Front-end module

Abstract

To provide a front-end module compatible with carrier aggregation, which has a simpler configuration and makes it easier to design the equivalent capacitance of a bandpass filter.SOLUTION: A front-end module 1 includes first to third elastic wave devices BPF1 to BPF3 that are connected to an antenna terminal ANT and pass first to third frequency bands, a capacitor element C, first to third switches SW1 to SW3 which switch on / off between the antenna terminal and the first to third elastic wave devices, a fourth switch S4 which switches on / off with the capacitor element, and first to third inductor elements L1 to L3 which are connected in parallel between the first to third switches and the first to third elastic wave devices, respectively. The second and third frequency bands, which are bands higher in frequency than the first frequency band, are bands which at least partially overlap each other or are close to each other, and when the first to third switches are off, the fourth switch is turned on.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 typified 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 it is difficult to design the equivalent capacitance of each band-pass filter. According to the present disclosure, a front-end module corresponding to carrier aggregation with a simpler configuration and easier design of the equivalent capacitance of the 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 capacitor element 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 capacitor element, a first inductor element connected in parallel between the first switch and the first surface acoustic wave device, a second inductor element connected in series between the second switch and the second surface acoustic wave device, a third inductor element connected in series between the third switch and the third surface acoustic wave device and the second frequency band and the third frequency band are bands with higher frequencies than the first frequency band, at least a part of the second frequency band and the third frequency band overlap, or they are adjacent bands to each other, when the first switch is on, and the second switch and a front-end module in which the fourth switch is turned on when the third switch is turned off.

[0009] In one embodiment of the present disclosure, 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 simultaneously.

[0010] In one embodiment of the present disclosure, the equivalent input capacitance of the first surface acoustic wave device is smaller than the equivalent input capacitance of the capacitor element at frequencies outside the second frequency band and frequencies outside the third frequency band.

[0011] In one embodiment of the present disclosure, the equivalent input capacitance of the first surface acoustic wave device is smaller than the equivalent input capacitance of the second surface acoustic wave device and the equivalent input capacitance of the third surface acoustic wave device at frequencies outside the first frequency band.

[0012] In one embodiment of the present disclosure, the equivalent input capacitance of the second surface acoustic wave device and the equivalent input capacitance of the third surface acoustic wave device are equal at the center frequency of the first frequency band.

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

[0016] In one aspect of the present disclosure, a fourth inductor element is provided, which is connected in parallel between the fifth switch and the fourth surface acoustic wave device.

[0017] In one aspect of the present disclosure, the equivalent input capacitance of the second surface acoustic wave device and the equivalent input capacitance of the third surface acoustic wave device are equal at the center frequency of the first frequency band and equal at the center frequency of the fourth frequency band.

[0018] The first surface acoustic wave device includes a first filter that passes frequency band part 1 of the first frequency band, and a second filter that passes frequency band part 2 of the first frequency band, where frequency band part 2 has a higher frequency than frequency band part 1. In one aspect of the present disclosure, the equivalent input capacitance of the first filter is smaller than the equivalent input capacitance of the second filter at the average center frequency, which is the average of the center frequencies of the second frequency band and the third frequency band.

[0019] The fourth surface acoustic wave device includes a third filter that passes frequency band part 3 of the fourth frequency band, and a fourth filter that passes frequency band part 4 of the fourth frequency band, where frequency band part 4 has a higher frequency than frequency band part 3. In one aspect of the present disclosure, the equivalent input capacitance of the third filter is smaller than the equivalent input capacitance of the fourth filter at the average center frequency, which is the average of the center frequencies of the second frequency band and the third frequency band.

Advantages of the Invention

[0020] According to the present disclosure, a front-end module corresponding to carrier aggregation can be configured with a simpler structure, which is easy to design the equivalent capacitance of the band-pass filter.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0022] The embodiments will be described with reference to the accompanying drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals. The redundant description of such parts may be simplified or omitted.

[0023] 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 elastic - wave device BPF1, a second elastic - wave device BPF2, a third elastic - wave device BPF3, a first inductor element L1, a second inductor element L2, a third inductor element L3, and a capacitor element C.

[0024] 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 capacitor element C. 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.

[0025] 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. The first surface acoustic wave device BPF1 is, for example, the reception band of band 3, has a center frequency of 1842.5 MHz, and is a band-pass filter that passes a frequency band of 1805 MHz to 1880 MHz.

[0026] The second surface acoustic wave device BPF2 is, for example, the reception band of band 7, has a center frequency of 2655 MHz, and is a band-pass filter that passes a frequency band of 2620 MHz to 2690 MHz. The third surface acoustic wave device BPF3 is, for example, the reception band of band 41, has a center frequency of 2593 MHz, and is a band-pass filter that passes a frequency band of 2496 MHz to 2690 MHz.

[0027] A part of the pass frequency bands of the second surface acoustic wave device BPF2 and the third surface acoustic wave device BPF3 overlap. For this reason, the second surface acoustic wave device BPF2 and the third surface acoustic wave device BPF3 are not used simultaneously. That is, the second switch SW2 and the third switch SW3 do not turn on simultaneously.

[0028] This is because a significant impedance mismatch occurs when surface acoustic wave devices with overlapping frequencies are turned on simultaneously. Also, even if the frequencies do not overlap with each other, surface acoustic wave devices having frequencies in pass bands close to each other are not used simultaneously to such an extent that impedance matching becomes difficult.

[0029] For example, in the case of surface acoustic wave devices where the frequencies in the passband are only about 25 MHz apart from each other, it can be said that they are close enough to make impedance matching difficult.

[0030] Since the first surface acoustic wave device BPF1 is a low-frequency filter in the front-end module 1, the 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.

[0031] Since the second surface acoustic wave device BPF2 and the third surface acoustic wave device BPF3 are high-frequency filters, the capacitance components are relatively small. Therefore, it is desired to make the capacitance components of the second surface acoustic wave device BPF2 and the third surface acoustic wave device BPF3 appear larger. By connecting the inductor elements in series, the capacitance components of the second surface acoustic wave device BPF2 and the third surface acoustic wave device BPF3 can be made to appear larger. Thereby, the equivalent input capacitance can be easily adjusted. For example, the second inductor element L2 and the third inductor element L3 can be 3 nH.

[0032] The equivalent input capacitance of the first surface acoustic 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 capacitor element C at frequencies outside the pass frequency band of the second surface acoustic wave device BPF2 and outside the pass frequency band of the third surface acoustic wave device BPF3.

[0033] Thereby, regardless of which of the switches SW1 to 4 is on, a good impedance matching state on the antenna side can be obtained by the first inductor element L1 connected in parallel with the first surface acoustic wave device BPF1.

[0034] Also, the equivalent capacitance EC of the first elastic wave device BPF1 is configured to be smaller than the equivalent input capacitances (equivalent capacitance EC at a predetermined frequency) of the second elastic wave device BPF2 and the third elastic wave device BPF3 at frequencies outside the passband of the first elastic wave device BPF1.

[0035] Thereby, regardless of which of the switches SW1 to 4 is on, a good impedance matching state on the antenna side can be obtained by the first inductor element L1 connected in parallel to the first elastic wave device BPF1.

[0036] 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 formula (1). Note that the predetermined frequency here is a frequency corresponding to outside the passband of the filter.

[0037]

Equation

[0038] Also, 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. The equivalent input capacitance here means the equivalent input capacitance at a predetermined frequency obtained by the above formula (1).

[0039]

Table 1

[0040] 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.

[0041] 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 are not on at the same time.

[0042] 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 capacitor element C.

[0043] When the equivalent input capacitances of Band 7 and Band 41 are equivalent 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.

[0044] 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 3 may be optimized according to the off state respectively.

[0045] When Band 3 is used alone, by connecting the capacitor element C 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 3 can be exhibited without change.

[0046] FIG. 2 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.

[0047] 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 a surface acoustic wave. According to an example, the piezoelectric substrate 50 is a lithium tantalate substrate or a lithium niobate substrate. According to an example, the IDT 51 and the reflector 52 are formed of an aluminum film or a copper film.

[0048] According to an 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.

[0049] FIG. 3 is a diagram showing a piezoelectric thin film resonator used in an elastic wave filter as an example of a band-pass 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 an elastic wave in the thickness longitudinal vibration mode in the piezoelectric film 57. The lower electrode 56 and the upper electrode 58 are

[0050] According to an example, a metal film such as a ruthenium film. According to an example, the piezoelectric film 57 is an aluminum nitride film. According to an 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 may be adopted.

[0051] The front-end module 1 of the above-described Embodiment 1 has a simpler configuration and constitutes a front-end module corresponding to carrier aggregation in which the equivalent capacitance of the band-pass filter is easy to design.

[0052] Embodiment 2. FIG. 4 is a schematic diagram of the front-end module 2 in Embodiment 2. As shown in FIG. 4, the front-end module 2 includes, in addition to the configuration of the front-end module 1 in Embodiment 1, a fourth surface acoustic wave device BPF4, a fifth switch SW5, and a fourth inductor element L4.

[0053] 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.

[0054] The fourth surface acoustic wave device BPF4 is, for example, a band-pass filter having a reception band of band 39, a center frequency of 1900 MHz, and passing a frequency band of 1880 MHz to 1920 MHz. That is, the frequency of the pass band of the fourth surface acoustic wave device BPF4 is lower than the frequency of the pass band of the second surface acoustic wave device BPF2. For example, the inductance of the fourth inductor element L4 can be 4.8 nH.

[0055] The fourth surface acoustic wave device BPF4 having a pass band with a frequency lower than the frequency of the pass band of the second surface acoustic wave device BPF2 has a relatively large capacitance component. Therefore, 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. Thereby, a good impedance matching state on the antenna side can be obtained by the fourth inductor element L4 connected in parallel to the fourth surface acoustic wave device BPF4 regardless of which of the switches SW1 to SW5 is on.

[0056]

Table 2

[0057] Table 2 lists the usage status of each elastic 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.

[0058] 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 are not on at the same time. Also, the first switch SW1 and the fifth switch SW5 are not on at the same time.

[0059] 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 capacitor element C.

[0060] 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.

[0061] Since the pass frequency bands of Band 7 and Band 41 partially overlap and thus they are not used simultaneously, when Band 7 or Band 41 is used alone, Band 39 may be optimized according to the off state respectively.

[0062] When Band 39 is used alone, by connecting the capacitor element C 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.

[0063] In the front-end module 2 of the second embodiment, it is not assumed that bands 3 and 39 are used simultaneously. This is because the bands have frequencies in the passbands that are close to each other to such an extent that impedance matching becomes difficult.

[0064] As another example of use, the first surface acoustic wave device BPF1 may be 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.

[0065] The fourth surface acoustic wave device BPF4 may be a band-pass filter that passes a frequency band of 2110 MHz to 2125 MHz, which is the reception band of band 34 and has a center frequency of 2117.5 MHz.

[0066] The front-end module 2 of the above-described second embodiment constitutes a front-end module that has a simpler configuration and is suitable for carrier aggregation in which the equivalent capacitance of the band-pass filter is easy to design.

[0067] Embodiment 3. FIG. 5 is a schematic diagram of the front-end module 3 in Embodiment 3. As shown in FIG. 5, in addition to the configuration of the front-end module 2 in Embodiment 2, the first surface acoustic wave device BPF1 includes a first filter F1 and a second filter F2. Further, the fourth surface acoustic wave device BPF4 includes a third filter F3 and a fourth filter F4.

[0068] The first filter F1 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.

[0069] The second filter F2 is, for example, a band-pass filter that has a reception band of band 1, a center frequency of 2140 MHz, and passes a frequency band of 2110 MHz to 2170 MHz.

[0070] Here, as described above, the second SAW device BPF2 has, for example, a reception band of band 7 and a center frequency of 2655 MHz. The third SAW 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.

[0071] The first filter F1 and the first inductor element L1 are designed to have an equivalent input capacitance that satisfies the conditions described later and 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 and is obtained by the above-mentioned formula 1 at an average center frequency of 2624 MHz.

[0072] 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.

[0073] The third filter F3 is, for example, a band-pass filter that has a reception band of band 39, a center frequency of 1900 MHz, and passes a frequency band of 1880 MHz to 1920 MHz.

[0074] The fourth filter F4 is, for example, a band-pass filter that has a reception band of band 34, a center frequency of 2117.5 MHz, and passes a frequency band of 2110 MHz to 2125 MHz.

[0075] 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.

[0076] 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.

[0077] The third filter F3 and the fourth inductor element L4 are designed to have an equivalent input capacitance that satisfies the conditions described later and is obtained by the above-mentioned formula 1 at an average center frequency of 2624 MHz.

[0078] Similarly, the fourth filter F4 and the fourth inductor element L4 are designed to have an equivalent input capacitance that satisfies the conditions described later 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.

[0079] 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.

[0080] 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.

[0081] 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 and the equivalent input capacitance of the second surface acoustic wave device BPF2 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) is equal to the absolute value of the impedance of the first inductor element L1 at 1872 MHz.

[0082] Further, 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.

[0083] 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.

[0084] The front-end module 3 of the above-described Embodiment 3 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 the band-pass filter.

[0085] 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.

[0086] 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.

[0087] 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 the module is not limited to the number shown in the drawings.

[0088] The expressions and terms used in this disclosure are for illustrative 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.

[0089] References to "or (or)" can be construed such that any term described using "or (or)" indicates one, more than one, and all of the terms of the description.

[0090] References to front, back, left, right, top, bottom, vertical, horizontal, front, and back are all for the 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

[0091] 1, 2, 3 Front-end modules ANT Antenna terminal, SW1~5 First switch~Fifth switch L1~L4 First inductor element~Fourth inductor element C Capacitor element F1~F4 First filter~Fourth filter

Claims

1. A first surface acoustic wave device connected to an 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 capacitor element 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 capacitor element; A first inductor element connected in parallel between the first switch and the first surface acoustic wave device; A second inductor element connected in series between the second switch and the second surface acoustic wave device; A third inductor element connected in series between the third switch and the third surface acoustic wave device and comprising: The second frequency band and the third frequency band are bands with higher frequencies than the first frequency band; The second frequency band and the third frequency band are bands where at least a part of the bands overlap or are adjacent to each other; A front-end module in which the fourth switch is turned on when the first switch is turned on and when the second switch and the third switch are turned off.

2. The front-end module according to claim 1, wherein 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 simultaneously.

3. The front-end module according to claim 1, wherein the equivalent input capacitance of the first surface acoustic wave device is smaller than the equivalent input capacitance of the capacitor element at frequencies outside the second frequency band and frequencies outside the third frequency band.

4. The front-end module according to claim 1, wherein the equivalent input capacitance of the first surface acoustic wave device is smaller than the equivalent input capacitance of the second surface acoustic wave device and the equivalent input capacitance of the third surface acoustic wave device at frequencies outside the first frequency band.

5. The front-end module according to claim 1, wherein the equivalent input capacitance of the second surface acoustic wave device and the equivalent input capacitance of the third surface acoustic wave device are equal at the center frequency of the first frequency band.

6. A fourth surface acoustic 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 surface acoustic wave device, The fourth frequency band is a band having 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 when 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 6, further comprising a fourth inductor element connected in parallel between the fifth switch and the fourth surface acoustic wave device.

10. The equivalent input capacitance of the second surface acoustic wave device and the equivalent input capacitance of the third surface acoustic wave device are equal at the center frequency of the first frequency band and equal at the center frequency of the fourth frequency band. The front-end module according to claim 6.

11. The first surface acoustic wave device includes a first filter that passes a first frequency band of the first frequency band and a second filter that passes a second frequency band that is higher in frequency than the first frequency band of the first frequency band. The equivalent input capacitance of the first filter is smaller than the equivalent input capacitance of the second filter at an average center frequency that is an average of the center frequency of the second frequency band and the center frequency of the third frequency band. The front-end module according to claim 1 or claim 6.

12. The fourth surface acoustic wave device includes a third filter that passes a third frequency band of the fourth frequency band and a fourth filter that passes a fourth frequency band that is higher in frequency than the third frequency band of the fourth frequency band. The equivalent input capacitance of the third filter is smaller than the equivalent input capacitance of the fourth filter at an average center frequency that is an average of the center frequency of the second frequency band and the center frequency of the third frequency band. The front-end module according to claim 6.

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