A broadband high-selectivity hybrid filter integrating microstrip line and acoustic resonator

Abstract

The application discloses a broadband high-selectivity hybrid filter integrating microstrip line and acoustic resonator, comprising a microstrip filter circuit and at least one double-trap network, the microstrip filter circuit is used for constructing a broadband passband response of a target working frequency band, the double-trap network is connected between a main transmission path and a ground wire, and is used for forming double traps near both sides of the passband and introducing transmission poles in the passband range. The double-trap network comprises an acoustic resonator and an inductance element realized through a bonding wire, and the bonding wire realizes electrical connection and provides equivalent inductance at the same time. The filter can balance a relatively wide passband, a narrow transition band and relatively high adjacent band suppression.

Description

Technical Field

[0001] This invention relates to the field of radio frequency filter technology, specifically a broadband high-selectivity hybrid filter integrating microstrip lines and acoustic resonators. Background Technology

[0002] As wireless communication systems rapidly develop towards higher frequencies, wider bandwidths, and higher integration, radio frequency front-ends are placing comprehensive performance requirements on filters, including wide passband, fast roll-off, and high adjacent band rejection, in order to meet the challenges of signal selection and interference suppression in complex electromagnetic environments.

[0003] Microstrip line filters are widely used in broadband filter design due to their simple structure, flexible design, ease of fabrication, and ability to achieve wide passbands. However, bandpass filters built solely using microstrip line structures typically have a gentle passband roll-off and limited adjacent stopband suppression, making it difficult to simultaneously achieve both a wide passband and high frequency selectivity. On the other hand, acoustic resonators, especially bulk acoustic resonators, possess high quality factors and strong frequency selectivity, and are often used to introduce transmission zeros into the filter response to improve roll-off and out-of-band rejection. However, traditional schemes based on a single acoustic resonator can usually only create one transmission zero, lacking the ability to simultaneously optimize both sides of the passband, and still failing to meet the dual requirements of wide bandwidth and high selectivity.

[0004] Furthermore, in the implementation of practical hybrid filters, the bonding wires inevitably introduce parasitic inductance. Existing designs mostly treat this as a disadvantage, mitigating it by shortening the bond length, increasing the number of parallel bonds, or implementing parasitic compensation, rarely utilizing it as a controllable and usable functional inductor. Therefore, how to transform the parasitic inductance of the bonding wires into an equivalent inductance that can participate in the control of the filter response, and how to coordinate it with an acoustic resonator to form a new notch filter structure, thereby achieving wide passband, narrow transition band, and high adjacent band rejection without introducing additional independent lumped inductor elements, remains a pressing technical problem to be solved in this field.

[0005] Therefore, it is necessary to provide a new filter structure to solve the problems of insufficient roll-off of existing broadband filters, limited adjacent stopband suppression, and increased complexity caused by the need to introduce additional inductors in traditional hybrid structures. Summary of the Invention

[0006] This invention aims to overcome the shortcomings of existing broadband filters, such as insufficient roll-off, limited adjacent stopband suppression, and the increased complexity caused by the need to introduce additional independent inductors in traditional hybrid structures. It provides a broadband high-selectivity hybrid filter that can balance wide passband, narrow transition band, and steep roll-off, and is compact and easy to integrate.

[0007] To achieve the above objectives, the technical solution specifically adopted by the present invention is as follows:

[0008] The present invention provides a broadband high-selectivity hybrid filter integrating microstrip lines and acoustic resonators, including a dielectric substrate and a microstrip filter circuit and a dual notch network constructed on the dielectric substrate.

[0009] Specifically, the microstrip filter circuit includes an input port, an output port, and a main transmission path connecting the input port and the output port. A distributed bandpass filter network is connected to the main transmission path. The microstrip filter circuit is used to construct a wideband passband response for the target operating frequency band, providing a wide passband coverage.

[0010] Preferably, the microstrip filter circuit further includes an input matching transmission line and an output matching transmission line. The input matching transmission line is connected between the input port and the distributed bandpass filter network to achieve impedance matching between the input port and the distributed bandpass filter network, thereby reducing signal reflection; the output matching transmission line is connected between the output port and the distributed bandpass filter network to achieve impedance matching between the distributed bandpass filter network and the output port.

[0011] Preferably, the distributed bandpass filter network is composed of coupling lines, which are used to provide the coupling transmission characteristics required to form a bandpass response and are one of the core structures for realizing a wideband passband.

[0012] The dual notch filter network includes an acoustic resonator, a first bonding wire, and a second bonding wire. One end of the first bonding wire is connected to one end of the acoustic resonator, and the other end of the first bonding wire serves as the access end of the dual notch filter network, connected to an access node on the main transmission path. One end of the second bonding wire is connected to the other end of the acoustic resonator, and the other end of the second bonding wire is grounded.

[0013] Preferably, the first and second bonding wires each provide an equivalent inductance, that is, the inherent parasitic inductance of the bonding wires themselves is used as a functional inductor element, without the need to introduce an additional independent lumped inductance. The first and second bonding wires, together with the acoustic resonator, form a resonant branch, which is used to form two transmission zeros near both sides of the passband of the broadband passband response, thereby forming a double notch response to enhance the passband edge roll-off characteristics and improve the adjacent band rejection capability.

[0014] Preferably, the dual notch network further introduces a transmission pole within the passband, which corresponds to the parallel resonant point of the acoustic resonator. This effectively compensates for the insertion loss that may be caused by the introduction of the notch. The positions of the dual notches formed by the dual notch network are synergistically adjusted by the parameters of the acoustic resonator, the equivalent inductance of the first bonding wire, and the equivalent inductance of the second bonding wire. By adjusting the above parameters, the frequency positions of the two notches can be flexibly controlled to adapt to different design requirements for passband roll-off and adjacent band suppression.

[0015] Preferably, at least one of the following parameters is adjustable: the diameter, bonding height, bonding arc structure parameters, and the spacing between the two bonding points of the first and / or second bonding conductors. By adjusting these parameters, the equivalent inductance of the bonding conductors can be changed, thereby achieving precise adjustment of the double notch position and improving the flexibility and adjustability of the design.

[0016] Preferably, a first dual notch network is connected to the access node between the input-end matched transmission line and the distributed bandpass filter network. Alternatively, a first dual notch network is connected to the access node between the input-end matched transmission line and the distributed bandpass filter network, while a second dual notch network is connected to the access node between the distributed bandpass filter network and the output-end matched transmission line. By setting one or more dual notch networks, the passband edge roll-off and adjacent band suppression effects can be enhanced in a stepwise manner.

[0017] Preferably, the microstrip filter circuit further includes a first additional matching transmission line disposed between the input matching transmission line and the distributed bandpass filter network, and a second additional matching transmission line disposed between the distributed bandpass filter network and the output matching transmission line. The access node is located between the first additional matching transmission line and the distributed bandpass filter network, and / or between the second additional matching transmission line and the distributed bandpass filter network. Adding an additional matching transmission line can further optimize impedance matching and provide a more flexible access position for the dual notch filter network.

[0018] Preferably, the acoustic resonator is a bulk acoustic wave (BAW), a surface acoustic wave (SAW), or a Lamb wave resonator, with the thin-film bulk acoustic wave (FBAR) being particularly preferred due to its high quality factor and good frequency selectivity.

[0019] Preferably, the dielectric substrate has a relative permittivity of 3.55 and a dielectric loss tangent of 0.0027, such as Rogers RO4003 substrate, to provide stable high-frequency performance and low dielectric loss.

[0020] This invention has the following characteristics and beneficial effects:

[0021] Balancing broadband and high selectivity: This invention utilizes a microstrip filter circuit to construct a wider passband response for the target frequency band, and forms dual notch transmission zeros near both sides of the passband through an embedded dual notch network. This significantly enhances the roll-off performance at the passband edge and improves the adjacent band suppression capability while maintaining broadband characteristics, achieving synergistic optimization of broadband and high selectivity.

[0022] Improved passband transmission characteristics: The dual notch network can introduce at least one transmission pole in the passband, effectively compensating for the insertion loss that may be caused by the introduction of notches, and improving impedance matching and transmission performance in the passband.

[0023] No additional lumped inductor required, reducing complexity: This invention transforms the equivalent inductance of the bonding wire, which is traditionally considered a parasitic parameter, into a functional inductor. Together with the acoustic resonator, it forms a dual notch network, achieving dual notch response without the need for an additional independent lumped inductor. This simplifies the circuit structure and reduces design costs and manufacturing difficulty.

[0024] Flexible design and highly adjustable: The position of the double notch filter can be coordinated by adjusting the acoustic resonator parameters and structural parameters such as the diameter, bonding height, arc height, and span of the bonding wire, which facilitates optimized design for different center frequencies, bandwidths, and transition band requirements, thus improving the design freedom of the filter.

[0025] Easy to integrate and practical: This hybrid filter can be implemented based on conventional dielectric substrates such as RO4003 and standard bonding processes, is compatible with existing RF front-end processes, and has good prospects for engineering applications. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a hybrid filter provided in Embodiment 1 of the present invention;

[0027] Figure 2 This is a schematic diagram of the bonding wire structure used in this invention;

[0028] Figure 3 for Figure 2 Simulation diagram of the equivalent inductance of the bonded wire;

[0029] Figure 4 for Figure 1 Simulation diagrams of S-parameters and impedance response of a double notch filter network;

[0030] Figure 5 The simulation results of the S-parameters of the hybrid filter provided in Example 1 are shown in the figure.

[0031] Figure 6 This is a schematic diagram of a hybrid filter provided in Embodiment 2 of the present invention;

[0032] Figure 7 This is a planar structure diagram of the hybrid filter provided in Embodiment 2 of the present invention;

[0033] Figure 8 This is a simulation comparison chart of the S-parameters of the hybrid filter provided in Example 2 and Example 1;

[0034] Figure 9 This is a schematic diagram of the hybrid filter circuit provided in Embodiment 3 of the present invention;

[0035] Figure 10 This is a physical diagram of the hybrid filter provided in Embodiment 3 of the present invention;

[0036] Figure 11 This is a schematic diagram of the filter S-parameter response provided in Embodiment 3 of the present invention.

[0037] Figure Labels

[0038] 100. Microstrip filter circuit; 101. Input port; 102. Output port; 103. Input matching transmission line; 104. Output matching transmission line; 105. Distributed bandpass filter network; 105-1. Coupler line; 106. First additional matching transmission line; 107. Second additional matching transmission line; 201. First double notch network; 201-1. First bonding wire; 201-2. Acoustic resonator; 201-3. Second bonding wire; 202. Second double notch network. Detailed Implementation

[0039] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0040] Example 1

[0041] This embodiment provides a broadband, high-selectivity hybrid filter integrating microstrip lines and acoustic resonators, such as... Figure 1 As shown, it includes a dielectric substrate and a microstrip filter circuit and a dual notch network constructed on the dielectric substrate.

[0042] Specifically, in this embodiment, the dielectric substrate is Rogers RO4003 material with a relative permittivity of 3.55, a dielectric loss tangent of 0.0027, and a thickness of 0.813 mm. The bottom layer of the dielectric substrate is a metal ground plane, and the top layer is equipped with a microstrip filter circuit and a dual notch filter network.

[0043] In this embodiment, the microstrip filter circuit 100 includes an input port 101, an output port 102, and a main transmission path connecting the input port and the output port. A distributed bandpass filter network 105 is connected to the main transmission path. Specifically, both the input port 101 and the output port 102 are RF connector interfaces with a characteristic impedance of 50Ω and a port width of 1.27mm.

[0044] Furthermore, the main transmission path includes an input matching transmission line 103, a distributed bandpass filter network 105, and an output matching transmission line 104. The input matching transmission line 103 connects the input port 101 and the distributed bandpass filter network 105, with a line width of 3.1 mm and a length of 11.25 mm. The output matching transmission line 104 connects the distributed bandpass filter network 105 and the output port 102, with a line width of 3.1 mm and a length of 11.25 mm. The distributed bandpass filter network 105 consists of a coupling line 105-1 with a line width of 0.15 mm, a length of 14.9 mm, and a coupling line spacing of 0.93 mm.

[0045] Furthermore, the dual notch filter network includes an acoustic resonator 201-2, a first bonding wire 201-1, and a second bonding wire 201-3. The acoustic resonator 201-2 is a thin-film bulk acoustic resonator (FBAR), with its parallel resonant frequency designed near the passband center frequency. One end of the first bonding wire 201-1 is connected to one end of the acoustic resonator 201-2, and the other end serves as the access point of the dual notch filter network, connected to an access node on the main transmission path. One end of the second bonding wire 201-3 is connected to the other end of the acoustic resonator 201-2, and the other end is grounded through a grounding pad and a metal via on the dielectric substrate.

[0046] Location of the access node: In this embodiment, the access node is located between the input matching transmission line 103 and the distributed bandpass filter network 105. That is, the first bonding wire 201-1 of the dual notch filter network is connected between this node and the acoustic resonator.

[0047] like Figure 2 The diagram shows a schematic of the bonding wire structure used in this invention. The parameters of the bonding wire are as follows: both the first and second bonding wires are made of gold wire, with a diameter d = 1 mil (approximately 25.4 μm), bonding angles a = 50° and b = 50°, arc heights h1 = 0.3 mm and h2 = 0.5 mm, and the distance between the two bonding points w = 1.3 mm. Under the above parameters, the simulation results of the equivalent inductance of the bonding wire are as follows. Figure 3 As shown. The above parameters can be adjusted as needed to change the equivalent inductance value.

[0048] Understandably, microstrip filter circuits construct a broadband passband response. In the dual notch network 201, the first bonding wire 201-1 and the second bonding wire 201-3 provide equivalent inductance, which, together with the acoustic resonator 201-2, constitutes the resonant branch. For example... Figure 4 The figure shows the simulation results of the S-parameters and impedance response of the double notch filter network. Curve 02 represents the impedance response curve of the double notch filter network, and curve 03 represents the S-parameter response curve of the double notch filter network. Figure 4 It can be seen that this resonant branch generates two transmission zeros in the frequency response, thus forming a double notch response, located near both sides of the passband, which significantly enhances the passband edge roll-off characteristics and improves adjacent band rejection. At the same time, a transmission pole is introduced near the parallel resonant point of the acoustic resonator within the passband, improving in-band insertion loss and impedance matching.

[0049] Furthermore, by changing parameters such as the thickness and area of ​​the acoustic resonator's diaphragm, or adjusting parameters such as the diameter, bonding height, arc structure, and span of the bonding wires, the position of the double notch can be changed in a coordinated manner to adapt to different filter specifications.

[0050] Through simulation, such as Figure 5 The figure shows the S-parameter simulation results of the hybrid filter provided in this embodiment, where curve 04 represents the frequency response curve of the microstrip filter circuit, and curve 05 represents the frequency response curve of the hybrid filter after embedding the first dual notch network. Figure 5 It can be seen that after embedding the first dual notch network 201, the filter forms a dual notch response near the passband edge, thereby reducing the transition band bandwidth corresponding to the attenuation of the filter from the passband edge to 20dB by 620MHz, and reducing the insertion loss at the low-frequency edge of the passband by about 0.8dB.

[0051] It should be further noted that in this embodiment, a physical sample is fabricated on the RO4003 substrate according to the above structure. The input and output ports use SMA connectors, the bonding wires are gold wires, and the acoustic resonator is a thin-film bulk acoustic resonator (FBAR).

[0052] Example 2

[0053] The difference between this embodiment and Embodiment 1 is that, as Figure 6 As shown, a second double notch network is added to form a symmetrical structure, which further enhances the passband edge roll-off and adjacent band suppression capabilities.

[0054] The hybrid filter in this embodiment includes the same dielectric substrate, microstrip filter circuit, first dual notch network 201 and second dual notch network 202 as in Embodiment 1.

[0055] The microstrip filter circuit is basically the same as that in Embodiment 1, including an input port 101, an output port 102, an input matching transmission line 103, a distributed bandpass filter network 105, and an output matching transmission line 104, wherein the distributed bandpass filter network 105 is composed of coupling lines 105-1. The dimensional parameters of each part are the same as those in Embodiment 1.

[0056] like Figure 7 The diagram shown is a planar structure diagram of the hybrid filter provided in this embodiment. W1 represents the port width of the input port or output port, W2 represents the line width of the input matching transmission line or output matching transmission line, W3 represents the line width of the coupling line, L1 represents the port length of the input port or output port, L2 represents the length of the input matching transmission line or output matching transmission line, L3 represents the length of the coupling line, and S1 represents the line spacing of the coupling line.

[0057] More specifically, W1 can be 1.27 mm, W2 can be 3.1 mm, W3 can be 0.15 mm, L1 can be 4.7 mm, L2 can be 11.25 mm, L3 can be 14.9 mm, and S1 can be 0.93 mm.

[0058] Access points for the two double notch filters:

[0059] The access node of the first dual notch filter network 201 is located between the input matching transmission line 103 and the distributed bandpass filter network 105. One end of its first bonding wire is connected to this node, and the other end is connected to the acoustic resonator; the second bonding wire connects the acoustic resonator to ground.

[0060] The access node of the second dual notch filter network 202 is located between the distributed bandpass filter network 105 and the output matching transmission line 104. One end of its third bonding wire is connected to this node, and the other end is connected to its own acoustic resonator; the fourth bonding wire connects the acoustic resonator to ground.

[0061] Component parameters of the two double notch filters: The acoustic resonators in the two double notch filters can be designed with the same or different resonant frequencies, and the bonding wire parameters can also be adjusted independently. In this embodiment, the two acoustic resonators use the same thin-film bulk acoustic resonator, and the bonding wire parameters are the same as in Embodiment 1 to ensure the symmetry of the filter response.

[0062] Understandably, the signal enters the distributed bandpass filter network 105 from input port 101 via input matching transmission line 103, and then reaches output port 102 via output matching transmission line 104. The first dual notch filter network 201 introduces a dual notch response near the passband edge, and the second dual notch filter network 202 further enhances this notch response in the same frequency band. The synergistic effect of the two dual notch filter networks makes the passband edge roll-off steeper, further improving adjacent band rejection capability. Simultaneously, each dual notch filter network introduces a transmission pole within the passband range, further compensating for in-band insertion loss.

[0063] Compared to Example 1, the transition band bandwidth corresponding to the attenuation from the passband edge to 20dB in this example is reduced by 60MHz, while the adjacent stopband rejection is improved by approximately 5dB, and the insertion loss at the low-frequency edge of the passband is reduced by approximately 0.2dB. Simulation results are as follows. Figure 8 As shown, curve 05 represents the simulation result of Example 1, and curve 06 represents the simulation result of this example. The comparison clearly shows that the latter has better roll-off and suppression performance.

[0064] Example 3

[0065] This embodiment is based on embodiment 2, such as Figure 9 and Figure 10 As shown, a first additional matching transmission line 106 and a second additional matching transmission line 107 are further added to optimize impedance matching and provide a more flexible access location for the dual notch network.

[0066] The hybrid filter in this embodiment includes a dielectric substrate, a microstrip filter circuit, a first dual notch network 201, and a second dual notch network 202. The microstrip filter circuit, based on embodiment 2, adds a first additional matching transmission line 106 and a second additional matching transmission line 107.

[0067] Specific connection relationships:

[0068] The output of the input-matched transmission line 103 is connected to the input of the first additional matched transmission line 106, and the output of the first additional matched transmission line 106 is connected to the input of the distributed bandpass filter network 105. The line width is 4mm and the length is 7mm.

[0069] The output of the distributed bandpass filter network 105 is connected to the input of the second additional matching transmission line 107, and the output of the second additional matching transmission line 107 is connected to the input of the output matching transmission line 104. The line width is 4mm and the length is 7mm.

[0070] The access node of the first dual notch filter network 201 is located between the first additional matched transmission line 106 and the distributed bandpass filter network 105. That is, the first bonding wire of the first dual notch filter network is connected to this node.

[0071] The access node of the second double notch filter network 202 is located between the second additional matched transmission line 107 and the distributed bandpass filter network 105. That is, the first bonding wire of the second double notch filter network is connected to this node.

[0072] In this embodiment, the additional matching transmission line can further transform the input / output impedance of the distributed bandpass filter network to a value that is more convenient for the dual notch filter network to access, thereby improving the impact of the dual notch filter network on the main transmission path and obtaining a flatter passband ripple. At the same time, the additional matching transmission line also provides additional design freedom, so that the access node of the dual notch filter network is no longer limited to the position where the matching transmission line and the coupling line are directly connected, but can be located between the additional matching transmission line and the coupling line.

[0073] The filter provided in this embodiment, while maintaining the same passband bandwidth and roll-off characteristics as Embodiment 2, reduces the insertion loss at the high-frequency edge of the passband by approximately 0.2 dB, and the overall return loss within the passband is better than 14 dB. This indicates that the structure can further reduce in-band ripple and improve in-band transmission characteristics, making it particularly suitable for applications requiring high in-band flatness and insertion loss.

[0074] like Figure 11 The diagram shown illustrates the S-parameter test results provided in this embodiment. Testing of the physical sample of the hybrid filter reveals that the filter maintains a wide passband response within the target operating frequency band and exhibits a significant roll-off at the passband edge, indicating that the dual notch network enhances adjacent-band suppression.

[0075] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A broadband, high-selectivity hybrid filter integrating a microstrip line and an acoustic resonator, characterized in that, Includes a dielectric substrate and a microstrip filter circuit and a dual notch network constructed on the dielectric substrate; The microstrip filter circuit (100) includes an input port (101), an output port (102), and a main transmission path connected between the input port (101) and the output port (102), wherein a distributed bandpass filter network (105) is connected to the main transmission path. The dual notch filter network (201) includes an acoustic resonator (201-2), a first bonding wire (201-1), and a second bonding wire (201-3). One end of the first bonding wire (201-1) is connected to one end of the acoustic resonator (201-2), and the other end of the first bonding wire (201-1) serves as the access end of the dual notch filter network and is connected to the access node on the main transmission path. One end of the second bonding wire (201-3) is connected to the other end of the acoustic resonator (201-2), and the other end of the second bonding wire (201-3) is grounded. The first bonding wire (201-1) and the second bonding wire (201-3) each provide equivalent inductance and together with the acoustic resonator (201-2) form a resonant branch to form a double notch near both sides of the passband of the broadband passband response, so as to enhance the passband edge roll-off characteristics and improve the adjacent band rejection capability.

2. The broadband high-selectivity hybrid filter integrating microstrip line and acoustic resonator according to claim 1, characterized in that, The microstrip filter circuit (100) also includes: An input matching transmission line (103) is connected between the input port (101) and the distributed bandpass filter network (105); The output matching transmission line (104) is connected between the output port (102) and the distributed bandpass filter network (105).

3. A broadband high-selectivity hybrid filter integrating microstrip line and acoustic resonator according to claim 1, characterized in that, The distributed bandpass filter network (105) is composed of coupling lines (105-1).

4. A broadband high-selectivity hybrid filter integrating microstrip line and acoustic resonator according to claim 1, characterized in that, The dual notch network is also used to introduce a transmission pole in the passband to improve in-band insertion loss and impedance matching.

5. A broadband high-selectivity hybrid filter integrating a microstrip line and an acoustic resonator according to claim 1, characterized in that, The position of the double notch formed by the double notch network is adjusted by the parameters of the acoustic resonator (201-2), the equivalent inductance of the first bonding wire (201-1), and the equivalent inductance of the second bonding wire (201-3).

6. A broadband high-selectivity hybrid filter integrating microstrip line and acoustic resonator according to claim 5, characterized in that, The diameter, bonding height, bonding arc structure parameters, and spacing between two bonding points of the first bonding conductor (201-1) and / or the second bonding conductor (201-3) are at least one of adjustable parameters. The equivalent inductance can be adjusted by adjusting the parameters, thereby adjusting the position of the double notch filter.

7. A broadband high-selectivity hybrid filter integrating microstrip line and acoustic resonator according to claim 2, characterized in that, The access node between the input matching transmission line (103) and the distributed bandpass filter network (105) is connected to a first double notch network (201).

8. A broadband high-selectivity hybrid filter integrating microstrip line and acoustic resonator according to claim 2, characterized in that, The access node between the input matching transmission line (103) and the distributed bandpass filter network (105) is connected to a first double notch network (201), and the access node between the distributed bandpass filter network (105) and the output matching transmission line (104) is connected to a second double notch network (202).

9. A broadband high-selectivity hybrid filter integrating a microstrip line and an acoustic resonator according to claim 7 or 8, characterized in that, The microstrip filter circuit (100) further includes a first additional matching transmission line (106) disposed between the input matching transmission line (103) and the distributed bandpass filter network (105), and a second additional matching transmission line (107) disposed between the distributed bandpass filter network (105) and the output matching transmission line (104).

10. A broadband high-selectivity hybrid filter integrating a microstrip line and an acoustic resonator according to claim 9, characterized in that, The access node is located between the first additional matched transmission line (106) and the distributed bandpass filter network (105), and / or between the second additional matched transmission line (107) and the distributed bandpass filter network (105).

11. A broadband high-selectivity hybrid filter integrating microstrip line and acoustic resonator according to claim 1, characterized in that, The acoustic resonator (201-2) is a bulk acoustic wave resonator, a surface acoustic wave resonator, or a Lamb wave resonator.

12. A broadband high-selectivity hybrid filter integrating microstrip line and acoustic resonator according to claim 1, characterized in that, The dielectric substrate has a relative permittivity of 3.55 and a dielectric loss tangent of 0.0027.

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