Front-end module

Abstract

To provide a high-frequency front-end module that is adaptable to carrier aggregation and enables easy design of a bandpass filter with a simple configuration.SOLUTION: A front-end module 1 includes a first elastic wave device that passes a first frequency band, a second elastic wave device that passes a second frequency band, a third elastic wave device that passes a third frequency band, a resonator, a first switch that switches on / off between an antenna terminal and the first elastic wave device, a second switch that switches on / off between the antenna terminal and the second elastic wave device, a third switch that switches on / off between the antenna terminal and the third elastic wave device, and a fourth switch that switches on / off between the antenna terminal and the resonator. The second and third frequency bands are higher frequency bands than the first frequency band, and the resonant frequency of the resonator is higher frequency than the first frequency band and lower frequency than the second and third frequency bands.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a high-frequency front-end module that transmits and receives communication signals of a plurality of communication bands.

Background Art

[0002] Mobile communication terminals represented by smartphones provide various telecommunication functions such as telephone, video, data, messaging, and broadcast. To realize these telecommunication functions, a high-frequency front-end module capable of using a plurality of communication bands with different frequency bands for each is essential.

[0003] As a high-frequency front-end module capable of using a plurality of communication bands, an electronic system circuit using carrier aggregation is known (see, for example, Patent Document 1).

[0004] FIG. 2C of Patent Document 1 describes an electronic system including one antenna, one diplexer, and two power amplifiers (a first power amplifier and a second power amplifier).

[0005] In the above electronic system, the diplexer is connected to the antenna. Also, in the above electronic system, each of the two power amplifiers is connected to the diplexer via a transmit / receive switch and a filter.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Front-end modules that support carrier aggregation often include three or more band-pass filters, but the design of each band-pass filter is difficult. According to the present disclosure, a front-end module that supports carrier aggregation with a simpler configuration and is easier to design each band-pass filter can be configured.

Means for Solving the Problem

[0008] The front-end module according to the present disclosure includes a first surface acoustic wave device connected to the antenna terminal and passing the first frequency band, a second surface acoustic wave device connected to the antenna terminal and passing the second frequency band, a third surface acoustic wave device connected to the antenna terminal and passing the third frequency band, a resonator connected to the antenna terminal, a first switch for performing on / off switching between the antenna terminal and the first surface acoustic wave device, a second switch for performing on / off switching between the antenna terminal and the second surface acoustic wave device, a third switch for performing on / off switching between the antenna terminal and the third surface acoustic wave device, a fourth switch for performing on / off switching between the antenna terminal and the resonator, and the second frequency band and the third frequency band are bands with higher frequencies than the first frequency band, a front-end module in which the resonance frequency of the resonator is higher than the first frequency band and lower than the second frequency band and the third frequency band.

[0009] In one aspect of the present disclosure, at least a part of the second frequency band and the third frequency band overlap or are adjacent to each other, at least one of the first switch to the third switch is turned on, and the second switch and the third switch are not turned on at the same time.

[0010] In one embodiment of the present disclosure, the fourth switch is turned on when the first switch is turned on and the second and third switches are turned off.

[0011] In one embodiment of the present disclosure, the resonator is divided into a first divided resonator and a second divided resonator in parallel, and the resonance frequencies of the first divided resonator and the second divided resonator are different frequencies.

[0012] The resonator is a SAW resonator. At least one of the second elastic wave device and the third elastic wave device is an elastic wave device including a SAW filter having a piezoelectric substrate. In one embodiment of the present disclosure, the resonator is formed on the piezoelectric substrate.

[0013] A fourth elastic wave device connected to the antenna terminal and passing a fourth frequency band; A fifth switch for performing on / off switching between the antenna terminal and the fourth elastic wave device; The fourth frequency band is a band having a lower frequency than the second frequency band. In one embodiment of the present disclosure, the fourth switch is turned on when the first switch or the fifth switch is turned on and the second and third switches are turned off.

[0014] In one embodiment of the present disclosure, the fourth switch is turned on when only the fifth switch is turned on.

[0015] In one embodiment of the present disclosure, the fourth switch is turned off when the third switch and the fifth switch are turned on.

[0016] In one embodiment of the present disclosure, a first inductor element connected in parallel between the first switch and the first elastic wave device is provided.

[0017] A second inductor element connected in series between the second switch and the second elastic wave device, and a third inductor element connected in series between the third switch and the third elastic wave device are provided in one form of the present disclosure.

[0018] One form of the present disclosure is to include a fourth inductor element connected in parallel between the fifth switch and the fourth elastic wave device.

Advantages of the Invention

[0019] According to the present disclosure, a front-end module corresponding to carrier aggregation that is easy to design a band-pass filter can be configured with a simpler configuration.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

[0021] Embodiments will be described with reference to the accompanying drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals. Redundant descriptions of such parts may be simplified or omitted.

[0022] Embodiment 1. FIG. 1 is a schematic diagram of the front-end module 1 in Embodiment 1. As shown in FIG. 1, the front-end module 1 includes an antenna terminal ANT, a first switch SW1, a second switch SW2, a third switch SW3, a fourth switch SW4, a first surface acoustic wave device BPF1, a second surface acoustic wave device BPF2, a third surface acoustic wave device BPF3, and a resonator R.

[0023] Each of the switches SW1 to SW4 switches on / off between the antenna terminal ANT and each of the surface acoustic wave devices BPF1 to BPF3 and the resonator R.

[0024] Each of the surface acoustic wave devices BPF1 to BPF3 is, for example, a band-pass filter configured to pass only an electrical signal in a desired frequency band among the applied electrical signals.

[0025] The first surface acoustic wave device BPF1 includes a first filter F1 and a second filter F2. The first filter F1 is, for example, a band-pass filter that passes a frequency band of 2110 MHz to 2170 MHz, which is the reception band of Band 1 and has a center frequency of 2140 MHz.

[0026] The second filter F2 is, for example, a band-pass filter that passes a frequency band of 1805 MHz to 1880 MHz, which is the reception band of Band 3 and has a center frequency of 1842.5 MHz.

[0027] The second surface acoustic wave device BPF2 is, for example, a band-pass filter that passes a frequency band of 2620 MHz to 2690 MHz, which is the reception band of Band 7 and has a center frequency of 2655 MHz.

[0028] The third surface acoustic wave device BPF3 is, for example, a band-pass filter that passes a frequency band of 2496 MHz to 2690 MHz, which is the reception band of Band 41 and has a center frequency of 2593 MHz.

[0029] The pass frequency bands of the second elastic wave device BPF2 and the third elastic wave device BPF3 partially overlap. Therefore, the second elastic wave device BPF2 and the third elastic wave device BPF3 are not used simultaneously. That is, the second switch SW2 and the third switch SW3 are not turned on simultaneously.

[0030] This is because significant impedance mismatches occur when elastic wave devices with partially overlapping frequencies are turned on simultaneously. Also, even if the frequencies do not overlap with each other, elastic wave devices with pass band frequencies that are close enough to each other to make impedance matching difficult are not used simultaneously.

[0031] For example, in the case of elastic wave devices whose pass band frequencies are only separated by about 25 MHz from each other, it can be said that they are close enough to make impedance matching difficult.

[0032] The equivalent input capacitance of the first elastic wave device BPF1 of the front-end module 1 in Embodiment 1, that is, the equivalent capacitance EC (Equivalent Capacitance) at a predetermined frequency, is configured to be smaller than the equivalent input capacitance (equivalent capacitance EC at a predetermined frequency) of the resonator R at frequencies outside the pass frequency band of the second elastic wave device BPF2 and outside the pass frequency band of the third elastic wave device BPF3.

[0033] The resonance frequency of the resonator R is set to, for example, 2470 MHz. The resonance frequency of the resonator R is higher than those of band 1 and band 3 and lower than those of band 7 and band 41.

[0034] FIG. 2 is a diagram showing the characteristics of the front-end module 1 in Embodiment 1 when the first switch SW1 and the fourth switch SW4 are turned on. As shown in FIG. 2, when the first switch SW1 and the fourth switch SW4 are turned on, a good impedance matching state on the antenna side can be obtained, good passing characteristics can be realized, and good attenuation characteristics can be obtained at the resonance frequency of the resonator R.

[0035] Further, the equivalent capacitance EC of the first surface acoustic wave device BPF1 is configured to be smaller than the equivalent input capacitances (equivalent capacitance EC at a predetermined frequency) of the second surface acoustic wave device BPF2 and the third surface acoustic wave device BPF3 at frequencies outside the passband of the first surface acoustic wave device BPF1.

[0036] Thereby, a good impedance matching state on the antenna side can be obtained regardless of which of the switches SW1 to SW4 is on.

[0037] Here, the equivalent capacitance EC is an equivalent input capacitance at a predetermined frequency, and when the reactance, which is the imaginary part of the input impedance of the filter, is X and the frequency is f, it is obtained by the following mathematical formula 1. Note that the predetermined frequency here is a frequency corresponding to outside the passband of the filter.

[0038]

Equation

[0039] Further, the equivalent input capacitances of the second surface acoustic wave device BPF2 and the third surface acoustic wave device BPF3 are configured to be equivalent at the center frequency of the first surface acoustic wave device BPF1. The equivalent input capacitance here means the equivalent input capacitance at a predetermined frequency obtained by the above mathematical formula 1.

[0040]

Table 1

[0041] Table 1 lists the usage status of each elastic wave device BPF1 to 3 and the on / off status of each switch SW1 to 4. When the first switch SW1 and the second switch SW2 are on, when only the second switch SW2 is on, or when only the third switch SW3 is on, the fourth switch SW4 is off.

[0042] Also, when only the first switch SW1 is on, the fourth switch SW4 is on. Also, at least one of the switches SW1 to 3 is on. Also, the second switch SW2 and the third switch SW3 do not turn on simultaneously.

[0043] For the front-end module corresponding to carrier aggregation, it is desirable that the equivalent input capacitance is the same in the connection pattern of any elastic wave device and the impedance is the same in any connection situation. For example, when Band 3 and Band 7 or Band 41 are used simultaneously, since Band 3 is configured considering the equivalent input capacitance of Band 7 or Band 41, it is not necessary to connect the resonator R.

[0044] If the equivalent input capacitances of Band 7 and Band 41 are equivalent, for example, at the center frequency of Band 3, the configuration of Band 3 considering the equivalent input capacitance is optimized. For example, in the case of Band 7 and Band 41, Band 3 is optimized with an equivalent input capacitance of 1.4 pF.

[0045] Since the pass frequency bands of Band 7 and Band 41 partially overlap and they are not used simultaneously, when Band 7 or Band 41 is used alone, Band 3 can be optimized according to its off state respectively.

[0046] When Band 1 or Band 3 is used alone, by connecting the resonator R instead of the equivalent input capacitance of Band 7 or Band 41, the equivalent input capacitance is considered, and as shown in FIG. 2, the characteristics of the optimized configuration of Band 1 or Band 3 can be exhibited without change.

[0047] FIG. 3 is a diagram showing the characteristics of the front-end module 1 in Embodiment 1 when the first switch SW1 and the second switch SW2 are turned on. As shown in FIG. 3, when the first switch SW1 and the second switch SW2 are turned on, a good impedance matching state on the antenna side can be obtained, and good passing characteristics can be realized.

[0048] FIG. 4 is a diagram showing the characteristics of the front-end module 1 in Embodiment 1 when the first switch SW1 and the third switch SW3 are turned on. As shown in FIG. 4, when the first switch SW1 and the third switch SW3 are turned on, a good impedance matching state on the antenna side can be obtained, and good passing characteristics can be realized.

[0049] FIGS. 5 to 7 show the characteristics of the front-end module 1 including the characteristics of the first surface acoustic wave device BPF1 that employs the reception band of band 34, which is a band-pass filter having a center frequency of 2117.5 MHz and passing a frequency band of 2110 MHz to 2125 MHz, as the first filter F1, and the reception band of band 39, which is a band-pass filter having a center frequency of 1900 MHz and passing a frequency band of 1880 MHz to 1920 MHz, as the second filter F2.

[0050] FIG. 5 is a diagram showing the characteristics (Part 2) of the front-end module 1 in Embodiment 1 when the first switch SW1 and the fourth switch SW4 are turned on.

[0051] As shown in FIG. 5, also in an example where another band is adopted as the first surface acoustic wave device BPF, when the first switch SW1 and the fourth switch SW4 are turned on, a good impedance matching state on the antenna side can be obtained, good passing characteristics can be realized, and good attenuation characteristics can be obtained at the resonance frequency of the resonator R.

[0052] FIG. 6 is a diagram showing the characteristics (part 2) of the front-end module 1 in Embodiment 1 when the first switch SW1 and the second switch SW2 are turned on. In FIG. 6, band 34 is adopted as the first filter F1, and band 39 is adopted as the second filter F2. As shown in FIG. 6, even in an example where another band is adopted as the first elastic wave device BPF, when the first switch SW1 and the second switch SW2 are turned on, a good impedance matching state on the antenna side can be obtained, and good passing characteristics can be realized.

[0053] FIG. 7 is a diagram showing the characteristics (part 2) of the front-end module 1 in Embodiment 1 when the first switch SW1 and the third switch SW3 are turned on. In FIG. 7, band 34 is adopted as the first filter F1, and band 39 is adopted as the second filter F2. As shown in FIG. 7, even in an example where another band is adopted as the first elastic wave device BPF, when the first switch SW1 and the third switch SW3 are turned on, a good impedance matching state on the antenna side can be obtained, and good passing characteristics can be realized.

[0054] FIG. 8 is a diagram showing a surface acoustic wave resonator used in a surface acoustic wave filter as an example of a band-pass filter. This surface acoustic wave resonator includes an Interdigital Transducer (IDT) 51 and a reflector 52 on a piezoelectric substrate 50. The IDT 51 has a pair of comb-shaped electrodes 51a arranged opposite to each other.

[0055] According to an example, the comb-shaped electrode 51a includes a plurality of electrode fingers 51b and a bus bar 51c connecting the plurality of electrode fingers 51b. The reflector 52 is provided on both sides of the IDT 51 so as to sandwich the IDT 51. The IDT 51 excites surface acoustic waves. The piezoelectric substrate 50 is, according to an example, a lithium tantalate substrate or a lithium niobate substrate. The IDT 51 and the reflector 52 are, according to an example, formed of an aluminum film or a copper film.

[0056] According to one example, the piezoelectric substrate 50 may be bonded to a support substrate such as a sapphire substrate, an alumina substrate, a spinel substrate, or a silicon substrate. Note that a protective film or a temperature compensation film covering the IDT 50 and the reflector 52 may be provided.

[0057] When any one of the elastic wave devices BPF1 to 3 is an elastic wave device using an elastic surface wave filter, the resonator R can be formed as a SAW resonator on the device chip of the elastic wave device using the elastic surface wave filter.

[0058] Also, when there are a plurality of elastic wave devices using an elastic surface wave filter, it is desirable to form it on the device chip of the elastic wave device in the frequency band closest to the resonance frequency of the resonator R. This is because the cut angle, thickness of the piezoelectric substrate, thickness of the IDT electrode, etc. of the device chip are optimized according to the frequency band. For example, the resonator R can be formed as a SAW resonator on the device chip on which the highest frequency filter using an elastic surface wave filter is arranged.

[0059] FIG. 9 is a diagram showing a piezoelectric thin film resonator used in an elastic wave filter as an example of a bandpass filter. This piezoelectric thin film resonator includes a piezoelectric film 57 on a substrate 55. A lower electrode 56 and an upper electrode 58 are provided so as to sandwich the piezoelectric film 57. A gap 59 is formed between the lower electrode 56 and the substrate 55. Then, the lower electrode 56 and the upper electrode 58 excite elastic waves in the thickness longitudinal vibration mode in the piezoelectric film 57. The lower electrode 56 and the upper electrode 58 are

[0060] According to one example, it is a metal film such as a ruthenium film. According to one example, the piezoelectric film 57 is an aluminum nitride film. According to one example, the substrate 55 is a silicon substrate, a sapphire substrate, an alumina substrate, a spinel substrate, or a glass substrate. According to another example, as an elastic wave resonator, a configuration different from the configurations shown in FIGS. 2 and 3 can be adopted.

[0061] The front-end module 1 of the above-described Embodiment 1 has a simpler configuration and constitutes a front-end module that can easily design a band-pass filter for carrier aggregation.

[0062] Embodiment 2. FIG. 10 is a schematic diagram of the front-end module 2 in Embodiment 2. As shown in FIG. 10, the front-end module 2 includes an antenna terminal ANT, a first switch SW1, a second switch SW2, a third switch SW3, a fourth switch SW4, a first surface acoustic wave device BPF1, a second surface acoustic wave device BPF2, a third surface acoustic wave device BPF3, a first inductor element L1, a second inductor element L2, a third inductor element L3, and a resonator R.

[0063] The first inductor element L1 is connected in parallel between the antenna terminal ANT and the first surface acoustic wave device BPF1. The second inductor element L2 is connected in series between the antenna terminal ANT and the second surface acoustic wave device BPF2. The third inductor element L3 is connected in series between the antenna terminal ANT and the third surface acoustic wave device BPF3. Other configurations are the same as those of the front-end module 1 in Embodiment 1. As described in Embodiment 1, the first surface acoustic wave device BPF1 is a surface acoustic wave device including a band-pass filter with a lower frequency than the second surface acoustic wave device BPF2 and the third surface acoustic wave device BPF3.

[0064] Since the first surface acoustic wave device BPF1 is a low-frequency filter in the front-end module 2, its capacitance component is relatively large. Therefore, it is desired to make the capacitance component of the first surface acoustic wave device BPF1 appear smaller. By connecting the inductor elements in parallel, all or part of the capacitance component of the first surface acoustic wave device BPF1 can be canceled out. For example, the first inductor element L1 can be 5 nH.

[0065] Since the second elastic wave device BPF2 and the third elastic wave device BPF3 are high-frequency filters, their capacitive components are relatively small. Therefore, it is desired to make the capacitive components of the second elastic wave device BPF2 and the third elastic wave device BPF3 appear larger. By connecting the inductor elements in series, the capacitive components of the second elastic wave device BPF2 and the third elastic wave device BPF3 can appear larger. As a result, the equivalent input capacitance can be easily adjusted. For example, the second inductor element L2 and the third inductor element L3 can be set to 3 nH.

[0066] The equivalent input capacitances of the second elastic wave device BPF2 and the third elastic wave device BPF3 are configured to be equivalent while taking into account the inductances of the second inductor element L2 and the third inductor element L3 at the center frequency of the first elastic wave device BPF1.

[0067] The front-end module 2 of the above-described Embodiment 2 constitutes a front-end module that can be easily designed for a band-pass filter while maintaining a simple configuration with only adjustment by an inductance element added, corresponding to carrier aggregation.

[0068] Embodiment 3. FIG. 11 is a schematic diagram of the resonator R of the front-end module 3 in Embodiment 3. As shown in FIG. 11, the resonator R can be divided in parallel into a first resonator R1 and a second resonator R2. The resonator R shown in FIG. 11 may be configured to be sandwiched between a pair of reflectors. Also, the resonance frequency of the first resonator R1 and the resonance frequency of the second resonator R2 can be set to different frequencies. For example, the difference between the resonance frequency of the first resonator R1 and the resonance frequency of the second resonator R2 can be in the range of 25 MHz to 50 MHz. This is to attenuate over a wide range while ensuring sufficient attenuation characteristics.

[0069] FIG. 12 is a diagram showing the characteristics of the front-end module 1 in Embodiment 3 when the first switch SW1 and the fourth switch SW4 are turned on.

[0070] As shown in FIG. 12, when the first switch SW1 and the fourth switch SW4 are turned on, a good impedance matching state on the antenna side is obtained, and while realizing good passing characteristics, the resonance frequency of the first resonator R1 and the resonance frequency of the second resonator R2 different from the resonance frequency of the first resonator R1 can obtain better attenuation characteristics with a wider range.

[0071] The front-end module 3 of the above-described Embodiment 3 constitutes a front-end module corresponding to carrier aggregation that can obtain better attenuation characteristics with a wider range while maintaining a simple configuration and is easy to design a band-pass filter.

[0072] Embodiment 4. FIG. 13 is a schematic diagram of the front-end module 4 in Embodiment 4. As shown in FIG. 13, in addition to the configurations of the front-end module 1 in Embodiment 1 and the front-end module 2 in Embodiment 2, the front-end module 4 includes a fourth surface acoustic wave device BPF4, a fifth switch SW5, and a fourth inductor element L4.

[0073] As shown in FIG. 13, the fifth switch SW5 switches on / off between the antenna terminal ANT and the fourth surface acoustic wave device BPF4. The fourth inductor element L4 is connected in parallel between the antenna terminal ANT and the fourth surface acoustic wave device BPF4.

[0074] As shown in FIG. 13, the first surface acoustic wave device BPF1 includes a first filter F1 and a second filter F2. Also, the fourth surface acoustic wave device BPF4 includes a third filter F3 and a fourth filter F4.

[0075] The first filter F1 is, for example, a band-pass filter in the reception band of band 3, having a center frequency of 1842.5 MHz and passing a frequency band of 1805 MHz to 1880 MHz.

[0076] The second filter F2 is, for example, a band-pass filter with a reception band of band 1, a center frequency of 2140 MHz, and passing a frequency band of 2110 MHz to 2170 MHz.

[0077] Here, as described above, the second surface acoustic wave device BPF2 has, for example, a reception band of band 7 and a center frequency of 2655 MHz. The third surface acoustic wave device BPF3 has, for example, a reception band of band 41 and a center frequency of 2593 MHz. The average of these center frequencies is 2624 MHz.

[0078] The first filter F1 and the first inductor element L1 are designed to have an equivalent input capacitance that satisfies the conditions described later, which is obtained by the above-mentioned formula 1, at an average center frequency of 2624 MHz. Similarly, the second filter F2 and the first inductor element L1 are designed to have an equivalent input capacitance that satisfies the conditions described later, which is obtained by the above-mentioned formula 1, at an average center frequency of 2624 MHz.

[0079] Since the first filter F1 is at a lower frequency than the second filter F2, the equivalent input capacitance is small at an average center frequency of 2624 MHz.

[0080] The third filter F3 is, for example, a band-pass filter with a reception band of band 39, a center frequency of 1900 MHz, and passing a frequency band of 1880 MHz to 1920 MHz.

[0081] The fourth filter F4 is, for example, a band-pass filter with a reception band of band 34, a center frequency of 2117.5 MHz, and passing a frequency band of 2110 MHz to 2125 MHz.

[0082] Here, the center frequencies of the first filter F1 (1805 MHz to 1880 MHz) and the third filter F3 (1880 MHz to 1920 MHz) are 1872 MHz.

[0083] The center frequencies of the second filter F2 (2110 MHz to 2170 MHz) and the fourth filter F4 (2110 MHz to 2125 MHz) are 2129 MHz.

[0084] The third filter F3 and the fourth inductor element L4 are designed to have an equivalent input capacitance that satisfies the conditions described below and is obtained by the above-mentioned formula 1 at an average center frequency of 2624 MHz.

[0085] Similarly, the fourth filter F4 and the fourth inductor element L4 are designed to have an equivalent input capacitance that satisfies the conditions described below and is obtained by the above-mentioned formula 1 at an average center frequency of 2624 MHz. Since the third filter F3 has a lower frequency than the fourth filter F4, the equivalent input capacitance is smaller at an average center frequency of 2624 MHz.

[0086] The equivalent input capacitance of the second surface acoustic wave device BPF2 is larger at the center frequency of 1872 MHz of the first filter F1 (1805 MHz to 1880 MHz) and the third filter F3 (1880 MHz to 1920 MHz) than the equivalent input capacitance at the average center frequency of 2624 MHz of each of the filters F1 to F4.

[0087] Also, the equivalent input capacitance of the third surface acoustic wave device BPF3 is larger at the center frequency of 1872 MHz of the first filter F1 (1805 MHz to 1880 MHz) and the third filter F3 (1880 MHz to 1920 MHz) than the equivalent input capacitance at the average center frequency of 2624 MHz of each of the filters F1 to F4.

[0088] Also, it is desirable that the absolute value of the impedance of the sum of the equivalent input capacitance of the second filter F2 or the fourth filter F4 at the center frequency of 1872 MHz of the first filter F1 (1805 MHz to 1880 MHz) and the third filter F3 (1880 MHz to 1920 MHz) and the equivalent input capacitance of the second surface acoustic wave device BPF2 is equal to the absolute value of the impedance of the first inductor element L1 at 1872 MHz.

[0089] Also, the absolute value of the impedance of the sum of the equivalent input capacitance of the first filter F1 or the third filter F3 at the center frequency 2129 MHz of the second filter F2 (2110 MHz to 2170 MHz) and the fourth filter F4 (2110 MHz to 2125 MHz), and the equivalent input capacitance of the second surface acoustic wave device BPF2, is desirably made equal to the absolute value of the impedance of the first inductor element L1 at 2129 MHz.

[0090] Also, the absolute value of the impedance of the sum of the equivalent input capacitance of the first filter F1 or the third filter F3 at the average center frequency 2624 MHz, and the equivalent input capacitance of the second filter F2 or the fourth filter F4, is desirably made equal to the absolute value of the impedance of the first inductor element L1 at 2624 MHz.

[0091] The fourth surface acoustic wave device BPF4 having a passband with a frequency lower than the frequency of the passband of the second surface acoustic wave device BPF2 has a relatively large capacitance component. For this reason, it is desired to make the capacitance component of the fourth surface acoustic wave device BPF4 appear smaller. By connecting an inductor element in parallel, all or part of the capacitance component of the fourth surface acoustic wave device BPF4 can be canceled out. As a result, regardless of which of the switches SW1 to 5 is on, a good impedance matching state on the antenna side can be obtained with the fourth inductor element L4 connected in parallel to the fourth surface acoustic wave device BPF4.

[0092]

Table 2

[0093] Table 2 shows a list of the usage status of each surface acoustic wave device BPF1 to 4 and the on / off status of each switch SW1 to 5. When the second switch SW2 and the fifth switch SW5 are on, or when the third switch SW3 and the fifth switch SW5 are on, the fourth switch SW4 is off.

[0094] Also, when only the fifth switch SW5 is on, the fourth switch SW4 is on. Also, at least one of the switches SW1 to 3 and 5 is on. Also, the second switch SW2 and the third switch SW3 do not turn on simultaneously. Also, the first switch SW1 and the fifth switch SW5 do not turn on simultaneously.

[0095] For example, when Band 39 and Band 7 or Band 41 are used simultaneously, since Band 39 is configured considering the equivalent input capacitance of Band 7 or Band 41, it is not necessary to connect the resonator R.

[0096] For example, when the equivalent input capacitances of Band 7 and Band 41 are equivalent at the center frequency of Band 39, the configuration of Band 39 considering the equivalent input capacitance is optimized. For example, in the case of Band 7 and Band 41, Band 39 is optimized with an equivalent input capacitance of 1.4 pF.

[0097] For example, since the pass frequency bands of Band 7 and Band 41 partially overlap and thus are not used simultaneously, when Band 7 or Band 41 is used alone, Band 39 may be optimized according to the off state.

[0098] For example, when Band 39 is used alone, by connecting the resonator R instead of the equivalent input capacitance of Band 7 or Band 41, the equivalent input capacitance is considered, and the characteristics of the optimized configuration of Band 39 can be exhibited without change.

[0099] Note that in the front-end module 4 of the fourth embodiment, for example, it is not assumed that Band 3 and Band 39 are used simultaneously. This is because the bands have frequencies in the pass bands that are close to each other to the extent that impedance matching becomes difficult.

[0100] The front-end module 4 of the above-described Embodiment 4 constitutes a front-end module that corresponds to carrier aggregation with a simpler configuration even in a configuration including six bands and is easy to design the equivalent capacitance of a band-pass filter.

[0101] Although some aspects of at least one embodiment have been described, it should be understood that various modifications, corrections, and improvements will readily occur to those skilled in the art. Such modifications, corrections, and improvements are intended to be part of this disclosure and are intended to be within the scope of this disclosure.

[0102] It should be understood that the embodiments of the methods and apparatuses described herein are not limited to the details of the structures and arrangements of the components described in the above description or illustrated in the accompanying drawings. The methods and apparatuses can be implemented in other embodiments and can be implemented or executed in various manners.

[0103] Specific implementation examples are provided herein for illustrative purposes only and are not intended to be limiting. Also, for example, the number of components mounted on a module is not limited to the number shown.

[0104] The expressions and terms used in this disclosure are for explanatory purposes and should not be regarded as limiting. The use of "including", "comprising", "having", "containing" and variations thereof herein means the inclusion of the items listed hereinafter and their equivalents as well as additional items.

[0105] References to "or (alternatively)" can be interpreted such that any term described using "or (alternatively)" indicates one, more than one, and all of the terms of the description.

[0106] References to front and back, top and bottom, left and right, horizontal and vertical, front and back are all for the purpose of convenience of description. Such references do not limit the components of this disclosure to any one positional or spatial orientation. Therefore, the above description and drawings are merely illustrative.

Description of Reference Numerals

[0107] 1, 2, 3, 4 front-end modules ANT antenna terminal, SW1~5 first switch~fifth switch L1~L4 first inductor element~fourth inductor element R resonator F1~F4 first filter~fourth filter

Claims

1. A first surface acoustic wave device connected to the antenna terminal and passing a first frequency band; A second surface acoustic wave device connected to the antenna terminal and passing a second frequency band; A third surface acoustic wave device connected to the antenna terminal and passing a third frequency band; A resonator connected to the antenna terminal; A first switch for performing on / off switching between the antenna terminal and the first surface acoustic wave device; A second switch for performing on / off switching between the antenna terminal and the second surface acoustic wave device; A third switch for performing on / off switching between the antenna terminal and the third surface acoustic wave device; A fourth switch for performing on / off switching between the antenna terminal and the resonator; Comprising; The second frequency band and the third frequency band are bands with higher frequencies than the first frequency band, A front-end module in which the resonance frequency of the resonator is higher than the first frequency band and lower than the second frequency band and the third frequency band.

2. At least one of the first switch to the third switch is on, and at least a part of the second frequency band and the third frequency band overlap or are adjacent to each other, and the second switch and the third switch are not on at the same time. The front-end module according to Claim 1.

3. When the first switch is on and the second switch and the third switch are off, the fourth switch is on. The front-end module according to Claim 1.

4. The resonator is divided into a first divided resonator and a second divided resonator in parallel, and the resonance frequencies of the first divided resonator and the second divided resonator are different frequencies. The front-end module according to Claim 1.

5. The resonator is a SAW resonator, At least one of the second surface acoustic wave device and the third surface acoustic wave device is a surface acoustic wave device including a SAW filter having a piezoelectric substrate, The resonator is formed on the piezoelectric substrate. The front-end module according to Claim 1.

6. A fourth surface acoustic wave device connected to the antenna terminal and passing a fourth frequency band; Comprising a fifth switch for performing on / off switching between the antenna terminal and the fourth surface acoustic wave device, The fourth frequency band is a band with a lower frequency than the second frequency band, The front-end module according to claim 1, wherein the fourth switch is turned on when the first switch or the fifth switch is turned on and the second switch and the third switch are turned off.

7. The front-end module according to claim 6, wherein the fourth switch is turned on when only the fifth switch is turned on.

8. The front-end module according to claim 6, wherein the fourth switch is turned off when the third switch and the fifth switch are turned on.

9. The front-end module according to claim 1, further comprising a first inductor element connected in parallel between the first switch and the first elastic wave device.

10. a second inductor element connected in series between the second switch and the second elastic wave device; a third inductor element connected in series between the third switch and the third elastic wave device The front-end module according to claim 1, comprising:

11. The front-end module according to claim 6, further comprising a fourth inductor element connected in parallel between the fifth switch and the fourth elastic wave device.

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