A filter, duplexer, multiplexer, and communication device

Abstract

The application provides a filter, a duplexer, a multiplexer and a communication device. The filter comprises an input terminal, an output terminal, one or more series resonators and one or more parallel resonators, wherein at least one resonator in the one or more series resonators and / or the one or more parallel resonators is split into two series split resonators, and a phase delay factor PDC of the series split resonators satisfies a predetermined range. Through the processing scheme of the present disclosure, the non-linear characteristic of the filter is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, specifically to a filter, a duplexer, a multiplexer, and a communication device. Background Technology

[0002] With the continuous development of mobile communication technology, the trend of spectrum complexity is accelerating. The number of frequency bands used in mobile communication has increased significantly from 4 frequency bands in the early 2000s to more than 50 frequency bands today.

[0003] The increasing complexity of the spectrum makes the requirements for the performance of radio frequency systems more and more stringent. Good radio frequency filter performance can improve the transmission rate, lifespan and reliability of radio frequency systems. Therefore, there is a very urgent need for continuous improvement of filter performance. The continuous improvement of filter performance is mainly reflected in lower insertion loss, higher out-of-band rejection, higher roll-off, higher power capacity and better nonlinear characteristics. Summary of the Invention

[0004] The purpose of this application is to provide a filter, duplexer, multiplexer, and communication device that at least partially solves the problems existing in the prior art.

[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of this disclosure are as follows:

[0006] In a first aspect, embodiments of this disclosure provide a filter, the filter comprising: an input terminal, an output terminal, one or more series resonators, and one or more parallel resonators, wherein...

[0007] The one or more series resonators and / or at least one of the one or more parallel resonators are split in series into two split resonators, wherein the phase delay factor (PDC) of the split resonators satisfies a predetermined range.

[0008] According to a specific implementation of an embodiment of this disclosure, the phase delay factor PDC satisfies: 1.3≤PDC≤4.

[0009] According to a specific implementation of an embodiment of this disclosure, the phase delay factor PDC satisfies: 1.5≤PDC≤3.5.

[0010] According to one specific implementation of the present disclosure, at least one of the first-stage series resonator and the first-stage parallel resonator near the output terminal is split into two series-split resonators.

[0011] According to one specific implementation of this disclosure, the two series-connected split resonators have the same area.

[0012] According to one specific implementation of an embodiment of this disclosure, the two series-connected split resonators have the same shape.

[0013] According to one specific implementation of this disclosure, the area of ​​the two series-connected split resonators is twice the area of ​​the split resonator.

[0014] According to one specific implementation of this disclosure, the average resonant frequency of the two series-split resonators is the same as the resonant frequency of the split resonator.

[0015] According to one specific implementation of this disclosure, the polarization directions of the two series-connected split resonators are opposite.

[0016] According to one specific implementation of this disclosure, the upper electrodes of the two series-split resonators are connected; or the lower electrodes of the two series-split resonators are connected.

[0017] According to one specific implementation of this disclosure, the filter further includes an LC matching circuit at the input terminal and / or the output terminal.

[0018] In a second aspect, a duplexer is provided, the duplexer comprising a filter according to the first aspect of the present disclosure and any implementation thereof.

[0019] Thirdly, a multiplexer is provided, the multiplexer comprising a filter according to the first aspect of this disclosure and any implementation thereof, or a duplexer according to the second aspect of this disclosure.

[0020] Fourthly, a communication device is provided, the communication device comprising a filter according to the first aspect of the present disclosure and any implementation thereof, or a duplexer according to the second aspect of the present disclosure, or a multiplexer according to the third aspect of the present disclosure.

[0021] The filter in this embodiment includes an input terminal, an output terminal, one or more series resonators, and one or more parallel resonators. At least one of the one or more series resonators and / or the one or more parallel resonators is serially split into two series-split resonators, wherein the phase delay factor (PDC) of the series-split resonators satisfies a predetermined range. The processing scheme of this disclosure improves the nonlinear characteristics of the filter. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a design method for improving the nonlinear characteristics of filters in the prior art;

[0024] Figure 2 This is a schematic diagram of the structure of a resonator provided in an embodiment of the present disclosure;

[0025] Figure 3 An electrical symbol and polarization direction diagram of a resonator provided in an embodiment of this disclosure;

[0026] Figure 4 A schematic diagram of a series nonlinear splitting provided in an embodiment of this disclosure;

[0027] Figure 5 A schematic diagram showing the resonant frequency of a resonator provided in an embodiment of this disclosure;

[0028] Figure 6 A schematic diagram of a series nonlinear decomposition with parasitic parameters provided in an embodiment of this disclosure;

[0029] Figure 7 A top view of a resonator provided in an embodiment of this disclosure;

[0030] Figure 8 A graph showing the relationship between the delayed phase θ and the phase delay factor PDC generated at the output terminal of a resonator provided in this embodiment of the disclosure;

[0031] Figure 9 A schematic diagram of the structure of a filter provided in an embodiment of this disclosure;

[0032] Figure 10 This is a comparison graph of the nonlinear frequency response curves of the embodiments of this disclosure and the comparative examples;

[0033] Figure 11 This is a schematic diagram of a duplexer provided in an embodiment of the present disclosure.

[0034] In the figure, 11a, 11b, 11c, 11d - series resonators; 1000 - series split resonator; 12a, 12b, 12c - parallel resonators; 104 - acoustic mirror; 106 - lower electrode; 108 - piezoelectric thin film layer; 110 - upper electrode; 210 - first filter; 220 - second filter. Detailed Implementation

[0035] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0036] The following specific examples illustrate the implementation methods of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] It should be noted that the following description covers various aspects of embodiments within the scope of the appended claims. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0038] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0039] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0040] First, refer to Figure 1 This paper describes the structure of a filter and a design method for improving the nonlinear characteristics of the filter. Figure 1 In the attached diagram, RF is used as the reference numeral. in Indicator input, denoted by RF in the attached diagram. outThe reference numerals 11a, 11b, 11c, and 11d indicate series resonators, and reference numerals SH1, SH2, and SH3 indicate parallel resonators. In other words, this filter includes at least an input terminal, an output terminal, a series resonator, and a parallel resonator.

[0041] In addition, in order to improve the nonlinear characteristics of the filter, such as Figure 1 As shown, it splits one of the resonators into three resonators in series. Specifically, it splits the resonator closer to the output terminal RF into three resonators. out The first series resonator 11d is split into three split resonators 1000. By setting the polarity and signal delay parameters of the split resonators 1000, the second-order nonlinear harmonic components of the split resonators cancel each other out, thereby improving the nonlinear characteristics of the filter.

[0042] In the embodiments of this disclosure, the term "series splitting" refers to splitting a resonator into two or more equivalent resonators connected in series; the term "series nonlinear splitting" refers to splitting a resonator into two or more equivalent resonators connected in series, wherein two adjacent resonators in the two or more resonators after series splitting have opposite polarization directions.

[0043] Figure 1 The design shown splits a single series resonator into three resonators, increasing the resonator area (up to nine times the original area compared to the unsplit case). This is detrimental to miniaturization. Furthermore, parasitic parameters significantly affect the nonlinear characteristics of the filter; the more resonators split, the greater the impact on the nonlinearity. Figure 1 In the scheme shown, the number of resonators split is 3, and the parasitic parameters introduced are more numerous and more complex. This is not conducive to the cancellation of nonlinear harmonic components, thus making it difficult to improve the nonlinear characteristics of the filter.

[0044] In this embodiment of the disclosure, to achieve better nonlinear characteristics of the filter, a resonator is nonlinearly split into two resonators: a first split resonator and a second split resonator. The shape of the resonators is defined, thereby reducing the phase delay of the second-order nonlinear harmonic component generated by the first split resonator transmitted to the output via the second split resonator without further increasing the resonator area. This allows the second-order nonlinear harmonic components generated by the first and second split resonators to cancel each other out to a maximum extent at the signal output, thus improving the nonlinear characteristics of the filter. Hereinafter, with reference to the accompanying drawings, the scheme for improving the nonlinear characteristics of the filter according to an embodiment of the present disclosure will be described in detail.

[0045] First, refer to Figure 2 Describe the structure of the resonators contained in the filter, in Figure 2 middle:

[0046] 106: Lower electrode, the optional material is a metal such as molybdenum, gold, aluminum, magnesium, tungsten, copper, chromium or an alloy of multiple metals.

[0047] 108: Piezoelectric thin film layer, the optional materials are single crystal aluminum nitride, polycrystalline aluminum nitride, zinc oxide, PZT and other materials, and the above piezoelectric materials may contain rare earth elements (such as Sc) doped in a certain atomic ratio.

[0048] 110: Upper electrode, the optional material is a metal such as molybdenum, gold, aluminum, magnesium, tungsten, copper, chromium or an alloy of multiple metals.

[0049] For the resonator, acoustic mirrors are provided on one side of both the upper electrode 110 and the lower electrode 108 in the thickness direction, thereby confining the sound waves inside the piezoelectric resonant cavity. The acoustic mirror can be an air cavity, a Bragg reflector layer, or another material with a significantly different acoustic impedance from the electrode material. The method and form of forming the acoustic mirror are not limited, and the acoustic mirror can also be formed on a substrate supported by other materials. In addition, in the embodiments of this disclosure, the region where the upper electrode 110, the piezoelectric thin film layer 108, the lower electrode 106, and the acoustic mirror overlap and are adjacent to each other in the stacking direction is called the effective resonant region of the resonator.

[0050] Figure 2 The structure of the resonator included in the filter is shown. For a filter, it at least includes, Figure 2 The diagram shows a series resonator and a parallel resonator.

[0051] also, Figure 2 The resonator shown can be simplified as follows: Figure 3 The electrical symbol for the resonator is shown. In Figure 3 In the structure shown, node N1 is connected to the upper electrode 110 of the resonator, and node N2 is connected to the lower electrode 106 of the resonator. Since the half-wavelength of the fundamental resonant frequency of the resonator is approximately equal to the thickness of the piezoelectric thin film layer 108 (i.e., half-wavelength resonance), when the upper electrode 110 is positive, the lower electrode 106 is negative, or vice versa. The polarization direction c of the resonator is defined as pointing from node N2 to node N1 along the thickness direction of the resonator, that is, from the lower electrode 106 to the upper electrode 110 along the thickness direction of the resonator.

[0052] In addition, the wavelength of the second-order nonlinear harmonic is approximately equal to the thickness of the piezoelectric thin film layer 108. That is, when the upper electrode 110 and the lower electrode 106 are positive, the center of the piezoelectric thin film layer 108 is negative, or when the upper electrode 110 and the lower electrode 106 are negative, the center of the piezoelectric thin film layer 108 is positive.

[0053] When the piezoelectric thin film layer 108 is symmetrical in the thickness direction of the resonator, the upper electrode 110 and the lower electrode 106 have the same potential, and no second-order nonlinear harmonics are generated. However, in reality, the piezoelectric thin film layer 108 is not strictly symmetrical in the thickness direction of the resonator. The asymmetry of the piezoelectric thin film layer 108 causes the electric field to be unevenly distributed. This uneven distribution of the electric field causes a second-order nonlinear harmonic potential difference between the upper electrode 110 and the lower electrode 106, thereby generating second-order nonlinear harmonics.

[0054] The term "symmetry" here means that the piezoelectric thin film layer 108 is generally a polycrystalline preferred orientation structure (preferred orientation means that the crystal axes of the material are arranged in the same direction during the preparation process). When the sound wave propagates along the crystal axis direction, the wave speed is the maximum and a stable resonance can be obtained. However, in the actual manufacturing process, the crystal axis is not strictly parallel to the thickness direction, but is slightly tilted, so that the piezoelectric thin film layer 108 is not completely symmetrical in the thickness direction.

[0055] In this embodiment of the disclosure, in order to suppress the generation of second-order nonlinear harmonics, the resonator is serially nonlinearly split, and the shape of the split resonator is defined.

[0056] Figure 4 A schematic diagram of a structure in which the resonator is nonlinearly split in series with the electrodes reversed is shown in an embodiment of this disclosure.

[0057] exist Figure 4 In the example of the series nonlinear split shown, the resonator R is equivalently split into two series-connected resonators, a first resonator R1 and a second resonator R2, wherein the areas and shapes of the first resonator R1 and the second resonator R2 are approximately equal, and the areas of the first resonator R1 and the second resonator R2 are twice the area of ​​the resonator R. Furthermore, the average resonant frequencies of the first resonator R1 and the second resonator R2 are approximately the same as the resonant frequency of the resonator R.

[0058] Furthermore, the polarization direction of the first resonator R1 is opposite to that of the second resonator R2. Figure 4As shown by the solid arrow, the polarization direction c of the first resonator R1 is set opposite to the polarization direction c of the second resonator R2. In this case, the two resonators, the first resonator R1 and the second resonator R2, can be electrically connected through the lower electrode 106. The upper electrode 110 of the first resonator R1 is connected to the signal input terminal in, and the upper electrode 110 of the second resonator R2 is connected to the signal output terminal out.

[0059] It should be understood that the polarization direction c of the first resonator R1 can also be set opposite to the polarization direction c of the second resonator R2 (e.g., Figure 4 (As shown by the dashed arrow in the middle), in this case, the two resonators, the first resonator R1 and the second resonator R2, can be electrically connected through the upper electrode 110, and the lower electrode 106 of the first resonator R1 is connected to the signal input terminal in, and the lower electrode 106 of the second resonator R2 is connected to the signal output terminal out.

[0060] In other words, in this embodiment of the present disclosure, as long as the polarization direction c of the first resonator R1 and the second resonator R2 is opposite when viewed from the signal input terminal in or the signal output terminal out, it is said that the polarization direction c of the first resonator R1 and the polarization direction c of the second resonator R2 are set opposite.

[0061] The above describes the series nonlinear splitting of resonators. However, in practice, since it is impossible to make the areas and shapes of the first resonator R1 and the second resonator R2 exactly equal and twice the area of ​​resonator R, and the average resonant frequencies of the first resonator R1 and the second resonator R2 the same as the resonant frequency of resonator R, it is required that the difference between the areas and shapes of the first resonator R1 and the second resonator R2 is less than a predetermined threshold, and the difference between the area of ​​the first resonator R1 and the second resonator R2 and twice the area of ​​resonator R is less than a predetermined threshold, and the difference between the average resonant frequencies of the first resonator R1 and the second resonator R2 and the resonant frequency of resonator R is less than a predetermined threshold.

[0062] Taking area as an example, assuming the area of ​​the first resonator R1 after series nonlinear splitting is a and the area of ​​the second resonator R2 is b, if the difference between the areas of the two resonators R1 and R2 is required to be less than a predetermined threshold (e.g., 5%), then |ab| / ((a+b) / 2) < 5%. In other words, in the embodiments of this disclosure, equality and approximate equality can be understood as the difference between the two being less than 5%, 3%, or other values.

[0063] In addition, in the above description, "the area of ​​the resonator" refers to the area of ​​the effective resonant region of the resonator, and as mentioned above, the area where the upper electrode 110, the piezoelectric thin film layer 108, the lower electrode 106 and the acoustic mirror overlap and are adjacent to each other in the stacking direction is called the effective resonant region of the resonator.

[0064] In addition, the series nonlinear split requires that the area and shape of the two resonators being split be approximately the same so that the acoustic characteristics of the two resonators are approximately the same. However, in actual manufacturing, due to process deviations, the area and shape of the two resonators cannot be exactly the same. Therefore, the word "approximately" is added in this invention.

[0065] also, Figure 5 The diagram shows the impedance-frequency characteristics of a resonator. The frequency corresponding to the impedance minimum is the series resonant frequency Fs, and the frequency corresponding to the impedance maximum is the parallel resonant frequency Fp. The resonant frequency of a resonator generally refers to its series resonant frequency Fs. The average of the resonant frequencies of the first resonator R1 and the second resonator R2 is the average resonant frequency.

[0066] Continue to refer to Figure 4 H-R1 is the second-order nonlinear harmonic generated by the first resonator R1 at the signal output terminal out, and H-R2 is the second-order nonlinear harmonic generated by the second resonator R2 at the signal output terminal out. Due to the use of... Figure 4 With the electrode reversal setup shown, ideally, the second-order nonlinear harmonics H-R1 and H-R2 have opposite phases and the same amplitude, so they can cancel each other out, thus preventing the generation of second-order nonlinear harmonics at the signal output terminal out.

[0067] However, in reality, such as Figure 6 As shown, an interconnecting metal WL (composed of an upper electrode 110 and / or a lower electrode and / or other metallic materials) exists between the first resonator R1 and the second resonator R2. Therefore, due to the parasitic effects of the interconnecting metal WL and the second resonator R2 itself, the second-order nonlinear harmonic H-R1 generated by the first resonator R1 will experience a certain delay and attenuation after passing through the interconnecting metal WL and the second resonator R2. Figure 6 The second-order nonlinear harmonic H-R1-d shown by the dashed line is the second-order nonlinear harmonic H-R1 generated by the first resonator R1, which is then passed through the interconnecting metal WL and the second resonator R2.

[0068] In other words, the parasitic effects of the interconnecting metal WL and the second resonator R2 itself mean that the second-order nonlinear harmonic H-R2 generated by the second resonator R2 and the second-order nonlinear harmonic H-R1-d generated by the first resonator R1 are not equal in amplitude and opposite in phase at the signal output terminal out. Therefore, the second-order nonlinear harmonics H-R2 and H-R1-d cannot completely cancel each other out. Thus, even if the resonators are nonlinearly split in series, a second-order nonlinear harmonic component H_total will still be generated at the signal output terminal out.

[0069] Furthermore, within a certain delay range, the greater the parasitic effect (including the parasitic effects of the interconnecting metal WL and the second resonator R2 itself), the worse the cancellation effect of the second-order nonlinear harmonics generated by the first resonator R1 and the second resonator R2 at the signal output terminal out, i.e., the worse the nonlinear characteristics. Moreover, at the signal output terminal out, the relationship between the second-order nonlinear harmonic component H_total and the delay phase θ is H_total=α*(1-cosθ), where the second-order nonlinear harmonic component H_total is the harmonic component synthesized from the second-order nonlinear harmonics H-R2 and H-R1-d, and α is the amplitude of the second-order nonlinear harmonic.

[0070] In order to reduce the second-order nonlinear harmonic components caused by parasitic effects, in this embodiment of the disclosure, not only is the resonator serially nonlinearly split, but the shape of the split resonator is also limited, thereby reducing the aforementioned delay phase.

[0071] Figure 7 A top view of the resonator is shown, which includes the effective resonant regions of the two resonators with series nonlinear splitting, and the upper or lower electrodes of the two resonators with series nonlinear splitting. It should be noted that the present invention does not limit the size and relative position of the upper electrode 110, the piezoelectric thin film layer 108, the lower electrode 106, and the acoustic mirror 104.

[0072] exist Figure 7 In the diagram, resonator R is nonlinearly split into a first resonator R1 and a second resonator R2. The closed thick solid line represents the effective resonant region of the resonator, and the dashed line represents the upper or lower electrode of the resonator. The first resonator R1 and the second resonator R2 are interconnected through the upper or lower electrode. The dashed arrow in the diagram indicates the direction of signal propagation. That is, when a two-tone signal is input from the input terminal in to the series nonlinearly split resonator group, both the first resonator R1 and the second resonator R2 generate second-order nonlinear harmonic components. The second-order nonlinear component generated by the first resonator R1 is partially canceled out at the output terminal out by the interconnecting metal WL between the two resonators R1 and R2 and the second resonator R2.

[0073] The following study investigates the relationship between the phase delay factor and the delay phase θ of the second resonator R2. By limiting the phase delay factor of the resonator within a fixed range, the cancellation amount of the second-order nonlinear harmonic components generated by the first resonator R1 and the second resonator R2 at the signal output terminal OUT is increased, thereby further improving the nonlinear characteristics. It should be noted that although the relationship between the phase delay factor and the delay phase θ of the second resonator R2 is used as the research object below, since the first resonator R1 and the second resonator R2 are similar, the corresponding relationship between the phase delay factor and the delay phase θ also applies to the first resonator R1.

[0074] In the embodiments disclosed herein, such as Figure 7 As shown, point X1 is the centroid of the closed shape formed by the effective resonant region of the first resonator R1, and point X2 is the centroid of the closed shape formed by the effective resonant region of the second resonator R2. A straight line passing through points X1 and X2 intersects the closed shape formed by the effective resonant region of the second resonator R2 at points A and B, with a line segment length of 'a' between points A and B. A perpendicular line is drawn from point X2 to the aforementioned straight line, intersecting the closed shape formed by the effective resonant region of the second resonator R2 at points C and D, with a line segment length of 'b' between points C and D. The phase delay factor PDC is defined as b / a. The larger the phase delay factor PDC, the thinner and longer the resonator shape is perpendicular to the signal propagation direction. In this case, the interconnect metal WL is easier to make as short as possible in the signal propagation direction and as long as possible perpendicular to the signal propagation direction, thus reducing the parasitic effects of the interconnect metal WL and the second resonator R2.

[0075] Figure 8 The figure illustrates the relationship between the phase delay factor PDC of the second resonator R2 and the delay phase of the second-order nonlinear harmonic generated by the first resonator R1 at the signal output terminal out. The horizontal axis indicates the phase delay factor PDC, and the vertical axis indicates the delay phase. As can be seen from the figure, as the phase delay factor PDC increases, the delay phase decreases, and when the phase delay factor PDC increases to a certain extent, the delay phase tends to remain constant.

[0076] Specifically, when the phase delay factor PDC = 0.5, the phase delay is 30°; when the phase delay factor PDC = 5, the phase delay is 10°. Furthermore, when the phase delay factor PDC = 1.3, the phase delay is 20°, at which point approximately 6% of the second-order nonlinear harmonics are not canceled; and when the phase delay factor PDC = 4, the phase delay is 15°, at which point approximately 3% of the second-order nonlinear harmonics are not canceled.

[0077] Furthermore, the larger the phase delay factor (PDC), the more elongated the resonator becomes. In this case, the resonator itself is more prone to generating other wave modes. Therefore, in this embodiment, the phase delay factor (PDC) is required to be less than or equal to 4. Preferably, to ensure that uncancelled nonlinear harmonics are less than 6% and that the resonator itself does not excite more parasitic modes, the phase delay factor (PDC) is required to be between 1.3 and 4. More preferably, the phase delay factor (PDC) is required to be between 1.5 and 3.5.

[0078] By limiting the phase delay factor (PDC) of the resonator after series nonlinear splitting, better nonlinear characteristics can be obtained.

[0079] The following description includes, for example Figure 7 The filter circuit of the resonator shown. Figure 9 The diagram shows a circuit topology of a filter according to an embodiment of the present disclosure. The filter is a trapezoidal structure filter and includes series resonators Res1, Res2, Res3 and Res4, and parallel resonators Res5, Res6 and Res7. The series resonator Res4 is equivalently split into two series resonators Res41 and Res42, and the polarization directions of resonators Res41 and Res42 are opposite.

[0080] In addition, T1 is the filter signal input terminal, T2 is the filter signal output terminal, L1 and L2 are the series inductors of the filter signal input terminal T1 and the filter signal output terminal T2, respectively, and L3, L4 and L5 are the series grounding inductors of the parallel branches of the filter, that is, the parallel resonators Res5, Res6 and Res7 are grounded through the series grounding inductors L3, L4 and L5, respectively.

[0081] To achieve better matching, an LC matching circuit can be included at the signal input terminal T1 and / or the signal output terminal T2. Figure 9 The filter structure shown is merely an example. This invention does not limit the number of stages, matching method, or parallel branch grounding method of the trapezoidal filter structure.

[0082] In addition, Figure 9 In the example shown, at least one resonator in the first-stage resonator (including the first series resonator and the first parallel resonator near the signal output terminal T2) undergoes series nonlinear splitting, and the phase delay factor (PDC) of the series-nonlinearly split resonator can be made to meet a specific range, thereby improving the nonlinear characteristics of the filter. Specifically, the first series resonator and / or the first parallel resonator near the signal output terminal T2 can be series-nonlinearly split, and the phase delay factor (PDC) of the series-nonlinearly split resonator is required to meet a specific range. Figure 9In the example shown, the first series resonator Res4 near the signal output terminal T2 is nonlinearly split in series, and the phase delay factor PDC of the split resonator is required to be between 1.3 and 4. More preferably, the phase delay factor PDC is required to be between 1.5 and 3.5. Thus, by splitting at least one of the first-stage series resonator and the first-stage parallel resonator near the output terminal into two split resonators, the nonlinear characteristics of the filter can be further improved.

[0083] Figure 10 The nonlinear frequency response curves of embodiments of this disclosure and comparative examples are shown, where the horizontal axis indicates frequency and the vertical axis indicates the second-order nonlinear harmonic at the output terminal OUT. In the embodiment of this disclosure, the PDC of resonators Res4-1 and Res4-2 is 2.0, while in the comparative example, the PDC of resonators Res4-1 and Res4-2 is 0.8. Figure 10 In the diagram, the line marked with a triangle indicates the second-order nonlinear harmonic of the comparative example (PDC = 0.8 for resonator Res4-2), and the line marked with a circle indicates the second-order nonlinear harmonic of the embodiment of this disclosure (PDC = 2 for resonator Res4-2).

[0084] As shown in the figure, compared with the second-order nonlinear harmonic components generated at the output terminal OUT of resonators Res4-1 and Res4-2 in the comparative example, the second-order nonlinear harmonic components generated at the output terminal OUT of resonators Res4-1 and Res4-2 in the embodiment of this disclosure are smaller. Specifically, the nonlinear harmonic components in the embodiment of this disclosure are on average about 5 dB smaller than those in the comparative example. In other words, compared with the case where the phase delay factor PDC ranges from 1.3 to 4 (the embodiment of this disclosure), when the phase delay factor PDC is not in this range (the comparative example), the cancellation effect of the second-order nonlinear harmonics generated by resonators Res4-1 and Res4-2 is worse. Therefore, in the embodiment of this disclosure, better second-order nonlinear characteristics are achieved by limiting the range of the phase delay factor PDC.

[0085] The above is for reference only. Figure 9 A filter circuit incorporating a resonator according to embodiments of the present disclosure is described, and embodiments of the present disclosure also provide, for example... Figure 11 The duplexer shown has a first filter 210 connected between antenna port Ant and first port T1, and a second filter 220 connected between antenna port Ant and second port T2. The passbands of the first filter 210 and the second filter 220 do not overlap. The first filter 210 can suppress signals of other frequencies while allowing signals of its corresponding passband frequency to pass through, and the second filter 220 can suppress signals of other frequencies while allowing signals of its corresponding passband frequency to pass through.

[0086] Figure 11 The first filter 210 and / or the second filter 220 in the duplexer shown can be Figure 9 The trapezoidal filter shown can also be other types of filters, and these filters include an input terminal, an output terminal, one or more series resonators and one or more parallel resonators, wherein at least one of the one or more series resonators and / or one or more parallel resonators is serially split into two serial split resonators, wherein the phase delay factor PDC of the serial split resonators satisfies a predetermined range.

[0087] The duplexer described in this invention is only an example and is not intended to be limiting. The structure described in this invention can also be applied to multiplexers such as triplets and quadruplets, or to electronic devices that include the above-mentioned filters or multiplexers.

[0088] In addition, this disclosure also provides a communication device, which includes a filter, duplexer, or multiplexer as described above with reference to the accompanying drawings. The specific details of the filter or multiplexer will not be repeated here. The communication device may be an intermediate product such as a radio frequency front-end or a filter amplification module, or a terminal product such as a mobile phone, WIFI, or drone, or a base station product.

[0089] Therefore, the present disclosure provides the following solutions:

[0090] 1. A filter, the filter comprising: an input terminal, an output terminal, one or more series resonators and one or more parallel resonators, wherein...

[0091] The one or more series resonators and / or at least one of the one or more parallel resonators are split in series into two split resonators, wherein the phase delay factor (PDC) of the split resonators satisfies a predetermined range.

[0092] 2. According to the filter described in 1, the phase delay factor PDC satisfies: 1.3≤PDC≤4.

[0093] 3. According to the filter described in 1, the phase delay factor PDC satisfies: 1.5≤PDC≤3.5.

[0094] 4. According to the filter described in 1, at least one of the first-stage series resonator and the first-stage parallel resonator near the output terminal is split in series into two split resonators.

[0095] 5. According to the filter described in 1, the two series-split resonators have the same area.

[0096] 6. According to the filter described in 1, the two series-split resonators have the same shape.

[0097] 7. According to the filter described in 1, the area of ​​the two series-split resonators is twice the area of ​​the split resonator.

[0098] 8. According to the filter described in 1, the average resonant frequency of the two series-split resonators is the same as the resonant frequency of the split resonator.

[0099] 9. According to the filter described in 1, the polarization directions of the two series-split resonators are opposite.

[0100] 10. According to the filter described in 9, the upper electrodes of the two series-split resonators are connected; or the lower electrodes of the two series-split resonators are connected.

[0101] 11. The filter according to claim 1, wherein the filter further comprises an LC matching circuit at the input and / or the output.

[0102] 12. A duplexer comprising a filter according to any one of 1-11.

[0103] 13. A multiplexer comprising a filter according to any one of 1-11 or a duplexer according to 12.

[0104] 14. A communication device comprising a filter according to any one of 1-11, a duplexer according to 12, or a multiplexer according to 13.

[0105] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A filter, characterized in that, The filter includes: an input terminal, an output terminal, one or more series resonators, and one or more parallel resonators. The one or more series resonators and / or at least one of the one or more parallel resonators are series-split into two series-split resonators. The phase delay factor (PDC) of the series-split resonators satisfies a predetermined range. The phase delay factor (PDC) satisfies: 1.3 ≤ PDC ≤ 4. The series-split resonators are a first resonator R1 and a second resonator R2. Point X1 is the centroid of the closed shape formed by the effective resonant region of the first resonator R1, and point X2 is the centroid of the closed shape formed by the effective resonant region of the second resonator R2. A straight line passing through points X1 and X2 intersects the closed shape formed by the effective resonant region of the second resonator R2 at points A and B, with a line segment length of a between points A and B. A perpendicular line is drawn from point X2 to the aforementioned straight line, intersecting the closed shape formed by the effective resonant region of the second resonator R2 at points C and D, with a line segment length of b between points C and D. The phase delay factor (PDC) is b / a.

2. The filter according to claim 1, characterized in that, The phase delay factor PDC satisfies: 1.5≤PDC≤3.

5.

3. The filter according to claim 1, characterized in that, At least one of the first-stage series resonator and the first-stage parallel resonator near the output terminal is split into two series split resonators.

4. The filter according to claim 1, characterized in that, The two series-connected split resonators have the same area.

5. The filter according to claim 1, characterized in that, The two series-split resonators have the same shape.

6. The filter according to claim 1, characterized in that, The area of ​​the two series-connected split resonators is twice the area of ​​the split resonator.

7. The filter according to claim 1, characterized in that, The average resonant frequency of the two series-split resonators is the same as the resonant frequency of the split resonator.

8. The filter according to claim 1, characterized in that, The two series-connected split resonators have opposite polarization directions.

9. The filter according to claim 8, characterized in that, The upper electrodes of the two series-split resonators are connected; or the lower electrodes of the two series-split resonators are connected.

10. The filter according to claim 1, characterized in that, The filter further includes an LC matching circuit at its input and / or output terminals.

11. A duplexer, characterized in that, Includes the filter according to any one of claims 1-10.

12. A multiplexer, characterized in that, Includes the filter according to any one of claims 1-10 or the duplexer according to claim 11.

13. A communication device, characterized in that, It includes the filter according to any one of claims 1-10, the duplexer according to claim 11, or the multiplexer according to claim 12.

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