YIG film-based adaptive on-chip filter and design method thereof

Abstract

The application provides a YIG film-based adaptive on-chip filter and a design method thereof.The filter comprises a YIG film-loaded four-port transducing structure, a terminal matching network and a front-end matching network, the YIG film-loaded four-port transducing structure is composed of two parallel microstrip transmission lines and a YIG film covering the two parallel microstrip transmission lines, the two ends of the parallel microstrip transmission lines are the ports of the YIG film-loaded four-port transducing structure, the YIG film is used for converting electromagnetic waves into static magnetic surface waves, the terminal matching network is connected with two diagonal ports of the YIG film-loaded four-port transducing structure respectively, and the front-end matching network is connected with the other two diagonal ports of the YIG film-loaded four-port transducing structure, namely an input port and an output port.Through the terminal matching design and the front-end impedance matching network design, the application significantly reduces the insertion loss of the device under a low-power signal.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microwave devices and magnetism, and particularly to an adaptive on-chip filter based on YIG film and a design method thereof. BACKGROUND

[0002] YIG film material has been widely used in the research of adaptive radio frequency filters in recent years due to its excellent magnetic properties, low loss characteristics, and nonlinear response to radio frequency signal power. The filter based on YIG material can control the operating frequency through a magnetic field, and has the potential to dynamically suppress strong interference signals without causing loss to low-power useful signals, showing good application prospects. However, the existing adaptive filter based on YIG film still faces problems such as high insertion loss, narrow operating frequency band, and insufficient integration under low-power signal conditions, which makes it difficult to meet the needs of the new generation of wireless communication systems in terms of high dynamic range, wide frequency band, miniaturization, and high integration. Therefore, it is urgent to develop new structural designs, improve device performance, further tap the potential of YIG film in radio frequency power adaptive filtering, and improve its filtering performance and system compatibility in complex electromagnetic environments. SUMMARY

[0003] To solve the above technical problems, the present application proposes an adaptive on-chip filter based on YIG film and a design method thereof. The present application designs a double-ended matching network for the YIG film loaded four-port transduction structure, which can significantly reduce the insertion loss and expand the bandwidth of the adaptive on-chip filter.

[0004] An adaptive on-chip filter based on YIG film, comprising a YIG film loaded four-port transduction structure, a terminal matching network, and a front-end matching network. The YIG film loaded four-port transduction structure is composed of two parallel microstrip transmission lines and a YIG film covering them. The two ends of the parallel microstrip transmission lines are the ports of the YIG film loaded four-port transduction structure. The YIG film is used to convert electromagnetic waves into static magnetic surface waves. The terminal matching network connects two opposite ports of the YIG film loaded four-port transduction structure, and the front-end matching network connects the other two opposite ports, i.e., the input port and the output port.

[0005] To optimize the technical solution, the further improvement scheme is as follows:

[0006] The front-end matching network is a π-type microstrip network or a binomial multi-section matching transformer.

[0007] A design method of an adaptive on-chip filter based on YIG film, for designing the adaptive on-chip filter based on YIG film described above, specifically comprising the following steps:

[0008] Step one, modeling and parameter extraction of YIG film loaded four-port transduction structure: obtain the size parameters of YIG film and parallel microstrip transmission line, cover YIG film on the parallel microstrip transmission line to form YIG film loaded four-port transduction structure, measure the S parameters of YIG film loaded four-port transduction structure by vector network analyzer combined with de-embedding technology, and import the simulation platform to establish the YIG film loaded four-port transduction structure model;

[0009] Step two, design of double-end impedance matching network: the terminal matching network connects two diagonal ports of the YIG film loaded four-port transduction structure model through microstrip radial stub, realizes the wideband adaptation of the terminal impedance of the YIG film loaded four-port transduction structure, and the front-end matching network connects the other two diagonal ports of the YIG film loaded four-port transduction structure model, that is, the input port and the output port, and the front-end matching network is used to match the input / output impedance to 50Ω.

[0010] Step three, optimize the layout size of the YIG film loaded four-port transduction structure model with double-end impedance matching network and joint simulation, and complete the design of the adaptive on-chip filter based on YIG film.

[0011] Compared with the prior art, the present application has the following remarkable advantages:

[0012] Through the terminal matching design and the front-end impedance matching network design, the present application significantly reduces the insertion loss of the device under low power signal. The test results show that the designed adaptive on-chip filter mainly works in the L band under low power signal, and

[0013] The test results show that when the input power exceeds the power threshold (-20 dBm), the adaptive on-chip filter can automatically generate frequency selective notch, attenuate the high power signal in a certain range to about -30 dBm, and the selectivity bandwidth is not more than 3.32 MHz, which verifies the ability of dynamic suppression of interference signals.

[0014] The experiment verifies the regulation effect of external magnetic field on the working frequency band and working performance of the filter, and the working frequency band of the filter can be dynamically tuned by adjusting the bias magnetic field strength.

[0015] For low power signals, when the magnetic field strength increases from 100 Oe to 150 Oe, the center frequency of the filter shifts to high frequency, the bandwidth shrinks but the insertion loss further decreases; on the contrary, when the magnetic field strength decreases to 50 Oe, the bandwidth expands but the loss slightly increases. When the magnetic field strength is 100 Oe, the device has the best comprehensive performance in the L band (1~2 GHz), and the bandwidth and insertion loss reach the best balance.

[0016] For high power signals, adjusting the magnetic field strength will change the operating frequency band of the filter, but will not have a significant impact on the attenuation of high power signals. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 (a) is an adaptive on-chip filter of a π-type front-end matching network (design 1), and (b) is an adaptive on-chip filter of a binomial 3-section matching transformer front-end matching network (design 2);

[0018] Figure 2 is an input-output characteristic curve of design 1;

[0019] Figure 3 is a frequency selection characteristic curve of design 1;

[0020] Figure 4 (a) is the S parameter test result of design 1 when a low power signal is input, and (b) is the S parameter test result of design 2 when a low power signal is input;

[0021] Figure 5 (a) is the S parameter test result of design 1 when a high power signal is input, and (b) is the S parameter test result of design 2 when a high power signal is input;

[0022] Figure 6 (a) is the S parameter result of design 1 when a low power signal is input and the bias magnetic field strength is changed, and (b) is the S parameter result of design 2 when a low power signal is input and the bias magnetic field strength is changed. 21 21

[0023] The reference signs in the drawings are as follows: π-type microstrip network 1, YIG film loaded four-port transducer structure 2, terminal matching network 3, binomial multi-section matching transformer 4. DETAILED DESCRIPTION

[0024] The embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0025] As shown in Figure 1 , an adaptive on-chip filter based on a YIG film according to the present application comprises a YIG film loaded four-port transducer structure 2, a terminal matching network 3, and a front-end matching network.

[0026] The YIG film loaded four-port transducer structure 2 is composed of two parallel microstrip transmission lines and a YIG film covering the same, and the YIG film is used to convert electromagnetic waves into a static magnetic surface wave.

[0027] ​​Terminal matching network 3 connects two ports of YIG film loaded four-port transducing structure 2, and wideband impedance matching is realized by using microstrip radial stub.

[0028] Front-end matching network connects input port and output port of YIG film loaded four-port transducing structure 2, and the front-end matching network is π-type microstrip network 1 or binomial three-section matching transformer 4, which is used for matching input / output impedance to 50 Ω.

[0029] The application also provides a design method of the adaptive on-chip filter based on the YIG film, and the design method comprises the following steps:

[0030] The design flow is as follows:

[0031] YIG film loaded four-port transducing structure 2 modeling and parameter extraction: structure: a YIG film with a thickness of 10 um and an area of 10 mm*10 mm is used as a load and is covered on two microstrip lines with a length of 10 mm, a width of 0.1 mm and a spacing of 6 mm to form a four-port transducing structure; parameter extraction: the S parameters of the YIG film loaded four-port transducing structure 2 are measured by using a vector network analyzer combined with de-embedding technology, and the device model is established in an ADS2023 simulation platform.

[0032] Double-end impedance matching network design: terminal matching network 3: the terminal matching network 3 connects two ports of the YIG film loaded four-port transducing structure 2, and a microstrip radial stub is used, and the parameters satisfy: radial width Wi = 0.5 mm, radial length L = 2 mm, and fan angle Angle = 75°, so that the wideband adaptation of the transducer terminal impedance is realized, signal reflection is reduced, and the working bandwidth is expanded; front-end matching network: the terminal matching network connects the input port and the output port of the YIG film loaded four-port transducing structure 2, and a π-type microstrip network or a binomial three-section matching transformer composed of a microstrip line is used to match the input / output impedance to 50 Ω.

[0033] Layout optimization and joint simulation: the layout size is reduced by using the curved microstrip line.

[0034] Figure 1 (a) in the figure is the adaptive on-chip filter design of the front-end matching network using the π-type microstrip network 1, Figure 1(b) in the figure is the adaptive on-chip filter design with binomial 3-section matching network, the difference between the two is that the former uses different design method for the front-end matching network. Accompanied by the signal input and the application of 100 Oe bias magnetic field to the YIG film, the electromagnetic wave is converted into the magnetostatic surface wave by the YIG film, and since the electromagnetic wave cannot be completely converted into the magnetostatic surface wave, a part of the electromagnetic wave will be reflected in the transduction structure area, resulting in the reflection coefficient S 11 and the insertion loss is high, through the double-end matching design, the reflection coefficient and the insertion loss have been greatly optimized.

[0035] Figure 2 is the input-output characteristic curve of the No. 1 design, from the figure, it can be seen that when the low-power signal is input, the attenuation of the filter to the signal is linear. When the input signal power increases to about -20 dBm, the attenuation of the filter to the input signal power becomes nonlinear, which is the power threshold of the device. The result shows that the adaptive on-chip filter can pass the low-power signal while limiting the high-power signal.

[0036] Figure 3 is the frequency selection characteristic curve of the No. 1 design, a high-power signal with a frequency of 1.5 GHz and an amplitude of 0 dBm is input, and a low-power input signal with an amplitude of -30 dBm is swept in the range of 1.48 GHz to 1.52 GHz, from the figure, it can be seen that far from 1.5 GHz, the low-power signal fluctuates less, the closer to 1.5 GHz, the faster the low-power signal drops, and reaches the minimum value near 1.5 GHz, when the drop is 3 dB, the bandwidth between the two points corresponding to the selected bandwidth, from the test result, the selected bandwidth is 3.32 MHz.

[0037] Figure 4 (a) in the figure is the S parameter test result of the No. 1 design when the bias magnetic field is 100 Oe, the input low-power signal is -30 dBm, -25 dBm and -20 dBm. Observing the S 21 parameter, it can be seen that the passband of the No. 1 design is 1.32~2.1 GHz, and in the passband, the curve is relatively flat. When the low-power signal is -30 dBm and -25 dBm, the curves are approximately coincident, and the value fluctuates between -5~-8 dB. Observing the S 11 parameter, it can be seen that in the passband, the highest is not more than -6 dB.

[0038] Figure 4(b) is the S parameter test result of design 2 when the bias magnetic field is 100 Oe and the input low power signal is -30 dBm, -25 dBm, and -20 dBm. 21 The parameters show that the passband of design No. 2 is 1.3~2.1 GHz. The curve is relatively flat. When the low power signal is -30 dBm and -25 dBm, The curves are nearly overlapped, and their values ​​fluctuate between -4 and -7 dB. 11 It can be seen from the parameters that within the passband, The maximum value does not exceed -6 dB. It indicates the input reflection coefficient when the output terminal is matched, reflecting the impedance matching performance of the filter; It represents the forward transmission gain under the condition of output termination matching, reflecting the transmission efficiency of the filter.

[0039] Figure 5 (a) in the figure is the S-parameter test results of design No. 1 when the bias magnetic field is 100 Oe and the input high power signal is -20 dBm, -15 dBm, -10 dBm, -5 dBm, and 0 dBm. Figure 5 (b) is the S parameter test result of design 2 when the bias magnetic field is 100 Oe and the input high power signal is -20 dBm, -15 dBm, -10 dBm, -5 dBm, and 0 dBm. Figure 5 As shown in (a) and (b), when the input is a high power signal, It decreases with the increase of input power, which reflects the adaptive filtering characteristics of the adaptive on-chip filter. At the same time, it can be seen from the shapes of the curves in the two figures that the two different design methods have similar effects on the performance of the adaptive on-chip filter in limiting high-power signals.

[0040] Figure 6 (a) is the S of design No. 1 when the input low power signal is -30 dBm and the magnetic field strength is different. 21 parameter. Figure 6 (b) is the S of Design 2 when the input low power signal is -30 dBm and the magnetic field strength is different. 21 Parameters. As can be seen from the figure, as the applied magnetic field strength increases, the main operating frequency band of the filter moves to high frequency. When H0 = 50 Oe, the bandwidth increases by 200 MHz compared to H0 = 100 Oe, but When H0 = 150 Oe, the bandwidth is reduced by 300 MHz compared to H0 = 100 Oe, but The bandwidth and S 21 The bandwidth and S

[0041] The above is only the preferred embodiment of the present application, the protection scope of the present application is not limited to the above-mentioned examples, all technical solutions belonging to the idea of the present application are within the protection scope of the present application. It should be pointed out that, for ordinary skilled in the art, some improvements and refinements without departing from the principles of the present application, should be considered as the protection scope of the present application.

Claims

1. An adaptive on-chip filter based on YIG film, characterized in that: It includes a YIG film loaded four-port transducer structure (2), a terminal matching network (3) and a front-end matching network. The YIG film loaded four-port transducer structure (2) is composed of two parallel microstrip transmission lines and a YIG film covering the two ends of the parallel microstrip transmission lines as ports of the YIG film loaded four-port transducer structure (2). The film is used to convert electromagnetic waves into static magnetostatic surface waves. The terminal matching network (3) is respectively connected to two diagonal ports of the YIG film loaded four-port transducer structure (2). The front-end matching network is connected to the other two diagonal ports of the YIG film loaded four-port transducer structure (2), namely the input port and the output port. The front-end matching network is a π-type microstrip network (1) or a binomial multi-section matching converter (4). The π-type microstrip network (1) or the binomial multi-section matching converter (4) is composed of three sections of curved microstrip lines. The front-end matching network is connected to the YIG film loaded four-port transducer structure (2) through a section of curved microstrip line. The terminal matching network (3) is a fan-shaped structure and uses a microstrip radial stub to connect the two diagonal ports of the YIG film loaded four-port transducer structure (2).

2. A design method for an adaptive on-chip filter based on a YIG film, characterized by: The method for designing the adaptive on-chip filter based on the YIG film as claimed in claim 1 specifically comprises the following steps: Step 1. Modeling and parameter extraction of the YIG film loaded four-port transducer structure (2): Obtain the size parameters of the YIG film and the parallel microstrip transmission line, cover the YIG film on the parallel microstrip transmission line to form the YIG film loaded four-port transducer structure (2), measure the S parameters of the YIG film loaded four-port transducer structure (2) by using a vector network analyzer combined with de-embedding technology, and import it into the simulation platform to establish a YIG film loaded four-port transducer structure model; Step 2: Design a two-terminal impedance matching network: The terminal matching network uses a microstrip radial stub to connect the two diagonal ports of the YIG film loaded four-port transducer structure model to achieve broadband adaptation of the terminal impedance of the YIG film loaded four-port transducer structure (2). The front-end matching network connects the other two diagonal ports of the YIG film loaded four-port transducer structure model, namely the input port and the output port. The front-end matching network is used to match the input / output impedance to 50Ω. Step 3: Optimize the layout size and conduct joint simulation on the YIG film loaded four-port transducer structure model with a two-terminal impedance matching network to complete the design of the adaptive on-chip filter based on YIG film.

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