RF receive filters, RF duplexers and RF multiplexers

Abstract

RF receive filter (RX filter) (Rx), comprising an input port (A) for receiving a high-frequency signal from an antenna and an output port (R) for providing the filtered high-frequency signal, and a cascade circuit of an acoustic bulk wave (BAW) filter section (BAW_f), an acoustic surface wave (SAW) filter section (SAW_f) with at least one SAW resonator and a dual-mode SAW filter (DMS filter) (DMS), wherein - the BAW filter section (BAW_f) includes at least one BAW resonator and is located on an input side of the RX filter (Rx), - the SAW filter section (SAW_f) includes at least one SAW resonator and is located on an output side of the RX filter (Rx), and - the DMS filter (DMS) is located between the BAW filter section (BAW_f) and the SAW filter section (SAW_f), wherein acoustic structures (AS) of the BAW filter section (BAW_f) and acoustic structures (AS) of the SAW filter section (SAW_f) and acoustic structures (AS) of the DMS filter (DMS) are arranged on a single die, wherein the acoustic structures (AS) of the BAW filter section (BAW_f) are arranged on a first surface of the die and the acoustic structures (AS) of the SAW filter section (SAW_f) and the DMS filter (DMS) are arranged on a surface opposite the first surface.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an RF reception filter. The present disclosure also relates to an RF duplexer, an RF multiplexer, and an RF filter device comprising the RF reception filter. BACKGROUND

[0002] Carrier aggregation is a technique used in wireless communications to increase the data rate per user. This technique assigns multiple frequency blocks, also known as component carriers, to the same user. The overall data rate of a cell is also increased due to better resource utilization. Additionally, load balancing is possible with carrier aggregation.

[0003] Such applications require radio-frequency (RF) filters. RF filters typically require many design compromises to achieve the best balance between performance parameters such as insertion loss, rejection, isolation, power handling, linearity, size, and cost for each specific application.

[0004] Electroacoustic resonators are widely used in electronic devices to implement RF filters, including band-rejection filters, band-pass filters, duplexers and multiplexers, oscillators, and other frequency-selective electronic components. The resonators comprise a pair of electrodes and a piezoelectric layer. Applying an RF electrical signal to the electrodes generates a resonating acoustic wave within the piezoelectric layer, which is frequency-selective with respect to the RF electrical signal. An electronic RF filter can be formed by connecting several electroacoustic resonators together, which can select a desired frequency band from the received frequency spectrum or the shape of an electrical signal for transmission.

[0005] Several types of electroacoustic resonators are available, such as bulk acoustic wave (BAW) resonators, in which the piezoelectric layer is sandwiched between a pair of lower and upper electrodes, and surface acoustic wave (SAW) resonators, which include a pair of interdigital transducer electrodes on the upper surface of the piezoelectric layer.

[0006] The published patent application DE 10 2012 108 035 A1 relates to capacitors with improved linear behavior, e.g., for high-frequency (HF) circuits. A capacitor comprises a first and a second electrically conductive layer. The capacitor further comprises a first and a second electrode structured in the first layer and a third electrode structured in the second layer. A dielectric layer is arranged between the electrically conductive layers. A portion of the first electrode and a portion of the second electrode each overlap at least a portion of the third electrode. The first electrode and the second electrode are the terminal electrodes of the capacitor.

[0007] US patent application US 2009 / 009263 A1 relates to a duplexer. The duplexer comprises an antenna terminal, a transmit filter, and a receive filter. The receive filter comprises a first subfilter containing one or more resonators and a second subfilter containing a dual-mode SAW (DMS) filter. The second subfilter is located downstream of the first subfilter relative to the antenna.

[0008] An object of the present disclosure is to provide an RF filter, an RF multiplexer, and an RF duplexer with good out-of-band attenuation and high linearity. Another object of the present disclosure is to provide this RF filter, this RF multiplexer, and this RF duplexer with a sufficiently small form factor. SUMMARY

[0009] According to the present disclosure, one or more of the above-mentioned objects are achieved by an RF filter according to the features of present claim 1.

[0010] One or more of the above-mentioned objects are also achieved by an RF duplexer according to the features of the present claim 4.

[0011] One or more of the above-mentioned objects are also achieved by an RF multiplexer according to the features of the present claim 6.

[0012] One or more of the above-mentioned objects are also achieved by an RF filter device according to the features of the present claim 8.

[0013] Advantageous embodiments are specified in the subclaims.

[0014] According to a first aspect of the present disclosure, an RF receive filter (RX filter) for receiving an RF signal from an antenna is presented. The RX filter includes an input port for receiving a radio-frequency signal from an antenna and an output port at which the filtered radio-frequency signal is provided. The RX filter includes a cascade connection of a bulk acoustic wave (BAW) filter section, a dual-mode SAW (DMS) filter, and a surface acoustic wave (SAW) filter section.

[0015] The BAW filter section comprises at least one BAW resonator and is arranged on an input side of the RX filter. The SAW filter section comprises at least one SAW resonator and is arranged on an output side of the RX filter. The DMS filter is arranged between the BAW filter section and the SAW filter section.

[0016] However, in real acoustic wave resonator devices, unwanted spurious modes can be excited in addition to desired acoustic modes. These unwanted spurious acoustic modes degrade the performance of the corresponding filter.

[0017] Furthermore, real acoustic wave resonators can exhibit nonlinear behavior, which can always generate harmonics whose frequencies are not necessarily an even multiple of the fundamental mode. These harmonics are sufficiently distant from the fundamental mode, but can interfere with other bands. In particular, in multiplexers and duplexers used in carrier aggregation applications, a single filter element with poor linear behavior can corrupt the third-order intermodulation effect of the entire multiplexer or duplexer.

[0018] SAW receive filters for multiplexing applications with high out-of-band attenuation can be realized with small dimensions, especially when using DMS filter structures. However, these filters have the disadvantage of having more spurious modes, which affect other bands during multiplexing, and poor odd-order linearity, particularly generating more third harmonics and third-order intermodulation products than BAW filters. BAW filters, on the other hand, offer high out-of-band reflection, are essentially free of spurious modes, and exhibit excellent odd-order linearity behavior. A major disadvantage of BAW filters is that there is no equivalent to the DMS filter structure, which provides high out-of-band attenuation over a wide frequency band, as required in many multiplexing applications, such as carrier aggregation.Therefore, a pure BAW solution for an RF receive filter has a much higher form factor and in most cases requires additional coils to generate electromagnetic poles, which also contributes to the space budget.

[0019] The RX filter according to the present disclosure enables the combination of the good electrical properties of both BAW and SAW technologies while still achieving a small form factor. The advantage of this combination and structure arises, for example, from the high suppression of the SAW strain gauge structures and the high linearity of the BAW filter sections.

[0020] According to embodiments of the first aspect, the BAW filter section has a ladder-like topology.

[0021] According to embodiments of the first aspect, acoustic structures of the BAW filter section and acoustic structures of the SAW filter section, as well as the acoustic structures of the DMS filter, are arranged on a single die. Preferably, when a single die is used, a thin-film SAW technology is used, and a silicon-based substrate is used for the BAW filter section, the SAW filter section, and the DMS filter. Alternatively, the die substrate comprises or consists of a piezoelectric material such as LiTaO3 or LiNbO3, wherein standard SAW resonators or temperature-compensated SAW resonators and BAW resonators are structured on the same die.

[0022] According to embodiments of the first aspect, the acoustic structures of the BAW filter section, the SAW filter section, and the DMS filter are arranged on the same surface of the die. This advantageously enables relatively simple manufacturing.

[0023] According to claim 1, the acoustic structures of the BAW filter section are arranged on a first surface of the die, and the acoustic structures of the SAW filter section and the DMS filter are arranged on a second surface opposite the first surface. This advantageously enables a potentially better use of the die area, resulting in a smaller component size.

[0024] According to embodiments of the first aspect, the acoustic structures of the BAW filter section are arranged on a first die, and the acoustic structures of the SAW filter section and the acoustic structures of the DMS filter are arranged on a second die, and the first and second dies are arranged in a stack. Accordingly, the various filter sections and the DMS filter can be arranged in a common assembly or on a common substrate, for example, a laminate. In particular, they can be arranged in a stack in a die-sized SAW assembly (DSSP stacked).

[0025] According to embodiments of the first aspect, the acoustic structures of the first die and the second die, respectively, are arranged on a first surface of the die, and the first die and the second die are arranged in the stack such that the first surfaces face each other. This has the advantage that the two acoustic layers can be encapsulated together, for example, by a surrounding copper or polymer frame between the two dies (see die-sized SAW assembly).

[0026] According to embodiments of the first aspect, the acoustic structures of the first die and the second die, respectively, are arranged on a first surface of the die, and the first die and the second die are arranged in the stack such that the first surfaces face the carrier. Electromagnetic coupling effects between the two electrode layers can have a negative impact on the filter effect. In this arrangement, the distance between the two layers is greater than in the previous arrangement. The coupling effects are correspondingly reduced.

[0027] According to a second aspect of the present disclosure, an RF duplexer is presented. A duplexer is an electronic device that enables bidirectional (duplex) communication over a single path. In radar and radio communication systems, this isolates the receiver from the transmitter while allowing them to share a common antenna. The duplexer comprises an RX filter according to the first aspect or an advantageous embodiment of the RX filter according to the first aspect.

[0028] The RF duplexer also includes an RF transmit filter (TX filter). The TX filter includes an output port and an input port, as well as a bulk acoustic wave (BAW) filter section with at least one BAW resonator. The output port of the TX filter and the input port of the RX filter are designed to be coupled or connected to a common antenna.

[0029] According to embodiments of the second aspect, the acoustic structures of the BAW filter section of the RX filter and the acoustic structures of the BAW filter section of the TX filter are arranged on a single die.

[0030] According to a third aspect of the present disclosure, an RF multiplexer is presented.

[0031] The RF multiplexer comprises a first RX filter according to the first aspect or an advantageous embodiment of the RX filter according to the first aspect.

[0032] Furthermore, the RF multiplexer comprises at least one further RX filter according to the first aspect or an advantageous embodiment of the RX filter according to the first aspect. The input port of the first RX filter and the input port of the at least one further RX filter are designed to be coupled or connected to a common antenna.

[0033] According to embodiments of the third aspect, the BAW filter section of the first RX filter and the BAW filter section of the at least one further RX filter are arranged on a first single die. Alternatively or additionally, the SAW filter section and the DMS filter of the first RX filter and the SAW filter section and the DMS filter of the at least one further RX filter are arranged on a second single die.

[0034] According to a fourth aspect of the present disclosure, an RF filter device is presented. The RF filter device comprises a first RF duplexer according to the third aspect or an advantageous embodiment of the RF duplexer according to the third aspect. In addition, the RF filter device comprises at least one further RF duplexer according to the third aspect or an advantageous embodiment of the RF duplexer according to the third aspect. The input ports of the RX filters and the output ports of the TX filters of the first duplexer and the at least one further RF duplexer are designed to be coupled or connected to a common antenna.

[0035] The RF filter device may comprise a combination of Tx, Rx, and TRx (TDD) filters, for example, a hexaplexer or octaplexer composed of three or four duplexers, or a pentaplexer composed of two duplexers and an additional Rx or TRx filter. Possible combinations of such pentaplexers include, for example, LTE band 1 Tx / Rx + LTE band 3 Tx / Rx + LTE band 7 Rx or LTE band 1 Tx / Rx + LTE band 3 Tx / Rx + LTE band 40 TRx.

[0036] According to embodiments of the fourth aspect, the BAW filter sections of the first RF duplexer and the BAW filter sections of the at least one further RF duplexer are arranged on a first single die and / or the SAW filter sections and the DMS filters of the first RF duplexer and the at least one further RF duplexer are arranged on a second single die. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] It is to be understood that both the foregoing general description and the following detailed description are given by way of example only and are intended to provide an overview or framework for understanding the nature and character of the claims. The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and, together with the description, serve to explain the principles and operation of various embodiments. The same elements in different figures of the drawings are designated by the same reference numerals.

[0038] The drawings are not necessarily drawn to scale, but are designed to clearly illustrate the disclosure.

[0039] They show: Fig. 1 is a block diagram of an exemplary embodiment of an RF receive filter, the Fig. 2a to 2c show various examples of encapsulation and integration of the RF reception filter, Fig. 3 is a block diagram of an exemplary embodiment of an RF duplexer, the Fig. 4a to 4c are block diagrams of exemplary embodiments of an RF multiplexer and the Fig. 5a to 5d are block diagrams of exemplary embodiments of another RF filter device. DETAILED DESCRIPTION OF EMBODIMENTS

[0040] Fig. Figure 1 shows a block diagram of an exemplary embodiment of an RF receive (RX) filter Rx. The RX filter Rx can be used, for example, in carrier aggregation applications.

[0041] The RX filter Rx comprises an input port A for receiving a high-frequency signal from an antenna Ant and an output port for providing the filtered high-frequency signal. Furthermore, the RX filter Rx comprises a cascade circuit consisting of a bulk acoustic wave (BAW) filter section, a surface acoustic wave (SAW) filter section with at least one SAW resonator, and a dual-mode SAW filter (DMS filter) DMS.

[0042] The BAW filter section is located on the input side of the RX filter Rx. The BAW filter section ensures highly linear filtering of the high-frequency signal. The SAW filter section SAW_f, located on the output side of the RX filter Rx, and the DMS filter DMS, located between the BAW filter section and the SAW filter section SAW_f, provide high out-of-band attenuation.

[0043] The BAW filter section BAW_f has, for example, a ladder-like topology. The BAW filter section BAW_f has, for example, a first and a second series BAW resonator and a first parallel BAW resonator. Alternatively, the topology of the BAW filter section BAW_f can be simpler or more complex.

[0044] In a BAW resonator, a piezoelectric material is sandwiched in a piezoelectric layer between a lower electrode in a lower electrode layer and an upper electrode in an upper electrode layer. The piezoelectric material, in combination with the electrodes, converts between acoustic and electromagnetic RF signals through the piezoelectric effect. The lower electrode, the upper electrode, and the piezoelectric layer sandwiched between the electrodes form an acoustic structure.

[0045] Such an acoustic structure is arranged on a carrier, in particular a die or a chip.

[0046] The SAW filter section comprises, for example, a third series SAW resonator S3 and a second parallel SAW resonator P2. Alternatively, the topology of the SAW filter section SAW_f can be simpler or more complex.

[0047] A SAW resonator has two transducers (interdigital transducers, or IDTs) consisting of a pair of comb-shaped electrodes (also known as fingers) mounted on a die. The substrate of the die comprises silicon or a piezoelectric material. Specifically, the substrate can be made of silicon or the piezoelectric material. The electrical material is, for example, LiTaO3 or LiNbO3.

[0048] A DMS filter DMS is a special type of surface acoustic wave filter.

[0049] The DMS filter (DMS) comprises longitudinally coupled input and output transducers arranged in an acoustic path. The DMS filter (DMS) comprises one or more input IDTs and one or more output IDTs (IDTs = interdigital transducers). The IDTs are arranged between electroacoustic reflectors.

[0050] The Fig. 2a to 2c show different examples of the encapsulation and integration of the RX filter Rx.

[0051] Fig. 2a shows an encapsulation configuration, wherein the acoustic structures AS of the BAW filter section BAW_f are arranged on a first die, and the acoustic structures AS of the SAW filter section SAW_f and the DMS filter DMS are arranged on a second die. For example, the first die is arranged in a first assembly, and the second die is arranged in a second assembly. Alternatively, the first and second die are arranged in a common carrier substrate.

[0052] In the following, a die that comprises acoustic structures AS only of BAW resonators is referred to as BAW die BAW_die and a die that comprises acoustic structures AS only of a SAW resonator that also has acoustic structures AS of a DMS filter DMS is referred to as SAW die SAW_die.

[0053] Fig. 2b shows encapsulation configurations wherein the acoustic structures AS of the BAW filter section BAW_f are arranged on a BAW die and the acoustic structures AS of the SAW filter section SAW_f and the acoustic structures AS of the DMS filter DMS are arranged on a SAW die SAW_die and the BAW die BAW_die and the SAW die SAW_die are arranged on a carrier substrate and / or in a single assembly in a stack.

[0054] According to Fig. 2b, the acoustic structures AS of the BAW die BAW_die and the SAW die SAW_die are arranged, for example, on a first surface of the respective die. As shown in Fig. 2b (1), the BAW die BAW_die and the SAW die SAW_die can be arranged in the stack such that the first surfaces face each other.

[0055] Alternatively, as in Fig. 2b (2), the BAW die BAW_die and the SAW die SAW_die are arranged in the stack such that the first surfaces are directed in the same direction, wherein in particular the first surfaces are directed towards the carrier.

[0056] Fig. Figure 2c shows encapsulation configurations where the acoustic structures AS of the BAW filter section BAW_f and the acoustic structures AS of the SAW filter section SAW_f and the acoustic structures AS of the DMS filter DMS are arranged on a single die.

[0057] As in Fig. As shown in Figure 2c (1), the acoustic structures AS of the BAW filter section BAW_f and the SAW filter section SAW_f and the DMS filter DMS can be arranged on the same surface of the die.

[0058] Alternatively, as in Fig. 2c (2), the acoustic structures AS of the BAW filter section BAW_f are arranged on the first surface of the die and the acoustic structures AS of the SAW filter section SAW_f and of the DMS filter DMS can be arranged on the surface opposite the first surface.

[0059] Fig. Figure 3 shows a block diagram of an exemplary embodiment of an RF duplexer. Fig. 3 and the following figures, the resonators of the BAW filter section BAW_f and the SAW filter section SAW_f of the RX filter Rx are no longer shown in detail, but generalized filter topologies of resonator networks RN are shown.

[0060] The RF duplexer is a high-frequency filter that enables simultaneous transmission in a first frequency band and reception in a second frequency band (different from the first frequency band) using a common antenna Ant.

[0061] The RF duplexer includes an RX filter Rx as described above and in the Fig. 1 to 3. Furthermore, the RF duplexer comprises an RF transmit filter (TX filter) Tx. The TX filter Tx comprises an output port and an input port, as well as a further bulk acoustic wave (BAW) filter section BAW_f with at least one BAW resonator. The output port of the TX filter Tx and the input port A of the RX filter Rx are configured to be coupled to a common antenna Ant. The RX filter Rx and the TX filter Tx have different passbands.

[0062] According to an optional embodiment, the acoustic structures AS of the BAW filter section BAW_f of the RX filter Rx and the acoustic structures AS of the BAW filter section BAW_f of the TX filter Tx are arranged on a single BAW die BAW_die. Alternatively, the acoustic structures AS of the BAW filter section BAW_f of the TX filter Tx and the acoustic structures AS of the BAW filter section BAW_f of the RX filter Rx can be arranged on different BAW dies BAW_die.

[0063] Furthermore, according to further optional embodiments, the RF duplexer uses the same encapsulation configurations as those described in the Fig. 2a to 2c.

[0064] The Fig. 4a to 4c show block diagrams of exemplary embodiments of an RF multiplexer.

[0065] An RF multiplexer is a high-frequency filter with more than two ports and multiple passbands.

[0066] In the Fig. 4a to 4c show respective diplexers. The diplexers comprise at least three ports, namely a common input port for connection to the antenna Ant and at least two output ports. The diplexers comprise at least two RX filters, for example, a first RX filter Rx_1 and another RX filter Rx_2, as described above and in the Fig. 1 to 3. The first and the further RX filters Rx_1, Rx_2 have different passbands.

[0067] For example, the acoustic structures AS of the BAW filter section BAW_fs and the SAW filter sections SAW_f of the first and the further RX filter Rx_1, Rx_2 are each arranged on a separate die. Preferably, the acoustic structures AS of the SAW filter sections and the acoustic structures AS of the DMS filter DMS of the first RX filter Rx_1 are arranged on a common SAW die SAW_die and / or the acoustic structures AS of the SAW filter sections SAW_f and the acoustic structures AS of the DMS filter DMS of the further RX filter Rx_2 are arranged on another common SAW die SAW_die (see Fig. 4a).

[0068] According to an optional embodiment, the acoustic structures AS of the BAW filter sections BAW_f of the first RX filter Rx_1 and the further RX filter Rx_2 can be arranged on a single BAW die BAW_die (see Fig. 4b).

[0069] Alternatively or additionally, the acoustic structures AS of the SAW filter section SAW_f and the acoustic structures AS of the DMS filter DMS of the first RX filter Rx_1 and the acoustic structures AS of the SAW filter section SAW_f and the acoustic structures AS of the DMS filter DMS of the further RX filter Rx_2 are arranged on a second single SAW die SAW_die (see Fig. 4c).

[0070] Furthermore, according to further optional embodiments, the RF multiplexer may use the same encapsulation configurations as described in the Fig. 2a to 2c are shown.

[0071] The Fig. 5a to 5d show block diagrams of exemplary embodiments of another RF filter device. The RF filter device comprises a first RF duplexer and at least one further RF duplexer, as described above and in Fig. 3. The exemplary embodiments from the Fig. Figures 5a to 5d show the RF filter device with a first RF duplexer and a further RF duplexer. The input ports of the RX filters Rx_1, Rx_2 and the output ports of the TX filters Tx_1, Tx_2 of the first RF duplexer and the further RF duplexer are coupled to a common antenna Ant.

[0072] The acoustic structures AS of the BAW filter sections BAW_f and the SAW filter sections SAW_f as well as the DMS filter DMS can be arranged on at least two different dies, as shown in the Fig. 5a to 5d. In particular, two or more BAW filter sections BAW_f can be combined. The same applies to the SAW filter sections SAW_f and the DMS filters DMS of the RX filters Rx_1, Rx_2.

[0073] The substrate of the respective BAW die and / or SAW die and / or the combined die comprises or consists of silicon or a piezoelectric material, for example. The piezoelectric material is, for example, LiTaO3 or LiNbO3. REFERENCE SYMBOL A Input port of the RX filter Ant antenna AS acoustic structures BAW_f BAW filter section DMS DMS filter P1, P2 parallel resonator R Output port of the RX filter RN resonator network Rx, Rx_1, Rx_2 RX filters S1, S2, S3 series resonator SAW_f SAW filter section T Input port of the TX filter Tx, Tx_1, Tx_2 TX filter

Claims

[1] RF reception filter (RX filter) (Rx), which comprises an input port (A) for receiving a radio frequency signal from an antenna and an output port (R) for providing the filtered radio frequency signal, and a cascade circuit of a bulk acoustic wave (BAW) filter section (BAW_f), a surface acoustic wave (SAW) filter section (SAW_f) with at least one SAW resonator and a dual-mode SAW filter (DMS filter) (DMS), wherein - the BAW filter section (BAW_f) comprises at least one BAW resonator and is arranged on an input side of the RX filter (Rx), - the SAW filter section (SAW_f) comprises at least one SAW resonator and is arranged on an output side of the RX filter (Rx), and - the DMS filter (DMS) is arranged between the BAW filter section (BAW_f) and the SAW filter section (SAW_f), wherein acoustic structures (AS) of the BAW filter section (BAW_f) and acoustic structures (AS) of the SAW filter section (SAW_f) and acoustic structures (AS) of the DMS filter (DMS) are arranged on a single die, wherein the acoustic structures (AS) of the BAW filter section (BAW_f) are arranged on a first surface of the die and the acoustic structures (AS) of the SAW filter section (SAW_f) and the DMS filter (DMS) are arranged on a surface opposite the first surface. [2] RX filter (Rx) according to claim 1, wherein the BAW filter section (BAW_f) has a ladder-like topology. [3] RX filter (Rx) according to claim 2, wherein the BAW filter section (BAW_f) comprises a first and a second series BAW resonator (S1, S2) and a first parallel BAW resonator (P1). [4] RF duplexer, which includes: - an RX filter (Rx) according to one of claims 1 to 3, - an RF transmit filter (TX filter) (Tx) comprising an output port (T) and an input port and a bulk acoustic wave (BAW) filter section (BAW_f) with at least one BAW resonator, wherein the output port of the TX filter (Tx) and the input port (A) of the RX filter (Rx) are designed to be coupled to a common antenna (Ant). [5] RF duplexer according to claim 4, wherein the acoustic structures (AS) of the BAW filter section (BAW_f) of the RX filter (Rx) and the acoustic structures (AS) of the BAW filter section (BAW_f) of the TX filter (Tx) are arranged on a single die. [6] RF multiplexer, which includes: - a first RX filter (Rx_1) according to one of claims 1 to 3, - at least one further RX filter (Rx_2) according to one of claims 1 to 3, wherein the input port of the first RX filter (Rx_1) and the input port of the at least one further RX filter (Rx_2) are designed to be coupled to a common antenna (Ant). [7] RF multiplexer according to claim 6, wherein the acoustic structures (AS) of the BAW filter section (BAW_f) of the first RX filter (Rx_1) and the acoustic structures (AS) of the BAW filter section (BAW_f) of the at least one further RX filter (Rx_2) are arranged on a first single die and / or wherein the acoustic structures (AS) of the SAW filter section (SAW_f) and the acoustic structures (AS) of the DMS filter (DMS) of the first RX filter (Rx_1) and the acoustic structures (AS) of the SAW filter section (SAW_f) and the acoustic structures (AS) of the DMS filter (DMS) of the at least one further RX filter (Rx_2) are arranged on a second single die. [8] RF filter device comprising: - a first RF duplexer according to claim 4 or 5, - at least one further RF duplexer according to claim 4 or 5, wherein the input ports of the RX filters (Rx_1, Rx_2) and the output ports of the TX filters (Tx_1, Tx_2) of the first RF duplexer and the at least one further RF duplexer are designed to be coupled to a common antenna. [9] RF filter device according to claim 8, wherein the BAW filter sections (BAW_f) of the first RF duplexer and the BAW filter sections (BAW_f) of the at least one further RF duplexer are arranged on a first single die and / or wherein the SAW filter sections (SAW_f) and the DMS filters (DMS) of the first RF duplexer and the at least one further RF duplexer are arranged on a second single die.

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