Filter, radio frequency front-end chip and radio frequency front-end module

Abstract

The invention provides a filter, a radio frequency front-end chip and a radio frequency front-end module. The filter comprises an input terminal, an output terminal, a series arm resonator group, a parallel arm resonator group and a longitudinal coupling surface acoustic wave resonator. Wherein the longitudinal coupling surface acoustic wave resonator and the series arm resonator group are both connected to a series path between the input terminal and the output terminal, a first end of the parallel arm resonator group is connected between the longitudinal coupling surface acoustic wave resonator and the output terminal, and a second end of the parallel arm resonator group is connected with the grounding terminal. Through the position adjustment of the parallel arm resonator group, the passband loss can be reduced when the filter is used in cooperation with other filters.

Description

Technical Field

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

[0002] Filters are commonly used electronic devices in radio frequency circuits and can be used to filter out specific frequencies or signals other than specific frequencies in a signal. Some filters on the market have different considerations at the transmitting and receiving ends, and will use a hybrid filter that combines a longitudinally coupled surface acoustic wave resonator with a ladder structure resonator group. However, in actual applications, it is found that the absolute value of the return loss of this hybrid filter in the high frequency band is large, so that when a high-frequency filter is used in conjunction with this hybrid filter, the passband loss will increase. Summary of the invention

[0003] The main purpose of the present application is to provide a filter, a radio frequency front-end chip and a radio frequency front-end module, aiming to solve the problem that the passband loss will increase when the filter is used in conjunction with other filters.

[0004] In a first aspect, the present application provides a filter, the filter comprising an input terminal, an output terminal, a series arm resonator group, a parallel arm resonator group and a longitudinally coupled surface acoustic wave resonator, wherein:

[0005] The longitudinally coupled surface acoustic wave resonator and the series arm resonator group are both connected to a series path between the input terminal and the output terminal;

[0006] A first end of the parallel arm resonator group is connected between the longitudinally coupled surface acoustic wave resonator and the output terminal, and a second end of the parallel arm resonator group is connected to a ground terminal.

[0007] In a second aspect, an embodiment of the present application further provides a radio frequency receiving module, comprising a plurality of receiving filters, at least two of the plurality of receiving filters being configured to implement carrier aggregation of radio frequency signals of different frequency bands;

[0008] Among them, at least one of the at least two receiving filters is configured as a filter as described in any one of the embodiments of the present application.

[0009] In a third aspect, an embodiment of the present application further provides a radio frequency front-end module, comprising a plurality of filters, at least two of the plurality of filters being configured to implement carrier aggregation of radio frequency signals of different frequency bands;

[0010] Wherein, at least one of the at least two filters is configured as a filter as described in any one of the embodiments of the present application.

[0011] The present application provides a filter, a radio frequency front-end chip and a radio frequency front-end module, wherein the filter includes an input terminal, an output terminal, a series arm resonator group, a parallel arm resonator group and a longitudinally coupled surface acoustic wave resonator. The longitudinally coupled surface acoustic wave resonator and the series arm resonator group are both connected to the series path between the input terminal and the output terminal, the first end of the parallel arm resonator group is connected between the longitudinally coupled surface acoustic wave resonator and the output terminal, and the second end of the parallel arm resonator group is connected to the ground terminal. By adjusting the position of the parallel arm resonator group in the filter to the output end side of the longitudinally coupled surface acoustic wave resonator, the capacitance to ground at the input end of the filter can be reduced, thereby reducing the absolute value of the return loss in the high frequency band, so that the passband loss can be reduced when used in conjunction with other filters. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 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.

[0013] Figure 1 and Figure 2 A circuit diagram of an implementation of a filter provided in an embodiment of the present application;

[0014] Figure 3 A schematic diagram showing a comparison of absolute values ​​of return losses of filters provided in an embodiment of the present application;

[0015] Figure 4 A schematic diagram of a comparison of the Smith chart of the filter provided in the embodiment of the present application;

[0016] Figure 5 A schematic diagram comparing insertion losses of other filters used in conjunction with the filter provided in an embodiment of the present application;

[0017] Figure 6 A circuit diagram of another implementation of the filter provided in an embodiment of the present application;

[0018] Figure 7 A circuit diagram of another implementation of the filter provided in an embodiment of the present application;

[0019] Figure 8 A circuit diagram of another implementation of the filter provided in an embodiment of the present application;

[0020] Fig. 9 A circuit diagram of another implementation of the filter provided in an embodiment of the present application;

[0021] Fig.10 A circuit diagram of another implementation of the filter provided in an embodiment of the present application;

[0022] Fig.11 A circuit diagram of another implementation of the filter provided in an embodiment of the present application;

[0023] Fig.12 A circuit diagram of another implementation of the filter provided in an embodiment of the present application;

[0024] Fig.13 A circuit diagram of another implementation of the filter provided in an embodiment of the present application;

[0025] Fig.14 A schematic diagram of an implementation of a radio frequency receiving module provided in an embodiment of the present application;

[0026] Fig.15 A circuit diagram of another implementation of the radio frequency receiving module provided in an embodiment of the present application;

[0027] Fig.16 A schematic diagram of a scenario of an implementation of a radio frequency receiving module provided in an embodiment of the present application;

[0028] Fig.17 A circuit diagram of another implementation of the radio frequency receiving module provided in an embodiment of the present application;

[0029] Fig.18 A circuit diagram of another implementation of the radio frequency receiving module provided in an embodiment of the present application;

[0030] Fig.19 A schematic diagram of an implementation of a radio frequency front-end module provided in an embodiment of the present application;

[0031] Fig. 20 Another schematic diagram of an implementation of the RF front-end module provided in an embodiment of the present application

[0032] Fig.21 Another schematic diagram of an implementation of a radio frequency front-end module provided in an embodiment of the present application;

[0033] Fig. 22 Another schematic diagram of an implementation of the RF front-end module provided in an embodiment of the present application.

[0034] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0035] 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.

[0036] 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.

[0037] Please refer to Figure 1 and Figure 2 , Figure 1 and Figure 2 A circuit diagram of an implementation of a filter provided in an embodiment of the present application.

[0038] like Figure 1 and Figure 2 As shown, the filter 100 includes an input terminal Input, an output terminal Output, a series arm resonator group 110 , a parallel arm resonator group 120 and a longitudinally coupled surface acoustic wave resonator 130 .

[0039] The longitudinally coupled surface acoustic wave resonator 130 and the series arm resonator group 110 are both connected to the series path between the input terminal Input and the output terminal Output. The first end of the parallel arm resonator group 120 is connected between the longitudinally coupled surface acoustic wave resonator 130 and the output terminal Output, and the second end of the parallel arm resonator group 120 is connected to the ground terminal GND.

[0040] It should be noted that, in the series path between the input terminal Input and the output terminal Output, the input end of the longitudinally coupled surface acoustic wave resonator 130 can be connected to the input terminal Input, and the series arm resonator group 110 can be connected between the output end of the longitudinally coupled surface acoustic wave resonator 130 and the output terminal Output. The longitudinally coupled surface acoustic wave resonator 130 can specifically be a resonator structure in which at least two interdigitated electrodes (also referred to as IDT electrodes) are arranged between two reflectors, for example, it can be a dual-mode surface acoustic wave filter (also referred to as DMS), a multi-mode surface acoustic wave filter, etc., which is not limited in the present application. Figure 1 As shown, the first end of the parallel arm resonator group 120 can be connected between the output end of the longitudinally coupled surface acoustic wave resonator 130 and the input end of the series arm resonator group 110. Figure 2 As shown, the first end of the parallel arm resonator group 120 may also be connected between the output end of the series arm resonator group 110 and the output terminal Output.

[0041] The filter 100 may be a receiving filter or a transmitting filter, preferably a receiving filter. The series arm resonator group 110 may be one or more. When the series arm resonator group 110 is multiple, the multiple series arm resonator groups 110 may be connected in series to the path between the longitudinally coupled surface acoustic wave resonator 130 and the output terminal Output. The parallel arm resonator group 120 may also be one or more. When the parallel arm resonator group 120 is multiple, the multiple parallel arm resonator groups 120 may be connected in parallel to the path between the longitudinally coupled surface acoustic wave resonator 130 and the output terminal Output.

[0042] The number of the plurality of parallel arm resonator groups 120 and the number of the plurality of series arm resonator groups 110 may be the same or different. For example, the parallel arm resonator groups 120 and the series arm resonator groups 110 may be connected in a one-to-one correspondence, or may be connected in a one-to-many or many-to-one manner. By longitudinally coupling the acoustic wave propagation mechanism inside the surface acoustic wave resonator 130, signal isolation can be formed between the input terminal Input and the output terminal Output.

[0043] A parallel arm resonator group is connected between the traditional filter and the input terminal Input. For example, one end of a part of the parallel arm resonator group is connected between the input terminal Input and the longitudinally coupled surface acoustic wave resonator 130, and the other end is connected to the ground terminal. Its function can be approximately regarded as a capacitor, which will cause the absolute value of the return loss of the filter 100 in the high frequency band to increase.

[0044] In the embodiment of the present application, the parallel arm resonator groups 120 are all connected between the longitudinally coupled surface acoustic wave resonator 130 and the output terminal Output, which can reduce the capacitance of the input terminal Input to the ground, so that the capacitive impedance at the input terminal Input of the filter 100 matches the characteristic impedance of the transmission line, thereby reducing the absolute value of the return loss of the filter 100 in the high frequency band, so that the filter 100 can reduce the passband loss when used in conjunction with other filters, such as when realizing carrier aggregation of radio frequency signals in different frequency bands.

[0045] For example, Figure 3 As shown, Figure 3A schematic diagram for comparing the absolute values ​​of the return loss of the filter provided in the embodiment of the present application. Among them, curve 11 (dashed line) is used to characterize the absolute value of the return loss of the traditional filter in the passband, curve 12 (solid line) is used to characterize the absolute value of the return loss of the filter 100 in the embodiment of the present application in the passband, and area 13 is used to characterize the high frequency band, for example, from 2.3 GHz to 2.69 GHz. It can be seen that in the high frequency band such as the frequency band range shown in area 13, the absolute value of the return loss shown in curve 12 is obviously smaller than that of curve 11. Therefore, the filter 100 provided in the embodiment of the present application has a lower absolute value of the return loss in the high frequency band.

[0046] For example, Figure 4 As shown, Figure 4 A comparative schematic diagram of the Smith chart of the filter provided in the embodiment of the present application. Among them, curve 21 (dashed line) is used to characterize the impedance of the traditional filter in the set high frequency band, and curve 12 (solid line) is used to characterize the impedance of the filter 100 in the embodiment of the present application in the set high frequency band. The high frequency band is set to 2.3GHz to 2.69GHz, for example. It can be seen that the closer the impedance is to the open circuit point, the better the filter performance. Therefore, compared with curve 21, the impedance shown in curve 22 is obviously closer to the open circuit point, which shows that the filter 100 in the embodiment of the present application has better circuit impedance matching in the set high frequency band, which can minimize signal reflection and transmission loss, and ensure the effective transmission of RF signals.

[0047] For example, Figure 5 As shown, Figure 5 A comparative schematic diagram of the insertion loss of other filters used in conjunction with the filter provided in the embodiment of the present application. Wherein, curve 31 (dashed line) is used to characterize the insertion loss of the other filter when the traditional filter is used in conjunction with other filters in a set high frequency band, and curve 32 (solid line) is used to characterize the insertion loss of the other filter when the filter 100 of the embodiment of the present application is used in conjunction with other filters in a set high frequency band. The set high frequency band is, for example, 2.3 GHz to 2.75 GHz. It can be seen that compared with curve 31, the absolute value of the insertion loss shown in curve 32 is smaller, which means that when the filter 100 of the embodiment of the present application is used in conjunction with other filters in a set high frequency band, the insertion loss of other filters is lower, thereby being able to reduce the overall passband loss generated.

[0048] Specifically, as shown in the following table:

[0049]

[0050] in, Figure 5The vertical line m65 in FIG. 1 is used to mark the insertion loss corresponding to curves 31 and 32 in the 2.495 GHz signal scenario. It can be seen that the insertion loss corresponding to curve 31 is -4.063 dB, and the insertion loss corresponding to curve 32 is -3.739 dB. Compared with curve 31, the absolute value of the insertion loss shown in curve 32 is smaller.

[0051] in, Figure 5 The vertical line m66 in is used to mark the insertion loss corresponding to curves 31 and 32 in the 2.690GHz signal scenario. It can be seen that the insertion loss corresponding to curve 31 is -3.929dB, and the insertion loss corresponding to curve 32 is -3.523dB. Compared with curve 31, the absolute value of the insertion loss shown in curve 32 is smaller. It can be shown that when the filter 100 of the embodiment of the present application is used in conjunction with other filters in a set high frequency band, the insertion loss of other filters is significantly reduced, thereby reducing the overall passband loss.

[0052] In one embodiment, if Figure 6 As shown, the series arm resonator group 110 includes a first series arm resonator group 111 connected to the output end of the longitudinally coupled surface acoustic wave resonator 130. The parallel arm resonator group 120 includes a first parallel arm resonator group 121, a first end of the first parallel arm resonator group 121 is connected between the output end of the longitudinally coupled surface acoustic wave resonator 130 and the input end of the first series arm resonator group 111, and a second end of the first parallel arm resonator group 121 is connected to the ground terminal GND.

[0053] It should be noted that the first end of the first parallel arm resonator group 121 is connected to the path between the output end of the longitudinally coupled surface acoustic wave resonator 130 and the input end of the first series arm resonator group 111, which can reduce the signal amplitude variation within the passband, thereby improving the out-of-band rectangularity of the filter 100 to ensure the clarity of the RF signal and the stability of the filter 100.

[0054] In one embodiment, the first parallel arm resonator group 121 includes a plurality of first resonators connected in parallel. It should be noted that when the first parallel arm resonator group 121 includes a plurality of first resonators connected in parallel, the attenuation capability of the filter 100 for signals in the region above the passband frequency can be enhanced, thereby improving the out-of-band signal suppression capability of the filter 100 on the high-frequency side, so that the filter 100 has better performance at a specific frequency.

[0055] In one embodiment, if Figure 7As shown, the parallel arm resonator group 120 also includes at least one second parallel arm resonator group 122, a first end of the second parallel arm resonator group 122 is connected between the output end of the first series arm resonator group 111 and the output terminal Output, and a second end of the second parallel arm resonator group 122 is connected to the ground terminal GND.

[0056] It should be noted that Figure 7 The second parallel arm resonator group 122 shown is one, and in actual applications, there may be multiple second parallel arm resonator groups 122. The first end of each second parallel arm resonator group 122 is connected to the path between the output end of the first series arm resonator group 111 and the output terminal Output. The specific number of the second parallel arm resonator groups 122 can be set according to actual conditions, and the embodiment of the present application does not specifically limit this.

[0057] In one embodiment, if Figure 8 As shown, the series arm resonator group 110 further includes at least one second series arm resonator group 112, and the path between two adjacent second series arm resonator groups 112 is connected to the first end of at least one second parallel arm resonator group 122. The path between the second series arm resonator group 112 adjacent to the first series arm resonator group 111 and the first series arm resonator group 111 is connected to the first end of at least one second parallel arm resonator group 122.

[0058] It should be noted that Figure 8 The second series arm resonator group 112 shown is one, and in actual applications, the second series arm resonator group 112 can be multiple. When the second series arm resonator group 112 is one, the path between the second series arm resonator group 112 and the first series arm resonator group 111 is connected to the first end of at least one second parallel arm resonator group 122. When the second series arm resonator group 112 is multiple, the path between two adjacent second series arm resonator groups 112 is connected to the first end of at least one second parallel arm resonator group 122, and the second series arm resonator group 112 and at least one second parallel arm resonator group 122 are alternately placed, thereby providing a specific frequency response characteristic and providing a signal transmission efficiency within a specific frequency range.

[0059] In one embodiment, if Fig. 9 As shown, there are multiple second series arm resonator groups 112 and multiple second parallel arm resonator groups 122, and each second series arm resonator group 112 and each second parallel arm resonator group 122 are alternately arranged one by one to form a resonant unit of a ladder structure. By alternately placing multiple second series arm resonator groups 112 and multiple second parallel arm resonator groups 122 between the output end of the longitudinally coupled surface acoustic wave resonator 130 and the input terminal Input in a ladder structure, the best out-of-band suppression performance is obtained.

[0060] It can be understood that at least one of the first series arm resonator group 111, the second parallel arm resonator group 122 and the first parallel arm resonator group 121 includes at least one resonator. That is to say, the first series arm resonator group 111, the second parallel arm resonator group 122 and the first parallel arm resonator group 121 can each include one resonator, or can each include multiple resonators, or some resonator groups can include one resonator while other parts of the resonator group include multiple resonators. Therefore, the number of resonators in the first series arm resonator group 111, the second parallel arm resonator group 122 and the first parallel arm resonator group 121 can be the same or different. Similarly, the second series arm resonator group 112 can also include at least one resonator.

[0061] In one embodiment, if Fig.10 As shown, the filter 100 further includes an inductor unit 140 and at least one third series arm resonator group 150. A first end of the inductor unit 140 is connected to the input terminal Input, and a second end of the inductor unit 140 is connected to the ground terminal GND. Each third series arm resonator group 150 is connected in series between the input terminal Input and the input end of the longitudinally coupled surface acoustic wave resonator 130.

[0062] The third series arm resonator group 150 includes at least one resonator. The inductor unit 140 includes at least one inductor. When there are multiple inductors, the multiple inductors are connected in parallel. It should be noted that the inductor unit 140 and at least one third series arm resonator group 150 can form a phase shifter, wherein the resonant frequency of at least one third series arm resonator group 150 should be set to the signal frequency of the desired phase shift, thereby changing the phase of the input signal.

[0063] In one embodiment, the third series arm resonator group 150 includes a plurality of second resonators connected in cascade. By connecting a plurality of resonators in cascade in the third series arm resonator group 150, a steeper roll-off of the filter 100 can be created in the high frequency band, thereby optimizing the circuit impedance in the high frequency band and improving the performance of the filter 100.

[0064] In one embodiment, the longitudinally coupled surface acoustic wave resonator 130 includes a piezoelectric substrate and at least two interdigital electrodes arranged on the piezoelectric substrate. Each interdigital electrode is composed of two groups of parallel metal lines, and the lines are arranged alternately to form a pattern similar to a finger crossing. The at least two interdigital electrodes are, for example, 2, 3, 5 or more interdigital electrodes. The connection mode of the longitudinally coupled surface acoustic wave resonator 130 can be set according to actual conditions. For example, when the number of interdigital electrodes is 5, the longitudinally coupled surface acoustic wave resonator 130 can be a two-input and three-output connection mode, or a three-input and two-output connection mode.

[0065] It should be noted that the interdigital electrodes can form an interdigital transducer. In the longitudinally coupled surface acoustic wave resonator 130, the interdigital electrodes are arranged at intervals in the direction of acoustic wave propagation to form a longitudinal coupling structure. Through the longitudinal coupling structure, the quality factor of the resonator itself can be effectively improved, thereby improving its frequency selectivity and stability.

[0066] In one embodiment, if Fig.11 As shown, the longitudinally coupled surface acoustic wave resonator 130 includes a first longitudinally coupled surface acoustic wave resonator 131 and a second longitudinally coupled surface acoustic wave resonator 132 connected in parallel. When the first longitudinally coupled surface acoustic wave resonator 131 and the second longitudinally coupled surface acoustic wave resonator 132 are connected in parallel, their frequency responses will be superimposed to a certain extent, and the impedance matching of the entire filter 100 can be improved, signal reflection can be reduced, and the effective bandwidth can be increased.

[0067] In one embodiment, if Fig.12 As shown, the longitudinally coupled surface acoustic wave resonator 130 further includes a third longitudinally coupled surface acoustic wave resonator 133 and a fourth longitudinally coupled surface acoustic wave resonator 134. The third longitudinally coupled surface acoustic wave resonator 133 is connected in series with the first longitudinally coupled surface acoustic wave resonator 131, and the fourth longitudinally coupled surface acoustic wave resonator 134 is connected in series with the second longitudinally coupled surface acoustic wave resonator 132. The input end of the first longitudinally coupled surface acoustic wave resonator 131 is connected to the input end of the second longitudinally coupled surface acoustic wave resonator 132, and the output end of the third longitudinally coupled surface acoustic wave resonator 133 is connected to the output end of the fourth longitudinally coupled surface acoustic wave resonator 134.

[0068] It should be noted that by arranging the first longitudinally coupled surface acoustic wave resonator 131, the second longitudinally coupled surface acoustic wave resonator 132, the third longitudinally coupled surface acoustic wave resonator 133 and the fourth longitudinally coupled surface acoustic wave resonator 134 in series and parallel combination, the quality factor of the filter 100 can be improved and the insertion loss can be reduced.

[0069] For example, Fig.13As shown, the filter 100 includes an input terminal Input, an output terminal Output, a longitudinally coupled surface acoustic wave resonator 130, an inductor unit 140 and a third series arm resonator group 150, and also includes a first series arm resonator group 111, a first parallel arm resonator group 121, a second series arm resonator group 112 and a second parallel arm resonator group 122. Among them, the first series arm resonator group 111 is connected to the output end of the longitudinally coupled surface acoustic wave resonator 130. The first end of the first parallel arm resonator group 121 is connected between the output end of the longitudinally coupled surface acoustic wave resonator 130 and the input end of the first series arm resonator group 111, and the second end of the first parallel arm resonator group 121 is connected to the ground terminal GND. The first end of the second parallel arm resonator group 122 is connected between the output end of the first series arm resonator group 111 and the output terminal Output, and the second end of the second parallel arm resonator group 122 is connected to the ground terminal GND. The first end of the inductor unit 140 is connected to the input terminal Input, and the second end of the inductor unit 140 is connected to the ground terminal GND. The third series arm resonator group 150 is connected between the input terminal Input and the input end of the longitudinally coupled surface acoustic wave resonator 130. The first series arm resonator group 111, the first parallel arm resonator group 121, the second series arm resonator group 112, the second parallel arm resonator group 122 and the third series arm resonator group 150 can each include a resonator.

[0070] The filter 100 described in the above embodiment includes an input terminal Input, an output terminal Output, a series arm resonator group 110, a parallel arm resonator group 120 and a longitudinally coupled surface acoustic wave resonator 130. The longitudinally coupled surface acoustic wave resonator 130 and the series arm resonator group 110 are both connected to the series path between the input terminal Input and the output terminal Output, the first end of the parallel arm resonator group 120 is connected between the longitudinally coupled surface acoustic wave resonator 130 and the output terminal Output, and the second end of the parallel arm resonator group 120 is connected to the ground terminal GND. By adjusting the position of the parallel arm resonator group 120 in the filter 100 to the output end side of the longitudinally coupled surface acoustic wave resonator 130, the capacitance to ground at the input end of the filter 100 can be reduced, so that the capacitive impedance at the input terminal Input of the filter 100 matches the characteristic impedance of the transmission line, thereby reducing the absolute value of the return loss in the high frequency band, so that the passband loss can be reduced when used in conjunction with other filters 100.

[0071] It should be noted that the connection method between the parallel arm resonator group 120 and the inductor 140 and the ground terminal GND shown in the figure is only an example, wherein the connection method between the longitudinally coupled surface acoustic wave resonator 130 and the ground terminal GND is not shown. The parallel arm resonator group 120, the inductor 140 and the longitudinally coupled surface acoustic wave resonator 130 can be connected to a common ground on the piezoelectric substrate, or can be partially connected to a common ground, which is not limited in the present application.

[0072] Please refer to Fig.14 , Fig.14 A schematic diagram of an implementation of a radio frequency receiving module provided in an embodiment of the present application.

[0073] like Fig.14 As shown, the RF receiving module 200 includes a plurality of receiving filters 210, and at least two receiving filters 210 of the plurality of receiving filters 210 are configured to implement carrier aggregation of RF signals of different frequency bands. Among them, at least one of the at least two receiving filters 210 is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100.

[0074] The RF receiving module 200 can be used to receive RF signals and convert the RF signals into baseband signals. There are at least two receiving filters 210 in the RF receiving module 200, and at least two receiving filters 210 are configured to achieve carrier aggregation of RF signals in different frequency bands, so that the RF receiving module 200 allows multiple carriers on multiple frequency bands to be used simultaneously to increase data transmission rate and system capacity.

[0075] It should be noted that the filter in this embodiment and the following text may refer to a filter chip including a single filter, or may refer to a filter chip integrating multiple filters.

[0076] In one embodiment, if Fig.15 As shown, the RF receiving module 200 further includes a switch unit 220 , a first port of the switch unit 220 is used to connect to the antenna, and a second port of the switch unit 220 is respectively connected to the input terminal of each of the receiving filters 210 .

[0077] The antenna may be a multi-band or multi-port antenna, or multiple antennas may be used to support different frequency bands. The switch unit 220 may be used to switch between different RF paths and select a suitable receiving path to implement various modes such as reception, multi-band operation, carrier aggregation, etc. The switch unit 220 may include a field effect transistor (FET) switch, a PIN diode switch, a resonator switch, etc.

[0078] In one embodiment, if Fig.15As shown, the RF receiving module 200 further includes a low noise amplifier 230 , and the low noise amplifier 230 is connected to the output terminal of each of the receiving filters 210 .

[0079] There may be one or more low noise amplifiers 230. When there are multiple low noise amplifiers 230, they may be connected one-to-one with multiple receiving filters 210. The low noise amplifier 230 is used to provide sufficient gain when receiving a signal while minimizing the noise in the signal, thereby improving the overall sensitivity of the RF receiving module 300.

[0080] For example, Fig.16 As shown, the receiving filter A and the receiving filter C in the receiving filter 210 are configured to implement carrier aggregation of radio frequency signals in different frequency bands, and at least one of the receiving filter A and the receiving filter C is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100. When implementing carrier aggregation of RF signals Sig1 and Sig2 of different frequency bands, the switch unit 220 selects to connect the receiving filter A in multiple RF paths to receive the RF signal Sig1, and selects to connect the receiving filter C to receive the RF signal Sig2. After the receiving filter A and the receiving filter C process the RF signal Sig1 and the RF signal Sig2 respectively, they are output to the low noise amplifier 230. The low noise amplifier 230 amplifies the RF signal Sig1 and the RF signal Sig2.

[0081] In one embodiment, if Fig.17 As shown, at least two of the receiving filters 210 include a first receiving filter 211 and a second receiving filter 212. The operating frequency band of the first receiving filter 211 is higher than the operating frequency band of the second filter 212. The second filter 212 is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100, wherein the first receiving filter 211 and the second receiving filter 212 are configured to implement carrier aggregation of radio frequency signals in different frequency bands.

[0082] It should be noted that when the operating frequency band of the first receiving filter 211 is higher than the operating frequency band of the second filter 212, if the second filter 212 is configured as in the embodiment of the present application, Figure 1-2 , Figure 6-13The filter 100, that is, the second filter 212 with a lower working frequency band for improving carrier aggregation requirements, can more significantly reduce the absolute value of the return loss of the second filter 212 in the high frequency band, so that when the first receiving filter 211 and the second receiving filter 212 are used in conjunction, the passband insertion loss of the first filter 211 in the RF receiving module 200 can be more significantly reduced.

[0083] It can be understood that the first receiving filter 211 can also be configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100 described above. In the embodiment of the present application, both the first receiving filter 211 and the second receiving filter 212 are configured as follows Figure 1-2 , Figure 6-13 The filter 100 can more significantly achieve the effect of reducing the passband loss of the RF receiving module 200.

[0084] In one embodiment, if Fig.18 As shown, the at least two receiving filters 210 include a target receiving filter. The target receiving filter includes a first filtering unit 2101 and a second filtering unit 2102. The first filtering unit 2101 and the second filtering unit 2102 are configured to implement carrier aggregation of radio frequency signals in different frequency bands. At least one of the first filtering unit 2101 and the second filtering unit 2102 is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100.

[0085] The target receiving filter and at least one other receiving filter 210 are configured to achieve carrier aggregation of radio frequency signals in different frequency bands. By improving at least one of the first filtering unit 2101 and the second filtering unit 2102, the capacitance to ground at the input end of the target receiving filter can be reduced, so that the capacitive impedance at the input end of the target receiving filter matches the characteristic impedance of the transmission line, thereby reducing the absolute value of the return loss in the high frequency band, so that when used in conjunction with at least one other receiving filter 210, the passband loss generated by the radio frequency receiving module 200 can be reduced.

[0086] In one embodiment, the operating frequency band of the first filtering unit 2101 is higher than the operating frequency band of the second filtering unit 2102. The second filtering unit 2102 is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100.

[0087] It should be noted that by improving the second filtering unit 2102 with a lower working frequency band in the carrier aggregation requirement, the absolute value of the return loss in the high frequency band can be more significantly reduced, so that when the first filtering unit 2101 and the second filtering unit 2102 are used in conjunction, the passband loss generated by the target receiving filter can be more significantly reduced.

[0088] It can be understood that the first filtering unit 2102 can also be configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100 described above. In the embodiment of the present application, the first filtering unit 2101 and the second receiving filtering unit 2102 are both configured as follows Figure 1-2 , Figure 6-13 The filter 100 can more significantly achieve the effect of reducing the passband loss of the RF receiving module 200.

[0089] It should be noted that the first filtering unit 2101 and the second filtering unit 2102 can be specifically understood as filters integrated in the same filter chip and having different operating frequency bands.

[0090] It can be understood that the target receiving filter may be the first receiving filter or the second receiving filter. Preferably, the target receiving filter is the second receiving filter.

[0091] The RF receiving module 200 described in the above embodiment includes a plurality of receiving filters 210, and at least two receiving filters 210 of the plurality of receiving filters 210 are configured to implement carrier aggregation of RF signals of different frequency bands. Among them, at least one of the at least two receiving filters 210 is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100 can reduce the capacitance to ground at the input end of the configured receiving filter 210, thereby reducing the absolute value of the return loss in the high frequency band, so that when used in conjunction with the receiving filter 210 with carrier aggregation requirements, it can reduce the passband loss generated by the RF receiving module 200.

[0092] Please refer to Fig.19 , Fig.19 A schematic diagram of an implementation of a radio frequency front-end module provided in an embodiment of the present application.

[0093] like Fig.19 As shown, the RF front-end module 300 includes a plurality of filters 310, and at least two filters 310 of the plurality of filters 310 are configured to implement carrier aggregation of RF signals of different frequency bands. At least one of the at least two filters 310 is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100.

[0094] It should be noted that carrier aggregation is a key technology for achieving higher performance wireless communications, enabling network operators to use their spectrum resources more flexibly while providing users with faster and more reliable wireless services. At least two filters 310 are configured to achieve carrier aggregation of RF signals in different frequency bands, so that the RF front-end module 300 allows the simultaneous use of multiple carriers on multiple frequency bands to increase data transmission rate and system capacity.

[0095] For example, Fig. 20 As shown, at least two filters 310 include a first filter 311 and a second filter 312. The operating frequency band of the first filter 311 is higher than the operating frequency band of the second filter 312. The second filter 312 is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100, wherein the first filter 311 and the second filter 312 are configured to implement carrier aggregation of radio frequency signals in different frequency bands.

[0096] It should be noted that by improving the second filter 312 with a lower working frequency band in the carrier aggregation requirement, the absolute value of the return loss in the high frequency band of the second filter 312 can be more significantly reduced, so that when the first filter 311 and the second filter 312 are used in conjunction, the passband loss of the RF front-end module 300 can be more significantly reduced.

[0097] It can be understood that the first filter 311 can also be configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100 described above. In the embodiment of the present application, both the first filter 311 and the second filter 312 are configured as follows Figure 1-2 , Figure 6-13 The filter 100 described above can more significantly achieve the effect of reducing the passband loss of the RF front-end module 300.

[0098] In one embodiment, if Fig.21 As shown, at least two filters 310 are both receiving filters 3101. The at least two receiving filters 3101 are configured to implement carrier aggregation of radio frequency signals in different frequency bands.

[0099] In one embodiment, if Fig. 22 As shown, at least one of the at least two filters 310 is a receiving filter 3101, and at least one of the at least two filters 310 is a transmitting filter 3102. The at least one receiving filter 3101 and the at least one transmitting filter 3102 are configured to implement carrier aggregation of radio frequency signals of different frequency bands.

[0100] It is understandable that if Fig.21 and Fig. 22 As shown, other filters 310 in the RF front-end module 300 may be receiving filters 3101 or transmitting filters 3102, and the embodiments of the present application do not specifically limit this.

[0101] In one embodiment, the at least two filters 310 include a target filter. The target filter includes a third filter unit and a fourth filter unit. The third filter unit and the fourth filter unit are configured to implement carrier aggregation of radio frequency signals in different frequency bands. At least one of the third filter unit and the fourth filter unit is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100.

[0102] The target filter and at least one other filter 310 are configured to achieve carrier aggregation of radio frequency signals in different frequency bands. Improving at least one of the third filter unit and the fourth filter unit can reduce the capacitance to ground at the input end of the target filter, thereby reducing the absolute value of the return loss in the high frequency band, so that when used in conjunction with at least one other filter 310, the passband loss generated by the radio frequency front-end module 300 can be reduced.

[0103] In one embodiment, the operating frequency band of the third filter unit is higher than the operating frequency band of the fourth filter unit. The fourth filter unit is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100.

[0104] It should be noted that by improving the fourth filter unit with a lower working frequency band in the carrier aggregation requirement, the absolute value of the return loss in the high frequency band can be more significantly reduced, so that when the third filter unit and the fourth filter unit are used in conjunction, the passband loss generated by the target filter can be more significantly reduced.

[0105] It can be understood that the third filtering unit can also be configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100 described above. In the embodiment of the present application, the third filter unit and the fourth filter unit are configured as follows Figure 1-2 , Figure 6-13 The filter 100 described above can more significantly achieve the effect of reducing the passband loss of the RF front-end module 300.

[0106] The RF front-end module 300 described in the above embodiment includes a plurality of filters 310, and at least two filters 310 of the plurality of filters 310 are configured to implement carrier aggregation of RF signals of different frequency bands. At least one of the at least two filters 310 is configured as in the embodiment of the present application. Figure 1-2 , Figure 6-13 The filter 100 described above can reduce the capacitance to ground at the input end of the configured filter 310, thereby reducing the absolute value of the return loss in the high frequency band, so that when used in conjunction with other filters 310 that have carrier aggregation requirements, it can reduce the passband loss generated by the RF front-end module 300.

[0107] This embodiment provides a radio frequency front-end module, which is a component that integrates two or more discrete devices such as a radio frequency switch, a low noise amplifier, a filter, a duplexer, a power amplifier, and a transformer into an independent module, thereby improving the integration and hardware performance of the radio frequency front-end module and miniaturizing its size. Specifically, the radio frequency front-end module can be applied to 4G and 5G communication devices such as smart phones, tablet computers, and smart watches.

[0108] With the development of information technology, 5G technology and 5G equipment have higher requirements for the performance of RF front-end modules. The technical solution provided in this application can provide a filter and a RF front-end module, which can effectively suppress the nonlinear distortion generated by the filter, so as to better meet the needs of 5G technology, and therefore can be applied to 5G equipment.

[0109] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements.

[0110] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

1. A filter, characterized in that: The filter comprises an input terminal, an output terminal, a series arm resonator group, a parallel arm resonator group and a longitudinally coupled surface acoustic wave resonator, wherein: The longitudinally coupled surface acoustic wave resonator and the series arm resonator group are both connected to a series path between the input terminal and the output terminal; A first end of the parallel arm resonator group is connected between the longitudinally coupled surface acoustic wave resonator and the output terminal, and a second end of the parallel arm resonator group is connected to a ground terminal.

2. The filter according to claim 1, characterized in that The series arm resonator group includes a first series arm resonator group connected to the output end of the longitudinally coupled surface acoustic wave resonator; The parallel arm resonator group includes a first parallel arm resonator group, a first end of the first parallel arm resonator group is connected between the output end of the longitudinally coupled surface acoustic wave resonator and the input end of the first series arm resonator group, and a second end of the first parallel arm resonator group is connected to a ground terminal.

3. The filter according to claim 2, characterized in that The first parallel arm resonator group includes a plurality of first resonators connected in parallel.

4. The filter according to claim 2, characterized in that The parallel arm resonator group also includes at least one second parallel arm resonator group, a first end of the second parallel arm resonator group is connected between the output end of the first series arm resonator group and the output terminal, and a second end of the second parallel arm resonator group is connected to the ground terminal.

5. The filter according to claim 2, characterized in that The series arm resonator group further includes at least one second series arm resonator group, and a path between two adjacent second series arm resonator groups is connected to a first end of at least one second parallel arm resonator group; A path between a second series arm resonator group adjacent to the first series arm resonator group and the first series arm resonator group is connected to a first end of at least one second parallel arm resonator group.

6. The filter according to claim 4, characterized in that At least one of the first series arm resonator group, the second parallel arm resonator group, and the first parallel arm resonator group includes at least one resonator.

7. The filter according to any one of claims 1 to 6, characterized in that: The filter also includes an inductor unit and at least one third series arm resonator group; the first end of the inductor unit is connected to the input terminal, and the second end of the inductor unit is connected to the ground terminal; each third series arm resonator group is connected in series between the input terminal and the input end of the longitudinally coupled surface acoustic wave resonator.

8. The filter according to claim 7, characterized in that The third series-arm resonator group includes a plurality of second resonators connected in cascade.

9. The filter according to any one of claims 1 to 6, characterized in that: The longitudinally coupled surface acoustic wave resonator includes a piezoelectric substrate and at least two interdigital electrodes arranged on the piezoelectric substrate.

10. The filter according to claim 9, characterized in that The longitudinally coupled surface acoustic wave resonator comprises a first longitudinally coupled surface acoustic wave resonator and a second longitudinally coupled surface acoustic wave resonator connected in parallel.

11. The filter according to claim 10, characterized in that The longitudinally coupled surface acoustic wave resonator further comprises a third longitudinally coupled surface acoustic wave resonator and a fourth longitudinally coupled surface acoustic wave resonator; The third longitudinally coupled surface acoustic wave resonator is connected in series with the first longitudinally coupled surface acoustic wave resonator, and the fourth longitudinally coupled surface acoustic wave resonator is connected in series with the second longitudinally coupled surface acoustic wave resonator; The input end of the first longitudinally coupled surface acoustic wave resonator is connected to the input end of the second longitudinally coupled surface acoustic wave resonator, and the output end of the third longitudinally coupled surface acoustic wave resonator is connected to the output end of the fourth longitudinally coupled surface acoustic wave resonator.

12. The filter according to any one of claims 1 to 6, characterized in that: The filter is a receive filter.

13. A radio frequency receiving module, characterized in that: The method comprises a plurality of receiving filters, wherein at least two receiving filters of the plurality of receiving filters are configured to implement carrier aggregation of radio frequency signals of different frequency bands; At least one of the at least two receiving filters is configured as a filter as claimed in any one of claims 1-13.

14. The radio frequency receiving module according to claim 13, characterized in that: It also includes a switch unit, wherein a first port of the switch unit is used to connect to an antenna, and a second port of the switch unit is respectively connected to an input terminal of each of the receiving filters.

15. The radio frequency receiving module according to claim 13, characterized in that: A low noise amplifier is also included, and the low noise amplifier is connected to the output terminal of each of the receiving filters.

16. The radio frequency receiving module according to claim 13, characterized in that: The at least two receiving filters include a first receiving filter and a second receiving filter, the operating frequency band of the first receiving filter is higher than the operating frequency band of the second filter, and the second filter is configured as a filter as described in any one of claims 1-13.

17. The radio frequency receiving module according to claim 13, characterized in that: The at least two receiving filters include a target receiving filter; the target receiving filter includes a first filtering unit and a second filtering unit; The first filtering unit and the second filtering unit are configured to implement carrier aggregation of radio frequency signals in different frequency bands; At least one of the first filtering unit and the second filtering unit is configured as a filter according to any one of claims 1-13.

18. The radio frequency receiving module according to claim 17, characterized in that: The operating frequency band of the first filtering unit is higher than the operating frequency band of the second filtering unit; The second filtering unit is configured as a filter according to any one of claims 1-13.

19. A radio frequency front-end module, characterized in that: The method comprises a plurality of filters, wherein at least two filters of the plurality of filters are configured to implement carrier aggregation of radio frequency signals of different frequency bands; Wherein, at least one of the at least two filters is configured as a filter as claimed in any one of claims 1-13.

20. The radio frequency front-end module according to claim 19, characterized in that: The at least two filters include a first filter and a second filter, the operating frequency band of the first filter is higher than the operating frequency band of the second filter, and the second filter is configured as the filter according to any one of claims 1-13.

21. The radio frequency front-end module according to claim 19, characterized in that: The at least two filters are both receive filters.

22. The radio frequency front-end module according to claim 19, characterized in that: At least one of the at least two filters is a receiving filter, and at least one of the at least two filters is a transmitting filter.

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