WO2015080278A1 - 弾性波素子、分波器および通信装置 - Google Patents
弾性波素子、分波器および通信装置 Download PDFInfo
- Publication number
- WO2015080278A1 WO2015080278A1 PCT/JP2014/081662 JP2014081662W WO2015080278A1 WO 2015080278 A1 WO2015080278 A1 WO 2015080278A1 JP 2014081662 W JP2014081662 W JP 2014081662W WO 2015080278 A1 WO2015080278 A1 WO 2015080278A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- electrode
- electrode finger
- reflector
- main region
- center
- Prior art date
Links
Images
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/87—Electrodes or interconnections, e.g. leads or terminals
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
- H03H9/14517—Means for weighting
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/25—Constructional features of resonators using surface acoustic waves
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
- H03H9/72—Networks using surface acoustic waves
- H03H9/725—Duplexers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/0004—Impedance-matching networks
- H03H9/0009—Impedance-matching networks using surface acoustic wave devices
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/0023—Balance-unbalance or balance-balance networks
- H03H9/0028—Balance-unbalance or balance-balance networks using surface acoustic wave devices
- H03H9/0033—Balance-unbalance or balance-balance networks using surface acoustic wave devices having one acoustic track only
- H03H9/0038—Balance-unbalance or balance-balance networks using surface acoustic wave devices having one acoustic track only the balanced terminals being on the same side of the track
Definitions
- the present invention relates to an acoustic wave element, a duplexer, and a communication device.
- an acoustic wave element is used as a duplexer for filtering a signal transmitted / received from an antenna.
- the acoustic wave element includes a piezoelectric substrate and excitation electrodes formed on the main surface of the piezoelectric substrate.
- the acoustic wave element utilizes a characteristic capable of mutually converting an electric signal and a surface acoustic wave by the relationship between the excitation electrode and the piezoelectric substrate.
- the duplexer uses, for example, a plurality of acoustic wave elements to configure a reception filter (Rx filter) or a transmission filter (see JP 2007-214902 A).
- a reception band or a transmission band is set by combining a plurality of acoustic wave elements.
- one of the problems is to improve the characteristics in the pass band of the reception band or the transmission band.
- the present invention has been made in view of such circumstances, and an object thereof is to provide an elastic wave element, a duplexer, and a communication device that can improve characteristics in a signal pass band. is there.
- An elastic wave device includes a piezoelectric substrate, an excitation electrode, and a reflector.
- the excitation electrode is located on the upper surface of the piezoelectric substrate and has a plurality of electrode fingers, and generates an elastic wave.
- the reflector is located on the upper surface of the piezoelectric substrate and has a plurality of reflector electrode fingers. Two reflectors are arranged so as to sandwich the excitation electrode in the propagation direction of the elastic wave.
- the excitation electrode is located between both ends in the propagation direction of the elastic wave, and a main region where the electrode finger design of the electrode finger is uniform, and the main region is from a region where the electrode finger design is modulated to an end portion. And two end regions located on both sides of the main region.
- the resonance frequency determined by the electrode finger design of the reflector electrode finger is lower than the resonance frequency determined by the electrode finger design of the electrode finger in the main region of the excitation electrode.
- the distance between the center of the electrode finger and the center of the electrode finger adjacent thereto is a
- the number of the electrode fingers constituting the end region is m
- the electrode in the main region The center of the electrode finger located closest to the end region of the finger and the center of the reflector electrode finger located closest to the end region of the reflector electrode finger of the reflector When the distance is x, 0.5 ⁇ a ⁇ (m + 1) ⁇ x ⁇ a ⁇ (m + 1) is satisfied.
- a duplexer includes an antenna terminal, a transmission filter that filters a transmission signal and outputs the filtered signal to the antenna terminal, and a reception filter that filters a reception signal from the antenna terminal. It is a waver, Comprising: The said transmission filter or the said reception filter has the above-mentioned elastic wave element.
- a communication apparatus includes an antenna, the above-described duplexer electrically connected to the antenna, and an RF-IC electrically connected to the duplexer.
- the duplexer According to the acoustic wave device, the duplexer, and the communication device of the present invention, it is possible to improve the characteristics in the signal pass band.
- FIG. 2 is an enlarged plan view in which a part of an IDT electrode is enlarged in the acoustic wave device of FIG. 1.
- FIG. 2 is an enlarged plan view in which a part of a reflector is enlarged in the acoustic wave device of FIG. 1.
- FIG. 2 is an enlarged plan view in which a part of an IDT electrode is enlarged in the acoustic wave device of FIG. 1.
- FIG. 5 schematically shows the relationship between the phase of the repeated array portion in the main region and the end region of the acoustic wave resonance. It is the result of having simulated the elastic wave element concerning comparative example 1, and (b) expands a part of (a). It is the result of having simulated the elastic wave element concerning Example 1.
- FIG. It is the result of having simulated the elastic wave element concerning Example 1.
- FIG. It is the result of having simulated the elastic wave element concerning the comparative example 2, (b) expands a part of (a).
- the elastic wave element concerning Example 1 it is the result of having simulated the position range of the change part which has an effect.
- FIG. 2 It is a top view which shows the modification (Example 2) of the elastic wave element which concerns on one Embodiment of this invention. It is the result of having simulated the elastic wave element which concerns on Example 2.
- FIG. It is the result of having simulated the range of the change part which has an effect in the elastic wave element concerning Example 2.
- FIG. It is the schematic explaining the communication apparatus which concerns on one Embodiment of this invention.
- It is a circuit diagram explaining the duplexer concerning one embodiment of the present invention. It is the result of having simulated the duplexer of FIG. It is a principal part enlarged view which shows a part of IDT electrode and reflector electrode of the elastic wave element of FIG. It is the result of having simulated the elastic wave element concerning Example 3, and (b) expands a part of (a).
- the elastic wave element may be either upward or downward, but in the following, for convenience, the orthogonal coordinate system xyz is defined and the upper side and the lower side are defined with the positive side in the z direction as the upper side.
- FIG. 1 is a plan view showing a configuration of an acoustic wave (SAW) device 1 according to an embodiment of the present invention.
- FIG. 2 is a partial cross-sectional view taken along the line Ic-Ic in FIG.
- the SAW element 1 includes a piezoelectric substrate 2, an excitation electrode (IDT (Interdigital Transducer) electrode) 3 and a reflector 4 provided on the upper surface 2 ⁇ / b> A of the piezoelectric substrate 2.
- IDT Interdigital Transducer
- the SAW element 1 can improve the characteristics of the signal pass band by the electrode finger design of the two end regions 3b located on the reflector 4 side of the IDT electrode 3 and the electrode finger design of the reflector 4. it can.
- each component requirement is explained in full detail.
- the piezoelectric substrate 2 is composed of a single crystal substrate having piezoelectricity made of lithium niobate (LiNbO 3 ) crystal or lithium tantalate (LiTaO 3 ) crystal.
- the piezoelectric substrate 2 is composed of a 36 ° to 48 ° YX cut LiTaO 3 substrate.
- the planar shape and various dimensions of the piezoelectric substrate 2 may be set as appropriate.
- the thickness (z direction) of the piezoelectric substrate 2 is 0.2 mm to 0.5 mm.
- the IDT electrode 3 includes a first comb electrode 30a and a second comb electrode 30b as shown in FIG.
- the first comb-teeth electrode 30a and the second comb-teeth electrode 30b are simply referred to as the comb-teeth electrode 30 and may not be distinguished from each other.
- the comb electrode 30 has two bus bars 31 facing each other and a plurality of electrode fingers 32 extending from each bus bar 31 to the other bus bar 31 side.
- the pair of comb-shaped electrodes 30 are arranged so that the first electrode fingers 32a and the second electrode fingers 32b mesh with each other in the elastic wave propagation direction.
- a dummy electrode facing the electrode finger 32 may be disposed on the bus bar 31. This embodiment is a case where no dummy electrode is arranged.
- Elastic waves are generated and propagated in a direction orthogonal to the plurality of electrode fingers 32. Accordingly, in consideration of the crystal orientation of the piezoelectric substrate 2, the two bus bars 31 are arranged so as to face each other in a direction intersecting the direction in which the elastic wave is desired to propagate.
- the plurality of electrode fingers 32 are formed to extend in a direction orthogonal to the direction in which the elastic wave is desired to propagate.
- the propagation direction of the elastic wave is determined by the orientation of the plurality of electrode fingers 32, but in the present embodiment, for convenience, the orientation of the plurality of electrode fingers 32 will be described with reference to the propagation direction of the elastic wave. There is.
- the bus bar 31 is, for example, formed in a long shape extending linearly with a substantially constant width. Accordingly, the edges of the bus bars 31 facing each other are linear.
- the plurality of electrode fingers 32 are formed in an elongated shape extending in a straight line with a substantially constant width, and are arranged at substantially constant intervals in the propagation direction of the elastic wave.
- a main region 3a disposed between both ends and two end regions 3b from both ends to the main region 3a are set in the elastic wave propagation direction.
- the plurality of electrode fingers 32 of the pair of comb electrodes 30 constituting the main region 3a of the IDT electrode 3 are set such that the distance between the centers of the widths of the adjacent electrode fingers 32 is the first pitch Pt1a.
- the first pitch Pt1a is set in the main region 3a to be equal to, for example, a half wavelength of the wavelength ⁇ of the elastic wave at the frequency to be resonated.
- the wavelength ⁇ (2 ⁇ Pt1a) is, for example, 1.5 ⁇ m to 6 ⁇ m.
- the first pitch Pt1a is equal to the width of the second electrode finger 32b adjacent to the first electrode finger 32a from the center of the width of the first electrode finger 32a in the elastic wave propagation direction. It refers to the distance to the center.
- the center of the width of the electrode finger 32 may be simply referred to as “the center of the electrode finger 32”.
- Each electrode finger 32 has a width w1 in the propagation direction of the elastic wave appropriately set according to electrical characteristics required for the SAW element 1 and the like.
- the width w1 of the electrode finger 32 is, for example, 0.3 to 0.7 times the first pitch Pt1a.
- the length of the plurality of electrode fingers 32 (the length from the bus bar 31 to the tip) is set to, for example, approximately the same length.
- the length of each electrode finger 32 may be changed, for example, it may be lengthened or shortened as it proceeds in the propagation direction of the elastic wave.
- the apodized IDT electrode 3 may be configured by changing the length of each electrode finger 32 with respect to the propagation direction. In this case, it is possible to reduce the spurious in the transverse mode and improve the power durability.
- the IDT electrode 3 is composed of a conductive layer 15 made of metal, for example.
- the metal include Al or an alloy containing Al as a main component (Al alloy).
- the Al alloy is, for example, an Al—Cu alloy.
- the IDT electrode 3 may be composed of a plurality of metal layers. Various dimensions of the IDT electrode 3 are appropriately set according to electrical characteristics required for the SAW element 1.
- the thickness (z direction) of the IDT electrode 3 is, for example, 50 nm to 600 nm.
- the IDT electrode 3 may be disposed directly on the upper surface 2A of the piezoelectric substrate 2 or may be disposed on the upper surface 2A of the piezoelectric substrate 2 via another member.
- This another member is made of, for example, Ti, Cr, or an alloy thereof.
- the thickness of the other member has a thickness that hardly affects the electrical characteristics of the IDT electrode 3 (for example, made of Ti) Is set to 5% of the thickness of the IDT electrode 3).
- a mass-added film may be laminated on the electrode finger 32 constituting the IDT electrode 3 in order to improve the temperature characteristics of the SAW element 1.
- the mass addition film for example, SiO 2 can be used.
- the IDT electrode 3 excites an elastic wave propagating in the x direction in the vicinity of the upper surface 2A of the piezoelectric substrate 2 when a voltage is applied.
- the excited elastic wave is reflected at the boundary with the non-arranged region of the electrode fingers 32 (the long region between the adjacent electrode fingers 32).
- the standing wave which makes the 1st pitch Pt1a of the electrode finger 32 of the main area
- the standing wave is converted into an electric signal having the same frequency as that of the standing wave, and is taken out by the electrode finger 32.
- the SAW element 1 functions as a 1-port resonator.
- the reflector 4 is formed so as to form a slit between the plurality of reflector electrode fingers 42.
- the reflector 4 includes a plurality of reflector bus bars 41 facing each other in a direction crossing the propagation direction of the elastic wave, and a plurality of extending in a direction perpendicular to the propagation direction of the elastic wave so as to connect the bus bars 41 between the bus bars 41.
- Reflector electrode finger 42 For example, the reflector bus bar 41 is formed in an elongated shape extending in a straight line with a substantially constant width, and is disposed in parallel with the propagation direction of the elastic wave.
- the interval between the adjacent reflector bus bars 41 can be set to be substantially the same as the interval between the adjacent bus bars 31 of the IDT electrode 3, for example.
- the plurality of reflector electrode fingers 42 are arranged at a pitch Pt2 that reflects the elastic wave excited by the IDT electrode 3.
- the pitch Pt2 will be described later.
- the pitch Pt2 indicates the distance between the center of the reflector electrode finger 42 and the center of the reflector electrode finger 42 adjacent thereto in the propagation direction, as shown in FIG.
- the plurality of reflector electrode fingers 42 are formed in a long shape extending in a straight line with a substantially constant width.
- the width w2 of the reflector electrode finger 42 can be set to be substantially the same as the width w1 of the electrode finger 32, for example.
- the reflector 4 is made of the same material as the IDT electrode 3 and has a thickness equivalent to that of the IDT electrode 3.
- the protective layer 5 is provided on the piezoelectric substrate 2 so as to cover the IDT electrode 3 and the reflector 4. Specifically, the protective layer 5 covers the surfaces of the IDT electrode 3 and the reflector 4 and covers the portion exposed from the IDT electrode 3 and the reflector 4 in the upper surface 2A.
- the thickness of the protective layer 5 is, for example, 1 nm to 50 nm.
- the protective layer 5 is made of an insulating material, and contributes to protecting the IDT electrode 3 and the reflector 4 from corrosion and the like.
- the protective layer 5 is made of a material such as SiO 2 that increases the propagation speed of the elastic wave when the temperature rises, thereby suppressing a change in electrical characteristics due to a change in the temperature of the elastic wave element 1. You can also
- the electrode finger design of the end region 3b located on the end side of the main region 3a and the electrode finger design of the reflector 4 are set as follows.
- the IDT electrode 3 includes a main region 3a and an end region 3b.
- the electrode finger design of the main region 3 a is uniform, and the electrode finger design determines the excitation frequency of the entire IDT electrode 3. That is, the electrode finger is designed with constant design parameters such as the pitch, width, and thickness of the electrode finger 32 in accordance with a desired excitation frequency.
- the end region 3b refers to a region extending from a part to be modulated from the uniform electrode finger design of the main region 3a to the end.
- module means changing at least one of the design parameters of the pitch of the electrode fingers 32 (interval between the centers of the electrode fingers 32), the gap (gap between the electrode fingers 32), the width, and the thickness.
- the number of electrode fingers 32 constituting the main region 3a and the number of electrode fingers 32 constituting the end region 3b are determined so that the resonance frequency according to the electrode finger design of the main region 3a determines the excitation frequency of the IDT electrode 3 as a whole. Set as appropriate. Specifically, the number of electrode fingers 32 constituting the main region 3a may be made larger than the number of electrode fingers 32 constituting the end region 3b.
- FIG. 19 shows an enlarged cross-sectional view of the main part of the IDT electrode 3 and the reflector 4.
- the electrode finger 32 positioned closest to the end region 3b in the main region 3a is defined as the electrode finger A
- the electrode finger 32 adjacent thereto is the main region 3a in the end region 3b.
- the electrode finger 32 positioned on the side of the first electrode is referred to as an electrode finger B
- the reflector electrode finger 42 positioned closest to the IDT electrode 3 among the reflectors 4 is referred to as a reflector electrode finger C.
- the distance between the center of the width of the electrode finger 32 and the center of the width of the electrode finger 32 adjacent thereto is a (the first pitch Pt1a described above), and the electrodes constituting the end region 3b.
- x is larger than 0.5 ⁇ a ⁇ (m + 1), and a ⁇ The value is smaller than (m + 1).
- the distance between the electrode finger A and the reflector electrode finger C is set so that the end region 3b is uniform between the main region 3a and the end region 3b without modulation of the electrode finger design. It can be made smaller compared to the case where Thereby, the part (henceforth an arrangement
- the distance between the electrode finger A and the reflector electrode finger C is changed by changing the gap Gp that is the gap between the adjacent first electrode finger 32a and the second electrode finger 32b.
- the adjacent electrode fingers 32 (the first electrode finger 32a and the second electrode finger 32b in the main region 3a).
- the second gap Gp2 that is the gap between the electrode finger A and the electrode finger B may be set to be narrower than the first gap Gp1 that is the gap.
- the second gap Gp2 that is smaller than the first gap Gp1 becomes the changing portion 300.
- the repeated arrangement of the IDT electrode 3 will be examined.
- the repeated arrangement of the electrode fingers 32 of the IDT electrode 3 includes, for example, the center of the first electrode finger 32a and the center of the first electrode finger 32a located adjacent to the second electrode finger 32b. Is repeated in one cycle.
- FIG. 6 is an example in which the center of the second electrode finger 32b is set to have the maximum displacement. Assume a repetition period caused by such a repetitive arrangement.
- the repetitive array of IDT electrodes 3 in the main region 3a is extended to the end side while maintaining the same period, and the repetitive array of IDT electrodes 3 in the end region 3b is maintained in the main period while maintaining the same period.
- An extension to the region 3a side is shown.
- the two repeat sequences are compared.
- the phase of the repetition period assumed by the repeated arrangement of the IDT electrodes 3 in the end region 3b is shifted to the main area 3a side compared to the phase of the repetition period assumed by the repeated arrangement of the IDT electrodes 3 in the main area 3a. ing.
- the resonance frequency determined by the electrode finger design of the reflector 4 has It is set lower than the resonance frequency determined by the electrode finger design.
- the resonance frequency of the reflector 4 increases when the pitch Pt2 is narrowed and decreases when the pitch Pt2 is widened. Therefore, in order to make the resonance frequency of the reflector 4 lower than the resonance frequency of the main region 3a of the IDT electrode 3, the pitch Pt2 of the reflector electrode fingers 42 of the reflector 4 is set to the pitch Pt in the main region 3a of the IDT electrode 3. What is necessary is just to set so that it may become wider than (1st pitch Pt1a).
- the frequency characteristic of the SAW element is determined.
- a simulation was performed. First, conditions for simulating a conventional SAW element as Comparative Example 1 are as follows.
- FIG. 7 shows the results of the SAW element of Comparative Example 1 calculated under such simulation conditions.
- the horizontal axis indicates the frequency
- the vertical axis indicates the absolute value
- FIG.7 (b) expands the location enclosed with the dashed-dotted line of Fig.7 (a). From this result, it can be seen that spurious is generated around 890 MHz, which is a frequency lower than the resonance frequency of about 900 MHz. This is considered to be due to the occurrence of reflector mode spurious in the SAW element in which the vibration intensity increases in the reflector.
- FIG. 8 shows the result of the SAW element of Example 1 calculated under such simulation conditions.
- the horizontal axis indicates the frequency
- the vertical axis indicates the impedance absolute value
- FIG.8 (b) expands the location enclosed with the dashed-dotted line of Fig.8 (a).
- the end region 3b located on the end side of the main region 3a has the changing portion 300, thereby reducing the spurious in the reflector mode.
- the impedance generated at around 890 MHz is reduced. It can be seen that spurious can be reduced.
- the end region 3b is configured by a region including eight electrode fingers from the end of the IDT electrode 3 and before the ninth electrode finger.
- the horizontal axis is the second gap Gp2
- the vertical axis is the maximum phase peak of the spurious outside the passband.
- the maximum phase peak is a phase value indicating the largest spurious outside the passband, and the greater the difference from ⁇ 90 deg, the larger the spurious.
- the maximum phase peak of Comparative Example 1 is indicated by a broken line extending parallel to the horizontal axis. From the results shown in FIG. 9, it can be seen that the above-described effect can be obtained by setting the second gap Gp2 to 0.87 times or more and smaller than the first gap Gp1. Further, from the result shown in FIG. 9, when the second gap Gp2 is set to 0.90 times the first gap Gp1, the maximum phase peak of spurious is substantially eliminated (the result shown in FIG. 9 corresponds to ⁇ 90 deg). Therefore, it can be seen that spurious can be greatly reduced.
- the comparative example 1 has (I) an end region including a change portion on the end side of the main region 3a.
- a simulation was carried out for the case of the case (Comparative Example 2) and the case (II) where only the resonance frequency of the reflector was set to a predetermined value (Comparative Example 3).
- Comparative Example 2 the resonance frequency of the reflector is equivalent to that of the main region 3a, and in Comparative Example 3, the IDT electrodes 3 are all designed to have a uniform electrode finger.
- Table 1 shows a correspondence table between Example 1 and Comparative Examples 1 to 3.
- the column of the second gap Gp2 indicates the magnification with respect to the first gap Gp1. Specifically, in the SAW element of Comparative Example 2, the second gap Gp2 is set to 0.90 times the first gap Gp1. In Table 1, the column of the pitch Pt2 of the reflector 4 indicates the magnification of the IDT electrode 3 with respect to the first pitch Pt1a.
- FIG. 10 shows the result of simulation under the condition of the SAW element of Comparative Example 2
- FIG. 11 shows the result of simulation under the condition of the SAW element of Comparative Example 3.
- the horizontal axis indicates the frequency
- the vertical axis indicates the absolute value
- the frequency is around 890 MHz that was generated in the SAW element of Comparative Example 1.
- the spurious can be reduced, a large spurious is generated near 895 MHz near the resonance frequency. This is presumably because a vibration mode (so-called longitudinal mode) having a plurality of peaks is generated in the IDT electrode 3 along the propagation direction of the elastic wave.
- the end region 3b including the changing portion 300 on the end side with respect to the main region 3a, and (II) the resonance frequency of the reflector are predetermined.
- the reflection frequency region of the reflector 4 can be shifted to a lower frequency side than the resonance frequency in the main region 3a. For this reason, when the SAW element 1 is operated at a frequency lower than the resonance frequency of the main region 3a, the elastic wave generated in the main region 3a can be prevented from leaking from the reflector 4. Thereby, loss at a frequency lower than the resonance frequency of the main region 3a can be reduced.
- the ripple and loss at the center of the pass band can be improved, and the characteristics in the reception band or the transmission band can be improved.
- the changing portion of the gap between the electrode finger A and the electrode finger B, which becomes the changing portion, is set between the eighth and ninth from the end, but this setting is changed. Even so, the range in which the above-described effects were exhibited was examined.
- simulation was performed by changing the positions of the electrode finger A and the electrode finger B. The result of the simulation is shown in FIG. In the graph shown in FIG. 12, the horizontal axis indicates the position of the electrode finger B by the number m from the end (between the m-th and m + 1-th), and the vertical axis is the maximum phase peak of spurious.
- FIG. 12 shows the minimum value of the maximum spurious phase peak for each number m.
- the spurious maximum phase peak can be reduced more than the SAW element of Comparative Example 1 even when the number m is zero.
- the distance between the IDT electrode 3 and the reflector 4 is changed in the decreasing direction, and the electrode finger 32 does not exist in the end region 3b. Even in this case, the distance between the electrode finger B and the reflector electrode finger C is closer than the original distance. From the above results, when the position of the electrode finger B is indicated by the number m from the end, the changing portion of the gap that exhibits the above effect is set in the range of 0 ⁇ m ⁇ 70.
- the portion where the electrode finger design is modulated in the IDT electrode 3 is only the second gap Gp2. That is, the gap between the electrode fingers 32 adjacent in the end region 3b is equal to the first gap Gp1, and the electrode finger width, electrode finger thickness, and pitch are equal to those of the main region 3a.
- the width w1a of the electrode finger 32 (electrode finger B) is set narrower than the width w1 of the electrode finger 32 in the main region 3a, and the second The gap Gp2 may be set to be the same as the first gap Gp1. Also by setting in this way, the entire array portion of the IDT electrodes 3 on the end side with respect to the changing portion 300 can be shifted to the array portion side of the IDT electrodes 3 in the main region 3a.
- the region closer to the end than the electrode finger A becomes the end region 3b, and the end region 3b includes the changing portion 300.
- Electrode finger 32 of IDT electrode 3 Position of change part 300 (position of electrode finger B): 9th (from end of IDT electrode 3) Width w1a of electrode finger 32 of change part 300: Width w1 ⁇ 0.90 of electrode finger 32 of main region 3a [Reflector 4] Pitch Pt2 of reflector electrode fingers 42: first pitch Pt1a ⁇ 1.02
- FIG. 14 shows the result of the SAW element of Example 2 calculated under such simulation conditions.
- the horizontal axis represents frequency
- the vertical axis represents impedance absolute value
- FIG.14 (b) expands the location enclosed with the dashed-dotted line of Fig.14 (a).
- the width w1a of the electrode finger 32 (electrode finger B) of the IDT electrode 3 located on the end side of the main region 3a is changed by one.
- the spurious in the longitudinal mode is reduced as in the first embodiment, and in the first comparative example, the spurious is generated around 890 MHz. It is possible to reduce the spurious impedance.
- the width w1a of the electrode finger 32 was changed to simulate a range effective for the comparative example 1.
- the result is shown in FIG.
- the horizontal axis indicates the width (w1a / w1) of the electrode finger B (the electrode finger 32 of the changing unit 300) with respect to the width of the electrode finger 32 in the main region 3a
- the vertical axis indicates the maximum phase of the spurious. It is a peak.
- the maximum phase peak in the SAW element of Comparative Example 1 is indicated by a broken line parallel to the horizontal axis. From this result, by setting the width w1a of the electrode finger 32 to 0.877 times or more and smaller than the width w1 of the electrode finger 32 in the main area 3a, the effect can be obtained as compared with Comparative Example 1. I understand that there is.
- Example 2 (Other method 2 for controlling the distance between the electrode finger A and the reflector electrode finger C)
- the distance between the electrode finger A and the reflector electrode finger C is adjusted by adjusting the gap between the electrode finger A and the electrode finger B or adjusting the width of the electrode finger B.
- the resonance frequency of the IDT electrode 3 located in the main region 3a and the end region 3b can be changed by adjusting the pitch Pt1 of the IDT electrode 3.
- the pitch Pt1 may be narrowed to increase the resonance frequency, and the pitch Pt1 may be widened to decrease the resonance frequency. Therefore, in the IDT electrode 3, in order to set the resonance frequency of the main region 3a to be lower than the resonance frequency of the end region 3b, the first pitch Pt1a is set to be wider than the second pitch Pt1b. Good.
- the frequency characteristic of the SAW element was simulated.
- FIG. 20 shows the results of the SAW element according to the present embodiment calculated under such simulation conditions.
- the horizontal axis represents frequency
- the vertical axis represents the absolute value
- all the IDT electrodes 3 located in the end region 3b have the first pitch Pt1a.
- FIG. 20B is an enlarged view of a portion surrounded by a dashed line in FIG. From this result, it can be seen that the spurious generated around 890 MHz in Comparative Example 1 can be reduced.
- Comparative Example 4 the case where only the resonance frequency of the end region 3b is set to a predetermined value is referred to as Comparative Example 5 ( II) A simulation was applied to each case where only the resonance frequency of the reflector was set to a predetermined value.
- the resonance frequency of the reflector is equivalent to the main region 3a of the IDT electrode 3, and in Comparative Example 5, the electrode finger design of the IDT electrode 3 is uniform.
- Table 2 shows a correspondence table of Example 3 and Comparative Examples 1, 4, and 5.
- the column of the second pitch Pt1b indicates the magnification with respect to the first pitch Pt1a. Specifically, in the SAW element of Comparative Example 4, the second pitch Pt1b is set to 0.990 times the first pitch Pt1a. In Table 2, the pitch Pt2 column of the reflector 4 indicates the magnification of the IDT electrode 3 with respect to the first pitch Pt1a.
- FIG. 21 shows the result of simulation under the conditions of the SAW element of Comparative Example 4
- FIG. 22 shows the result of simulation under the conditions of the SAW element of Comparative Example 5.
- the horizontal axis represents frequency
- the vertical axis represents the absolute value
- the resonance frequency of the end region 3b and (II) the resonance frequency of the reflector are set to predetermined values, so that the reflector mode Since spurious can be reduced and spurious in the longitudinal mode can be reduced, spurious generated at a frequency lower than the passband can be reduced.
- the second pitch Pt1b is 0.986 times or more than the first pitch Pt1a and is set to be smaller than one time, thereby providing the above-described effect. Further, from the result shown in FIG. 23, when the second pitch Pt1b is 0.991 ⁇ Pt1a, the maximum phase peak of spurious can be substantially eliminated (corresponding to ⁇ 90 deg in the result shown in FIG. 23). It can be seen that spurious can be greatly reduced.
- the end region 3b is set to 12 pieces from the end of the IDT electrode 3.
- the range in which the above effect can be obtained is examined. I did it.
- a simulation was performed by changing the number of electrode fingers 32 in the end region 3b. The result of the simulation is shown in FIG.
- the horizontal axis represents the number m of electrode fingers 32 in the end region 3b
- the vertical axis represents the maximum phase peak of spurious.
- the second pitch Pt1b was adjusted so that the maximum phase peak of spurious was minimized.
- FIG. 24 shows the minimum value of the maximum phase peak of spurious for each number m.
- the number m of the end regions 3b is set to 70 or more, the maximum phase peak of spurious is larger than that of Comparative Example 1 and the characteristics are deteriorated. Therefore, the number m is less than 70. By doing so, it can be seen that the above-described effect is achieved. As a result, when the number m is 12, the maximum spurious phase peak can be set to ⁇ 90 deg. Therefore, it can be understood that the spurious can be significantly reduced. On the other hand, it can be seen from FIG. 24 that even when the number m is 0, the maximum phase peak of spurious can be reduced as compared with the SAW element of Comparative Example 1. When the number m is 0, the distance between the IDT electrode 3 and the reflector 4 is changed. From the above results, the number m of the electrode fingers 32 in the end region 3b in the SAW element 1 is set in a range of 0 ⁇ m ⁇ 70.
- the duty of the IDT electrode 3 is set such that the width w1 of the second electrode finger 32b is second from the end of the first electrode finger 32a on one side of the second electrode finger 32b in the propagation direction of the elastic wave. This is a value divided by the distance Dt1 to the other end of the electrode finger 32b.
- the duty may be reduced to increase the resonance frequency of the IDT electrode 3, and the resonance frequency of the IDT electrode 3 is increased.
- the duty may be increased. Therefore, the IDT electrode 3 positioned in the end region 3b is set so that its duty is smaller than the duty of the IDT electrode 3 positioned in the main region 3a.
- FIG. 25 shows the result of the SAW element of Example 4 calculated under such simulation conditions.
- the horizontal axis represents frequency
- the vertical axis represents the absolute value
- FIG. 25B is an enlarged view of a portion surrounded by a one-dot chain line in FIG. In this simulation, all the duties of the IDT electrode 3 located in the end region 3b are changed.
- the spurious in the longitudinal mode is reduced as in the third embodiment, and in the first comparative example, the spurious is generated around 890 MHz. Impedance spurious can be reduced.
- the method of changing the pitch Pt2 as the method of changing the resonance frequency of the reflector 4 has been described.
- the duty of the reflector electrode 42 is described.
- a method of changing the film thickness s between the electrode finger 32 and the reflector electrode finger 42 can be used.
- the design parameters (number, intersection width, pitch, duty, electrode thickness, frequency, etc.) that are electrode finger designs are shown only in a specific case.
- the element also has the effect of reducing spurious.
- the position (number from the end) of the changing portion 300 and the gap Gp (first gap Gp1) similar to those of the first embodiment , The second gap Gp2) was confirmed by simulation to exhibit a good spurious suppression effect.
- the resonance frequency by the electrode finger design of the end region 3b is made higher than the resonance frequency by the electrode finger design of the main region 3a. May be set.
- the second frequency of the IDT electrode 3 located in the end region 3b is set.
- the pitch Pt1b may be narrowed.
- the second pitch Pt1b of the IDT electrodes 3 located in the end region 3b is, for example, 0.986 times or more and smaller than 1 times the first pitch Pt1a of the IDT electrodes 3 located in the center region 3a. Set to range. With this configuration, the distance between the electrode finger A and the reflector electrode finger C can be further set to a desired relationship.
- a plurality of resonators having various numbers and crossing widths are combined to exhibit characteristics.
- the SAW element of the present invention is used as a resonator, the IDT is compared with the plurality of resonators. Design values for electrodes and reflectors can be set. For this reason, even when the SAW element of the present invention is used for a filter or a duplexer, the design can be performed in the same manner as when a conventional acoustic wave element is used.
- the position of the changing portion 300 (number m from the end portion), the gap Gp, etc. may be set to optimal values as appropriate.
- a simulation using a mode coupling method (COM (Coupling-Of-Modes) method) may be used.
- COM Coupling-Of-Modes
- the spurious can be satisfactorily reduced by performing simulation by changing the position (number m from the end portion) of the changing portion 300, the gap Gp, and the like. You can find the conditions.
- the number m of electrode fingers 32 constituting the end region 3b is an ideal number depending on the total number of electrode fingers 32 constituting the IDT electrode 3, but this can be determined by simulation using the COM method. . Further, spurious can be reduced even if the ideal number is deviated. In the range of the total number of electrode fingers 43 (about 50 to 500) constituting the IDT electrode 3 generally designed as the SAW element 1, the number m is about 5 to 20 and good characteristics are obtained. Make sure you can.
- FIG. 16 is a block diagram showing a main part of the communication apparatus 101 according to the embodiment of the present invention.
- the communication device 101 performs wireless communication using radio waves.
- the duplexer 7 has a function of demultiplexing a signal having a transmission frequency and a signal having a reception frequency in the communication apparatus 101.
- a transmission information signal TIS including information to be transmitted is modulated and increased in frequency (converted into a high frequency signal of a carrier frequency) by the RF-IC 103 to be a transmission signal TS.
- Unnecessary components other than the transmission passband are removed from the transmission signal TS by the bandpass filter 105, amplified by the amplifier 107, and input to the duplexer 7.
- the duplexer 7 removes unnecessary components other than the transmission passband from the input transmission signal TS and outputs the result to the antenna 109.
- the antenna 109 converts the input electric signal (transmission signal TS) into a radio signal and transmits it.
- the radio signal received by the antenna 109 is converted into an electric signal (reception signal RS) by the antenna 109 and input to the duplexer 7.
- the duplexer 7 removes unnecessary components other than the reception passband from the input reception signal RS and outputs the result to the amplifier 111.
- the output reception signal RS is amplified by the amplifier 111, and unnecessary components other than the reception passband are removed by the bandpass filter 113.
- the reception signal RS is subjected to frequency reduction and demodulation by the RF-IC 103 to be a reception information signal RIS.
- the transmission information signal TIS and the reception information signal RIS may be low-frequency signals (baseband signals) including appropriate information, for example, analog audio signals or digitized audio signals.
- the passband of the radio signal may be in accordance with various standards such as UMTS (Universal Mobile Telecommunications System).
- the modulation method may be any of phase modulation, amplitude modulation, frequency modulation, or a combination of any two or more thereof.
- FIG. 17 is a circuit diagram showing a configuration of the duplexer 7 according to one embodiment of the present invention.
- the duplexer 7 is the duplexer 7 used in the communication apparatus 101 in FIG.
- the SAW element 1 is, for example, a SAW element that constitutes a ladder type filter circuit of the transmission filter 11 in the duplexer 7 shown in FIG.
- the transmission filter 11 includes a piezoelectric substrate 2, and series resonators S1 to S3 and parallel resonators P1 to P3 formed on the piezoelectric substrate 2.
- the duplexer 7 includes an antenna terminal 8, a transmission terminal 9, a reception terminal 10, a transmission filter 11 disposed between the antenna terminal 8 and the transmission terminal 9, and between the antenna terminal 8 and the reception terminal 10.
- the reception filter 12 is mainly configured.
- the transmission signal TS from the amplifier 107 is input to the transmission terminal 9, and the transmission signal TS input to the transmission terminal 9 is output to the antenna terminal 8 by removing unnecessary components other than the transmission passband in the transmission filter 11. Is done. Further, the reception signal RS is input from the antenna 109 to the antenna terminal 8, and unnecessary components other than the reception passband are removed by the reception filter 12 and output to the reception terminal 10.
- the transmission filter 11 is configured by, for example, a ladder-type SAW filter.
- the transmission filter 11 includes three series resonators S1, S2, and S3 connected in series between the input side and the output side, and a series arm that is a wiring for connecting the series resonators to each other. And three parallel resonators P1, P2, and P3 provided between the reference potential portion G and the reference potential portion G. That is, the transmission filter 11 is a ladder filter having a three-stage configuration. However, the number of stages of the ladder filter in the transmission filter 11 is arbitrary.
- An inductor L is provided between the parallel resonators P1 to P3 and the reference potential portion G. By setting the inductance of the inductor L to a predetermined magnitude, an attenuation pole is formed outside the transmission signal pass band to increase the out-of-band attenuation.
- the plurality of series resonators S1 to S3 and the plurality of parallel resonators P1 to P3 are each composed of a SAW resonator.
- the reception filter 12 includes, for example, a multimode SAW filter 17 and an auxiliary resonator 18 connected in series on the input side thereof.
- the multiplex mode includes a double mode.
- the multi-mode SAW filter 17 has a balanced-unbalanced conversion function, and the receiving filter 12 is connected to two receiving terminals 10 that output balanced signals.
- the reception filter 12 is not limited to the multimode SAW filter 17 but may be a ladder filter or a filter that does not have a balanced-unbalanced conversion function.
- an impedance matching circuit made of an inductor or the like may be inserted.
- the filter characteristics of the duplexer 7 can be improved.
- the filter characteristics of the duplexer when the SAW element 1 using the SAW element structure of Example 1 is applied to the series resonators S1 to S3 of the transmission filter 11 were calculated by simulation.
- the passband of the duplexer 7 is assumed to be the UMTS Band 2 transmission side.
- the result is shown in FIG. In the graph shown in FIG. 18, the horizontal axis represents frequency (MHz), and the vertical axis represents pass characteristics (dB).
- the broken line indicates the filter characteristics when the SAW element of Comparative Example 1 is used, and the solid line indicates the filter characteristics when the SAW element 1 of Example 1 is used. From the results shown in FIG. 18, it can be seen that transmission characteristics in a frequency band lower than 1860 MHz can be improved in the transmission-side pass band.
- the resonance frequency of the series resonators S1 to S3 is set near the center of the filter pass band. Further, the antiresonance frequency of the parallel resonators P1 to P3 is set near the center of the filter pass band. In such a frequency arrangement, when the acoustic wave device of the present invention is used for the series resonators S1 to S3, loss and ripple near the center of the filter passband can be improved.
- a spurious peak (occurring in the vicinity of 960 MHz in FIG. 7A) generated on the higher frequency side than the antiresonance frequency is on the lower frequency side.
- FIG. 8A it is shifted by -10 MHz around 950 MHz).
- This is considered to be one of the causes that the operating band of the reflector is shifted to the low frequency side as the resonant frequency of the reflector is lowered.
- the SAW element 1 is improved in electrical characteristics near the resonance frequency due to spurious generated around the operating band edge of the reflector, but the loss in the high frequency region is worse than the anti-resonance frequency.
- the frequency at which the loss is deteriorated overlaps the higher frequency side than the center of the filter pass band.
- the loss of the filter may be worsened depending on the design. Therefore, in the ladder type filter, by using the SAW element 1 only for a part of the series resonator, the pass characteristic can be remarkably improved while the deterioration of the filter characteristic is reduced. If the anti-resonance frequency of the parallel resonator of the ladder filter is designed not to fall within the pass band of the filter, the SAW element 1 can be used as the parallel resonator.
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
Description
図1は、本発明の一実施形態に係る弾性波(SAW:Surface Acoustic Wave)素子1の構成を示す平面図である。図2は図1のIc-Ic切断線における一部の断面図である。SAW素子1は、図1に示すように、圧電基板2、圧電基板2の上面2Aに設けられた励振電極(IDT(Interdigital Transducer)電極)3および反射器4を有している。
IDT電極3は、主領域3aと端部領域3bとを備える。主領域3aの電極指設計は一様であり、その電極指設計はIDT電極3全体の励振周波数を決定するものである。すなわち、所望の励振周波数に合わせて、電極指32のピッチ、幅、厚み等の設計パラメーターを一定にした電極指設計をしている。端部領域3bは、この主領域3aの一様な電極指設計から変調する部分から端部まで続く領域を指す。ここで「変調する」とは、電極指32のピッチ(電極指32の中心間の間隔)、ギャップ(電極指32間の隙間)、幅、厚みの設計パラメーターの少なくとも1つを変化させることをいう。主領域3aを構成する電極指32の本数と端部領域3bを構成する電極指32の本数とは、主領域3aの電極指設計による共振周波数がIDT電極3全体の励振周波数を決定するように適宜設定する。具体的には、主領域3aを構成する電極指32の本数を、端部領域3bを構成する電極指32の本数よりも多くすればよい。
上記電極指Aと反射器電極指Cと位置関係の設定に加えて、反射器4の電極指設計で決まる共振周波数が、IDT電極3の主領域3aの電極指設計で決まる共振周波数よりも低く設定されている。反射器4の共振周波数は、ピッチPt2を狭くすると高くなり、ピッチPt2を広くすると低くなる。そのため、反射器4の共振周波数をIDT電極3の主領域3aの共振周波数よりも低くするには、反射器4の反射器電極指42のピッチPt2を、IDT電極3の主領域3aにおけるピッチPt(第1ピッチPt1a)よりも広くなるように設定すればよい。
[圧電基板2]
材料:42°YカットX伝播LiTaO3基板
[IDT電極3]
材料:Al-Cu合金(ただし、圧電基板2と導電層15との間には6nmのTiからなる下地層あり。)
厚さ(Al-Cu合金層):324nm
IDT電極3の電極指32:
本数:100本
第1ピッチPt1a:2.19μm
デューティー(w1/Pt1):0.5
交差幅W:65.7μm(15λ)
[反射器4]
材料:Al-Cu合金(ただし、圧電基板2と導電層15との間には6nmのTiからなる下地層あり。)
厚さ(Al-Cu合金層):324nm
反射器電極指42の本数:30本
反射器電極指42のピッチPt2:2.19μm(Pt1a×1.00)
[保護層5]
材料:SiO2
厚さ:15nm
このようなシミュレーションの条件で計算した比較例1のSAW素子の結果を図7に示す。図7に示すグラフは、横軸に周波数を、縦軸にインピーダンスの絶対値|Z|またはインピーダンスの位相を示している。また、図7(b)は、図7(a)の一点鎖線で囲んだ箇所を拡大したものである。この結果から、共振周波数である約900MHzよりも低い周波数の890MHz前後にスプリアスが発生していることが分かる。これは、SAW素子において、反射器内で振動強度が大きくなる反射器モードのスプリアスが発生していることが原因の1つであると考えられる。
[IDT電極3]
IDT電極3の電極指32:
第2ギャップGp2の位置:(IDT電極3の端部から)8本目と9本目との間
第2ギャップGp2:第1ギャップGp1×0.90
[反射器4]
反射器電極指42のピッチPt2:第1ピッチPt1a×1.02
このようなシミュレーションの条件で計算した実施例1のSAW素子の結果を図8に示す。図8に示すグラフは、横軸に周波数を、縦軸にインピーダンスの絶対値|Z|またはインピーダンスの位相を示している。また、図8(b)は、図8(a)の一点鎖線で囲んだ箇所を拡大したものである。
上述の例では、IDT電極3の端部領域3bの電極指設計として、IDT電極3の第2ギャップGp2を変化させる方法を説明したが、変化部300としてIDT電極3の電極指32の幅w1aを変化させてもよい。
[IDT電極3]
IDT電極3の電極指32:
変化部300の位置(電極指Bの位置):(IDT電極3の端部から)9本目
変化部300の電極指32の幅w1a:主領域3aの電極指32の幅w1×0.90
[反射器4]
反射器電極指42のピッチPt2:第1ピッチPt1a×1.02
このようなシミュレーションの条件で計算した実施例2のSAW素子の結果を図14に示す。図14に示すグラフは、横軸に周波数を、縦軸にインピーダンスの絶対値|Z|またはインピーダンスの位相を示している。また、図14(b)は、図14(a)の一点鎖線で囲んだ箇所を拡大したものである。なお、本シミュレーションは、主領域3aよりも端部側に位置するIDT電極3の電極指32(電極指B)の幅w1aを1つ変化させた場合である。
この結果から、電極指32の幅w1aを主域3aの電極指32の幅w1に対して0.877倍以上であり、且つ1倍よりも小さく設定することにより、比較例1に比べて効果があることが分かる。
上述の実施例1および実施例2では、電極指Aと電極指Bとのギャップを調整したり電極指Bの幅を調整したりすることで、電極指Aと反射器電極指Cとの距離について所望の条件を満たしたが、端部領域3bの電極指設計で決まる共振周波数を、主領域3aの電極指設計で決まる共振周波数よりも高くすることで実現してもよい。
[IDT電極3]
IDT電極3の電極指32:
端部領域3bの電極指32の本数:(IDT電極3の端部から)12本
第2ピッチPt1b:第1ピッチPt1a×0.990
[反射器4]
反射器電極指42のピッチPt2:第1ピッチPt1a×1.02
このようなシミュレーションの条件で計算した本実施形態に係るSAW素子の結果を図20に示す。図20に示すグラフは、横軸に周波数を、縦軸にインピーダンスの絶対値|Z|またはインピーダンスの位相を示している。なお、本実施例3では、端部領域3bに位置するIDT電極3を全て第1ピッチPt1aとした場合である。図20(b)は、図20(a)の一点鎖線で囲んだ箇所を拡大したものである。この結果から、比較例1では890MHz前後に発生していたスプリアスが低減できていることが分かる。
[IDT電極3]
本数:200本
[反射器4]
ピッチPt2:第1ピッチPt1a×1.02
このような条件の下、第2ピッチPt1bを変化させて計算を行なった。その結果を図23に示す。図23に示すグラフは、横軸が第2ピッチPt1bであり、縦軸が通過帯域外のスプリアスの最大位相ピークである。また、比較例1のSAW素子における最大位相ピークを横軸と平行な破線で示している。
IDT電極3の端部領域3bの共振周波数を所定の値に設定する方法として、IDT電極3の第2ピッチPt1bを変化させる方法を説明したが、端部領域3bに位置するIDT電極3のデューティーを変化させてもよい。
[IDT電極3]
IDT電極3の電極指32:
端部領域3bの電極指32の本数:(IDT電極3の端部から)20本
端部領域3bの電極指32のデューティー:主領域3aの電極指32のデューティー×0.86
[反射器4]
反射器電極42のピッチPt2:第1ピッチPt1a×1.02
このようなシミュレーションの条件で計算した実施例4のSAW素子の結果を図25に示す。図25に示すグラフは、横軸に周波数を、縦軸にインピーダンスの絶対値|Z|またはインピーダンスの位相を示している。また、図25(b)は、図25(a)の一点鎖線で囲んだ箇所を拡大したものである。なお、本シミュレーションにおいては、端部領域3bに位置するIDT電極3のデューティーを全て変化させた。
図16は、本発明の実施形態に係る通信装置101の要部を示すブロック図である。通信装置101は、電波を利用した無線通信を行なうものである。分波器7は、通信装置101において送信周波数の信号と受信周波数の信号とを分波する機能を有している。
2 圧電基板
2A 上面
3 励振電極(IDT電極)
3a 主領域
3b 端部領域
30 櫛歯電極
30a 第1櫛歯電極
30b 第2櫛歯電極
31 バスバー
31a 第1バスバー
31b 第2バスバー
32 電極指
32a 第1電極指
32b 第2電極指
300 変化部
Pt1 ピッチ
Pt1a 第1ピッチ
Pt1b 第2ピッチ
Gp ギャップ
Gp1 第1ギャップ
Gp2 第2ギャップ
4 反射器
41 反射器バスバー
42 反射器電極指
Pt2 ピッチ
5 保護層
7 分波器
8 アンテナ端子
9 送信端子
10 受信端子
11 送信フィルタ
12 受信フィルタ
15 導電層
17 多重モード型SAWフィルタ
18 補助共振子
101 通信装置
103 RF-IC
105 バンドパスフィルタ
107 増幅器
109 アンテナ
111 増幅器
113 バンドパスフィルタ
S1、S2、S3 直列共振子
P1、P2、P3 並列共振子
Claims (16)
- 圧電基板と、
該圧電基板の上面に位置し、複数の電極指を有する、弾性波を発生させる励振電極と、
前記圧電基板の上面に位置し、複数の反射器電極指を有し、前記弾性波の伝搬方向において前記励振電極を挟む2つの反射器とを備え、
前記励振電極は、前記弾性波の伝搬方向の両端部間に位置する前記電極指の電極指設計が一様な主領域と、該主領域とは電極指設計が変調する部位から端部まで続く、前記主領域を挟んで両側に位置する2つの端部領域とを有し、
前記反射器は、前記反射器電極指の電極指設計で決まる共振周波数が前記主領域の前記電極指の電極指設計で決まる共振周波数よりも低く、
前記主領域において前記電極指の中心とこれに隣接する前記電極指の中心との間隔をaとし、前記端部領域を構成する前記電極指の数をmとし、前記主領域の前記電極指のうち最も前記端部領域の側に位置する前記電極指の中心と、前記反射器の前記反射器電極指のうち最も前記端部領域の側に位置する前記反射器電極指の中心との距離をxとすると、
0.5×a×(m+1)<x<a×(m+1)
を満たしている弾性波素子。 - 複数の前記電極指は、複数の第1電極指と複数の第2電極指とを有し、
前記励振電極は、前記複数の第1電極指を持つ第1櫛歯電極と、前記複数の第1電極指と噛み合う前記複数の第2電極指を持つ第2櫛歯電極とを有する請求項1に記載の弾性波素子。 - 前記主領域において隣接する2つの前記電極指の隙間である第1ギャップよりも、前記主領域の前記電極指のうち最も前記端部領域の側に位置する前記電極指と、これに隣接する、前記端部領域の前記電極指のうち最も前記主領域の側に位置する前記電極指との隙間である第2ギャップが狭い請求項1または2に記載の弾性波素子。
- 前記第2ギャップが、前記第1ギャップに対して0.87倍以上であり、且つ1倍よりも小さい請求項3に記載の弾性波素子。
- 前記端部領域の前記電極指のうち最も前記主領域の側に位置する前記電極指の幅が、前記主領域における前記電極指の幅よりも狭い請求項1または2に記載の弾性波素子。
- 前記端部領域の前記電極指のうち最も前記主領域の側に位置する前記電極指の幅が、前記主領域における前記第1電極指または前記第2電極指の幅に対して0.877倍以上であり、且つ1倍よりも小さい請求項5に記載の弾性波素子。
- 前記反射器は、前記反射器電極指の中心とこれに隣接する前記反射器電極指の中心との間隔が、前記主領域における前記電極指の中心とこれに隣接する前記電極指の中心との間隔よりも広い、請求項1乃至6のいずれかに記載の弾性波素子。
- 前記端部領域は、前記電極指の電極指設計で決まる共振周波数が、前記主領域の前記電極指の電極指設計で決まる共振周波数よりも高い、請求項1または2に記載の弾性波素子。
- 前記端部領域は、前記電極指の中心とこれに隣接する前記電極指の中心との間隔である第1ピッチが、前記主領域における前記電極指の中心とこれに隣接する前記電極指の中心との間隔である第2ピッチよりも狭い請求項8に記載の弾性波素子。
- 前記励振電極の前記第1ピッチが、前記第2ピッチに対して0.986倍以上であり、且つ1倍よりも小さい請求項9に記載の弾性波素子。
- 前記励振電極は、前記端部領域に位置する前記電極指の幅が、前記主領域に位置する前記電極指の幅よりも狭い請求項8乃至10のいずれかに記載の弾性波素子。
- 前記端部領域において隣接する2つの前記電極指の隙間は、前記第1ギャップと等しい請求項3または4に記載の弾性波素子。
- アンテナ端子と、送信信号をフィルタリングして前記アンテナ端子に出力する送信フィルタと、前記アンテナ端子からの受信信号をフィルタリングする受信フィルタとを備えた分波器であって、
前記送信フィルタまたは前記受信フィルタは、請求項1乃至12のいずれかに記載の弾性波素子を有する分波器。 - 前記送信フィルタは、それぞれが直列に接続した直列共振子と、該直列共振子に対して並列に接続した並列共振子とを有し、前記直列共振子の少なくとも一部が前記弾性波素子で構成されている請求項13に記載の分波器。
- 前記送信フィルタは、前記直列共振子のみが前記弾性波素子で構成されている請求項13に記載の分波器。
- アンテナと、
該アンテナに電気的に接続された請求項13乃至15のいずれかに記載の分波器と、
該分波器に電気的に接続されたRF-ICとを備える通信装置。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/039,810 US9978927B2 (en) | 2013-11-26 | 2014-11-29 | Acoustic wave element, duplexer and communication device |
JP2015551033A JP6595342B2 (ja) | 2013-11-29 | 2014-11-29 | 弾性波素子、分波器および通信装置 |
CN201480063282.8A CN105745840B (zh) | 2013-11-29 | 2014-11-29 | 弹性波元件、分波器以及通信装置 |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2013247163 | 2013-11-29 | ||
JP2013-247163 | 2013-11-29 | ||
JP2013268194 | 2013-12-26 | ||
JP2013-268194 | 2013-12-26 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2015080278A1 true WO2015080278A1 (ja) | 2015-06-04 |
Family
ID=53199213
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2014/081662 WO2015080278A1 (ja) | 2013-11-26 | 2014-11-29 | 弾性波素子、分波器および通信装置 |
Country Status (4)
Country | Link |
---|---|
US (1) | US9978927B2 (ja) |
JP (2) | JP6595342B2 (ja) |
CN (1) | CN105745840B (ja) |
WO (1) | WO2015080278A1 (ja) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170194936A1 (en) * | 2016-01-05 | 2017-07-06 | Handy International Co., Ltd. | Surface acoustic wave device, duplexer and comb-shaped electrode |
JPWO2017131170A1 (ja) * | 2016-01-29 | 2018-02-08 | 京セラ株式会社 | 弾性波共振子、弾性波フィルタ、分波器および通信装置 |
WO2018181111A1 (ja) * | 2017-03-30 | 2018-10-04 | 株式会社村田製作所 | マルチプレクサ、高周波フロントエンド回路及び通信装置 |
WO2019198594A1 (ja) * | 2018-04-11 | 2019-10-17 | 京セラ株式会社 | 弾性波素子、弾性波フィルタ、分波器および通信装置 |
KR20210031881A (ko) * | 2018-11-08 | 2021-03-23 | 가부시키가이샤 무라타 세이사쿠쇼 | 멀티플렉서 |
JP7008633B2 (ja) | 2016-10-13 | 2022-01-25 | 株式会社村田製作所 | 弾性波フィルタ装置 |
US11569433B2 (en) | 2017-04-07 | 2023-01-31 | Taiyo Yuden Co., Ltd. | Acoustic wave resonator, filter, and multiplexer |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109863695B (zh) * | 2016-10-28 | 2024-03-12 | 株式会社村田制作所 | 梯型滤波器、双工器以及弹性波滤波器装置 |
WO2018088118A1 (ja) * | 2016-11-09 | 2018-05-17 | 株式会社村田製作所 | 弾性波装置、高周波フロントエンド回路及び通信装置 |
CN110383688B (zh) * | 2017-03-13 | 2023-01-24 | 株式会社村田制作所 | 陷波滤波器 |
CN110089031B (zh) * | 2017-03-22 | 2024-02-23 | 京瓷株式会社 | 弹性波装置、分波器以及通信装置 |
CN110800213B (zh) * | 2017-07-06 | 2023-11-07 | 京瓷株式会社 | 弹性波元件、滤波器元件及通信装置 |
CN108428787B (zh) * | 2018-03-23 | 2021-06-01 | 北京航天微电科技有限公司 | 一种saw芯片及其制备方法、制备*** |
US11521500B1 (en) * | 2018-10-17 | 2022-12-06 | Amazon Technologies, Inc. | Unmanned aerial systems with range finding |
DE102018131952A1 (de) * | 2018-12-12 | 2020-06-18 | RF360 Europe GmbH | Elektroakustischer Resonator mit unterdrückter Anregungtransversaler Spaltmoden und verringerten transversalen Moden |
JP7374629B2 (ja) * | 2019-07-04 | 2023-11-07 | 太陽誘電株式会社 | 弾性波デバイス、フィルタおよびマルチプレクサ |
US20210273629A1 (en) * | 2020-02-28 | 2021-09-02 | Resonant Inc. | Transversely-excited film bulk acoustic resonator with multi-pitch interdigital transducer |
CN112448694A (zh) * | 2021-02-01 | 2021-03-05 | 成都频岢微电子有限公司 | 用于改善通带平坦度的dms滤波器及双工器 |
CN118202688A (zh) * | 2021-10-29 | 2024-06-14 | 联想(北京)有限公司 | Ris辅助的urllc***中的开销减少 |
CN115987246A (zh) * | 2023-02-02 | 2023-04-18 | 无锡市好达电子股份有限公司 | 高隔离度声表面波双工器及多工器 |
Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH03139008A (ja) * | 1989-10-24 | 1991-06-13 | Matsushita Electric Ind Co Ltd | 弾性表面波フィルタ |
JPH06260876A (ja) * | 1993-03-09 | 1994-09-16 | Mitsubishi Electric Corp | 弾性表面波フィルタ |
JP2002111442A (ja) * | 2000-09-28 | 2002-04-12 | Fujitsu Ltd | 弾性表面波共振器及びこれを用いた弾性表面波フィルタ |
JP2003008390A (ja) * | 2001-04-16 | 2003-01-10 | Murata Mfg Co Ltd | 弾性表面波装置、通信装置 |
JP2004363641A (ja) * | 2003-05-30 | 2004-12-24 | Seiko Epson Corp | 弾性表面波共振子 |
WO2006137464A1 (ja) * | 2005-06-21 | 2006-12-28 | Epson Toyocom Corporation | 弾性表面波デバイス、モジュール、及び発振器 |
JP2007013414A (ja) * | 2005-06-29 | 2007-01-18 | Seiko Epson Corp | 弾性表面波素子片、弾性表面波装置、及び電子機器 |
WO2010047113A1 (ja) * | 2008-10-24 | 2010-04-29 | エプソントヨコム株式会社 | 弾性表面波共振子、弾性表面波発振器および弾性表面波モジュール装置 |
WO2010047112A1 (ja) * | 2008-10-24 | 2010-04-29 | エプソントヨコム株式会社 | 弾性表面波共振子、弾性表面波発振器および弾性表面波モジュール装置 |
WO2010047114A1 (ja) * | 2008-10-24 | 2010-04-29 | エプソントヨコム株式会社 | 弾性表面波共振子、弾性表面波発振器および弾性表面波モジュール装置 |
JP2010273382A (ja) * | 2004-01-09 | 2010-12-02 | Panasonic Corp | 弾性表面波共振子及びこれを用いた弾性表面波フィルタ |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3358615B2 (ja) * | 2000-06-26 | 2002-12-24 | 株式会社村田製作所 | 縦結合共振子型弾性表面波フィルタ |
JP4059152B2 (ja) * | 2002-10-16 | 2008-03-12 | セイコーエプソン株式会社 | 弾性表面波共振子 |
KR100778226B1 (ko) * | 2004-04-19 | 2007-11-20 | 가부시키가이샤 무라타 세이사쿠쇼 | 탄성파 필터 및 그것을 사용한 통신기 |
JP2007202087A (ja) * | 2005-05-11 | 2007-08-09 | Seiko Epson Corp | ラム波型高周波デバイス |
JP2007214902A (ja) | 2006-02-09 | 2007-08-23 | Shin Etsu Chem Co Ltd | 弾性表面波素子 |
JP2012156741A (ja) * | 2011-01-26 | 2012-08-16 | Panasonic Corp | アンテナ共用器 |
JP5488680B2 (ja) * | 2012-12-11 | 2014-05-14 | セイコーエプソン株式会社 | 弾性表面波共振子、弾性表面波発振器および弾性表面波モジュール装置 |
JP2015073207A (ja) * | 2013-10-03 | 2015-04-16 | スカイワークス・パナソニック フィルターソリューションズ ジャパン株式会社 | 弾性波共振器 |
-
2014
- 2014-11-29 US US15/039,810 patent/US9978927B2/en active Active
- 2014-11-29 CN CN201480063282.8A patent/CN105745840B/zh active Active
- 2014-11-29 JP JP2015551033A patent/JP6595342B2/ja active Active
- 2014-11-29 WO PCT/JP2014/081662 patent/WO2015080278A1/ja active Application Filing
-
2018
- 2018-05-14 JP JP2018093142A patent/JP6595659B2/ja active Active
Patent Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH03139008A (ja) * | 1989-10-24 | 1991-06-13 | Matsushita Electric Ind Co Ltd | 弾性表面波フィルタ |
JPH06260876A (ja) * | 1993-03-09 | 1994-09-16 | Mitsubishi Electric Corp | 弾性表面波フィルタ |
JP2002111442A (ja) * | 2000-09-28 | 2002-04-12 | Fujitsu Ltd | 弾性表面波共振器及びこれを用いた弾性表面波フィルタ |
JP2003008390A (ja) * | 2001-04-16 | 2003-01-10 | Murata Mfg Co Ltd | 弾性表面波装置、通信装置 |
JP2004363641A (ja) * | 2003-05-30 | 2004-12-24 | Seiko Epson Corp | 弾性表面波共振子 |
JP2010273382A (ja) * | 2004-01-09 | 2010-12-02 | Panasonic Corp | 弾性表面波共振子及びこれを用いた弾性表面波フィルタ |
WO2006137464A1 (ja) * | 2005-06-21 | 2006-12-28 | Epson Toyocom Corporation | 弾性表面波デバイス、モジュール、及び発振器 |
JP2007013414A (ja) * | 2005-06-29 | 2007-01-18 | Seiko Epson Corp | 弾性表面波素子片、弾性表面波装置、及び電子機器 |
WO2010047113A1 (ja) * | 2008-10-24 | 2010-04-29 | エプソントヨコム株式会社 | 弾性表面波共振子、弾性表面波発振器および弾性表面波モジュール装置 |
WO2010047112A1 (ja) * | 2008-10-24 | 2010-04-29 | エプソントヨコム株式会社 | 弾性表面波共振子、弾性表面波発振器および弾性表面波モジュール装置 |
WO2010047114A1 (ja) * | 2008-10-24 | 2010-04-29 | エプソントヨコム株式会社 | 弾性表面波共振子、弾性表面波発振器および弾性表面波モジュール装置 |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107017860B (zh) * | 2016-01-05 | 2020-06-23 | 威盛日本株式会社 | 声表面波器件、天线收发转换开关及叉指式换能器 |
CN107017860A (zh) * | 2016-01-05 | 2017-08-04 | Handy国际株式会社 | 声表面波器件、天线收发转换开关及叉指式换能器 |
US20170194936A1 (en) * | 2016-01-05 | 2017-07-06 | Handy International Co., Ltd. | Surface acoustic wave device, duplexer and comb-shaped electrode |
US10298200B2 (en) * | 2016-01-05 | 2019-05-21 | Wisol Japan Co., Ltd. | Surface acoustic wave device, duplexer and comb-shaped electrode |
JPWO2017131170A1 (ja) * | 2016-01-29 | 2018-02-08 | 京セラ株式会社 | 弾性波共振子、弾性波フィルタ、分波器および通信装置 |
CN108496308A (zh) * | 2016-01-29 | 2018-09-04 | 京瓷株式会社 | 弹性波谐振器、弹性波滤波器、分波器及通信装置 |
US10389391B2 (en) | 2016-01-29 | 2019-08-20 | Kyocera Corporation | Acoustic wave resonator, acoustic wave filter, multiplexer, and communication apparatus |
CN108496308B (zh) * | 2016-01-29 | 2021-11-16 | 京瓷株式会社 | 弹性波谐振器、弹性波滤波器、分波器及通信装置 |
JP7008633B2 (ja) | 2016-10-13 | 2022-01-25 | 株式会社村田製作所 | 弾性波フィルタ装置 |
WO2018181111A1 (ja) * | 2017-03-30 | 2018-10-04 | 株式会社村田製作所 | マルチプレクサ、高周波フロントエンド回路及び通信装置 |
US11569433B2 (en) | 2017-04-07 | 2023-01-31 | Taiyo Yuden Co., Ltd. | Acoustic wave resonator, filter, and multiplexer |
JPWO2019198594A1 (ja) * | 2018-04-11 | 2021-04-15 | 京セラ株式会社 | 弾性波素子、弾性波フィルタ、分波器および通信装置 |
WO2019198594A1 (ja) * | 2018-04-11 | 2019-10-17 | 京セラ株式会社 | 弾性波素子、弾性波フィルタ、分波器および通信装置 |
JP7433216B2 (ja) | 2018-04-11 | 2024-02-19 | 京セラ株式会社 | 弾性波素子、弾性波フィルタ、分波器および通信装置 |
KR20210031881A (ko) * | 2018-11-08 | 2021-03-23 | 가부시키가이샤 무라타 세이사쿠쇼 | 멀티플렉서 |
KR102546485B1 (ko) | 2018-11-08 | 2023-06-22 | 가부시키가이샤 무라타 세이사쿠쇼 | 멀티플렉서 |
Also Published As
Publication number | Publication date |
---|---|
US9978927B2 (en) | 2018-05-22 |
JPWO2015080278A1 (ja) | 2017-03-16 |
JP2018139445A (ja) | 2018-09-06 |
CN105745840B (zh) | 2018-09-28 |
CN105745840A (zh) | 2016-07-06 |
JP6595342B2 (ja) | 2019-10-23 |
JP6595659B2 (ja) | 2019-10-23 |
US20160380176A1 (en) | 2016-12-29 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6595659B2 (ja) | 弾性波素子、分波器および通信装置 | |
JP6247377B2 (ja) | 弾性波素子、フィルタ素子および通信装置 | |
WO2017188342A1 (ja) | 弾性波素子および通信装置 | |
JP6573668B2 (ja) | 弾性波装置および通信装置 | |
US9124240B2 (en) | Acoustic wave device and antenna duplexer employing the same | |
JP5343965B2 (ja) | 弾性波フィルタ | |
US10097158B2 (en) | Acoustic wave device, filter, and duplexer | |
KR101546248B1 (ko) | 공진기, 필터 및 분파기 | |
JP6487458B2 (ja) | 弾性波素子、フィルタ素子および通信装置 | |
JP5158725B2 (ja) | 弾性表面波装置およびそれを用いた通信装置 | |
JPWO2016121818A1 (ja) | フィルタ,分波器および通信装置 | |
WO2019198594A1 (ja) | 弾性波素子、弾性波フィルタ、分波器および通信装置 | |
WO2019017422A1 (ja) | マルチプレクサ、高周波フロントエンド回路および通信装置 | |
JP4100249B2 (ja) | 弾性表面波装置、通信機 | |
JP2018014715A (ja) | 弾性波素子、フィルタ素子および通信装置 | |
KR101711756B1 (ko) | 탄성파 디바이스, 필터 및 분파기 | |
JP7386741B2 (ja) | フィルタ、分波器及び通信装置 | |
CN108886351B (zh) | 弹性波元件以及通信装置 | |
JP7213747B2 (ja) | 弾性波フィルタ、分波器および通信装置 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 14865460 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2015551033 Country of ref document: JP Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 15039810 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 14865460 Country of ref document: EP Kind code of ref document: A1 |