An integrated thin film noise suppressor

Abstract

The present application belongs to the field of magnetic functional materials and components, and relates to high-frequency electromagnetic interference suppression technology, in particular to an integrated thin film noise suppressor. The present application divides the magnetic thin film into layers, integrates multiple layers of soft magnetic thin film on the transmission line through the isolation of the insulating layer, realizes the suppression of noise through the magnetic loss of the soft magnetic thin film, and can form an integrated thin film noise suppressor with single frequency point or multiple frequency points in the frequency range of 0-6GHz. The present application provides an optional scheme for further satisfying wideband electromagnetic noise suppression by adjusting the type or thickness of the magnetic film material according to actual needs. The present application has the advantages of simple structure and process, integrability, high performance, wide frequency band and high applicability.

Description

Technical Field

[0001] This invention belongs to the field of magnetic functional materials and components, and relates to high-frequency electromagnetic interference suppression technology, specifically an integrated thin-film noise suppressor. Background Technology

[0002] In recent years, with the miniaturization and weight reduction of electronic and communication equipment, the installation density of electronic circuit components has increased. The electromagnetic noise radiated by electronic components causes problems such as electromagnetic interference and magnetic field coupling between electronic components or between electronic circuits, leading to malfunctions of electronic and communication equipment.

[0003] To prevent this problem, near-field thin-film noise suppressors are installed on the equipment accessories to prevent electromagnetic interference and unwanted electromagnetic coupling. The attenuation mechanism of these thin-film noise suppressors is mainly due to the ferromagnetic resonance loss, eddy current loss, and LC resonance loss of the multilayer device structure in the magnetic thin film.

[0004] Commonly used electromagnetic thin-film noise suppressors are on the millimeter scale, such as the noise suppression sheet disclosed in patent application number CN202011319586.X. These are typically placed as surface-mount components near electronic circuits. Such noise suppressors offer high shape flexibility and are widely used in electronic and communication equipment to combat noise. Non-integrated thin-film noise suppressors exhibit poor noise suppression performance when thin. To ensure their performance, a certain thickness is required. Therefore, with the increasing integration of electronic devices, the relatively large size of these non-integrated noise suppressors significantly limits their application in miniaturized and integrated electronic devices.

[0005] For thin-film noise suppressors, with the same magnetic film thickness, integrated thin-film noise suppressors show a significant improvement in power loss compared to non-integrated ones. Existing integrated thin-film noise suppressors are typically fabricated by combining coplanar waveguides or microstrip lines with a single-layer magnetic film. While these are small in size, their noise suppression bandwidth is narrow, making them unsuitable for complex high-frequency electromagnetic environments. Existing multilayer noise suppressors utilize [ferromagnetic layers / antiferromagnetic layers]. n Switched-coupled multilayer films broaden the bandwidth by utilizing the spin-transfer effect of thin films to extend the noise suppression bandwidth while maintaining noise suppression performance through pulsed current. However, the method of bandwidth modulation is relatively complex, and its application scenarios are subject to many limitations.

[0006] Therefore, integrating, high-performance, wide-bandwidth, and highly applicable noise suppressors has become an urgent problem for the industry. Summary of the Invention

[0007] To address the aforementioned problems and shortcomings, and to solve the issues of existing noise suppressors in terms of integrability, high performance, wide bandwidth, and high applicability, this invention provides an integrated thin-film noise suppressor that integrates multilayer magnetic thin films with transmission lines in electronic devices. This results in a simple structure that can be easily applied in highly integrated electronic circuits, while also providing a wide noise suppression bandwidth and excellent suppression effect.

[0008] An integrated thin-film noise suppressor has a multilayer thin-film structure, consisting of a dielectric substrate, a transmission line, an insulating layer, and a magnetic thin-film layer from bottom to top.

[0009] The dielectric substrate is an insulating medium, and the transmission line has a conductivity greater than 10. 3 Conductive material with a strength of (S / cm).

[0010] The magnetic thin film layer is composed of n unit layers stacked from bottom to top, where n≥2. Each unit layer is a double-layer structure consisting of a magnetic film with a lower resonant absorption frequency of f1 and an upper isolation layer, where f1 is 0.5GHz-10GHz. The final stack consists of a total of n unit layers of magnetic thin film, and the isolation layer is made of insulating material.

[0011] The insulating layer completely insulates the magnetic thin film layer from the microstrip line.

[0012] Furthermore, the magnetic thin film layer is prepared by magnetron sputtering.

[0013] Furthermore, the transmission line is a microstrip line or a coplanar waveguide, and the characteristic impedance of the transmission line is 50Ω to obtain good impedance matching. The noise suppression performance of the transmission line needs to be less than 10% at GHz frequency to ensure normal transmission of useful signals.

[0014] There are currently three theories that can explain the attenuation mechanism of thin films on noise signals, as follows:

[0015] Firstly, ferromagnetic resonance loss: When the frequency of the microwave magnetic field is the same as the precession frequency of the magnetization intensity of the ferromagnetic material, the energy in the microwave magnetic field is absorbed to the maximum extent by the ferromagnetic material, and the energy is lost through damping. Therefore, when a microwave signal within a certain frequency band passes through, the ferromagnetic resonance phenomenon will occur at a certain frequency point, and energy absorption and loss will occur within a certain range of the ferromagnetic resonance frequency, thereby suppressing electromagnetic noise.

[0016] Secondly, eddy current loss: ferromagnetic thin films generate induced currents under high-frequency alternating magnetic fields; the higher the magnetic field frequency, the stronger the induced current. Therefore, eddy current loss is unavoidable in high-frequency electromagnetic fields. Furthermore, the attenuation of eddy current loss occurs across the entire frequency range, thus affecting the operating signal.

[0017] Thirdly, LC resonant loss: Schematic diagram of the cross-sectional structure of the integrated thin-film noise suppressor of this invention. Figure 2 As can be seen, from top to bottom, the structure consists of a magnetic thin film, an insulating layer, a microstrip line, and a dielectric substrate, forming a multilayer structure. The magnetic thin film is the main source of distributed inductance, while the multilayer structure is the main source of distributed capacitance. The resonant frequency is altered by changing the thickness of the insulating layer and the magnetic thin film.

[0018] For single-layer thin-film noise suppressors, simply increasing the film thickness will reduce the anisotropic field of the film and drastically deteriorate the high-frequency characteristics. Therefore, in this invention, the magnetic film is layered, and each layer of magnetic film is separated by an insulating medium to ensure that there is no coupling between the layers of magnetic film. Thus, when the total thickness of the thin-film noise suppressor is increased, the high-frequency characteristics of the film will not decrease significantly.

[0019] Furthermore, when the magnetic film is made of a single material, the thickness of the magnetic film varies gradually. This gradient structure increases the bandwidth of the thin-film noise suppressor, thereby effectively enhancing its performance.

[0020] For a gradient-variable noise suppressor with a constant magnetic layer thickness and a multilayer noise suppressor with a fixed magnetic layer thickness, the performance variation between different thin-film noise suppressors is small due to the uniform total magnetic layer thickness. However, in a gradient-variable noise suppressor, the different magnetic film layers have different thicknesses, each with a different ferromagnetic resonance absorption frequency, resulting in different noise suppression bandwidths for different magnetic layers. Therefore, the gradient-variable noise suppressor has a wider noise suppression bandwidth.

[0021] Furthermore, the magnetic films of the unit layers in the magnetic thin film layer are made of different materials. Since the ferromagnetic resonance peak frequencies of different materials are different, the desired frequency can be arbitrarily selected to further broaden the bandwidth of the overall magnetic thin film layer.

[0022] This invention integrates multiple layers of soft magnetic thin films on transmission lines through insulation, suppressing noise by utilizing the magnetic loss of the soft magnetic films. It can form integrated thin-film noise suppressors with single or multiple frequencies within the 0-6 GHz frequency range. The noise suppression frequency band can be adjusted according to actual needs (the type of magnetic film material or the thickness of the magnetic film), meeting the requirements for suppressing electromagnetic noise over a wide frequency range. It also overcomes the drawbacks of complex structures in traditional electromagnetic interference (EMI) devices and the large size of non-integrated thin-film noise suppressors. The integrated thin-film noise suppressor can attenuate noise within the GHz band without affecting useful signals, meeting the requirement for suppressing noise harmonics. The fabrication of integrated thin-film noise suppressors is simple and easy to implement by combining thin-film technology and microelectronic lithography.

[0023] In summary, the present invention has a simple structure, meets the requirement of noise suppression under high integration, and has a wide noise suppression frequency band and simple manufacturing process. Attached Figure Description

[0024] Figure 1 This is a top view of the noise attenuation principle and structure of the present invention;

[0025] Figure 2 This is a schematic diagram of the cross-sectional structure of the present invention;

[0026] Figure 3 This is a microstrip line model with a characteristic impedance of 50Ω in the embodiment;

[0027] Figure 4 This is a simulation model of the integrated thin-film noise suppressor from Example 1;

[0028] Figure 5 The simulation results show the conducted noise suppression performance (Ploss / Pin) of the sample in Example 1 as a function of the number of layers n.

[0029] Figure 6 The relationship between S21 and the number of layers n for sample of Example 1;

[0030] Figure 7 The simulation results show the conducted noise suppression performance of the sample in Example 2. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] An integrated thin-film noise suppressor comprises, from bottom to top, a dielectric substrate, a microstrip line, an insulating layer, and a magnetic thin film layer. Its top view and schematic diagram of high-frequency noise attenuation are shown below. Figure 1 As shown, the cross-sectional schematic diagram is as follows: Figure 2 As shown.

[0033] Example 1

[0034] Integrated FeCoB multilayer thin film noise suppressor

[0035] Create a new HFSS project and build a microstrip line model, such as... Figure 3 As shown. Through simulation optimization, the microstrip line parameters were determined so that its characteristic impedance is 50Ω, satisfying the impedance matching condition. The dielectric substrate is FR_4 (relative permittivity = 4.4) with a thickness of 100μm; the microstrip line metal material is Cu with a length of 10mm, a width of 196μm, and a thickness of 18μm.

[0036] FeCoB multilayer magnetic thin films are integrated onto a pre-designed microstrip transmission line through SiO2 insulation. The model structure is as follows: Figure 4As shown, the cross-sectional structure is as follows Figure 2 As shown. The insulating layer is 9.2 mm long, 9.2 mm wide, and 0.2 μm thick. To ensure sufficient insulation during fabrication, the size of the magnetic thin film does not exceed that of the insulating layer. Therefore, the dimensions of the FeCoB multilayer thin film are determined to be 9 mm long, 9 mm wide, and 90 nm thick per layer. The magnetic thin film material parameters are set, and the permeability is substituted into the measured magnetic spectrum.

[0037] Then, the excitation source for the wave port is allocated. In this embodiment, the solution frequency is set to 3 GHz, and a frequency sweep is performed in the range of 0.5 to 6 GHz to run the simulation.

[0038] Figure 5 The simulation results show the conducted noise suppression performance (Ploss / Pin) of the FeCoB multilayer film noise suppressor designed in this embodiment as a function of the number of layers n. Figure 6 The relationship between S21 and the number of layers n for a FeCoB multilayer film noise suppressor. Figure 5 and Figure 6 As can be seen from the simulation of the two-port S-parameter structure, the device structure of this embodiment has very good noise suppression performance.

[0039] For integrated microstrip noise suppressors, when FeCoB multilayer films are used as the magnetic thin film, a resonance peak appears in Ploss / Pin as the number of FeCoB layers increases. The absorption frequency is between 4.5-5 GHz, and the noise suppression performance reaches up to 82.5%. The frequency of the resonance peak gradually decreases as the number of layers increases.

[0040] Example 2

[0041] Integrated FeCoB and FeNi multilayer thin film noise suppressor

[0042] With n=4, the FeCoB multilayer film in Example 1 is replaced to form a 4-layer film of FeCoB / SiO2 / FeNi / SiO2 / FeCoB / SiO2 / FeNi / SiO2, with other three-dimensional dimensions being the same as the FeCoB film in Example 1. Figure 7 The simulation results show the conducted noise suppression performance of the FeCoB and FeNi multilayer thin film noise suppressors used in this embodiment. The simulation results demonstrate that the designed integrated microstrip line noise suppressor improves noise suppression capability at low frequencies and has a larger noise suppression bandwidth compared to the FeCoB multilayer film noise suppressor.

[0043] Example 3

[0044] Gradient-variable FeCoB multilayer thin film noise suppressor

[0045] Example 3 uses the same model parameters as Example 1, except that the magnetic thin film is replaced with a FeCoB multilayer film with a gradually varying magnetic layer thickness. The FeCoB multilayer film is a three-layer film (n=3) with thicknesses of 135 nm, 90 nm, and 45 nm respectively. For a gradient-variable magnetic layer noise suppressor and a multilayer film noise suppressor with a fixed magnetic layer thickness, the performance difference between the two is small due to the same total magnetic layer thickness. However, the gradient-variable noise suppressor has a wider noise suppression bandwidth because each magnetic layer has a different ferromagnetic resonance absorption frequency.

[0046] As can be seen from the above embodiments, this invention integrates multiple layers of soft magnetic films on a transmission line through the isolation of insulating layers. Noise suppression is achieved through the magnetic loss of the soft magnetic films, enabling the formation of integrated thin-film noise suppressors with single or multiple frequencies within the 0-6 GHz frequency range. Furthermore, it provides a preferred solution for adjusting the type or thickness of the magnetic film material according to actual needs to further meet broadband electromagnetic noise suppression requirements. This invention has a simple structure and process, and combines the advantages of integrability, high performance, wide bandwidth, and high applicability.

Claims

1. An integrated thin film noise suppressor, characterized by: For the multilayer thin film structure, from bottom to top are a dielectric substrate, a transmission line, an insulating layer and a magnetic thin film layer; The dielectric substrate is an insulating dielectric and the transmission line is a conductive material having an electrical conductivity greater than 10 3 (S / cm). The magnetic thin film layer is stacked from bottom to top by n unit layers, n≥2, the unit layer is a double-layer structure of a lower layer of magnetic film with a resonance absorption frequency f1 and an upper layer of an isolation layer, f1 is 0.5GHz-10GHz; the final stack is a magnetic thin film layer with a total of n unit layers, the isolation layer uses an insulating material; the unit layer uses FeCoB and FeNi two materials alternately. The insulating layer completely insulates the magnetic thin film layer and the microstrip line.

2. The integrated thin film noise suppressor of claim 1, wherein: The transmission line is a microstrip line or a coplanar waveguide, and the characteristic impedance of the transmission line is 50Ω.

3. The integrated thin film noise suppressor of claim 1, wherein: The magnetic thin film layer is prepared by magnetron sputtering.

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