CN115567031A - Filter circuit comprising matching structure - Google Patents
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
- H03H9/56—Monolithic crystal filters
- H03H9/566—Electric coupling means therefor
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
- H03H9/58—Multiple crystal filters
- H03H9/60—Electric coupling means therefor
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
- H03H9/6423—Means for obtaining a particular transfer characteristic
- H03H9/6433—Coupled resonator filters
- H03H9/644—Coupled resonator filters having two acoustic tracks
- H03H9/6456—Coupled resonator filters having two acoustic tracks being electrically coupled
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Abstract
In an embodiment of the present disclosure, a filter circuit comprising a matching structure is provided, the filter circuit comprising a resonator network and the filter circuit comprising a specific matching structure at least one signal terminal, the specific matching structure comprising an inductive device and a capacitive device. With the processing scheme of the present disclosure, out-of-band rejection at high frequencies may be improved.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a filter circuit including a matching structure, and more particularly, to an acoustic wave filter, a duplexer, and a multiplexer including a matching structure.
Background
Among the indexes of the filter, especially, the acoustic wave filter, the return loss is one of the most important indexes for measuring the matching, and the quality of the return loss directly determines the comprehensive performance of the acoustic wave filter. In addition, since the acoustic wave filter is a nonlinear device, when a signal of a certain power is applied, a nonlinear signal component is generated, and the generated nonlinear signal component causes serious interference to signals of other frequency bands, thereby deteriorating signal transmission quality, it is necessary to improve the nonlinear performance of the filter to improve the performance of the communication system.
In the prior art, on one hand, the nonlinear performance of the filter is improved by arranging two or more resonators and realizing the elimination of nonlinear signals through the overturning of electrodes, but the method is related to specific physical arrangement, the change of the surrounding arrangement environment has a large influence on the improvement of the nonlinearity, and the improvement effect cannot be ensured; on the other hand, the nonlinearity is improved by improving the rejection of a specific frequency through the combination of inductance and capacitance, but the method cannot ensure that the index of return loss is not influenced, and the nonlinear improvement is also realized by adding the inductance-capacitance combination at different positions. That is, the matching structure in the prior art cannot guarantee that the return loss is not affected while improving the suppression, and therefore, a matching structure capable of improving the suppression and guaranteeing the return loss is needed.
Disclosure of Invention
Accordingly, embodiments of the present disclosure provide a filter circuit including a matching structure, which at least partially solves the problems of the prior art.
According to an aspect of the embodiments of the present disclosure, there is provided a filter circuit comprising a resonator network and comprising a specific matching structure at least one signal terminal, the specific matching structure comprising an inductive device and a capacitive device.
According to a specific implementation manner of the embodiment of the present disclosure, the specific matching structures are an inductive device connected in series and a capacitive device connected in parallel.
According to a specific implementation of the embodiments of the present disclosure, the series inductive devices and the parallel capacitive devices are connected in a specific order, and the inductive devices are closer to the resonator network than the capacitive devices.
According to a specific implementation of the embodiment of the present disclosure, the filter circuit further includes a first matching structure and a second matching structure located at two ends of the resonator network, and one of the first matching structure and the second matching structure is the specific matching structure.
According to a particular implementation of the disclosed embodiments, the filter circuit comprises at least one transmit filter circuit and at least one receive filter circuit, the at least one transmit filter circuit and the at least one receive filter circuit comprising the resonator network;
the transmission filter circuit and the reception filter circuit are connected via a common terminal; and is
The signal output of the transmit filter circuit includes the particular matching structure.
According to a specific implementation manner of the embodiment of the present disclosure, the filter circuit further includes a third matching structure, the transmit filter circuit and the receive filter circuit are connected to the third matching structure via a common terminal, and the third matching structure is the specific matching structure.
According to a specific implementation of the embodiment of the present disclosure, the transmission filter circuit further includes a first matching structure and a second matching structure located at two ends of the resonator network, and one of the first matching structure and the second matching structure near the common end is the specific matching structure.
According to a specific implementation of the disclosed embodiment, the specific matching structure is located at a side of the common terminal close to the transmit filter circuit, or,
the specific matching structure is located on a side of the common terminal away from the transmit filter circuit.
According to a specific implementation of the embodiment of the present disclosure, one of the series inductive device and the parallel capacitive device of the specific matching structure is located at a side of the common terminal close to the transmission filter circuit, and the other is located at a side of the common terminal far from the transmission filter circuit.
According to a specific implementation of the embodiments of the present disclosure, the resonator networks include an inductance to ground, and the inductive device of the specific matching structure is coupled to the inductance to ground of at least one of the resonator networks.
According to a specific implementation manner of the embodiment of the present disclosure, the inductance value L of the series-connected inductive device and the capacitance value C of the parallel-connected capacitive device of the specific matching structure satisfy the following condition:
L*C*f＝c’，
wherein c' ranges from 0.01 to 0.05; or c' ranges from 0.02 to 0.04; or c' =0.03; and is
Wherein the inductance value L is given in units of H, the capacitance value C is given in units of F, F is the center frequency of the filter, and is given in units of Hz, which represents the multiplication.
According to a specific implementation manner of the embodiment of the present disclosure, the filter circuit is a duplexer or a multiplexer, and the inductive device of the specific matching structure is an inductor and/or the capacitive device is a capacitor.
In a second aspect, an embodiment of the present disclosure provides a filter including the filter circuit according to the first aspect of the present disclosure or any implementation manner thereof.
In a third aspect, an embodiment of the present disclosure provides an electronic device including the filter circuit according to the first aspect of the present disclosure or any implementation manner thereof, or including the filter according to the second aspect of the present disclosure.
In an embodiment of the disclosure, a filter circuit comprising a matching structure is provided, the filter circuit comprising a resonator network and the filter circuit comprising a specific matching structure at least one signal terminal, the specific matching structure being an inductive device in series and a capacitive device in parallel. With the processing scheme of the present disclosure, out-of-band rejection at high frequencies may be improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings needed to be used in the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present disclosure, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1a is a topological structure of a filter provided by an embodiment of the present disclosure;
fig. 1b is a topology of a duplexer and a multiplexer according to an embodiment of the present disclosure;
FIG. 2 is a diagram of a matching structure provided by an embodiment of the present disclosure;
fig. 3a is a topology of a filter provided by an embodiment of the present disclosure;
fig. 3b is a schematic diagram of a duplexer and a multiplexer according to an embodiment of the present disclosure;
fig. 3c is a schematic diagram of a duplexer and a multiplexer according to an embodiment of the present disclosure;
fig. 3d shows a topology of a duplexer and a multiplexer according to an embodiment of the present disclosure;
fig. 3e is a topology of a duplexer and a multiplexer according to an embodiment of the present disclosure;
FIG. 4a is a diagram illustrating a filter matching structure and coupling to ground inductance provided by an embodiment of the present disclosure;
FIG. 4b illustrates the coupling of the diplexer and multiplexer matching structure and ground inductance provided in an embodiment of the present disclosure;
FIG. 5 is a graph of the improvement in out-of-band rejection provided by certain matching structures of embodiments of the present disclosure;
fig. 6 is an illustration of the effect of different values of the specific matching structure c on return loss according to an embodiment of the present disclosure; and is provided with
Fig. 7 is an improvement in out-of-band rejection for a coupling structure provided by an embodiment of the present disclosure.
Detailed Description
The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.
The embodiments of the present disclosure are described below with specific examples, and other advantages and effects of the present disclosure will be readily apparent to those skilled in the art from the disclosure of the present disclosure. It is to be understood that the described embodiments are merely illustrative of some, and not restrictive, of the embodiments of the disclosure. The disclosure may be embodied or carried out in various other specific embodiments, and various modifications and changes may be made in the details within the description without departing from the spirit of the disclosure. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.
It is noted that various aspects of the embodiments are described below within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the disclosure, one skilled in the art should appreciate that one aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to or other than one or more of the aspects set forth herein.
It should be further noted that the drawings provided in the following embodiments are only schematic illustrations of the basic concepts of the present disclosure, and the drawings only show the components related to the present disclosure rather than the numbers, shapes and dimensions of the components in actual implementation, and the types, the numbers and the proportions of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complicated.
In addition, in the following description, specific details are provided to provide a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects may be practiced without these specific details.
The disclosed embodiments disclose a filter including a specific matching structure, which may be an acoustic wave filter, a duplexer and a multiplexer, or other filter forms or structures. In the following description, the acoustic wave filter, the duplexer, and the multiplexer are taken as examples, and by including a matching structure of a specific inductance and capacitance in the acoustic wave filter, the duplexer, and the multiplexer, out-of-band rejection at a high frequency can be improved.
Furthermore, devices such as acoustic wave filters generate nonlinear power at a certain frequency, generally speaking, nonlinear power includes quadratic nonlinear power, cubic nonlinear power, etc., which occurs near twice the fundamental frequency for quadratic nonlinear power, that is, if the device operates at 1.8GHz, the frequency doubling is 3.6GHz, the quadratic nonlinear power is generated near 3.6 GHz.
The disclosed embodiment generates certain suppression near the double frequency of the fundamental frequency through a matching structure, and the term "suppression" means that a signal can be reflected at the position and is not transmitted along a signal transmission path, so that nonlinear power can be eliminated at the output end, and the nonlinear performance is improved.
That is, in the embodiment of the present disclosure, the target frequency position (for example, at the frequency doubling time) is set as the frequency position where the nonlinear power is generated, and the specific position is set as the position where the suppression is improved, so that the suppression improvement at the target frequency can effectively improve the nonlinear performance.
In the disclosed embodiments, the term "target frequency" refers to the frequency location of interest, and if the second-order nonlinear power is of interest, the target frequency is the second-order frequency, if the third-order nonlinear power is of interest, the target frequency is the third-order frequency, and so on.
In addition, in the implementation of the present disclosure, the inductance capacitance value of the matching structure is constrained to a certain extent, so that the matching characteristic and the return loss can be effectively improved. In addition, by coupling the inductance in the specific matching structure and the ground-to-ground inductance in the filter, the rejection at the target frequency can be improved.
Specifically, in the embodiment of the disclosure, by adding a matching structure, a series inductor and a parallel capacitor device are introduced into a filter, where the series inductor has a certain suppression effect on a high-frequency signal, and the parallel capacitor has a suppression effect on the high-frequency signal, and the superposition of the two devices can improve the high-frequency suppression.
In addition, the introduction of the matching structure can bring obvious influence on return loss, and in the embodiment of the disclosure, through the constraint on the values of the components in the matching structure, the influence of the matching structure on the return loss can be reduced, which is beneficial to improving the index.
In addition, the position of the out-of-band transmission zero can be moved by the coupling action, the transmission zero is moved to the target frequency, and the suppression of the target frequency is improved. The position of the target frequency for generating the nonlinear power is set, and the structure for improving the suppression is positioned at a specific position, so the suppression at the target frequency can be improved, and the nonlinear performance can be effectively improved.
Next, with reference to the drawings, embodiments of the present disclosure are specifically described.
First, referring to fig. 1a, a filter circuit proposed by an embodiment of the present disclosure is described, where an input terminal IN (left side of the view) and an output terminal OUT (right side of the view) are included, and MN1 and MN2 are matching structures, IN the embodiment of the present disclosure, an inductor and/or a capacitor are included IN the matching structure MN1 and the matching structure MN2 on both sides, and the inductor and the capacitor included IN the matching structure may be IN a series form, a parallel form, and the like, and values of devices IN the matching structures may be completely the same, may also be completely different, or may be partially different. In addition, the inductance and capacitance may be other devices having inductance and/or capacitance at the target frequency.
In the disclosed embodiment, the matching structure MN is used to achieve matching and filtering nonlinear power, and the term "matching" refers to performing impedance matching. That is, in the embodiment of the present disclosure, the matching structure MN can achieve both matching and the effect of suppressing nonlinearity.
In addition, the filter also comprises a Resonator network Res (Resonator), wherein the Resonator network Res is built by combining a plurality of resonators in series and parallel and adding a plurality of passive devices to the ground. In the disclosed embodiment, the resonator network Res includes at least one series resonator and one shunt resonator, and at least one ground-to-ground inductor is connected to the shunt resonator. In the disclosed embodiment, the end point of the matching structure MN close to the resonator network Res is end point 1, and the end point far from the resonator network Res is end point 2.
IN the working process of the filter shown IN fig. 1a, a signal enters from an input terminal IN, is impedance-matched and filters a part of nonlinear power through a matching structure MN1, and then passes through a resonator network Res, because the resonator network Res is a nonlinear device, the signal generates additional nonlinear power through the resonator network Res, and then passes through a matching structure MN2, so that on one hand, impedance matching is performed, and on the other hand, the matching structure MN2 filters the nonlinear power generated by the resonator network Res and the nonlinear power entering the input terminal, and then outputs the signal from an output terminal OUT.
In fig. 1a, the matching structure MN2 plays a more critical role in suppressing the nonlinear power generated by the resonator network Res.
Referring next to fig. 1b, it shows the filter of fig. 1a in a duplexer and a multiplexer, wherein the definitions of the resonator networks Res1 and Res2, the matching structures MN1 to MN5, and the endpoints 1 and 2 are the same as those in fig. 1 a.
In fig. 1b, a TX terminal is an input terminal for a transmission signal, an RX terminal is an output terminal for a reception signal, and an ANT terminal is an output terminal for the transmission signal and an input terminal for the reception signal. For a duplexer, a transmitting filter and a receiving filter are included; for the multiplexer, there are additional more transmit filters and more receive filters (i.e. TXn and RXn, for the multiplexer, n is greater than or equal to 2, and the specific structure of the transmit filters and the receive filters of the other paths is temporarily not shown in fig. 1 b), and these transmit filters and the receive filters of the other paths are both connected to Common terminal Common.
Next, the structure of the matching structure proposed by the embodiment of the present disclosure is described with reference to fig. 2, where the structure of this specific matching structure includes an inductor connected in series and a capacitor connected in parallel, where a terminal 2 is one terminal of the connection between the inductor connected in series and the capacitor connected in parallel, and a terminal 1 is the other terminal of the inductor. In other words, after the matching structure of the embodiment of the disclosure is connected into a circuit, the inductors are connected in series and the capacitors are connected in parallel. It should be noted that although an inductance and a capacitance are shown in fig. 2, the inductance may also be an inductive device and the capacitance a capacitive device.
Next, with reference to fig. 3a, a topology of a filter including the specific matching structure in fig. 2 is described, wherein the matching structure MN2 shown by a solid line box is the matching structure in fig. 2, and the corresponding connection modes of the endpoint 1 and the endpoint 2 are as shown in fig. 3 a. That is, in the case of the matching structure in fig. 2 accessing the network, the inductance and capacitance are connected in a particular order, with the inductance closer to the resonator network and the capacitance further from the resonator network. IN fig. 3a, a specific matching structure shown IN fig. 2 is connected to the output OUT of the filter, the input IN of the filter includes a matching structure MN1 indicated by a dashed box, the matching structure MN1 includes an inductor and/or a capacitor, and the connection structure of the inductor and the capacitor and the values of specific devices are not limited. It should be noted that IN the embodiments of the present disclosure, a particular matching structure may also be connected at the input IN of the filter, where similarly the inductance of the particular matching structure is closer to the resonator network and the capacitance is further away from the resonator network.
That is, IN the disclosed embodiment, the filter circuit includes a resonator network Res, and the filter circuit includes a specific matching structure at least one signal terminal (input terminal IN and/or output terminal OUT), and the specific matching structure is an inductive device and a capacitive device connected IN parallel IN series as shown IN fig. 2, and the inductance of the specific matching structure is closer to the resonator network, and the capacitance is further from the resonator network. By this matching structure, out-of-band rejection at high frequencies can be improved.
In a particular embodiment, the resonator network Res contains a matching structure MN1 as an example of a first matching structure and a matching structure MN2 as an example of a second matching structure across it, in which case one of the first and second matching structures may be a specific matching structure.
Next, referring to fig. 3b, the connection of the specific matching structure in fig. 2 in the duplexer or multiplexer is described, wherein the matching structure MN5 shown by a solid line box adopts the matching structure in fig. 2, and the corresponding terminals 1 and 2 are connected as shown in fig. 3b, that is, the inductance of the specific matching structure is closer to the resonator network and the capacitance is further from the resonator network. In fig. 3b, a specific matching structure is connected to the output of the transmit filter of the duplexer and multiplexer, which in this embodiment is connected to the ANT terminal. The input ends of the duplexer and the multiplexer comprise matching structures MN 1-MN 4 represented by dashed boxes, the matching structures comprise inductors and/or capacitors, and the connection structures of the inductors and the capacitors and the values of specific devices are not limited. It should be noted that in the embodiments of the present disclosure, a specific matching structure may also be connected at the transmitting terminal TXn and/or the receiving terminal RXn of the duplexer or multiplexer, where n =1,2,3.
Next, with reference to fig. 3c, a topology of a duplexer and a multiplexer proposed by another embodiment of the present disclosure is described, wherein fig. 3c is similar to fig. 3b, except that a specific matching structure shown in fig. 2 is moved from the position of the matching structure MN5 to the position of the matching structure MN2, and the rest is unchanged.
Next, referring to fig. 3d, a topology of a duplexer and a multiplexer according to another embodiment of the present disclosure is described, where fig. 3d is similar to fig. 3b, except that a specific matching structure is split, an inductor is connected to the Common terminal Common at one end, the other end is connected to the matching structure MN5, and a capacitor is connected to the Common terminal Common, and the others are unchanged.
Next, referring to fig. 3e, a topology of a duplexer and a multiplexer according to another embodiment of the present disclosure is described, where fig. 3e is similar to fig. 3b, except that a specific matching structure is split, one end of an inductor is connected to Common terminal Common, the other end of the inductor is connected to matching structure MN2, and a capacitor is connected to a Common terminal, and the rest is unchanged.
That is, in the disclosed embodiments, the filter circuit includes at least one transmit filter circuit and at least one receive filter circuit, and the at least one transmit filter circuit and the at least one receive filter circuit include a resonator network; the transmit filter circuit and the receive filter circuit are connected via a common terminal and may comprise a specific matching structure at the signal output terminal of the transmit filter circuit (as in fig. 3 b-3 e).
In a specific embodiment, the transmit filter circuit and the receive filter circuit of the filter circuit are connected via a common terminal to a matching structure MN5 as an example of a third matching structure, which is now a specific matching structure (see fig. 3 b).
In another specific embodiment, the transmit filter circuit of the filter circuit comprises a first matching structure (e.g., MN 1) and a second matching structure (e.g., MN 2) located at both ends of the resonator network, and one of the first and second matching structures near the common end is a particular matching structure (e.g., fig. 3 c).
In another embodiment, the specific matching structure is located on the side of the common terminal close to the transmit filter circuit, or,
the specific matching structure is located on a side of the common terminal away from the transmit filter circuit.
In another embodiment one of the series inductive device and the parallel capacitive device of a particular matching structure is located at a side of the common terminal close to the transmit filter circuit and the other is located at a side of the common terminal remote from said transmit filter circuit (see fig. 3d and 3 e).
The filter, the duplexer and the multiplexer in fig. 3a to 3e above introduce the series inductance and the parallel capacitance devices, since the series inductance has a certain suppression effect on the high frequency signal and the parallel capacitance has a same suppression effect on the high frequency signal, the superposition of the two devices can improve the high frequency suppression.
That is, in the embodiments of the present disclosure, a specific matching structure may be included at least one of the signal terminals (the transmitting terminal and/or the receiving terminal) of the filter, the duplexer, and the multiplexer, and the specific matching structure is a combination of an inductor and a capacitor, and this arrangement may improve out-of-band rejection at high frequencies.
In one embodiment, the specific matching structure included in at least one of the signal terminals of the filter, duplexer, and multiplexer is first a series inductor and then a capacitor connected in parallel to ground (as shown in fig. 2), which improves out-of-band rejection at high frequencies.
In another embodiment, the filter may include a specific matching structure only at the signal output, and the duplexer and multiplexer may include a specific matching structure only at the signal output of the transmit filter, which may improve out-of-band rejection at high frequencies.
In another embodiment, the signal output of the transmit filter in the duplexer and multiplexer may be referred to as either in-common or out-of-common, and may also include the case where the inductor and capacitor are one in-common and one out-of-common (as shown in fig. 3 b-3 e).
Next, referring to fig. 4a, the specific matching structure of the filter and the coupling of the resonator network Res to ground inductance are illustrated by taking the structure of fig. 3a as an example.
It should be understood that although fig. 4a is the example of fig. 3a, such coupling is not limited to the above structure, in fig. 4a, the output terminal OUT includes a specific matching structure (series inductance, parallel capacitance), LG1 is the ground-to-ground inductance in the resonator network Res, and in the disclosed embodiment, the ground-to-ground inductance LG1 is embodied in the figure for the purpose of explaining the coupling.
In order to suppress the target frequency, in the embodiment of the present disclosure, the inductance L1 of the specific matching structure and the ground inductance LG1 in the resonator network Res are coupled, the coupling inductance is M, and the generated coupling inductance M can adjust the out-of-band transmission zero, so that the suppression of the target frequency can be improved. In the embodiment of the present disclosure, the reason why the out-of-band transmission zero point is adjusted by the generated coupling inductance is that the position of the transmission zero point is moved by changing the equivalent inductance on the signal transmission path through the formed signal path and moving the position of the inductance-capacitance resonance point (the resonator is a capacitance device).
In the embodiments of the present disclosure, the term "couple" means that there is mutual inductance between two devices or circuits through electromagnetic coupling, and a signal of one path affects a signal of the other path, in other words, a signal path can be formed between the two devices through electromagnetic mutual inductance. The coupling inductance M, i.e. mutual inductance
Where k is the coupling coefficient and L1 and L2 are the inductances of the two devices, respectively, in particular in the case shown in FIG. 4a
Referring to fig. 4b, the specific matching structure of the duplexer and multiplexer and the coupling of the resonator network Res to ground inductance are illustrated by way of example in the structure of fig. 3 b.
It should be understood that although fig. 4b is exemplified by fig. 3b and is not limited to the above-described structure, in fig. 4b, the output terminal of the transmitting filter, i.e. ANT terminal, contains a specific matching structure (series inductance, shunt capacitance), where LGt1 and LGr1 are ground inductances in the resonator network Res1 and the resonator network Res2, and are embodied in this figure for the purpose of illustrating the coupling situation. The L1 and the LGt1 and/or the L1 and the LGr1 generate coupling, coupling inductance is Mt and Mr, and the generated coupling inductance can adjust out-of-band transmission zero points and can improve the suppression of target frequency. In particular, a coupled inductor
And coupling the inductance
It should be understood that the particular matching structure of the duplexer and multiplexer may be inductively coupled to all pairs of ground of the resonator network Res, or to at least one pair of ground of the resonator network Res.
Next, referring to fig. 5, the improvement of the out-of-band rejection of the specific matching structure of the embodiment of the present disclosure is described, where a thick line is an out-of-band rejection curve corresponding to the structure of the embodiment of the present disclosure, a thin line is an out-of-band rejection curve of a comparative example, with the specific matching structure of the embodiment of the present disclosure (c' having a value of 0.03), both the series inductance and the parallel capacitance have a certain rejection effect, and with the combined structure, the out-of-band rejection is significantly improved. This is because the series inductance is a low pass device, and Zind = j2 π f L, where Zind is the impedance of the inductance, f is the operating frequency, and L is the inductance value, and Zind is small for low frequencies, where Zind is large for high frequencies, where signals are difficult to pass, and thus, for high frequencies in the far band, the series inductance is suppressive; the shunt capacitance is a low pass device, zcap =1/j2 π f C, where C is the capacitance value, zcap is small for high frequencies, the signal is connected directly to ground through a shunt, zcap is large for low frequencies, the signal is difficult to connect directly to ground, and shunt capacitance is suppressive for high frequency signals. Therefore, by incorporating a specific matching network as shown in fig. 2 in the circuits of fig. 3 a-3 e, high frequency signals can be effectively suppressed.
It is desirable to reduce return loss while suppressing high frequency signals. Next, the effect of different values of the capacitance c' on the return loss in certain matching structures of embodiments of the present disclosure is described with reference to fig. 6. In fig. 6, the solid line is an echo curve with a c 'value of 0.03, and the dotted line is an echo curve with a c' value of 0.01. It can be seen that different curves of c 'values have a greater effect on the echo, with the echo being better when c' is within the range of the disclosed embodiment (i.e., 0.01-0.03) and worse outside the range of the disclosed embodiment.
In one embodiment, the inductance value of the inductor is L (in H), the capacitance value of the capacitor is C (in F), and the center frequency of the filter is F (in Hz) for a particular matching structure; for a duplexer, including a transmit filter and a receive filter, the mean of the center frequencies of the transmit filter and the receive filter is f, wherein the center frequency indicates the operating frequency during; for a multiplexer including more filters, the mean value of the center frequencies of the filters is f, in which case the inductance-capacitance and the center frequency satisfy the following formula: l C f = C ', wherein C ' ranges from 0.01 to 0.05, and more preferably, C ' ranges from 0.02 to 0.04, which has better matching characteristics and can improve return loss performance. Specifically, as shown in fig. 6, when c '=0.03, the echo is good, 0.03 is located between 0.02 and 0.04, and when c' is less than 0.01 or greater than 0.05, the echo becomes poor.
Next, the improvement of out-of-band rejection by the coupling structure of the embodiment of the present disclosure is described with reference to fig. 7, where a thick line is an out-of-band rejection curve corresponding to the added coupling, and a thin line is an out-of-band rejection curve not added with the coupling. Where the added coupling M =5pH, it can be seen that the out-of-band rejection is significantly improved in the second half of the frequency range.
Thus, the inductance in a particular matching structure couples with the ground inductance of the transmit filter and/or the receive filter, which may adjust the position of the out-of-band transmission zero to improve rejection at the target frequency.
Further, as can be appreciated by one skilled in the art, filters according to the present disclosure may be used to form filters or electronic devices. The electronic device includes, but is not limited to, intermediate products such as a radio frequency front end and a filtering amplification module, and terminal products such as a mobile phone, WIFI and an unmanned aerial vehicle, or other communication equipment products such as a communication base station and a router.
Based on the above, the embodiments of the present disclosure propose the following solutions:
1. a filter circuit comprising a resonator network and comprising a specific matching structure at least one signal terminal, the specific matching structure comprising an inductive device and a capacitive device.
2. The filter circuit of claim 1, wherein the specific matching structures are series inductive devices and parallel capacitive devices.
3. The filter circuit of claim 2, wherein the series inductive devices and the parallel capacitive devices are connected in a particular order, and wherein the inductive devices are closer to the resonator network than the capacitive devices.
4. The filter circuit of any of claims 1-3, further comprising first and second matching structures located across the resonator network, and one of the first and second matching structures is the particular matching structure.
5. The filter circuit of any of claims 1-3, comprising at least one transmit filter circuit and at least one receive filter circuit, the at least one transmit filter circuit and the at least one receive filter circuit comprising the resonator network;
the transmission filter circuit and the reception filter circuit are connected via a common terminal; and is
The signal output of the transmit filter circuit includes the particular matching structure.
6. The filter circuit of claim 5, further comprising a third matching structure, the transmit filter circuit and receive filter circuit being connected to the third matching structure via a common terminal, and the third matching structure being the particular matching structure.
7. The filter circuit of claim 5, the transmit filter circuit further comprising first and second matching structures located across the resonator network, and one of the first and second matching structures near the common end being the particular matching structure.
8. The filter circuit of claim 5, wherein the particular matching structure is located on a side of the common terminal that is proximate to the transmit filter circuit, or,
the specific matching structure is located on a side of the common terminal away from the transmit filter circuit.
9. The filter circuit of claim 5, wherein one of the series inductive device and the parallel capacitive device of the particular matching structure is located on a side of the common terminal closer to the transmit filter circuit, and the other is located on a side of the common terminal farther from the transmit filter circuit.
10. The filter circuit according to any of claims 1-3 or 6-9, wherein the resonator networks comprise an inductance to ground and the inductive device of the specific matching structure is coupled to the inductance to ground of at least one of the resonator networks.
The filter circuit according to any of claims 1-4 or 4-9, wherein the inductance L of the series inductive device and the capacitance C of the parallel capacitive device of the specific matching structure satisfy the following condition:
L*C*f＝c’，
wherein c' ranges from 0.01 to 0.05; or c' ranges from 0.02 to 0.04; or c' =0.03; and is
Wherein the inductance value L is given in units of H, the capacitance value C is given in units of F, F is the center frequency of the filter, and is given in units of Hz, which represents the multiplication.
12. The filter circuit according to any of claims 4-9, wherein the filter circuit is a duplexer or a multiplexer, and the inductive device of the specific matching structure is an inductor and/or the capacitive device is a capacitor.
13. A filter comprising a filter circuit according to any one of claims 1-12.
14. An electronic device comprising the filter circuit according to any one of claims 1-12 or comprising the filter according to 13.
It should be understood that in the embodiments of the present disclosure, a capacitor may include any other device having a capacitive property at a center frequency, and an inductor may also include any other device having an inductive property at a center frequency, and is not limited to a capacitor and an inductor. In addition, the inductor and the capacitor may be integrated devices, such as integrated devices realized by IPD, LTCC, HTCC, or discrete devices, such as discrete inductor and discrete capacitor devices of SMD, or may be partially integrated devices and partially discrete devices.
The above description is only for the specific embodiments of the present disclosure, but the scope of the present disclosure is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present disclosure should be covered within the scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.
Claims (14)
1. A filter circuit, characterized in that the filter circuit comprises a resonator network and that the filter circuit comprises a specific matching structure at least one signal terminal, the specific matching structure comprising an inductive device and a capacitive device.
2. The filter circuit of claim 1, wherein the specific matching structure is an inductive device in series and a capacitive device in parallel.
3. The filter circuit of claim 2, wherein the series inductive device and the parallel capacitive device are connected in a particular order, and wherein the inductive device is closer to the resonator network than the capacitive device.
4. The filter circuit of any of claims 1-3, further comprising a first matching structure and a second matching structure located across the resonator network, and wherein one of the first matching structure and the second matching structure is the particular matching structure.
5. The filter circuit of any of claims 1-3,
the filter circuit includes at least one transmit filter circuit and at least one receive filter circuit, the at least one transmit filter circuit and the at least one receive filter circuit including the resonator network;
the transmission filter circuit and the reception filter circuit are connected via a common terminal; and is provided with
The signal output of the transmit filter circuit includes the particular matching structure.
6. The filter circuit of claim 5, further comprising a third matching structure, wherein the transmit filter circuit and the receive filter circuit are connected to the third matching structure via a common terminal, and wherein the third matching structure is the particular matching structure.
7. The filter circuit of claim 5, wherein the transmit filter circuit further comprises a first matching structure and a second matching structure located across the resonator network, and wherein one of the first matching structure and the second matching structure near the common end is the particular matching structure.
8. The filter circuit of claim 5,
the specific matching structure is located on a side of the common terminal close to the transmit filter circuit, or,
the specific matching structure is located on a side of the common terminal away from the transmit filter circuit.
9. The filter circuit of claim 5, wherein one of the series inductive device and the parallel capacitive device of the specific matching structure is located on a side of the common terminal close to the transmit filter circuit, and the other is located on a side of the common terminal far from the transmit filter circuit.
10. The filter circuit of any of claims 1-3 or 6-9, wherein the resonator networks comprise a ground inductance and the inductive device of the particular matching structure is inductively coupled to the ground of at least one of the resonator networks.
11. The filter circuit according to any of claims 1-4 or 4-9, wherein the inductance L of the series inductive element and the capacitance C of the parallel capacitive element of the specific matching structure satisfy the following condition:
L*C*f＝c’，
wherein c' ranges from 0.01 to 0.05; or c' ranges from 0.02 to 0.04; or c' =0.03; and is
Wherein the inductance value L is given in units of H, the capacitance value C is given in units of F, F is the center frequency of the filter, and is given in units of Hz, which represents the multiplication.
12. A filter circuit according to any one of claims 4-9, characterized in that the filter circuit is a duplexer or a multiplexer and the inductive device of the specific matching structure is an inductance and/or the capacitive device is a capacitance.
13. A filter comprising a filter circuit according to any one of claims 1-12.
14. An electronic device comprising a filter circuit according to any one of claims 1-12 or comprising a filter according to claim 13.
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| CN202211285975.4A CN115567031A (en) | 2022-10-20 | 2022-10-20 | Filter circuit comprising matching structure |
| CN202310801493.8A CN116743109A (en) | 2022-10-20 | 2023-07-03 | Filter circuit comprising matching structure |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103259501A (en) * | 2013-05-31 | 2013-08-21 | 电子科技大学 | Band elimination filter for communication system |
| US20210028770A1 (en) * | 2019-07-12 | 2021-01-28 | U.S. Army Combat Capabilities Development Command, Army Research Laboratory | Active matching network design for electrically small resonant antennas |
| CN112491386A (en) * | 2020-11-18 | 2021-03-12 | 浙江信唐智芯科技有限公司 | Micro-electro-mechanical system filter |
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2022
- 2022-10-20 CN CN202211285975.4A patent/CN115567031A/en active Pending
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103259501A (en) * | 2013-05-31 | 2013-08-21 | 电子科技大学 | Band elimination filter for communication system |
| US20210028770A1 (en) * | 2019-07-12 | 2021-01-28 | U.S. Army Combat Capabilities Development Command, Army Research Laboratory | Active matching network design for electrically small resonant antennas |
| CN112491386A (en) * | 2020-11-18 | 2021-03-12 | 浙江信唐智芯科技有限公司 | Micro-electro-mechanical system filter |
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