Multiplexer

Abstract

The present disclosure provides a multiplexer. The multiplexer according to the present disclosure includes: at least one transmit filter and at least one receive filter commonly coupled to an antenna node, the transmit filter and the receive filter both include a series resonance unit and a parallel resonance unit, wherein the electromechanical coupling coefficient of the series and parallel resonance units of the transmit filter is higher than the electromechanical coupling coefficient of the series and parallel resonance units of the receive filter, or the electromechanical coupling coefficient of at least one series resonance unit of the transmit filter is higher than the electromechanical coupling coefficient of the series and parallel resonance units of the receive filter, or the electromechanical coupling coefficient of at least one series resonance unit of the transmit filter and the electromechanical coupling coefficient of the parallel resonance unit of the receive filter are higher than the electromechanical coupling coefficient of the series resonance unit of the receive filter. According to the present disclosure, a multiplexer with high insertion loss and high isolation can be realized without adding additional components or manufacturing process steps.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electronic circuits, and in particular, to a multiplexer. Background Art

[0002] With the development of wireless communication applications, people have higher and higher requirements for data transmission rates. Corresponding to the data transmission rate is the high utilization of spectrum resources and the complexity of the spectrum. The complexity of communication protocols has put forward strict requirements on the various performances of RF systems. In RF front-end modules, multiplexers play a vital role. With the increase in 5G commercial use, the demand for multiplexers such as B1, B2, B3, B5, B7, and B8 is also increasing.

[0003] Currently, multiplexers based on acoustic resonators are increasingly being used due to their advantages such as steep edge roll-off characteristics, high selectivity, high power capacity, and strong anti-electrostatic discharge (ESD) capability.

[0004] The acoustic resonators used in the transmit (Tx) filter and receive (Rx) filter in the current multiplexer usually use the same type of piezoelectric material such as AlN or AlN doped with other elements, so that these acoustic resonators have the same or similar electromechanical coupling coefficients. However, the electromechanical coupling coefficient of the acoustic resonator using AlN as the piezoelectric material is insufficient to meet the high insertion loss of the Tx filter (low-frequency filter) in the multiplexer and the high isolation requirements for the Rx frequency band. In addition, although the electromechanical coupling coefficient of the acoustic resonator using doped AlN as the piezoelectric material is improved, the series resonance frequency of the parallel resonance unit of the Rx filter (high-frequency filter) in the multiplexer falls into the Tx frequency band (low-frequency band), which makes it easy to produce a depression in the Tx passband.

[0005] In order to solve the above problems, in the prior art, an impedance matching tuning unit is usually added to improve the isolation while ensuring high insertion loss, or an inductor or capacitor is connected in parallel in the series resonant unit connected to the antenna node. However, these improvement schemes increase the difficulty of design and integration, and are not easy to miniaturize the multiplexer.

[0006] Therefore, there is still a need in the prior art for a multiplexer that can achieve high insertion loss and high isolation without adding additional components or manufacturing process steps. Summary of the invention

[0007] A brief summary of the disclosure is given below in order to provide a basic understanding of certain aspects of the disclosure. However, it should be understood that this summary is not an exhaustive summary of the disclosure, nor is it intended to identify the key or important parts of the disclosure, nor is it intended to limit the scope of the disclosure. The purpose of this summary is only to present certain inventive concepts of the disclosure in a simplified form as a prelude to a more detailed description given later.

[0008] The object of the present disclosure is to provide a multiplexer that can achieve high insertion loss and high isolation without adding additional components or manufacturing process steps.

[0009] According to one aspect of the present disclosure, a multiplexer is provided, comprising: at least one transmit filter, an output node of which is coupled to an antenna node and comprises a series resonance unit and a parallel resonance unit; and at least one receive filter, an input node of which is coupled to an antenna node and comprises a series resonance unit and a parallel resonance unit, wherein the series resonance unit and the parallel resonance unit of the transmit filter have substantially the same first electromechanical coupling coefficient, and the series resonance unit and the parallel resonance unit of the receive filter have substantially the same second electromechanical coupling coefficient, wherein the first electromechanical coupling coefficient is higher than the second electromechanical coupling coefficient.

[0010] According to an embodiment of the present disclosure, the difference between the first electromechanical coupling coefficient and the second electromechanical coupling coefficient is greater than one tenth of the first electromechanical coupling coefficient.

[0011] According to an embodiment of the present disclosure, the first electromechanical coupling coefficient is in the range of 7% to 20%, and the second electromechanical coupling coefficient is in the range of 5% to 15%. Preferably, the first electromechanical coupling coefficient is in the range of 7.5% to 8.5%, and the second electromechanical coupling coefficient is in the range of 5% to 6.8%.

[0012] According to another aspect of the present disclosure, a multiplexer is provided, comprising: at least one transmit filter, an output node of which is coupled to an antenna node and includes a series resonance unit and a parallel resonance unit; and at least one receive filter, an input node of which is coupled to the antenna node and includes a series resonance unit and a parallel resonance unit, wherein at least one series resonance unit of the transmit filter has a third electromechanical coupling coefficient, and the series resonance unit and the parallel resonance unit of the receive filter have substantially the same fourth electromechanical coupling coefficient, and the third electromechanical coupling coefficient is higher than the fourth electromechanical coupling coefficient.

[0013] According to an embodiment of the present disclosure, the difference between the third electromechanical coupling coefficient and the fourth electromechanical coupling coefficient is greater than one tenth of the third electromechanical coupling coefficient.

[0014] According to an embodiment of the present disclosure, at least one series resonance unit of the transmit filter having the third electromechanical coupling coefficient is directly coupled to the output node of the transmit filter.

[0015] According to an embodiment of the present disclosure, the series resonance units and the parallel resonance units of the transmit filter except for the at least one series resonance unit having the third electromechanical coupling coefficient have substantially the same fifth electromechanical coupling coefficient.

[0016] According to another aspect of the present disclosure, a multiplexer is provided, comprising: at least one transmit filter, an output node of which is coupled to an antenna node and comprises a series resonance unit and a parallel resonance unit; and at least one receive filter, an input node of which is coupled to the antenna node and comprises a series resonance unit and a parallel resonance unit, wherein at least one series resonance unit of the transmit filter has a sixth electromechanical coupling coefficient, the series resonance unit of the receive filter has a substantially same seventh electromechanical coupling coefficient, and the parallel resonance unit of the receive filter has a substantially same eighth electromechanical coupling coefficient, and the sixth electromechanical coupling coefficient and the eighth electromechanical coupling coefficient are higher than the seventh electromechanical coupling coefficient.

[0017] According to an embodiment of the present disclosure, the difference between the sixth electromechanical coupling coefficient and the seventh electromechanical coupling coefficient is greater than one tenth of the sixth electromechanical coupling coefficient, and the difference between the eighth electromechanical coupling coefficient and the seventh electromechanical coupling coefficient is greater than one tenth of the eighth electromechanical coupling coefficient.

[0018] According to an embodiment of the present disclosure, at least one series resonance unit of the transmit filter having the sixth electromechanical coupling coefficient is directly coupled to the output node of the transmit filter.

[0019] According to an embodiment of the present disclosure, the series resonance units and the parallel resonance units of the transmit filter except for the at least one series resonance unit having the sixth electromechanical coupling coefficient have substantially the same ninth electromechanical coupling coefficient.

[0020] According to an embodiment of the present disclosure, the series resonance unit and the parallel resonance unit of the transmit filter and / or the receive filter are connected in a ladder configuration.

[0021] According to an embodiment of the present disclosure, for each of the transmitting filter and the receiving filter, a series resonance unit is connected in series between an input node and an output node of the corresponding filter, and a parallel resonance unit is connected in parallel between a connection node and a ground node, and the connection node is a node at the input end and / or output end of the series resonance unit.

[0022] According to an embodiment of the present disclosure, the parallel resonance unit includes a resonator and an inductor connected in series between a connection node and a ground node.

[0023] According to an embodiment of the present disclosure, the series resonance unit and / or the parallel resonance unit of the transmit filter and / or the receive filter includes a resonator, which is a surface acoustic resonator, a film bulk acoustic resonator, a solid-state assembly acoustic resonator or a Lamb wave resonator.

[0024] According to an embodiment of the present disclosure, the electromechanical coupling coefficient is adjusted by changing the piezoelectric material of the resonator or adjusting the doping element, doping concentration and / or doping combination of the piezoelectric material of the resonator.

[0025] According to an embodiment of the present disclosure, the electromechanical coupling coefficient is adjusted by changing the type of resonator.

[0026] According to an embodiment of the present disclosure, a part of the series resonance unit and / or the parallel resonance unit of the transmit filter and / or the receive filter includes a resonance unit composed of a capacitive element and an inductive element. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate embodiments of the present disclosure and together with the following description serve to explain the principles of the present disclosure.

[0028] Figure 1 An equivalent circuit diagram of a duplexer according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0029] In this specification, it will also be understood that when an element is referred to as being relative to other elements, such as being "on", "connected to" or "coupled to" other elements, the one element may be directly disposed on, directly connected to or directly coupled to the one element, or there may also be a third element in between. Conversely, when an element is referred to as being relative to other elements, such as being "directly" "on", "directly connected to" or "directly coupled to" other elements in this specification, no intervening elements are disposed therebetween.

[0030] The present disclosure will now be described more fully below with reference to the accompanying drawings, in which various embodiments are shown. However, the present disclosure can be implemented in many different ways and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be exhaustive and complete, and will fully convey the scope of the present disclosure to those skilled in the art. The same reference numerals throughout the text represent the same elements. Furthermore, in the accompanying drawings, the thickness, ratios, and sizes of the components are exaggerated for clarity.

[0031] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, "one", "the", and "at least one" as used herein do not represent a limitation on quantity, but are intended to include both the singular and the plural. For example, unless the context clearly indicates otherwise, "an element" has the same meaning as "at least one element". "At least one" should not be interpreted as being limited to the number "one". "Or" means "and / or". The term "and / or" includes any and all combinations of at least one of the associated listed items.

[0032] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meanings as those generally understood by those skilled in the art. Terms defined in commonly used dictionaries should be interpreted as having the same meanings as in the relevant technical context, and unless explicitly defined in the specification, these terms are not interpreted as having formal meanings in an idealized or overly formal sense.

[0033] The meaning of “include” or “comprising” specifies properties, quantities, steps, operations, elements, parts or their combinations, but does not exclude other properties, quantities, steps, operations, elements, parts or their combinations.

[0034] Hereinafter, exemplary embodiments according to the present disclosure will be described with reference to the accompanying drawings.

[0035] Figure 1 FIG. 1 shows an equivalent circuit diagram of a duplexer 100 according to an embodiment of the present disclosure. A person skilled in the art should recognize that the “multiplexer” referred to herein includes multiple types of devices such as duplexers, triplexers, and quadplexers. Therefore, although Figure 1 The multiplexer disclosed in the present invention is described by taking a duplexer as an example, but based on Figure 1 The duplexer shown can be easily extended to other types of multiplexers such as triplexers and quadplexers by those skilled in the art. Since these extension technologies are known to those skilled in the art, for the sake of brevity, the details thereof are not described in more detail herein.

[0036] like Figure 1 As shown, the duplexer 100 may include a transmit (Tx) filter 110 and a receive (Rx) filter 120 .

[0037] As described above, by adding more Tx filters and / or Rx filters, the duplexer 100 can be easily expanded to other types of multiplexers such as a triplexer and a quadplexer, and all of these expansion schemes should be included in the scope of the present disclosure.

[0038] like Figure 1As shown, the output node NTxout of the Tx filter 110 is coupled to the antenna node Nt, and includes a series resonant unit and a parallel resonant unit connected in a ladder configuration. Figure 1 As shown, the antenna node Nt may be connected to an inductor Lt as an impedance matching unit.

[0039] Those skilled in the art will recognize that although Figure 1 In the embodiment of the present disclosure, the Tx filter 110 is a 3-step ladder filter, which includes the first to third series resonance units S1101 to S1103 and the first to third parallel resonance units P1101 to P1103, but the present disclosure is not limited thereto. According to the embodiments of the present disclosure, the Tx filter 110 may be a ladder filter of any order or a filter having other topological structures, and may include any number of series resonance units and parallel resonance units, and all these variations shall be included within the scope of the present disclosure.

[0040] like Figure 1 As shown, the first to third series resonant units S1101 to S1103 are sequentially connected in series between the output node NTxout and the input node NTxin of the Tx filter 110. In addition, an output impedance matching unit (not shown) may be connected in series and / or in parallel between the output node NTxout and the first series resonant unit S1101, and an output impedance matching unit (not shown) may be connected in series and / or in parallel between the third series resonant unit S1103 and the input node NTxin. The input impedance matching unit and the output impedance matching unit may include impedance matching elements such as inductors, capacitors, resonators, or matching units formed by them.

[0041] In addition, if Figure 1 As shown, the first to third parallel resonant units P1101 to P1103 are connected in parallel between connection nodes N1101 to N1103 and the ground node GND, and the connection nodes N1101 to N1103 are nodes at the input and / or output ends of the first to third series resonant units S1101 to S1103.

[0042] In addition, if Figure 1 As shown, the input node NRxin of the Rx filter 120 is coupled to the antenna node Nt, and includes a series resonant unit and a parallel resonant unit connected in a ladder configuration.

[0043] Those skilled in the art will recognize that although Figure 1In the embodiment of the present disclosure, the Rx filter 120 is a 3-step ladder filter, which includes the first to third series resonance units S1201 to S1203 and the first to third parallel resonance units P1201 to P1203, but the present disclosure is not limited thereto. According to the embodiment of the present disclosure, the Rx filter 120 may be a ladder filter of any order or a filter having other topological structures, and may include any number of series resonance units and parallel resonance units, and all these variations should be included in the scope of the present disclosure.

[0044] In addition, despite the Figure 1 In the embodiment of the present disclosure, the Rx filter 120 has the same circuit topology as the Tx filter 110, that is, both are 3-order ladder filters, but the present disclosure is not limited thereto. According to the embodiments of the present disclosure, the Rx filter 120 may have a circuit topology different from that of the Tx filter 110, that is, it may be a ladder filter of other orders other than the 3rd order or a filter with other circuit topologies, and all these variants shall be included in the scope of the present disclosure.

[0045] like Figure 1 As shown, the first to third series resonant units S1201 to S1203 are sequentially connected in series between the input node NRxin and the output node NRxout of the Rx filter 120. In addition, an input impedance matching unit (not shown) may be connected in series and / or in parallel between the input node NRxin and the first series resonant unit S1201, and an output impedance matching unit (not shown) may be connected in series and / or in parallel between the third series resonant unit S1203 and the output node NRxout. The input impedance matching unit and the output impedance matching unit may include impedance matching elements such as inductors, capacitors, resonators, or matching units formed by them.

[0046] In addition, if Figure 1 As shown, the first to third parallel resonant units P1201 to P1203 are connected in parallel between connection nodes N1201 to N1203 and a ground node GND, and the connection nodes N1201 to N1203 are nodes at the input and / or output ends of the first to third series resonant units S1201 to S1203.

[0047] In addition, those skilled in the art should recognize that although the Tx filter 110 and the Rx filter 120 according to the embodiment of the present disclosure are described herein by taking the ladder filter as an example, the present disclosure is not limited thereto. According to the teachings of the present disclosure, those skilled in the art can easily imagine applying the inventive concept of the present disclosure to multiplexers based on other filter circuit topologies other than the ladder filter.

[0048] The first to third series resonant units S1101 to S1103 and the first to third parallel resonant units P1101 to P1103 of the Tx filter 110 and the first to third series resonant units S1201 to S1203 and the first to third parallel resonant units P1201 to P1203 of the Rx filter 120 may be collectively referred to herein as "resonant units". Those skilled in the art should recognize that the "resonant unit" referred to herein may be composed of a single resonator or a series and / or parallel circuit of a resonator and an inductor and / or a capacitor. For example, each of the first to third parallel resonant units P1101 to P1103 of the Tx filter 110 and the first to third parallel resonant units P1201 to P1203 of the Rx filter 120 may be composed of a resonator and an inductor connected in series between a connection node and a ground node. In addition, those skilled in the art should recognize that the "resonant unit" referred to herein may also include a resonant unit composed of a capacitive element such as a capacitor and an inductive element such as an inductor. All such variations are intended to fall within the scope of this disclosure.

[0049] Therefore, those skilled in the art should understand that the electromechanical coupling coefficient of the resonance unit recorded in this article can be regarded as the electromechanical coupling coefficient of the resonator included in the resonance unit. In other words, in this article, "electromechanical coupling coefficient of the resonance unit" and "electromechanical coupling coefficient of the resonator" have the same technical meaning.

[0050] According to an embodiment of the present disclosure, the resonator of each resonant unit constituting the Tx filter 110 and the Rx filter 120 may be an acoustic resonator, such as a surface acoustic resonator, a film bulk acoustic resonator, a solid-state assembly acoustic resonator, or a Lamb wave resonator. An acoustic resonator generally has a sandwich structure of a lower electrode, a piezoelectric layer, and an upper electrode prepared on a substrate, wherein the piezoelectric layer is made of a piezoelectric material having an electromechanical conversion capability, such as AlN or doped AlN, for realizing the conversion between an acoustic signal (acoustic wave) and an electrical signal. The figure of merit FOM of a piezoelectric material and an acoustic resonator using the piezoelectric material is given by the electromechanical coupling coefficient kt 2 It is determined together with the quality factor Q, that is, FOM = kt 2 *Q, where the electromechanical coupling coefficient characterizes the coupling and conversion ability between acoustic energy and electrical energy of the piezoelectric material, and its value is proportional to the bandwidth of the working frequency band. Since the acoustic resonator is known to those skilled in the art, for the sake of brevity, this article will not describe its details in more detail.

[0051] The inventive concept of the present disclosure is to realize a multiplexer with high insertion loss and high isolation by adjusting the electromechanical coupling coefficient of each resonant unit of the Tx filter and the Rx filter included in the multiplexer without adding additional components or manufacturing process steps.

[0052] According to the first embodiment of the present disclosure, the first to third series resonant units S1101 to S1103 and the first to third parallel resonant units P1101 to P1103 of the Tx filter 110 have substantially the same first electromechanical coupling coefficient, and the first to third series resonant units S1201 to S1203 and the first to third parallel resonant units P1201 to P1203 of the Rx filter 120 have substantially the same second electromechanical coupling coefficient, wherein the first electromechanical coupling coefficient is higher than the second electromechanical coupling coefficient. It should be noted that the term "substantially the same" herein means that the numerical difference between the two is within a reasonable error range, preferably within a relative error of 5%.

[0053] According to the first embodiment of the present disclosure, the difference between the first electromechanical coupling coefficient and the second electromechanical coupling coefficient is greater than one tenth of the first electromechanical coupling coefficient.

[0054] According to a first embodiment of the present disclosure, the first electromechanical coupling coefficient is in the range of 7% to 20%, and the second electromechanical coupling coefficient is in the range of 5% to 15%. Preferably, the first electromechanical coupling coefficient is in the range of 7.5% to 8.5%, and the second electromechanical coupling coefficient is in the range of 5% to 6.8%.

[0055] According to the embodiments of the present disclosure, a larger first electromechanical coupling coefficient can improve the insertion loss of the Tx filter and reduce the inductance value of the series inductor required for the parallel resonance unit; at the same time, a smaller second electromechanical coupling coefficient can reduce the impact of the parallel resonance unit of the Rx filter on the insertion loss of the Tx filter. Therefore, setting the first electromechanical coupling coefficient higher than the second electromechanical coupling coefficient can achieve the technical effect of improving insertion loss and isolation.

[0056] According to a second embodiment of the present disclosure, at least one of the first to third series resonant units S1101 to S1103 of the Tx filter 110 has a third electromechanical coupling coefficient, and the first to third series resonant units S1201 to S1203 and the first to third parallel resonant units P1201 to P1203 of the Rx filter 120 have substantially the same fourth electromechanical coupling coefficient, wherein the third electromechanical coupling coefficient is higher than the fourth electromechanical coupling coefficient.

[0057] According to the second embodiment of the present disclosure, the difference between the third electromechanical coupling coefficient and the fourth electromechanical coupling coefficient is greater than one tenth of the third electromechanical coupling coefficient.

[0058] Furthermore, according to the second embodiment of the present disclosure, at least one series resonance unit of the Tx filter 110 having the third electromechanical coupling coefficient is a first series resonance unit S1101 , ie, a series resonance unit directly coupled to the output node NTxout of the Tx filter 110 .

[0059] According to the second embodiment of the present disclosure, the Tx filter 110 has a series resonance unit (eg, the first series resonance unit S1101 ) with a large electromechanical coupling coefficient, which can help improve the insertion loss at high frequencies of the Tx filter 110 and the Rx filter 120 .

[0060] In addition, according to the second embodiment of the present disclosure, the second and third series resonance units S1102 and S1103 and the first to third parallel resonance units P1101 to P1103 of the Tx filter 110 except for at least one series resonance unit, namely, the first series resonance unit S1101, have substantially the same fifth electromechanical coupling coefficient.

[0061] According to a third embodiment of the present disclosure, at least one of the first to third series resonant units S1101 to S1103 of the Tx filter 110 has a sixth electromechanical coupling coefficient, the first to third series resonant units S1201 to S1203 of the Rx filter 120 have substantially the same seventh electromechanical coupling coefficient, and the first to third parallel resonant units P1201 to P1203 of the Rx filter 120 have substantially the same eighth electromechanical coupling coefficient, wherein the sixth electromechanical coupling coefficient and the eighth electromechanical coupling coefficient are higher than the seventh electromechanical coupling coefficient.

[0062] According to the third embodiment of the present disclosure, the difference between the sixth electromechanical coupling coefficient and the seventh electromechanical coupling coefficient is greater than one tenth of the sixth electromechanical coupling coefficient, and the difference between the eighth electromechanical coupling coefficient and the seventh electromechanical coupling coefficient is greater than one tenth of the eighth electromechanical coupling coefficient.

[0063] Furthermore, according to the third embodiment of the present disclosure, at least one series resonance unit of the Tx filter 110 having the sixth electromechanical coupling coefficient is a first series resonance unit S1101 , ie, a series resonance unit directly coupled to the output node NTxout of the Tx filter 110 .

[0064] According to the third embodiment of the present disclosure, the Tx filter 110 has a series resonance unit (eg, the first series resonance unit S1101 ) with a large electromechanical coupling coefficient, which can help improve the insertion loss at high frequencies of the Tx filter 110 and the Rx filter 120 .

[0065] In addition, according to the third embodiment of the present disclosure, the second and third series resonance units S1102 and S1103 and the first to third parallel resonance units P1101 to P1103 of the Tx filter 110 except for at least one series resonance unit, namely, the first series resonance unit S1101, have substantially the same ninth electromechanical coupling coefficient.

[0066] According to the above embodiments of the present disclosure, the first, third, sixth and eighth electromechanical coupling coefficients can be regarded as high electromechanical coupling coefficients, and the second, fourth, fifth, seventh and ninth electromechanical coupling coefficients can be regarded as low electromechanical coupling coefficients. According to an embodiment of the present disclosure, the high electromechanical coupling coefficient is in the range of 7% to 20%, and the low electromechanical coupling coefficient is in the range of 5% to 15%. Preferably, the high electromechanical coupling coefficient is in the range of 7.5% to 8.5%, and the low electromechanical coupling coefficient is in the range of 5% to 6.8%.

[0067] According to an embodiment of the present disclosure, the resonance units of the Tx filter 110 and the Rx filter 120 may be composed of resonators. According to an embodiment of the present disclosure, the electromechanical coupling coefficient is adjusted by changing the piezoelectric material of the resonator or adjusting the doping element, doping concentration and / or doping combination of the piezoelectric material of the resonator.

[0068] According to an embodiment of the present disclosure, the piezoelectric material of the resonator may include but is not limited to: a wurtzite structure, such as AlN, ZnO; a perovskite structure, such as BaTiO3, Pb(Ti,Zr)O3, Li(Nb,Ta)O3, or (K,Na)NbO3; and an organic piezoelectric material, such as polyvinylidene fluoride PVDF, etc.

[0069] According to an embodiment of the present disclosure, the resonator of each resonance unit may have different types of piezoelectric materials, and by changing the piezoelectric material of the resonator, the electromechanical coupling coefficient may be adjusted. For example, in order to obtain a high electromechanical coupling coefficient, Li(Nb, Ta)O3 may be used as a piezoelectric material, and in order to obtain a low electromechanical coupling coefficient, AlN may be used as a piezoelectric material.

[0070] Alternatively or in combination, according to an embodiment of the present disclosure, the resonators of each resonance unit may also have the same type of piezoelectric material. It should be noted that the "same type of piezoelectric material" referred to herein refers to piezoelectric materials with the same matrix, such as AlN or AlN doped with other elements may be regarded as the same type of piezoelectric material in this article. According to an embodiment of the present disclosure, the electromechanical coupling coefficient can be adjusted by adjusting the doping elements, doping concentration and / or doping combination of the piezoelectric material of the resonator.

[0071] As a specific example, if a resonator with a low electromechanical coupling coefficient is desired, the piezoelectric material may be pure AlN, AlN with a low doping concentration, or AlN doped with an element for reducing the electromechanical coupling coefficient. According to an embodiment of the present disclosure, the doping elements for reducing the electromechanical coupling coefficient include, but are not limited to, B, Ga, and In.

[0072] In addition, as a specific example, if it is desired to obtain a resonator with a high electromechanical coupling coefficient, the piezoelectric material can be AlN with a high doping concentration, AlN doped with an element for improving the electromechanical coupling coefficient, or a stack of multiple doped AlN layers with different doping concentrations. According to an embodiment of the present disclosure, the doping elements for improving the electromechanical coupling coefficient include, but are not limited to, Ti, Sc, Mg, Zr, Hf, Sb, Y, Sm, Eu, Er, Ta, and Cr.

[0073] According to an embodiment of the present disclosure, the electromechanical coupling coefficient can also be adjusted by adjusting the type of resonator. For example, in order to obtain a high electromechanical coupling coefficient, a surface acoustic resonator can be used, and in order to obtain a low electromechanical coupling coefficient, a bulk acoustic resonator can be used.

[0074] According to an embodiment of the present disclosure, a part of the resonance units of the Tx filter 110 and the Rx filter 120 may also include a resonance unit composed of a capacitive element such as a capacitor and an inductive element such as an inductor. According to an embodiment of the present disclosure, by adjusting the parameters of the capacitive element and the inductive element constituting the resonance unit, the electromechanical coupling coefficient may also be adjusted.

[0075] According to the above embodiments of the present disclosure, a multiplexer with high insertion loss and high isolation can be realized without adding additional components or manufacturing process steps.

[0076] Although the present disclosure has been described with reference to exemplary embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations may be made without departing from the spirit and scope of the present disclosure as set forth in the claims.

Claims

1. A multiplexer comprising: at least one transmit filter having an output node coupled to the antenna node and comprising a series resonant unit and a parallel resonant unit; as well as at least one receiving filter, whose input node is coupled to the antenna node and includes a series resonant unit and a parallel resonant unit, The series resonant unit and the parallel resonant unit of the transmitting filter have substantially the same first electromechanical coupling coefficient, i.e., a relative error within 5%, and the series resonant unit and the parallel resonant unit of the receiving filter have substantially the same second electromechanical coupling coefficient, i.e., a relative error within 5%, and Wherein, the first electromechanical coupling coefficient is higher than the second electromechanical coupling coefficient.

2. The multiplexer according to claim 1, in, A difference between the first electromechanical coupling coefficient and the second electromechanical coupling coefficient is greater than one tenth of the first electromechanical coupling coefficient.

3. The multiplexer according to claim 1, in, The first electromechanical coupling coefficient is in a range of 7% to 20%, and the second electromechanical coupling coefficient is in a range of 5% to 15%.

4. A multiplexer comprising: at least one transmit filter having an output node coupled to the antenna node and comprising a series resonant unit and a parallel resonant unit; as well as at least one receiving filter, whose input node is coupled to the antenna node and includes a series resonant unit and a parallel resonant unit, wherein at least one series resonance unit of the transmitting filter has a third electromechanical coupling coefficient, and the series resonance unit and the parallel resonance unit of the receiving filter have a fourth electromechanical coupling coefficient that is substantially the same, i.e., a relative error within 5%, and Wherein, the third electromechanical coupling coefficient is higher than the fourth electromechanical coupling coefficient.

5. The multiplexer according to claim 4, in, A difference between the third electromechanical coupling coefficient and the fourth electromechanical coupling coefficient is greater than one tenth of the third electromechanical coupling coefficient.

6. The multiplexer according to claim 4, in, At least one series resonance unit of the transmit filter having the third electromechanical coupling coefficient is directly coupled to an output node of the transmit filter.

7. The multiplexer according to claim 4, in, The series resonant units and parallel resonant units of the transmit filter, except for the at least one series resonant unit having the third electromechanical coupling coefficient, have fifth electromechanical coupling coefficients that are substantially the same, that is, within a relative error of 5%.

8. A multiplexer comprising: at least one transmit filter having an output node coupled to the antenna node and comprising a series resonant unit and a parallel resonant unit; as well as at least one receiving filter, whose input node is coupled to the antenna node and includes a series resonant unit and a parallel resonant unit, wherein at least one series resonant unit of the transmit filter has a sixth electromechanical coupling coefficient, the series resonant unit of the receive filter has a seventh electromechanical coupling coefficient that is substantially the same, i.e., the relative error is within 5%, and the parallel resonant unit of the receive filter has an eighth electromechanical coupling coefficient that is substantially the same, i.e., the relative error is within 5%, and Among them, the sixth electromechanical coupling coefficient and the eighth electromechanical coupling coefficient are higher than the seventh electromechanical coupling coefficient.

9. The multiplexer according to claim 8, in, The difference between the sixth electromechanical coupling coefficient and the seventh electromechanical coupling coefficient is greater than one tenth of the sixth electromechanical coupling coefficient, and the difference between the eighth electromechanical coupling coefficient and the seventh electromechanical coupling coefficient is greater than one tenth of the eighth electromechanical coupling coefficient.

10. The multiplexer according to claim 8, in, At least one series resonance unit of the transmit filter having the sixth electromechanical coupling coefficient is directly coupled to an output node of the transmit filter.

11. The multiplexer according to claim 8, in, The series resonant units and parallel resonant units of the transmit filter, except for the at least one series resonant unit having the sixth electromechanical coupling coefficient, have substantially the same ninth electromechanical coupling coefficient, that is, a relative error within 5%.

12. The multiplexer according to any one of claims 1 to 11, in, The series resonance units and the parallel resonance units of the transmit filter and / or the receive filter are connected in a ladder configuration.

13. The multiplexer according to any one of claims 1 to 11, in, For each of the transmit filter and the receive filter, The series resonant unit is connected in series between the input node and the output node of the corresponding filter, and The parallel resonant unit is connected in parallel between a connection node, which is a node at an input terminal and / or an output terminal of the series resonant unit, and a ground node.

14. The multiplexer according to claim 13, wherein: The parallel resonance unit includes a resonator and an inductor connected in series between the connection node and the ground node.

15. The multiplexer according to any one of claims 1 to 11, in, The series resonance unit and / or the parallel resonance unit of the transmit filter and / or the receive filter includes a resonator, and the resonator is a surface acoustic resonator, a film bulk acoustic resonator, a solid-state assembly bulk acoustic resonator or a Lamb wave resonator.

16. The multiplexer according to claim 15, in, The electromechanical coupling coefficient is adjusted by changing the piezoelectric material of the resonator or adjusting the doping element, doping concentration and / or doping combination of the piezoelectric material of the resonator.

17. The multiplexer according to claim 15, in, The electromechanical coupling coefficient is adjusted by changing the type of the resonator.

18. The multiplexer according to any one of claims 1 to 11, in, A part of the series resonance unit and / or the parallel resonance unit of the transmit filter and / or the receive filter includes a resonance unit composed of a capacitive element and an inductive element.

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