Radio frequency filter, high selectivity triplexer and communication device

Abstract

Communication device (300), comprising: a triplexer (320, 400, 1100) with a common port and first, second and third branching ports; the triplexer includes (320, 400, 1100): a hybrid inductor-capacitor / surface acoustic wave (LC / SAW) high-pass filter (410, 600, 700) coupled between the common port (Com.) and the third branching port (B3); a hybrid (LC / SAW) low-pass filter (420, 800, 900, 1000) coupled between the common port (Com.) and an internal node; an LC high-pass filter (430, 1130) coupled between the internal node and the second branching port (B2); an LC low-pass filter (440, 1140) coupled between the internal node and the first branching port (B1).

Description

BACKGROUND area

[0001] This disclosure relates to radio frequency filters that use surface acoustic wave (SAW) resonators, and specifically filters and duplexers for use in communication equipment. Description of the state of the art

[0002] A radio frequency (RF) filter is a two-terminal device configured to pass some frequencies and block others, where "pass" means forwarding with relatively low insertion loss, and "block" means blocking or significantly attenuating the signal. The range of frequencies passed through a filter is called the filter's "passband." The range of frequencies blocked by such a filter is called the filter's "stopband." A typical RF filter has at least one passband and at least one stopband. Specific requirements for a passband or stopband depend on the particular application. For example, a "passband" might be defined as a frequency range where the filter's insertion loss is less than a defined value, such as 1 dB, 2 dB, or 3 dB.A "stopband" can be defined as a frequency range where the insertion loss of a filter is greater than a defined value, such as twenty dB, twenty-five dB, forty dB or more, depending on the application.

[0003] RF filters are used in communication systems where information is transmitted over wireless links. For example, RF filters can be found in the RF front ends of base stations, mobile phones and computing devices, satellite transmitters / receivers and ground stations, IoT (Internet of Things) devices, laptops and tablets, fixed-point radio links, and other communication systems. RF filters are also used in radar and electronic warfare systems.

[0004] RF filters typically require numerous design compromises to achieve the best balance between performance parameters such as insertion loss, suppression, isolation, power handling, linearity, size, and cost for each specific application. Special design and manufacturing processes and improvements can simultaneously favor one or more of these requirements.

[0005] Improvements in RF filter performance within a wireless system can have a broad impact on overall system performance. RF filter enhancements can be effectively implemented to deliver system performance improvements such as larger cell size, extended battery life, higher data rates, greater network capacity, reduced costs, enhanced security, and increased reliability. These improvements can be achieved at many levels of the wireless system, both individually and in combination, including RF module, RF transmitter / receiver, mobile or fixed subsystem, and network levels.

[0006] Surface acoustic wave (SAW) resonators are used in numerous RF filters, including bandstop filters, bandpass filters, duplexers, and multiplexers. A duplexer is a radio frequency filter device that allows simultaneous transmission in a first frequency band and reception in a second frequency band (different from the first) using a common antenna. A multiplexer is a radio frequency filter with more than two input and output ports and multiple passbands. A triplexer is a multiplexer with four ports and three passbands.

[0007] How Fig. As shown in Figure 1, a typical SAW resonator 100 is formed by thin-film conductor patterns formed on the surface of a substrate 105, which consists of a piezoelectric material such as quart, lithium niobate, lithium tantalate, or lanthanum gallium silicate. The substrate 105 is generally a single-crystal wafer of the piezoelectric material or a composite substrate containing a thin single-crystal wafer of the piezoelectric material bonded to another material such as silicon, sapphire, or quartz. A composite substrate is generally used to provide a coefficient of thermal expansion that differs from that of the single-crystal piezoelectric material alone. A first interdigital converter (IDT) 110 contains a plurality of parallel conductors.A radio frequency or microwave signal applied to the first IDT 110 via an input terminal IN generates an acoustic wave on the surface of the substrate 105. As in . Fig. As shown in Figure 1, the surface acoustic wave propagates to the left. A second IDT 120 converts the acoustic wave back into a radio frequency or microwave signal at the output terminal OUT. The conductors of the second IDT 120 are interwoven with the conductors of the first IDT 110 as shown. In other typical SAW resonator configurations (not shown), the conductors forming the second IDT are arranged on the surface of the substrate 105 adjacent to or separate from the conductors forming the first IDT. Likewise, additional fingers (generally referred to as "dummy" fingers) are sometimes formed opposite the ends of the IDT fingers and connected to the IN and OUT busbars of the first and second IDTs 110 and 120, respectively. Grating reflectors 130, 135 are arranged on the substrate to limit a large part of the energy of the acoustic waves to the area of ​​the substrate occupied by the first and second IDT 110, 120.The grid reflectors 130 and 135 float or are connected to either the IN or OUT terminal. Generally, the SAW resonator 100 is bidirectional, and the IN and OUT terminal designations can be reversed.

[0008] The electro-acoustic coupling between the first IDT 110 and the second IDT 120 is strongly frequency-dependent. The fundamental behavior of acoustic resonators (SAW, acoustic volume wave, acoustic film volume wave, etc.) is generally described using the Butterworth Van Dyke (BVD) circuit model, as shown in Fig. Figure 2A shows the BVD circuit model, which consists of a moving arm and a static arm. The moving arm contains a motion inductor L. m , a movement capacity C m and a resistor R mThe static arm contains a static capacitance C0 and a resistance R0. While the BVD model does not fully describe the behavior of an acoustic resonator, it does a good job of representing the two primary resonances as a model used to design bandpass filters, duplexers, and multiplexers (multiplexers are filters with more than two input or output ports with multiple passbands).

[0009] The first primary resonance of the BVD model is the motion resonance, which is determined by the series combination of the motion inductance L. m and the movement capacity C m is caused. The second primary resonance of the BVD model is the antiresonance, which is caused by the combination of the motion inductance L. m , the movement capacity C m and is caused by the static capacitance C0. In a lossless resonator (R m (R0 = 0) is the frequency F rthe movement resonance given by Fr=12πLmCm

[0010] The frequency F a The antiresonance is given by Fa=Fr1+1y where γ = C0 / C m a property of the substrate on which the SAW resonator is manufactured, γ depends on both the material and the orientation of the crystalline axes of the substrate as well as the physical design of the IDTs.

[0011] The frequencies of the motion resonance and the antiresonance are primarily determined by the division and orientation of the interlocking conductors, the choice of substrate material, and the crystallographic orientation of the substrate material.

[0012] Fig. Figure 2B is a curve of the admittance of a theoretical lossless acoustic resonator. The admittance exhibits a motion resonance 212, where the admittance of the resonator approaches infinity, and an antiresonance 214, where the admittance of the resonator approaches zero. In highly simplified terms, the lossless acoustic resonator can be considered a short circuit at the frequency of the motion resonance 212 and an open circuit at the frequency of the antiresonance 214. The frequencies of the motion resonance 212 and the antiresonance 214 are representative, and a resonator can be designed for other frequencies.

[0013] Cellular phones operate in different frequency bands, which are defined by industry or government standards. For example, the 3GPP LTE (Third Generation Partnership Project Long Term Evolution) standard defines 48 different bands over a frequency range of approximately 450 MHz to more than 5000 MHz. Each of these bands consists of a frequency range or a pair of unconnected frequency ranges used for cellular phone communication. For example, Band 12, used in the United States and Canada, uses the frequency range of 699 MHz to 716 MHz for communication from the cellular device to the cellular network and the frequency range of 729 MHz to 746 MHz for communication from the network to the device. Band 40, used in several Asian countries, uses the frequency range of 2300 MHz to 2400 MHz for two-way communication.All bands defined by the 3GPP LTE standard are currently not in use, and typically only one or a few bands are used in a given country. Furthermore, different providers of a cellular service in a given country may each have frequency allocations within one or more bands.

[0014] Carrier aggregation is a technique for increasing data rates by sending multiple signals, or carriers, to a cellular phone. These multiple signals can be within the same band or across multiple bands if the service provider has frequency allocations in several bands.

[0015] From US patent 7,190,970 B2, a multiplexer is known in which SAW filters and LC filters are used to implement a low-pass filter, a band-pass filter, and a high-pass filter, with one terminal of each filter connected to a common port. From US patent 2007 0190954 A1, a high-frequency circuit is known that uses SAW filters and LC filters. Furthermore, US patent 2014 0035702 A1 discloses hybrid filters with SAW stages and LC stages.

[0016] To enable international roaming, it is desirable for cellular phones to be able to operate in as many frequency bands as possible. Furthermore, to facilitate carrier aggregation, it is desirable for cellular phones to be capable of simultaneous operation in multiple frequency bands.

[0017] The present invention provides a communication device according to claim 1, hybrid LC / SAW filters according to claims 7 and 8, a hybrid LC / SAW high-pass filter according to claim 11 and a hybrid LC / SAW low-pass filter according to claim 14. Further developments of the invention are set out in the dependent claims. DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a simplified schematic top view of a SAW resonator. Fig. 2A is an equivalent circuit of a SAW resonator. Fig. Figure 2B is a graph of the admittance of a lossless SAW resonator. Fig. Figure 3 is a block diagram of a communication device that includes a triplexer. Fig. 4 is a block diagram of an exemplary triplexer for use in the communication device of Fig. 3. Fig. Figure 5 is a block diagram of a hybrid LC / SAW filter. Fig. Figure 6A is a schematic representation of an exemplary hybrid LC / SAW high-pass filter. Fig. Figure 6B is a graph showing S (2, 1) of the exemplary hybrid LC / SAW high-pass filter of Fig. 6A is shown. Fig. Figure 7A is a schematic representation of another exemplary hybrid LC / SAW high-pass filter. Fig. 7B is a graph showing S (2,1) of the exemplary hybrid LC / SAW high-pass filter of Fig. 7A is shown. Fig. Figure 8A is a schematic representation of an exemplary hybrid LC / SAW low-pass filter. Fig. Figure 8B is a graph showing S (2, 1) of the exemplary hybrid LC / SAW low-pass filter of Fig. 8A is shown. Fig. Figure 9A is a schematic representation of an exemplary hybrid LC / SAW bandpass filter. Fig. Figure 9B is a graph showing S (2, 1) of the exemplary hybrid LC / SAW bandpass filter of Fig. 9A is shown. Fig. Figure 10A is a schematic representation of an exemplary hybrid LC / SAW bandstop filter. Fig. Figure 10B is a graph showing S(2,1) of the exemplary hybrid LC / SAW bandstop filter of Fig. 10A is displayed. Fig. 11 is a schematic representation of a triplexer, intended for use in the communication device of Fig. 3 is suitable. Fig. 12 is a graph showing S(2,1), S(3,1) and S(4,1) of the triplexer of Fig. 11 shows.

[0018] In this description, elements appearing in the figures are consistently assigned three-digit reference symbols, where the most significant digit is the number of the figure in which the element is first depicted, and the two least significant digits are specific to the element. An element not described in connection with a figure can be assumed to have the same properties and function as a previously described element with the same reference symbol. DETAILED DESCRIPTION Description of the apparatus

[0019] Fig. Figure 3 is a block diagram of a multi-band communication device 300. The communication device 300 includes an antenna 310, a high-selectivity triplexer 320, and three transceivers. The triplexer 320 has a common port (Com.) and three branch ports (B1, B2, B3). The common port is connected to the antenna 310. The first branch port, B1, is connected to a low-band transceiver 330, which is configured to operate in frequency bands (i.e., bands 5, 8, 12, 13, 17, 20, 28, 31, etc.) between 450 MHz and 960 MHz. The second branch port B2 is coupled to a medium-band transceiver 340 configured to operate in frequency bands (i.e., bands 1, 2, 3, 4, 25, 66, etc.) between 1400 MHz or 1500 MHz and 2200 MHz. The third branch port B3 is coupled to a high-band transceiver 350 configured to operate in frequency bands (i.e., bands 7, 30, 38, 40, 41, 42, 43, etc.) between 2300 MHz and 3500 MHz or higher.The division of the frequency spectrum into "low bands", "middle bands" and "high bands" is partly determined by the fact that the frequency ranges from 960 MHz to 1420 MHz and 2200 MHz to 2300 MHz are not used by any defined cellular communication band.

[0020] The Triplexer 320 functions like three filters: a low-band filter 322, configured between the common port and the first branch port; a mid-band filter 324, configured between the common port and the second branch port; and a high-band filter 326, formed between the common port and the third branch port. The low-band filter 322 has a passband of 450 MHz to 960 MHz and stopbands of 1400 MHz to 2200 MHz and 2300 MHz to more than 3500 MHz. The mid-band filter 324 has a passband of 1400 MHz to 2200 MHz and stopbands of 450 MHz to 960 MHz and 2300 MHz to more than 3500 MHz. The high-band filter 326 has a passband from 2300 MHz to more than 3500 MHz and stopbands from 450 MHz to 960 MHz and 1400 MHz to 2200 MHz.While the function of the Triplexer 320 can be described as a three-bandpass filter, the internal structure of the Triplexer can be a combination of bandpass, lowpass, highpass and bandstop filters.

[0021] The Triplexer 320 can be described as having “high selectivity” because the transition region between the high-band frequency range and the mid-band frequency range is only 100 MHz or less than 5% of the frequency at the edges of these bands.

[0022] Each of the Low Band Radio 330, Medium Band Radio 340 and High Band Radio 350 contains one or more transmitters and one or more receivers and may contain one or more filters, duplexers, switches, processors and other components, enabling the radio to communicate over one band or multiple bands within the respective frequency range.

[0023] Fig. Figure 4 is a block diagram of a highly selective triplexer 400, which is intended for use as the triplexer 320 in the communication device 300 of Fig. 3 is suitable. A common port is connected to a first high-pass filter 410 and a first low-pass filter 420. The first high-pass filter 410 is configured to allow frequencies above 2300 MHz to pass with low insertion loss and to block or significantly attenuate frequencies below 2200 MHz. Typical specifications for the first high-pass filter 410 may include an insertion loss of less than 3 dB at frequencies between 2300 MHz and at least 3500 MHz, and an insertion loss of more than 25 dB for frequencies below 2200 MHz. In contrast, the first low-pass filter 420 is configured to allow frequencies below 2200 MHz to pass with low insertion loss and to block frequencies above 2300 MHz. Typical specifications for the first low-pass filter 420 may include an insertion loss of less than 3 dB at frequencies below 2200 MHz and an insertion loss of more than 25 dB for frequencies above 2300 MHz.

[0024] The output of the low-pass filter 420 is further divided into mid- and low-frequency ranges by a second high-pass filter 430 and a second low-pass filter 440. The second high-pass filter 430 is configured to allow frequencies between 1400 MHz and at least 2200 MHz to pass with low insertion loss and to suppress or significantly attenuate frequencies below 960 MHz. The second low-pass filter 440 is configured to allow frequencies between 450 MHz and 960 MHz to pass with low insertion loss and to suppress or significantly attenuate frequencies between 1400 MHz and 2200 MHz.

[0025] Acoustic resonators, such as the SAW resonator described earlier, are capable of providing a highly resonant Q (quality factor) in a small component volume. Such resonators are generally used in bandpass filters with high selectivity and narrow bandwidth, and in duplexers for use in communication devices. However, the inherent coupling between the resonance and antiresonance of acoustic resonators limits the achievable bandwidth. In contrast, passive reactive components such as capacitors, inductors, phase shifters, and other passive elements can be used to implement filters with arbitrary bandwidth but low selectivity due to the limited Q of such components. Such filters are referred to here as LC filters (L and C being the usual designations for inductors and capacitors, respectively, in electronic schematics).

[0026] Fig. Figure 5 is a conceptual diagram of a hybrid LC / SAW filter 500, which includes a low-Q LC filter 510 and at least one high-Q SAW resonator. In this context, the terms "low-Q" and "high-Q" are relative, indicating that the Q of the SAW resonator is essentially higher than the Q of the LC filter. The Q of the LC filter 510 is typically determined by the Q of the inductors within the filter, which might be around 100, for example. The Q of the SAW resonator 520 / 530 / 540 might be greater than 1000, for example.

[0027] The SAW resonator can be a parallel resonator 520 connected in parallel to all or part of the LC filter 510. The SAW resonator can be a series resonator 530 connected in series with the LC filter 510. The SAW resonator can be a shunt resonator 540 connected between ground and one of Port 1, Port 2, or an internal node within the LC filter 510. In some hybrid LC / SAW filters, more than one parallel resonator 520, series resonator 530, and shunt resonator 540 may be present. In some hybrid LC / SAW filters, two or more parallel resonators, series resonators, or shunt resonators may be present.

[0028] The LC filter 510 has at least one passband and at least one stopband, which define the function (high-pass, low-pass, band-pass, etc.) of the hybrid LC / SAW filter 500. Frequency-adjacent passbands and stopbands are separated by a crossover frequency region. The LC filter 510 and other LC filters to be discussed subsequently can be implemented using single, printed, or distributed capacitors and inductors, and combinations thereof. Printed and distributed components can be formed using thin-film conductors and insulators, co-fired low-temperature ceramic (LTCC) conductors and insulators, or other component fabrication technologies.

[0029] The SAW resonator 520 / 530 / 540 is configured to improve the selectivity of the entire hybrid LC / SAW filter 500 by sharpening a transition between a passband and a stopband of the LC filter 510. As shown in Fig. As shown in Figure 2B, a SAW resonator has a very high admittance at its resonant frequency and a very low admittance at its antiresonant frequency. In simplified terms, a SAW resonator can be considered a short circuit at the resonant frequency and an open circuit at the antiresonant frequency.

[0030] A parallel SAW resonator 520 can improve the selectivity of the LC filter 510 if the resonant frequency of the SAW resonator lies within a transition region of the LC filter. In this case, the energy at the resonant frequency, which would only be partially transmitted through the LC filter in the absence of the SAW resonator, bypasses the LC filter via the SAW resonator.

[0031] A SAW series resonator 530 can improve the selectivity of the LC filter 510 if the antiresonance frequency of the SAW resonator lies within a transition region of the LC filter. In this case, the energy at the resonance frequency, which would be partially transmitted through the LC filter in the absence of the SAW resonator, is blocked by the SAW resonator.

[0032] A SAW shunt resonator 540 can improve the selectivity of the LC filter 510 if the resonant frequency of the SAW resonator lies within a transition region of the LC filter. In this case, energy at the resonant frequency, which would be partially passed through the LC filter in the absence of the SAW resonator, is short-circuited to ground by the SAW resonator. Example 1

[0033] Fig. Figure 6A is a schematic representation of a hybrid LC / SAW high-pass filter 600. The hybrid LC / SAW high-pass filter 600 contains an LC high-pass filter implemented using four capacitors C1-C4 and three inductors L1-L3, and a parallel SAW resonator XI. The four capacitors C1-C4 can be described as "series" elements because they are connected in series between the two ports of the filter 600. The three inductors L1-L3 can be described as "shunt" elements because they are coupled between the series elements and ground and serve to shunt certain signals to ground. A high-pass LC filter generally contains series capacitors and shunt inductors. In contrast, a low-pass LC filter generally contains series inductors and shunt capacitors.

[0034] Fig. Figure 6B is a graph of S(2,1) of the hybrid LC / SAW high-pass filter 600, as simulated by the circuit of Fig. 6A derived. S-parameters are a convention used to describe the performance of linear electrical networks. The full line 660 is a curve of S(2,1), which is the voltage transfer function from port 1 to port 2 of an electrical network. S(2,1) is often given in dB, that is, 20log 10 [S(2,1)], and is essentially the energy gain of the device. Passive devices such as filters, however, are usually characterized by the "insertion loss" of the filter, which is numerically the same as the energy gain but with a change in sign (e.g., S(2,1) = -3 dB is equivalent to an insertion loss of 3 dB). In this case, the solid line 660 represents the input-to-output function of the filter 600. The hybrid LC / SAW high-pass filter 600 provides less than 3 dB loss at frequencies above 2300 MHz and more than 25 dB attenuation at frequencies below 2190 MHz. Example 2

[0035] Fig. Figure 7A is a schematic representation of another hybrid LC / SAW high-pass filter 700. The hybrid LC / SAW high-pass filter 700 includes an LC high-pass filter implemented using two series capacitors C1-C2 and two shunt inductors L1-L2, and a parallel SAW resonator XI and a SAW shunt resonator X2.

[0036] Fig. Figure 7B is a graph of S(2,1) of the hybrid LC / SAW high-pass filter 700, as simulated by the circuit of Fig. 7A derived. The full line 760 is a representation of the input-output transfer function of the hybrid LC / SAW high-pass filter 700. The hybrid LC / SAW high-pass filter 700 provides less than 2 dB loss at frequencies above 2300 MHz and more than 25 dB attenuation at frequencies below 2210 MHz. Example 3

[0037] Hybrid LC / SAW filters are not limited to high-pass filters. Fig. Figure 8A is a schematic representation of a hybrid LC / SAW low-pass filter 800. Inductor L3 and capacitor C3 form an LC low-pass filter section in series with a "bridged-T" circuit consisting of capacitor C4, inductors L4 and L5, and SAW resonator X3. Inductors L4 and L5 and the SAW shunt resonator X3 form the "T," and capacitor C4 is the "bridge." The SAW resonator X3 replaces a capacitor that would otherwise be used in a conventional bridged-T circuit. The SAW resonator X3 effectively improves the selectivity of the LC low-pass filter by shunting signals within the LC low-pass filter's crossover frequency range to ground.

[0038] Fig. Figure 8B is a graph of S(2,1) of the hybrid LC / SAW low-pass filter 800 as simulated by the circuit of Fig. 8A derived. The full line 860 is a representation of the input-output transfer function of the hybrid LC / SAW low-pass filter 800. The hybrid LC / SAW high-pass filter 800 provides less than 2 dB loss at frequencies below 2200 MHz and more than 25 dB attenuation at frequencies above 2330 MHz. Example 4

[0039] Fig. Figure 9A is a schematic representation of a hybrid LC / SAW bandpass filter 900. A series SAW resonator X1 is connected in series with two LC bandpass filter sections. The series SAW resonator X1 effectively improves the selectivity of the LC bandpass filter by blocking signals at the resonator's antiresonance frequency (approximately 1785 MHz), which lies within the crossover frequency range at the upper end of the LC filter's passband.

[0040] Fig. Figure 9B is a graph of S(2,1) of the hybrid LC / SAW bandpass filter 900, as simulated by the circuit of Fig. 9A derived. The full line 960 is a representation of the input-output transfer function of the hybrid LC / SAW low-pass filter 900. Example 5

[0041] Fig. Figure 10A is a schematic representation of a hybrid LC / SAW bandstop filter 1000, which includes two SAW resonators X1 and X2 connected in parallel with parts of an LC bandstop filter. The LC bandstop filter contains phase-shift elements P1, P2, P3, P4, which can be implemented, for example, by the lengths of transmission lines.

[0042] Fig. Figure 10B is a graph of the S(2,1) of the hybrid LC / SAW bandstop filter 1000, as simulated by the circuit of Fig. 10A derived. The full line 1060 is a representation of the input-output transfer function of the hybrid LC / SAW low-pass filter 1000. Example 6

[0043] Fig. Figure 11 is a schematic representation of a highly selective triplexer 1100, which is intended for use as the triplexer 320 in the communication device 300 of Fig. 3 is suitable. A first port (antenna port) is connected to a 700 high-pass filter and an 800 low-pass filter, as previously described in Fig. 7A or Fig. Figure 8A shows the following. The high-pass filter 700 is configured to allow frequencies above 2300 MHz to pass with low insertion loss and to block or significantly attenuate frequencies below 2200 MHz. The low-pass filter 800 is configured to allow frequencies below 2200 MHz to pass with low insertion loss and to block or significantly attenuate frequencies above 2300 MHz.

[0044] The output of the 800 low-pass filter is further subdivided into mid- and low-frequency ranges by a second high-pass filter 1030 and a second low-pass filter 1040. The second high-pass filter 1030 is an LC filter configured to allow frequencies between 1200 MHz and at least 2200 MHz to pass with low insertion loss and to block or significantly attenuate frequencies below 960 MHz. The second low-pass filter 1040 is an LC filter configured to allow frequencies between 450 MHz and 960 MHz to pass with low insertion loss and to suppress or significantly attenuate frequencies above 1500 MHz.

[0045] Fig. Figure 12 is a graph of S(2,1), S(3,1) and S(4,1) of the highly selective triplexer 1100, as simulated by the circuit of Fig.11. The solid line 1210 is a representation of the input-output transfer function from the antenna port (Port 1) to the high-band transceiver port (Port 2) of the Triplexer 1100. The dashed line 1220 is a representation of the input-output transfer function from the antenna port (Port 1) to the medium-band transceiver port (Port 3) of the Triplexer 1100. The dotted-dash line 1230 is a representation of the input-output transfer function from the antenna port (Port 1) to the low-band transceiver port (Port 4) of the Triplexer 1100. Concluding remarks

[0046] Throughout this description, the embodiments and examples presented should be considered illustrative and not as limitations of the disclosed or claimed apparatus and procedures. Although many of the examples presented here involve specific combinations of process steps or system elements, it should be clear that these steps and elements could be combined in other ways to achieve the same objectives. With regard to flowcharts, additional or fewer steps may be performed, and the steps, as shown, may be combined or further refined to achieve the processes described herein. Steps, elements, and features discussed only in connection with one embodiment are not intended to exclude a similar role in other embodiments.

[0047] As used here, "multiple" means two or more. As used here, a "set" of articles may contain one or more such articles. As used here, whether in the written description or the claims, the terms "comprising," "containing," "bearing," "exhibiting," "incorporating," "including," and the like are to be understood as open terms, i.e., with the meaning "containing, but not limited to." Only the transitional phrases "consisting of" and "essentially consisting of" are closed or semi-closed transitional phrases with respect to claims. The use of ordinal numbers such as "first," "second," "third," etc.The use of terms in claims to modify a claim element does not in itself indicate any priority, precedence, or order of one claim element over another, nor the chronological order in which steps of a process are carried out. Rather, these terms are used only to distinguish a claim element with a particular designation from an element with the same designation (except for the ordinal number). As used here, "and / or" means that the enumerated items are alternatives, but the alternatives can also include any combination of the enumerated items.

Claims

[1] Communication device (300), comprising: a triplexer (320, 400, 1100) with a common port and first, second and third branching ports; the triplexer includes (320, 400, 1100): a hybrid inductor-capacitor / surface acoustic wave (LC / SAW) high-pass filter (410, 600, 700) coupled between the common port (Com.) and the third branching port (B3); a hybrid (LC / SAW) low-pass filter (420, 800, 900, 1000) coupled between the common port (Com.) and an internal node; an LC high-pass filter (430, 1130) coupled between the internal node and the second branching port (B2); an LC low-pass filter (440, 1140) coupled between the internal node and the first branching port (B1). [2] Communication device (300) according to claim 1, comprising: wherein the (LC / SAW) low-pass filter (420, 800, 900, 1000) and the LC low-pass filter (440, 1140) are configured to allow radio frequency signals in a frequency range of 450 MHz to 960 MHz between the common port (Com.) and the first branch port (B1), The (LC / SAW) low-pass filter (420, 800, 900, 1000) and the LC high-pass filter (430, 1130) are configured to allow radio frequency signals in a frequency range of 1500 MHz to 2200 MHz between the common port (Com.) and the second branch port (B2), and The (LC / SAW) high-pass filter (410, 600, 700) is configured to allow radio frequency signals in a frequency range above 2300 MHz between the common port (Com.) and the third branch port (B3). [3] Communication device (300) according to claim 2, further comprising: an antenna (310) coupled to the common port (Com.); a first radio unit (330) coupled to the first branch port (B1), the first radio unit (330) being configured to communicate over one or more channels within the frequency range of 450 MHz to 960 MHz; a second radio (340) coupled to the second branch port (B2), the second radio (340) being configured to communicate over one or more channels within the frequency range of 1500 MHz to 2200 MHz; and a third radio (350) coupled to the third branch port (B3), wherein the third radio (350) is configured to communicate over one or more channels with frequencies above 2300 MHz. [4] Communication device (300) according to claim 2, wherein the LC / SAW low-pass filter (420, 800, 900, 1000) is configured to allow radio frequency signals in a frequency range from 450 MHz to 2200 MHz and to block radio frequency signals in a frequency range from 2300 MHz to at least 4000 MHz, and the LC / SAW high-pass filter (410, 600, 700) is configured to allow radio frequency signals to pass in a frequency range from 2300 MHz to at least 4000 MHz and to block radio frequency signals in a frequency range from 450 MHz to 2200 MHz. [5] Communication device (300) according to claim 1, wherein the LC / SAW high-pass filter (600, 700) comprises: an LC high-pass filter that defines a stopband and a passband separated by a crossover frequency region; and a SAW resonator (X1) connected in parallel to at least part of the LC high-pass filter, with a resonant frequency within the transition frequency region. [6] Communication device (300) according to claim 5, wherein the LC high-pass filter comprises two or more series capacitors (C1, C2, C3, C4) and two or more shunt inductors (L1, L2, L3) and the SAW resonator (X1) is connected in parallel with at least some of the two or more series capacitors (C1, C2, C3, C4). [7] Hybrid LC / SAW filter (700) for a communication device (300) according to claim 6, wherein The LC high-pass filter comprises two series capacitors (C1, C2) and two shunt inductors (L1, L2), the first SAW resonator (X1) is connected in parallel with the two series capacitors (C1, C2) and the hybrid LC / SAW filter (700) further comprises a second SAW resonator (X2) which is connected in parallel to one of the shunt inductors (L2). [8] Hybrid LC / SAW filter (600) for a communication device (300) according to claim 6, wherein the LC high-pass filter comprises four series capacitors (C1, C2, C3, C4) and three shunt inductors (L1, L2, L3) and the first SAW resonator (X1) is connected in parallel with three (C1, C2, C3) of the series capacitors (C1, C2, C3, C4). [9] Communication device (1100) according to claim 1, wherein the LC / SAW low-pass filter (800) comprises: a bridged-T circuit comprising two inductors (L4, L5) connected in series, a capacitor (C4) connected in parallel with the inductors (L4, L5) connected in series, and a SAW resonator (X3) connected to ground from a junction between the two inductors (L4, L5). [10] Communication device (1100) according to claim 9, further comprising: a second capacitor (C3) and a third inductor (L3) forming a low-pass filter section in series with the bridged-T circuit. [11] Hybrid LC / SAW high-pass filter (600, 700) for a communication device (300) according to claim 6, comprising: an LC high-pass filter defining a stopband and a passband separated by a crossover frequency region, wherein the LC high-pass filter comprises two or more series capacitors (C1, C2, C3, C4) and two or more shunt inductors (L1, L2, L3); and a first SAW resonator (X1) connected in parallel to at least one of the two or more series capacitors (C1, C2, C3) with a resonant frequency of the first SAW resonator (X1) within the transition frequency region. [12] Hybrid LC / SAW high-pass filter (600) according to claim 11, wherein the LC high-pass filter comprises four series capacitors (C1, C2, C3, C4) and three shunt inductors (L1, L2, L3) and the first SAW resonator (X1) is connected in parallel with three (C1, C2, C3) of the series capacitors (C21, C2, C3, C4). [13] Hybrid LC / SAW high-pass filter (700) according to claim 11, wherein The LC high-pass filter comprises two series capacitors (C1, C2) and two shunt inductors (L1, L2), the first SAW resonator (X1) is connected in parallel with the two series capacitors (C1, C2) and the hybrid LC / SAW filter (700) further comprises a second SAW resonator (X2) which is connected in parallel to one of the shunt inductors (L1, L2). [14] Hybrid LC / SAW low-pass filter (800) for a communication device (1100) according to claim 9, which defines a stopband and a passband separated by a transition frequency region, comprising: a bridged-T circuit, containing first and second inductors (L4, L5) connected in series, a first capacitor (C4) connected in parallel with the first and second inductors (L4, L5) connected in series, a SAW shunt resonator (X3) connected to ground via a junction between the first and second inductors (L4, L5), wherein a resonant frequency of the first SAW shunt resonator (X1) lies within the transition frequency region. [15] Hybrid LC / SAW low-pass filter (800) according to claim 14, further comprising: a second capacitor (C3) and a third inductor (L3) forming a low-pass filter section in series with the bridged-T circuit. [16] Communication device (300) according to claims 5 or 6, wherein The LC high-pass filter comprises two series capacitors (C1, C2) and two shunt inductors (L1, L2), the first SAW resonator (X1) is connected in parallel with the two series capacitors (C1, C2) and the hybrid LC / SAW filter (700) further comprises a second SAW resonator (X2) which is connected in parallel to one of the shunt inductors (L2). [17] Communication device (300) according to claims 1, 5 and 6, wherein the (LC / SAW) low-pass filter (420, 800, 900, 1000) and the LC low-pass filter (440, 1140) are configured to allow radio frequency signals in a frequency range of 450 MHz to 960 MHz between the common port (Com.) and the first branch port (P1), and wherein the (LC / SAW) low-pass filter (420, 800, 900, 1000) and the LC high-pass filter (430, 1130) are configured to allow radio frequency signals in a frequency range of 1500 MHz to 2200 MHz between the common port (Com.) and the second branch port (P2), and wherein the (LC / SAW) high-pass filter (410, 600, 700) is configured to allow radio frequency signals to pass through in a frequency range above 2300 MHz between the common port (Com.) and the third branch port (P3). [18] Communication device (300) according to claim 17, comprising an antenna (310) coupled to the common port (Com.); a first radio unit (330) coupled to the first branch port (P1), wherein the first radio unit (330) is configured to communicate over one or more channels within the frequency range of 450 MHz to 960 MHz; a second radio (340) coupled to the second branch port (P2), the second radio (340) being configured to communicate over one or more channels within the frequency range of 1500 MHz to 2200 MHz; and a third radio (350) coupled to the third branch port (P3), wherein the third radio (350) is configured to communicate over one or more channels with frequencies above 2300 MHz. [19] Communication device (300) according to claims 5 or 6 wherein the LC high-pass filter comprises four series capacitors (C1, C2, C3, C4) and three shunt inductors (L1, L2, L3) and the first SAW resonator (X1) is connected in parallel to three (C1, C2, C3) of the series capacitors (C1, C2, C3, C4). [20] Communication device (300) according to claims 1 and 9, comprising: wherein the (LC / SAW) low-pass filter (420, 800, 900, 1000) and the LC low-pass filter (440, 1140) are configured to allow radio frequency signals in a frequency range of 450 MHz to 960 MHz between the common port (Com.) and the first branch port (P1), and wherein The (LC / SAW) low-pass filter (420, 800, 900, 1000) and the LC high-pass filter (430, 1130) are configured to allow radio frequency signals in a frequency range of 1500 MHz to 2200 MHz between the common port (Com.) and the second branch port (P2), wherein The (LC / SAW) high-pass filter (410, 600, 700) is configured to allow radio frequency signals in a frequency range above 2300 MHz between the common port (Com.) and the third branch port (P3). [21] Communication device (300) according to claims 1 and 9, further comprising: an antenna (310) coupled to the common port (Com.); a first radio unit (330) coupled to the first branch port (P1), wherein the first radio unit (330) is configured to communicate over one or more channels within the frequency range of 450 MHz to 960 MHz; a second radio (340) coupled to the second branch port (P2), the second radio (340) being configured to communicate over one or more channels within the frequency range of 1500 MHz to 2200 MHz; and a third radio (350) coupled to the third branch port (P3), wherein the third radio (350) is configured to communicate over one or more channels with frequencies above 2300 MHz.

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