Elastic wave device and electronic apparatus

Abstract

The embodiment of the invention relates to an elastic wave device and electronic equipment. The elastic wave device comprises an input terminal; an output terminal; a first multi-mode resonator connected in series between the input terminal and the output terminal; a second multi-mode resonator connected in series between the input terminal and the output terminal, and connected in parallel with the first multi-mode resonator; wherein the area of the first multi-mode resonator is larger than or equal to 1.6 times of the area of the second multi-mode resonator, and the center frequency of the first multi-mode resonator is smaller than the center frequency of the second multi-mode resonator. The elastic wave device provided by the embodiment of the invention can meet the wide-band requirement.

Description

Technical Field

[0001] The present invention relates to the field of filters, and particularly to an elastic wave device and an electronic device. Background Art

[0002] In modern wireless communication systems, a duplexer or a multiplexer is a key component for implementing frequency division duplexing (FDD) and multi-band operation. Both the duplexer and the multiplexer are composed of elastic wave devices, and the duplexer or the multiplexer can be used to separate receive (Rx) and transmit (Tx) signals to ensure that the two can coexist in the same device without interfering with each other.

[0003] In the prior art, the design of elastic wave devices mainly adopts two structures: a trapezoidal structure and a DMS (Double-mode SAW, dual-mode surface acoustic wave) type filter. Among them, the DMS type filter has significant advantages in low-end suppression performance and miniaturization, and is widely used in the design of filters and duplexers. However, the traditional DMS type filter has the problem of narrow bandwidth, which limits its performance in broadband applications. Summary of the Invention

[0004] Therefore, in order to overcome at least some of the defects and deficiencies of the above prior art, an embodiment of the present invention proposes an elastic wave device to meet the requirements of a wide frequency band.

[0005] On the one hand, an elastic wave device proposed by an embodiment of the present invention includes: an input terminal; an output terminal; a first multimode resonator connected in series between the input terminal and the output terminal; a second multimode resonator connected in series between the input terminal and the output terminal and connected in parallel with the first multimode resonator; wherein, the area of the first multimode resonator is greater than or equal to 1.6 times the area of the second multimode resonator, and the center frequency of the first multimode resonator is less than the center frequency of the second multimode resonator.

[0006] On the second hand, another embodiment of the present invention proposes an electronic device, which includes the elastic wave device as described above.

[0007] As can be seen from the above, the above technical features of the present invention can have the following beneficial effects: By setting the first multimode resonator and the second multimode resonator to be connected in parallel, and making the area of the first multimode resonator greater than or equal to 1.6 times the area of the second multimode resonator, the bandwidth of the elastic wave device can be increased or decreased. Moreover, the first DMS type filter and the second DMS type filter with basically the same structure and different areas are used for passband synthesis in parallel, which has no obvious influence on the insertion loss while expanding the bandwidth, and has a high suppression effect and good selectivity. Brief Description of the Drawings

[0008] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0009] Figure 1 It is a circuit schematic diagram of an elastic wave device provided by the present invention.

[0010] Figure 2a For Figure 1 It is a simplified top view of the circuit configuration of the first multimode resonator type elastic wave filter involved.

[0011] Figure 2b For Figure 1 It is a simplified top view of the circuit configuration of the second multimode resonator type elastic wave filter involved.

[0012] Figure 3a It is a curve graph comparing the insertion loss characteristics of the first multimode resonator, the second multimode resonator, and the combination of the first multimode resonator and the second multimode resonator of the present invention.

[0013] Figure 3b It is a curve graph comparing the attenuation characteristics of the first multimode resonator, the second multimode resonator, and the combination of the first multimode resonator and the second multimode resonator of the present invention.

[0014] Figure 4a It is a curve graph comparing the insertion loss characteristics of the first multimode resonator and the second multimode resonator of the present invention under different area ratios.

[0015] Figure 4b It is a curve graph comparing the attenuation characteristics of the first multimode resonator and the second multimode resonator of the present invention under different area ratios.

[0016] Figure 5a It is a curve graph comparing the insertion loss characteristics of Example 2 and the comparative example obtained by combining the first multimode resonator and the second multimode resonator of the present invention when their center frequencies are relatively close.

[0017] Figure 5b It is a curve graph comparing the insertion loss characteristics of Example 3 and the comparative example obtained by combining the first multimode resonator and the second multimode resonator of the present invention when their center frequencies are relatively far apart.

[0018] Figure 6a It is a circuit schematic diagram of the first multimode resonator and the second multimode resonator of the present invention when their areas are the same.

[0019] Figure 6b Schematic diagram of the circuit when the area of the first multimode resonator of the present invention is 1.6 times the area of the second multimode resonator 40.

[0020] Figure 6c Schematic diagram of the circuit when the area of the first multimode resonator of the present invention is 2 times the area of the second multimode resonator 40.

[0021] Figure 7 Cross-sectional schematic diagram of an electronic device provided by the second embodiment of the present invention.

[0022]

Explanation of the reference numerals of the drawings

[0023] 1: Elastic wave device; 10: Input terminal; 20: Output terminal; 30: First multimode resonator; 31: First reflector; 32: Second reflector; 33: First interdigital transducer structure; 34: First bus bar; 40: Second multimode resonator; 41: Third reflector; 42: Fourth reflector; 43: Second interdigital transducer structure; 44: Second bus bar; 50: Ground terminal; 61: First series resonator; 62: Second series resonator; 63: First parallel resonator; 64: Second parallel resonator; 100: Electronic device; 110: Wiring substrate; 111: Inductive element; 112: Sealing portion; 113: External connection terminal. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

The first embodiment

[0025] As Figure 1 shown, the embodiment of the present invention provides an elastic wave device 1. Specifically, the elastic wave device 1 provided by the embodiment of the present invention includes, for example: an input terminal 10, an output terminal 20, a first multimode resonator 30, and a second multimode resonator 40.

[0026] Specifically, the first multimode resonator 30 is connected in series between the input terminal 10 and the output terminal 20. The second multimode resonator 40 is connected in series between the input terminal 10 and the output terminal 20 and is connected in parallel with the first multimode resonator 30. The first multimode resonator 30 and the second multimode resonator 40 can be, for example, DMS type filters. Among them, the frequencies of both the first multimode resonator 30 and the second multimode resonator 40 are different. In this embodiment, the first multimode resonator 30 is a DMS type filter with a lower frequency, and the second multimode resonator 40 is a DMS type filter with a higher frequency.

[0027] Among them, the area of the first multimode resonator 30 is greater than or equal to 1.6 times the area of the second multimode resonator 40, and the center frequency of the first multimode resonator 30 is less than the center frequency of the second multimode resonator 40. For example, the area of the first multimode resonator 30 is greater than or equal to 1.6 times the area of the second multimode resonator 40. As Figure 1 shown, the area of the first multimode resonator 30 on the chip is greater than or equal to 1.6 times the area of the second multimode resonator 40 on the circuit board, so that the input equivalent capacitance of the first multimode resonator 30 can be more than 1.6 times the input equivalent capacitance of the second multimode resonator 40. As Figure 1 shown, in this diagram, the area of the first multimode resonator 30 is larger than the area of the second multimode resonator 40. For the first multimode resonator 30 and the second multimode resonator 40 with different area ratios, their insertion losses and bandwidths are different. As Figure 4a - Figure 4b and Figure 6a - Figure 6c shown, the curve of the comparative example represents that the area ratio of the first multimode resonator 30 to the second multimode resonator 40 is 1:1, and its specific circuit diagram can be as Figure 6a shown, that is, the area of the first multimode resonator 30 is the same as the area of the second multimode resonator 40. The curve of Embodiment 1 represents that the area of the first multimode resonator 30 is 2 times the area of the second multimode resonator 40, and the specific circuit diagram can be as Figure 6c shown. The curve of Embodiment 2 represents that the area of the first multimode resonator 30 is 1.6 times the area of the second multimode resonator 40, and the specific circuit diagram is as Figure 6b shown. As Figure 4a - Figure 4b shown, in the case of Embodiment 1, its characteristics are the best. The bandwidth of Embodiment 2 is about 70.7 MHz. The bandwidth of Embodiment 1 is about 2.4 MHz wider than the bandwidth of Embodiment 2, and the insertion loss of Embodiment 1 is improved by 0.5 dB compared with that of Embodiment 2. In addition, from Figure 4b it can be seen that by increasing the area ratio between the first multimode resonator 30 and the second multimode resonator 40, the attenuation of the elastic wave device 1 in Embodiment 1 is reduced, making the attenuation characteristics of the elastic wave device 1 better.

[0028] Among them, the calculation methods of the center frequencies of the first multimode resonator 30 and the second multimode resonator 40 can be, for example, the calculation methods in the prior art. Generally speaking, the calculation of the center frequency is, for example, Of course, in some cases, it can also be simply the average value Such as Figure 3a - Figure 3b As shown, in the figure, DMS1 is the first multimode resonator 30, and DMS2 is the second multimode resonator 40, which are combined into a circuit structure formed by the parallel connection of the first multimode resonator 30 and the second multimode resonator 40. From Figure 3a - Figure 3b It can be known that the center frequency of DMS1 is less than the center frequency of DMS2. Secondly, since the passband frequency coverage range of a single DMS-type resonator is relatively narrow, after the first multimode resonator 30 and the second multimode resonator 40 with different areas are connected in parallel, the synthesized bandwidth of the passband is 758 MHz - 821 MHz, and its passband covers Band 28Rx-full band passband: 758 MHz - 803 MHz and Band 20Rx passband: 791 MHz - 821 MHz. The edge loss of its passband is less than 2.5 dB.

[0029] Since the bandwidth of the DMS-type filter in the prior art is relatively narrow, in this application, by connecting the first multimode resonator 30 and the second multimode resonator 40 in parallel and synthesizing the passbands of the two DMS-type filters, the bandwidth after the passband synthesis can cover the passbands of the duplexer of Band 28Rx-full band and Band 20Rx. And by adjusting the area of the first multimode resonator 30 to more than 1.6 times the area of the second multimode resonator 40, the characteristics of the elastic wave device 1 after the passband synthesis of the first multimode resonator 30 and the second multimode resonator 40 can be further improved. Thus, when the elastic wave device 1 meets the requirement of a relatively wide broadband, it can also reduce the insertion loss and enhance the attenuation characteristics, thereby improving the device performance of the elastic wave device 1.

[0030] Furthermore, the area of the first multimode resonator 30 does not exceed 3 times the area of the second multimode resonator 40.

[0031] Furthermore, the elastic wave device 1 also includes, for example, a first series resonator 61 and a second series resonator 62.

[0032] Specifically, one end of the first series resonator 61 is connected in series to the input terminal 10, and the other end of the first series resonator 61 is respectively connected in series to the input ends of the first multimode resonator 30 and the second multimode resonator 40; one end of the second series resonator 62 is respectively connected in series to the output ends of the first multimode resonator 30 and the second multimode resonator 40, and the other end of the second series resonator 62 is connected in series to the output terminal 20. In this embodiment, by respectively providing the first series resonator 61 and the second series resonator 62 at the parallel input end and the parallel output end of the first multimode resonator 30 and the second multimode resonator 40, the elastic wave device can not only improve the performance but also maintain good insertion loss performance and high suppression performance.

[0033] Furthermore, the elastic wave device 1 also includes, for example: a ground terminal 50, a first parallel resonator 63, and a second parallel resonator 64.

[0034] Specifically, one end of the first parallel resonator 63 is connected in parallel between the second series resonator 62 and the output terminal 20, and the other end of the first parallel resonator 63 is electrically connected to the ground terminal 50; one end of the second parallel resonator 64 is connected in parallel between the second series resonator 62 and the output terminal 20, and the other end of the second parallel resonator 64 is electrically connected to the ground terminal 50; wherein, the first parallel resonator 63 and the second parallel resonator 64 are connected in parallel. In this embodiment, by connecting the first parallel resonator 63 and the second parallel resonator 64 in parallel between the second series resonator 62 and the output terminal 20, the elastic wave device 1 can not only improve the performance but also maintain good insertion loss performance and high suppression performance.

[0035] Furthermore, the first parallel resonator 63 is closer to the first multimode resonator 30 than the second parallel resonator 64, and the area of the first parallel resonator 63 exceeds 1.6 times the area of the second parallel resonator 64.

[0036] Furthermore, the center frequency of the second multimode resonator 40 is 1.04 - 1.06 times the center frequency of the first multimode resonator 30. In this embodiment, the center frequency of the second multimode resonator 40 can be, for example, 806.5 MHz, and the center frequency of the first multimode resonator 30 can be, for example, 773.5 MHz. As Figure 5a - Figure 5b shown, where in Figure 5aAmong them, the curve represented by Embodiment 3 is the bandwidth after the parallel connection of the first multimode resonator 30 and the second multimode resonator 40 when the center frequency of the second multimode resonator 40 is closer to the center frequency of the first multimode resonator 30 (that is, when the center frequency of the second multimode resonator 40 is relatively close to the center frequency of the first multimode resonator 30). The curve represented by Comparative Example 2 is the simulation result of Band 28Rx-full band. From Figure 5a it can be seen that if the center frequencies of the first multimode resonator 30 and the second multimode resonator 40 become closer, it will cause spurious phenomena in the bandwidth of the elastic wave device after the parallel connection of the first multimode resonator 30 and the second multimode resonator 40. As Figure 5b shown, the curve represented by Embodiment 3 is the bandwidth after the parallel connection of the first multimode resonator 30 and the second multimode resonator 40 when the center frequency of the second multimode resonator 40 is farther from the center frequency of the first multimode resonator 30 (that is, when the center frequency of the second multimode resonator 40 is relatively far from the center frequency of the first multimode resonator 30). The curve represented by Comparative Example 2 is the simulation result of Band 28Rx-full band. If the center frequency of the second multimode resonator 40 is farther from the center frequency of the first multimode resonator 30, spurious phenomena will also occur in the bandwidth, and there will be a depression in the middle of the bandwidth, and this will also lead to a reduction in the performance of the elastic wave device 1. In other embodiments, in order to improve the performance of the elastic wave device 1 well, it is optimal to set the center frequency of the second multimode resonator 40 to 1.05 times the center frequency of the first multimode resonator 30.

[0037] Furthermore, as Figure 2a shown, the first multimode resonator 30 includes a first bus bar 34, a first interdigital transducer structure 33, a first reflector 31, and a second reflector 32 connected in series in sequence. The first reflector 31 and the second reflector 32 are clamped and arranged at both ends of the first interdigital transducer structure 33. The first interdigital transducer structure 33 includes at least three first interdigital transducers. The first bus bar 34, the first interdigital transducer structure 33, the first reflector 31, and the second reflector 32 together constitute the basic structure of a DMS type filter.

[0038] Furthermore, as Figure 2bAs shown, the second multimode resonator 40 includes a second bus bar 44, a second interdigital transducer structure 43, a third reflector 41, and a fourth reflector 42 cascaded in sequence. The third reflector 41 and the fourth reflector 42 are clamped and disposed at both ends of the second interdigital transducer structure 43. The second interdigital transducer structure 43 includes at least three second interdigital transducers. The second bus bar 44, the second interdigital transducer structure 43, the third reflector 41, and the fourth reflector 42 can jointly form the basic structure of a DMS type filter.

[0039] Furthermore, the elastic wave device is a band-pass filter with a bandwidth of 758 MHz - 821 MHz. As can be seen from the above, by connecting the first multimode resonator 30 and the second multimode resonator 40 in parallel and defining the area of the first multimode resonator 30 to be more than 1.6 times that of the second multimode resonator 40, the passband frequency formed by the first multimode resonator 30 and the second multimode resonator 40 can be 758 MHz - 821 MHz, enabling the passband of the elastic wave device 1 of the present application to cover the passbands of Band 28Rx - full band: 758 MHz - 803 MHz and Band 20Rx: 791 MHz - 821 MHz.

[0040] Furthermore, the elastic wave device 1 is a band-pass filter with a bandwidth ratio of 7% or more. The general definition of the bandwidth ratio is: Or it can be expressed as a percentage: In the present application, when the bandwidth is from 758 MHz - 821 MHz, the bandwidth ratio of the elastic wave device 1 is 7% or more. For elastic wave devices in the prior art, their general bandwidth ratio is 2% - 5%. The 7% bandwidth ratio in the present application is equivalent to the wide bandwidth of elastic wave devices in the prior art.

Second Embodiment

[0041] As Figure 7 shown, in this embodiment, an electronic device 100 is provided, which includes, for example, the elastic wave device 1 described in the first embodiment above. The RF block of a mobile phone terminal may include, for example, the electronic device 100 of this embodiment. Specifically, as Figure 7As shown, an elastic wave device 1 and an inductance element 111 are provided on the main surface of the wiring substrate 110; the inductance element is provided to achieve impedance matching on the main surface of the wiring substrate 110, and the inductance element 111 can be, for example, an Integrated Passive Device (IPD). The electronic device 100 can seal the elastic wave device 1 and the inductance element 111 through a sealing portion 112. Among them, external connection terminals 113 are provided on the lower surface of the wiring substrate 110, and the external connection terminals 113 can be mounted on the main printed circuit of a predetermined mobile communication terminal.

[0042] In addition, it can be understood that the foregoing various embodiments are only exemplary descriptions of the present invention. On the premise that the technical features do not conflict, the structures do not contradict, and the invention purpose of the present invention is not violated, the technical solutions of the various embodiments can be arbitrarily combined and used in combination.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An elastic wave device (1), characterized in that, Comprising: An input terminal (10); An output terminal (20); A first multimode resonator (30) connected in series between the input terminal (10) and the output terminal (20); A second multimode resonator (40) connected in series between the input terminal (10) and the output terminal (20) and connected in parallel with the first multimode resonator (30); Wherein, the area of the first multimode resonator (30) is greater than or equal to 1.6 times the area of the second multimode resonator (40), and the center frequency of the first multimode resonator (30) is less than the center frequency of the second multimode resonator (40).

2. The elastic wave device (1) according to claim 1, characterized in that, The area of the first multimode resonator (30) does not exceed 3 times the area of the second multimode resonator (40).

3. The elastic wave device (1) according to claim 1, characterized in that, The elastic wave device (1) further includes a first series resonator (61) and a second series resonator (62); wherein, one end of the first series resonator (61) is connected in series with the input terminal (10), and the other end of the first series resonator (61) is respectively connected in series with the input end of the first multimode resonator (30) and the input end of the second multimode resonator (40); one end of the second series resonator (62) is respectively connected in series with the output end of the first multimode resonator (30) and the output end of the second multimode resonator (40), and the other end of the second series resonator (62) is connected in series with the output terminal (20).

4. The elastic wave device (1) according to claim 3, characterized in that, The elastic wave device (1) further includes a ground terminal (50), a first parallel resonator (63) and a second parallel resonator (64); one end of the first parallel resonator (63) is connected in parallel between the second series resonator (62) and the output terminal (20), and the other end of the first parallel resonator (63) is electrically connected to the ground terminal (50); one end of the second parallel resonator (64) is connected in parallel between the second series resonator (62) and the output terminal (20), and the other end of the second parallel resonator (64) is electrically connected to the ground terminal (50); wherein, the first parallel resonator (63) is connected in parallel with the second parallel resonator (64).

5. The elastic wave device (1) according to claim 4, characterized in that, The first parallel resonator (63) is closer to the first multimode resonator (30) than the second parallel resonator (64), and the area of the first parallel resonator (63) is greater than 1.6 times the area of the second parallel resonator (64).

6. The elastic wave device (1) according to claim 1, characterized in that, The center frequency of the second multimode resonator (40) is 1.04 - 1.06 times the center frequency of the first multimode resonator (30).

7. The elastic wave device (1) according to any one of claims 1-6, characterized in that, The first multimode resonator (30) includes a first bus bar (34), a first interdigital transducer structure (33), a first reflector (31) and a second reflector (32) cascaded in sequence. The first reflector (31) and the second reflector (32) are clamped and arranged at both ends of the first interdigital transducer structure (33), and the first interdigital transducer structure (33) includes at least three first interdigital transducers.

8. The elastic wave device (1) according to claim 7, characterized in that, The second multimode resonator (40) includes a second bus bar (44), a second interdigital transducer structure (43), a third reflector (41), and a fourth reflector (42) cascaded in sequence. The third reflector (41) and the fourth reflector (42) are clamped and disposed at both ends of the second interdigital transducer structure (43). The second interdigital transducer structure (43) includes at least three second interdigital transducers.

9. The elastic wave device (1) according to claim 1, characterized in that: The elastic wave device (1) is a band-pass filter with a bandwidth of 758 MHz - 821 MHz.

10. The elastic wave device (1) according to claim 1, characterized in that: The elastic wave device (1) is a band-pass filter with a bandwidth ratio of 7% or more.

11. An electronic device (100), characterized in that, Comprising: The elastic wave device (1) according to any one of claims 1 - 10 above.

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