CN115622529A - Filter and multiplexer including same - Google Patents
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- CN115622529A CN115622529A CN202111361576.7A CN202111361576A CN115622529A CN 115622529 A CN115622529 A CN 115622529A CN 202111361576 A CN202111361576 A CN 202111361576A CN 115622529 A CN115622529 A CN 115622529A
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- H—ELECTRICITY
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- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
- H03H9/542—Filters comprising resonators of piezoelectric or electrostrictive material including passive elements
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/0115—Frequency selective two-port networks comprising only inductors and capacitors
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/0138—Electrical filters or coupling circuits
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/205—Constructional features of resonators consisting of piezoelectric or electrostrictive material having multiple resonators
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
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Abstract
The present disclosure provides a filter and a multiplexer including the filter. The filter according to the present disclosure includes: a main body filtering module; a loading module configured to be connected in series with the body filtering module between an input port and an output port of the filter; and a coupling module configured to be connected between the loading module and the main body filtering module. According to the filter disclosed by the invention, by connecting the loading module and the main filtering module by using the coupling module, an additional coupling path is established between the loading module and the main filtering module, and the suppression of the lower sideband can be enhanced.
Description
Technical Field
The present disclosure relates to the field of electronic circuit technology, and in particular, to a filter and a multiplexer including the filter.
Background
With the development of wireless communication applications, the demand for data transmission rate is higher and higher, and the data transmission rate corresponds to high utilization rate of spectrum resources and complexity of spectrum. The complexity of the communication protocol imposes strict requirements on various performances of the radio frequency system, and the radio frequency filter and the multiplexer play a crucial role in the radio frequency front-end module, and can filter out-of-band interference and noise to meet the requirements of the radio frequency system and the communication protocol on the signal-to-noise ratio. With the increase of 5G commercial products, the demand of multiplexers such as B1, 2, 3, 5, 7, 8 and the like is increasing.
At present, filters and multiplexers based on Film Bulk Acoustic Resonators (FBARs) are increasingly widely used due to their advantages of low insertion loss, steep transition characteristics, high selectivity, high power capacity, and strong anti-electrostatic discharge (ESD) capability.
However, the rapid development of wireless communication technology makes the frequency resources increasingly tense, and the frequency bands allocated to different signals are closer and closer, which brings the problems of mutual interference between signals, system instability and the like, so that the filter is required to have better out-of-band rejection performance to meet the requirement of information transmission. However, prior art ladder filters typically employ an increased number of stages to improve out-of-band rejection performance, however such an approach may introduce more loss and degrade in-band performance.
Therefore, there is still a need in the art for a filter capable of enhancing out-of-band rejection performance and a multiplexer constructed using the filter.
Disclosure of Invention
A brief summary of the disclosure is provided below in order to provide a basic understanding of some aspects of the disclosure. It should be understood, however, that this summary is not an exhaustive overview of the disclosure, nor is it intended to identify key or critical elements of the disclosure, nor is it intended to be used to limit the scope of the disclosure. This summary is provided merely for the purpose of presenting some of the inventive concepts related to the disclosure in a simplified form as a prelude to the more detailed description that is presented later.
An object of the present disclosure is to provide a filter capable of enhancing out-of-band rejection performance and a multiplexer constructed using the filter.
According to an aspect of the present disclosure, there is provided a filter including: a main body filtering module; a loading module configured to be connected in series with the body filtering module between an input port and an output port of the filter; and a coupling module configured to be connected between the loading module and the main body filtering module.
According to an embodiment of the present disclosure, the bulk filtering module has an input node and an output node, and the bulk filtering module includes: at least one series resonator unit connected in series between an input node and an output node of the main body filter module; 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.
According to an embodiment of the present disclosure, each of the at least one series resonator unit includes a series resonator or includes a series resonator and an inductor and/or a capacitor connected in parallel or in series with the series resonator, and each of the at least one parallel resonator unit includes a parallel resonator or includes a parallel resonator and an inductor and/or a capacitor connected in parallel or in series with the parallel resonator.
According to an embodiment of the present disclosure, at least one of the at least one series resonator unit and/or at least one parallel resonator unit comprises two or more resonators connected in parallel and/or in series.
According to the embodiment of the present disclosure, the resonators included in the bulk filter module are all bulk acoustic wave resonators.
According to an embodiment of the present disclosure, the loading module is a high pass circuit of an inductor and a capacitor.
According to an embodiment of the present disclosure, the high-pass circuit includes a T-shaped high-pass circuit, a pi-shaped high-pass circuit, or an L-shaped high-pass circuit.
According to an embodiment of the present disclosure, the loading module includes a first capacitor, a second capacitor, a third capacitor, and a first inductor, one end of the first capacitor is connected to the input port of the filter, the other end is connected to the intermediate node, one end of the second capacitor is connected to the intermediate node, the other end is connected to the input node of the bulk filtering module, and the first inductor and the third capacitor are connected in series between the intermediate node and the ground node.
According to an embodiment of the present disclosure, a body filtering module includes: an input matching inductor connected between the input node and the first connection node; a first parallel resonator unit connected between the first connection node and the ground node, including a first parallel resonator and a first parallel inductor; a first series resonator unit including a first series resonator connected between a first connection node and a second connection node; a second parallel resonator unit connected between the second connection node and the ground node, including a second parallel resonator and a second parallel inductor; a second series resonator unit including a second series resonator connected between the second connection node and a third connection node; a third parallel resonator unit connected between the third connection node and the ground node, including a parallel resonator structure in which two resonators are connected in parallel; a third series resonator unit including a third series resonator connected between a third connection node and a fourth connection node; a fourth parallel resonator unit connected between the fourth connection node and the ground node, including a series resonator structure in which two resonators are connected in series, wherein the third parallel resonator unit and the fourth parallel resonator unit share a third parallel inductor connected to the ground node; a fourth series resonator unit including a fourth series resonator connected in series between the fourth connection node and the fifth connection node; a fifth parallel resonator unit connected between the fifth connection node and the ground node, including a third parallel resonator and a fourth parallel inductor; and an output matching inductor connected between the fifth connection node and the output node.
According to an embodiment of the present disclosure, the coupling module is connected to one connection node.
According to an embodiment of the present disclosure, the coupling module includes an inductive coupling circuit, a capacitive coupling circuit, a transmission line circuit, or a combination thereof.
According to an embodiment of the present disclosure, the transmission line circuit includes a stepped impedance transmission line circuit.
According to an embodiment of the present disclosure, the coupling module includes a second inductor having one end connected to the intermediate node of the loading module and the other end connected to one of the first connection node, the second connection node, and the third connection node of the body filtering module.
According to the embodiment of the disclosure, the coupling module comprises a stepped impedance transmission line composed of a first impedance, a second impedance and a third impedance which are sequentially connected in series, one end of the stepped impedance transmission line is connected to the middle node of the loading module, and the other end of the stepped impedance transmission line is connected to one of the first connection node, the second connection node and the third connection node of the main body filtering module.
According to another aspect of the present disclosure, there is provided a multiplexer including a filter according to the above aspect of the present disclosure.
According to the filter and the multiplexer including the filter of the present disclosure, it may be possible to enhance the out-of-band rejection performance.
Drawings
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated into and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
Fig. 1 shows a schematic diagram of a filter according to an embodiment of the present disclosure.
Fig. 2 shows a circuit diagram of a filter according to an embodiment of the present disclosure.
Fig. 3 shows a circuit diagram of another example of a body filtering module according to an embodiment of the present disclosure.
Fig. 4A to 4C show circuit diagrams of other examples of a load module according to an embodiment of the present disclosure.
Fig. 5A and 5B show frequency response graphs of filters without the coupling module and with the coupling module shown in fig. 2.
Fig. 6 shows a circuit diagram of another example of a coupling module according to an embodiment of the present disclosure.
Fig. 7A and 7B show frequency response graphs of filters without the coupling module and with the coupling module shown in fig. 6.
Detailed Description
In this specification, it will also be understood that when an element is referred to as being "on," "connected to," or "coupled to" other elements relative to the other elements, such as on, "connected to," or "coupled to" the other elements, the one element may be directly on, connected or coupled to the one element, or an intervening third element may also be present. In contrast, when an element is referred to in this specification as being "directly on," "directly connected to," or "directly coupled to" other elements, relative to the other elements, there are no intervening elements provided therebetween.
The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like numbers refer to like elements throughout. Also, in the drawings, the thickness, ratio and size of the components are exaggerated for clarity of illustration.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, "a," "an," "the," and "at least one" do not denote a limitation of quantity, but rather are intended to include both the singular and the plural, unless the context clearly dictates otherwise. For example, "an element" means the same as "at least one element" unless the context clearly dictates otherwise. "at least one of" should not be construed as limited to the quantity "one". "or" means "and/or". The term "and/or" includes any and all combinations of one or more of the associated listed items.
Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms defined in commonly used dictionaries should be interpreted as having the same meaning as is in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The meaning of "comprising" or "comprises" indicates a property, a quantity, a step, an operation, an element, a component or a combination thereof, but does not exclude other properties, quantities, steps, operations, elements, components or combinations thereof.
Embodiments are described herein with reference to cross-sectional views that are idealized embodiments. Thus, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region shown or described as flat may typically have rough and/or nonlinear features. Also, the acute angles shown may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the claims.
Hereinafter, exemplary embodiments according to the present disclosure will be described with reference to the accompanying drawings.
Fig. 1 shows a schematic diagram of a filter 100 according to an embodiment of the present disclosure. Fig. 2 shows a circuit diagram of a filter 100 according to an embodiment of the present disclosure.
According to an embodiment of the present disclosure, as shown in fig. 1, the filter 100 includes: a main body filtering module 101; a loading module 102 connected IN series with the main body filtering module 101 between the input port IN and the output port OUT of the filter 100; and a coupling module 103 connected between the loading module 102 and the main body filtering module 101.
Although IN fig. 1, the loading module 102 is shown as being connected between the input port IN and the bulk filtering module 101, the present disclosure is not limited thereto. According to another embodiment of the present disclosure, the loading module 102 may also be connected between the body filtering module 101 and the output port OUT.
According to an embodiment of the present disclosure, the loading module 102 may function as a high-pass filter, thereby enhancing the out-of-band rejection performance.
As shown in fig. 2, according to an embodiment of the present disclosure, the body filtering module 101 may have an input node N10 and an output node N16, and the body filtering module 101 may include: at least one series resonator unit connected in series between an input node N10 and an output node N16; and at least one parallel resonator unit connected in parallel between connection nodes N11 to N15 and a ground node GND, the connection nodes N11 to N15 being nodes at an input terminal and/or an output terminal of the at least one series resonator unit.
Specifically, as shown in fig. 2, the body filter module 101 may include first to fourth series resonator units connected in series between an input node N10 and an output node N16, wherein the first series resonator unit includes a resonator X11 connected in series between a first connection node N11 and a second connection node N12, the second series resonator unit includes a resonator X12 connected in series between the second connection node N12 and a third connection node N13, the third series resonator unit includes a resonator X13 connected in series between the third connection node N13 and a fourth connection node N14, and the fourth series resonator unit includes a resonator X14 connected in series between the fourth connection node N14 and a fifth connection node N15.
Further, as shown in fig. 2, the body filter module 101 may include first to fifth parallel resonator units connected in parallel between connection nodes N11 to N15 and a ground node GND, wherein the first parallel resonator unit is connected between the first connection node N11 and the ground node GND and includes a resonator Y11 and an inductor L11, the second parallel resonator unit is connected between the second connection node N12 and the ground node GND and includes a resonator Y12 and an inductor L12, the third parallel resonator unit is connected between the third connection node N13 and the ground node GND and includes a resonator Y13 and an inductor L13, the fourth parallel resonator unit is connected between the fourth connection node N14 and the ground node GND and includes a resonator Y14 and an inductor L14, and the fifth parallel resonator unit is connected between the fifth connection node N15 and the ground node GND and includes a resonator Y15 and an inductor L15.
In addition, the body filtering module 101 may include an input matching inductor LIN connected between the input node N10 and the first connection node N11 and an output matching inductor LOUT connected between the fifth connection node N15 and the output node N16. Inductors LIN and LOUT may be used to adjust the input and output phases of the bulk filtering module 101 to make its passband more flat.
According to the embodiment of the present disclosure, the main body filter module 101 may have a ladder filter structure, have a low insertion loss, and may support a steep filter curve in a high frequency band. The lower insertion loss can bring longer endurance, which is beneficial to maximization of input signal strength and brings higher data throughput, the steep filtering curve can bring better coexistence of adjacent frequency bands, and the better out-of-band rejection capability can bring more frequency band working capabilities.
Further, according to the embodiment of the present disclosure, each of the resonators X11 to X14 and Y11 to Y15 included in the body filter module 101 may be a bulk acoustic wave resonator. The working principle of the bulk acoustic wave resonator is as follows: when an electric signal is applied, the piezoelectric film in the bulk acoustic wave resonator converts the electric signal into an acoustic signal through an inverse transformation effect, and a specific acoustic structure in the bulk acoustic wave resonator presents selectivity to acoustic signals with different frequencies, wherein the acoustic signal meeting the acoustic wave total reflection condition in the bulk acoustic wave resonator realizes resonance in the bulk acoustic wave resonator, while the acoustic signal not meeting the resonance condition is attenuated, and the acoustic signal with more frequency difference with the resonant acoustic signal on a frequency spectrum is more quickly attenuated. Finally, the acoustic signal with the difference in amplitude and phase in the bulk acoustic wave resonator is converted into an output electric signal in equal proportion through the piezoelectric film. At present, a Film Bulk Acoustic Resonator (FBAR) based on the MEMS technology has the advantages of high frequency, small volume, high transduction efficiency, and the like. High-performance small-volume radio frequency devices such as filters, duplexers and multiplexers manufactured by using FBARs have become key technologies for solving the miniaturization and low power consumption of communication systems.
Further, according to an embodiment of the present disclosure, each of the series resonator units may also include a series resonator and an inductor and/or a capacitor connected in parallel or in series with the series resonator. Further, according to an embodiment of the present disclosure, each of the parallel resonator units may also include a parallel resonator and an inductor and/or a capacitor connected in parallel or in series with the parallel resonator.
Furthermore, those skilled in the art will recognize that although the bulk filter module 101 shown in fig. 2 has four series resonator units and five parallel resonator units, the present disclosure is not limited thereto. Those skilled in the art may use other numbers of series resonator elements and parallel resonator elements depending on the specific application and design requirements, and all such variations are intended to be within the scope of the present disclosure.
Furthermore, those skilled in the art will recognize that the series resonator units and parallel resonator units included in the bulk filtering module 101 are not limited to the circuit topology shown in fig. 2. According to an embodiment of the present disclosure, at least one of the at least one series resonator unit and/or at least one parallel resonator unit comprises two or more resonators connected in parallel and/or in series.
Fig. 3 shows a circuit diagram of another example of the body filtering module 101 according to an embodiment of the present disclosure. For the sake of brevity, the same elements as those shown in fig. 2 in fig. 3 are denoted by the same reference numerals, and repetitive description thereof is omitted.
As shown in fig. 3, the third parallel resonator unit may be implemented by a structure of two resonators Y131 and Y132 connected in parallel, the fourth parallel resonator unit may be implemented by a structure of two resonators Y141 and Y142 connected in series, and the third parallel resonator unit and the fourth parallel resonator unit share one inductor L134 and are grounded.
According to the embodiment of the present disclosure, by implementing the parallel resonator unit using the parallel resonator structure or the series resonator structure, the rf signals can pass through the upper and lower electrodes of the two resonators connected in parallel or in series, respectively, and the generated nonlinear components have the same amplitude and opposite phases, and thus can cancel each other out. Therefore, the layout area utilization rate of the whole main body filtering module 101 can be improved, the electrode loss and the parasitic effect are reduced, and the nonlinear suppression capability is enhanced.
Although it is shown in fig. 3 that the third and fourth parallel resonator units are implemented by a parallel resonator structure and a series resonator structure, respectively, the present disclosure is not limited thereto, and other parallel resonator units may be implemented using a parallel resonator structure and/or a series resonator structure, and furthermore, any of the first to fourth series resonator units may be implemented using a parallel resonator structure and/or a series resonator structure. In fact, any of the parallel resonator units and the series resonator units may also be implemented in a manner that the parallel resonator structure is connected in series and/or in parallel with the series resonator structure, according to embodiments of the present disclosure. That is, any of the parallel resonator units and the series resonator units may be implemented by any combination of the parallel resonator structures and/or the series resonator structures. All such variations are intended to be within the scope of the present disclosure.
Further, although fig. 3 illustrates the use of a parallel resonator structure and a series resonator structure including two resonators, the present disclosure is not limited thereto. According to the embodiments of the present disclosure, a greater number (more than two) of resonators may be used to constitute the parallel resonator structure and the series resonator structure. Further, according to the embodiments of the present disclosure, the number of resonators constituting the parallel resonator structure may be the same as or different from the number of resonators constituting the series resonator structure.
According to an embodiment of the present disclosure, the loading module 102 may be a high-pass circuit composed of an inductor and a capacitor. For example, as shown in fig. 2, the loading module 102 may be a T-shaped high-pass circuit formed by an inductor L2 and capacitors C1 to C3. According to an embodiment of the present disclosure, the loading module 102 may enhance rejection of the low frequency band of the filter 100.
Specifically, as shown IN fig. 2, the loading module 102 may include capacitors C1 to C3 and an inductor L2, one end of the capacitor C1 is connected to the input port IN of the filter 100, the other end is connected to the intermediate node N2, one end of the capacitor C2 is connected to the intermediate node N2, the other end is connected to the input node N10 of the bulk filtering module 101, and the inductor L2 and the capacitor C3 are connected IN series between the intermediate node N2 and the ground node GND.
Further, although it is shown IN fig. 2 that the input terminal of the loading module 102 is connected to the input port IN of the filter 100 and the output terminal is connected to the input node N10 of the bulk filtering module 101, as described above, the present disclosure is not limited thereto. According to an embodiment of the present disclosure, the input of the loading module 102 may also be connected to the output node N16 of the body filtering module 101, and the output is connected to the output port OUT of the filter 100.
Furthermore, the circuit topology of the load module 102 is not limited to the example shown in FIG. 2. Fig. 4A-4C illustrate circuit diagrams of other examples of the load module 102 according to embodiments of the present disclosure. For the sake of brevity, the same elements as those shown in fig. 2 in fig. 4A to 4C are denoted by the same reference numerals, and repetitive descriptions thereof are omitted. According to an embodiment of the present disclosure, as shown in fig. 4A, the loading module 102 may be a pi-shaped high-pass circuit composed of a capacitor C1 and inductors L21 and L22. Further, according to the embodiment of the present disclosure, as shown in fig. 4B, the loading module 102 may be a pi-shaped high-pass circuit composed of the capacitor C1 and the inductors L21 to L23. Further, according to the embodiment of the present disclosure, as shown in fig. 4C, the loading module 102 may be an L-shaped high-pass circuit formed by a capacitor C1 and an inductor L2.
As shown in fig. 2, the coupling module 103 may be an inductive coupling circuit. According to the embodiment of the present disclosure, when the coupling module 103 is formed of an inductive coupling circuit, the suppression capability of the lower sideband of the filter 100 can be enhanced.
Specifically, as shown in fig. 2, the coupling module 103 may include an inductor L3, one end of the inductor L3 being connected to the intermediate node N2 of the loading module 102, and the other end being connected to the first connection node N11 of the body filtering module 101.
Body filtering module although it is illustrated in fig. 2 that one end of the coupling module 103 is connected to the intermediate node N2 of the loading module 102 and the other end is connected to the first connection node N11 in the body filtering module 101, the present disclosure is not limited thereto. According to an embodiment of the present disclosure, the other end of the coupling module 103 may be connected to one of the first connection node N11, the second connection node N12, and the third connection node N13 of the body filtering module 101. Further, according to an embodiment of the present disclosure, the other end of the coupling module 103 may be connected to any one of the first to fifth connection nodes N11 to N15 in the body filtering module 101.
When the other end of the coupling module 103 is connected to a different one of the first to fifth connection nodes N11 to N15 in the body filtering module 101, the effect of lower sideband suppression achieved is different.
Fig. 5A and 5B show frequency response plots of the filter 100 without the coupling module 103 and with the coupling module 103 shown in fig. 2. Fig. 5A and 5B show frequency response curves of the filter 100 in a case where the coupling module 103 is not used (solid line), in a case where the other end of the coupling module 103 is connected to the first connection node N11 (short dashed line), in a case where the other end of the coupling module 103 is connected to the second connection node N12 (middle dashed line), and in a case where the other end of the coupling module 103 is connected to the third connection node N13 (long dashed line), respectively.
As shown in fig. 5A and 5B, when the coupling module 103 performs inductive coupling of the first connection node N11, the second connection node N12, and the third connection node N13 of the bulk filtering module 101 and the loading module 102, respectively, suppression enhancement of the lower sideband is generated, wherein when the coupling module 103 is connected to the third connection node N3, the suppression effect on the lower sideband is strongest, and the suppression peak reaches over 80dB, but the suppression at a frequency lower than 3GHz is inferior to that of the first connection node N11 and the second connection node N12. In addition, for three cases that the coupling module 103 is connected to the first connection node N11, the second connection node N12, and the third connection node N13 of the main body filter module 101, respectively, the return loss is not much different, and the pass band insertion loss thereof reaches a level of 17dB or more.
Therefore, according to the embodiment of the present disclosure, by introducing the coupling module 103 between the main body filtering module 101 and the loading module 102, the suppression capability of the lower sideband can be enhanced.
Although fig. 2 illustrates a case where the coupling module 103 is implemented by an inductive coupling circuit, the present disclosure is not limited thereto. According to embodiments of the present disclosure, the coupling module 103 may include an inductive coupling circuit, a capacitive coupling circuit, a transmission line circuit, or a combination thereof.
Fig. 6 shows a circuit diagram of another example of a coupling module 103 according to an embodiment of the present disclosure. For the sake of brevity, the same elements in fig. 6 as those shown in fig. 3 are denoted by the same reference numerals, and repetitive description thereof is omitted.
According to an embodiment of the present disclosure, as shown in fig. 6, the coupling module 103 may be a stepped impedance transmission line circuit composed of impedances Z1, Z2, and Z3 connected in series. Further, in fig. 6, the coupling module 103 includes a stepped impedance transmission line circuit connected between the node N2 of the loading module 102 and the third connection node N13 of the main body filtering module 101.
According to the embodiment of the present disclosure, the step impedance transmission line circuit for implementing the coupling module 103 is formed by cascading at least two sections of transmission lines with different impedances, the transmission line circuit has a broadband filtering characteristic, and a broadband coupling effect can be implemented by using the step impedance transmission line circuit instead of the inductive coupling circuit. Generally, the impedance value of the stepped impedance transmission line circuit is 20 to 150 ohms.
Fig. 7A and 7B show frequency response graphs of filters without the coupling module 103 and with the coupling module 103 shown in fig. 6. Fig. 7A and 7B show frequency response curves of the filter 100 in the case where the coupling module 103 is not used (solid line) and in the case where the other end of the coupling module 103 shown in fig. 6 is connected to the third connection node N13 (short dashed line), respectively.
As shown in fig. 7A and 7B, since the coupling module 103 of fig. 6 is formed of a stepped-impedance transmission line circuit, it has a broadband effect, is suitable for high-frequency suppression, and has a better high-frequency suppression capability than the case where the coupling module 103 is not used. In particular, as shown in fig. 7A and 7B, it can be seen that the circuit simulation results after adding the coupling module 103 of fig. 6 composed of a stepped impedance transmission line have a significantly enhanced signal rejection at 6-8GHz, with the lower sideband rejection, the lower frequency rejection, and the upper sideband rejection unchanged.
Furthermore, according to an embodiment of the present disclosure, there is also provided a multiplexer including the filter according to the above embodiment of the present disclosure.
According to the technical scheme of the disclosure, the filter can be composed of three modules, namely a main body filtering module, a loading module and a coupling module, wherein the main body filtering module and the loading module can establish electrical association through the coupling module. The devices constituting the coupling module include, but are not limited to, inductors, capacitors, transmission lines, etc., and by adjusting the parameter values of these devices, different functions can be realized, and corresponding technical effects can be obtained. In particular, where the coupling module uses inductive coupling, different effects may be produced by connecting the coupling module to different connection nodes (e.g., N11, N12, or N13) of the body filtering module, but both enhance the lower sideband suppression capability. Furthermore, when the coupling module uses a stepped impedance transmission line, a positive effect on high frequency rejection may be achieved. Further, by implementing the resonator unit constituting the bulk filter module using the parallel resonator structure and/or the series resonator structure, it is possible to reduce electrode loss and parasitic effect and enhance the nonlinear suppression capability.
Although the present disclosure has been described with reference to exemplary embodiments thereof, those skilled in the art will appreciate that various modifications and changes may be made without departing from the spirit and scope of the present disclosure as set forth in the claims.
Claims (15)
1. A filter, comprising:
a main body filtering module;
a loading module configured to be connected in series with the body filtering module between an input port and an output port of the filter; and
a coupling module configured to be connected between the loading module and the bulk filtering module.
2. The filter of claim 1, wherein the bulk filtering module has an input node and an output node, and the bulk filtering module comprises:
at least one series resonator unit connected in series between an input node and an output node of the body filter module; and
at least one parallel resonator cell 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 cell.
3. The filter of claim 2, wherein,
each of the at least one series resonator unit comprises a series resonator or a series resonator and an inductor and/or a capacitor connected in parallel or in series with the series resonator, and
each of the at least one parallel resonator unit includes a parallel resonator or a parallel resonator and an inductor and/or a capacitor connected in parallel or in series with the parallel resonator.
4. The filter of claim 3,
at least one of the at least one series resonator unit and/or the at least one parallel resonator unit comprises two or more resonators connected in parallel and/or in series.
5. The filter of claim 1, wherein the resonators included in the bulk filter module are all bulk acoustic wave resonators.
6. The filter of claim 1, wherein the loading module is a high pass circuit of inductors and capacitors.
7. The filter of claim 6, wherein the high pass circuit comprises a T-shaped high pass circuit, a pi-shaped high pass circuit, or an L-shaped high pass circuit.
8. The filter according to claim 2, wherein the filter is a linear filter,
wherein the loading module comprises a first capacitor, a second capacitor, a third capacitor, and a first inductor,
wherein one end of the first capacitor is connected to an input port of the filter and the other end is connected to an intermediate node,
one end of the second capacitor is connected to the intermediate node and the other end is connected to an input node of the bulk filtering module, an
Wherein the first inductor and the third capacitor are connected in series between the intermediate node and the ground node.
9. The filter according to claim 8, wherein the filter is a linear filter,
wherein the main body filtering module includes:
an input matching inductor connected between the input node and a first connection node;
a first parallel resonator unit connected between the first connection node and the ground node, including a first parallel resonator and a first parallel inductor;
a first series resonator unit including a first series resonator connected between the first connection node and a second connection node;
a second parallel resonator unit connected between the second connection node and the ground node, including a second parallel resonator and a second parallel inductor;
a second series resonator unit including a second series resonator connected between the second connection node and a third connection node;
a third parallel resonator unit connected between the third connection node and the ground node, including a parallel resonator structure in which two resonators are connected in parallel;
a third series resonator unit including a third series resonator connected between the third connection node and a fourth connection node;
a fourth parallel resonator unit connected between the fourth connection node and the ground node, comprising a series resonator structure in which two resonators are connected in series, wherein the third and fourth parallel resonator units share a third parallel inductor connected to the ground node;
a fourth series resonator unit including a fourth series resonator connected in series between the fourth connection node and a fifth connection node;
a fifth parallel resonator unit connected between the fifth connection node and the ground node, including a third parallel resonator and a fourth parallel inductor; and
an output matching inductor connected between the fifth connection node and the output node.
10. A filter according to claim 2, wherein the coupling module is connected to one of the connection nodes.
11. The filter of claim 1, wherein the coupling module comprises an inductive coupling circuit, a capacitive coupling circuit, a transmission line circuit, or a combination thereof.
12. The filter of claim 11, wherein the transmission line circuit comprises a stepped impedance transmission line circuit.
13. The filter of claim 8, wherein the coupling module includes a second inductor having one end connected to the intermediate node of the loading module and another end connected to one of the first, second, and third connection nodes of the bulk filtering module.
14. The filter of claim 8, wherein the coupling module comprises a stepped impedance transmission line of a first impedance, a second impedance and a third impedance connected in series in that order, the stepped impedance transmission line having one end connected to the intermediate node of the loading module and the other end connected to one of the first connection node, the second connection node and the third connection node of the bulk filtering module.
15. A multiplexer comprising a filter according to any one of claims 1 to 14.
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| CN202111361576.7A CN115622529A (en) | 2021-11-17 | 2021-11-17 | Filter and multiplexer including same |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115955212A (en) * | 2023-03-14 | 2023-04-11 | 阿尔伯达(苏州)科技有限公司 | SAW filter with enlarged bandwidth |
| CN117254780A (en) * | 2023-10-11 | 2023-12-19 | 山东大学 | Parting filter and working method |
-
2021
- 2021-11-17 CN CN202111361576.7A patent/CN115622529A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115955212A (en) * | 2023-03-14 | 2023-04-11 | 阿尔伯达(苏州)科技有限公司 | SAW filter with enlarged bandwidth |
| CN117254780A (en) * | 2023-10-11 | 2023-12-19 | 山东大学 | Parting filter and working method |
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