Filter, multiplexer and radio frequency front-end module

Abstract

The invention discloses a filter, a multiplexer and a radio frequency front end module, the filter comprises a first port, a second port, M first resonators, N second resonators and a third resonator, and the filter filters a radio frequency signal transmitted from the second port to the first port; the M first resonators are connected in series between the first port and the second port; the first ends of the second resonators are connected between two adjacent first resonators; in the first direction, the second end of the first second resonator is connected with the first node, and the second end of at least one second resonator from the second resonator to the Nth resonator is connected with the second node; the first node is grounded, and the second node is grounded through the first inductor; the first end of the third resonator is connected between the first first resonator and the second first resonator in the first direction, and the second end of the third resonator is connected with the second node; the first direction is a direction from the first port to the second port. According to the embodiment of the invention, the nonlinear problem of the filter can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency filtering, and in particular relates to a filter, a multiplexer and a radio frequency front-end module. Background Art

[0002] Surface Acoustic Wave (SAW) filter is a widely used filter in RF front-end. Its basic structure includes a piezoelectric substrate and an interdigital transducer (IDT) on the piezoelectric substrate. The working principle of SAW filter is based on the piezoelectric effect and inverse piezoelectric effect of piezoelectric materials.

[0003] In practical applications, SAW filters will have nonlinear phenomena due to the influence of factors such as material properties, device structure or external excitation. The nonlinear phenomenon is manifested as the non-linear relationship between the input signal and the output signal, which may cause problems such as signal distortion and intermodulation interference, seriously affecting the performance and stability of the filter. Especially in the case of high power input, the nonlinearity is particularly obvious and may even cause the filter to fail to work properly. Summary of the invention

[0004] The present application provides a filter, a multiplexer and a radio frequency front-end module, aiming to improve the nonlinear problem of the SAW filter.

[0005] In a first aspect, the present application provides a filter, comprising:

[0006] a first port and a second port, the filter being used to filter the radio frequency signal transmitted from the second port to the first port;

[0007] M first resonators, the M first resonators are connected in series between the first port and the second port, wherein M is a positive integer greater than or equal to 2;

[0008] N second resonators, the first end of the second resonator is connected between two adjacent first resonators; in the first direction, the second end of the first second resonator is connected to the first node, and the second end of at least one second resonator from the second to the Nth second resonator is connected to the second node; wherein the first node is used for grounding, and the second node is used for grounding through the first inductor;

[0009] a third resonator, wherein a first end of the third resonator is connected between the first first resonator and the second first resonator in the first direction, and a second end of the third resonator is connected to the second node;

[0010] The first direction is the direction from the first port to the second port.

[0011] According to the filter provided in the first aspect of the present application, the second resonator 12 and the third resonator 13 are connected in parallel between the first two first resonators 11 close to the RF signal output side, and the second resonator 12 and the third resonator 13 are connected to different nodes and can resonate with different inductors to produce different zero points, so that the nonlinear signal generated by the previous resonator can be suppressed on the output side of the filter 10, thereby improving the linearity of the filter 10. In addition, due to the increase in zero points, the filter 10 can improve its ability to suppress out-of-band noise, which can improve out-of-band suppression while improving nonlinear problems.

[0012] In a second aspect, the present application provides a filter, comprising:

[0013] a first port and a second port, the filter being used to filter the radio frequency signal transmitted from the second port to the first port;

[0014] M first resonators, the M first resonators are connected in series between the first port and the second port, wherein M is a positive integer greater than or equal to 2;

[0015] N second resonators, wherein a first end of the second resonator is connected between two adjacent first resonators, in a first direction, a second end of at least the kth second resonator is connected to the first node, and a second end of at least one other second resonator is connected to the second node, wherein the first node is used for grounding, and the second node is used for grounding through a first inductor;

[0016] A third resonator, wherein a first end of the third resonator is connected between the kth first resonator and the k+1th first resonator in the first direction, and a second end of the third resonator is connected to the second node;

[0017] Wherein, k is a positive integer and 1≤k≤N, and the first direction is a direction from the first port to the second port.

[0018] According to the filter provided in the second aspect of the present application, a third resonator 13 is added in parallel between two adjacent first resonators connected in series, thereby increasing the depth of the out-of-band zero point on the frequency response curve of the filter 10, thereby improving the filter 10's ability to suppress out-of-band noise.

[0019] In a third aspect, the present application provides a filter, comprising:

[0020] a first port and a second port, the filter being used to filter the radio frequency signal transmitted from the second port to the first port;

[0021] M first resonators, the M first resonators are connected in series between the first port and the second port, wherein M is a positive integer greater than or equal to 2;

[0022] N second resonators, the second resonators are connected between two adjacent first resonators; in the first direction, the second end of the first second resonator is connected to the first node; in the second to N second resonators, the first node is connected to the second end of at least one second resonator, and the second node is connected to the second ends of multiple different second resonators; the first node and the second node are both used for grounding;

[0023] A third resonator, wherein a first end of the third resonator is connected between the first first resonator and the second first resonator in the first direction, and a second end of the third resonator is connected to the second node;

[0024] Among them, the first direction is the direction from the first port to the second port; the capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node; and the corresponding capacitance value is the capacitance value of the static capacitance of the resonator connected to the node.

[0025] According to the filter provided in the third aspect of the present application, by introducing multiple parallel second resonators 12 between multiple first resonators 11 connected in series, and connecting their second ends to different ground nodes, the number of out-of-band zeros of the filter can be increased, thereby improving the out-of-band suppression level of the filter 10. By setting the capacitance value corresponding to the second node to be greater than the capacitance value corresponding to the first node, the difference between the zero frequency corresponding to the first node and the zero frequency corresponding to the second node can be increased, so that the frequency range covered between the two zeros is wider, further improving the suppression effect of out-of-band signals. Furthermore, the design of the filter 10 effectively improves out-of-band suppression and nonlinear problems by adjusting the number and connection method of the resonators.

[0026] In a fourth aspect, the present application provides a multiplexer, the multiplexer comprising at least two filters, at least one of the at least two filters being a filter as described in any one of the first aspect above, or a filter as described in any one of the second aspect above, or a filter as described in any one of the third aspect above.

[0027] In a fifth aspect, the present application provides a radio frequency front-end module, the radio frequency front-end module comprising: a filter as described in any one of the first aspects above, or a filter as described in any one of the second aspects above, or a filter as described in any one of the third aspects above.

[0028] The present application aims to effectively improve the nonlinear problem of SAW filters by improving the structural design of traditional SAW filters. By connecting the second resonator and the third resonator in parallel between the first resonator in series, and setting at least two nodes to access different inductors, the multi-stage resonator can produce at least two zero points with different inductors, which can effectively suppress the nonlinear effects caused by high-power input signals, thereby helping to reduce signal distortion and intermodulation interference and improve the linearity of the filter. The parallel design of the second resonator and the third resonator can enhance the attenuation ability of the filter at out-of-band frequencies. At the same time, the above design further improves the effect of out-of-band suppression.

[0029] In summary, the present application effectively solves the deficiencies of traditional SAW filters in terms of nonlinearity and out-of-band suppression through an improved structural design of the filter, improves the linearity and out-of-band suppression capability of the filter, thereby significantly improving the performance and reliability of the multiplexer and RF front-end module in which the filter is used.

[0030] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 It is a structural schematic block diagram of the first filter provided by an embodiment of the present application;

[0033] Figure 2 is a schematic diagram of the zero frequency of the filter provided in one embodiment of the present application;

[0034] Figure 3 It is a structural schematic block diagram of the second filter provided in an embodiment of the present application;

[0035] Figure 4 It is a structural schematic block diagram of the third filter provided in an embodiment of the present application;

[0036] Figure 5 It is a structural schematic block diagram of the fourth filter provided in an embodiment of the present application;

[0037] Figure 6 It is a structural schematic block diagram of the fifth filter provided in an embodiment of the present application;

[0038] Figure 7It is a structural schematic block diagram of the sixth filter provided in an embodiment of the present application;

[0039] Figure 8 It is a structural schematic block diagram of the seventh filter provided in an embodiment of the present application;

[0040] Fig. 9 It is a schematic block diagram of the structure of the eighth filter provided in an embodiment of the present application;

[0041] Fig.10 It is a structural schematic block diagram of the ninth filter provided by an embodiment of the present application;

[0042] Fig.11 is a schematic diagram of a multiplexer provided in an embodiment of the present application;

[0043] Fig.12 is a schematic diagram of a radio frequency front-end module provided in an embodiment of the present application;

[0044] Fig.13 It is a schematic diagram of the test results of the comparative example;

[0045] Fig.14 It is a schematic diagram of test results of an embodiment of the present application.

[0046] Description of reference numerals:

[0047] 10. Filter;

[0048] 11, first resonator; 12, second resonator; 13, third resonator; 14, fourth resonator; 15, fifth resonator; L0, first inductor; L1, second inductor;

[0049] 20. Multiplexer;

[0050] 30. RF front-end module.

[0051] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0053] It should be understood that the present application can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present application to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0054] In order to thoroughly understand the present application, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by the present application. The preferred embodiments of the present application are described in detail below, but in addition to these detailed descriptions, the present application may also have other implementation methods.

[0055] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0056] To solve the nonlinearity and out-of-band suppression problems of SAW filters. Figure 1 An embodiment of the present application provides a filter 10 including a first port, a second port, M first resonators 11 , N second resonators 12 and a third resonator 13 .

[0057] The filter 10 is used to filter the radio frequency signal transmitted from the second port to the first port. M first resonators 11 are connected in series between the first port and the second port, wherein M is a positive integer greater than or equal to 2. The first end of the second resonator 12 is connected between two adjacent first resonators 11; in the first direction, the second end of the first second resonator 12 is connected to the first node, and the second end of at least one second resonator 12 from the second to the Nth second resonator 12 is connected to the second node; wherein the first node is used for grounding, and the second node is used for grounding through the first inductor L0. The first end of the third resonator 13 is connected between the first first resonator 11 and the second first resonator 11 in the first direction, and the second end of the third resonator 13 is connected to the second node. wherein the first direction is the direction from the first port to the second port, that is, the first second resonator 12 in the first direction is the resonator connected to the first port, and the first second resonator 12 in the first direction is the second resonator connected between the first two first resonators.

[0058] Specifically, the filter 10 provided in the present application forms a multi-stage resonator by introducing a plurality of resonator structures connected in series and in parallel, thereby filtering out a specific frequency in the signal or a signal other than a specific frequency. By setting a plurality of nodes to access different inductors, the multi-stage resonator can generate a plurality of zero points with different inductors, thereby improving the suppression of out-of-band noise. On this basis, the filter 10 adds a third resonator 13 in parallel between the first first resonator 11 and the second first resonator 11 in the first direction, that is, a second resonator 12 and a third resonator 13 are connected in parallel between the first two first resonators 11 close to the output side of the RF signal, and the second resonator 12 and the third resonator 13 are connected to different nodes and can resonate with different inductors to generate different zero points, so that the nonlinear signal generated by the previous resonator can be suppressed on the output side of the filter 10, thereby improving the linearity of the filter 10.

[0059] In addition, the embodiment of the present application can meet different actual usage requirements by adjusting the values ​​of M and N, as well as the specific parameters of the resonator and the inductor. Therefore, the design of the filter 10 provided in the embodiment of the present application has high flexibility and scalability.

[0060] It should be noted that, since the first inductor L0 has a frequency response characteristic in the circuit, for high-frequency signals, the impedance of the inductor is proportional to the frequency (Z=jωL), where Z is the impedance, j is the imaginary unit, ω is the angular frequency, and L is the inductance value. In the design of the filter 10, impedance matching is very important. If the input or output impedance of the filter 10 does not match the impedance of the signal source or the load, it will cause signal reflection and loss, affecting the performance of the filter. The present application can adjust the impedance characteristics of the filter 10 within a specific frequency range by grounding the first inductor L0 at the second node, so that it better matches the impedance of the signal source and the load.

[0061] Correspondingly, for out-of-band high-frequency signals, the impedance of the first inductor L0 is very high, making it difficult for out-of-band high-frequency signals to reach the ground through the first inductor L0. Therefore, the out-of-band high-frequency signal will also encounter a high-impedance path when passing through the second resonator 12 and the third resonator 13 corresponding to the second node, further improving the out-of-band suppression capability. In some embodiments, the first port is the antenna terminal ANT, the second port is the transmitter terminal TX, and the filter 10 is used to filter the RF signal transmitted from TX to ANT.

[0062] In some embodiments, the first resonator 11 includes at least one of the following: a Bulk Acoustic Wave (BAW) resonator and a Surface Acoustic Wave (SAW) resonator.

[0063] Exemplarily, the first resonator 11 is a SAW resonator, which may be a normal surface acoustic wave (Normal SAW) resonator, a temperature compensated surface acoustic wave (TC-SAW) resonator, a thin film surface acoustic wave (TF-SAW) resonator, etc., which is not limited in the embodiments of the present application.

[0064] Exemplarily, the M first resonators 11 may be a cascade of M surface acoustic wave resonators, or a cascade of M individual acoustic wave resonators, or a cascade of A surface acoustic wave resonators and B individual acoustic wave resonators (A+B=M).

[0065] In some embodiments, the second resonator 12 includes at least one of the following: a Bulk Acoustic Wave (BAW) resonator and a Surface Acoustic Wave (SAW) resonator.

[0066] Exemplarily, the second resonator 12 is a SAW resonator, which may be a normal surface acoustic wave (Normal SAW) resonator, a temperature compensated surface acoustic wave (TC-SAW) resonator, a thin film surface acoustic wave (TF-SAW) resonator, etc., which is not limited in the embodiments of the present application.

[0067] Exemplarily, the N first resonators 11 may be N surface acoustic wave resonators, or may be N individual acoustic wave resonators, or may be a cascade connection of C surface acoustic wave resonators and D individual acoustic wave resonators (C+D=N).

[0068] In some embodiments, the third resonator 13 includes at least one of the following: a bulk acoustic wave (BAW) resonator and a surface acoustic wave (SAW) resonator; the BAW resonator includes, for example, a thin film bulk acoustic wave resonator, which is not limited in the embodiments of the present application.

[0069] Exemplarily, the third resonator 13 is a SAW resonator, which may be a normal surface acoustic wave (Normal SAW) resonator, a temperature compensated surface acoustic wave (TC-SAW) resonator, a thin film surface acoustic wave (TF-SAW) resonator, etc., which is not limited in the embodiments of the present application.

[0070] In some embodiments, Figure 1As shown, in the first direction, the first ends of the first N-1 second resonators 12 are connected between two adjacent first resonators 11, and the first end of the Nth second resonator 12 is connected between the Mth first resonator 11 and the second port. By connecting the first N-1 second resonators 12 in parallel between two adjacent first resonators 11, a ladder filter is formed, thereby filtering out a specific frequency in the signal or a signal other than the specific frequency.

[0071] In some embodiments, the zero frequency corresponding to the second node is lower than the zero frequency corresponding to the first node; wherein the zero frequency corresponding to the node is the resonant frequency of the static capacitance of the resonator connected to the node and the inductance connected to the node. For example, the zero frequency corresponding to the second node is 1.8f 0 , the zero frequency corresponding to the first node is 3.1f 0 , so that the interval between the two zero frequencies can cover 2f 0 To 3F 0 The interval between the two points can be set to the second-order harmonic (frequency 2f 0 , f 0 is the operating frequency of the filter 10) and the third-order harmonic (frequency is 3f 0 ) are suppressed, which improves the out-of-band suppression effect of the filter 10 while also improving the linearity of the filter.

[0072] As an implementation method, the filter 10 is integrated in the chip and packaged on the substrate by flip-chip, wherein the first node and the second node are connected to the substrate by different conductive bumps, respectively. Specifically, the first node is connected to the grounding metal on the substrate by a bump, thereby achieving grounding; since the bump has a small amount of parasitic inductance, at this time, the inductance connected to the first node can be regarded as the equivalent inductance of the bump, and the zero frequency corresponding to the first node is the resonant frequency of the equivalent inductance of the bump set at the first node and the static capacitance of each second resonator 12 connected to the first node.

[0073] When the first inductor L0 is disposed on the substrate, the second node is connected to one end of the first inductor L0 on the substrate through another bump, and the second end of the first inductor L0 is connected to the grounding metal on the substrate, so that the second node is grounded through the corresponding bump and the first inductor L0 in sequence. At this time, the inductor connected to the second node can be regarded as the sum of the equivalent inductance of the bump and the first inductor L0, and the zero-point frequency corresponding to the second node is the resonant frequency of the equivalent inductance of the bump disposed at the second node, the first inductor L0, and the static capacitance of each second resonator 12 connected to the first node.

[0074] In the embodiment of the present application, by designing the zero frequency of the second node to be lower than the zero frequency of the first node, the resonator and the inductor at the two nodes can generate two different zero points, thereby enhancing the attenuation capability of the filter 10 at the out-of-band frequency. This optimization helps to reduce out-of-band noise and interference and improve the overall performance of the communication system. The optimized zero frequency design enables the filter 10 to have a better out-of-band suppression effect in a wider frequency band, meeting the demand for frequency band expansion of modern communication systems.

[0075] Accordingly, by optimizing the zero-point frequency, the performance of the filter 10 in the high frequency band is improved, and the signal-to-noise ratio (SNR) is significantly improved, ensuring that high-quality signals can still be transmitted in complex environments. The optimized design of the zero-point frequency improves the frequency band selectivity of the filter 10. By making the zero-point frequency of the second node lower than the zero-point frequency of the first node, the performance of the filter 10 at the out-of-band frequency is significantly improved, effectively suppressing the interference of the out-of-band signal, so that the signal-to-noise ratio of the filter 10 in the target frequency band is improved.

[0076] Exemplarily, the relationship between the zero frequency corresponding to the first node and the operating frequency of the filter 10 is 2.8f 0 ≤f P1 , the relationship between the zero frequency corresponding to the second node and the operating frequency of the filter 10 is: 1.5f 0 ≤f P2 ≤2f 0 ; Among them, f 0 is the operating frequency of the filter 10, f P1 is the zero frequency corresponding to the first node, f P2 is the zero point frequency corresponding to the second node.

[0077] By setting the zero frequency of the first node f P1 Greater than or equal to 2.8f 0 , set the zero frequency of the second node at 1.5f 0 To 2f 0 The zero frequency of the filter can at least cover the frequency corresponding to the second-order harmonic (2f 0 ), which helps to suppress at least the second-order harmonics and improve the out-of-band attenuation capability of the filter 10.

[0078] It should be noted that, in some embodiments, the relationship between the zero frequency corresponding to the first node and the operating frequency of the filter 10 is 3f 0 ≤f P1 ; Among them, f 0 is the operating frequency of the filter 10, f P1 is the zero-point frequency corresponding to the first node.

[0079] By increasing the zero frequency of the first node from the above example to greater than or equal to 2.8f 0 Increase to greater than or equal to 3f 0 , the zero frequency of the first node is in a higher frequency range, which can more effectively suppress high-frequency noise and interference and improve the out-of-band attenuation capability of the filter 10 in the high frequency band.

[0080] At the same time, if Figure 2 As shown, the resonant frequency of the static capacitance of the resonator through the first node and the inductance connected to the node corresponds to a frequency higher than 3f 0 After the third resonator 13 is added, the parallel capacitance corresponding to the second node increases, and the position of the zero point corresponding to the resonant frequency moves to a low frequency, so that the resonant frequency corresponding to the static capacitance of the resonator at the second node is lower than 2f 0 Another zero point of , so that the interval between the two zero points can cover 2f 0 and 3f 0 The interval between the two points can be set to the second-order harmonic (frequency 2f 0 ) and the third-order harmonic (frequency 3f 0 ) are suppressed, thereby improving the out-of-band suppression effect of the filter 10 and the nonlinear performance of the filter 10.

[0081] In some embodiments, the capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node; the corresponding capacitance value is the capacitance value of the static capacitance of the resonator connected to the node.

[0082] As an implementation mode, the number of resonators connected to the second node may be set to be greater than the number of resonators connected to the first node, so that the capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node. For example, when the number of second resonators connected to the second node is the same as the number of second resonators connected to the first node, the third resonator 13 is connected to the second node, so that the number of resonators connected to the second node is greater than the number of resonators connected to the first node, so that the capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node.

[0083] Exemplarily, in the first direction, among the 2nd to Nth second resonators 12, the first node is connected to the second end of at least one second resonator 12, the second node is connected to the second ends of multiple different second resonators 12, and the number of second resonators 12 connected to the first node is less than the sum of the number of second resonators 12 connected to the second node and the number of third resonators 13.

[0084] Of course, in other embodiments, a capacitor device connected in parallel may be added to the second node. For example, when the number of resonators connected to the second node is the same as the number of resonators connected to the first node, a capacitor device may be connected in parallel across at least one second resonator connected to the second node or across a third resonator, thereby increasing the capacitance value corresponding to the second node.

[0085] By increasing the capacitance value of the second node (such as by connecting more second ends of the second resonators 12 to the second node), correspondingly, by increasing the capacitance value of the second node, the zero-point frequency corresponding to the second node can be moved toward a low frequency, and the difference between the zero-point frequency corresponding to the first node and the zero-point frequency corresponding to the second node can be increased, so that the range covered between the two zero-point frequencies is wider, thereby more effectively suppressing out-of-band noise and interference and further reducing nonlinear distortion.

[0086] For example, see Fig.13 and Fig.14 ,in Fig.13 This is a test result of a comparative example, that is, when no third resonator is provided, a CW wave (Continuous Wave) of 29 dBm is input to the second port of the filter 100 , and a second-order nonlinear curve H2 and a third-order nonlinear curve H3 are measured. Fig.14 This is the test result of an embodiment of the present application, specifically, a third resonator 13 arranged in parallel is added between the first two first resonators 11 close to the first port, and a 29dBm CW wave is input to the second port of the filter 100. The second-order nonlinear curve H2 and the third-order nonlinear curve H3 are measured.

[0087] It can be seen that in the comparative example, the value of the second-order nonlinear curve H2 is roughly in the range of -50dBm to -56dBm, and the value of the third-order nonlinear curve H3 is roughly in the range of -40dBm to -50dBm. In the embodiment, the value of the second-order nonlinear curve H2 is in the range of -60dBm to -65dBm, which is improved by 4 to 10dB compared with the comparative example; the value of the third-order nonlinear curve H3 is roughly in the range of -59dBm to -80dBm, which is improved by 10 to 30dB compared with the comparative example.

[0088] It can be seen that by adding a third resonator 13 connected in parallel between the first two first resonators 11 close to the RF signal output side, the second-order nonlinearity and third-order nonlinearity of the filter 10 can be significantly improved.

[0089] In some embodiments, Figure 3As shown, the provided filter 10 also includes: at least one fourth resonator 14, in the first direction, the first end of the fourth resonator 14 is connected between the first end of the first second resonator 12 and the first end of the third resonator 13, the second end of the fourth resonator 14 is connected to the third node, and the third node is used for grounding.

[0090] The introduction of the fourth resonator 14 and the third node provides an additional attenuation path between the first node and the second node. For example, the zero frequency corresponding to the second node is 1.8f. 0 , the frequency corresponding to the third node is 2.2f 0 , the zero frequency corresponding to the first node is 3.1f 0 , three different zero points can be generated through the resonators and inductors at these three nodes. In the out-of-band frequency range (2f 0 To 3F 0 ) has more zeros, the frequency response curve of the filter 10 is in the out-of-band frequency range (2f 0 To 3F 0 ) will be steeper, thus providing better out-of-band suppression.

[0091] Exemplarily, when the number of fourth resonators 14 between the first end of the first second resonator 12 and the first end of the third resonator 13 is multiple, the number of third nodes is also multiple, and each fourth resonator 14 is grounded through a corresponding third node. Then, multiple parallel paths can be added between the parallel paths corresponding to the first node and the second node according to specific needs to reduce the input power of the filter 10. The embodiment of the present application does not limit the number of fourth resonators 14.

[0092] Specifically, the zero-point frequency corresponding to the third node is located between the zero-point frequency corresponding to the first node and the zero-point frequency corresponding to the second node.

[0093] For example, the zero frequency corresponding to the third node is located at 2f 0 and 3f 0 By setting the zero frequency of the first node and the zero frequency of the second node to cover 2f 0 To 3F 0 And set the zero frequency corresponding to the third node at 2f 0 and 3f 0 Therefore, the frequency response curve of the filter 10 between the second harmonic and the third harmonic is steeper, which brings better out-of-band suppression effect, reduces the generation of intermodulation products such as the second harmonic and the third harmonic, further optimizes the frequency response of the filter 10, and improves the linearity of the filter 10.

[0094] In some embodiments, Figure 4As shown, it also includes: at least one fifth resonator 15, in the first direction, the first end of the fifth resonator 15 is connected to the first end of the j-th second resonator 12, the second end of the fifth resonator 15 is connected to the first node or the second node, or the second end of the fifth resonator 15 is connected to the fourth node, and the fourth node is used for grounding; wherein 2≤j≤N.

[0095] By introducing the fifth resonator 15 and connecting its first end to the first end of the i-th second resonator 12 (2≤j≤N), its second end can be connected to the first node or the second node, or can be grounded through the fourth node. When grounded through the fourth node, the grounding path of the fifth resonator 15 and the fourth node provides an additional attenuation path between the first node and the second node. The resonators and inductors at the first node, the second node and the fourth node can generate three different zero points, and the zero point frequencies corresponding to the three nodes can not only cover the out-of-band frequency range (2f 0 To 3F 0 ), and also enables the filter 10 to be at 2f 0 To 3F 0 The frequency response curve of the interval will be steeper, so that the attenuation capability of the filter 10 at the out-of-band frequency is significantly enhanced.

[0096] In some embodiments, the inductance value of the first inductor L0 ranges from 0.05 nH to 0.3 nH.

[0097] The inductance value range of the first inductor L0 is set to 0.05nH to 0.3nH. By adjusting the inductance value, the zero point position can be flexibly adjusted to meet the out-of-band suppression requirements in various scenarios, so that the filter 10 can match different application scenarios. The inductance of the first inductor L0 will affect the resonant frequency and impedance characteristics of the filter. Under different inductances, the frequency response curve of the filter will be different. By selecting a suitable inductance within the range of 0.05nH to 0.3nH, the filter can be made to have a good out-of-band frequency range (2f 0 To 3F 0 ) has a better suppression effect, which is crucial to the stability and reliability of signal transmission. At the same time, the appropriate inductance can improve the impedance matching inside the filter, reduce the reflection and energy loss caused by impedance mismatch, and thus reduce the irregular fluctuations in the frequency response. The selection of inductance can also avoid unnecessary resonance phenomena in the filter at certain frequency points, which will cause irregular fluctuations in the frequency response. A smooth frequency response curve can optimize the transmission characteristics of the filter, make the signal more stable when passing through the filter, reduce signal distortion and interference, and improve the reliability and stability of the filter 10.

[0098] At the same time, the appropriate ground inductance can more effectively suppress the nonlinear distortion caused by the high-power signal and improve the linearity of the filter 10. The ground inductance is adjusted so that the zero frequency distribution covers the frequency range corresponding to the second harmonic and the third harmonic (2f 0 To 3F 0 ), which can further suppress the second harmonic (H2) and third harmonic (H3), while improving out-of-band suppression and enhancing the signal-to-noise ratio.

[0099] For example, the inductance range can be further reduced to 0.1 nH to 0.2 nH according to usage requirements, thereby further improving the reliability and stability of the filter 10 .

[0100] In some embodiments, Figure 5 As shown, the first node is used to be grounded through the second inductor L1, and the inductance of the second inductor L1 is smaller than the inductance of the first inductor L0.

[0101] By setting the inductance of the second inductor L1 to be smaller than the inductance of the first inductor L0, the interval between the two zero frequencies can cover the range from the second harmonic to the third harmonic (2f 0 To 3F 0 ), thereby achieving the second-order harmonic (frequency 2f 0 ) and the third-order harmonic (frequency 3f 0 ) are suppressed, thereby improving the out-of-band suppression effect and linearity of the filter 10.

[0102] It should be noted that the second inductor L1 can also be implemented by a trace connected to the first node on the substrate on which the chip integrated with the filter 10 is provided. By making the trace length shorter (determining the trace length according to the actual inductance, such as being less than a preset length), the equivalent inductance connected to the first node is made the first inductor L1.

[0103] In some embodiments, the resonant frequency corresponding to the first second resonator 12 is a first resonant frequency, the resonant frequency corresponding to the third resonator 13 is a second resonant frequency, and the first resonant frequency is greater than the second resonant frequency.

[0104] By setting the resonant frequency of the first second resonator 12 to the first resonant frequency, and the first resonant frequency is greater than the second resonant frequency of the third resonator 13, a higher frequency selectivity can be provided in a wider frequency band, thereby better filtering out unwanted frequency components. The reasonable distribution of the first resonant frequency and the second resonant frequency can reduce the attenuation of the in-band signal and improve the transmission efficiency and quality of the in-band signal. At the same time, by reasonably setting the resonant frequency, the interference of the out-of-band signal can be more effectively suppressed, and the out-of-band suppression capability of the filter 10 can be improved.

[0105] In some embodiments, the filter 10 is integrated in a chip, and the chip and the first inductor L0 are both arranged on a substrate; wherein, at least a first conductive bump and a second conductive bump are arranged on the chip, the first conductive bump is used to connect the first node and the ground terminal on the substrate, the second conductive bump is used to connect the second node and the first end of the first inductor L0, and the second end of the first inductor L0 is connected to the ground terminal on the substrate.

[0106] By integrating the filter 10 into the chip, the volume and weight of the filter 10 can be significantly reduced, and the integration of the entire system can be improved, making it more compact and portable. Through chip integration, parasitic parameters introduced by external connecting wires and solder joints can be reduced, and the performance and reliability of the filter 10 can be improved.

[0107] The use of the first conductive bump (such as Bump1) and the second conductive bump (such as Bump 2) can optimize the signal path, reduce the loss and noise during the signal transmission process, and improve the signal transmission efficiency. The filter 10 integrated in the chip can maintain stable performance within a wider temperature range, reduce the impact of environmental factors on the performance of the filter 10, and improve the reliability and stability of the system. The chip-integrated design makes the production and packaging of the filter 10 more convenient and efficient, reduces production costs, and improves production efficiency. By optimizing the connection method between the conductive bump and the substrate, the chip-integrated filter 10 has higher stability and lower noise within a wider frequency band, meeting the requirements of modern communication systems for high stability.

[0108] At the same time, if Figure 3 and Figure 4 As shown, when the filter 10 has a third node and a fourth node, at least a third conductive bump and a fourth conductive bump are provided on the chip, the third conductive bump is used to connect the third node and the ground terminal on the substrate, and the fourth conductive bump is used to connect the fourth node and the ground terminal on the substrate. The number of conductive bumps can be adjusted arbitrarily according to actual needs, and the embodiment of the present application does not limit this.

[0109] It should be noted that there may be multiple grounding terminals on the substrate, and the grounding terminals connected to the first conductive bump and the second conductive bump mentioned in this embodiment may be the same or different. At the same time, all metal patterns used for grounding on the substrate can be understood as grounding terminals, not just the ports at the edge.

[0110] In some embodiments, the influence range of the first resonant frequency on the zero-point frequency corresponding to the first node is within a preset variation range, and the preset variation range is -100 MHZ to 100 MHZ.

[0111] By limiting the influence range of the first resonant frequency on the zero frequency of the first node to -100 MHz to 100 MHz, the zero frequency of the filter 10 can be more accurately controlled. This precise control makes the filter 10 more selective in the high frequency band and can more effectively filter out unwanted frequency components.

[0112] In some embodiments, the influence range of the second resonant frequency on the zero-point frequency corresponding to the second node is within a preset variation range, and the preset variation range is -100 MHZ to 100 MHZ.

[0113] By limiting the influence range of the second resonant frequency on the zero frequency of the second node to -100 MHz to 100 MHz, the zero frequency of the filter 10 can be more accurately controlled. This precise control makes the filter 10 more selective in the mid-frequency band and can more effectively filter out unwanted frequency components.

[0114] It should be noted that the number M of the first resonators 11 and the number N of the second resonators 12 can be set according to specific requirements, and the embodiment of the present application does not limit this.

[0115] In some embodiments, Figure 6 As shown, M=4, N=4, in the first direction, the second ends of the first and second second resonators 12 are connected to the first node, and the second ends of the third and fourth second resonators 12 and the third resonator 13 are connected to the second node, so that the capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node, and the zero-point frequency corresponding to the second node is lower than the zero-point frequency corresponding to the first node, which helps to maintain the linear operation of the filter 10 under high power conditions and significantly improve the suppression capability of the filter 10 at out-of-band frequencies.

[0116] It should be noted that the filter 10 provided may be as follows: Figure 1 As shown, the first end of the first second resonator 12 in the first direction is close to the first first resonator 11, or the first end of the third resonator 13 can be close to the first first resonator 11, which is not limited in the embodiment of the present application.

[0117] It should be noted that, in the first direction, any first resonator 11 may include a plurality of sub-resonators connected in series, which is not limited in this embodiment of the present application.

[0118] See also Figure 7 The embodiment of the present application further provides a filter 10 , including a first port, a second port, M first resonators 11 , N second resonators 12 and a third resonator 13 .

[0119] The filter 10 is used to filter the radio frequency signal transmitted from the second port to the first port. M first resonators 11 are connected in series between the first port and the second port, wherein M is a positive integer greater than or equal to 2. The first end of the second resonator 12 is connected between two adjacent first resonators 11, and in the first direction, the second end of at least the kth second resonator 12 is connected to the first node, and the second end of at least one other second resonator 12 is connected to the second node, wherein the first node is used for grounding, and the second node is used for grounding through the first inductor L0. The first end of the third resonator 13 is connected between the kth first resonator 11 and the k+1th first resonator 11 in the first direction, and the second end of the third resonator 13 is connected to the second node. Wherein, k is a positive integer and 1≤k≤N, and the first direction is the direction from the first port to the second port.

[0120] Specifically, the filter 10 provided in the present application forms a multi-stage resonator by introducing a plurality of resonator structures connected in series and in parallel, thereby filtering out a specific frequency in the signal or a signal other than a specific frequency. By setting two nodes to access different inductors, the multi-stage resonator can generate at least two zero points with different inductors, thereby improving the suppression of out-of-band noise. On this basis, the filter 10 adds a third resonator 13 in parallel between the kth first resonator 11 and the k+1th first resonator 11 in the first direction, that is, a second resonator 12 and a third resonator 13 are connected in parallel between the kth first resonator 11 and the k+1th first resonator 11, and the second resonator 12 and the third resonator 13 are connected to different nodes, that is, they resonate with different inductors, thereby improving the out-of-band suppression capability, and effectively solving the nonlinear problem and insufficient out-of-band suppression problem of the traditional SAW filter at high power input.

[0121] In some embodiments, the zero-point frequency corresponding to the second node is lower than the zero-point frequency corresponding to the first node, wherein the zero-point frequency corresponding to the node is the resonant frequency of the static capacitance of the resonator connected to the node and the inductance connected to the node.

[0122] Exemplarily, the relationship between the zero frequency corresponding to the first node and the operating frequency of the filter 10 is 2.8f 0 ≤f P1 , the relationship between the zero frequency corresponding to the second node and the operating frequency of the filter 10 is: 1.5f 0 ≤f P2 ≤2f 0 ; Among them, f 0 is the operating frequency of the filter 10, f P1 is the zero frequency corresponding to the first node, f P2 is the zero point frequency corresponding to the second node.

[0123] It should be noted that, in some embodiments, the relationship between the zero frequency corresponding to the first node and the operating frequency of the filter 10 is 3f 0 ≤f P1 ; Among them, f 0 is the operating frequency of the filter 10, f P1 is the zero-point frequency corresponding to the first node.

[0124] In some embodiments, the capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node, wherein the capacitance value corresponding to the node is the static capacitance value of the resonator connected to the node.

[0125] Exemplarily, if the capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node, in the first direction, within the preset range corresponding to the second resonator 12, the first node is connected to the second end of at least one second resonator 12, the second node is connected to the second ends of multiple different second resonators 12, and the number of second resonators 12 connected to the first node is less than the sum of the number of second resonators 12 connected to the second node and the number of third resonators 13; wherein the preset range includes [1, k)U(k, N].

[0126] In some embodiments, in the first direction, the first ends of the first N-1 second resonators 12 are connected between two adjacent first resonators 11 , and the first end of the Nth second resonator 12 is connected between the Mth first resonator 11 and the second port.

[0127] In some embodiments, the filter 10 is integrated in a chip, and the chip and the first inductor L0 are both arranged on a substrate; wherein, at least a first conductive bump and a second conductive bump are arranged on the chip, the first conductive bump is used to connect the first node and the ground terminal on the substrate, the second conductive bump is used to connect the second node and the first end of the first inductor L0, and the second end of the first inductor L0 is connected to the ground terminal on the substrate.

[0128] In some embodiments, Figure 8 As shown, it also includes: at least one fourth resonator 14, in the first direction, the first end of the fourth resonator 14 is connected between the first end of the kth second resonator 12 and the first end of the third resonator 13, the second end of the fourth resonator 14 is connected to the third node, and the third node is used for grounding.

[0129] Exemplarily, the zero-point frequency corresponding to the third node is located between the zero-point frequency corresponding to the first node and the zero-point frequency corresponding to the second node.

[0130] In some embodiments, Fig. 9As shown, it also includes: at least one fifth resonator 15, in the first direction, the first end of the fifth resonator 15 is connected to the first end of the mth second resonator 12, the second end of the fifth resonator 15 is connected to the first node or the second node, or the second end of the fifth resonator 15 is connected to the fourth node, and the fourth node is used for grounding; wherein 1≤m<k, and k<m≤N.

[0131] In some embodiments, the inductance of the first inductor L0 ranges from 0.05 nH to 0.3 nH.

[0132] In some embodiments, Fig.10 As shown, the first node is used to be grounded through the first inductor L1, and the inductance of the first inductor L1 is smaller than the inductance of the first inductor L0.

[0133] In some embodiments, the resonant frequency corresponding to the first second resonator 12 is a first resonant frequency, the resonant frequency corresponding to the third resonator 13 is a second resonant frequency, and the first resonant frequency is greater than the second resonant frequency.

[0134] It should be noted that those skilled in the art can clearly understand that for the convenience and simplicity of description, the contents of the various embodiments corresponding to the above filter 10 can refer to Figures 1 to 6 The relevant contents in the embodiment of the corresponding filter 10 are not repeated here.

[0135] See also Figure 1 The embodiment of the present application also provides a filter 10, including a first port, a second port, M first resonators 11, N second resonators 12 and a third resonator 13.

[0136] The filter 10 is used to filter the radio frequency signal transmitted from the second port to the first port. M first resonators 11 are connected in series between the first port and the second port, wherein M is a positive integer greater than or equal to 2. The second resonator 12 is connected between two adjacent first resonators 11; in the first direction, the second end of the first second resonator 12 is connected to the first node; in the second to Nth second resonators 12, the first node is connected to the second end of at least one second resonator 12, and the second node is connected to the second ends of multiple different second resonators 12; the first node and the second node are both used for grounding. The first end of the third resonator 13 is connected between the first first resonator 11 and the second first resonator 11 in the first direction, and the second end of the third resonator 13 is connected to the second node; wherein the first direction is the direction from the first port to the second port; the capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node; the corresponding capacitance value is the capacitance value of the static capacitance of the resonator connected to the node.

[0137] Specifically, by introducing the third resonator 13 between the first two first resonators 11 in the first direction and adjusting the operating frequency and static capacitance value of the third resonator 13 , the nonlinear effect generated by the previous resonator can be further suppressed and the linearity of the filter 10 can be improved.

[0138] At the same time, by introducing multiple parallel second resonators 12 at the connection nodes between the multiple first resonators 11, and connecting their second ends to different ground nodes (first node and second node), the out-of-band suppression capability of the filter 10 can be enhanced. By setting the capacitance value corresponding to the second node to be greater than the capacitance value corresponding to the first node, the difference between the zero-point frequency corresponding to the first node and the zero-point frequency corresponding to the second node can be increased, so that the frequency range covered between the two zero points is wider, and the suppression effect of the out-of-band signal is further improved. Furthermore, the design of the filter 10 effectively improves the out-of-band suppression and nonlinear problems by adjusting the number and connection method of the resonators.

[0139] In some embodiments, Figure 1 As shown, the second node is grounded through the first inductor L0.

[0140] In some embodiments, the zero frequency corresponding to the second node is lower than the zero frequency corresponding to the first node; wherein the zero frequency corresponding to the node is the resonant frequency of the static capacitance of the resonator connected to the node and the inductance connected to the node.

[0141] Exemplarily, the relationship between the zero frequency corresponding to the first node and the operating frequency of the filter 10 is 2.8f 0 ≤f P1 , the relationship between the zero frequency corresponding to the second node and the operating frequency of the filter 10 is: 1.5f 0 ≤f P2 ≤2f 0 ; Among them, f 0 is the operating frequency of the filter 10, f P1 is the zero frequency corresponding to the first node, f P2 is the zero point frequency corresponding to the second node.

[0142] It should be noted that, in some embodiments, the relationship between the zero frequency corresponding to the first node and the operating frequency of the filter 10 is 3f 0 ≤f P1 ; Among them, f 0 is the operating frequency of the filter 10, f P1 is the zero-point frequency corresponding to the first node.

[0143] In some embodiments, the zero frequency corresponding to the second node is lower than the zero frequency corresponding to the first node, and the zero frequency corresponding to the node is the resonant frequency of the static capacitance of the resonator connected to the node and the inductance connected to the node.

[0144] In some embodiments, the number of second resonators 12 connected to the first node is less than the sum of the number of second resonators 12 connected to the second node and the number of third resonators 13 .

[0145] In some embodiments, the filter 10 is integrated in a chip, and the chip and the first inductor L0 are both arranged on a substrate; wherein, at least a first conductive bump and a second conductive bump are arranged on the chip, the first conductive bump is used to connect the first node and the ground terminal on the substrate, the second conductive bump is used to connect the second node and the first end of the first inductor L0, and the second end of the first inductor L0 is connected to the ground terminal on the substrate.

[0146] In some embodiments, Figure 3 As shown, it also includes: at least one fourth resonator 14, in the first direction, the first end of the fourth resonator 14 is connected between the first end of the second resonator 12 and the first end of the third resonator 13, the second end of the fourth resonator 14 is connected to the third node, and the third node is used for grounding.

[0147] Exemplarily, the zero-point frequency corresponding to the third node is located between the zero-point frequency corresponding to the first node and the zero-point frequency corresponding to the second node.

[0148] In some embodiments, Figure 4 As shown, it also includes: at least one fifth resonator 15, in the first direction, the first end of the fifth resonator 15 is connected to the first end of the j-th second resonator 12, the second end of the fifth resonator 15 is connected to the first node or the second node, or the second end of the fifth resonator 15 is connected to the fourth node, and the fourth node is used for grounding; wherein 2≤j≤N.

[0149] In some embodiments, the inductance of the first inductor L0 ranges from 0.05 nH to 0.3 nH.

[0150] In some embodiments, Figure 5 As shown, the first node is used to be grounded through the first inductor L1, and the inductance of the first inductor L1 is smaller than the inductance of the first inductor L0.

[0151] In some embodiments, the resonant frequency corresponding to the first second resonator 12 is a first resonant frequency, the resonant frequency corresponding to the third resonator 13 is a second resonant frequency, and the first resonant frequency is greater than the second resonant frequency.

[0152] It should be noted that those skilled in the art can clearly understand that for the convenience and simplicity of description, the contents of the various embodiments corresponding to the above filter 10 can refer to Figures 1 to 6 The relevant contents in the embodiment of the corresponding filter 10 are not repeated here.

[0153] Please refer to the above examples. Fig.11 , is a schematic diagram of a multiplexer 20 provided in some embodiments of the present application.

[0154] like Fig.11 As shown, the multiplexer 20 includes at least two filters, and at least one of the at least two filters is the filter 10 provided by any embodiment of the present application.

[0155] In some implementations, the multiplexer 20 may be a duplexer or a triplexer.

[0156] The specific principle and implementation method of the multiplexer 20 provided in the embodiment of the present application are similar to those of the filter 10 in the aforementioned embodiment, and will not be repeated here.

[0157] Please refer to the above examples. Fig.12 The embodiment of the present application further provides a schematic diagram of a radio frequency front-end module 30. The radio frequency front-end module 30 includes the filter 10 provided in any embodiment of the present application, for example, includes the aforementioned multiplexer 20.

[0158] The RF front-end module 30 is a component that integrates two or more discrete devices such as a RF switch, a low noise amplifier, a coupler, a filter 10, and a multiplexer 20 into an independent module, thereby improving the integration and hardware performance and miniaturizing the volume. Specifically, the RF front-end module 30 can be applied to communication devices such as smart phones, tablet computers, and smart watches. The RF front-end module 30 is, for example, a RF front-end module 30 applied to communication devices such as LTE (Long Term Evolution, referred to as LTE) and 5G.

[0159] Optionally, the RF front-end module 30 may include at least one of an RF transmission link and an RF receiving link. As an implementation mode, the RF front-end module 30 includes an RF transmission link, and the filter 10 is applied in the RF transmission link. Specifically, in addition to the filter 10, the RF transmission link may also include a power amplifier, an RF switch, and an antenna port. The second port of the filter 10 may be used to receive the RF signal output by the power amplifier. The filter 10 filters the received RF signal and outputs it through the first port. The first port of the filter 10 may be connected to the antenna end through the RF switch.

[0160] As an implementation mode, the RF front-end module 30 includes an RF receiving link, and the filter 10 is applied in the RF receiving link. Specifically, in addition to the filter 10, the RF receiving link may also include a low-noise amplifier, an RF switch and an antenna port. The filtered signal received by the antenna port is input to the second port of the filter 10 after passing through the RF switch. The filter 10 filters the received RF signal and outputs it through the first port. The first port of the filter 10 can be connected to a low-noise amplifier, so as to output the filtered RF signal to the low-noise amplifier for amplification.

[0161] As an implementation mode, the RF front-end module 30 may include an RF transmission link and an RF reception link, wherein the filter 10 in the RF transmission link and the filter 10 in the RF reception link may be integrated in the same chip to form a duplexer, or may be respectively arranged in different chips. Exemplarily, the RF transmission link and the RF reception link may share the same RF switch and the same antenna port.

[0162] The specific principles and implementation methods of the RF front-end module provided in the embodiments of the present application are similar to those of the filter or multiplexer in the aforementioned embodiments and will not be repeated here.

[0163] It should be understood that the terms used in this application are only for the purpose of describing a specific embodiment and are not intended to limit the application. It should be understood that when an element or layer is referred to as "on ... ", "adjacent to ... ", "connected to " or "coupled to " other elements or layers, it can be directly on other elements or layers, adjacent to it, connected or coupled to other elements or layers, or there can be an intermediate element or layer. On the contrary, when an element is referred to as "directly on ... ", "directly adjacent to ... ", "directly connected to " or "directly coupled to " other elements or layers, there is no intermediate element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish an element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teaching of the application, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part.

[0164] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that the spatially relative terms are intended to include different orientations of the device in use and operation in addition to the orientations shown in the figures. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0165] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0166] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0167] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A filter, characterized in that: include: a first port and a second port, wherein the filter is used to filter the radio frequency signal transmitted from the second port to the first port; M first resonators, the M first resonators are connected in series between the first port and the second port, wherein M is a positive integer greater than or equal to 2; N second resonators, wherein the first end of the second resonator is connected between two adjacent first resonators; in a first direction, the second end of the first second resonator is connected to a first node, and the second end of at least one of the second resonators from the second to the Nth second resonators is connected to a second node; wherein the first node is used for grounding, and the second node is used for grounding through a first inductor; a third resonator, wherein a first end of the third resonator is connected between a first first resonator and a second first resonator in the first direction, and a second end of the third resonator is connected to the second node; The first direction is a direction from the first port to the second port.

2. The filter according to claim 1, characterized in that In the first direction, the first ends of the first N-1 second resonators are connected between two adjacent first resonators, and the first end of the Nth second resonator is connected between the Mth first resonator and the second port.

3. The filter according to claim 1, characterized in that The zero-point frequency corresponding to the second node is lower than the zero-point frequency corresponding to the first node; wherein the zero-point frequency corresponding to the node is the resonant frequency of the static capacitance of the resonator connected to the node and the inductance connected to the node.

4. The filter according to claim 3, characterized in that The relationship between the zero frequency corresponding to the first node and the operating frequency of the filter is 2.8f0≤f P1 , the relationship between the zero frequency corresponding to the second node and the operating frequency of the filter is: 1.5f0≤f P2 ≤2f0;. Wherein, f0 is the operating frequency of the filter, f P1 is the zero frequency corresponding to the first node, f P2 is the zero point frequency corresponding to the second node.

5. The filter according to claim 4, characterized in that The relationship between the zero frequency corresponding to the first node and the operating frequency of the filter is 3f0≤f P1 ; Wherein, f0 is the operating frequency of the filter, f P1 is the zero-point frequency corresponding to the first node.

6. The filter according to claim 1, characterized in that The filter is integrated in the chip, and the chip and the first inductor are both arranged on a substrate; Among them, at least a first conductive bump and a second conductive bump are provided on the chip, the first conductive bump is used to connect the first node and the ground terminal on the substrate, the second conductive bump is used to connect the second node and the first end of the first inductor, and the second end of the first inductor is connected to the ground terminal on the substrate.

7. The filter according to claim 1, characterized in that The capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node; wherein the capacitance value corresponding to the node is the capacitance value of the static capacitance of the resonator connected to the node.

8. The filter according to claim 7, characterized in that In the first direction, among the 2nd to Nth second resonators, the first node is connected to the second end of at least one second resonator, the second node is connected to the second ends of multiple different second resonators, and the number of second resonators connected to the first node is less than the sum of the number of second resonators connected to the second node and the number of the third resonators.

9. The filter according to claim 1, characterized in that Also includes: At least one fourth resonator, in the first direction, a first end of the fourth resonator is connected between the first end of the second resonator and the first end of the third resonator, a second end of the fourth resonator is connected to the third node, and the third node is used for grounding.

10. The filter according to claim 9, characterized in that The zero-point frequency corresponding to the third node is located between the zero-point frequency corresponding to the first node and the zero-point frequency corresponding to the second node.

11. The filter according to claim 1, characterized in that Also includes: at least one fifth resonator, in the first direction, the first end of the fifth resonator is connected to the first end of the jth second resonator, the second end of the fifth resonator is connected to the first node or the second node, or the second end of the fifth resonator is connected to a fourth node, and the fourth node is used for grounding; wherein 2≤j≤N.

12. The filter according to claim 1, characterized in that The inductance of the first inductor ranges from 0.05nH to 0.3nH.

13. The filter according to claim 1, characterized in that The first node is used to be grounded through a second inductor, and the inductance of the second inductor is smaller than the inductance of the first inductor.

14. The filter according to claim 1, characterized in that The resonance frequency corresponding to the first second resonator is a first resonance frequency, the resonance frequency corresponding to the third resonator is a second resonance frequency, and the first resonance frequency is greater than the second resonance frequency.

15. A filter, characterized in that: include: a first port and a second port, wherein the filter is used to filter the radio frequency signal transmitted from the second port to the first port; M first resonators, the M first resonators are connected in series between the first port and the second port, wherein M is a positive integer greater than or equal to 2; N second resonators, wherein a first end of each second resonator is connected between two adjacent first resonators, and in a first direction, a second end of at least the kth second resonator is connected to a first node, and a second end of at least one other second resonator is connected to a second node, wherein the first node is used for grounding, and the second node is used for grounding through a first inductor; a third resonator, wherein a first end of the third resonator is connected between the kth first resonator and the k+1th first resonator in the first direction, and a second end of the third resonator is connected to the second node; Wherein, k is a positive integer and 1≤k≤N, and the first direction is a direction from the first port to the second port.

16. The filter according to claim 15, characterized in that The zero point frequency corresponding to the second node is lower than the zero point frequency corresponding to the first node; and / or, The capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node; The zero-point frequency corresponding to the node is the resonant frequency of the static capacitance of the resonator connected to the node and the inductance connected to the node, and the capacitance value corresponding to the node is the static capacitance value of the resonator connected to the node.

17. The filter according to claim 16, characterized in that If the capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node, in the first direction, within the preset range corresponding to the second resonator, the first node is connected to the second end of at least one of the second resonators, the second node is connected to the second ends of a plurality of different second resonators, and the number of second resonators connected to the first node is less than the sum of the number of second resonators connected to the second node and the number of the third resonators; The preset range includes [1, k)∪(k, N].

18. A filter, characterized in that: include: a first port and a second port, wherein the filter is used to filter the radio frequency signal transmitted from the second port to the first port; M first resonators, the M first resonators are connected in series between the first port and the second port, wherein M is a positive integer greater than or equal to 2; N second resonators, wherein the second resonators are connected between two adjacent first resonators; in the first direction, the second end of the first second resonator is connected to the first node; in the second to Nth second resonators, the first node is connected to the second end of at least one second resonator, and the second node is connected to the second ends of multiple different second resonators; the first node and the second node are both used for grounding; a third resonator, wherein a first end of the third resonator is connected between a first first resonator and a second first resonator in the first direction, and a second end of the third resonator is connected to the second node; Among them, the first direction is the direction from the first port to the second port; the capacitance value corresponding to the second node is greater than the capacitance value corresponding to the first node; the corresponding capacitance value is the capacitance value of the static capacitance of the resonator connected to the node.

19. The filter according to claim 18, characterized in that The second node is grounded via a first inductor; and / or, The zero-point frequency corresponding to the second node is lower than the zero-point frequency corresponding to the first node, and the zero-point frequency corresponding to the node is the resonant frequency of the static capacitance of the resonator connected to the node and the inductance connected to the node; and / or, The number of the second resonators connected to the first node is less than the sum of the number of the second resonators connected to the second node and the number of the third resonators.

20. A multiplexer, characterized in that: The multiplexer comprises at least two filters, at least one of the at least two filters is the filter according to any one of claims 1-14, or the filter according to any one of claims 15-17, or the filter according to any one of claims 18-19.

21. A radio frequency front-end module, characterized in that: The RF front-end module includes: the filter according to any one of claims 1-14, or the filter according to any one of claims 15-17, or the filter according to any one of claims 18-19.

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