Filter circuit and radio frequency front-end module

Abstract

The invention provides a filter circuit and a radio frequency front-end module, and relates to the technical field of filtering. The filter circuit comprises a resonance assembly, a coupling capacitor and / or a coupling inductor. The resonance assembly comprises at least two resonance units, and part or all of the resonance units are connected with a coupling capacitor in parallel to form a capacitor cross coupling circuit. And / or part or all of the resonance units are connected through a coupling inductor to form an inductive coupling circuit so as to improve the quality factor of the filter circuit. On the basis, the filtering scheme provided by the invention can solve the problems of complex filtering circuit and low circuit integration level in the prior art, and meanwhile, the index performance of the filter can be improved on the basis of low cost.

Description

Technical Field

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

[0002] Filters are essential components in the RF front-end of wireless communications. With the development of wireless communication technologies such as 5G communications and the Internet of Things, the demand for filters in the RF front-end has greatly increased, and the development of filters has gradually tended towards low cost, high integration and miniaturization.

[0003] Filters in existing integrated circuits are often implemented using low temperature co-fired ceramic (LTCC) or printed circuit board (PCB) processes, but some filters cannot meet wireless communication scenarios that have high requirements for chip performance or cost. Existing high-performance filters, such as acoustic filters, are often too expensive.

[0004] Based on this, there is an urgent need for a filtering solution that can improve the performance of the filter at a low cost. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a filter circuit and a radio frequency front-end module, which can improve the index performance of the filter on the basis of low cost.

[0006] In order to achieve the above purpose, the technical solution adopted by the embodiment of the present invention is as follows:

[0007] In a first aspect, the present invention provides a filter circuit, the filter circuit comprising a resonant component, a coupling capacitor and / or a coupling inductor; the resonant component comprises at least two resonant units;

[0008] Some or all of the resonant units are connected in parallel with a coupling capacitor to form a capacitive cross-coupling circuit;

[0009] And / or some or all of the resonant units are connected via a coupling inductor to form an inductive coupling circuit to improve the quality factor of the filter circuit.

[0010] Optionally, when the resonant component forms a T-type inductor structure, the filter circuit also includes a first π-type capacitor structure, a second π-type capacitor structure and a first coupling capacitor. The first π-type capacitor structure is connected in series with the second π-type capacitor structure through the T-type inductor structure to form a series branch; the first coupling capacitor is connected in parallel with the series branch.

[0011] Optionally, the filter circuit further includes at least one filter unit, a first end of the filter unit is connected to an input / output port of the filter circuit, and a second end of the filter unit is connected to an input end of the first π-type capacitor structure.

[0012] Optionally, when the filter circuit includes a resonant component and a coupling capacitor, the resonant component also includes a common inductor and at least two resonant units, wherein the resonant units are arranged in parallel and are all grounded through the common inductor to form a T-type inductor structure.

[0013] Optionally, when the resonant component includes a first resonant unit, a second resonant unit, and a common inductor, the first resonant unit includes a first inductor and a first capacitor; the second resonant unit includes a second inductor and a second capacitor;

[0014] The first end of the first capacitor and the first end of the second capacitor are both grounded; the second end of the first capacitor is respectively connected to the first end of the first inductor and the second end of the first π-type capacitor structure; the second end of the second capacitor is respectively connected to the first end of the second inductor and the second end of the second π-type capacitor structure; the second end of the first inductor is respectively connected to the second end of the second inductor and the first end of the common inductor; the second end of the common inductor is grounded.

[0015] Optionally, the first π-type capacitor structure includes a third capacitor and a fourth capacitor, wherein the first end of the third capacitor is connected to the first end of the first coupling capacitor and the first end of the fourth capacitor respectively; the second end of the third capacitor is connected to the second end of the first capacitor; and the second end of the fourth capacitor is grounded;

[0016] The second π-type capacitor structure includes a fifth capacitor and a sixth capacitor; the first end of the fifth capacitor is respectively connected to the second end of the first coupling capacitor and the first end of the sixth capacitor; the second end of the fifth capacitor is connected to the second end of the second capacitor; and the second end of the sixth capacitor is grounded.

[0017] Optionally, when the filter circuit includes a resonant component, a coupling capacitor and a coupling inductor, and the resonant component includes a plurality of resonant units, two adjacent resonant units are connected via a coupling inductor so that the two adjacent resonant units have inductive coupling;

[0018] For any resonance unit, the current resonance unit and the corresponding target resonance unit are capacitively coupled via a coupling capacitor; the target resonance unit is used to represent the remaining resonance units except the resonance unit adjacent to the current resonance unit;

[0019] Wherein, any resonance unit corresponds to at least one target resonance unit.

[0020] Optionally, when the resonant component includes a third resonant unit, a fourth resonant unit, a fifth resonant unit, and a sixth resonant unit, the filter circuit further includes a first coupling inductor, a second coupling inductor, a third coupling inductor, a second coupling capacitor, and a third coupling capacitor;

[0021] The first end of the third coupling capacitor is connected to the first end of the second coupling capacitor and the first end of the third resonance unit respectively; the second end of the third coupling capacitor is connected to the second end of the sixth resonance unit; the second end of the second coupling capacitor is connected to the second end of the fifth resonance unit; the second end of the third resonance unit is connected to the first end of the fourth resonance unit through the first coupling inductor; the second end of the fourth resonance unit is connected to the first end of the fifth resonance unit through the second coupling inductor; and the second end of the fifth resonance unit is also connected to the first end of the sixth resonance unit through the third coupling inductor.

[0022] Optionally, the filter circuit further includes at least one resonator chip, and the resonator chip is arranged in parallel at an input / output port of the filter circuit.

[0023] In a second aspect, the present invention further provides a radio frequency front-end module, comprising the filter circuit described in any one of the first aspects above.

[0024] The filter circuit and radio frequency front-end module provided by the embodiments of the present invention have the following beneficial effects:

[0025] The present invention provides a filter circuit and a radio frequency front-end module, wherein the filter circuit includes a resonance component, a coupling capacitor and / or a coupling inductor; the resonance component includes at least two resonance units; some or all of the resonance units are connected in parallel with a coupling capacitor to form a capacitor cross-coupling circuit; and / or some or all of the resonance units are connected through a coupling inductor to form an inductive coupling circuit to improve the quality factor of the filter circuit. Based on this, a filtering scheme provided by the present invention can effectively reduce the inductance and capacitance values ​​while ensuring the resonant frequency, thereby effectively improving the inductance Q value and increasing the capacitance density in the same space, thereby solving the problem of complex filter circuits and low circuit integration in the prior art, and improving the index performance of the filter on the basis of low cost.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 One of the structural schematic diagrams of the filter circuit provided by the embodiment of the present invention is shown;

[0029] Figure 2 The second structural schematic diagram of the filter circuit provided by the embodiment of the present invention is shown;

[0030] Figure 3 The third structural schematic diagram of the filter circuit provided by the embodiment of the present invention is shown;

[0031] Figure 4 One of the circuit principle diagrams of the filter circuit provided by the embodiment of the present invention is shown;

[0032] Figure 5 The second circuit schematic diagram of the filter circuit provided by the embodiment of the present invention is shown;

[0033] Figure 6 A fourth structural schematic diagram of a filter circuit provided by an embodiment of the present invention is shown;

[0034] Figure 7 A fifth structural schematic diagram of a filter circuit provided by an embodiment of the present invention is shown;

[0035] Figure 8 The third circuit schematic diagram of the filter circuit provided by the embodiment of the present invention is shown;

[0036] Fig. 9 One of the structural schematic diagrams of the filter chip provided by the embodiment of the present invention is shown;

[0037] Fig.10 A sixth structural schematic diagram of a filter circuit provided by an embodiment of the present invention is shown;

[0038] Fig.11 The second structural schematic diagram of the filter chip provided by the embodiment of the present invention is shown;

[0039] Fig.12 shows the simulation results before adding capacitive coupling;

[0040] Fig.13 The simulation result of the filter circuit corresponding to the first embodiment of the present invention is shown;

[0041] Fig.14The simulation result of the filter circuit corresponding to the second embodiment of the present invention is shown;

[0042] Fig.15 The simulation result of the filter circuit corresponding to the third embodiment of the present invention is shown.

[0043] Icons: 10-filter circuit; 11-resonance component; 12-coupling capacitor; 13-coupling inductor; 21-resonance unit; 22-T-type inductor structure; 23-first π-type capacitor structure; 24-second π-type capacitor structure; Cs-first coupling capacitor; 25-filter unit; 31-first resonant unit; 32-second resonant unit; 33-third resonant unit; 34-fourth resonant unit; 35-fifth resonant unit; 36-sixth resonant unit; 100-filter chip; 101-capacitor dielectric layer; 102-inductor dielectric layer; 103-first metal grounding layer; 104-second metal grounding layer; 105-resonator chip layer; 200-resonator chip; 201-first resonator chip; 202-second resonator chip; 203-third resonator chip;

[0044] L1-first inductor; C1-first capacitor; L2-second inductor; C2-second capacitor; C3-third capacitor; C4-fourth capacitor; C5-fifth capacitor; C6-sixth capacitor; L3-common inductor; L4-first coupled inductor; L5-second coupled inductor; L6-third coupled inductor; C7-second coupled capacitor; C8-third coupled capacitor. DETAILED DESCRIPTION

[0045] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0046] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0047] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0048] As described in the background technology, filters in existing integrated circuits are usually implemented using LTCC or PCB board-level processes, which cannot meet some application scenarios with high requirements for chip performance or cost, while existing high-performance filters, such as acoustic filters, are often too expensive.

[0049] Based on this, the present invention provides a filter circuit and a radio frequency front-end module, which can improve the index performance of the filter on the basis of low cost.

[0050] The above-mentioned filtering circuit and RF front-end module solution will be introduced in detail below.

[0051] First, please refer to Figure 1 , Figure 1 A schematic structural diagram of a filter circuit provided by the present invention is shown. The filter circuit 10 includes a resonant component 11 , a coupling capacitor 12 and / or a coupling inductor 13 ; the resonant component 11 includes at least two resonant units 21 .

[0052] Part or all of the resonant units 21 are connected in parallel with a coupling capacitor 12 to form a capacitive cross-coupling circuit;

[0053] And / or some or all of the resonant units 21 are connected via a coupling inductor 13 to form an inductive coupling circuit to improve the quality factor of the filter circuit.

[0054] It should be noted that Figure 1 It is just a simple illustration of the coupling arrangement of the lower part of the resonant unit of the filter circuit in the present invention and the corresponding coupling capacitor and coupling inductor.

[0055] In this embodiment, some or all of the resonant units are connected in parallel with a coupling capacitor; and / or some or all of the resonant units are connected through a coupling inductor, so that cross-coupling can be introduced between the resonant units, increasing the transmission zero point of the filter circuit, thereby increasing suppression and improving the performance of the filter.

[0056] In this embodiment, there is no restriction on the connection relationship between the resonant component and the coupling capacitor and / or the coupling inductor, nor is there any restriction on the number of resonant units and the connection method between the resonant units. According to actual needs, capacitor cross-coupling and / or inductive coupling can be used to increase the transmission zero point of the filter circuit to adjust the quality factor.

[0057] Embodiment 1

[0058] When the filter circuit only includes resonant components and coupling capacitors, please refer to Figure 2 , Figure 2 Another structural schematic diagram of the filter circuit provided by the present invention is shown. In this embodiment, a T-type inductor structure 22 is formed between the resonant units 21 of the resonant component 11, and the filter circuit 10 also includes a first π-type capacitor structure 23, a second π-type capacitor structure 24 and a first coupling capacitor Cs.

[0059] The first π-type capacitor structure 23 is connected in series with the second π-type capacitor structure 24 via the T-type inductor structure 22 to form a series branch; and the first coupling capacitor Cs is connected in parallel with the series branch.

[0060] In this embodiment, the filter circuit includes two π-type capacitor structures, a T-type inductor structure 22 and a coupling capacitor, constructing a symmetrical π-T transformation structure, so that the above-mentioned filter circuit can effectively reduce the inductance and capacitance values ​​while ensuring the resonant frequency, thereby effectively improving the inductance Q value in the same space, increasing the capacitance density, and thus improving the circuit performance.

[0061] In one possible implementation, Figure 2 Based on the reference Figure 3 , Figure 3 Another structural schematic diagram of the filter circuit provided by the present invention is shown. In this embodiment, the filter circuit 10 also includes at least one filter unit 25, a first end of the filter unit 25 is connected to the input / output port of the filter circuit 10, and a second end of the filter unit 25 is connected to the input end of the first π-type capacitor structure 23.

[0062] In another possible implementation, when the filter circuit includes a plurality of input / output ports, in this embodiment, a filter unit may be provided corresponding to each input / output port to effectively increase the suppression of interference signals.

[0063] In one possible implementation, Figure 2 Based on the reference Figure 4 , Figure 4The circuit schematic diagram of the filter circuit provided by the present invention is shown. When the filter circuit only includes a resonant component and a coupling capacitor, the resonant component 11 may also include a common inductor L3, wherein each resonant unit 21 shares a common inductor L3 and is grounded through the common inductor L3 to form a T-type inductor structure 22.

[0064] Among them, each resonant unit shares a common inductor L3 and is grounded through the common inductor L3 to form a T-type inductor structure. Based on this structure, this embodiment can effectively overcome the problem of large inductance and capacitance values ​​of the filter circuit in the low frequency band of the prior art, and after reducing the inductance value, further improve the device performance and reduce the device cost.

[0065] In one possible implementation, Figure 4 Based on the reference Figure 5 , Figure 5 The circuit schematic diagram of the filter circuit provided by the present invention is shown. When the resonance component 11 includes a first resonance unit 31, a second resonance unit 32, and a common inductor L3, the first resonance unit 31 includes a first inductor L1 and a first capacitor C1; the second resonance unit 32 includes a second inductor L2 and a second capacitor C2.

[0066] The first end of the first capacitor C1 and the first end of the second capacitor C2 are both grounded; the second end of the first capacitor C1 is respectively connected to the first end of the first inductor L1 and the second end of the first π-type capacitor structure 23; the second end of the second capacitor C2 is respectively connected to the first end of the second inductor L2 and the second end of the second π-type capacitor structure 24; the second end of the first inductor L1 is respectively connected to the second end of the second inductor L2 and the first end of the common inductor L3; the second end of the common inductor L3 is grounded.

[0067] In this embodiment, the first inductor L1 and the first capacitor C1 constitute the resonance unit 21, and also constitute a resonance unit with the common inductor L3; similarly, the second inductor L2 and the second capacitor C2 constitute the resonance unit 21, and also constitute a resonance unit with the common inductor L3. At the same time, in the present invention, the first resonance unit 31 and the second resonance unit 32 are symmetrically arranged; the π-type capacitor structure and the resonance unit 21 are also symmetrically arranged, and the Pi-type capacitor structure can be formed by the above-mentioned symmetrical structure, which further effectively reduces the capacitance value of the required capacitor, so as to further improve the device performance and reduce the device cost.

[0068] In one possible implementation, please refer to Figure 5 In this embodiment, the first π-type capacitor structure 23 includes a third capacitor C3 and a fourth capacitor C4. The first end of the third capacitor C3 is connected to the first end of the first coupling capacitor Cs and the first end of the fourth capacitor C4 respectively; the second end of the third capacitor C3 is connected to the second end of the first capacitor C1; and the second end of the fourth capacitor C4 is grounded.

[0069] The second π-type capacitor structure 24 includes a fifth capacitor C5 and a sixth capacitor C6; the first end of the fifth capacitor C5 is connected to the second end of the first coupling capacitor Cs and the first end of the sixth capacitor C6 respectively; the second end of the fifth capacitor C5 is connected to the second end of the second capacitor C2; the second end of the sixth capacitor C6 is grounded.

[0070] Embodiment 2

[0071] When the filter circuit 10 includes a resonant component 11, a coupling capacitor 12 and a coupling inductor 13, Figure 2 Based on the reference Figure 6 , Figure 6 Another structural schematic diagram of the filter circuit provided by the present invention is shown. In this embodiment, the resonant component 11 includes a plurality of resonant units 21. Two adjacent resonant units 21 are connected via a coupling inductor 13, so that the two adjacent resonant units 21 have inductive coupling;

[0072] For any resonance unit 21 , the current resonance unit 21 is capacitively coupled with the corresponding target resonance unit via a coupling capacitor 12 ; the target resonance unit is used to represent the remaining resonance units except the resonance unit adjacent to the current resonance unit.

[0073] Wherein, any resonance unit 21 corresponds to at least one target resonance unit.

[0074] In one possible implementation, Figure 6 Based on the reference Figure 7 , Figure 7 Another structural schematic diagram of the filter circuit provided by the present invention is shown. When the resonance component 11 includes the third resonance unit 33, the fourth resonance unit 34, the fifth resonance unit 35, and the sixth resonance unit 36, in order to reduce the structure of the filter circuit 10, the filter circuit 10 in this embodiment further includes a first coupling inductor L4, a second coupling inductor L5, a third coupling inductor L6, a second coupling capacitor C7, and a third coupling capacitor C8;

[0075] The first end of the third coupling capacitor C8 is connected to the first end of the second coupling capacitor C7 and the first end of the third resonance unit 33 respectively; the second end of the third coupling capacitor C8 is connected to the second end of the sixth resonance unit 36; the second end of the second coupling capacitor C7 is connected to the second end of the fifth resonance unit 35; the second end of the third resonance unit 33 is connected to the first end of the fourth resonance unit 34 through the first coupling inductor L4; the second end of the fourth resonance unit 34 is connected to the first end of the fifth resonance unit 35 through the second coupling inductor L5; the second end of the fifth resonance unit 35 is also connected to the first end of the sixth resonance unit 36 ​​through the third coupling inductor L6.

[0076] It should be noted that in this embodiment Figure 7 The structural diagram shown is only one example. In another possible implementation, according to the connection relationship between the above-mentioned resonance units 21, taking the fourth resonance unit 34 as an example, the target resonance unit 21 corresponding to the fourth resonance unit 34 is the sixth resonance unit 36, that is, at this time, a coupling capacitor can also be set between the first end of the fourth resonance unit 34 and the second end of the sixth resonance unit 36. In order to further reduce the structure of the filter circuit, the above-mentioned coupling capacitor 12 can be omitted.

[0077] Among them, please Figure 7 Based on the reference Figure 8 , Figure 8 The schematic diagram of the corresponding filter circuit when each resonant unit is composed of a capacitor and an inductor is shown. Please continue to refer to Figure 8 In this embodiment, with respect to the capacitive coupling relationship, taking the third resonance unit 33 as an example, the target resonance unit 21 corresponding to the third resonance unit 33 is the fifth resonance unit 35 and the sixth resonance unit 36; it can be seen that the third resonance unit 33 and the fifth resonance unit 35 form a capacitive coupling through the second coupling capacitor C7; the third resonance unit 33 and the sixth resonance unit 36 ​​form a capacitive coupling through the second coupling capacitor C7.

[0078] In this embodiment, with respect to the inductive coupling relationship, the third resonant unit 33 and the fourth resonant unit 34 form inductive coupling through the first coupling inductor L4; the fourth resonant unit 34 and the fifth resonant unit 35 form inductive coupling through the second coupling inductor L5; and the fifth resonant unit 35 and the sixth resonant unit 36 ​​form inductive coupling through the third coupling inductor L6.

[0079] Based on this, this embodiment can effectively reduce the inductance and capacitance values ​​while ensuring the resonant frequency, thereby effectively improving the inductance Q value and increasing the capacitance density in the same space, thereby solving the problem of complex filtering circuits and low circuit integration in the prior art, and improving the performance of the filter at a low cost.

[0080] Furthermore, this embodiment also provides a filter chip 100, Figure 7 Based on the reference Fig. 9 , Fig. 9 The schematic diagram of the structure of the filter chip provided by the present invention is shown. The filter chip 100 includes at least a first metal grounding layer 103, an inductor dielectric layer 102, a capacitor dielectric layer 101 and a second metal grounding layer 104 from bottom to top, wherein the capacitor dielectric layer 101 is made of a high dielectric constant material.

[0081] In this embodiment, the inductor dielectric layer 102 is composed of an inductor dielectric and a metal through hole. In a possible implementation method, the aperture and height of the metal through hole can be adjusted to adjust the inductor parts of the filter circuit in the above embodiment, for example, the inductor parts in each resonant unit and / or the coupled inductor 13 part.

[0082] In this embodiment, when each capacitor part under the filter circuit, such as each coupling capacitor, adopts a parallel plate capacitor, correspondingly, the capacitor dielectric layer 101 can be composed of a capacitor dielectric with a high dielectric constant and a low loss factor at a high frequency such as 40 GHz.

[0083] In this embodiment, the outermost portions of the first metal grounding layer 103 and the second metal grounding layer 104 may be connected via through holes to achieve electromagnetic shielding and reduce interference and stray.

[0084] Embodiment 3

[0085] In this embodiment, on the basis of the second embodiment, at least one resonator chip 200 is additionally provided.

[0086] The above scheme will be described in detail below.

[0087] In this embodiment, the filter circuit further includes at least one resonator chip, and the resonator chip is arranged in parallel at the input / output port of the filter circuit.

[0088] In one possible implementation, Figure 7 Based on the reference Fig.10 , Fig.10 Another structural schematic diagram of the filter circuit provided by the present invention is shown. When the filter circuit 10 includes a first resonator chip 201, a second resonator chip 202 and a third resonator chip 203, and the filter circuit 10 includes a first input / output port and a second input / output port, a first end of the first resonator chip 201 is connected to the first input / output port of the filter circuit 10 and a first end of the second resonator chip 202; a second end of the first resonator chip 201 is grounded; a second end of the second resonator chip 202 is connected to a first end of the third resonator chip 203 and a second input / output port of the filter circuit 10; and a second end of the third resonator chip 203 is grounded.

[0089] In this embodiment, the above-mentioned resonator chips include but are not limited to IPD / SAW / BAW / FBAR, etc.

[0090] For further information, please Figure 7 Based on the reference Fig.11 , Fig.11Another structural schematic diagram of the filter chip provided by the present invention is shown, and the filter chip 100 includes at least from bottom to top a resonator chip layer 105, a first metal grounding layer 103, an inductor dielectric layer 102, a capacitor dielectric layer 101 and a second metal grounding layer 104, wherein the capacitor dielectric layer 101 is composed of a high dielectric constant material. The resonator chip 200 layer includes a plurality of resonator chips 200, and each resonator chip 200 is connected to the first metal grounding layer 103 through a metal pin (input / output pin), and is fixed on the first metal grounding layer 103 through plastic packaging. Among them, the first metal grounding layer 103 can effectively reduce the mutual interference between the resonator chip 200 and the main filter structure in the filter circuit 10, and further improve the suppression performance of the filter circuit 10.

[0091] In addition, this embodiment also provides the experimental results corresponding to the above three embodiments, please refer to Fig.12 , Fig.13 , Fig.14 as well as Fig.15 .

[0092] Please refer to Fig.12 and Fig.13 , Fig.12 This is the simulation result before adding capacitive coupling. Fig.13 This is the simulation result of the filter circuit 10 corresponding to the first embodiment. It can be seen that before the coupling capacitor 12 is added, there is no transmission zero point at the near end of the passband of the corresponding filter circuit 10, and the suppression of the adjacent frequency band is insufficient. After the coupling capacitor 12 is added to the present embodiment, a transmission zero point Z1 and Z2 are formed on both sides of the passband, thereby increasing the suppression.

[0093] Please refer to Fig.14 , Fig.14 This is the simulation result of the filter circuit corresponding to the above-mentioned embodiment 2. The embodiment 2 provided by the present invention can form nearly 40dB suppression at 150MHz out of band and can achieve a bandwidth of more than 500MHz.

[0094] Please refer to Fig.15 , Fig.15 This is the simulation result of the filter circuit corresponding to the above-mentioned embodiment three. When working in the millimeter wave frequency band, the capacitor and inductor are small enough. At this time, a low dielectric constant capacitor medium can be used specifically to enable the circuit to work in the millimeter wave frequency band. However, the chip-scale circuit often does not meet the requirements at the 30GHz Q value, the adjacent frequency bands are not suppressed enough, and the quality of the communication system is too low. Currently, there is no chip-level filter circuit 10 with a higher Q value that can meet the communication requirements in this frequency band. Embodiment three provided by the present invention improves circuit performance by loading an acoustic resonator that works in millimeter waves. Based on this, the upper and lower metal grounding layers in this embodiment can also effectively reduce the mutual interference between the chip and the main circuit, and reduce the difficulty and volume of integration.

[0095] In summary, the filter circuit 10 and filter provided in this embodiment can effectively reduce the inductance and capacitance values ​​while ensuring the resonant frequency, thereby effectively improving the inductance Q value and increasing the capacitance density in the same space, thereby solving the problem of complex filter circuit 10 and low circuit integration in the prior art, and improving the performance of the filter at a low cost.

[0096] Based on the above concept, in one embodiment, the present invention also provides a radio frequency front-end module, including the filter circuit 10 provided in the above embodiment, which can introduce cross-coupling between the resonant units 21, increase the transmission zero point of the filter circuit 10, thereby increasing suppression, improving the performance of the filter, and effectively reducing the inductance and capacitance values ​​while ensuring the resonant frequency, thereby effectively improving the inductance Q value and increasing the capacitance density in the same space.

[0097] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0098] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A filter circuit, characterized in that: The filtering circuit includes a resonant component, a coupling capacitor and / or a coupling inductor; the resonant component includes at least two resonant units; Part or all of the resonant units are connected in parallel with a coupling capacitor to form a capacitive cross-coupling circuit; And / or part or all of the resonant units are connected via a coupling inductor to form an inductive coupling circuit to improve the quality factor of the filter circuit.

2. The filter circuit according to claim 1, characterized in that: When the resonant component constitutes a T-type inductor structure, the filter circuit also includes a first π-type capacitor structure, a second π-type capacitor structure and a first coupling capacitor. The first π-type capacitor structure is connected in series with the second π-type capacitor structure through the T-type inductor structure to form a series branch; the first coupling capacitor is connected in parallel with the series branch.

3. The filter circuit according to claim 2, characterized in that: The filter circuit further includes at least one filter unit, a first end of the filter unit is connected to an input / output port of the filter circuit, and a second end of the filter unit is connected to an input end of the first π-type capacitor structure.

4. The filter circuit according to claim 2, characterized in that: When the filter circuit includes a resonant component and a coupling capacitor, the resonant component also includes a common inductor, wherein the resonant units are arranged in parallel and are all grounded through the common inductor to form a T-type inductor structure.

5. The filter circuit according to claim 4, characterized in that: When the resonant component includes a first resonant unit, a second resonant unit, and a common inductor, the first resonant unit includes a first inductor and a first capacitor; the second resonant unit includes a second inductor and a second capacitor; The first end of the first capacitor and the first end of the second capacitor are both grounded; the second end of the first capacitor is respectively connected to the first end of the first inductor and the second end of the first π-type capacitor structure; the second end of the second capacitor is respectively connected to the first end of the second inductor and the second end of the second π-type capacitor structure; the second end of the first inductor is respectively connected to the second end of the second inductor and the first end of the common inductor; and the second end of the common inductor is grounded.

6. The filter circuit according to claim 5, characterized in that: The first π-type capacitor structure includes a third capacitor and a fourth capacitor, wherein the first end of the third capacitor is connected to the first end of the first coupling capacitor and the first end of the fourth capacitor respectively; the second end of the third capacitor is connected to the second end of the first capacitor; and the second end of the fourth capacitor is grounded; The second π-type capacitor structure includes a fifth capacitor and a sixth capacitor; the first end of the fifth capacitor is respectively connected to the second end of the first coupling capacitor and the first end of the sixth capacitor; the second end of the fifth capacitor is connected to the second end of the second capacitor; and the second end of the sixth capacitor is grounded.

7. The filter circuit according to claim 1, characterized in that: When the filter circuit includes a resonant component, a coupling capacitor and a coupling inductor, and the resonant component includes a plurality of resonant units, Two adjacent resonant units are connected via a coupling inductor, so that the two adjacent resonant units have inductive coupling; For any resonance unit, the current resonance unit is capacitively coupled with the corresponding target resonance unit through a coupling capacitor; the target resonance unit is used to represent the remaining resonance units except the resonance unit adjacent to the current resonance unit; Wherein, any resonance unit corresponds to at least one target resonance unit.

8. The filter circuit according to claim 7, characterized in that: When the resonant component includes a third resonant unit, a fourth resonant unit, a fifth resonant unit, and a sixth resonant unit, the filter circuit further includes a first coupling inductor, a second coupling inductor, a third coupling inductor, a second coupling capacitor, and a third coupling capacitor; The first end of the third coupling capacitor is connected to the first end of the second coupling capacitor and the first end of the third resonance unit respectively; the second end of the third coupling capacitor is connected to the second end of the sixth resonance unit; the second end of the second coupling capacitor is connected to the second end of the fifth resonance unit; the second end of the third resonance unit is connected to the first end of the fourth resonance unit through the first coupling inductor; the second end of the fourth resonance unit is connected to the first end of the fifth resonance unit through the second coupling inductor; the second end of the fifth resonance unit is also connected to the first end of the sixth resonance unit through the third coupling inductor.

9. The filter circuit according to claim 8, characterized in that: The filter circuit further includes at least one resonator chip, and the resonator chip is arranged in parallel at an input / output port of the filter circuit.

10. A radio frequency front-end module, characterized in that: The filter circuit comprises the filter circuit described in any one of claims 1 to 9.

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