WO2023248815A1 - Filtre à ondes élastiques et dispositif de communication - Google Patents

Filtre à ondes élastiques et dispositif de communication Download PDF

Info

Publication number
WO2023248815A1
WO2023248815A1 PCT/JP2023/021366 JP2023021366W WO2023248815A1 WO 2023248815 A1 WO2023248815 A1 WO 2023248815A1 JP 2023021366 W JP2023021366 W JP 2023021366W WO 2023248815 A1 WO2023248815 A1 WO 2023248815A1
Authority
WO
WIPO (PCT)
Prior art keywords
elastic wave
resonator
wave resonator
wave filter
band
Prior art date
Application number
PCT/JP2023/021366
Other languages
English (en)
Japanese (ja)
Inventor
直史 笠松
Original Assignee
京セラ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 京セラ株式会社 filed Critical 京セラ株式会社
Publication of WO2023248815A1 publication Critical patent/WO2023248815A1/fr

Links

Images

Classifications

    • 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

Definitions

  • One aspect of the present disclosure relates to an elastic wave filter.
  • Patent Document 1 discloses a configuration example of an elastic wave filter.
  • An elastic wave filter is an elastic wave filter having a first elastic wave resonator, in which the width of the frequency band of the first elastic wave resonator is expressed as ⁇ f, and the elastic wave filter passes through the elastic wave filter.
  • a band extending from a first end point indicating a frequency at the end of the high frequency side of the band to a second end point indicating a frequency higher than the first end point by ⁇ f is referred to as a first band, and the band extends through the passage of the elastic wave filter.
  • a band extending from a third end point indicating a frequency at the end of the low frequency side of the band to a fourth end point indicating a frequency lower by ⁇ f than the third end point is referred to as a second band, and the first elastic wave resonance
  • the child spurious is located outside the frequency band of the first elastic wave resonator and within either the pass band, the first band, or the second band of the elastic wave filter.
  • the elastic wave filter further includes an element connected in parallel or series to the first elastic wave resonator, and the element is a capacitor or an inductor.
  • FIG. 1 is a diagram illustrating the basic configuration of an elastic wave filter of Embodiment 1.
  • FIG. 3 is a diagram showing an example of the configuration of an elastic wave resonator in the elastic wave filter of Embodiment 1.
  • FIG. 2 is a diagram schematically showing an example of frequency characteristics of an elastic wave filter according to one aspect of the present disclosure.
  • FIG. 3 is a diagram schematically showing an example of frequency characteristics of a first elastic wave resonator according to one aspect of the present disclosure.
  • 2 is a diagram showing a first configuration example of an elastic wave filter according to the basic configuration of FIG. 1.
  • FIG. 2 is a diagram showing a second configuration example of an elastic wave filter according to the basic configuration of FIG. 1.
  • FIG. 2 is a diagram showing a third configuration example of an elastic wave filter according to the basic configuration of FIG. 1.
  • FIG. FIG. 3 is a diagram showing a fourth configuration example of an elastic wave filter according to the basic configuration of FIG. 1; It is a figure which shows an example of the phase characteristic and impedance characteristic of the 1st elastic wave resonator in the elastic wave filter based on the 1st example of a structure. It is a figure which shows an example of the phase characteristic and impedance characteristic of the 1st elastic wave resonator in the elastic wave filter based on the 2nd example of a structure.
  • FIG. 7 is a diagram showing another example of the phase characteristics and impedance characteristics of the first elastic wave resonator in the elastic wave filter according to the first configuration example.
  • FIG. 3 is a diagram for explaining a change in phase characteristics of a first elastic wave resonator in an elastic wave filter according to a first configuration example.
  • FIG. 7 is a diagram for explaining a change in phase characteristics of a first elastic wave resonator in an elastic wave filter according to a second configuration example.
  • FIG. 7 is a diagram for explaining a change in phase characteristics of the first elastic wave resonator according to a third configuration example. It is a figure for explaining the change of the phase characteristic of the 1st elastic wave resonator concerning the 4th example of composition.
  • 3 is a diagram illustrating a schematic configuration of a communication device in Embodiment 2.
  • Embodiment 1 will be described below.
  • components having the same functions as the components (components) described in Embodiment 1 are given the same reference numerals in each of the subsequent embodiments, and the description thereof will not be repeated.
  • descriptions of known technical matters will be omitted as appropriate.
  • Each component, each material, and each numerical value described in this specification is merely an example unless there is a contradiction. Therefore, for example, unless there is a particular contradiction, the positional relationship and connection relationship of each component is not limited to the example shown in each figure. Further, each figure is not necessarily shown to scale.
  • FIG. 1 illustrates the basic configuration of an elastic wave filter 100 according to a first embodiment.
  • an elastic wave filter 100 as a ladder type filter is illustrated.
  • the elastic wave filter according to one aspect of the present disclosure is not limited to the ladder type filter.
  • the elastic wave filter 100 may have at least one elastic wave resonator including a first elastic wave resonator. Therefore, for example, the elastic wave filter 100 may include a plurality of elastic wave resonators. In other words, the elastic wave filter 100 may further include a second elastic wave resonator different from the first elastic wave resonator. In the example of FIG. 1, the elastic wave filter 100 has three elastic wave resonators 1.
  • the elastic wave filter 100 may include, as the elastic wave resonator 1, an elastic wave resonator (series resonator) located in the series arm SL.
  • the elastic wave filter 100 includes a series resonator 1S-1 and a series resonator 1S-2.
  • the series resonator 1S-1 and the series resonator 1S-2 are also generically referred to as the series resonator 1S.
  • the series arm SL may be connected to the input terminal Pin and the output terminal Pout.
  • the series resonator 1S-1 is the series resonator on the side closer to the input terminal Pin (the series resonator on the input side)
  • the series resonator 1S-2 is the series resonator on the side closer to the output terminal Pout. (series resonator on the output side).
  • the elastic wave filter 100 may include, as the elastic wave resonator 1, an elastic wave resonator (parallel resonator) located in the parallel arm PL.
  • the elastic wave filter 100 has a parallel resonator 1P.
  • the parallel arm PL may extend from between the series resonator 1S-1 and the series resonator 1S-2, and may be connected to the ground terminal GND via the parallel resonator 1P.
  • the series resonator 1S-1 is the first elastic wave resonator.
  • the first elastic wave resonator may be any one of the at least one elastic wave resonator 1 included in the elastic wave filter 100. Therefore, as described later, the parallel resonator 1P may be the first elastic wave resonator.
  • the elastic wave filter 100 may further include an element EL connected in parallel or series to the first elastic wave resonator.
  • element EL is connected in parallel to series resonator 1S-1.
  • element EL may be a capacitor or an inductor.
  • element EL may be embodied by a discrete component.
  • the element EL may be realized by electrode wiring on the piezoelectric layer 2 described below.
  • the acoustic wave filter 100 may have a multilayer substrate including a dielectric layer and a conductor layer. In this case, the element EL may be embodied by an electrode pattern within the multilayer substrate.
  • FIG. 2 shows an example of the configuration of the elastic wave resonator 1 in the elastic wave filter 100.
  • the laminated structure of the elastic wave resonator 1 is schematically shown.
  • the orthogonal coordinate system (xyz coordinate system) shown in FIG. 2 will be introduced.
  • the x direction in the example of the first embodiment is the propagation direction of the elastic wave propagating within the piezoelectric layer 2 in the elastic wave filter 100.
  • the y direction is an example of a direction intersecting the x direction.
  • the z direction is the thickness direction of each member of the elastic wave resonator 1.
  • the positive direction in the z direction is assumed to be an upward direction. Therefore, the negative direction in the z direction is downward.
  • the elastic wave filter 100 may include (i) a support substrate 5 and (ii) a piezoelectric layer 2 located on the support substrate 5.
  • the support substrate 5 and the piezoelectric layer 2 may be common to at least one elastic wave resonator 1.
  • the elastic wave resonator 1 may include an IDT (Interdigital Transduce) electrode 3 located on the piezoelectric layer 2 .
  • Each of the at least one acoustic wave resonator 1 may have an individual IDT electrode 3 .
  • the support substrate 5 supports each part of the acoustic wave filter 100.
  • the support substrate 5 may be a Si substrate.
  • the piezoelectric layer 2 may be made of a single crystal material having piezoelectricity.
  • the material of the piezoelectric layer 2 may be lithium tantalate (also referred to as LiTaO 3 :LT) or lithium niobate (also referred to as LiNbO 3 :LN).
  • the piezoelectric layer 2 may be an LT layer.
  • the IDT electrode 3 may include, for example, a conductive layer made of metal.
  • the metal may be Al.
  • the IDT electrode 3 may further include a protective layer covering the conductive layer.
  • the material of the protective layer may be TEOS (Tetraethyl Orthosilicate).
  • the IDT electrode 3 may include a first bus bar and a second bus bar (not shown) that face each other in the y direction.
  • the IDT electrode 3 includes (i) a plurality of first electrode fingers 32a connected to the first bus bar, and (ii) a plurality of second electrode fingers 32b connected to the second bus bar. good.
  • the first electrode finger 32a may extend from the first bus bar toward the second bus bar in the y direction.
  • the second electrode finger 32b may extend from the second bus bar toward the first bus bar in the y direction. Therefore, the second electrode finger 32b may be inserted into each of the plurality of first electrode fingers 32a in the y direction.
  • the first electrode fingers 32a and the second electrode fingers 32b may be alternately and repeatedly positioned on the piezoelectric layer 2 at approximately constant intervals in the x direction.
  • the first electrode finger 32a and the second electrode finger 32b are also generically referred to as electrode fingers 32.
  • the electrode finger pitch of the IDT electrode 3 is expressed as p.
  • p may be, for example, the pitch (repetition interval) between the centers of two adjacent electrode fingers 32 in the x direction.
  • p may be set equal to the half value ( ⁇ /2) of the wavelength ⁇ of the elastic wave excited by the IDT electrode 3.
  • the length of the electrode finger 32 in the x direction is referred to as the width w of the electrode finger 32.
  • w may be set as appropriate, for example, depending on the electrical characteristics required of the elastic wave resonator 1.
  • w may be set according to p.
  • the ratio (w/p) of the width of the electrode finger to the pitch of the electrode finger is referred to as the duty of the electrode finger.
  • the frequency characteristics of the elastic wave resonator 1 can also be controlled by changing either w or p. In this specification, a case will be illustrated later in which the frequency characteristics of the elastic wave resonator 1 are controlled by changing p.
  • the thickness of the piezoelectric layer 2 is expressed as T.
  • Embodiment 1 exemplifies a case where the piezoelectric layer 2 is sufficiently thin, that is, a case where T is sufficiently small.
  • T may be less than or equal to ⁇ .
  • the IDT electrode 3 can excite plate waves (Lamb waves) as elastic waves.
  • the IDT electrode 3 can excite an A1 Lamb wave as a plate wave.
  • FIG. 3 schematically shows an example of frequency characteristics (more specifically, attenuation characteristics) of an elastic wave filter (eg, elastic wave filter 100) according to one aspect of the present disclosure.
  • the horizontal axis (Frequency) indicates frequency (unit: Hz)
  • the vertical axis (transmission) indicates attenuation (unit: dB).
  • the amount of attenuation can also be read as the amount of transmission. Therefore, the attenuation characteristic can also be read as the transmission characteristic.
  • the passband of an elastic wave filter refers to a frequency band from a low frequency side cutoff frequency to a high frequency side cutoff frequency.
  • the attenuation characteristic of the elastic wave filter 100 there are -3 dB attenuation points on each of the low frequency side and the high frequency side with respect to the peak frequency indicating the frequency at the minimum attenuation amount of 0 dB.
  • the high frequency side cutoff frequency (fcut1 in FIG. 3) is the frequency of the ⁇ 3 dB attenuation point on the high frequency side of the passband of the elastic wave filter.
  • fcut1 can also be expressed as the frequency at the end of the high frequency side of the passband.
  • the low frequency side cutoff frequency (fcut2 in FIG. 3) is the frequency of the ⁇ 3 dB attenuation point on the low frequency side.
  • fcut2 can also be expressed as the frequency at the lower frequency side end of the passband. Therefore, the passband of the elastic wave filter is a band extending from fcut2 to fcut1.
  • the width of the frequency band of the first elastic wave resonator is expressed as ⁇ f.
  • ⁇ f the band extending from the first end point to the second end point.
  • the first end point may be a point indicating the frequency at the end of the high frequency side of the passband of the elastic wave filter (ie, fcut1).
  • the second end point may point to a frequency that is + ⁇ f higher than the first starting point (ie, fcut1+ ⁇ f).
  • the band from the third end point to the fourth end point is referred to as a second band.
  • the third end point may be a point indicating the frequency at the lower frequency side end of the passband of the elastic wave filter (ie, fcut2).
  • the fourth endpoint may be a point pointing to a frequency that is ⁇ f lower than the third endpoint (ie, fcut2 ⁇ f).
  • the spurious of the first elastic wave resonator is located within a band extending from the fourth end point (fcut2- ⁇ f) to the second end point (fcut1+ ⁇ f). I can do it.
  • the spurious of the first elastic wave resonator may be located within the pass band, within the first band, or within the second band of the elastic wave filter.
  • FIG. 4 schematically shows an example of frequency characteristics (more specifically, phase characteristics) of the first elastic wave resonator according to one aspect of the present disclosure.
  • the vertical axis (Phase) in the graph of FIG. 4 represents the phase (hereinafter simply referred to as "phase") of the impedance of the first elastic wave resonator (unit: degrees).
  • FIG. 4 shows the phase characteristics of the first elastic wave resonator before being connected to the element EL (that is, the phase characteristics of the first elastic wave resonator alone).
  • fr is the resonant frequency of the first elastic wave resonator
  • fa is the anti-resonant frequency of the first elastic wave resonator.
  • the frequency band of the first elastic wave resonator may range from fr to fa.
  • fr ⁇ fa is illustrated.
  • the frequency band of the first elastic wave resonator is located on the lower frequency side than the above-mentioned second band.
  • the magnitude (absolute value) of the impedance of the first elastic wave resonator is expressed as
  • fr is defined as the frequency at which the impedance is minimum.
  • fa is determined as the frequency at which the impedance is maximum.
  • the phase peak of the first elastic wave resonator is generally located within the frequency band of the first elastic wave resonator.
  • the spurious of the first elastic wave resonator is generally located outside the frequency band of the first elastic wave resonator.
  • the spurious of the first elastic wave resonator can be located within the pass band, the first band, or the second band of the elastic wave filter. In the example of FIG. 4, the spurious of the first elastic wave resonator is located within the passband of the elastic wave filter.
  • FIG. 5 shows a first configuration example of an elastic wave filter according to the basic configuration of FIG.
  • the elastic wave filter shown in FIG. 5 is referred to as an elastic wave filter 100-1.
  • the first elastic wave resonator in the elastic wave filter 100-1 may be a series resonator (eg, series resonator 1S-1).
  • the elastic wave filter 100-1 may include a capacitor CP connected in parallel to the first elastic wave resonator (eg, series resonator 1S-1) as an element EL. Therefore, the elastic wave filter 100-1 may include a first unit UN1 configured by connecting a series resonator, which is a first elastic wave resonator, and a capacitor CP in parallel. As will be described later, in the elastic wave filter 100-1, the spurious of the first elastic wave resonator may be located within the first band.
  • FIG. 6 shows a second configuration example of an elastic wave filter according to the basic configuration of FIG. 1.
  • the elastic wave filter shown in FIG. 6 is referred to as an elastic wave filter 100-2.
  • the first elastic wave resonator may be a series resonator (eg, series resonator 1S-1).
  • the elastic wave filter 100-2 may include an inductor LP connected in parallel to the first elastic wave resonator (eg, series resonator 1S-1) as an element EL. Therefore, the elastic wave filter 100-2 may include a second unit UN2 configured by connecting a series resonator, which is a first elastic wave resonator, and an inductor LP in parallel. Elastic wave filter 100-2 is another configuration example of elastic wave filter 100-1. As described later, in the elastic wave filter 100-2, the spurious of the first elastic wave resonator may be located within the second band.
  • FIG. 7 shows a third configuration example of an elastic wave filter according to the basic configuration of FIG. 1.
  • the elastic wave filter shown in FIG. 7 is referred to as an elastic wave filter 100-3.
  • the first elastic wave resonator in the elastic wave filter 100-3 may be a parallel resonator (eg, parallel resonator 1P).
  • the elastic wave filter 100-3 may have an inductor LS connected in series to the first elastic wave resonator (eg, parallel resonator 1P) as an element EL. Therefore, the elastic wave filter 100-3 may include a third unit UN3 configured by connecting a parallel resonator, which is a first elastic wave resonator, and an inductor LS in series. As described later, in the elastic wave filter 100-3, the spurious of the first elastic wave resonator may be located within the first band.
  • FIG. 8 shows a fourth configuration example of an elastic wave filter according to the basic configuration of FIG. 1.
  • the elastic wave filter shown in FIG. 8 is referred to as an elastic wave filter 100-4.
  • the first elastic wave resonator may be a parallel resonator (eg, parallel resonator 1P).
  • the elastic wave filter 100-4 may have a capacitor CS connected in series to the first elastic wave resonator (eg, parallel resonator 1P) as an element EL. Therefore, the elastic wave filter 100-4 may include a fourth unit UN4 configured by connecting a parallel resonator, which is a first elastic wave resonator, and a capacitor CS in series. Elastic wave filter 100-4 is another configuration example of elastic wave filter 100-3. As will be described later, in the elastic wave filter 100-4, the spurious of the first elastic wave resonator may be located within the second band.
  • the design conditions for the first elastic wave resonator are: ⁇ p (electrode finger pitch of IDT electrode): 1.26 ⁇ m ⁇ Duty of IDT electrode: 0.7 ⁇ Number of electrode fingers of IDT electrode: 150 ⁇ Intersection width of electrode fingers of IDT electrode: 61.2 ⁇ m It is. However, in the example of FIG. 13 described later, different design conditions may be applied.
  • the horizontal axis of each graph shown below indicates the normalized frequency fn. fn is given as the frequency f divided by fa. Therefore, the horizontal axis of each graph shown below may be read as f.
  • the frequency characteristics shown below are the frequency characteristics of the first elastic wave resonator in a state connected to the element EL in the elastic wave filter. That is, it should be noted that the frequency characteristics shown below are not the frequency characteristics of the first elastic wave resonator in a state before being connected to the element EL (the frequency characteristics of the first elastic wave resonator alone). Therefore, fr and fa in each of the following descriptions are the resonant frequency and anti-resonant frequency of the first elastic wave resonator in a state connected to the element EL, respectively, unless otherwise specified.
  • FIG. 9 shows an example of the phase characteristics and impedance characteristics of the first elastic wave resonator in the elastic wave filter 100-1.
  • reference numeral 900A indicates the phase characteristic of the first elastic wave resonator in the elastic wave filter 100-1
  • reference numeral 900B indicates the impedance characteristic of the first elastic wave resonator.
  • the capacitance of the capacitor CP is also expressed as CP.
  • characteristics corresponding to various values of CP are shown.
  • FIG. 10 shows an example of the phase characteristics and impedance characteristics of the first elastic wave resonator in the elastic wave filter 100-2.
  • the reference numeral 1000A indicates the phase characteristic of the first elastic wave resonator in the elastic wave filter 100-2
  • the reference numeral 1000B indicates the impedance characteristic of the first elastic wave resonator.
  • the inductance of the inductor LP is also expressed as LP.
  • each characteristic corresponding to various values of LP is shown.
  • FIG. 11 shows an example of the phase characteristics and impedance characteristics of the first elastic wave resonator in the elastic wave filter 100-3.
  • reference numeral 1100A indicates the phase characteristic of the first elastic wave resonator in the elastic wave filter 100-3
  • reference numeral 1100B indicates the impedance characteristic of the first elastic wave resonator.
  • the inductance of the inductor LS is also expressed as LS.
  • characteristics corresponding to various values of LS are shown.
  • FIG. 12 shows an example of the phase characteristics and impedance characteristics of the first elastic wave resonator in the elastic wave filter 100-4.
  • reference numeral 1200A indicates the phase characteristic of the first elastic wave resonator in the elastic wave filter 100-4
  • reference numeral 1200B indicates the impedance characteristic of the first elastic wave resonator.
  • the capacitance of the capacitor CS is also expressed as CS.
  • the frequency characteristics of the first elastic wave resonator in the elastic wave filter depend on (i) the type of element EL connected to the first elastic wave resonator, and (ii) the first elastic wave It may change depending on at least one of the connection manner between the resonator and the element EL. Therefore, for example, the first elastic wave resonator connected to the element EL may be redesigned according to the required specifications of the elastic wave filter.
  • FIG. 13 an example of redesigning the first elastic wave resonator will be described.
  • FIG. 13 shows another example of the phase characteristics and impedance characteristics of the first elastic wave resonator in the elastic wave filter 100-1.
  • reference numeral 1300A is a diagram paired with the above-mentioned reference numeral 900A
  • reference numeral 1300B is a diagram paired with the above-mentioned reference numeral 900B.
  • the legend "c2" in FIG. 13 represents a redesign that increases the capacitance of the first elastic wave resonator by 0.6 times.
  • the number of electrode fingers of the IDT electrode in the first acoustic wave resonator from 150 to 90, it is possible to redesign the capacitance of the first acoustic wave resonator to increase it by 0.6. being done.
  • the legend "p2" in FIG. 13 represents a redesign in which the electrode finger pitch (p) of the IDT electrode in the first acoustic wave resonator is changed from 1.26 ⁇ m to 1.215 ⁇ m. In this redesign, p is multiplied by about 0.964.
  • FIG. 13 shows that the magnitude of spurious can be reduced by redesigning the first acoustic wave resonator to reduce its capacitance.
  • the elastic wave filter 100-1 a part of the capacitance value of the first elastic wave resonator before redesign can be compensated for by the capacitor CP. Therefore, according to the elastic wave filter 100-1, such redesign can be applied. As is clear to those skilled in the art, such redesign can also be applied to the elastic wave filter 100-4.
  • the first elastic wave resonator may be a series resonator or a parallel resonator
  • the element EL may be a capacitor connected in series or in parallel to the first elastic wave resonator. It's fine.
  • FIG. 13 further shows that the frequency characteristics of the first acoustic wave resonator can be generally shifted by redesigning to change p. For example, fa and fr can be increased by redesigning p to be smaller. Conversely, fa and fr can also be decreased by redesigning to increase p.
  • FIG. 14 is a diagram for explaining changes in the phase characteristics of the series resonator, which is the first elastic wave resonator, in the elastic wave filter 100-1.
  • Reference numeral 1400A in FIG. 14 shows the phase characteristics of the first elastic wave resonator before connecting the capacitor CP (the phase characteristics of the first elastic wave resonator alone), and the phase characteristics of the first elastic wave resonator after connecting the capacitor CP. is shown schematically.
  • Reference numeral 1400B in FIG. 14 schematically shows the phase characteristics of the redesigned first acoustic wave resonator after the capacitor CP is connected.
  • the spurious of the first elastic wave resonator is located within the passband of the elastic wave filter both before and after the capacitor CP is connected. Specifically, the spurious of the first elastic wave resonator is located near the above-mentioned first end point within the passband of the elastic wave filter.
  • fa before the element EL is connected will be expressed as fa0.
  • fa0 in the example of FIG. 14 indicates fa before the capacitor CP is connected.
  • fa after connecting the capacitor CP in the example 1400A is expressed as fa_cp.
  • fa of the redesigned first acoustic wave resonator after connecting the capacitor CP is expressed as fa_cp'.
  • the first elastic wave resonator may be redesigned so that fa_cp' matches fa0. In this case, due to the redesign of the first acoustic wave resonator, fa_cp' becomes higher than fa_cp.
  • the frequency characteristics of the first elastic wave resonator can be shifted to the high frequency side. Therefore, compared to the example with reference numeral 1400A, the spurious of the first elastic wave resonator can be shifted to the higher frequency side. Therefore, as shown in the example at 1400B, the spurious of the first acoustic wave resonator can be located within the first band.
  • the first elastic wave resonator in the elastic wave filter is a series resonator and the element EL is a capacitor connected in parallel to the first elastic wave resonator
  • the spurious of one acoustic wave resonator may be located within the first band.
  • FIG. 15 is a diagram for explaining changes in the phase characteristics of the series resonator, which is the first elastic wave resonator, in the elastic wave filter 100-2.
  • Reference numeral 1500A in FIG. 15 shows the phase characteristics of the first elastic wave resonator before the inductor LP is connected (the phase characteristics of the first elastic wave resonator alone), and the phase characteristics of the first elastic wave resonator after the inductor LP is connected. is shown schematically.
  • Reference numeral 1500B in FIG. 15 schematically shows the phase characteristics of the redesigned first acoustic wave resonator after the inductor LP is connected.
  • the spurious of the first elastic wave resonator is located within the passband of the elastic wave filter both before and after the inductor LP is connected. Specifically, the spurious of the first elastic wave resonator is located near the above-mentioned third end point within the passband of the elastic wave filter.
  • the magnitude of the spurious of the first acoustic wave resonator may increase compared to before the inductor LP is connected. This behavior is due to the duality between the frequency characteristics of the inductor and the frequency characteristics of the capacitor. Furthermore, as described above, after the inductor LP is connected, fa can increase compared to before the inductor LP is connected.
  • fa0 in the example of FIG. 15 indicates fa before the inductor LP is connected.
  • fa after the inductor LP is connected in the example of code 1500A is expressed as fa_lp.
  • fa of the redesigned first acoustic wave resonator after the inductor LP is connected is expressed as fa_lp'.
  • the first elastic wave resonator may be redesigned so that fa_lp' matches fa0. In this case, due to the redesign of the first acoustic wave resonator, fa_lp' becomes lower than fa_lp.
  • the frequency characteristics of the first elastic wave resonator can be shifted to the lower frequency side. Therefore, compared to the example with reference numeral 1500A, the spurious of the first elastic wave resonator can be shifted to the lower frequency side. Therefore, as shown in the example at 1500B, the spurious of the first acoustic wave resonator can be located within the second band.
  • the first elastic wave resonator in the elastic wave filter is a series resonator and the element EL is an inductor connected in parallel to the first elastic wave resonator
  • the spurious of one acoustic wave resonator may be located within the second band.
  • FIG. 16 is a diagram for explaining changes in the phase characteristics of the parallel resonator, which is the first elastic wave resonator, in the elastic wave filter 100-3.
  • Reference numeral 1600A in FIG. 16 indicates the phase characteristics of the first elastic wave resonator before the inductor LS is connected (the phase characteristics of the first elastic wave resonator alone), and the phase characteristics of the first elastic wave resonator after the inductor LS is connected. is shown schematically.
  • Reference numeral 1600B in FIG. 16 schematically shows the phase characteristics of the redesigned first acoustic wave resonator after the inductor LS is connected.
  • the spurious of the first elastic wave resonator is located within the passband of the elastic wave filter both before and after the inductor LS is connected. Specifically, the spurious of the first elastic wave resonator is located near the first end point within the passband of the elastic wave filter.
  • fr before the element EL is connected will be expressed as fr0.
  • fr0 in the example of FIG. 16 indicates fr before the inductor LS is connected.
  • fr after the inductor LS is connected in the example 1600A is written as fr_ls.
  • fr of the redesigned first acoustic wave resonator after the inductor LS is connected is expressed as fr_ls'.
  • fr_ls can become lower than fr0 due to the connection of the inductor LS. Therefore, as an example, the first elastic wave resonator may be redesigned so that fr_ls' matches fr0. In this case, fr_ls' becomes higher than fr_ls due to the redesign of the first elastic wave resonator.
  • the frequency characteristics of the first elastic wave resonator can be shifted to the high frequency side. Therefore, compared to the example with reference numeral 1600A, the spurious of the first elastic wave resonator can be shifted to the higher frequency side. Therefore, as shown in the example at 1600B, the spurious of the first acoustic wave resonator can be located within the first band.
  • the first elastic wave resonator in the elastic wave filter is a parallel resonator and the element EL is an inductor connected in series with the first elastic wave resonator
  • the spurious of one acoustic wave resonator may be located within the first band.
  • FIG. 17 is a diagram for explaining changes in the phase characteristics of the parallel resonator, which is the first elastic wave resonator, in the elastic wave filter 100-4.
  • Reference numeral 1700A in FIG. 17 shows the phase characteristics of the first elastic wave resonator before connecting the capacitor CS (the phase characteristics of the first elastic wave resonator alone), and the phase characteristics of the first elastic wave resonator after connecting the capacitor CS. is shown schematically.
  • Reference numeral 1700B in FIG. 17 schematically shows the phase characteristics of the redesigned first acoustic wave resonator after connecting the capacitor CS.
  • the spurious of the first elastic wave resonator is located within the passband of the elastic wave filter both before and after the capacitor CS is connected. Specifically, the spurious of the first elastic wave resonator is located near the third end point within the passband of the elastic wave filter.
  • fr may increase compared to before connecting the capacitor CS.
  • fr_cs fr after the capacitor CS is connected in the example of 1700A is expressed as fr_cs.
  • fr of the redesigned first acoustic wave resonator after connecting the capacitor CS is expressed as fr_cs'.
  • fr_cs can become higher than fr0 due to the connection of the capacitor CS. Therefore, as an example, the first elastic wave resonator may be redesigned so that fr_cs' matches fr0. In this case, fr_cs' becomes lower than fr_cs due to the redesign of the first elastic wave resonator.
  • the frequency characteristics of the first elastic wave resonator can be shifted to the lower frequency side. Therefore, compared to the example with reference numeral 1700A, the spurious of the first elastic wave resonator can be shifted to the lower frequency side. Therefore, as shown in the example at 1700B, the spurious of the first acoustic wave resonator can be located within the second band.
  • the first elastic wave resonator in the elastic wave filter is a parallel resonator and the element EL is a capacitor connected in series to the first elastic wave resonator
  • the spurious of one acoustic wave resonator may be located within the second band.
  • the first elastic wave resonator in the elastic wave filter may be connected in parallel or in series with the element EL.
  • Element EL may then be a capacitor or an inductor.
  • the spurious of the first elastic wave resonator can be located within the pass band, the first band, or the second band of the elastic wave filter. Moreover, the spurious of the first elastic wave resonator can also be located outside the frequency band of the first elastic wave resonator.
  • the passband of the elastic wave filter may be located between the resonant frequency of the first elastic wave resonator and the spurious of the first elastic wave resonator (e.g., see reference numeral 1600B in FIG. 16).
  • the passband of the elastic wave filter may be located between the anti-resonance frequency of the first elastic wave resonator and the spurious of the first elastic wave resonator (see e.g. 1400B in FIG. 14). ).
  • the passband of the elastic wave filter does not need to include either the resonant frequency or the anti-resonant frequency of the first elastic wave resonator (for example, see reference numeral 1400B in FIG. 14). ).
  • the passband of the elastic wave filter is located on the higher frequency side than the frequency band of the first elastic wave resonator.
  • the passband of the elastic wave filter may be located on the lower frequency side than the frequency band of the first elastic wave resonator. Therefore, for example, the spurious of the first elastic wave resonator may also be located on the lower frequency side than the frequency band of the first elastic wave resonator.
  • the elastic wave filter according to one aspect of the present disclosure may further include a second elastic wave resonator different from the first elastic wave resonator.
  • the elastic wave filter does not need to have an element (eg, a capacitor or an inductor) connected in parallel or in series with the second elastic wave resonator. Therefore, as an example, the second elastic wave resonator may be any one of the two elastic wave resonators other than the first elastic wave resonator (e.g., series resonance child 1S-2).
  • the second elastic wave resonator may be designed so that the spurious of the second elastic wave resonator does not overlap with the spurious of the first elastic wave resonator. Therefore, for example, the second elastic wave resonator is designed so that the spurious of the second elastic wave resonator is not located within the pass band, the first band, or the second band of the elastic wave filter. It's okay to be.
  • the first elastic wave resonator may be designed to have a higher anti-resonance frequency than the second elastic wave resonator. From this, for example, the first elastic wave resonator may be designed to have the highest anti-resonance frequency among the plurality of elastic wave resonators in the elastic wave filter.
  • ⁇ f the first (the width of the frequency band of the elastic wave resonator) may be reduced. Therefore, in this case, ⁇ f may be smaller than the average value of the frequency band widths of the plurality of elastic wave resonators.
  • ⁇ f when the element EL connected in parallel or series to the first acoustic wave resonator is an inductor, the ⁇ f may increase. Therefore, in this case, ⁇ f can be larger than the average value of the frequency band widths of the plurality of elastic wave resonators.
  • FIG. 18 illustrates a schematic configuration of a communication device 151 in the second embodiment.
  • the communication device 151 is an application example of an elastic wave filter according to one aspect of the present disclosure, and performs wireless communication using radio waves.
  • the communication device 151 may include one duplexer 101 as a transmission filter 109 and another duplexer 101 as a reception filter 111.
  • Each of the two duplexers 101 may include an elastic wave filter according to one aspect of the present disclosure.
  • the communication device 151 may include an elastic wave filter according to one aspect of the present disclosure.
  • a transmission information signal TIS containing information to be transmitted is modulated and frequency-increased (converted to a high-frequency signal having a carrier frequency) by an RF-IC (Radio Frequency-Integrated Circuit) 153, and the transmission information signal TIS is converted into a transmission signal. It may be converted to TS.
  • the bandpass filter 155 may remove unnecessary components other than the transmission passband for the TS.
  • the TS after removing unnecessary components may be amplified by the amplifier 157 and input to the transmission filter 109.
  • the transmission filter 109 may remove unnecessary components outside the transmission passband from the input transmission signal TS.
  • the transmission filter 109 may output the TS from which unnecessary components have been removed to the antenna 159 via an antenna terminal (eg, TCin described above).
  • the antenna 159 may convert the TS, which is an electrical signal input to itself, into a radio wave as a wireless signal, and transmit the radio wave to the outside of the communication device 151.
  • the antenna 159 may convert the received radio waves from the outside into a reception signal RS, which is an electrical signal, and input the RS to the reception filter 111 via the antenna terminal.
  • the reception filter 111 may remove unnecessary components other than the reception passband from the input RS.
  • the reception filter 111 may output the reception signal RS from which unnecessary components have been removed to the amplifier 161.
  • the output RS may be amplified by the amplifier 161.
  • the bandpass filter 163 may remove unnecessary components other than the receiving passband from the amplified RS.
  • the frequency of the RS after unnecessary component removal is lowered and demodulated by the RF-IC 153, and may be converted into a received information signal RIS.
  • An elastic wave filter according to aspect 1 of the present disclosure is an elastic wave filter having a first elastic wave resonator, in which the width of the frequency band of the first elastic wave resonator is expressed as ⁇ f, and the elastic wave filter passes through the elastic wave filter.
  • a band extending from a first end point indicating a frequency at the end of the high frequency side of the band to a second end point indicating a frequency higher than the first end point by ⁇ f is referred to as a first band, and the band extends through the passage of the elastic wave filter.
  • a band extending from a third end point indicating a frequency at the end of the low frequency side of the band to a fourth end point indicating a frequency lower by ⁇ f than the third end point is referred to as a second band, and the first elastic wave resonance
  • the child spurious is located outside the frequency band of the first elastic wave resonator and within either the pass band, the first band, or the second band of the elastic wave filter.
  • the elastic wave filter further includes an element connected in parallel or series to the first elastic wave resonator, and the element is a capacitor or an inductor.
  • the first elastic wave resonator is a series resonator, the spurious is located within the first band, and the element is , may be a capacitor connected in parallel to the first acoustic wave resonator.
  • the first elastic wave resonator is a parallel resonator
  • the spurious is located within the first band
  • the element is , may be an inductor connected in series with the first elastic wave resonator.
  • the first elastic wave resonator is a parallel resonator
  • the spurious is located within the second band
  • the element is , may be a capacitor connected in series to the first elastic wave resonator.
  • the first elastic wave resonator is a series resonator or a parallel resonator, and the spurious is within the passband of the elastic wave filter. and the element may be a capacitor connected in series or in parallel to the first acoustic wave resonator.
  • the elastic wave filter according to aspect 7 of the present disclosure is the same as in aspect 1, further comprising a second elastic wave resonator different from the first elastic wave resonator, and the spurious of the second elastic wave resonator is , which is not located within the passband, the first band, or the second band of the elastic wave filter, and is connected in parallel or series to the second elastic wave resonator. It may not have a capacitor or inductor.
  • An elastic wave filter according to an aspect 8 of the present disclosure in the aspect 1, includes a plurality of elastic wave resonators including the first elastic wave resonator, the element is a capacitor, and ⁇ f is a plurality of elastic wave resonators. may be smaller than the average width of the frequency band in the elastic wave resonator.
  • the elastic wave filter according to aspect 9 of the present disclosure is the same as in aspect 1, and includes a plurality of elastic wave resonators including the first elastic wave resonator, the element is an inductor, and ⁇ f is a plurality of elastic wave resonators. may be larger than the average width of the frequency band in the elastic wave resonator.
  • the elastic wave filter according to aspect 10 of the present disclosure in any one of aspects 1 to 9, includes a plurality of elastic wave resonators including the first elastic wave resonator, and the elastic wave filter includes a plurality of elastic wave resonators including the first elastic wave resonator, and The resonator may have the highest anti-resonance frequency among the plurality of elastic wave resonators.
  • the passband of the elastic wave filter includes (i) the resonance frequency of the first elastic wave resonator and the spurious or (ii) between the anti-resonance frequency of the first elastic wave resonator and the spurious.
  • a communication device may include the elastic wave filter according to any one of aspects 1 to 13.

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

Dans la présente invention, les caractéristiques de fréquence d'un filtre à ondes élastiques sont améliorées. Ce filtre à ondes élastiques a un premier résonateur à ondes élastiques. La largeur de la bande de fréquences du premier résonateur à ondes élastiques est représentée par Δf, une bande allant d'un premier point d'extrémité indiquant la fréquence à l'extrémité haute fréquence d'une bande passante du filtre à ondes élastiques à un deuxième point d'extrémité indiquant une fréquence exactement Δf supérieure au premier point d'extrémité est appelée première bande, et une bande allant d'un troisième point d'extrémité indiquant la fréquence à l'extrémité basse fréquence de la bande passante du filtre à ondes élastiques à un quatrième point d'extrémité indiquant une fréquence exactement Δf inférieure au troisième point d'extrémité est appelée deuxième bande. Les parasites du premier résonateur à ondes élastiques sont situés à l'extérieur de la bande de fréquences du premier résonateur à ondes élastiques et sont situés soit dans la bande passante du filtre à ondes élastiques, dans la première bande, soit dans la deuxième bande. Le filtre à ondes élastiques comprend en outre un élément connecté en parallèle ou en série au premier résonateur à ondes élastiques. L'élément est un condensateur ou un inducteur.
PCT/JP2023/021366 2022-06-22 2023-06-08 Filtre à ondes élastiques et dispositif de communication WO2023248815A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022-100435 2022-06-22
JP2022100435 2022-06-22

Publications (1)

Publication Number Publication Date
WO2023248815A1 true WO2023248815A1 (fr) 2023-12-28

Family

ID=89379738

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/021366 WO2023248815A1 (fr) 2022-06-22 2023-06-08 Filtre à ondes élastiques et dispositif de communication

Country Status (1)

Country Link
WO (1) WO2023248815A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011040817A (ja) * 2009-08-06 2011-02-24 Taiyo Yuden Co Ltd 分波器
WO2016190216A1 (fr) * 2015-05-22 2016-12-01 京セラ株式会社 Dispositif à ondes élastiques et dispositif de communication
WO2021079830A1 (fr) * 2019-10-24 2021-04-29 京セラ株式会社 Dispositif à ondes élastiques

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011040817A (ja) * 2009-08-06 2011-02-24 Taiyo Yuden Co Ltd 分波器
WO2016190216A1 (fr) * 2015-05-22 2016-12-01 京セラ株式会社 Dispositif à ondes élastiques et dispositif de communication
WO2021079830A1 (fr) * 2019-10-24 2021-04-29 京セラ株式会社 Dispositif à ondes élastiques

Similar Documents

Publication Publication Date Title
KR100434609B1 (ko) 탄성표면파 필터장치
US8125298B2 (en) Acoustic wave filter, duplexer using the acoustic wave filter, and communication apparatus using the duplexer
US9762209B2 (en) Duplexer with a series trap element and a specifically connected capacitance or elastic wave resonator
KR100797833B1 (ko) 탄성 표면파 필터 및 그를 이용한 안테나 공용기
JP4640502B2 (ja) Ｓａｗフィルタ装置
JP6637990B2 (ja) 弾性波共振子、弾性波フィルタ、分波器、通信装置および弾性波共振子の設計方法
US7212086B2 (en) Surface acoustic wave device
KR100688885B1 (ko) 탄성 표면파 필터, 분파기, 통신기
US7868716B2 (en) Acoustic wave filter apparatus
US10958241B2 (en) Extractor
WO2013154113A1 (fr) Filtre à ondes acoustiques de surface de type échelle
JP3528049B2 (ja) 弾性表面波装置、通信装置
EP1005153B1 (fr) Filtre à ondes acoustiques de surface
WO2010061496A1 (fr) Dispositif de filtre d’onde élastique
JPH0856135A (ja) 弾性表面波装置
CN114301422A (zh) 滤波器、多工器、射频前端及制造滤波器的方法
JPWO2006040923A1 (ja) 分波器
JP7386741B2 (ja) フィルタ、分波器及び通信装置
US7746199B2 (en) Acoustic wave device
WO2023248815A1 (fr) Filtre à ondes élastiques et dispositif de communication
WO2020137263A1 (fr) Dispositif de filtrage
US20200145030A1 (en) Multiplexer
WO2023132354A1 (fr) Dispositif de filtre, diviseur et dispositif de communication
JPH11340779A (ja) 弾性表面波フィルタ、デュプレクサおよび通信機装置
WO2024106269A1 (fr) Filtre, module et dispositif de communication

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: 23827002

Country of ref document: EP

Kind code of ref document: A1