A large bandwidth filter with excellent roll-off and integrated module

Abstract

This invention discloses a wide-bandwidth filter and integrated module with excellent roll-off, belonging to the field of radio frequency communication technology. The filter includes a first module, a second module, and a third module. The first module is an acoustic module, composed of several acoustic resonators connected in series. The second module is an acoustic-electric hybrid module, including several parallel-grounded branches composed of inductors and acoustic resonators. The third module is an electrical module, composed of LC components connected in parallel to ground. The acoustic resonators in the first module achieve high suppression near the right end of the passband, while the acoustic resonators in the second module achieve high suppression near the left end of the passband. The inductors are used for impedance matching with the acoustic resonators to enhance out-of-band suppression. The LC components in the third module are used to construct the passband and achieve wideband characteristics. This invention comprehensively improves the out-of-band suppression performance of the filter and solves the problems of poor roll-off and insufficient bandwidth of traditional LC filters and acoustic filters.

Description

Technical Field

[0001] This invention relates to the field of radio frequency communication technology, and in particular to a large bandwidth filter and integrated module with excellent roll-off. Background Technology

[0002] In existing technologies, the fifth-generation traditional RF filters globally mainly include LC filters and filters based on acoustic resonators. LC filters, composed of inductors and capacitors, are easy to design to achieve a wide passband, thus offering advantages in broadband filtering applications. However, due to the relatively limited quality factors of inductors and capacitors, LC filters exhibit a gentle roll-off at the passband edge, making it difficult to further improve near-end rejection performance. Filters based on acoustic resonators, such as surface acoustic wave (SAW) filters, bulk acoustic wave (BAW) filters, and thin-film BAW filters, rely on the high quality factors of the resonators to achieve steeper roll-off characteristics and better out-of-band rejection performance. However, limited by the electromechanical coupling coefficient of piezoelectric materials and the intrinsic characteristics of the devices, the bandwidth of these filters is typically narrow, making it difficult to meet the high-bandwidth application requirements of the N79 band.

[0003] Therefore, how to provide a filter suitable for the N79 frequency band that has both large bandwidth and excellent roll-off characteristics has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a wide-bandwidth filter and integrated module with excellent roll-off, so as to solve the problems in the prior art where LC filters are difficult to achieve high near-end suppression and acoustic filters are difficult to achieve wide bandwidth.

[0005] To achieve the above objectives, the present invention provides a wide bandwidth filter with excellent roll-off, comprising a first module, a second module, and a third module; The first module is an acoustic module, which includes several acoustic resonators connected in series. The second module is an acoustic-electric hybrid module, which includes several parallel grounded branches. Each of the parallel branches includes an acoustic resonator and an inductor assembly. Each parallel branch of the second module is connected to different connection nodes and / or filter ports of the first module. The third module is an electrical module, which includes several parallel grounding branches composed of LC components. Each parallel branch of the third module is connected to a different connection node of the first module. The acoustic resonator is connected in series and / or in parallel with the LC component so that the filter forms at least one transmission zero.

[0006] Preferably, the acoustic resonators in the first module include: a first acoustic resonator, a second acoustic resonator, a third acoustic resonator, a fourth acoustic resonator, and a fifth acoustic resonator; Wherein, the first end of the first acoustic resonator serves as the first end of the filter, and the second end of the first acoustic resonator is connected to the first end of the second acoustic resonator; The second end of the second acoustic resonator is connected to the first end of the third acoustic resonator; The second end of the third acoustic resonator is connected to the first end of the fourth acoustic resonator; The second end of the fourth acoustic resonator is connected to the first end of the fifth acoustic resonator; The second end of the fifth acoustic resonator serves as the second end of the filter.

[0007] Preferably, the acoustic resonators in the second module include: a sixth acoustic resonator, a seventh acoustic resonator, and an eighth acoustic resonator; the inductor components in the second module include: a first inductor, a second inductor, a third inductor, a fourth inductor, a fifth inductor, and a sixth inductor. Wherein, the first end of the sixth acoustic resonator is connected to the first end of the filter, the second end of the sixth acoustic resonator is connected to the first end of the second inductor, and the second end of the second inductor is grounded; the first inductor is connected in parallel across the two ends of the sixth acoustic resonator; The first end of the seventh acoustic resonator is connected to the connection node between the first acoustic resonator and the second acoustic resonator; the second end of the seventh acoustic resonator is connected to the first end of the fourth inductor; and the second end of the fourth inductor is grounded. The third inductor is connected in parallel to both ends of the seventh acoustic resonator. The first end of the eighth acoustic resonator is connected to the connection node between the second acoustic resonator and the third acoustic resonator. The second end of the eighth acoustic resonator is connected to the first end of the sixth inductor, and the second end of the sixth inductor is grounded. The fifth inductor is connected in parallel to both ends of the eighth acoustic resonator.

[0008] Preferably, the third module includes a first LC component and a second LC component; The first LC component includes: a first capacitor, a second capacitor, a seventh inductor, and an eighth inductor; The second LC component includes: a third capacitor and a ninth inductor; Wherein, the first terminal of the first capacitor is connected to the connection node of the third acoustic resonator and the fourth acoustic resonator, the second terminal of the first capacitor is connected to the first terminal of the seventh inductor, the second terminal of the seventh inductor is connected to the first terminal of the eighth inductor, and the second terminal of the eighth inductor is grounded; the second capacitor is connected in parallel across the two terminals of the seventh inductor; The first terminal of the third capacitor is connected to the connection node between the fourth acoustic resonator and the fifth acoustic resonator, and this node is marked as point M. The second terminal of the third capacitor is grounded. The ninth inductor is connected in parallel across the two terminals of the third capacitor.

[0009] Preferably, a plurality of acoustic resonators are connected in series between the second end of the fourth acoustic resonator and point M.

[0010] Preferably, the acoustic resonators are all thin-film bulk acoustic resonators; wherein the acoustic resonators in the first module are of the same type, and the acoustic resonators in the second module are of the same type.

[0011] The present invention also provides an integrated module, the integrated module including a filter.

[0012] Therefore, the beneficial effects of the present invention using the above-mentioned large bandwidth filter and integrated module with excellent roll-off are as follows: (1) The present invention constructs a hybrid filter structure combining an acoustic module, an acoustic-electric hybrid module and an electrical module by coordinating the LC element with the acoustic resonator; wherein, the acoustic resonator in the first module is used to achieve high suppression at the near end of the right passband, and the acoustic resonator in the second module is used to achieve high suppression at the near end of the left passband; the LC element in the second and third modules is used to perform impedance matching with the acoustic resonator to improve the flatness in the passband and widen the passband width.

[0013] (2) Based on the interaction between the LC element and the acoustic resonator, the present invention can form at least one transmission zero at the edge of the passband to enhance near-end suppression, and form at least one transmission zero at a position far from the passband to improve far-end suppression, thereby realizing a filter with large bandwidth, high out-of-band suppression and excellent roll-off characteristics suitable for the N79 frequency band.

[0014] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0015] Figure 1 This is a circuit schematic diagram of a large bandwidth filter with excellent roll-off according to a first embodiment of the present invention; Figure 2 This is a schematic diagram of the simulation results of the S-parameters of the acoustic resonators R1-R5 in Example 1; Figure 3 This is a schematic diagram of the simulation results of the S-parameters of the R6-R8 acoustic resonator in Example 1; Figure 4 This is a schematic diagram of the simulation results for Example 1; Figure 5 This is a circuit schematic diagram of a second embodiment of a large bandwidth filter with excellent roll-off of the present invention; Figure 6 This is a schematic diagram of the simulation results for Example 2.

[0016] Figure Labels 101. Module 1; 102. Module 2; 103. Module 3; R1. First acoustic resonator; R2. Second acoustic resonator; R3. Third acoustic resonator; R4. Fourth acoustic resonator; R5. Fifth acoustic resonator; R6. Sixth acoustic resonator; L1. First inductor; L2. Second inductor; L3. Third inductor; L4. Fourth inductor; L5. Fifth inductor; L6. Sixth inductor; L7. Seventh inductor; L8. Eighth inductor; L9. Ninth inductor; C1. First capacitor; C2. Second capacitor; C3. Third capacitor. Detailed Implementation

[0017] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0019] Example 1: like Figure 1As shown, this invention provides a wide-bandwidth filter with excellent roll-off, comprising a first module 101, a second module 102, and a third module 103. The first module 101 is an acoustic module consisting of five acoustic resonators, used to achieve high suppression near the right end of the passband. The second module 102 is an acoustic-electric hybrid module consisting of three parallel grounded branches, each including an acoustic resonator and an inductor assembly. The acoustic resonator is used to achieve high suppression near the left end of the passband, and the inductor assembly is used for impedance matching with the acoustic resonator to improve flatness within the passband and to form at least one transmission zero outside the band to enhance out-of-band suppression. The third module 103 is an electrical module including two parallel grounded branches composed of LC components, used to construct the passband and achieve broadband characteristics.

[0020] The first module 101 consists of five identical thin-film bulk acoustic resonators connected in series, as shown in the simulation results diagram below. Figure 2 As shown. The specific connection method of the first module 101 is as follows: the first end of the first acoustic resonator R1 serves as the first end of the filter; the second end of the first acoustic resonator R1 is connected to the first end of the second acoustic resonator R2; the second end of the second acoustic resonator R2 is connected to the first end of the third acoustic resonator R3; the second end of the third acoustic resonator R3 is connected to the first end of the fourth acoustic resonator R4; the second end of the fourth acoustic resonator R4 is connected to the first end of the fifth acoustic resonator R5; the second end of the fifth acoustic resonator R5 serves as the second end of the filter.

[0021] The three parallel grounding branches of the second module 102 are arranged side by side, and the branch structures are identical, differing only in the inductance parameters of each branch. Each parallel branch includes one acoustic resonator and two inductors. All three acoustic resonators are identical thin-film bulk acoustic resonators, as illustrated in the simulation results diagram below. Figure 3 As shown. The specific connection method of the second module 102 is as follows: the first end of the sixth acoustic resonator R6 is connected to the first end of the filter, the second end is grounded through the second inductor L2, and the first inductor L1 is connected in parallel to the two ends of the sixth acoustic resonator R6; the first end of the seventh acoustic resonator R7 is connected to the connection node of the first acoustic resonator R1 and the second acoustic resonator R2, the second end is grounded through the fourth inductor L4, and the third inductor L3 is connected in parallel to the two ends of the seventh acoustic resonator R7; the first end of the eighth acoustic resonator R8 is connected to the connection node of the second acoustic resonator R2 and the third acoustic resonator R3, the second end is grounded through the sixth inductor L6, and the fifth inductor L5 is connected in parallel to the two ends of the eighth acoustic resonator R8.

[0022] The two parallel grounding branches of the third module 103 respectively include a first LC component and a second LC component. The first LC component includes a first capacitor C1, a second capacitor C2, a seventh inductor L7 and an eighth inductor L8; the second LC component includes a third capacitor C3 and a ninth inductor L9.

[0023] In the first LC assembly, the first terminal of the first capacitor C1 is connected to the connection node of the third acoustic resonator R3 and the fourth acoustic resonator R4, and the second terminal is grounded through the seventh inductor L7 and the eighth inductor L8 in sequence. The second capacitor C2 is connected in parallel across the two ends of the seventh inductor L7. In the second LC assembly, the first terminal of the third capacitor C3 is connected to the connection node of the fourth acoustic resonator R4 and the fifth acoustic resonator R5, and the second terminal is grounded. The ninth inductor L9 is connected in parallel across the two ends of the third capacitor C3.

[0024] Based on the above structure, the acoustic resonator in the first module 101 is used to achieve high near-end suppression on the right side of the passband, and the acoustic resonator in the second module 102 is used to achieve high near-end suppression on the left side of the passband. The inductor and LC components in the second module 102 and the third module 103 are used to perform impedance matching with the acoustic resonator to improve the flatness within the passband and construct a wideband passband. At the same time, based on the interaction between the inductor and LC components and the acoustic resonator, at least one transmission zero can be formed at the edge of the passband and at least one transmission zero can be formed at a position far from the passband, thereby improving the near-end and far-end out-of-band suppression performance of the filter.

[0025] Figure 4 The diagram shown is a simulation result of the filter circuit structure of this embodiment. It can be seen that the filter circuit structure of this embodiment can simultaneously meet the characteristics of large bandwidth (passband of 4.4GHz-5GHz) and excellent roll-off (greater than 5.15GHz, suppression of 35dB).

[0026] Example 2: This embodiment is basically the same as Embodiment 1, except that the number of acoustic resonators in the filter has been adjusted in this embodiment.

[0027] like Figure 5 As shown, the filter provided in this embodiment still includes a first module, a second module, and a third module. Unlike Embodiment 1, the first module in this embodiment includes six acoustic resonators connected in series; that is, the filter uses a larger number of acoustic resonators to form the acoustic module.

[0028] Specifically, the first module is still located in the series path of the filter to form the main transmission path of the filter; the second and third modules are still located in the parallel branch and connected to the corresponding connection nodes of the first module to achieve impedance matching, passband construction and out-of-band suppression enhancement.

[0029] In this embodiment, by increasing the number of acoustic resonators in the first module, the frequency response characteristics of the filter can be further adjusted, thereby providing another alternative solution for the implementation of filter structures under different design specifications.

[0030] Figure 6 The diagram shown is a simulation result of the filter circuit structure in this embodiment. Figure 6 As can be seen, the filter in this embodiment can achieve a passband of 4.4GHz-5.0GHz and a suppression of 35dB above 5.15GHz, thus meeting the requirements of large bandwidth while having excellent roll-off characteristics.

[0031] Therefore, this invention employs a wide-bandwidth filter and integrated module with excellent roll-off, solving the core pain points of poor roll-off in traditional LC filters and insufficient bandwidth in acoustic filters. Through partitioned suppression design and multi-transmission zero collaboration, it simultaneously improves near-end and far-end out-of-band suppression performance. Precise impedance matching is achieved through inductor and LC components, with passband insertion loss less than 2dB and amplitude flatness better than 0.5dB. The number of components can be flexibly adjusted to meet different performance and cost requirements, adapting to various 5G RF communication scenarios.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A wide-bandwidth filter with excellent roll-off, characterized in that: It includes Module 1, Module 2, and Module 3; The first module is an acoustic module, which includes several acoustic resonators connected in series. The second module is an acoustic-electric hybrid module, which includes several parallel grounded branches. Each of the parallel branches includes an acoustic resonator and an inductor assembly. Each parallel branch of the second module is connected to different connection nodes and / or filter ports of the first module. The third module is an electrical module, which includes several parallel grounding branches composed of LC components. Each parallel branch of the third module is connected to a different connection node of the first module. The acoustic resonator is connected in series and / or in parallel with the LC component so that the filter forms at least one transmission zero.

2. A large bandwidth filter with excellent roll-off as described in claim 1, characterized in that: The acoustic resonators in the first module include: a first acoustic resonator (R1), a second acoustic resonator (R2), a third acoustic resonator (R3), a fourth acoustic resonator (R4), and a fifth acoustic resonator (R5); Wherein, the first end of the first acoustic resonator (R1) serves as the first end of the filter, and the second end of the first acoustic resonator (R1) is connected to the first end of the second acoustic resonator (R2). The second end of the second acoustic resonator (R2) is connected to the first end of the third acoustic resonator (R3); The second end of the third acoustic resonator (R3) is connected to the first end of the fourth acoustic resonator (R4); The second end of the fourth acoustic resonator (R4) is connected to the first end of the fifth acoustic resonator (R5); The second end of the fifth acoustic resonator (R5) serves as the second end of the filter.

3. A wide-bandwidth filter with excellent roll-off as described in claim 2, characterized in that: The acoustic resonators in the second module include: a sixth acoustic resonator (R6), a seventh acoustic resonator (R7), and an eighth acoustic resonator (R8); the inductor components in the second module include: a first inductor (L1), a second inductor (L2), a third inductor (L3), a fourth inductor (L4), a fifth inductor (L5), and a sixth inductor (L6). Wherein, the first end of the sixth acoustic resonator (R6) is connected to the first end of the filter, the second end of the sixth acoustic resonator (R6) is connected to the first end of the second inductor (L2), and the second end of the second inductor (L2) is grounded; the first inductor (L1) is connected in parallel to the two ends of the sixth acoustic resonator (R6); The first end of the seventh acoustic resonator (R7) is connected to the connection node between the first acoustic resonator (R1) and the second acoustic resonator (R2). The second end of the seventh acoustic resonator (R7) is connected to the first end of the fourth inductor (L4), and the second end of the fourth inductor (L4) is grounded. The third inductor (L3) is connected in parallel across the two ends of the seventh acoustic resonator (R7). The first end of the eighth acoustic resonator (R8) is connected to the connection node of the second acoustic resonator (R2) and the third acoustic resonator (R3). The second end of the eighth acoustic resonator (R8) is connected to the first end of the sixth inductor (L6), and the second end of the sixth inductor (L6) is grounded. The fifth inductor (L5) is connected in parallel to both ends of the eighth acoustic resonator (R8).

4. A wide-bandwidth filter with excellent roll-off as described in claim 3, characterized in that: The third module includes a first LC component and a second LC component; The first LC component includes: a first capacitor (C1), a second capacitor (C2), a seventh inductor (L7), and an eighth inductor (L8); The second LC component includes: a third capacitor (C3) and a ninth inductor (L9); Wherein, the first terminal of the first capacitor (C1) is connected to the connection node of the third acoustic resonator (R3) and the fourth acoustic resonator (R4), the second terminal of the first capacitor (C1) is connected to the first terminal of the seventh inductor (L7), the second terminal of the seventh inductor (L7) is connected to the first terminal of the eighth inductor (L8), and the second terminal of the eighth inductor (L8) is grounded; the second capacitor (C2) is connected in parallel across the two ends of the seventh inductor (L7); The first terminal of the third capacitor (C3) is connected to the connection node between the fourth acoustic resonator (R4) and the fifth acoustic resonator (R5), and this node is marked as point M. The second terminal of the third capacitor (C3) is grounded. The ninth inductor (L9) is connected in parallel across the two ends of the third capacitor (C3).

5. A large bandwidth filter with excellent roll-off as described in claim 4, characterized in that: Several acoustic resonators are connected in series between the second end of the fourth acoustic resonator (R4) and point M.

6. A large bandwidth filter with excellent roll-off as described in claim 1, characterized in that: All acoustic resonators are thin-film bulk acoustic resonators; wherein, the acoustic resonators in the first module are of the same type, and the acoustic resonators in the second module are of the same type.

7. An integrated module, characterized in that, The integrated module includes the filter as described in any one of claims 1-6.

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