A nested ferrite switch based on a composite magnetic circuit

Abstract

This invention discloses a nested ferrite switch based on a composite magnetic circuit, belonging to the field of microwave device technology. It includes a central ferrite rod (1), an insulating dielectric sleeve (2), an excitation coil (3), and a dielectric substrate (5). A coplanar waveguide transmission line (6) is provided on the dielectric substrate (5). The central ferrite rod (1) is embedded in the central junction of the coplanar waveguide. A soft magnetic metal yoke (4) with a magnetic flux density of 2 to 5 times the saturation magnetization of the ferrite is provided outside the central ferrite rod (1). This invention uses a coplanar waveguide and a special magnetic yoke design for the ferrite switch, which can achieve the advantages of high power capacity and wide bandwidth. Through simulation design, the relative bandwidth of the ferrite switch designed with this structure can reach more than 15%.

Description

Technical Field

[0001] This invention relates to the field of microwave device technology, and in particular to a nested ferrite switch based on a composite magnetic circuit. Background Technology

[0002] Currently, microwave systems are increasingly developing towards broadband and high power, especially in microwave receiver systems and multi-channel switching systems, which places higher demands on the application of broadband, high power, and miniaturized ferrite switches.

[0003] The existing switches are mainly implemented using the following methods:

[0004] 1. Waveguide ferrite switch

[0005] The waveguide ferrite switch mainly consists of: a central irregularly shaped ferrite core (a), an excitation coil (b), a waveguide cavity wall (c), a dielectric gasket (d), and a rectangular waveguide (e). Its main structure is as follows: Figure 1 As shown.

[0006] This type of switch achieves fast switching by using different excitation current directions in the excitation coil b to control the magnetization direction of the internal ferrite. These switches typically use waveguides as the transmission path, resulting in a relatively large size; the dimensions without the excitation coil are approximately 30mm × 30mm × 21mm.

[0007] Furthermore, the existing waveguide ferrite switches have an operating bandwidth of around 10%-20%, which cannot meet the system's broadband requirements. However, drilling holes in the ferrite results in a lower ferrite size at higher frequencies, leading to a lower yield rate. In engineering applications, the ferrite may crack, resulting in lower reliability. Additionally, as a waveguide structure, its large size makes it unsuitable for high-integration requirements.

[0008] 2. Waveguide mechanical switch

[0009] The waveguide mechanical switch mainly includes: electrical interface f, drive motor g, bearing h, internal rotor i, cavity j, motor cover k, etc., and its main structure is as follows: Figure 2 As shown;

[0010] This type of switch primarily uses a single-pole double-throw control motor to rotate, which in turn rotates the bearing to drive the internal rotor of the switch, thus switching the microwave channels. These switches typically use waveguides as the transmission path, resulting in a relatively large size, approximately 40mm × 40mm × 80mm.

[0011] Existing waveguide mechanical switches can achieve full bandwidth operation in rectangular waveguides and have a large power capacity. However, since these switches are usually driven by motors, the switching time is typically on the order of milliseconds, which may result in a long time dead zone during full-duplex transmission and reception. In addition, these switches are mostly mechanical structures, and improper assembly tolerance control may cause jamming during subsequent operation, resulting in the switch failing to function properly.

[0012] In other words, while existing waveguide ferrite switches offer high power, reaching up to 100W in the Ka band, they are bulky, have low reliability, and are difficult to integrate. Waveguide mechanical switches, on the other hand, while offering large power capacity and wide bandwidth, typically have switching speeds in the millisecond range, potentially causing prolonged system blind spots and reducing the operational performance of the system. They also suffer from large size. Therefore, both ferrite and waveguide mechanical switches have technical drawbacks in engineering applications. Summary of the Invention

[0013] The purpose of this invention is to provide a nested ferrite switch based on a composite magnetic circuit to solve the above-mentioned problems.

[0014] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a nested ferrite switch based on a composite magnetic circuit includes a central ferrite rod, an insulating dielectric sleeve, an excitation coil, and a dielectric substrate. A coplanar waveguide transmission line is disposed on the dielectric substrate. The central ferrite rod is embedded in the central junction of the coplanar waveguide. A soft magnetic metal yoke with a magnetic flux density of 2 to 5 times the saturation magnetization of the ferrite is disposed outside the central ferrite rod. The excitation coil is wound on the soft metal yoke post. The soft metal yoke is embedded together with the dielectric substrate.

[0015] This invention is based on a micro-nano process platform known to those skilled in the art. It embeds a central ferrite rod and uses a novel soft magnetic metal composite magnetic circuit on the outside. This allows for simple and effective magnetization of the central ferrite rod in the magnetic circuit. By changing the direction of the current in the excitation coil, the direction of the magnetic field in the composite magnetic circuit can be quickly changed, enabling high-power, wideband, and miniaturized applications of the switch.

[0016] Specifically, this invention utilizes a micro-nano process platform, using silicon as the substrate as the medium, and designs a coplanar waveguide on the silicon substrate as the transmission path for microwave signals. Simultaneously, a ferrite rod is embedded in the central junction of the coplanar waveguide. A soft magnetic metal with a magnetic flux density of 2-5 times the ferrite saturation magnetization intensity and good machinability and toughness is used as the yoke of this product. Preferably, the yoke is metallized (e.g., gold-plated to facilitate welding with the dielectric substrate or central ferrite substrate, achieving a tight connection and facilitating the magnetization of the central ferrite rod). The yoke forms a closed loop on its periphery. The saturation magnetization of the ferrite is controlled by an excitation coil (also called an excitation coil), realizing the device's loop function. During application, changing the current direction of the excitation coil changes the direction of the magnetic lines of force in the yoke, realizing the device's switching function (loop function in different directions).

[0017] This invention employs a soft magnetic metal material with a special magnetic flux density as the magnetic yoke. The saturation magnetization of the soft magnetic metal itself is higher than that of ferrite, being 2-5 times that of ferrite. When forming a magnetic circuit, the cross-section of the soft magnetic metal yoke can be reduced to 1 / 2-1 / 5 of its original size. It is particularly important to emphasize that the soft magnetic metal is easy to process and is not as easily broken as ferrite. There are many methods for forming a closed magnetic circuit with the ferrite in the working area, and it is not easily detached. A closed magnetic circuit can be achieved through methods other than bonding.

[0018] Based on the requirement of magnetic flux continuity, the magnetic flux corresponding to the vertical profile of the ferrite flux in the working region should be the same as that corresponding to the vertical profile of the soft magnetic flux. This is because the saturation magnetization of the soft magnetic material is greater than that of the ferrite. When the ferrite is saturated, the soft magnetic material is only partially magnetized. Furthermore, the coercivity of the soft magnetic material is close to that of the ferrite. Therefore, the remanence corresponding to each excitation state of the ferrite in the working region can be maximized without requiring a large-sized soft magnetic yoke. A difference of several times in saturation magnetization means that the cross-sectional area of ​​the soft magnetic yoke is inversely reduced. Of course, in practical applications, magnetic locking compensation can also be achieved by appropriately adjusting the cross-section of the magnetic circuit.

[0019] As a preferred technical solution: the soft magnetic metal yoke includes an upper yoke and a lower yoke, which are combined with the central ferrite rod by welding.

[0020] It should be noted that the magnetic yoke needs to be separate. It can be mirror-joined or not, and then joined together by screws or other means to form a complete magnetic circuit.

[0021] On the one hand, it can improve the grounding effect of ferrite, and on the other hand, it helps ferrite dissipate heat.

[0022] As a preferred technical solution, the soft magnetic metal is industrial pure iron or an iron-nickel-cobalt alloy.

[0023] Compared with existing technologies, the advantages of this invention are as follows: This invention employs a coplanar waveguide and a special magnetic yoke design for the ferrite switch, achieving high power capacity and wide bandwidth. Through simulation design, the relative bandwidth of the ferrite switch designed with this structure can reach more than 15%. This invention can effectively improve the wideband high-power design of microwave ferrite switches, enhance the combat performance of the system, and can be effectively integrated into the antenna end of the microwave system, reducing the system size by more than 10%. In addition, the ferrite switch of this invention has a switching time in the microsecond range, which can avoid the problem of long-term blind spots in radar systems. Moreover, it is small in size, high in power, easy to integrate, and contributes to the development of national defense and military industries. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a ferrite switch in the prior art;

[0025] Figure 2 This is a schematic diagram of a waveguide mechanical switch structure in the prior art;

[0026] Figure 3 This is a schematic diagram of the ferrite switch according to Embodiment 1 of the present invention;

[0027] Figure 4 for Figure 3 AA section view;

[0028] Figure 5 This is a reverse loss diagram of the ferrite switch in Embodiment 1 of the present invention;

[0029] Figure 6 This is a standing wave diagram of the ferrite switch in Embodiment 1 of the present invention.

[0030] In the diagram: a, ferrite; b, excitation coil; c, waveguide cavity wall; d, dielectric gasket; e, rectangular waveguide; f, electrical interface; g, drive motor; h, bearing; i, internal rotor; j, cavity; k, motor cover;

[0031] 1. Central ferrite rod; 2. Insulating dielectric sleeve; 3. Excitation coil; 4. Soft magnetic metal yoke; 5. Dielectric substrate; 6. Coplanar waveguide transmission line. Detailed Implementation

[0032] The invention will now be further described with reference to the accompanying drawings.

[0033] Example 1:

[0034] A nested ferrite switch based on a composite magnetic circuit, see [link / reference]. Figure 3 and Figure 4The device includes a central ferrite rod 1, an insulating dielectric sleeve 2, an excitation coil 3, and a dielectric substrate 5. In this embodiment, the dielectric substrate 5 is a silicon-based substrate. A coplanar waveguide transmission line 6 is disposed on the dielectric substrate 5. The central ferrite rod 1 is embedded in the central junction of the coplanar waveguide. A soft magnetic metal yoke 4 with a magnetic flux density three times the saturation magnetization of the ferrite is disposed outside the central ferrite rod 1. In this embodiment, the soft magnetic metal yoke 4 is a yoke made of industrial pure iron. The soft magnetic metal yoke 4 includes an upper yoke and a lower yoke, which are mirror-bonded to the central ferrite rod 1 by welding.

[0035] The switch simulation diagram of this embodiment is as follows: Figure 5 As shown, from Figure 5 It can be seen that the return loss is ≤-20dB within the operating frequency band of 26.5-40GHz (relative bandwidth 10%-20%), which fully meets the design requirements of the project.

[0036] Meanwhile, the power capacity of this type of ferrite switch in the ka band is basically the same as that of the SIW circulator, reaching up to 80W continuous waveguide, and its power capacity is perfectly matched with that of the waveguide ferrite switch.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A nested ferrite switch based on a composite magnetic circuit, characterized in that: The device includes a central ferrite rod (1), an insulating dielectric sleeve (2), an excitation coil (3), and a dielectric substrate (5). A coplanar waveguide transmission line (6) is provided on the dielectric substrate (5). The central ferrite rod (1) is embedded in the central junction of the coplanar waveguide. A soft magnetic metal yoke (4) with a magnetic flux density of 2 to 5 times the saturation magnetization of the ferrite is provided outside the central ferrite rod (1). The excitation coil (3) is wound on the column of the soft magnetic metal yoke (4). The soft magnetic metal yoke (4) is embedded together with the dielectric substrate (5). The soft magnetic metal yoke (4) includes an upper yoke and a lower yoke, which are provided separately.

2. The nested ferrite switch based on a composite magnetic circuit according to claim 1, characterized in that: The upper and lower magnetic yokes are joined to the central ferrite rod (1) by welding.

3. A nested ferrite switch based on a composite magnetic circuit according to claim 1, characterized in that: The soft magnetic metal is industrial pure iron or an iron-nickel-cobalt alloy.

4. A nested ferrite switch based on a composite magnetic circuit according to claim 1, characterized in that: The dielectric substrate (5) is a silicon-based substrate or a ceramic dielectric substrate.

5. A nested ferrite switch based on a composite magnetic circuit according to claim 1, characterized in that: The soft magnetic metal yoke (4) is embedded together with the dielectric substrate (5) by welding or screw connection.

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