CN217037168U - Hierarchical receiving module, radio frequency front end and terminal - Google Patents

Abstract

The utility model belongs to the technical field of filters, and particularly relates to a hierarchical receiving module, a radio frequency front end and a terminal. The grading receiving module comprises an antenna end, at least two single-pole multi-throw switches and a plurality of band-pass filter circuits, wherein the single-pole multi-throw switches are selectively connected with the band-pass filter circuits; the band-pass filter circuit comprises an interface, a filter and a resonator assembly connected between the interface and the filter, wherein the resonator assembly comprises at least two resonators which are connected in cascade, and the single-pole multi-throw switch is selectively connected with the interface. In the utility model, a plurality of resonators are cascaded at the front end of the filter to increase the impedance value of the Smith circle in the CA frequency band, so that the insertion loss of the filter in the CA state can be reduced under the condition of not influencing the transmission characteristic of the filter in the single-open state, and the performance of the filter in the CA state is improved.

Description

Hierarchical receiving module, radio frequency front end and terminal

Technical Field

The utility model belongs to the technical field of filters, and particularly relates to a hierarchical receiving module, a radio frequency front end and a terminal.

Background

In a mobile phone, it is required that one terminal supports a plurality of frequency bands and radio systems. In a radio frequency front end circuit compatible with multi-frequency and multi-mode, even in the case of a Carrier Aggregation (CA) system, it is necessary to perform high-speed processing without deteriorating the quality of a plurality of transmission/reception signals. The dfem (stage receiver module) is a kind of rf module, which encapsulates the rf switch and the filter together for implementing the functions of switching the diversity path and selecting the signal.

Generally, in a hierarchical receiving module, a resonator is arranged in series between a radio frequency switch and a filter, and a grounding inductor is connected in parallel on a circuit between the resonator and the radio frequency switch, the resonator in series and the inductor in parallel are used for changing the imaginary part of the impedance of the filter, so that the impedance circle is rotated to be close to an open circuit point, the absolute value of the impedance is increased, and the insertion loss of a required CA frequency band is correspondingly reduced. But the insertion loss of the required CA frequency band is not greatly improved by adjusting the imaginary part of the impedance to increase the absolute value of the impedance.

SUMMERY OF THE UTILITY MODEL

The utility model provides a hierarchical receiving module, a radio frequency front end and a terminal, aiming at the technical problem that the insertion loss of a CA frequency band is not improved greatly by increasing an impedance imaginary part in the prior art.

In view of the above technical problems, a first embodiment of the present invention provides a hierarchical receiving module, including an antenna end, at least two single-pole multi-throw switches and a plurality of band-pass filter circuits, wherein the single-pole multi-throw switches are selectively connected to the band-pass filter circuits;

the band-pass filter circuit comprises an interface, a filter and a resonator assembly connected between the interface and the filter, wherein the resonator assembly comprises at least two resonators which are connected in cascade, and the single-pole multi-throw switch is selectively connected with the interface.

Optionally, the stepped receiving module further includes an inductor, one end of the inductor is connected to a line between the interface and the resonator assembly, and the other end of the inductor is grounded.

Optionally, each resonator in the resonator assembly comprises two reflectors and an IDT located between the two reflectors, the IDT comprises two comb-shaped electrodes arranged oppositely, and electrode fingers of the two comb-shaped electrodes are arranged in a mutually-crossing manner; the number of electrode fingers of each resonator is positively correlated with the number of cascaded resonators in the resonator assembly.

Optionally, the number of electrode fingers of each resonator in the resonator assembly is the same.

Optionally, the resonant frequency of each resonator in the resonator assembly is the same.

Optionally, the filter is a ladder filter.

Optionally, the filter is a hybrid structure filter.

Optionally, the hybrid structure filter comprises a ladder filter and a DMS filter connected to the ladder filter.

Another embodiment of the present invention further provides a radio frequency front end, including the above hierarchical receiving module.

Another embodiment of the present invention further provides a terminal, which includes the above hierarchical receiving module.

The band-pass filter circuit comprises an interface, a filter and a resonator component connected between the interface and the filter, wherein the resonator component comprises at least two cascaded resonators, and the switch is selectively connected with the interface; a plurality of the resonators are cascaded between the interface and the filter compared to one resonator in series between the interface and the filter. In the utility model, a plurality of resonators are cascaded at the front end of the filter to increase the impedance value of the Smith circle in the CA frequency band, so that the insertion loss of the filter in the CA state can be reduced under the condition of not influencing the transmission characteristic of the filter in the single-open state, and the performance of the filter in the CA state is improved.

Drawings

The utility model is further illustrated by the following examples in conjunction with the drawings.

FIG. 1 is a partial circuit schematic of an RF front end;

fig. 2 is a schematic diagram of a prior art hierarchical receiving module with only one resonator;

fig. 3 is a schematic diagram of a hierarchical receiving module according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating a resonator assembly of a stepped receive module according to an embodiment of the present invention;

FIG. 5 is a graph of the transmission characteristics of the filter in the single ON state;

FIG. 6 is the insertion loss of the filter in the single on state;

FIG. 7 is a Smith chart at a desired CA band;

FIG. 8 is a graph of the absolute value of the impedance of the filter in the desired CA band;

FIG. 9 is a graph of the transmission characteristics of one of the filter passbands in the CA state;

fig. 10 is a schematic diagram of an rf front end according to an embodiment of the present invention.

The reference numerals in the specification are as follows:

10. a grading receiving module; 1. a single-pole, multi-throw switch; 2. a band-pass filter circuit; 21. an interface; 22. a filter; 221. a ladder-structured filter; 222. a hybrid structure filter; 23. a resonator assembly; 231. a resonator; 2311. a reflector; 2312. an IDT; 2313. an electrode finger; 24. an inductance; 3. an antenna end; 4. a signal processing circuit; 5. a received signal amplifying circuit; 20. a radio frequency front end.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

It is to be understood that the terms "upper", "lower", "left", "right", "front", "rear", "middle", and the like, indicate orientations or positional relationships that are based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and thus, are not to be construed as limiting the present invention.

Fig. 1 is a partial circuit diagram of the rf front end 20, where ANT is the antenna terminal 3, and BPF1-8 is the filter 22, which is not limited in number. After receiving signals from the antenna terminal 3, different filters 22 are selectively connected through the two single-pole multi-throw switches 1, so that the signals at the antenna terminal 3 are processed by the filters 22 selectively connected by the single-pole multi-throw switches 1. In fig. 1, there may be 2 single-pole multi-throw switches 1, or there may be 3 or more single-pole multi-throw switches 1, and the number thereof is not limited.

Fig. 2 is a schematic diagram of a stepped receiving module 30 provided in the prior art, which includes two band-pass filter circuits 6, in each of the band-pass filter circuits 6, an interface 21, a resonator 61 and a filter 22 connected in series in sequence, and a grounding inductor 24 connected in parallel in the circuit between the interface 21 and the resonator 61; of the two band pass filter circuits 6, one filter 22 is a two-ladder filter (not limited to the two-ladder filter in fig. 2), and the other filter 22 is a hybrid-type structure filter 222 (not limited to the hybrid-type structure filter 222 in section 2) in which a ladder filter is combined with a DMS filter. Illustratively, the inductor 24 and the resonator 61 form a phase shifting network LC, which changes the imaginary part of the impedance to rotate the impedance circle close to the open point, so that the absolute value of the impedance is increased and the insertion loss of the required CA band is correspondingly reduced.

Fig. 3 is a schematic diagram of an antenna end 3 and a stepped receiving module 10 according to an embodiment of the present invention, which includes two bandpass filter circuits 2, where the bandpass filter circuit 2 includes an interface 21, a resonator assembly 23, and a filter 22, which are connected in series in sequence, and the resonator assembly 23 includes a plurality of resonators 231 connected in cascade; the filter 22 in one of the band-pass filter circuits 2 is a two-ladder filter (not limited to the two-ladder filter form of figure 3); the filter 22 in the other bandpass filter 22 circuit is a hybrid structured filter 222 (not limited to the form of hybrid structured filter 222 in section 3) that is a combination of a ladder filter and a DMS filter; the type and arrangement of the filter 22 are not limited in this embodiment.

It should be noted that the resonator 231 in the present invention has different structural parameters from the resonator 61 in the prior art, and for the sake of identification, two different reference numerals are used; the bandpass filter circuit 2 of the present invention has different structural parameters from the conventional bandpass filter circuit 6, and therefore, two different reference numerals are used.

As shown in fig. 3, a hierarchical receiving module 10 according to a first embodiment of the present invention includes an antenna terminal 3, at least two single-pole-multiple-throw switches 1 and a plurality of band-pass filter circuits 2, where the single-pole-multiple-throw switches 1 are selectively connected to the band-pass filter circuits 2; it can be understood that the number of the band-pass filter circuits 2 may be set according to actual requirements, for example, the number of the band-pass filter circuits 2 is set to be 8, 10, etc., and a plurality of the band-pass filter circuits 2 are in a parallel state; one end of each of the single-pole multi-throw switches 1 is connected to the antenna terminal 3, and the other end of each of the single-pole multi-throw switches 1 is selectively connected to different bandpass filter circuits 2. Further, the single-pole multi-throw switch 1 switches and connects different band-pass filter circuits 2 by a Carrier Aggregation (CA) method and a non-CA method.

The band-pass filter circuit 2 comprises an interface 21, a filter 22 and a resonator assembly 23 connected between the interface 21 and the filter 22, wherein the resonator assembly 23 comprises at least two resonators 231 connected in cascade, and the single-pole multi-throw switch 1 is selectively connected with the interface 21. It can be understood that the number of the resonators 231 in the resonator assembly 23 may be set according to actual requirements, for example, 2, 3, 4, etc. of the resonators 231 are arranged in the resonator assembly 23; the antenna end 3 is connected with different interfaces 21 through the single-pole multi-throw switch 1, that is, the antenna end 3 is selectively connected with different band-pass filter circuits 2 through the single-pole multi-throw switch 1.

In the utility model, the band-pass filter circuit 2 comprises an interface 21, a filter 22 and a resonator assembly 23 connected between the interface 21 and the filter 22, the resonator assembly 23 comprises at least two cascaded resonators 231, and the single-pole multi-throw switch 1 is selectively connected with the interface 21; compared with the case where one resonator 61 is connected in series between the interface 21 and the filter 22, the present invention can reduce the insertion loss of the filter 22 in the CA state without affecting the transmission characteristics of the filter 22 in the single-open state by connecting the plurality of resonators 231 in series at the front end of the filter 22 to increase the impedance value of the smith circle in the CA band, thereby improving the performance of the filter 22 in the CA state.

In the present invention, as shown in fig. 3, the stepped receiving module 10 further includes an inductor 24, one end of the inductor 24 is connected to the line between the interface 21 and the resonator assembly 23, and the other end of the inductor 24 is grounded. It is understood that the inductor 24 and the resonator assembly 23 form an LC phase shift network, the inductor 24 can change the imaginary part of the impedance, and the plurality of resonators 231 can change the real part of the impedance, so that the impedance circle is rotated to be close to the open point, thereby increasing the absolute value of the impedance and further reducing the insertion loss of the required CA band. In the process of packaging the hierarchical receiving module 10, the resonators 231 and the filter 22 are packaged as one component, and the inductor 24 is packaged as another component.

In one embodiment, as shown in fig. 4, each resonator 231 in the resonator assembly 23 includes two reflectors 2311 and an IDT2312 located between the two reflectors 2311, the IDT2312 includes two comb-shaped electrodes disposed oppositely, and electrode fingers 2313 of the two comb-shaped electrodes are arranged to be crossed with each other; the number of the electrode fingers 2313 of each of the resonators 231 is positively correlated with the number of the resonators 231 cascaded in the resonator assembly 23. It can be understood that, a plurality of resonators 231 are cascaded between the interface 21 and the filter 22 (and the structural parameters of each resonator 231 are the same), compared with the case that one resonator 61 is connected in series between the interface 21 and the filter 22, the aperture of the resonators before and after the cascade connection is not changed, and the resistance can be ensured to be increased under the condition that the capacitance value of the filter 22 is not changed by cascading a plurality of identical resonators 231 and correspondingly changing the electrode fingers 2313, so that the impedance value of the smith circle to the CA band is larger.

Specifically, the number N' of each resonator 231 after cascading is related to the number N of series stages: n ═ N × N. N is the number of electrode fingers in a resonator 61 when one resonator 61 is connected in series between the interface 21 and the filter 22. When N is 2 (that is, the resonator assembly 23 includes 2 resonators 231 cascaded), in order to ensure that the resistance R of the filter 22 is consistent with the capacitance C, 1/C 'is 1/C +1/C, that is, C' is C/2, R 'is 2R (C' is a capacitance value after the resonators 231 are cascaded, R 'is a resistance value after the resonators 231 are cascaded, C is a capacitance value after the resonator 61 is connected in series, and R' is a resistance value after the resonator 61 is connected in series), so that the capacitances before and after the cascade are consistent only by connecting N × 2 the resonators 231 after the resonators 231 are cascaded. It should be noted that theoretically, after an infinite number of resonators 231 are cascaded, the impedance circle can be close to the outermost circle, but in practice, the number of series connections needs to be determined according to the chip area, and the larger the number of cascade connections, the larger the chip area, and the situation that the chip area is not suitable for practical application is.

Fig. 5 shows the transmission characteristic of the filter 22 in the single-open state, with the frequency (in freq, GHz) on the abscissa and the transmission characteristic dB on the ordinate, and fig. 6 shows the insertion loss of the filter 22 in the single-open state, with the frequency (in freq, GHz) on the abscissa and the insertion loss dB on the ordinate. In fig. 5 and 6, the long dashed line is the performance of the prior art single-open filter 22 (i.e. one resonator 61 in series between the interface 21 and the filter 22); the short-dashed line shows the performance of the single-open filter 22 when the 2 resonators 231 (i.e., n ═ 2) are cascaded in the present invention; the solid line shows the performance of the single-open filter 22 when 3 resonators 231 (i.e., n-3) are cascaded in the present invention. As can be seen from fig. 5 and 6, when the plurality of resonators 231 are cascaded, the transmission characteristic of the filter 22 in the single-on state is hardly affected, and the insertion loss is less affected. In general, two or three filters 22 are simultaneously switched into the operating state of the staged receiving module through the single-pole multi-throw switch 1, and in the CA state, the plurality of filters 22 are simultaneously in the operating state, and the filters 22 in the band-pass filter circuit 2 are not interfered with each other, so that the insertion loss of the filters 22 is reduced.

Fig. 7 is a smith chart of the desired CA band with the long dashed line indicating the position of the prior art (i.e. a resonator 61 in series between the interface 21 and the filter 22) on the smith chart; the short dashed line is the position of the smith chart when the present invention cascades 2 resonators 231 (i.e., n-2); the solid line is the position of the smith chart when 3 resonators 231 (i.e., n-3) are cascaded in accordance with the present invention. From fig. 7, it can be derived that the absolute value of the impedance increases closer to the right side when the 3 resonators 231 are cascaded, the closer to the right side the smith chart is located, where the left side is in the short circuit state and the right side is in the open circuit state.

Fig. 8 shows the absolute value of the impedance of the filter 22 in the desired CA band, the long dashed line representing the prior art solution (i.e. one resonator 61 in series between the interface 21 and the filter 22); the short dashed line represents the inventive scheme of cascading 2 resonators 231 (i.e., n-2); the solid line represents the scheme of the present invention to cascade 3 resonators 231 (i.e., n-3). It can be derived from fig. 7 that the larger the absolute value of the impedance obtained by cascading 3 resonators 231.

Fig. 9 shows the passband transmission characteristics of one of the filters 22 in the CA state, with the abscissa representing frequency (in freq, GHz), the ordinate representing insertion loss (in dB), and the long dashed line representing the insertion loss of the prior art (i.e. one resonator 61 in series between the interface 21 and the filter 22) in the desired CA band; the short dashed line represents the insertion loss of the cascaded 2 resonators 231 (i.e., n-2) in the required CA band; the long dashed line is the insertion loss of the inventive cascade of 3 resonators 231 (i.e., n-3) in the desired CA band. As can be derived from fig. 9, the more resonators 231 are cascaded, the smaller the insertion loss is theoretically.

The following table shows the insertion loss of the filter 22 in each case when m1, m2, and m3 are 2.496GHz, 2.593GHz, and 2.690GHz, respectively, in fig. 9.

In one embodiment, the structural parameters of each resonator 231 in the resonator assembly 23 are the same. As can be understood, in the cascaded plurality of resonators 231, the structural parameters of each resonator 231 are the same; the structural parameters include the number of electrode fingers 2313, the IDT aperture and the distance between the centerlines of two adjacent electrode fingers 2313; that is, the number of electrode fingers 2313 of each of the resonators 231, the IDT aperture, and the center lines of the adjacent two electrode fingers 2313 are the same; here, the IDT2312 aperture is the length of the overlapping portion of the adjacent two electrode fingers 2313.

In one embodiment, the resonant frequency of each resonator 231 in the resonator assembly 23 is the same. It is understood that, in the plurality of resonators 231 cascaded in series, the resonant frequency of each resonator 231 is the same.

In one embodiment, as shown in FIG. 3, the filter 22 is a ladder filter 221. It is to be understood that, in the present invention, the filter 22 is not limited to the ladder filter 221, and may be a two-stage ladder filter, a 3-stage ladder filter, or the like; furthermore, the method is simple. The filter 22 may also be a ladder filter.

In one embodiment, as shown in FIG. 3, the filter 22 is a hybrid structure filter 222. Preferably, the hybrid structure filter 222 includes a ladder filter and a DMS filter connected between the resonator assembly 23 and the ladder filter. It is understood that, in the hierarchical receiving module 10, one of the cases is: the ladder filter is connected between the DMS filter and the resonator assembly 23; the other situation is as follows: the DMS filter is connected between the ladder filter and the resonator assembly 23. In the present invention, the filters 22 having the same configuration may be applied to different bandpass filter circuits 2, or the filters 22 having different configurations may be applied to different bandpass filter circuits 2, that is, the filters 22 are not limited to the hybrid-type configuration filter 222.

As shown in fig. 10, another embodiment of the present invention further provides an rf front end 20, which includes the above-mentioned hierarchical receiving module 10. In a specific embodiment, the rf front end 20 further includes a signal processing Circuit 4 (RFIC: Radio Frequency Integrated Circuit), and the band pass filter Circuit 2 further includes a received signal amplifying Circuit 5; the antenna end 3 is selectively connected with the band-pass filter circuit 2 through the single-pole multi-throw switch 1; in each of the band-pass filter circuits 2, the interface 21, the resonator assembly 23, the filter 22, and the reception signal amplification circuit 5 are connected in series in this order, and all the reception signal amplification circuits 5 are connected to the signal processing circuit 4.

The present invention further provides a terminal, including the above hierarchical receiving module 10.

The above description is only an example of the hierarchical receiving module 10 and the rf front end 20, and should not be construed as limiting the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A grading receiving module is characterized by comprising an antenna end, at least two single-pole multi-throw switches and a plurality of band-pass filter circuits, wherein the single-pole multi-throw switches are selectively connected with the band-pass filter circuits;

the band-pass filter circuit comprises an interface, a filter and a resonator assembly connected between the interface and the filter, wherein the resonator assembly comprises at least two resonators which are connected in cascade, and the single-pole multi-throw switch is selectively connected with the interface.

2. The stepped receive module of claim 1, further comprising an inductor, one end of the inductor being coupled to the line between the interface and the resonator assembly, the other end of the inductor being coupled to ground.

3. The stepped receive module of claim 1, wherein each of the resonators of the resonator assembly comprises two reflectors and an IDT between the two reflectors, the IDT comprising two oppositely disposed comb electrodes, the electrode fingers of the two comb electrodes being arranged to be interdigitated with each other; the number of electrode fingers of each resonator is positively correlated to the number of cascaded resonators in the resonator assembly.

4. The stepped receiving module of claim 3, wherein the structural parameters of each resonator of the resonator assembly are the same.

5. The stepped receive module of claim 1, wherein the resonant frequency of each resonator of the resonator assembly is the same.

6. The hierarchical receive module of claim 1, wherein the filter is a ladder filter.

7. The hierarchical receive module of claim 1, wherein the filter is a hybrid architecture filter.

8. The hierarchical receive module of claim 7, wherein the hybrid structure filter comprises a ladder filter and a DMS filter coupled to the ladder filter.

9. A radio frequency front end comprising the hierarchical receive module of any one of claims 1 to 8.

10. A terminal comprising the hierarchical receiving module of any of claims 1 to 8.

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