Filter and multiplexer comprising the same

Abstract

This disclosure provides a filter and a multiplexer including the same. The filter according to this disclosure includes: at least one series resonator unit connected in series between an input node and an output node, comprising a series resonator or comprising a series resonator and an inductor and / or capacitor connected in parallel or in series therewith; and at least one parallel resonator unit connected in parallel between a connection node and a ground node, comprising a parallel resonator or comprising a parallel resonator and an inductor and / or capacitor connected in parallel or in series therewith, the connection node being a node at the input and / or output of at least one series resonator unit and / or at least one parallel resonator unit being a composite resonator comprising a resonator. The filter according to this disclosure and the multiplexer including the filter can form more out-of-band transmission zeros in the filter's frequency response curve, thereby enhancing out-of-band attenuation.

Description

Technical Field

[0001] This disclosure relates to the field of electronic circuit technology, and in particular, to filters and multiplexers including such filters. Background Technology

[0002] With the development of wireless communication applications, people have increasingly higher requirements for data transmission rates. Corresponding to these higher data transmission rates is the need for higher utilization of spectrum resources and greater spectrum complexity. The increasing complexity of communication protocols places stringent demands on the performance of various aspects of radio frequency (RF) systems. In the RF front-end module, RF filters and multiplexers play a crucial role, filtering out out-of-band interference and noise to meet the signal-to-noise ratio requirements of the RF system and communication protocols. With the increasing commercialization of 5G, the demand for multiplexers such as B1, B2, B3, B5, B7, and B8 is also growing significantly.

[0003] Currently, filters and multiplexers based on thin-film bulk acoustic resonators (FBARs) are increasingly widely used due to their advantages such as low insertion loss, steep transition characteristics, high selectivity, high power capacity, and strong electrostatic discharge (ESD) resistance.

[0004] However, the rapid development of wireless communication technology has led to increasingly scarce frequency resources, with frequency bands allocated to different signals becoming increasingly close together. This results in problems such as mutual interference between signals and system instability, necessitating filters with better out-of-band attenuation performance to meet information transmission requirements. However, existing trapezoidal filters have limited attenuation capabilities in certain frequency bands due to the limited number of transmission zeros.

[0005] Therefore, there is still a need in the prior art for a filter that can increase the number of out-of-band transmission zeros in the frequency response curve to enhance out-of-band attenuation, as well as a multiplexer constructed using the filter. Summary of the Invention

[0006] A brief overview of this disclosure is given below to provide a basic understanding of certain aspects thereof. However, it should be understood that this overview is not an exhaustive summary of this disclosure, nor is it intended to identify key or essential parts of this disclosure, nor is it intended to limit the scope of this disclosure. The purpose of this overview is merely to present some inventive concepts of this disclosure in a simplified form as a prelude to the more detailed description that follows.

[0007] The purpose of this disclosure is to provide a filter that can increase the number of out-of-band transmission zeros in the frequency response curve to enhance out-of-band attenuation, and a multiplexer constructed using the filter.

[0008] According to one aspect of this disclosure, a filter is provided, comprising: at least one series resonator unit connected in series between an input node and an output node, the series resonator unit comprising a series resonator or comprising a series resonator and an inductor and / or capacitor connected in parallel or in series with the series resonator; and at least one parallel resonator unit connected in parallel between a connection node and a ground node between the input node and the output node, the connection node being a node at the input and / or output end of the at least one series resonator unit, the parallel resonator unit comprising a parallel resonator or comprising a parallel resonator and an inductor and / or capacitor connected in parallel or in series with the parallel resonator, wherein at least one of the at least one series resonator unit and / or at least one parallel resonator unit is a composite resonator comprising multiple resonators.

[0009] According to embodiments of this disclosure, at least one of the plurality of resonators included in the composite resonator is connected in parallel with an inductor.

[0010] According to embodiments of this disclosure, a composite resonator is used to increase the number of out-of-band transmission zeros in the frequency response curve of a filter.

[0011] According to embodiments of this disclosure, the composite resonator includes multiple resonators that have the same resonant frequency.

[0012] According to embodiments of this disclosure, the composite resonator includes multiple resonators that have different resonant frequencies from each other.

[0013] According to embodiments of this disclosure, a portion of the plurality of resonators included in a composite resonator have the same resonant frequency, while the remaining portions have different resonant frequencies.

[0014] According to embodiments of this disclosure, each of the plurality of resonators included in the series resonator, parallel resonator, and composite resonator is a bulk acoustic resonator.

[0015] According to embodiments of this disclosure, the composite resonator includes a first resonator, a second resonator, a third resonator, and a first inductor. The first resonator and the second resonator are connected in series, the first inductor and the first resonator are connected in parallel, and the third resonator and the second resonator are connected in parallel.

[0016] According to embodiments of this disclosure, the composite resonator further includes a second inductor, which is connected in parallel with the second resonator.

[0017] According to embodiments of the present disclosure, the composite resonator includes a first resonator, a second resonator, a third resonator, and a fourth resonator. The first resonator and the fourth resonator are connected in series, the second resonator is connected in parallel with the first resonator and the fourth resonator, and the third resonator is connected in parallel with the fourth resonator.

[0018] According to embodiments of this disclosure, at least one of the first resonator, the second resonator, and the third resonator is connected in parallel with an inductor.

[0019] According to embodiments of the present disclosure, at least one of the at least parallel resonator units is a composite resonator including a first resonator, a second resonator, a third resonator, and a fourth resonator, wherein the first resonator and the fourth resonator are connected in series and the third resonator and the fourth resonator are connected in parallel, and the input terminal of the second resonator is connected to the connection node to which the composite resonator is connected, and the output terminal is connected to any other connection node.

[0020] According to embodiments of this disclosure, at least one of the first resonator, the second resonator, and the third resonator is connected in parallel with an inductor.

[0021] According to another aspect of this disclosure, a multiplexer is provided, which includes the filter according to the above aspects of this disclosure.

[0022] According to the filter disclosed herein and the multiplexer including the filter, more out-of-band transmission zeros can be formed in the frequency response curve of the filter, thereby enhancing out-of-band attenuation. Attached Figure Description

[0023] The accompanying drawings are included to provide a further understanding of this disclosure and are incorporated in and form a part of this specification. The drawings illustrate embodiments of this disclosure and, together with the following description, serve to illustrate the principles of this disclosure.

[0024] Figure 1 An equivalent circuit diagram of a trapezoidal filter according to the prior art is shown.

[0025] Figure 2 An equivalent circuit diagram of a filter including a composite resonator according to a first embodiment of the present disclosure is shown.

[0026] Figure 3 A comparison graph showing the frequency response curves of a filter including a composite resonator according to a first embodiment of the present disclosure and a trapezoidal filter according to the prior art is shown.

[0027] Figure 4 Another equivalent circuit diagram of a filter including a composite resonator according to a first embodiment of the present disclosure is shown.

[0028] Figure 5 An equivalent circuit diagram of a composite resonator according to a second embodiment of the present disclosure is shown.

[0029] Figure 6 An equivalent circuit diagram of a composite resonator according to a third embodiment of the present disclosure is shown.

[0030] Figure 7 An equivalent circuit diagram of a composite resonator according to a fourth embodiment of the present disclosure is shown. Detailed Implementation

[0031] In this specification, it will also be understood that when an element is referred to relative to other elements, such as “on,” “connected to,” or “coupled to” other elements, that element may be directly disposed on, directly connected to, or directly coupled to that element, or there may be an intervening third element. Conversely, when an element is referred to in this specification relative to other elements, such as “directly” on, directly connected to, or directly coupled to other elements, there is no intervening element between them.

[0032] The present disclosure will now be described more fully below with reference to the accompanying drawings, in which various embodiments are illustrated. However, the present disclosure may be implemented in many different ways and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that the disclosure will be exhaustive and complete, and will fully convey the scope of the disclosure to those skilled in the art. The same reference numerals denote the same elements throughout the drawings. Furthermore, in the drawings, the thickness, proportions, and dimensions of components are enlarged for clarity.

[0033] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the terms “a,” “an,” “the,” and “at least one” as used herein are not intended to limit the quantity but are intended to include both singular and plural forms. For example, unless the context clearly indicates otherwise, “an element” has the same meaning as “at least one element.” “At least one” should not be construed as limited to the quantity “a.” “Or” means “and / or.” The term “and / or” includes any and all combinations of at least one of the associated listed items.

[0034] Unless otherwise specified, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art. Terms defined in commonly used dictionaries shall be interpreted as having the same meaning as in the relevant technical context, and shall not be construed as having a formal meaning in an idealized or overly formal sense unless expressly defined in the specification.

[0035] The meaning of “includes” or “contains” is to specify a nature, quantity, step, operation, element, component, or combination thereof, but does not exclude other natures, quantities, steps, operations, elements, components, or combinations thereof.

[0036] This document describes embodiments with reference to cross-sectional views as idealized implementations. Thus, variations in shape relative to the illustrations are anticipated as a result of, for example, manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the regions shown herein, but should include deviations in shape due to, for example, manufacturing processes. For example, regions shown or described as flat may typically have rough and / or non-linear characteristics. Furthermore, acute angles shown may be rounded. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to show precise shapes of the regions and are not intended to limit the scope of the claims.

[0037] In the following description, exemplary embodiments according to this disclosure will be described with reference to the accompanying drawings.

[0038] Figure 1 An equivalent circuit diagram of a ladder filter 100 according to the prior art is shown.

[0039] like Figure 1 As shown, filter 100 may include resonators B11 to B18 and matching inductors L11 to L16. Resonators B11 to B14 are connected in series between the input node IN and the output node OUT, and are therefore also called series resonators. At least one of the series resonators B11 to B14 may also be connected in parallel or in series with an inductor, thereby forming a corresponding series resonator unit. Resonators B15 to B18 are connected in parallel between the connection nodes C11, C12, C13 and C14 between the input node IN and the output node OUT and the ground node GND, respectively, and are therefore also called parallel resonators. At least one of the parallel resonators B15 to B18 may be connected in parallel or in series with an inductor, thereby forming a corresponding parallel resonator unit. For example, parallel resonators B15 to B18 are connected to the ground node GND by being connected in series with inductors L11 to L14, thereby forming corresponding parallel resonator units.

[0040] The resonant frequency of a resonator when its impedance reaches its minimum value is called the series resonant frequency, and the resonant frequency when its impedance reaches its maximum value is called the parallel resonant frequency. Generally, the series resonant frequency of a resonator is lower than its parallel resonant frequency. All series resonators B11 to B14 have the same series resonant frequency, and their parallel resonant frequencies are also the same. All parallel resonators B15 to B18 have the same series resonant frequency, and their parallel resonant frequencies are also the same. The parallel resonant frequencies of parallel resonators B15 to B18 can be equal to or close to the series resonant frequencies of series resonators B11 to B14.

[0041] In signal processing systems, when the system input amplitude is non-zero and the input frequency causes the system output to be zero, this input frequency value is called the transmission zero. The transmission zero has a decisive influence on the in-band loss and out-of-band attenuation of the filter.

[0042] In filter 100, the number and location of transmission zeros are jointly determined by the series and parallel resonant frequencies of each resonator B11 to B18. Therefore, by adjusting parameters such as the area and thickness of each resonator B11 to B18, the series and parallel resonant frequencies of each resonator B11 to B18 can be adjusted, thereby adjusting the number and location of transmission zeros in the filter.

[0043] Figure 2 An equivalent circuit diagram of a filter 200 including a composite resonator B25 according to a first embodiment of the present disclosure is shown.

[0044] like Figure 2 As shown, according to an embodiment of this disclosure, the filter 200 includes: four series resonators B21 to B24 connected in series between the input node IN and the output node OUT; three parallel resonators B26 to B28 and inductors L22 to L24 connected in series with them, respectively connected in parallel between the connection nodes C22 to C24 between the input node IN and the output node OUT and the ground node GND; and a composite resonator B25 connected in parallel between the connection node C21 between the input node IN and the output node OUT and the ground node GND, wherein the parallel resonator B25 is a composite resonator composed of three resonators B251 to B253 and one inductor L251. In other words, Figure 2 The composite resonator B25 shown replaces Figure 1 The parallel resonator units B15 and L11 are shown.

[0045] Those skilled in the art should recognize that, although Figure 2 The filter 200 shown has four series resonator units and four parallel resonator units, wherein each of the series and parallel resonator units includes a resonator or includes a resonator and a matching inductor and / or capacitor connected in parallel or series with the resonator, but this disclosure is not limited thereto. Those skilled in the art may use other numbers of series and parallel resonator units according to specific application scenarios and design requirements, and all such variations should be covered within the scope of this disclosure.

[0046] like Figure 2 As shown, according to an embodiment of the present disclosure, the composite resonator B25 includes a first resonator B251, a second resonator B252, a third resonator B253, and a first inductor L251. The first resonator B251 and the second resonator B252 are connected in series, the first inductor L251 is connected in parallel with the first resonator B251, and the third resonator B253 is connected in parallel with the second resonator B252.

[0047] According to embodiments of this disclosure, compared to Figure 1 The parallel resonator units B15 and L11 shown, and the impedance curve of the composite resonator B25 have multiple series resonant frequencies and multiple parallel resonant frequencies. Therefore, the composite resonator B25 can increase the number of out-of-band transmission zeros in the frequency response curve of the filter 200.

[0048] Figure 3 A comparison graph is shown of the frequency response curves of a filter 200 including a composite resonator B25 according to a first embodiment of the present disclosure and a trapezoidal filter 100 according to the prior art. Figure 3 The thin lines in the diagram show the frequency response curve of the trapezoidal filter 100 according to the prior art, while the thick lines show the frequency response curve of the filter 200 including the composite resonator B25 according to the first embodiment of the present disclosure.

[0049] like Figure 3 As shown, compared to the frequency response curve of filter 100, the frequency response curve of filter 200 adds three transmission zeros outside the band, namely TZ1, TZ2 and TZ3, thereby enhancing the overall out-of-band attenuation performance.

[0050] According to embodiments of this disclosure, the three resonators B251 to B253 included in the composite resonator B25 may have the same resonant frequency. Alternatively, the three resonators B251 to B253 may also have different resonant frequencies. Alternatively, any two of the three resonators B251 to B253 may have the same resonant frequency, while the remaining resonator may have a different resonant frequency than the aforementioned two resonators.

[0051] Despite the combination Figure 2 The example shown is the replacement of the composite resonator B25. Figure 1 The parallel resonator units B15 and L11 shown illustrate a first embodiment of this disclosure; however, according to the technical concept of this disclosure, a composite resonator can also be used instead. Figure 1 The series resonator unit shown is shown.

[0052] Figure 4 Another equivalent circuit diagram of a filter 200 including a composite resonator B22 according to a first embodiment of the present disclosure is shown. Figure 4 Zhongyu Figure 2 The same elements shown are indicated by the same reference numerals, and for the sake of brevity, the details of these same elements are not described repeatedly here.

[0053] like Figure 4 As shown, with Figure 2 different, Figure 1The series inductor unit B12 shown is replaced by a composite resonator B22. According to an embodiment of this disclosure, the composite resonator B22 includes a first resonator B221, a second resonator B222, a third resonator B223, and a first inductor L221. The first resonator B221 and the second resonator B222 are connected in series, the first inductor L221 and the first resonator B221 are connected in parallel, and the third resonator B223 and the second resonator B222 are connected in parallel.

[0054] According to embodiments of this disclosure, the configuration Figure 2 Each of the series resonator units B21 to B24 and the parallel resonator units B25 to B28 and L11 to L14 of the filter 200 shown can be replaced with a composite resonator as described above.

[0055] Furthermore, according to embodiments of this disclosure, the resonant frequencies of each resonator B251 to B253 constituting the composite resonator B25 are different from the resonant frequencies of the other parallel resonators B26 and B27. Similarly, the resonant frequencies of each resonator B221 to B223 constituting the composite resonator B22 are different from the resonant frequencies of the other series resonators B21, B23, and B24.

[0056] Furthermore, according to embodiments of this disclosure, each of the parallel resonators, series resonators, and resonators constituting the composite resonator included in the filter is a bulk acoustic resonator.

[0057] Despite the above combination Figure 2 and Figure 4 The circuit topology shown, in which the composite resonator has three resonators and one inductor, describes a first embodiment of the present disclosure, but the present disclosure is not limited thereto. According to embodiments of the present disclosure, the composite resonator may also have other forms of circuit topology, which can similarly achieve the formation of more out-of-band transmission zeros in the frequency response curve of the filter, thereby enhancing the technical effect of out-of-band attenuation.

[0058] The following is combined with Figures 5 to 7 Describes composite resonators according to other embodiments of this disclosure.

[0059] Figure 5 An equivalent circuit diagram of the composite resonator B35 according to a second embodiment of the present disclosure is shown. Figure 5 Zhongyu Figure 2 The same elements shown are denoted by the same reference numerals, and for the sake of brevity, details of these same elements are not described repeatedly here. Figure 2 , Figure 5 The composite resonator B35 shown can be replaced Figure 2 The composite resonator B25 in the middle.

[0060] The difference between the composite resonator B35 and the composite resonator B25 according to the second embodiment of this disclosure is that the composite resonator B35 further includes a second inductor L252, which is connected in parallel with the second resonator B252.

[0061] Figure 6 An equivalent circuit diagram of a composite resonator B45 according to a third embodiment of the present disclosure is shown. Figure 6 Zhongyu Figure 2 The same elements shown are denoted by the same reference numerals, and for the sake of brevity, details of these same elements are not described repeatedly here. Figure 2 , Figure 6 The composite resonator B45 shown can be replaced Figure 2 The composite resonator B25 in the middle.

[0062] According to a third embodiment of the present disclosure, the composite resonator B45 includes a first resonator B451, a second resonator B452, a third resonator B453, and a fourth resonator B454. The first resonator B451 and the fourth resonator B454 are connected in series, the second resonator B452 is connected in parallel with the first resonator B451 and the fourth resonator B454, and the third resonator B453 is connected in parallel with the fourth resonator B454.

[0063] Furthermore, despite Figure 6 Not shown, but according to the third embodiment of this disclosure, at least one of the first resonator B451, the second resonator B452 and the third resonator B453 may also be connected in parallel with an inductor.

[0064] Furthermore, although the above text uses the same combination Figures 5 to 6 The parallel resonator units included in the composite resonator replacement filter shown illustrate the second to fourth embodiments of this disclosure, but this disclosure is not limited thereto. Those skilled in the art will recognize that... Figures 5 to 6 The structure of the composite resonator shown can also be adapted to replace the series resonator unit included in the filter, and all such variations should be covered within the scope of this disclosure.

[0065] Figure 7 An equivalent circuit diagram of the composite resonator B57 according to the fourth embodiment of the present disclosure is shown. Figure 7 Zhongyu Figure 2 The same elements shown are denoted by the same reference numerals, and for the sake of brevity, details of these same elements are not described repeatedly here. Figure 2 , Figure 7 The composite resonator B57 shown can be replaced Figure 2Parallel resonator units B27 and L23 in the middle.

[0066] According to the fourth embodiment of this disclosure, the composite resonator B57 includes a first resonator B571, a second resonator B572, a third resonator B573, and a fourth resonator B574. The first resonator B571 and the fourth resonator B574 are connected in series, and the third resonator B573 and the fourth resonator B574 are connected in parallel. The input terminal of the second resonator B572 is connected to the connection node C23 of the composite resonator B57, and the output terminal is connected to the connection node C22 of the parallel resonator units B26 and L22.

[0067] According to embodiments of this disclosure, the output terminal of the second resonator B572 can be connected to any other connection node. For example, the output terminal of the second resonator B572 can be connected to any one of connection nodes C21, C22, and C24.

[0068] Furthermore, despite Figure 7 Not shown, but according to the fourth embodiment of this disclosure, at least one of the first resonator B571, the second resonator B572 and the third resonator B573 may also be connected in parallel with an inductor.

[0069] Furthermore, according to the third and fourth embodiments of this disclosure, the resonant frequencies of the first, second, third, and fourth resonators may be different from each other or may be partially the same. Additionally, when an inductor is connected in parallel to the first, second, and third resonators, the resonant frequencies of the first to fourth resonators may be the same.

[0070] Furthermore, according to embodiments of this disclosure, a multiplexer is also provided, which includes the filter according to the above embodiments of this disclosure.

[0071] According to the filter disclosed herein and the multiplexer including the filter, more out-of-band transmission zeros can be formed in the frequency response curve of the filter, thereby enhancing out-of-band attenuation.

[0072] Although this disclosure has been described with reference to exemplary embodiments thereof, those skilled in the art will understand that various modifications and variations may be made without departing from the spirit and scope of this disclosure as set forth in the claims.

Claims

1. A filter comprising: at least one series resonator unit connected in series between an input node and an output node, the series resonator unit comprising a series resonator or comprising a series resonator and an inductor and / or a capacitor connected in parallel or in series with the series resonator; and at least one parallel resonator unit connected in parallel between a connection node and a ground node, the connection node being a node at an input and / or an output of the at least one series resonator unit, the parallel resonator unit comprising a parallel resonator or comprising a parallel resonator and an inductor and / or a capacitor connected in parallel or in series with the parallel resonator, wherein at least one of the at least one series resonator unit and / or the at least one parallel resonator unit is a composite resonator comprising a plurality of resonators; wherein the composite resonator comprises a first resonator, a second resonator, and a third resonator, and a first inductor, and wherein the first resonator is connected in series with the second resonator, the first inductor is connected in parallel with the first resonator, and the third resonator is connected in parallel with the second resonator. The composite resonator is used to increase the number of out-of-band transmission zeros in a frequency response curve of the filter.

2. The filter of claim 1, wherein, The plurality of resonators comprised in the composite resonator have the same resonant frequency, or the plurality of resonators comprised in the composite resonator have different resonant frequencies from each other, or a portion of the plurality of resonators comprised in the composite resonator have the same resonant frequency, and the remaining portion have different resonant frequencies.

3. The filter of claim 1, wherein, Each of the series resonator, the parallel resonator, and the plurality of resonators comprised in the composite resonator is a bulk acoustic wave resonator.

4. The filter of claim 1, wherein, 5. The filter of claim 1, The composite resonator further comprises a second inductor connected in parallel with the second resonator. wherein 6. A filter comprising: at least one series resonator unit connected in series between an input node and an output node, the series resonator unit comprising a series resonator or comprising a series resonator and an inductor and / or a capacitor connected in parallel or in series with the series resonator; and at least one parallel resonator unit connected in parallel between a connection node and a ground node, the connection node being a node at an input and / or an output of the at least one series resonator unit, the parallel resonator unit comprising a parallel resonator or comprising a parallel resonator and an inductor and / or a capacitor connected in parallel or in series with the parallel resonator, wherein at least one of the at least one series resonator unit and / or the at least one parallel resonator unit is a composite resonator comprising a plurality of resonators; wherein the composite resonator comprises a first resonator, a second resonator, a third resonator, and a fourth resonator, and wherein the first resonator is connected in series with the fourth resonator, the second resonator is connected in parallel with the first resonator and the fourth resonator, and the third resonator is connected in parallel with the fourth resonator.

7. The filter of claim 6, ​ ​ wherein At least one of the first resonator, the second resonator and the third resonator is connected in parallel with an inductor.

8. A filter comprising: at least one series resonator unit connected in series between an input node and an output node, the series resonator unit comprising a series resonator or comprising a series resonator and an inductor and / or a capacitor connected in parallel or in series with the series resonator; and at least one parallel resonator unit connected in parallel between a connection node and a ground node, the connection node being a node at an input and / or output of the at least one series resonator unit, the parallel resonator unit comprising a parallel resonator or comprising a parallel resonator and an inductor and / or a capacitor connected in parallel or in series with the parallel resonator, wherein at least one of the at least one series resonator unit and / or the at least one parallel resonator unit is a composite resonator comprising a plurality of resonators; wherein at least one of the at least one parallel resonator unit is a composite resonator comprising a first resonator, a second resonator, a third resonator and a fourth resonator, wherein the first resonator is connected in series with the fourth resonator and the third resonator is connected in parallel with the fourth resonator, and wherein an input of the second resonator is connected to the connection node to which the composite resonator is connected and an output is connected to any other connection node.

9. The filter according to claim 8, wherein at least one of the first resonator, the second resonator and the third resonator is connected in parallel with an inductor.

10. A multiplexer comprising a filter according to any one of claims 1 to 9.

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