Magnetic circuit structure of circulator, circulator, and electronic device
By employing a stacked magnet structure and a magnetic guide plate design in the ferrite circulator, the magnetic field distribution is optimized, solving the problem of uneven magnetization in the composite ferrite circulator and improving bandwidth and low-frequency performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SUZHOU HUABO ELECTRONIC TECH CO LTD
- Filing Date
- 2025-11-06
- Publication Date
- 2026-07-10
AI Technical Summary
Existing ferrite circulators suffer from magnetization inhomogeneity in their composite ferrite structures, leading to demagnetization and operating point shift, which in turn affects bandwidth and increases insertion loss.
A stacked magnet structure is adopted, and a closed magnetic circuit is formed by the first magnet and the second magnet. Different bias magnetic fields of different intensities are established on both sides of the ferrite layer. Combined with magnetic plates and pads, the magnetic field distribution is optimized to achieve a bias effect of strong inside and weak outside.
Without altering the basic structure of the circulator, the magnetization uniformity of the composite ferrite was improved, the demagnetization effect was reduced, and the low-frequency performance and bandwidth stability were enhanced.
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Figure CN121307459B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of circulator technology, and more particularly to a magnetic circuit structure for a circulator, a circulator, and an electronic device. Background Technology
[0002] With the continuous development of microwave communication and radar system technologies, higher demands are being placed on the performance of devices used in current systems. Ferrite circulators, as a typical non-reciprocal microwave device, rely on an external bias magnetic field to control the magnetization state of ferrite materials, achieving directional signal transmission and port isolation. However, when current ferrite circulators are biased using uniform permanent magnets, the magnetic field distribution is difficult to match with the ferrite structure, easily leading to demagnetization and bias unevenness, resulting in limited bandwidth and increased insertion loss. Therefore, improving the magnetization uniformity of composite ferrites in circulators is a crucial issue. Summary of the Invention
[0003] In view of this, embodiments of the present disclosure provide a magnetic circuit structure for a circulator, a circulator, and an electronic device, aiming to improve the magnetization uniformity of a composite ferrite circulator. In a first aspect, a magnetic circuit structure for a circulator is provided, comprising: a first magnet structure for generating a bias magnetic field passing through a ferrite layer of the circulator; the first magnet structure includes a first magnet and a second magnet stacked vertically, wherein the edge of the second magnet protrudes beyond the edge of the first magnet; and a second magnet structure disposed opposite to the first magnet structure for forming a closed magnetic circuit of the bias magnetic field; wherein, when the magnetic circuit structure is disposed in the circulator, the first magnet structure and the second magnet structure are respectively disposed on both sides of the ferrite layer, and a first bias magnetic field and a second bias magnetic field are respectively established in adjacent first and second ferrites on the ferrite layer, wherein the magnetic field strength of the first bias magnetic field is greater than the magnetic field strength of the second bias magnetic field; wherein the position of the first magnet corresponds to the position of the first ferrite, and the position of the second magnet corresponds to the position of the second ferrite.
[0004] The magnetic circuit structure of the above circulator can achieve a bias distribution that better meets the requirements of the composite structure within the ferrite layer by using the upper and lower opposing magnetic circuits in coordination with the geometric partitioning of the upper magnetic source, without changing or with minimal changes to the basic structure of the circulator. This reduces the demagnetization and operating point offset problems caused by uneven regional magnetization.
[0005] Optionally, the first magnet structure further includes: a magnetic guide plate disposed on the lower surface of the first magnet structure, used to concentrate and guide the magnetic flux of the bias magnetic field to provide a uniform bias magnetic field to the ferrite layer; wherein the size of the magnetic guide plate is determined based on the size of the ferrite layer.
[0006] Optionally, it also includes: a shim, disposed on the lower surface of the magnetic plate, for fixing the first magnet structure onto the ferrite layer and maintaining a preset distance.
[0007] Optionally, the vertical projection shapes of the first magnet and the second magnet include: regular and / or irregular shapes.
[0008] Optionally, the first magnet and the second magnet are arranged coaxially.
[0009] In a second aspect, a circulator is provided, comprising: a magnetic circuit structure of the circulator provided in the first aspect; a ferrite layer disposed between a first magnet structure and a second magnet structure, the ferrite layer comprising: a dielectric substrate and a nested ferrite structure disposed on the dielectric substrate, wherein the nested ferrite structure comprises a nested first ferrite and a second ferrite; a microstrip circuit disposed on the upper surface of the ferrite layer; and a ground layer disposed on the lower surface of the ferrite layer.
[0010] Optionally, the microstrip circuit includes: a center junction circuit and a matching circuit connected thereto; the center junction circuit is used to form power distribution and coupling of microwave signals between external ports connected to the circulator; the matching circuit is connected between the center junction and the external ports for impedance matching of the external ports.
[0011] Optionally, the first ferrite and the second ferrite are coaxially arranged; or, the first ferrite, the second ferrite, the first magnet, and the second magnet are coaxially arranged.
[0012] Optionally, the shape of the first ferrite matches the shape of the first magnet, and the shape of the second ferrite matches the shape of the second magnet.
[0013] Thirdly, an electronic device is provided, comprising the magnetic circuit structure of the circulator provided in the first aspect, or comprising the circulator provided in the second aspect. Attached Figure Description
[0014] The accompanying drawings used in the description of the embodiments of this disclosure are briefly introduced below:
[0015] Figure 1 The diagram shows a schematic diagram of the magnetic circuit structure of a circulator provided in some embodiments of this application;
[0016] Figure 2 The following are schematic diagrams illustrating the structure of a first magnet and a second magnet provided in some embodiments of this application;
[0017] Figure 3 The diagram shows a schematic representation of a circulator provided in some embodiments of this application;
[0018] Figure 4 This paper shows a top view of a ferrite layer provided in some embodiments of this application;
[0019] Figure 5 A comparison diagram of the internal magnetic field strength of two composite ferrites under a conventional magnetic circuit configuration and the magnetic circuit structure configuration of this application is provided.
[0020] Figure 6 A comparison diagram of the insertion loss of two composite ferrites under a conventional magnetic circuit configuration and the magnetic circuit structure configuration of this application is provided. Detailed Implementation
[0021] To more clearly illustrate the technical solutions in the embodiments of this disclosure, examples of implementation methods of this disclosure will be described below with reference to the accompanying drawings. The accompanying drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without creative effort. Adjustments and improvements made without departing from the concept of this disclosure are all within the protection scope of this disclosure.
[0022] To keep the drawings simple, each figure only schematically shows the parts relevant to the embodiment, and they do not represent the actual structure of the product. In addition, for the sake of clarity and ease of understanding, some figures only schematically show parts of components with the same structure or function, and there may actually be more or fewer components with the same structure or function.
[0023] In this disclosure, unless otherwise expressly specified and limited, ordinal numbers, such as “first,” “second,” etc., are used only to distinguish and describe related objects and should not be construed as indicating or implying the relative importance or order between related objects; furthermore, they do not represent the quantity of related objects. “Multiple” includes two or more, and other quantifiers are similar. “ / ” is used to describe the relationship between related objects, indicating an “or” relationship between them. “And / or” is used to describe the relationship between related objects, including any combination relationship between them, such as “a and / or b” including: “a alone,” “b alone,” or “a and b.” “One or more” or “at least one” of multiple objects refers to any object or any combination of multiple objects, such as “one or more of a1, a2, a3” or “at least one of a1, a2, a3” including: “a1 alone,” “a2 alone,” “a3 alone,” “a1 and a2,” “a1 and a3,” “a2 and a3,” or “a1, a2 and a3.”
[0024] Ferrite circulators are microwave devices that utilize the non-reciprocal effect generated by ferrite materials under an applied bias magnetic field. They are widely used in communication, radar, navigation, and radio frequency front-end systems. The basic structure of a ferrite circulator typically includes a ferrite substrate between upper and lower magnets, a central junction conductor, and external matching circuitry. By applying a bias magnetic field to the ferrite, directional signal transmission between different ports can be achieved. The wave impedance and coupling angle continuous tracking technique using a single ferrite has been proposed for designing broadband circulators, providing a design paradigm for external coupling and matching. However, the actual operating bandwidth of this circulator is less than 70% (upper sideband minus lower sideband divided by the center frequency), making ultra-wideband operation impossible. To improve the operating bandwidth and power capacity of circulators, a composite ferrite structure has been proposed in recent years. This involves combining ferrite materials with different saturation magnetizations on the same substrate, allowing the inner and outer regions to participate in signal propagation under different magnetization states. This structure can broaden the bandwidth and improve matching characteristics to a certain extent. However, in practical applications, the inner and outer regions of the composite ferrite respond differently to the bias magnetic field. The inner region requires a stronger magnetic field to reach saturation, while the outer region is fully magnetized under a weaker magnetic field. Existing permanent magnet bias structures often lead to over-biasing of the outer region and under-biasing of the inner region, resulting in an uneven magnetic field distribution within the substrate. This causes demagnetization and operating point shift, increasing losses in the low-frequency range and limiting the overall bandwidth. For example, this composite ferrite is composed of two or more ferrites with different ferromagnetic material parameters. The center is a cylindrical ferrite structure with the highest saturation magnetization, surrounded by one or more ring-shaped ferrites with decreasing saturation magnetization gradients. A ceramic dielectric substrate is then nested around the ring-shaped ferrites. When there is only one ring-shaped ferrite, the composite ferrite forms a double-nested composite ferrite; when there are two or more ring-shaped ferrites, the composite ferrite forms a triple-nested or multi-nested composite ferrite. Unlike single ferrites, the rotational modes within composite ferrites are reconstructed and adjusted, resulting in mode behavior favorable to positive toroidal motion over an ultra-wideband range. Furthermore, the electromagnetic field forms a perimeter mode at the interface between the composite ferrite cylinder and toroid, ensuring stable electromagnetic field transmission characteristics over a very wide frequency band. Because composite ferrites exhibit different saturation magnetization regions, corresponding to different static magnetic field responses, magnetic biasing becomes complex. Therefore, in practical design and applications, the static magnetic field analysis and configuration of composite ferrites require careful attention.
[0025] When performing electromagnetic simulations of composite ferrite circulators using commercial simulation software, the internal magnetic field value of the composite ferrite is typically set to a fixed value. However, the actual internal magnetic field distribution of a composite ferrite is not a uniform ideal value. This is because when the magnetic biasing component is combined with the circulator, even if the permanent magnet itself has a basically uniform magnetic bias, the magnetic bias applied to the composite ferrite is non-uniform due to the inherent demagnetization effect caused by the shape of the composite ferrite. Furthermore, if the uniformly applied bias magnetic field strength is adjusted just enough to saturate the disk ferrite, the toroidal ferrite with a lower saturation magnetization will have an internal magnetic field many times greater than that required for the ferrite disk to saturate, resulting in over-biasing. In short, non-uniform biasing and over-biasing of the composite ferrite will significantly reduce bandwidth performance and severely hinder the normal operation of the actual circulator. In view of this, this application provides a magnetic circuit structure for a circulator, a circulator, and an electronic device, which provides a bias magnetic field with a compact magnetic circuit structure and controllable magnetic field distribution. Under the premise of ensuring the overall size of the device, a strong inner and weak outer magnetization bias is formed in the composite ferrite substrate to reduce the demagnetization effect and improve the low-frequency performance and bandwidth stability of the circulator.
[0026] The following description is in conjunction with the accompanying drawings:
[0027] Figure 1 A schematic diagram of the magnetic circuit structure of a circulator provided in some embodiments of this application is shown. The magnetic circuit structure 100 includes: a first magnet structure 110 for generating a bias magnetic field passing through the ferrite layer of the circulator; the first magnet structure 110 includes a first magnet 111 and a second magnet 112 stacked vertically, wherein the edge of the second magnet 112 protrudes beyond the edge of the first magnet 111; and a second magnet structure 120, disposed opposite to the first magnet structure 110, for forming a closed magnetic circuit of the bias magnetic field; wherein, when the magnetic circuit structure 100 is disposed in the circulator, the first magnet structure 110 and the second magnet structure 120 are respectively disposed on both sides of the ferrite layer 210, and a first bias magnetic field and a second bias magnetic field are respectively established in the adjacent first ferrite 21 and second ferrite 22 on the ferrite layer 210, wherein the magnetic field strength of the first bias magnetic field is greater than the magnetic field strength of the second bias magnetic field; wherein, the position of the first magnet 111 corresponds to the position of the first ferrite 21, and the position of the second magnet 112 corresponds to the position of the second ferrite 22.
[0028] The above magnetic circuit structure can be used to establish a bias magnetic field within the ferrite layer 210, and to make the bias field strength in the region of the first ferrite 21 greater than that in the region of the second ferrite 22, so as to meet the field strength requirements of different regions on the ferrite layer. The first magnet structure 110 is used to generate an axial bias magnetic field passing through the ferrite layer 210, and to achieve a radially differentiated distribution of the magnetic field through internal geometric partitioning. The first magnet structure 110 may include a first magnet 111 and a second magnet 112 stacked vertically, both of which can be permanent magnets, such as permanent magnets made of materials including but not limited to neodymium iron boron, samarium cobalt, etc., and metallic materials with high magnetic permeability. The position of the first magnet 111 can correspond to the region where the first ferrite 21 is located in the ferrite layer 210, and the edge of the second magnet 112 protrudes outward relative to the edge of the first magnet 111, and its position corresponds to the region where the second ferrite 22 is located in the ferrite layer 210. When the edge of the second magnet 112 protrudes beyond the edge of the first magnet 111, the protrusion can be complete, meaning that when the first magnet 111 and the second magnet 112 are coaxially arranged, the edge of the second magnet 112 can completely cover the edge of the first magnet 111 in vertical projection; or it can be partial, meaning that when coaxially arranged, a portion of the edge of the second magnet 112 covers a portion of the edge of the first magnet 111. The magnetization directions of the first magnet 111 and the second magnet 112 can be aligned with the direction toward the ferrite layer 210, serving as the magnetic source of the ferrite layer 210. Due to the radial extension of the second magnet 112, the first magnet structure 110 can exhibit excitation characteristics in both inner and outer regions within the ferrite layer 210. In the ferrite layer 210, the first ferrite 21 near the center is primarily affected by the magnetic flux contributed by the first magnet 111, forming a first bias magnetic field. The second ferrite 22 near the outer edge is primarily affected by the magnetic flux contributed by the second magnet 112, forming a second bias magnetic field. This provides matched field strength levels for different regions of the composite ferrite. The second magnet structure 120 is positioned opposite the first magnet structure 110 on the other side of the ferrite layer 210, used to close the magnetic circuit of the bias magnetic field, increasing the effective axial component and reducing magnetic flux leakage. The second magnet structure 120 can be a mirror image of the first magnet structure 110, or it can be a thin metal plate with high permeability to constrict magnetic lines of force. To reduce the cross-sectional height of the magnetic assembly, the first magnet structure can be a thin metal plate with permeability that meets the current circulator design requirements. By providing a second magnet structure 120 below the ferrite layer 210, the magnetic field lines injected into the ferrite layer 210 from the first magnet structure 110 can form a substantially closed magnetic flux path inside the device, thereby strengthening the axial bias magnetic field passing through the ferrite layer 210 and improving magnetic flux utilization and bias stability without significantly increasing the device's external dimensions. The ferrite layer 210 is a functional dielectric layer that withstands the bias magnetic field, and it has adjacent first ferrites 21 and second ferrites 22 arranged radially.By combining materials and geometry, different regions exhibit different operating point requirements under bias. The magnetic circuit structure 100 establishes a first bias magnetic field and a second bias magnetic field within the ferrite layer 210. This regionalized biasing within the same substrate helps the composite ferrite achieve a more suitable magnetization state within the target frequency band, providing a stable foundation for the circulator to achieve non-reciprocal transmission. When this magnetic circuit structure 100 is applied to a circulator, before the circulator is powered on, the magnetic circuit structure 100 has already established a bias magnetic field within the ferrite layer 210 under the action of the first magnet structure 110. Due to the geometric partitioning within the first magnet structure 110 (i.e., the edge relationship between the first magnet 111 and the second magnet 112), the ferrite layer 210 exhibits a radial field strength variation, allowing the composite ferrite to operate in a more suitable magnetization state in different regions, thereby reducing magnetization inhomogeneity and operating point drift caused by regional mismatch. The magnetic circuit structure provided in this application can achieve a bias distribution that better meets the requirements of the composite structure within the ferrite layer 210 through the synergy of the upper and lower opposing magnetic circuits and the geometric partitioning of the upper magnetic source, without changing or with minimal changes to the basic structure of the circulator. This reduces the demagnetization and operating point offset problems caused by uneven regional magnetization.
[0029] Continue to refer to Figure 1 The first magnet structure 110 further includes a magnetic guide plate 113 disposed on the lower surface of the second magnet 112, used to concentrate and guide the magnetic flux of the bias magnetic field to provide a uniform bias magnetic field to the ferrite layer 210; wherein the size of the magnetic guide plate is determined based on the size of the ferrite layer.
[0030] In the above embodiments, the magnetic guide plate 113 can be made of a high permeability material to ensure effective guidance of magnetic flux. The size (e.g., outer diameter) of the magnetic guide plate 113 can be determined according to the planar dimensions of the ferrite layer 210, so that it covers the effective area of the ferrite layer 210. By adding the magnetic guide plate 113 below the first magnet structure 110, the magnetic lines of force from the second magnet 112 are converged and guided, so that the magnetic flux density passes through the ferrite layer 210 more concentratedly, thereby reducing the leakage of magnetic flux in the air and improving the effective utilization rate of the bias magnetic field. Since the magnetic guide plate 113 has high permeability, its redistribution of magnetic lines of force can make the magnetic field on the surface of the ferrite layer 210 smoother and more uniform, reduce the magnetic flux density gradient between different regions, and improve the consistency of the bias magnetic field in the radial direction. Compared with simply thickening the permanent magnet to increase the field strength, using the magnetic guide plate 113 can improve the magnetic flux distribution while keeping the overall thickness unchanged.
[0031] Continue to refer to Figure 1It also includes a spacer 130, disposed on the lower surface of the magnetic conductive plate 113, used to fix the first magnet structure 110 onto the ferrite layer 210 and maintain a preset distance. The spacer 1130 may be made of a non-magnetic material and is arranged between the magnetic circuit structure 100 and the circuit structure (such as the central junction circuit) of the circulator to support the magnetic circuit structure 100. The spacer 130 may be fixed by adhesive.
[0032] In some embodiments of this application, the vertical projection shapes of the first magnet 111 and the second magnet 112 include: regular shapes and / or irregular shapes.
[0033] The vertical projection shapes of the first magnet 111 and the second magnet 112 can be the same or different. When the shapes are the same, for example, both the vertical projection shapes of the first magnet 111 and the second magnet 112 can be regular shapes, such as polygons (e.g., triangles, rectangles, etc.), arc shapes (e.g., circles, etc.), or irregular shapes, and the edge of the vertical projection shape of the first magnet 111 protrudes beyond the edge of the vertical projection shape of the second magnet 112. When the shapes are different, for example, the former of the first magnet 111 is a regular shape and the latter is an irregular shape, or vice versa. The specific shapes can be set according to the design of the technician. For example, Figure 2 The diagram illustrates the structure of a first magnet and a second magnet according to some embodiments of this application. The first magnet 111 and the second magnet 112 can be coaxially arranged. For example, the vertical projection shapes of the first magnet 111 and the second magnet 112 are identical, both being circular, and they are coaxial; that is, the first center point O1 on the vertical projection plane of the first magnet 111 and the second center point O2 on the vertical projection plane of the second magnet 112 can be collinear through an axis L perpendicular to the vertical projection plane. Furthermore, the first radius r1 of the first magnet 111 is smaller than the second radius r2 of the second magnet 112. Further, other structures of the magnetic circuit structure 100, such as the second magnet structure 120, the magnetic guide plate 113, and the gasket 130, can all be distributed with the axis L as the central axis.
[0034] Figure 3 A schematic diagram of a circulator provided in some embodiments of this application is shown. The circulator includes: a magnetic circuit structure 100 of the circulator provided in the above embodiments; a ferrite layer 210 disposed between a first magnet structure 110 and a second magnet structure 120, the ferrite layer 210 including: a dielectric substrate 212 and a nested ferrite structure 211, the nested ferrite structure 211 being disposed on the dielectric substrate 212, wherein the nested ferrite structure 211 includes a nested first ferrite 21 and a second ferrite 22; a microstrip circuit 230 disposed on the upper surface of the ferrite layer 220; and a ground layer 240 disposed on the lower surface of the ferrite layer.
[0035] In the above embodiments of the circulator, the nested ferrite structure 211 can be formed by nesting a first ferrite 21 and a second ferrite 22, for example, by setting them coaxially, where the first ferrite 21 is located in the central region and has a cylindrical structure; the second ferrite 22 surrounds the outside of the first ferrite 21 and has a ring structure. They can also be non-coaxial, meaning the axes of the first ferrite 21 and the second ferrite 22 are not on the same straight line and have a certain deviation. The first ferrite 21 and the second ferrite 22 have different material properties; the first ferrite 21 has a higher saturation magnetization, while the second ferrite 22 has a lower saturation magnetization. Through this composite layout, combined with the effects of the first magnet 111 and the second magnet 112, a magnetic characteristic distribution with a higher inner area and a lower outer area can be formed, making the magnetization of the nested ferrite structure 211 more uniform and effectively reducing the common problems of excessive bias in the outer region or under-bias in the inner region in traditional circulators. The dielectric substrate 212 can be made of a ceramic or composite dielectric material with an appropriate dielectric constant to support the ferrite structure and form an electromagnetic coupling structure with the microstrip circuit 230 above it. The dielectric substrate 212 can simultaneously provide mechanical strength and insulation performance for the circulator, ensuring the overall stability of the device. The ground layer 240 can be made of a highly conductive metallic material (such as copper or silver) and serves as a reference ground for the microstrip circuit. It not only forms the return path of the microstrip transmission line but also provides stable electromagnetic boundary conditions, which helps to improve signal transmission characteristics and port isolation performance. The ground layer 240 can also provide structural support for the circulator, making the assembly of the ferrite layer 210 and the second magnet structure 120 more stable. When the circulator is operating, the bias magnetic field established by the magnetic circuit structure 100 passes through the ferrite layer 210 axially. Due to the different material parameters of the inner and outer regions of the nested ferrite structure 211, and the fact that the bias magnetic field is stronger inside and weaker outside, the magnetization state inside the ferrite layer 210 is optimized, and the non-reciprocal characteristics are enhanced. At this point, the electromagnetic field coupling between different ports in the microstrip circuit 230 is affected by the magnetization direction of the ferrite layer 210, thereby achieving directional signal transmission (for example, when there are 3 ports connected, transmission from port 1 to port 2 and isolation of port 3 are achieved). The second magnet structure 120 provides a closed magnetic circuit, making the bias magnetic field distribution more stable, while the ground layer 240 ensures uniform return of the microwave electric field, improving the overall electromagnetic consistency of the device.
[0036] Continue to refer to Figure 3The microstrip circuit 230 includes a center junction circuit and a matching circuit connected thereto. The center junction circuit is used to achieve power distribution and coupling of microwave signals between external ports connected to the circulator. The matching circuit is connected between the center junction and the external ports for impedance matching of the external ports. The microstrip circuit 230 can be disposed on the upper surface of the ferrite layer 210, and includes the center junction circuit and matching circuits connected to multiple ports. The center junction circuit can adopt a Y-shaped, triangular, or disk-shaped structure to achieve power distribution and coupling of microwave signals between different ports. The matching circuit is used to achieve impedance matching with external circuits, reduce reflections, and improve transmission efficiency. The matching circuit can be composed of multiple transmission lines with variable impedance, or it can be directly connected to a transmission line with a preset resistance value (e.g., 50 ohms).
[0037] Figure 4 A top view of a ferrite layer provided in some embodiments of this application is shown. (Refer to reference...) Figure 1 , Figure 3 The first ferrite 21 and the second ferrite 22 can be coaxially arranged. In this case, the first ferrite 21, the second ferrite 22, and the first magnet 111, the second magnet 112 may not be completely coaxial, but rather have a certain axial deviation between each pair. Alternatively, the first ferrite 21, the second ferrite 22, the first magnet 111, and the second magnet 112 can be coaxially arranged. In some embodiments, in the vertical projection direction, the first ferrite 21 and the first magnet 111 have the same shape, and the second ferrite 22 and the second magnet 112 have the same shape.
[0038] Continue to refer to Figure 1 The shape of the first ferrite 21 matches the shape of the first magnet 111, and the shape of the second ferrite 22 matches the shape of the second magnet 112. Shape matching can mean that they are identical in shape and size, or identical in shape but with some difference in size. Regarding the size difference, the size difference between the first ferrite 21 and the first magnet 111 is sufficient to ensure that the magnetic field formed by the first magnet 111 covers the area of the first ferrite 21. The second ferrite 22 and the second magnet 112 have the same design, and will not be specifically limited here.
[0039] In some embodiments of this application, a scheme for the size and shape of various structures in a composite ferrite circulator is provided. The first magnet structure includes a first disc-shaped permanent magnet component (i.e., the first magnet mentioned above), a second disc-shaped permanent magnet component (i.e., the second magnet mentioned above) with a radius larger than that of the first disc-shaped permanent magnet component, and a magnetically conductive plate made of a thin iron plate with a permeability higher than 3000. The radius of the first disc-shaped permanent magnet component can be 1-2 mm, and the height can be 0.5-1.2 mm. The magnetic material parameters used are a remanence Br between 0.8-1.2 T and a magnetic coercivity between 585 kA / m and 885 kA / m. The radius of the second disc-shaped permanent magnet component 12 is 0.8-1.5 mm larger than that of the first disc-shaped permanent magnet component, and the height of the second disc-shaped permanent magnet component 12 is 0.5-1.2 mm. The magnetic material parameters used are a remanence Br between 0.8-1.2 T and a magnetic coercivity between 585 kA / m and 885 kA / m. The permeability is between kA / m; the radius of the magnetically conductive plate 13, made of thin iron sheet, is 1-3 mm, the height is 0.2-0.5 mm, and the permeability is between 3000-5000. The radius of the shims fixing the first and second magnets is 1.5-3 mm, and the thickness is 0.5-1 mm. The center junction circuit and matching circuit of the composite ferrite circulator adopt a Y-shaped center junction. In order to match with the 50-ohm transmission line, a matching circuit is constructed using more than three quarter-wavelength impedance transformers. The thickness of the nested composite structure substrate (i.e., the ferrite layer mentioned above) is between 0.3 and 0.8 mm. The material parameters of the inner cylindrical ferrite with high saturation magnetization (i.e., the first ferrite mentioned above) are a saturation magnetization of 2400-3000 Gauss, a dielectric constant of approximately 15, and a radius of 1-1.7 mm. The material parameters of the outer ring-shaped ferrite with lower saturation magnetization (i.e., the second ferrite mentioned above) are a saturation magnetization of 1500-1800 Gauss, a dielectric constant of approximately 15, an outer diameter of 2.2-2.6 mm, and an inner diameter consistent with the radius of the cylindrical ferrite. The dielectric constant of the ceramic substrate (the dielectric substrate mentioned above) is between 13 and 25, and the cross-sectional dimensions are within 12 mm × 12 mm. The cross-sectional dimensions of the grounding metal layer (i.e., the grounding layer mentioned above) are consistent with the dimensions of the ceramic substrate. The lower magnet structure (i.e., the second magnet structure mentioned above) uses an iron sheet with a cross-sectional size of no more than 12mm × 12mm and a thickness of 0.5-1mm to achieve a longitudinal closed magnetic circuit. Taking this structure as an example, its internal magnetic field strength is compared with that of a conventional magnetic circuit configuration.
[0040] Figure 5A comparison diagram of the internal magnetic field strength of two composite ferrites under a conventional magnetic circuit configuration and the magnetic circuit structure configuration of this application is provided. By introducing a stacked irregular magnetic circuit configuration, the magnetic field strength value inside the composite ferrite is reduced, and a uniform magnetic field distribution is maintained in the magnetic components with different saturation magnetization values. This allows the composite ferrite circulator to operate under ideal low-field conditions, thereby improving the operating bandwidth.
[0041] Figure 6 A comparison graph of insertion loss for two composite ferrite circulators with different magnetic circuit configurations (one using a standard magnetic circuit and the other using the magnetic circuit structure described in this application) is provided. The horizontal axis represents frequency, and the vertical axis represents decibels. Compared to the composite ferrite circulator with a standard magnetic circuit configuration, the circulator using the stacked irregular magnetic circuit exhibits better performance at the lower sidebands, with a significant reduction in insertion loss, resulting in an insertion loss bandwidth of over 120% for the composite ferrite circulator.
[0042] Based on the same technical concept, this application also provides an electronic device, including the magnetic circuit structure of the circulator provided in the above embodiments, or including the circulator provided in the above embodiments.
[0043] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not described in detail or in a particular embodiment can be referred to in the relevant descriptions of other embodiments. Furthermore, the above embodiments can be freely combined as needed.
Claims
1. A magnetic circuit structure for a circulator, characterized in that, include: A first magnet structure is used to generate a bias magnetic field through the ferrite layer of the circulator. The first magnet structure includes a first magnet and a second magnet stacked one on top of the other, wherein the edge of the second magnet protrudes beyond the edge of the first magnet. The second magnet structure is disposed opposite to the first magnet structure and is used to form a closed magnetic circuit for the bias magnetic field; When the magnetic circuit structure is disposed in the circulator, the first magnet structure and the second magnet structure are respectively disposed on both sides of the ferrite layer, and a first bias magnetic field and a second bias magnetic field are respectively established in the adjacent first ferrite and second ferrite on the ferrite layer, wherein the magnetic field strength of the first bias magnetic field is greater than the magnetic field strength of the second bias magnetic field. The position of the first magnet corresponds to the position of the first ferrite, and the position of the second magnet corresponds to the position of the second ferrite.
2. The magnetic circuit structure of the circulator according to claim 1, characterized in that, The first magnet structure further includes: A magnetic guide plate is disposed on the lower surface of the first magnet structure to concentrate and guide the magnetic flux of the bias magnetic field so as to provide a uniform bias magnetic field to the ferrite layer. The dimensions of the magnetic conductive plate are determined based on the dimensions of the ferrite layer.
3. The magnetic circuit structure of the circulator according to claim 2, characterized in that, Also includes: A gasket is disposed on the lower surface of the magnetic plate to fix the first magnet structure onto the ferrite layer and maintain a preset distance.
4. The magnetic circuit structure of the circulator according to any one of claims 1 to 3, characterized in that, The vertical projection shapes of the first magnet and the second magnet include: regular shapes and / or irregular shapes.
5. The magnetic circuit structure of the circulator according to claim 4, characterized in that, The first magnet and the second magnet are coaxially arranged.
6. A circulator, characterized in that, include: The magnetic circuit structure of the circulator according to any one of claims 1 to 5; A ferrite layer is disposed between the first magnet structure and the second magnet structure. The ferrite layer includes a dielectric substrate and a nested ferrite structure. The nested ferrite structure is disposed on the dielectric substrate, wherein the nested ferrite structure includes a first ferrite and a second ferrite nested together. A microstrip circuit is disposed on the upper surface of the ferrite layer; A grounding layer is disposed on the lower surface of the ferrite layer.
7. The circulator according to claim 6, characterized in that, The microstrip circuit includes: a central junction circuit and a matching circuit connected thereto; A central junction circuit is used to form power distribution and coupling of microwave signals between external ports connected to the circulator; A matching circuit, connected between the central junction circuit and the external port, is used to perform impedance matching on the external port.
8. The circulator according to claim 7, characterized in that, The first ferrite and the second ferrite are coaxially arranged; or, The first ferrite, the second ferrite, the first magnet, and the second magnet are coaxially arranged.
9. The circulator according to claim 8, characterized in that, The shape of the first ferrite matches the shape of the first magnet, and the shape of the second ferrite matches the shape of the second magnet.
10. An electronic device, characterized in that, It includes the magnetic circuit structure of the circulator as described in any one of claims 1 to 5, or includes the circulator as described in any one of claims 6 to 9.