A frequency selective limiter and radio frequency device

Abstract

The application discloses a frequency selective amplitude limiter and a radio frequency device, and relates to the technical field of microwave radio frequency devices. Specifically, the frequency selective amplitude limiter comprises a planar transmission line structure, a first magnetic film and a second magnetic film. The planar transmission line structure is used for transmitting a microwave radio frequency signal and generating a microwave magnetic field. The first magnetic film covers a first surface of the planar transmission line structure. The second magnetic film covers a second surface of the planar transmission line structure, so that the planar transmission line structure is clamped between the first magnetic film and the second magnetic film. The microwave magnetic field generated by the planar transmission line structure is coupled to the first magnetic film and the second magnetic film at the same time. The first surface and the second surface of the planar transmission line structure are covered by the first magnetic film and the second magnetic film respectively, so that the magnetic coupling efficiency can be improved without greatly increasing the interaction length, and the frequency selective amplitude limiter also has a very low nonlinear starting threshold and a very low insertion loss.

Description

Technical Field

[0001] This application relates to the field of microwave radio frequency device technology, and in particular to a frequency selective limiter and radio frequency equipment. Background Technology

[0002] Frequency selective limiters (FSLs) utilize the spin wave nonlinear effect in ferrite materials such as yttrium iron garnet (YIG) to automatically attenuate signals above a threshold under strong electromagnetic interference environments, while allowing weak signals to pass through with low loss.

[0003] In the traditional construction of frequency-selective limiters, specific electromagnetic field guiding and coupling structures are typically required to achieve energy exchange between microwave signals and spin waves in magnetic thin films. However, existing technologies still face some technical challenges in pursuing low limiting thresholds, wide operating bandwidths, and miniaturized integration.

[0004] Currently, existing energy conversion interfaces have low coupling efficiency between electromagnetic waves and magnetic thin films, and microwave signals cannot be fully excited and converted into spin waves within a unit length. In order to achieve the preset amplitude limiting depth or further reduce the amplitude limiting threshold, existing technologies will significantly extend the interaction length between microwave signals and magnetic thin films to accumulate sufficient nonlinear effects.

[0005] However, the aforementioned existing technologies increase the interaction length between the microwave signal and the magnetic thin film, thereby increasing the insertion loss. The high insertion loss is proportionally added to the overall noise figure, weakening the receiver's sensitivity. This makes the system prone to signal submersion or distortion when faced with weak effective signals, making it difficult to effectively capture and demodulate them. At the same time, the long interaction path also leads to excessively long device dimensions, which not only significantly increases manufacturing costs but also introduces additional parasitic parameters, leading to the risk of electromagnetic crosstalk between circuits.

[0006] Therefore, there is an urgent need for a new type of frequency-selective limiter structure that can achieve efficient coupling between electromagnetic waves and spin waves, while reducing insertion loss, manufacturing cost and size. Utility Model Content

[0007] The main objective of this application is to provide a frequency selective limiter and radio frequency device, which aims to solve the problem of low underlying coupling efficiency between electromagnetic waves and spin waves, as well as the problems of increased device insertion loss, cost, and size.

[0008] To achieve the above objectives, this application proposes a frequency-selective limiter, comprising:

[0009] A planar transmission line structure, used to transmit microwave radio frequency signals and generate microwave magnetic fields;

[0010] A first magnetic thin film covers the first surface of the planar transmission line structure;

[0011] A second magnetic film covers the second surface of the planar transmission line structure, such that the planar transmission line structure is sandwiched between the first magnetic film and the second magnetic film.

[0012] The microwave magnetic field generated by the planar transmission line structure is simultaneously coupled to the first magnetic thin film and the second magnetic thin film;

[0013] The planar transmission line structure includes signal lines, and the signal lines include:

[0014] The first signal segment extends inward from one side of the planar transmission line structure;

[0015] The third signal segment extends inward from the other side of the planar transmission line structure;

[0016] One or more second signal segments are located between the first signal segment and the third signal segment;

[0017] The widths of the first signal segment and the third signal segment are both gradually changing, or the first signal segment, one or more second signal segments, and the third signal segment are arranged alternately and interleaved.

[0018] Furthermore, the signal line is arranged along the transmission direction of the microwave radio frequency signal;

[0019] The signal line radiates a first magnetic field to the first surface of the planar transmission line structure and also radiates a second magnetic field to the second surface of the planar transmission line structure.

[0020] The first magnetic field and the second magnetic field are coupled to the first magnetic thin film and the second magnetic thin film, respectively.

[0021] Furthermore, the first magnetic thin film and the second magnetic thin film respectively contact the first and second surfaces of the planar transmission line structure to establish spin wave excitation regions on both the first and second surfaces of the planar transmission line structure.

[0022] Furthermore, the planar transmission line structure also includes:

[0023] A metal layer that cooperates with the signal line to guide the transmission of the microwave radio frequency signal;

[0024] The planar transmission line structure formed by the signal line and the metal layer is selected from any one of coplanar waveguides, microstrip lines, or striplines.

[0025] Furthermore, when the planar transmission line structure is a coplanar waveguide;

[0026] The signal line extends from one side of the planar transmission line structure to the other side and is attached between the first magnetic film and the second magnetic film;

[0027] The metal layer is located around the signal line and is attached between the first magnetic film and the second magnetic film.

[0028] Furthermore, a heat sink or a non-magnetic substrate is provided on the side of the first magnetic thin film away from the planar transmission line structure;

[0029] And / or, the side of the second magnetic thin film away from the planar transmission line structure is provided with a non-magnetic substrate or heat sink.

[0030] Furthermore, when the planar transmission line structure is a microstrip line;

[0031] The signal line is attached between the first magnetic film and the second magnetic film;

[0032] The metal layer is attached to the side of the first magnetic film facing away from the signal line.

[0033] This application also discloses a radio frequency device, which includes the frequency selective limiter described above.

[0034] The above technical solution has the following advantages:

[0035] This application addresses the shortcomings of traditional single-sided loaded structures by covering the first and second surfaces of a planar transmission line structure with a first magnetic thin film and a second magnetic thin film, respectively. This allows the microwave radio frequency magnetic field generated by the planar transmission line structure to radiate simultaneously in the entire space, both upwards and downwards, and to be absorbed by the first and second magnetic thin films on both sides. This solves the problems of significant energy waste of microwave magnetic field on the air side and low coupling efficiency on the bottom layer in traditional single-sided loaded structures. It avoids the submersion or distortion of weak signals, eliminates the need to significantly increase the interaction length to improve magnetic coupling efficiency, and also features an extremely low nonlinear oscillation threshold and extremely low insertion loss. It reduces the interaction path between the microwave signal and the magnetic thin film, thereby reducing manufacturing costs and lowering the risk of electromagnetic crosstalk between circuits. Attached Figure Description

[0036] The present application will now be described in detail with reference to specific embodiments and accompanying drawings, wherein:

[0037] Figure 1 This is a structural diagram of one embodiment of this application;

[0038] Figure 2 This is a structural diagram of a planar transmission line structure according to one embodiment of this application;

[0039] Figure 3 This is a structural diagram of another embodiment of this application;

[0040] Figure 4 This is a structural diagram of a planar transmission line structure in another embodiment of this application.

[0041] In the figure: 10, input port; 20, planar transmission line structure; 21, signal line; 22, first signal segment; 23, second signal segment; 24, third signal segment; 30, first magnetic thin film; 40, second magnetic thin film; 50, metal layer; 60, output port; 70, heat sink. Detailed Implementation

[0042] 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.

[0043] In existing technologies, frequency selective limiters often employ a planar transmission line structure 20, with a magnetic thin film loaded on one side of the planar transmission line structure 20. Since the microwave magnetic field around the microwave transmission line is distributed in a ring-shaped space, a large amount of magnetic field energy on the other side of the transmission line is in the air medium. The microwave magnetic field in the air cannot penetrate into the magnetic thin film and participate in the excitation of spin waves, resulting in low magnetic coupling efficiency of the microwave magnetic field. This leads RF designers to introduce resonant loops in the circuit or increase the interaction length of the transmission line, which in turn results in limited operating bandwidth of the device or a significant increase in overall insertion loss.

[0044] Therefore, this application maximizes the magnetic coupling efficiency of the microwave magnetic field around the transmission line on the planar transmission line structure 20, thereby solving the problem of low underlying coupling efficiency between electromagnetic waves and spin waves in the present invention, and also solving the problem of increased device insertion loss.

[0045] Before describing the various embodiments, some common technical terms used in this application will be explained and described:

[0046] Planar transmission line structure 20 refers to a conductor for microwave radio frequency signals fabricated on a planar medium by photolithography, etching or thin film deposition processes.

[0047] Magnetic thin film refers to a material layer that can generate static magnetic waves or spin waves under the bias of an external DC magnetic field, such as yttrium iron garnet (YIG) single crystal thin film. In this application, the first magnetic thin film 30 and the second magnetic thin film 40 are selected together to constitute the limiter of this application.

[0048] The specific embodiments of this application are described below with reference to the accompanying drawings and the various claims.

[0049] like Figure 1 and Figure 3 As shown in one embodiment of this application, a frequency selective limiter is disclosed, including a planar transmission line structure 20, a first magnetic thin film 30, and a second magnetic thin film 40. The planar transmission line structure 20 is used to transmit microwave radio frequency signals and generate a microwave magnetic field. The first magnetic thin film 30 covers a first surface of the planar transmission line structure 20. The second magnetic thin film 40 covers a second surface of the planar transmission line structure 20, so that the planar transmission line structure 20 is sandwiched between the first magnetic thin film 30 and the second magnetic thin film 40.

[0050] The microwave magnetic field generated by the planar transmission line structure 20 is simultaneously coupled to the first magnetic thin film 30 and the second magnetic thin film 40.

[0051] like Figure 1 and Figure 3 As shown, in some embodiments, the planar transmission line structure 20 is located in the middle. In this embodiment, the upper part of the planar transmission line structure 20 is preferably defined as the first surface and the lower part as the second surface. Of course, this selection can be adjusted as needed. The above only represents one implementation method of this embodiment. The following description is based on the limitation method of this embodiment. Specifically, the first magnetic film 30 is disposed above the planar transmission line structure 20 and covers the first surface of the planar transmission line structure 20; the second magnetic film 40 is disposed below the planar transmission line structure 20 and covers the second surface of the planar transmission line structure 20. Therefore, in this embodiment, the sandwich structure is realized by using the first magnetic film 30, the planar transmission line structure 20 and the second magnetic film 40 from top to bottom.

[0052] When microwave radio frequency signals are transmitted in the planar transmission line structure 20, the planar transmission line structure 20 continuously generates an alternating microwave magnetic field, which radiates to the first and second surfaces of the planar transmission line structure 20. Since the upper and lower sides of the planar transmission line structure 20 are covered by the first magnetic thin film 30 and the second magnetic thin film 40, respectively, the microwave magnetic field can simultaneously penetrate into the interior of the first magnetic thin film 30 and the second magnetic thin film 40. Compared to the original limiter where the microwave magnetic field penetrates on one side and is exposed on the other, this embodiment achieves magnetic field flux capture on both the upper and lower sides of the planar transmission line structure 20, thereby significantly reducing the power threshold of spin wave nonlinear oscillation without the need for an external matching resonator.

[0053] It should be noted that in this embodiment, the first magnetic film 30 and the second magnetic film 40 can directly contact and adhere to the upper and lower sides of the planar transmission line structure 20, as described in the following embodiment; the first magnetic film 30 and the second magnetic film 40 can also indirectly contact and adhere to the upper and lower sides of the planar transmission line structure 20, such as when a nanoscale metal transition buffer layer, such as titanium or chromium, is sandwiched between the first magnetic film 30 and the second magnetic film 40. This buffer layer is mainly used to bridge the planar transmission line structure 20 and the yttrium iron garnet lattice. In this embodiment, the conductor of the planar transmission line structure 20 is copper.

[0054] High-power limiting in the microwave band generates severe local heat dissipation. The thermal expansion coefficients of the conductor and the magnetic thin film in the planar transmission line structure 20 differ significantly, making them highly susceptible to interlayer shear stress during thermal cycling, leading to blistering and delamination between the magnetic thin film and the planar transmission line structure 20. Therefore, the titanium or chromium metal transition buffer layer provided in this embodiment, with a lattice constant and thermal expansion coefficient between the conductor and the magnetic thin film of the planar transmission line structure 20, forms a stress gradient release region to mitigate the blistering and delamination problem.

[0055] like Figure 1 and Figure 3 As shown, in one embodiment of this application, the planar transmission line structure 20 includes a signal line 21, which is arranged along the transmission direction of the microwave radio frequency signal; the signal line 21 radiates a first magnetic field to a first surface of the planar transmission line structure 20 and a second magnetic field to a second surface of the planar transmission line structure 20; the first magnetic field and the second magnetic field are respectively coupled to the first magnetic thin film 30 and the second magnetic thin film 40.

[0056] In some embodiments, signal line 21 serves as a conductor of planar transmission line structure 20, acting as a transmission channel for microwave radio frequency signals. Its interior is used to carry high-frequency alternating current. The high-frequency alternating current flowing through signal line 21 radiates magnetic field lines perpendicular to signal line 21, thereby forming a microwave magnetic field. The portion of the microwave magnetic field radiating towards the first surface of planar transmission line structure 20 constitutes the first magnetic field, and the portion radiating towards the second surface constitutes the second magnetic field. Therefore, the microwave magnetic field is mainly divided into a first magnetic field and a second magnetic field. The first magnetic field penetrates upwards into the lattice of the first magnetic thin film 30, and the second magnetic field penetrates downwards into the lattice of the second magnetic thin film 40. This causes the microwave magnetic fields radiated on the upper and lower sides of planar transmission line structure 20 to be converted into spin wave energy in the corresponding first magnetic thin film 30 and second magnetic thin film 40, respectively, achieving full coupling on both sides and improving the limiter's absorption and limiting capability for high-power electromagnetic pulses.

[0057] like Figure 1 and Figure 3As shown, in one embodiment of this application, the first magnetic thin film 30 and the second magnetic thin film 40 respectively contact the first surface and the second surface of the planar transmission line structure 20 to establish spin wave excitation regions on both the first surface and the second surface of the planar transmission line structure 20.

[0058] In some embodiments, this embodiment is an explanation of the above embodiments, that is, the first magnetic film 30 and the second magnetic film 40 can directly contact and adhere to the upper and lower sides of the planar transmission line structure 20. In this embodiment, the buffer layer is removed from the contact surface between the first magnetic film 30 and the second magnetic film 40 and the planar transmission line structure 20, eliminating the medium interference between them, so that the first magnetic film 30 and the second magnetic film 40 are directly glued to the planar transmission line structure 20, further increasing the coupling strength of the microwave magnetic field between the first magnetic film 30 and the second magnetic film 40.

[0059] like Figures 1 to 4 As shown, in one embodiment of this application, the planar transmission line structure 20 further includes a metal layer 50, which cooperates with the signal line 21 to guide the transmission of the microwave radio frequency signal; the planar transmission line structure 20 formed by the signal line 21 and the metal layer 50 is selected from any one of coplanar waveguide, microstrip line or stripline.

[0060] In some embodiments, the planar transmission line structure 20 mainly includes a signal line 21 and a metal layer 50. The signal line 21 is mainly used to carry high-frequency radio frequency signals, and the metal layer 50 is used for grounding, mainly providing a reference return potential. Together, they form a circuit for microwave radio frequency signals. The positional relationship between the metal layer 50 and the signal line 21 in this embodiment is not limited, but different positional distributions between the metal layer 50 and the signal line 21 result in different radio frequency signal transmission modes in space. This embodiment is compatible with various microwave transmission line types. Depending on the board-level interface of the specific radar receiver or communication radio frequency front-end module, coplanar waveguides, microstrip lines, or striplines can be flexibly selected. The microstrip line can be a microstrip line connected by ordinary wires or a coupled microstrip line. Different line type combinations provide different microwave magnetic field distribution dispersion characteristics to adapt to the operating requirements of different frequency bands.

[0061] like Figure 3 and Figure 4 As shown, specifically, when the planar transmission line structure 20 is a coplanar waveguide; the signal line 21 extends from one side of the planar transmission line structure 20 to the other side and is attached between the first magnetic thin film 30 and the second magnetic thin film 40; the metal layer 50 is located on both sides of the signal line 21 and is attached between the first magnetic thin film 30 and the second magnetic thin film 40.

[0062] In some embodiments, when the planar transmission line structure 20 is a coplanar waveguide, the signal line 21 is located at the center of the cross-section of the planar transmission line structure 20, causing the metal layer 50 to be divided into two parts, which are arranged parallel to each other on both sides of the outer periphery of the signal line 21 as ground reference surfaces, such as... Figure 4 As shown. In this embodiment, the signal line 21 and the two metal layers 50 are on the same horizontal plane, and the upper surfaces of both the signal line 21 and the metal layers 50 are attached to the first magnetic film 30, and the lower surfaces are attached to the second magnetic film 40. During the microwave radio frequency signal transmission, the radio frequency signal is transmitted from one end of the signal line 21 to the other end. The signal line 21 generates an alternating microwave magnetic field under the condition of the microwave radio frequency signal. The microwave magnetic field is mainly concentrated in the gap area between the signal line 21 and the metal layer 50. Under the clamping action of the first magnetic film 30 and the second magnetic film 40, the microwave magnetic field between the signal line 21 and the metal layer 50 is completely confined inside the planar transmission line structure 20, avoiding the microwave magnetic field from radiating to the external space, thereby reducing radiation loss.

[0063] like Figure 1 , Figure 3 and Figure 4 As shown, the signal line 21 further includes a first signal segment 22, a second signal segment 23, and a third signal segment 24. The first signal segment 22 extends inward from one side of the planar transmission line structure 20; the third signal segment 24 extends inward from the other side of the planar transmission line structure 20; the second signal segment 23 connects the first signal segment 22 and the third signal segment 24; wherein the widths of the first signal segment 22 and the third signal segment 24 are both gradually changing, forming an impedance matching transition section.

[0064] In some embodiments, signal line 21 is divided into three functional regions along the transmission path of microwave radio frequency signals. The first signal segment 22 connects to the input port 10 to introduce external antenna signals. The third signal segment 24 connects to the output port 60 to output the limited signal. The second signal segment 23, located in the middle, is the core region for nonlinear absorption by the high-frequency magnetic field. The widths of the first signal segment 22 and the third signal segment 24 have a gradually changing structure, from... Figure 4 As can be seen, the width of the first signal segment 22 and the third signal segment 24 gradually converges smoothly from the edge inward. The purpose is to compensate for the wave impedance change caused by the loading of the first magnetic thin film 30 and the second magnetic thin film 40, so that the microwave radio frequency signal will not be severely reflected when it enters the second signal segment 23, thereby optimizing the bandwidth matching.

[0065] like Figure 3 and Figure 4As shown, in one embodiment of this application, the first magnetic thin film 30 is provided with a heat sink 70 or a non-magnetic substrate on the side facing away from the planar transmission line structure 20; and / or, the second magnetic thin film 40 is provided with a non-magnetic substrate or a heat sink 70 on the side facing away from the planar transmission line structure 20.

[0066] In some embodiments, a non-magnetic substrate is typically disposed on the back side of the first magnetic thin film 30 and the second magnetic thin film 40. The non-magnetic substrate mainly provides a higher quality growth basis for the first magnetic thin film 30 and the second magnetic thin film 40. The non-magnetic substrate can be made of gadolinium gallium garnet (GGG) crystal material. When the signal line 21 is subjected to continuous injection of high-power microwave radio frequency signals such as radar interference, the overload signal is converted into a spin wave in the first magnetic thin film 30 and the second magnetic thin film 40 and dissipates a large amount of heat. Therefore, to solve the heat dissipation problem, this embodiment can remove the non-magnetic substrates of the first magnetic film 30 and the second magnetic film 40 through a grinding and polishing process. The exposed first magnetic film 30 and / or second magnetic film 40, having lost their non-magnetic substrates, are then directly fastened to the surface of a high thermal conductivity heat sink 70, such as a copper substrate or a molybdenum-copper alloy. This eliminates the use of garnet substrates with low thermal conductivity, thus preventing heat-induced frequency offset issues in the limiting device. It should be noted that, after the grinding and polishing process, the remaining film thickness of the first magnetic film 30 and the second magnetic film 40 in this embodiment is preferably 10 μm to 50 μm. If the thickness of the first magnetic film 30 and the second magnetic film 40 is 10 μm after grinding and polishing, the heat can be conducted to the heat sink 70 more quickly, ensuring the limiter withstands high-power continuous wave impacts. Without frequency drift, the heat sink 70 can be equipped with multiple heat sinks to increase the heat dissipation area. If the thickness of the first magnetic film 30 and the second magnetic film 40 is 25 μm, when the microwave radio frequency signal is transmitted in the signal line 21, the microwave magnetic field radiated to the upper and lower sides can cover the first magnetic film 30 and the second magnetic film 40 with the most efficient magnetic flux density. If the thickness of the first magnetic film 30 and the second magnetic film 40 is 50 μm, the effective magnetic volume of the first magnetic film 30 and the second magnetic film 40 can be maximized. When the antenna injects interfering microwave radio frequency signals, the first magnetic film 30 and the second magnetic film 40 can absorb more electromagnetic energy without falling into magnetic saturation, and convert the absorbed microwave radio frequency signals into spin waves and dissipate a large amount of heat.

[0067] like Figure 1 and Figure 2 As shown, in one embodiment of this application, when the planar transmission line structure 20 is a microstrip line, the signal line 21 is attached between the first magnetic thin film 30 and the second magnetic thin film 40; the metal layer 50 serves as a ground layer and is attached to the side of the first magnetic thin film 30 facing away from the signal line 21.

[0068] In some embodiments, if the planar transmission line structure 20 uses a microstrip line architecture, the signal line 21 is individually sandwiched between the first magnetic thin film 30 and the second magnetic thin film 40, while the metal layer 50 providing the reference return current and the signal line 21 are on different horizontal planes, such as... Figure 2 As shown, the metal layer 50 is attached to the lower surface of the second magnetic thin film 40, and the metal layer 50 can be deposited as a full-surface grounded copper plating. The second magnetic thin film 40 essentially acts as the microwave dielectric substrate of the microstrip line. The first magnetic thin film 30 is attached and pressed above the signal line 21, so that the microwave magnetic field originally diffused in the air above the microstrip line is fully absorbed and intercepted by the first magnetic thin film 30, thus optimizing the limiting depth of the limiter in the broadband range.

[0069] like Figure 1 and Figure 2 As shown, the signal line 21 further includes a first signal segment 22, a second signal segment 23, and a third signal segment 24. The first signal segment 22 extends inward from one side of the planar transmission line structure 20; the third signal segment 24 is parallel to the first signal segment 22 and extends inward from the other side of the planar transmission line structure 20; one or more second signal segments 23 are parallel to the first signal segment 22 and are located in the region between the first signal segment 22 and the third signal segment 24; wherein the first signal segment 22, one or more second signal segments 23, and the third signal segment 24 are spatially spaced apart and staggered to form an edge field coupling structure.

[0070] In some embodiments, for microstrip lines, this application may use coupled microstrip lines. Specifically, the first signal segment 22, several second signal segments 23, and the third signal segment 24 are no longer linearly connected, but are parallel to each other and staggered, presenting a geometric shape of sequentially spaced and interleaved arrangement, such as... Figure 2 As can be seen from the arrangement, the microwave radio frequency signal is electromagnetically coupled entirely between the first signal segment 22, several second signal segments 23, and the third signal segment 24 by the edge field of the gap. For example, after the microwave radio frequency signal is injected into the first signal segment 22, it is electromagnetically coupled with the second signal segment 23, so that the microwave radio frequency signal is transmitted to the second signal segment 23. When there are multiple second signal segments 23, the multiple second signal segments 23 are electromagnetically coupled sequentially, and finally the microwave radio frequency signal is transmitted to the third signal segment 24, and finally flows out from the third signal segment 24. In this embodiment, the first signal segment 22, several second signal segments 23, and the third signal segment 24 are arranged in an alternating manner. The edges of the first signal segment 22, several second signal segments 23, and the third signal segment 24 generate extremely strong local microwave magnetic fields. Under the action of the first magnetic thin film 30 and the second magnetic thin film 40, the microwave magnetic field can easily reach the critical point of spin wave excitation, realizing the interception of electromagnetic signals at the micro-power level.

[0071] The planar transmission line structure 20 of this embodiment can also be a stripline, which can adopt a conventional double-sided grounding method. That is, the signal line 21 is placed between the first magnetic film 30 and the second magnetic film 40, and the metal layer 50 is attached to the side of the first magnetic film 30 facing away from the signal line 21. The metal layer 50 is also attached to the side of the second magnetic film 40 facing away from the signal line 21. The metal layer 50 is used for grounding. When the microwave radio frequency signal is transmitted on the signal line 21, the microwave magnetic field on the upper and lower sides of the signal line 21 is confined between the first magnetic film 30 and the second magnetic film 40, and is also confined between the two metal layers 50. The microstrip line can also be a conventional ordinary microstrip line, such as a continuous, straight signal conductor. The limiting mainly relies on the microwave magnetic field generated by the signal line 21 itself to excite the first magnetic film 30 and the second magnetic film 40. This is only an extended embodiment of this application and will not be described in detail here.

[0072] This application also discloses a radio frequency device, which includes the frequency selective limiter described above.

[0073] Frequency selective limiters, as passive overload protection components, can be integrated into the printed circuit boards of radio frequency (RF) equipment. RF equipment equipped with limiters of this application, such as phased array radar receiver front-ends or satellite communication anti-interference channels, can limit large signal pulses in complex full-band strong electromagnetic interference environments, ensuring the safety of subsequent low-noise amplifiers and RF mixers.

[0074] 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 inventive 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 frequency-selective limiter, characterized in that, include: A planar transmission line structure, used to transmit microwave radio frequency signals and generate microwave magnetic fields; A first magnetic thin film covers the first surface of the planar transmission line structure; A second magnetic film covers the second surface of the planar transmission line structure, such that the planar transmission line structure is sandwiched between the first magnetic film and the second magnetic film. The microwave magnetic field generated by the planar transmission line structure is simultaneously coupled to the first magnetic thin film and the second magnetic thin film; The planar transmission line structure includes signal lines, and the signal lines include: The first signal segment extends inward from one side of the planar transmission line structure; The third signal segment extends inward from the other side of the planar transmission line structure; One or more second signal segments are located between the first signal segment and the third signal segment; The widths of the first signal segment and the third signal segment are both gradually changing, or the first signal segment, one or more second signal segments, and the third signal segment are arranged alternately and interleaved.

2. The frequency selective limiter as described in claim 1, characterized in that, The signal lines are arranged along the transmission direction of the microwave radio frequency signal; The signal line radiates a first magnetic field to the first surface of the planar transmission line structure and also radiates a second magnetic field to the second surface of the planar transmission line structure. The first magnetic field and the second magnetic field are coupled to the first magnetic thin film and the second magnetic thin film, respectively.

3. The frequency selective limiter as described in claim 1, characterized in that, The first magnetic thin film and the second magnetic thin film respectively contact the first and second surfaces of the planar transmission line structure to establish spin wave excitation regions on both the first and second surfaces of the planar transmission line structure.

4. The frequency selective limiter as described in claim 2, characterized in that, The planar transmission line structure also includes: A metal layer that cooperates with the signal line to guide the transmission of the microwave radio frequency signal; The planar transmission line structure formed by the signal line and the metal layer is selected from any one of coplanar waveguides, microstrip lines, or striplines.

5. The frequency selective limiter as described in claim 4, characterized in that, When the planar transmission line structure is a coplanar waveguide; The signal line extends from one side of the planar transmission line structure to the other side and is attached between the first magnetic film and the second magnetic film; The metal layer is located around the signal line and is attached between the first magnetic film and the second magnetic film.

6. The frequency-selective limiter as described in claim 1, characterized in that, A heat sink or a non-magnetic substrate is provided on the side of the first magnetic thin film away from the planar transmission line structure; And / or, the side of the second magnetic thin film away from the planar transmission line structure is provided with a non-magnetic substrate or heat sink.

7. The frequency selective limiter as described in claim 4, characterized in that, When the planar transmission line structure is a microstrip line; The signal line is attached between the first magnetic film and the second magnetic film; The metal layer is attached to the side of the first magnetic film facing away from the signal line.

8. A radio frequency device, characterized in that, The radio frequency device includes a frequency selective limiter as described in any one of claims 1 to 7.

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