CN214799436U - Surface acoustic wave resonator and radio frequency filter - Google Patents

Abstract

The embodiment of the utility model provides a surface acoustic wave syntonizer and radio frequency filter, this surface acoustic wave syntonizer includes: a substrate; a piezoelectric layer on the substrate; the electrode layer is positioned on one side of the piezoelectric layer, which is far away from the substrate; the electrode layer includes an interdigital transducer, and the interdigital transducer includes: a first bus bar and first electrode fingers and first dummy electrode fingers alternately arranged and connected to the first bus bar; a second bus bar and second electrode fingers and second dummy electrode fingers alternately arranged and connected to the second bus bar; the first electrode finger and the second dummy electrode finger are arranged oppositely, a first gap is formed between the first electrode finger and the second dummy electrode finger, the second electrode finger and the first dummy electrode finger are arranged oppositely, and a second gap is formed between the second electrode finger and the first dummy electrode finger. The embodiment of the utility model provides a surface acoustic wave syntonizer and radio frequency filter can make horizontal mode ripple obtain effectual suppression.

Description

Surface acoustic wave resonator and radio frequency filter

Technical Field

The utility model relates to the field of communication, especially, relate to a surface acoustic wave syntonizer and radio frequency filter.

Background

As communication technology advances from 2G to 5G, the number of communication bands increases (from 4 bands of 2G up to more than 50 bands of 5G). In order to improve the compatibility of the smart phone to different communication systems, the filter usage required by the 5G smart phone is remarkably increased, and the large-scale growth of the filter market is promoted. The radio frequency filter widely used in the wireless communication terminal at present is a surface acoustic wave filter, and is responsible for receiving and transmitting radio frequency signals of a channel and outputting signals with specific frequency in various input radio frequency signals. Meanwhile, with the continuous development of mobile communication technology and the modular development of radio frequency front end, the market demand for filters tends to be complicated, high-end and small.

Surface acoustic wave devices based on single crystal piezoelectric lithium tantalate substrates have been widely used in radio frequency filters, are limited by the Q value and high frequency temperature coefficient of single crystal piezoelectric materials, and have been difficult to meet the requirements of radio frequency front-end chips.

Still adopt the surface acoustic wave resonator and the radio frequency filter of traditional design can appear very strong transverse mode ripple in practical application, and the passband clutter is serious, leads to the degradation of whole device performance.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides a surface acoustic wave syntonizer and radio frequency filter can make horizontal mode ripple obtain effectual suppression.

In a first aspect, an embodiment of the present invention provides a surface acoustic wave resonator, which includes: a substrate;

a piezoelectric layer on the substrate;

an electrode layer located on a side of the piezoelectric layer away from the substrate;

the electrode layer includes an interdigital transducer, the interdigital transducer includes: a first bus bar and first electrode fingers and first dummy electrode fingers alternately arranged and connected to the first bus bar; a second bus bar and second electrode fingers and second dummy electrode fingers alternately arranged and connected to the second bus bar; the first electrode finger and the second dummy electrode finger are oppositely arranged, a first gap is formed between the first electrode finger and the second dummy electrode finger, the second electrode finger and the first dummy electrode finger are oppositely arranged, and a second gap is formed between the second electrode finger and the first dummy electrode finger;

the first bus bar includes a first sub-bus bar and a second sub-bus bar, the first sub-bus bar and the second sub-bus bar being connected;

the second bus bar includes a third sub-bus bar and a fourth sub-bus bar, the third sub-bus bar being connected with the fourth sub-bus bar; the first gap includes a first sub-gap and a second sub-gap, the second gap includes a third sub-gap and a fourth sub-gap, the first sub-gap and the third sub-gap are located between the first sub-bus bar and the third sub-bus bar, and the second sub-gap and the fourth sub-gap are located between the second sub-bus bar and the fourth sub-bus bar;

wherein each of the first sub-gaps is arranged along a first direction, each of the third sub-gaps is arranged along the first direction, each of the second sub-gaps is arranged along a second direction, and each of the fourth sub-gaps is arranged along the second direction;

the included angle range between the first direction and the third direction is 2-15 degrees, the included angle range between the second direction and the third direction is 2-15 degrees, and the third direction is perpendicular to the length direction of the first electrode finger in the direction parallel to the plane of the piezoelectric layer.

Optionally, the first sub-bus bar and the third sub-bus bar are parallel, a length direction of the first sub-bus bar is parallel to the first direction, the second sub-bus bar and the fourth sub-bus bar are parallel, and a length direction of the second sub-bus bar is parallel to the second direction.

Optionally, a first electrode finger is disposed between adjacent first gaps, and a second electrode finger is disposed between adjacent second gaps.

Optionally, each of the first electrode finger and the second electrode finger includes a main body and a tip integrally connected to the main body, the tip of the first electrode finger is located on a side of the main body of the first electrode finger away from the first bus bar, and the tip of the second electrode finger is located on a side of the main body of the second electrode finger away from the second bus bar;

the first dummy electrode finger and the second dummy electrode finger both comprise a main body and a tip integrally connected with the main body, the tip of the first dummy electrode finger is positioned on the side, away from the first bus bar, of the main body of the first dummy electrode finger, and the tip of the second dummy electrode finger is positioned on the side, away from the second bus bar, of the main body of the second dummy electrode finger;

in a third direction, the width of the tip is greater than the width of the body.

Optionally, in the third direction, the width of the tip is 1.2 to 1.8 times the width of the main body.

Optionally, the end on the first electrode finger is arranged opposite to the end on the second dummy electrode finger;

the end head on the second electrode finger is arranged opposite to the end head on the first dummy electrode finger.

Optionally, the electrode layer further comprises a reflective gate structure;

the reflective gate structure includes a third bus bar, a fourth bus bar, and a reflective gate; the third bus bar and the fourth bus bar are arranged in parallel;

the first end of the reflecting grid is connected with the third bus bar, and the second end of the reflecting grid is connected with the fourth bus bar;

a reflecting grid structure is arranged on one side, away from the second sub-bus bar, of the first sub-bus bar, and a reflecting grid structure is arranged on one side, away from the first sub-bus bar, of the second sub-bus bar;

the third bus bar is perpendicular to the reflecting grating, and an included angle between the third bus bar and the first direction ranges from 2 degrees to 15 degrees;

or the included angle between the third bus bar and the reflecting grid ranges from 75 degrees to 88 degrees, the length direction of the third bus bar in the reflecting grid structure positioned on one side of the first sub-bus bar far away from the second sub-bus bar is parallel to the first direction, and the length direction of the third bus bar in the reflecting grid structure positioned on one side of the second sub-bus bar far away from the first sub-bus bar is parallel to the second direction.

Optionally, the piezoelectric material of the piezoelectric layer includes a positioning edge, and the positioning edge of the piezoelectric material is parallel to the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger.

Optionally, the surface acoustic wave resonator provided by the embodiment of the present invention further includes an energy trap layer, where the energy trap layer is located between the substrate and the piezoelectric layer;

a first dielectric layer between the energy trap layer and the piezoelectric layer;

and the second dielectric layer is positioned on one side of the electrode layer, which is far away from the piezoelectric layer, and covers the electrode layer.

In a second aspect, an embodiment of the present invention provides a radio frequency filter, which includes the present invention provides an arbitrary embodiment of the surface acoustic wave resonator.

The embodiment of the utility model provides a surface acoustic wave syntonizer through the contained angle that changes first direction and third direction, changes the contained angle of second direction and third direction, realizes the corrugated suppression of horizontal mode of surface acoustic wave syntonizer, and when the contained angle scope of first direction and third direction at 2 ~ 15, the contained angle scope of second direction and third direction is when 2 ~ 15, and horizontal mode ripple just can obtain effectual suppression. The embodiment of the utility model provides a surface acoustic wave syntonizer can make horizontal mode ripple obtain effectual suppression.

Drawings

Fig. 1 is a schematic structural diagram of a surface acoustic wave resonator according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of an interdigital transducer according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of another interdigital transducer provided in the present invention;

fig. 4 is a schematic structural diagram of another interdigital transducer provided in the present invention;

fig. 5 is a schematic structural diagram of another interdigital transducer provided in the present invention;

fig. 6 is a schematic structural diagram of another interdigital transducer provided in the present invention;

fig. 7 is a schematic diagram of an admittance measurement result between a surface acoustic wave resonator in the prior art and a surface acoustic wave resonator provided in an embodiment of the present invention;

fig. 8 is a schematic diagram of an actual measurement result of an admittance real part of a surface acoustic wave resonator provided by an embodiment of the present invention when an included angle between the first direction and the third direction is different;

fig. 9 is a schematic diagram of an actual measurement result of an admittance amplitude of a surface acoustic wave resonator provided by an embodiment of the present invention when an included angle between the first direction and the third direction is different;

fig. 10 is a schematic structural diagram of another interdigital transducer provided in the present invention;

fig. 11 is a schematic top view of an electrode layer according to an embodiment of the present invention;

fig. 12 is a schematic top view of another electrode layer according to an embodiment of the present invention;

fig. 13 is a schematic top view of another electrode layer according to an embodiment of the present invention;

fig. 14 is a schematic top view of another electrode layer according to an embodiment of the present invention;

fig. 15 is a schematic top view of another electrode layer according to an embodiment of the present invention;

fig. 16 is a schematic top view of a surface acoustic wave resonator according to an embodiment of the present invention;

fig. 17 is a schematic diagram of an actual measurement result of insertion loss of an rf filter according to an embodiment of the present invention.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad embodiments of the invention. It should be further noted that, for convenience of description, only some structures, but not all structures, related to the embodiments of the present invention are shown in the drawings.

Fig. 1 is the embodiment of the utility model provides a structural schematic diagram of a surface acoustic wave syntonizer, fig. 2 is the embodiment of the utility model provides a structural schematic diagram of an interdigital transducer, refer to fig. 1 and fig. 2, the utility model provides a surface acoustic wave syntonizer includes: a substrate 110; a piezoelectric layer 120 on the substrate 110; an electrode layer 130, the electrode layer 130 being located on a side of the piezoelectric layer 120 away from the substrate 110; electrode layer 130 includes interdigital transducer 131, and interdigital transducer 131 includes: a first bus bar 10 and first electrode fingers 20 and first dummy electrode fingers 30 alternately arranged and connected to the first bus bar 10; a second bus bar 40 and second electrode fingers 50 and second dummy electrode fingers 60 alternately arranged and connected to the second bus bar 40; the first electrode finger 20 and the second dummy electrode finger 60 are oppositely arranged, a first gap 70 is arranged between the first electrode finger 20 and the second dummy electrode 60, the second electrode finger 50 and the first dummy electrode finger 30 are oppositely arranged, and a second gap 80 is arranged between the second electrode finger 50 and the first dummy electrode 30; the first bus bar 10 includes a first sub-bus bar 11 and a second sub-bus bar 12, the first sub-bus bar 11 and the second sub-bus bar 12 being connected; the second bus bar 40 includes a third sub-bus bar 41 and a fourth sub-bus bar 42, the third sub-bus bar 41 being connected with the fourth sub-bus bar 42; the first gap 70 includes a first sub-gap 71 and a second sub-gap 72, the second gap 80 includes a third sub-gap 81 and a fourth sub-gap 82, the first sub-gap 71 and the third sub-gap 81 are located between the first sub-bus bar 11 and the third sub-bus bar 41, and the second sub-gap 72 and the fourth sub-gap 82 are located between the second sub-bus bar 12 and the fourth sub-bus bar 42; wherein each first sub-gap 71 is arranged along the first direction x, each third sub-gap 81 is arranged along the first direction x, each second sub-gap 72 is arranged along the second direction y, and each fourth sub-gap 82 is arranged along the second direction y; the angle beta between the first direction x and the third direction z is in the range of 2 to 15 deg., the angle theta between the second direction y and the third direction z is in the range of 2 to 15 deg., and the third direction z is perpendicular to the length direction of the first electrode fingers 20 in the direction parallel to the plane of the piezoelectric layer.

Specifically, the material of the substrate 110 may be high-resistivity silicon, which may be P-type high-resistivity silicon or N-type high-resistivity silicon, and the resistivity of the high-resistivity silicon is greater than 2000 Ω · cm, and preferably, the resistivity of the high-resistivity silicon is greater than 10000 Ω · cm. The piezoelectric layer 120 may be made of lithium tantalate or lithium niobate, wherein a cutting angle of lithium tantalate may be 30-50 °, a thickness of the piezoelectric layer 120 may be 300-1000 nm, and the electrode layer 130 is formed by depositing a metal film on the surface of the piezoelectric layer 120 by electron beam evaporation, plasma, magnetron sputtering, or the like, wherein the material of the deposited metal film may be titanium, chromium, copper, silver, aluminum, or the like, or a combination thereof. The number of the first electrode fingers 20, the number of the first dummy electrode fingers 30, the number of the second electrode fingers 50, and the number of the second dummy electrode fingers 60 are all equal, the first electrode fingers 20 and the first dummy electrode fingers 30 are alternately connected to the first sub-bus 11, the first electrode fingers 20 and the first dummy electrode fingers 30 are alternately connected to the second sub-bus 12, the second electrode fingers 50 and the second dummy electrode fingers 60 are alternately connected to the third sub-bus 41, and the second electrode fingers 50 and the second dummy electrode fingers 60 are alternately connected to the fourth sub-bus 42. The first sub-gap 71 is located between the first dummy electrode finger 30 connected to the first sub-bus bar 11 and the second electrode finger 50 connected to the third sub-bus bar 41, the third sub-gap 81 is located between the first electrode finger 20 connected to the first sub-bus bar 11 and the second dummy electrode finger 60 connected to the third sub-bus bar 41, the second sub-gap 72 is located between the first dummy electrode finger 30 connected to the second sub-bus bar 12 and the second electrode finger 50 connected to the fourth sub-bus bar 42, and the fourth sub-gap 82 is located between the first electrode finger 20 connected to the second sub-bus bar 12 and the second dummy electrode finger 60 connected to the fourth sub-bus bar 42. The arrangement direction of the first sub-gaps 71 is parallel to the arrangement direction of the third sub-gaps 81, the first sub-gaps 71 are arranged along the first direction x, the included angle beta between the first direction x and the third direction z is larger than 2 degrees and smaller than 15 degrees, the arrangement direction of the second sub-gaps 72 is parallel to the arrangement direction of the fourth sub-gaps 82, the second sub-gaps 72 are arranged along the second direction y, and the included angle theta between the second direction y and the third direction z is larger than 2 degrees and smaller than 15 degrees. Fig. 3 is a schematic structural diagram of another interdigital transducer provided in the embodiment of the present invention, and referring to fig. 3, the arrangement direction of the first sub-gap 71 and the arrangement direction of the third sub-gap 81 may be parallel to the second direction y, and the arrangement direction of the second sub-gap 72 and the arrangement direction of the fourth sub-gap 82 may be parallel to the first direction x. The number of the first electrode fingers 20 connected to the first sub-bus bar 11 and the number of the second sub-bus bar 12 connected to the first electrode fingers 20 may be equal or unequal, fig. 4 is a schematic structural diagram of another interdigital transducer provided in the embodiment of the present invention, referring to fig. 4, the number of the first electrode fingers 20 connected to the first sub-bus bar 11 is greater than the number of the second sub-bus bar 12 connected to the first electrode fingers 20, fig. 5 is a schematic structural diagram of another interdigital transducer provided in the embodiment of the present invention, referring to fig. 5, the number of the first electrode fingers 20 connected to the first sub-bus bar 11 is less than the number of the second sub-bus bar 12 connected to the first electrode fingers 20. An included angle β between the first direction x and the third direction z and an included angle θ between the second direction y and the third direction z may be equal to or unequal to each other, fig. 6 is a schematic structural diagram of another interdigital transducer provided in the embodiment of the present invention, and referring to fig. 6, the included angle β between the first direction x and the third direction z is smaller than the included angle θ between the second direction y and the third direction z. Fig. 7 is a schematic diagram of the measured result of the admittance of the surface acoustic wave resonator in the prior art and the surface acoustic wave resonator provided by the embodiment of the present invention, referring to fig. 7, where a dotted line 21 in fig. 7 represents the relationship between the amplitude and the frequency of the admittance of the surface acoustic wave resonator in the prior art, a dotted line 22 in fig. 7 represents the relationship between the real part of the admittance and the frequency of the surface acoustic wave resonator in the prior art, a solid line 23 in fig. 7 represents the relationship between the amplitude and the frequency of the admittance of the surface acoustic wave resonator provided by the embodiment of the present invention, a solid line 24 in fig. 7 represents the relationship between the real part of the admittance and the frequency of the surface acoustic wave resonator provided by the embodiment of the present invention, and it is apparent from fig. 7 that the transverse mode ripple appears in the relationship between the real part of the admittance and the frequency of the surface acoustic wave resonator in the prior art, where the transverse mode ripple includes a ripple 1-a6, in practical application, the generated transverse mode ripples are not suitable for the generation of the rf filter, and the transverse mode ripples a1-a6 appearing in the dotted line 22 in fig. 7 do not appear in the solid line 24 in fig. 7, which shows that the surface acoustic wave resonator provided by the embodiment of the present invention can effectively suppress the transverse ripples. Fig. 8 is a schematic diagram of an actual measurement result of an admittance real part of a surface acoustic wave resonator provided by an embodiment of the present invention when an included angle between the first direction and the third direction is different, fig. 9 is a schematic diagram of an actual measurement result of an admittance amplitude of a surface acoustic wave resonator provided by an embodiment of the present invention when an included angle between the first direction and the third direction is different, referring to fig. 8 and 9, a certain dB value is added to a vertical coordinate, so that the schematic diagram of an actual measurement result looks more intuitive, when an included angle between the first direction and the third direction is 0 °, an included angle between the second direction and the third direction is equal to an included angle between the first direction and the third direction, a serious transverse mode ripple appears on the surface acoustic wave resonator, when an included angle between the first direction and the third direction is 3 °, 5 °, 7 ° and 11 °, an included angle between the second direction and the third direction is equal to an included angle between the first direction and the third direction, the transverse mode ripples can be effectively inhibited, and preferably, the included angle between the first direction and the third direction is more than 3 degrees, so that the inhibiting effect of the transverse mode ripples is more obvious. It should be noted that, when the angle between the first direction and the third direction changes and the angle between the second direction and the third direction changes, the lengths, widths, and directions of the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger do not change.

The embodiment of the utility model provides a surface acoustic wave syntonizer through the contained angle that changes first direction and third direction, changes the contained angle of second direction and third direction, realizes the corrugated suppression of horizontal mode of surface acoustic wave syntonizer, and when the contained angle scope of first direction and third direction at 2 ~ 15, the contained angle scope of second direction and third direction is when 2 ~ 15, and horizontal mode ripple just can obtain effectual suppression. The embodiment of the utility model provides a surface acoustic wave syntonizer can make horizontal mode ripple obtain effectual suppression.

Alternatively, with continued reference to fig. 2, the first sub-bus bar 11 and the third sub-bus bar 41 are parallel, the length direction of the first sub-bus bar 11 is parallel to the first direction x, the second sub-bus bar 12 is parallel to the fourth sub-bus bar 42, and the length direction of the second sub-bus bar 12 is parallel to the second direction y.

Specifically, the arrangement direction of the first sub-gap 71 is parallel to the longitudinal direction of the first sub-bus bar 11, the arrangement direction of the third sub-gap 81 is parallel to the longitudinal direction of the third sub-bus bar 41, the arrangement direction of the second sub-gap 72 is parallel to the longitudinal direction of the second sub-bus bar 12, and the arrangement direction of the fourth sub-gap 82 is parallel to the longitudinal direction of the fourth sub-bus bar 42. It should be noted that the direction of the line connecting the aperture center points of the first electrode fingers 20 connected to the first sub bus bar 11 is parallel to the first direction x, the direction of the line connecting the aperture center points of the second electrode fingers 50 connected to the third sub bus bar 41 is parallel to the first direction x, the direction of the line connecting the aperture center points of the first electrode fingers 20 connected to the second sub bus bar 12 is parallel to the second direction y, and the direction of the line connecting the aperture center points of the second electrode fingers 50 connected to the fourth sub bus bar 42 is parallel to the second direction y.

Optionally, with continued reference to fig. 2, a first electrode finger 20 is disposed between adjacent first gaps 70 and a second electrode finger 50 is disposed between adjacent second gaps 80.

Specifically, the first gap 70 includes a first sub-gap 71 and a second sub-gap 72, a first electrode finger 20 is disposed between the first gap 70, the first electrode finger 20 may be disposed between the first sub-gap 71 and the first sub-gap 71, the first electrode finger 20 may be disposed between the second sub-gap 72 and the second sub-gap 72, or the first electrode finger 20 may be disposed between the first sub-gap 71 and the second sub-gap 72. The second gap 80 includes a third sub-gap 81 and a fourth sub-gap 82, a second electrode finger 50 is disposed between the second gap 80, a second electrode finger 50 may be disposed between the third sub-gap 81 and the third sub-gap 81, a second electrode finger 50 may be disposed between the fourth sub-gap 82 and the fourth sub-gap 82, or a second electrode finger 50 may be disposed between the third sub-gap 81 and the fourth sub-gap 82.

Alternatively, fig. 10 is a schematic structural diagram of another interdigital transducer provided in an embodiment of the present invention, referring to fig. 10, each of the first electrode finger 20 and the second electrode finger 50 includes a main body 11 and a terminal 12 integrally connected to the main body 11, the terminal 12 of the first electrode finger 20 is located on a side of the main body 11 of the first electrode finger 20 away from the first bus bar 10, and the terminal 12 of the second electrode finger 50 is located on a side of the main body 11 of the second electrode finger 50 away from the second bus bar 40; each of the first dummy electrode finger 30 and the second dummy electrode finger 60 includes a main body 11 and a tip 12 integrally connected to the main body 11, the tip 12 of the first dummy electrode finger 30 is located on a side of the main body 11 of the first dummy electrode finger 30 away from the first bus bar 10, and the tip 12 of the second dummy electrode finger 60 is located on a side of the main body 11 of the second dummy electrode finger 60 away from the second bus bar 40; in the third direction z, the width of the tip 12 is greater than the width of the body 11.

Specifically, the propagation direction of the surface acoustic wave is parallel to the third direction z, and the width of the end 12 is larger than that of the body 11, so that the end 12 can block transverse energy leakage in the surface acoustic wave, noise waves in the surface acoustic wave are suppressed, and the Q value of the surface acoustic wave resonator is improved. It should be noted that fig. 10 illustrates the shape of the tip 12 as a rectangle, and the tip 12 may be a triangle or a polygon.

Optionally, in the third direction, the width of the tip is 1.2 to 1.8 times the width of the main body.

Specifically, the width of the end is set to be 1.2-1.8 times of the width of the main body, and the length of the end in the length direction of the first electrode finger is set to be 0.3-0.7 times of the wavelength of the interdigital transducer, so that the end can further block transverse energy leakage in the surface acoustic wave, clutter in the surface acoustic wave is better suppressed, and the Q value of the surface acoustic wave resonator is further improved.

Optionally, with continued reference to fig. 10, the tip 12 on the first electrode finger 20 is disposed opposite the tip 12 on the second dummy electrode finger 60; the tips 12 of the second electrode fingers 50 are disposed opposite the tips 12 of the first dummy electrode fingers 30.

Specifically, the end 12 on the first electrode finger 20 and the end 12 on the second dummy electrode finger 60 are arranged oppositely, and the end 12 on the second electrode finger 50 and the end 12 on the first dummy electrode finger 30 are arranged oppositely, so that the end 12 can further block the transverse energy leakage in the surface acoustic wave, the clutter in the surface acoustic wave can be better suppressed, and the Q value of the surface acoustic wave resonator can be further improved.

Optionally, in the length direction of the first electrode finger, the length of the first dummy electrode finger is 0.5-1.5 times of the wavelength of the interdigital transducer; the aperture of the interdigital transducer is 9-40 times of the wavelength of the interdigital transducer.

Specifically, the length of the first dummy electrode finger is set to be 0.5-1.5 times of the wavelength of the interdigital transducer, and the aperture of the interdigital transducer is set to be 9-40 times of the wavelength of the interdigital transducer, so that the Q value of the surface acoustic wave resonator can be further improved more obviously.

Optionally, fig. 11 is a schematic diagram of a top-view structure of an electrode layer according to an embodiment of the present invention, fig. 12 is a schematic diagram of a top-view structure of another electrode layer according to an embodiment of the present invention, referring to fig. 11 and 12, the electrode layer further includes a reflective grid structure 132; the reflective fence structure 132 includes a third bus bar 90, a fourth bus bar 91, and a reflective fence 92; the third bus bar 90 and the fourth bus bar 91 are arranged in parallel; a first end of the reflection fence 92 is connected to the third bus bar 90, and a second end of the reflection fence 92 is connected to the fourth bus bar 91; a reflecting grid structure 132 is arranged on the side of the first sub-bus bar 11 far away from the second sub-bus bar 12, and a reflecting grid structure 132 is arranged on the side of the second sub-bus bar 12 far away from the first sub-bus bar 11; wherein the third bus bar 90 is perpendicular to the reflective grid 92, and an included angle between the third bus bar 90 and the first direction x is 2-15 °; or the included angle between the third bus bar 90 and the reflective grid 92 ranges from 75 ° to 88 °, and the length direction of the third bus bar 90 in the reflective grid structure 132 on the side of the first sub-bus bar 11 away from the second sub-bus bar 12 is parallel to the first direction x, and the length direction of the third bus bar 90 in the reflective grid structure 132 on the side of the second sub-bus bar 12 away from the first sub-bus bar 11 is parallel to the second direction y.

Specifically, the reflective grating 92 in the reflective grating structure 132 in fig. 11 is perpendicular to the third bus bar 90, and an included angle between the reflective grating 92 and the third bus bar 90 in the reflective grating structure 132 in fig. 12 ranges from 75 ° to 88 °. Referring to fig. 11, when the first direction x and the third direction z form an angle β, the third bus bar 90 also forms an angle β with the first direction x. Referring to fig. 12, when the first direction x and the third direction z form an angle β, the third bus bar 90 is parallel to the first direction x, and the reflective grid 92 forms an angle of 90 ° - β with the third bus bar 90. Fig. 13 is a schematic top view of another electrode layer according to an embodiment of the present invention, referring to fig. 13, when an included angle between the second direction y and the third direction z is θ, an included angle between the third bus bar 90 and the second direction y is also θ. Fig. 14 is a schematic top view of another electrode layer according to an embodiment of the present invention, referring to fig. 14, a length direction of the third bus bar 90 in the reflective grid structure 132 on a side of the first sub-bus bar 11 away from the second sub-bus bar 12 is parallel to the second direction y, and a length direction of the third bus bar 90 in the reflective grid structure 132 on a side of the second sub-bus bar 12 away from the first sub-bus bar 11 is parallel to the first direction x. Fig. 15 is a schematic top view of another electrode layer according to an embodiment of the present invention, and referring to fig. 15, an interdigital transducer 131 in an electrode layer according to an embodiment of the present invention may be formed by serially connecting a plurality of interdigital transducers 131, and a reflective grating structure 132 is located on both sides of the serially connected interdigital transducer 131. The reflection bars structure 132 can reflect the energy of surface acoustic wave, concentrates the energy in the interdigital transducer, the embodiment of the utility model provides an in set up all the time that reflection bars 92 and first electrode indicate, the second electrode indicates, first dummy electrode indicates and second dummy electrode indicates to be parallel, further guarantee that reflection bars structure 132 concentrates the energy of the surface acoustic wave of reflection in the interdigital transducer, further improve the Q value of surface acoustic wave syntonizer. Wherein, the number of the reflective gratings 92 in each reflective grating structure 132 is 15-30. It should be noted that, the interdigital transducer in the schematic top view structure of the electrode layer provided in the embodiments of the present invention includes a terminal integrally connected to the main body, and the interdigital transducer in the electrode layer may not include a terminal integrally connected to the main body. Optionally, fig. 16 is a schematic diagram of a top view structure of a surface acoustic wave resonator according to an embodiment of the present invention, referring to fig. 16, the piezoelectric material of the piezoelectric layer 120 includes a positioning edge 121, and the positioning edge 121 of the piezoelectric material is parallel to the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger.

Specifically, a positioning edge 121 is arranged in the piezoelectric material, and a first electrode finger, a second electrode finger, a first dummy electrode finger and a second dummy electrode finger in each interdigital transducer are all parallel to the positioning edge 121, so that each interdigital transducer in the electrode layer can be arranged in parallel, and because the propagation direction of the surface acoustic wave is perpendicular to the positioning edge 121, each first electrode finger, each second electrode finger, each first dummy electrode finger and each second dummy electrode finger in the interdigital transducer can block transverse energy leakage in the surface acoustic wave, thereby better inhibiting clutter in the surface acoustic wave and further improving the Q value of the surface acoustic wave resonator.

Optionally, with continuing reference to fig. 1, the surface acoustic wave resonator provided in the embodiment of the present invention further includes an energy trap layer 140, where the energy trap layer 140 is located between the substrate 110 and the piezoelectric layer 120; a first dielectric layer 150, the first dielectric layer 150 being located between the energy trap layer 140 and the piezoelectric layer 120; and a second dielectric layer 160, wherein the second dielectric layer 160 is located on the side of the electrode layer 130 away from the piezoelectric layer 120 and covers the electrode layer 130.

Specifically, a layer of energy trap layer 140 is prepared on the substrate 110, the material of the energy trap layer 140 may be polysilicon, and the setting of the energy trap layer 140 may reduce the accumulation of charges, thereby further improving the Q value of the surface acoustic wave resonator. A layer of low-sound-velocity silicon dioxide is grown on the side, away from the substrate 110, of the energy trap layer 140 in a plasma enhanced chemical vapor deposition manner or a silicon thermal oxidation manner, so that the first dielectric layer 150 is formed, chemical mechanical planarization is adopted, the thickness value of the first dielectric layer 150 is finally controlled within the range of 300-800 nm, and the temperature drift coefficient of the first dielectric layer 150 can be further improved. The second dielectric layer 160 serves as a passivation layer and a frequency modulation layer of the saw surface wave resonator, the material of the second dielectric layer 160 may be silicon dioxide or silicon nitride, and the second dielectric layer 160 covers the electrode layer 130. Substrate 110, energy trap layer 140 and first dielectric layer 150 constitute compound multilayer substrate, the embodiment of the utility model provides a compound multilayer substrate can make surface acoustic wave resonator and radio frequency filter realize characteristics such as low insertion loss, pass band smoothness, high Q value and outstanding low frequency temperature.

An embodiment of the utility model provides a radio frequency filter, this radio frequency filter includes the utility model discloses arbitrary embodiment provides a surface acoustic wave syntonizer.

Figure 17 is radio frequency filter among the prior art and the embodiment of the utility model provides a radio frequency wave filter's insertion loss's actual measurement result schematic diagram, refer to figure 17, the dotted line in figure 17 represents radio frequency filter's insertion loss and frequency's relation schematic diagram among the prior art, and the solid line in figure 17 represents the utility model provides a radio frequency filter's insertion loss and frequency's relation schematic diagram can be seen from figure 17, and the insertion loss that radio frequency filter appears among the prior art is unstable and the passband clutter is serious, will lead to the worsening of whole device performance, and the utility model provides a clutter does not appear in the radio frequency filter passband, and is visible, the utility model provides a radio frequency filter can make the passband more level and smooth.

The embodiment of the utility model provides a radio frequency filter with the utility model discloses the surface acoustic wave syntonizer that arbitrary embodiment provided has corresponding beneficial effect, does not in the detailed technical details of this embodiment, and is detailed the utility model discloses the surface acoustic wave syntonizer that arbitrary embodiment provided.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the embodiments of the present invention are not limited to the particular embodiments described herein, but are capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the embodiments of the invention. Therefore, although the embodiments of the present invention have been described in greater detail through the above embodiments, the embodiments of the present invention are not limited to the above embodiments, and many other equivalent embodiments can be included without departing from the concept of the embodiments of the present invention, and the scope of the embodiments of the present invention is determined by the scope of the appended claims.

Claims (10)

1. A surface acoustic wave resonator, comprising:

a substrate;

a piezoelectric layer on the substrate;

an electrode layer located on a side of the piezoelectric layer away from the substrate;

the electrode layer includes an interdigital transducer, the interdigital transducer includes: a first bus bar and first electrode fingers and first dummy electrode fingers alternately arranged and connected to the first bus bar; a second bus bar and second electrode fingers and second dummy electrode fingers alternately arranged and connected to the second bus bar; the first electrode finger and the second dummy electrode finger are oppositely arranged, a first gap is formed between the first electrode finger and the second dummy electrode finger, the second electrode finger and the first dummy electrode finger are oppositely arranged, and a second gap is formed between the second electrode finger and the first dummy electrode finger;

the first bus bar includes a first sub-bus bar and a second sub-bus bar, the first sub-bus bar and the second sub-bus bar being connected;

the second bus bar includes a third sub-bus bar and a fourth sub-bus bar, the third sub-bus bar being connected with the fourth sub-bus bar; the first gap includes a first sub-gap and a second sub-gap, the second gap includes a third sub-gap and a fourth sub-gap, the first sub-gap and the third sub-gap are located between the first sub-bus bar and the third sub-bus bar, and the second sub-gap and the fourth sub-gap are located between the second sub-bus bar and the fourth sub-bus bar;

wherein each of the first sub-gaps is arranged along a first direction, each of the third sub-gaps is arranged along the first direction, each of the second sub-gaps is arranged along a second direction, and each of the fourth sub-gaps is arranged along the second direction;

the included angle range between the first direction and the third direction is 2-15 degrees, the included angle range between the second direction and the third direction is 2-15 degrees, and the third direction is perpendicular to the length direction of the first electrode finger in the direction parallel to the plane of the piezoelectric layer.

2. A surface acoustic wave resonator according to claim 1,

the first sub-bus bar and the third sub-bus bar are parallel, a length direction of the first sub-bus bar is parallel to the first direction, the second sub-bus bar and the fourth sub-bus bar are parallel, and a length direction of the second sub-bus bar is parallel to the second direction.

3. A surface acoustic wave resonator according to claim 1, wherein a first electrode finger is provided between adjacent ones of said first gaps, and a second electrode finger is provided between adjacent ones of said second gaps.

4. The surface acoustic wave resonator according to claim 1, wherein each of the first electrode finger and the second electrode finger includes a body and a tip integrally connected to the body, the tip of the first electrode finger being located on a side of the body of the first electrode finger away from the first bus bar, and the tip of the second electrode finger being located on a side of the body of the second electrode finger away from the second bus bar;

the first dummy electrode finger and the second dummy electrode finger both comprise a main body and a tip integrally connected with the main body, the tip of the first dummy electrode finger is positioned on the side, away from the first bus bar, of the main body of the first dummy electrode finger, and the tip of the second dummy electrode finger is positioned on the side, away from the second bus bar, of the main body of the second dummy electrode finger;

in a third direction, the width of the tip is greater than the width of the body.

5. A surface acoustic wave resonator according to claim 4, wherein the width of the tip in the third direction is 1.2 times to 1.8 times the width of the body.

6. The resonator of claim 2, wherein the termination on the first electrode finger is disposed opposite the termination on the second dummy electrode finger;

the end head on the second electrode finger is arranged opposite to the end head on the first dummy electrode finger.

7. A surface acoustic wave resonator according to claim 1, wherein said electrode layer further includes a reflective gate structure;

the reflective gate structure includes a third bus bar, a fourth bus bar, and a reflective gate; the third bus bar and the fourth bus bar are arranged in parallel;

the first end of the reflecting grid is connected with the third bus bar, and the second end of the reflecting grid is connected with the fourth bus bar;

a reflecting grid structure is arranged on one side, away from the second sub-bus bar, of the first sub-bus bar, and a reflecting grid structure is arranged on one side, away from the first sub-bus bar, of the second sub-bus bar;

the third bus bar is perpendicular to the reflecting grating, and an included angle between the third bus bar and the first direction ranges from 2 degrees to 15 degrees;

or the included angle between the third bus bar and the reflecting grid ranges from 75 degrees to 88 degrees, the length direction of the third bus bar in the reflecting grid structure positioned on one side of the first sub-bus bar far away from the second sub-bus bar is parallel to the first direction, and the length direction of the third bus bar in the reflecting grid structure positioned on one side of the second sub-bus bar far away from the first sub-bus bar is parallel to the second direction.

8. The surface acoustic wave resonator according to claim 1, wherein the piezoelectric material of the piezoelectric layer includes a positioning edge, and the positioning edge of the piezoelectric material is parallel to the first electrode finger, the second electrode finger, the first dummy electrode finger, and the second dummy electrode finger.

9. The surface acoustic wave resonator according to claim 1, further comprising an energy trap layer between the substrate and the piezoelectric layer;

a first dielectric layer between the energy trap layer and the piezoelectric layer;

and the second dielectric layer is positioned on one side of the electrode layer, which is far away from the piezoelectric layer, and covers the electrode layer.

10. A radio frequency filter comprising the surface acoustic wave resonator according to any one of claims 1 to 9.

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