cascaded, eliminating the need for complex magnetic circuit design in existing multiplexers or design considerations for material properties. This can be achieved using mature microwave devices. When a microwave signal is input, this application utilizes the first limiting component 30... The reflection characteristics of 0, combined with the directional isolation characteristics of the first input coupling unit 20, allow out-of-band microwave signals to be injected losslessly from the first isolation terminal into the second input coupling unit 50 and into the second limiting component 60. This eliminates the need for additional RF filters on the link. Microwave signals from each frequency band are processed by their respective links and then converged by the output synthesis unit 40 to the system output terminal 70. Furthermore, this embodiment achieves an extension scheme of the operating frequency band to any target bandwidth without introducing the series insertion loss of the preceding stage. Ultimately, it can broaden small signals and attenuate large signals, greatly reducing the manufacturing and debugging costs of the device.
[0077] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.
Claims
1. A broadband frequency-selective limiting system, characterized in that, include: The first input coupling unit has a system input terminal, a first output terminal, and a first isolation terminal; The first limiting component is electrically connected to the first output terminal, and its signal passband is the first frequency band. The second input coupling unit has a second input terminal and a second output terminal, and the second input terminal is electrically connected to the first isolation terminal of the first input coupling unit. The second limiting component is electrically connected to the second output terminal, and its signal conduction frequency band is the second frequency band, which is located outside the band of the first frequency band; The output synthesis unit is electrically connected to the output terminal of the first limiting component and also electrically connected to the output terminal of the second limiting component, and has a system output terminal.
2. The broadband frequency selective limiting system as described in claim 1, characterized in that, The first limiting component includes multiple sub-limiters, the input terminals of the multiple sub-limiters are electrically connected to the first output terminal of the first input coupling unit, and the output terminals of the multiple sub-limiters are electrically connected to the output combining unit.
3. The broadband frequency selective limiting system as described in claim 2, characterized in that, The first output terminal of the first input coupling unit includes a first through port and a first coupling port; The first limiting component includes a first sub-limiter and a second sub-limiter; The input terminal of the first sub-limiter is electrically connected to the first through port, and the output terminal is electrically connected to the output combining unit. The input terminal of the second sub-limiter is electrically connected to the first coupling port, and the output terminal is electrically connected to the output synthesis unit.
4. The broadband frequency selective limiting system as described in any one of claims 1 to 3, characterized in that, The second limiting component includes a third sub-limiter and a fourth sub-limiter; The input terminal of the third sub-limiter is electrically connected to the second output terminal of the second input coupling unit, and the output terminal is electrically connected to the output combining unit. The input terminal of the fourth sub-limiter is electrically connected to the second output terminal of the second input coupling unit, and the output terminal is electrically connected to the output synthesis unit.
5. The broadband frequency selective limiting system as described in claim 4, characterized in that, The second output terminal of the second input coupling unit includes a second through port and a second coupling port; The input terminal of the third sub-limiter is electrically connected to the second through port; The input terminal of the fourth sub-limiter is electrically connected to the second coupling port.
6. The broadband frequency selective limiting system as described in any one of claims 1 to 3, characterized in that, It also includes at least a third input coupling unit and a third limiting component; The second input coupling unit further includes a second isolation terminal; The third input coupling unit has a third input terminal and a third output terminal, and the third input terminal is electrically connected to the second isolation terminal. The input terminal of the third limiting component is electrically connected to the third output terminal, and the output terminal is electrically connected to the output synthesis unit.
7. The broadband frequency selective limiting system as described in claim 2, characterized in that, Each of the sub-limiters includes: A planar transmission line structure, used to transmit microwave signals and generate microwave magnetic fields; A magnetic thin film covering at least one side of the planar transmission line structure; The microwave magnetic field generated by the planar transmission line structure is coupled to the magnetic thin film.
8. The broadband frequency selective limiting system as described in claim 7, characterized in that, The planar transmission line structure is selected from any one of coplanar waveguides, microstrip lines, and striplines.
9. The broadband frequency selective limiting system as described in claim 7 or 8, characterized in that, When the planar transmission line structure is a coplanar waveguide, the planar transmission line structure includes: Input connectors and output connectors; The signal line has one end electrically connected to the input connector and the other end electrically connected to the output connector; A metal layer is laid on both sides of the signal line and is on the same horizontal plane as the signal line.
10. A radio frequency device, characterized in that, Includes the broadband frequency selective limiting system as described in any one of claims 1 to 9.