Saw resonator capable of adjusting singular points through phase change of surface acoustic wave, and manufacturing method therefor

Abstract

The objective of the present invention is to provide, in order to solve the described problems, a surface acoustic wave (SAW) resonator capable of adjusting singular points through a phase change of a surface acoustic wave, and a manufacturing method therefor, the SAW resonator changing the phase of a SAW generated and propagated in an IDT electrode unit of the SAW resonator, so as to intentionally adjust singular points, that is, a resonance frequency and an anti-resonance frequency according to desired design specifications, even if a capacitor is not additionally connected to the SAW resonator while an area of the SAW resonator is maintained as is, thereby enabling skirt characteristics of a SAW pass filter including the SAW resonator to be more sharply improved according to the design specifications.

Description

SAW resonator capable of controlling singularity through phase change of surface acoustic wave and method for manufacturing the same

[0001] The present invention relates to a SAW resonator capable of controlling a singularity through a change in the phase of a surface acoustic wave (SAW) generated from an IDT (Inter Digital Transducer) and propagated by a SAW resonator used in a filter that converts an electric signal into a surface acoustic wave of a piezoelectric material by utilizing the piezoelectric effect of the piezoelectric material and then converts the converted elastic wave back into an electric signal, thereby controlling the resonance and anti-resonance of the SAW resonator, thereby improving the skirt characteristics of a SAW filter equipped with the SAW resonator, and a method for manufacturing the same.

[0002] With the development of mobile communication devices such as smartphones and tablets, there is a growing demand for higher performance in surface acoustic wave elements and devices such as SAW resonators and filters utilizing them. In particular, with the advent of the 5G and 6G era, the number of surface acoustic wave filters used in mobile phones has increased significantly as the frequency that can be used in mobile environments has increased.

[0003] This requires miniaturization and integration of filters, as more filters and RF components must be added to the existing space.

[0004] The need to minimize the mutual interference between frequencies caused by these significantly increased elements is becoming increasingly important. To this end, the steep skirt characteristic of the response curve of a surface acoustic wave (SAW) filter is becoming increasingly important. This steep skirt characteristic is closely related to the resonant frequency (fr) and anti-resonant frequency (fa) of the SAW resonator.

[0005] FIG. 1 shows the structure of a conventional SAW resonator. Such a conventional SAW resonator has an interdigital transducer, i.e., an IDT structure (20), which is configured by arranging metal electrodes in parallel and continuously on a piezoelectric substrate (10) made of a piezoelectric material. When an AC signal voltage is applied to the IDT (20), an electric field is generated between the electrodes inside the IDT, and a deformation occurs on the surface of the substrate due to the piezoelectric effect of the piezoelectric substrate (10), and a surface acoustic wave (SAW) is propagated in both directions of the IDT.

[0006] In this way, the surface acoustic wave generated on the surface of the piezoelectric substrate (10) by the IDT (20) can perform the function of a bandpass filter that passes a frequency component that is synchronized with the frequency of the surface acoustic wave and attenuates the remaining signals in the process of being converted back into an electric signal by the output electrode within the IDT or another IDT placed adjacently.

[0007] At this time, a reflector (30, 40) that forms gratings of a metal film around the IDT (20) on the piezoelectric substrate (10) is provided so that the surface acoustic wave generated by the IDT (20) and propagated to the outside is reflected back to the IDT (20), thereby reducing loss.

[0008] The reflector of a typical SAW resonator reflects the surface acoustic wave generated from the IDT at both ends of the IDT in accordance with the Bragg condition, thereby confining the surface acoustic wave within the SAW resonator.

[0009] Meanwhile, Fig. 2 shows the response curve of a basic pass filter (FL) having a series SAW resonator (SAW(S)) connected in series with the SAW resonators as described above and a parallel SAW resonator (SAW(P)) connected in parallel.

[0010] In Fig. 2, the admittance curve (Y) versus frequency of the series SAW resonator (SAW(S)) of the filter (FL) is shown. 11(S) ) and the admittance curve (Y) versus frequency of the parallel SAW resonator (SAW(P)) 11(P) ), and insertion loss curves (S) versus frequency of filters (FL) having series SAW resonators (SAW(S)) and parallel SAW resonators (SAW(P)). 21 ) is shown.

[0011] Y 11(S) f on the curve r(s) Wow f a(s) are the resonant frequencies (f) of the series SAW resonators, respectively. r(s) ) and antiresonant frequency (f a(s) ) and Y 11(P) f on the curve r(p) Wow f a(p) are the resonant frequencies (f) of the parallel SAW resonators, respectively. r(p) ) and antiresonant frequency (f a(p) )am.

[0012] As shown in Fig. 2, the skirt characteristics in the stopband on the response curve of the filter are closely related to the resonant frequency and anti-resonant frequency of the SAW resonator constituting the filter.

[0013] The difference between the resonant and anti-resonant frequencies of a SAW resonator is the electromechanical coupling constant (K) of the piezoelectric material. 2 ) is determined by, and to control this, conventionally, a passive capacitor was connected externally in parallel to move the anti-resonant frequency toward the resonant frequency.

[0014] However, this method suffers from the problem of increasing the area of ​​the SAW resonator and filter due to the additional capacitors and the connecting lines for connecting them. This problem hinders the miniaturization and miniaturization of RF front-end modules for next-generation mobile communications, such as 5G and 6G.

[0015] The present invention is to solve the above problems, and to provide a SAW resonator capable of controlling singularities through phase change of surface acoustic waves, and a method for manufacturing the same, by intentionally controlling singularities, i.e., resonant frequency and anti-resonant frequency, to meet desired design specifications by changing the phase of surface acoustic waves (SAW) generated and propagated at an IDT electrode portion of a SAW resonator without additionally connecting a capacitor to the SAW resonator while maintaining the area of ​​the SAW resonator as is, thereby more steeply improving the skirt characteristics of a SAW pass filter including the SAW resonator according to design specifications.

[0016] According to one embodiment of the present invention, a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave comprises: a piezoelectric substrate; an IDT electrode part provided on the piezoelectric substrate and having a plurality of electrode fingers for converting an electric signal into a surface acoustic wave on the piezoelectric substrate; a reflector arranged in a propagation direction of the surface acoustic wave generated from the IDT electrode part and reflecting the surface acoustic wave toward the IDT electrode part, respectively; and a floating electrode provided within the IDT electrode part separately from the plurality of electrode fingers and capable of controlling a resonance and anti-resonance frequency, which are the singularity, by changing the phase of the surface acoustic wave generated from the IDT electrode part.

[0017] Meanwhile, a method for manufacturing a SAW resonator according to an embodiment of the present invention comprises a piezoelectric substrate, an IDT electrode part having a plurality of electrode fingers for generating surface acoustic waves on the piezoelectric substrate, and a reflector provided on both ends of the IDT electrode part, and a method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of the surface acoustic wave, the method comprising: a floating electrode determination step of determining a configuration of at least one of a type, a shape, a number, and a dimension of a floating electrode provided in the IDT electrode part separately from the plurality of electrode fingers and capable of controlling a resonance and anti-resonance frequency, which are the singularity, by changing the phase of the surface acoustic wave generated from the IDT electrode part, according to design specifications for obtaining a desired frequency response characteristic of the SAW resonator; and a step of forming the IDT electrode part, the reflector, and the floating electrode according to the determined configuration on the piezoelectric substrate.

[0018] The SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to the present invention and the manufacturing method thereof have the effect of allowing the skirt characteristics of a SAW pass filter including the SAW resonator to be improved more steeply in accordance with the design specifications by inserting a floating electrode into an IDT electrode section so as to change the phase of a surface acoustic wave (SAW) generated and propagated in the IDT electrode section of the SAW resonator and designing the floating electrode according to the desired design specifications to control the singularity, that is, the resonant frequency and the anti-resonant frequency.

[0019] Figure 1 is a diagram showing the configuration of a SAW resonator having a conventional IDT electrode and reflector.

[0020] Figure 2 is a diagram showing the response curve of a basic SAW pass filter having a series SAW resonator connected in series and a parallel SAW resonator connected in parallel.

[0021] FIG. 3 is a drawing showing the basic configuration of a SAW resonator according to one embodiment of the present invention.

[0022] Figure 4 is a flowchart showing a method for manufacturing a SAW resonator according to one embodiment of the present invention.

[0023] FIG. 5 (a) shows a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to one embodiment of the present invention, in which a floating finger is provided within an IDT electrode section, and FIG. 5 (b) is a drawing showing a cross-section II of (a).

[0024] Fig. 6 is a diagram comparing the admittance response curves of a conventional SAW resonator and a SAW resonator according to an embodiment of the present invention.

[0025] FIG. 7 is a drawing showing a case in which a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention is provided with a plurality of floating fingers arranged parallel to each other as floating electrodes within an IDT electrode section.

[0026] FIG. 8 is a diagram comparing the frequency response curve of the SAW resonator according to the embodiment illustrated in FIG. 7 with the response curve of a conventional SAW resonator.

[0027] FIG. 9 is a drawing showing a more generalized form having a plurality of floating fingers as floating electrodes within an IDT electrode portion, as in the embodiment illustrated in FIG. 7.

[0028] Figure 10 shows a comparison graph of response curves for various cases in which the number of floating fingers is odd compared to the number of electrode fingers of the IDT electrode portion in the configuration of the SAW resonator illustrated in Figure 9.

[0029] Figure 10 shows a graph comparing response curves in various cases where the floating fingers are provided in an even number in the case where the electrode fingers of the IDT electrode portion are an even number in the configuration of the SAW resonator illustrated in Figure 9.

[0030] FIG. 12 is a diagram showing a case where a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention has a floating column as a floating electrode within an IDT electrode section.

[0031] FIG. 13 is a drawing showing a case where a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention has a plurality of floating slit fingers as floating electrodes within an IDT electrode section.

[0032] FIG. 14 is a diagram showing a case where a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention has a plurality of floating multi-strips as floating electrodes within an IDT electrode section.

[0033] FIG. 15 is a diagram showing a case where a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention has a floating matrix as a floating electrode within an IDT electrode section.

[0034] FIG. 16 is a drawing showing a case where a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention has a zigzag slit electrode portion as a floating electrode within an IDT electrode portion.

[0035] FIG. 17 is a diagram showing a case where a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention has a floating grid electrode as a floating electrode within an IDT electrode section.

[0036] Figures 18 and 19 show frequency response curves versus insertion loss of an actual ladder-type SAW filter that uses a SAW resonator in which a floating electrode according to the present invention is inserted into an IDT electrode portion.

[0037] The specific details of a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to the present invention and a method for manufacturing the same are described in detail with reference to the drawings.

[0038] In order to meet the demand for miniaturization while supporting more frequency bands as mobile communication standard generations evolve, it is necessary to have a steep skirt characteristic on the response curve of the filter without increasing the area of ​​the SAW resonator. In order to meet these conditions, a SAW resonator according to an embodiment of the present invention inserts a floating electrode into an IDT electrode portion provided on a piezoelectric substrate, and designs and implements the floating electrode according to desired design specifications, thereby changing the phase of the surface acoustic wave generated from the IDT electrode portion, thereby adjusting the singularity, that is, the resonant frequency and the anti-resonant frequency, according to the desired design specifications, thereby further improving the skirt characteristic to be steeper.

[0039] Fig. 3 illustrates the basic configuration of a SAW resonator according to one embodiment of the present invention.

[0040] As illustrated in FIG. 3, a SAW resonator according to one embodiment of the present invention basically includes a piezoelectric substrate (100) made of a material having a piezoelectric effect, and an IDT electrode portion (200) provided on the piezoelectric substrate (100) to convert an electric signal into a surface acoustic wave on the piezoelectric substrate (100), or conversely, to convert a surface acoustic wave on the piezoelectric substrate (100) into an electric signal, or both.

[0041] The IDT electrode portion (200) on the above-described piezoelectric substrate (100) is configured with a plurality of electrode fingers (211, 251) that convert an electric signal into a surface acoustic wave on the piezoelectric substrate (100).

[0042] Specifically, as illustrated in FIG. 3, the IDT electrode unit (200) has a plurality of metal electrodes having a comb structure, that is, a plurality of electrode fingers are divided into an input IDT electrode unit (210) and an output IDT electrode unit (250), and a plurality of input electrode fingers (211) and a plurality of output electrode fingers (251) are alternately arranged, and an input electrode bus bar (220) connecting a plurality of input electrode fingers (211) and an output electrode bus bar (260) connecting a plurality of output electrode fingers (251) are provided, so that when an electric signal is applied through the input IDT electrode unit (210), a surface acoustic wave is generated on the piezoelectric substrate (100) by an electric field between the plurality of input electrode fingers (211) and the output electrode fingers (251), and the surface acoustic wave is converted into an electric signal and output to the output IDT electrode unit (220).

[0043] At this time, the surface acoustic wave generated from the IDT electrode portion (200) propagates in both directions, that is, in the left and right directions in the drawing.

[0044] By providing reflectors (510, 520) that form gratings of a metal film at both ends of the IDT electrode portion (200) in the direction of propagation of surface acoustic waves generated from the IDT electrode portion (200) on the piezoelectric substrate (100), the surface acoustic waves generated by the IDT electrode portion (200) and propagated to the outside are reflected back to the IDT electrode portion (200), thereby reducing the loss due to propagation of the surface acoustic waves. That is, the above-described reflectors (510, 520) reflect the surface acoustic waves generated from the IDT electrode portion (200) in accordance with the Bragg conditions at both ends of the IDT electrode portion (200), thereby confining the surface acoustic waves within the SAW resonator.

[0045] A SAW resonator according to one embodiment of the present invention is characterized in that it includes a floating electrode (300) that is provided separately from a plurality of electrode fingers within an IDT electrode portion (200) as shown in FIG. 3 and can control resonance and anti-resonance frequencies, which are singular points, by changing the phase of surface acoustic waves generated from the IDT electrode portion (200).

[0046] The floating electrode (300) is provided within the IDT electrode portion (200), and is spaced apart from the input electrode finger (211), the input electrode bus bar (220), the output electrode finger (251), and the output electrode bus bar (260) by a predetermined distance, and is placed between the input electrode finger (211) and the output electrode finger (251).

[0047] In this way, by inserting a floating electrode (300) between the electrode fingers of the IDT electrode portion (200), the in-phase and / or out-of-phase conditions of the surface acoustic wave generated and propagated from each electrode finger can be changed.

[0048] That is, the floating electrode shifts the phase of the surface acoustic wave, and such phase shift can electrically shift the singularities of the SAW resonator, i.e., the resonant frequency and the anti-resonant frequency, thereby forming new singularities.

[0049] The floating electrode as described above can have various types and shapes, and can finely control the phase shift or singular point shift of the surface acoustic wave depending on the type and shape of the floating electrode, the number and dimensions of the electrodes, etc. In addition, it can also perform the function of canceling out spurious responses such as unnecessary harmonics generated at a specific frequency, and can also be used to block leakage of SH SAW (Shear Horizontal SAW) generated in the IDT electrode section to the IDT bus bar.

[0050] The present invention is characterized in that it can provide a SAW resonator and a manufacturing method thereof, wherein the configuration of at least one of the type, shape, number, and dimensions of a floating electrode capable of controlling a singularity by changing the phase of a surface acoustic wave generated in an IDT electrode section as described above is determined according to design specifications for obtaining a desired frequency response characteristic, and manufactured accordingly.

[0051] FIG. 4 is a flowchart illustrating a method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to one embodiment of the present invention.

[0052] A method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to one embodiment of the present invention includes a step of designing a floating electrode according to predetermined design specifications for a SAW resonator, and a step of creating a SAW resonator having a floating electrode accordingly.

[0053] That is, as illustrated in FIG. 4, a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to an embodiment of the present invention can be manufactured by a step (S110) of determining a configuration of at least one of the type, shape, number, and dimensions of a floating electrode, which is provided separately from a plurality of electrode fingers within an IDT electrode portion and can control the resonance and anti-resonance frequencies, which are singular points, by changing the phase of a surface acoustic wave generated from the IDT electrode portion, according to design specifications for obtaining a desired frequency response characteristic, and a step (S120) of generating an IDT electrode portion, a reflector, and a floating electrode according to the configuration determined in the floating electrode determination step on a piezoelectric substrate.

[0054] Various embodiments according to the type, shape, number, dimensions, etc. of the floating electrode of the SAW resonator according to the present invention will be described in more detail below with reference to FIGS. 5 to 17. In the drawings below, descriptions of overlapping parts of common components such as the piezoelectric substrate (100), IDT electrode portion (200), and reflectors (510, 520) of the SAW resonator illustrated in FIG. 3 will be omitted, and the configuration of the floating electrode of each embodiment will be described primarily.

[0055] First, a SAW resonator and a manufacturing method thereof according to one embodiment of the present invention will be described with reference to FIGS. 5 and 6.

[0056] FIG. 5 (a) shows a case where a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to one embodiment of the present invention is provided with a floating finger (310) composed of a single metal finger body as a floating electrode within an IDT electrode portion (200), and FIG. 5 (b) shows a II cross-section of (a).

[0057] As shown in (a) and (b) of FIG. 5, a SAW resonator according to one embodiment of the present invention has a floating finger (310) composed of one metal finger body as a floating electrode.

[0058] The floating finger (310) can be configured to be spaced apart from the input electrode finger (211), the input electrode bus bar (220), the output electrode finger (251), and the output electrode bus bar (260) by a predetermined distance within the IDT electrode portion (200) and arranged between the input electrode finger (211) and the output electrode finger (251).

[0059] In this way, the admittance response curve for frequency in the case where one floating finger (310) is provided is shown in Fig. 6, comparing it with the case of a conventional SAW resonator without a floating finger.

[0060] In FIG. 6, the frequency response curve for a conventional SAW resonator (including an IDT electrode portion and a reflector) without a floating electrode is the curve indicated by Co in the black curve, and the frequency response curve for a SAW resonator according to an embodiment of the present invention having one floating finger (in the case of 50 electrode fingers of the IDT electrode portion) as a floating electrode is the curve indicated by Cf1 in the red curve.

[0061] As seen in the frequency response curve of Fig. 6, when one floating finger is provided between the IDT electrodes of the SAW resonator, the in-phase condition is changed by the floating finger, so that the resonant frequency (f) of a typical SAW resonator d1 ) has two frequencies (f f1 ) is divided into, and the anti-resonance frequency (f) is increased as the surface acoustic wave propagating additionally is stretched by the floating finger. d2 ) can be seen to move to a lower frequency than a typical SAW resonator, that is, toward the resonant frequency (f in Fig. 6). f2 The part referred to is the anti-resonant frequency moved by the floating finger).

[0062] Therefore, it can be seen that by inserting one floating finger into the IDT electrode portion as shown in (a) of Fig. 5, the frequency phase is changed, and the anti-resonant frequency is moved to a lower side as shown in Fig. 6, and accordingly, the skirt characteristics of the filter equipped with the SAW resonator can be further improved.

[0063] Here, as shown in (b) of Fig. 5, the thickness (t) of the floating finger (310) provided in the IDT electrode portion (200) f ) can be adjusted to change the mass loading effect within the IDT electrode portion (200), thereby finely controlling the movement of at least one of the resonant frequency and the anti-resonant frequency as described above.

[0064] A method for manufacturing a SAW resonator according to an embodiment of the present invention may include a step of determining a floating finger as a floating electrode provided in an IDT electrode section in step S110 of FIG. 4 described above, i.e., a floating electrode determination step, and a step of determining a metal thickness of the floating finger so as to achieve a desired singularity control through a phase change of a surface acoustic wave by the floating finger.

[0065] A SAW resonator according to one embodiment of the present invention is characterized in that it has a desired skirt improvement performance by having a metal thickness of a floating finger adjusted according to design specifications for obtaining a desired frequency response characteristic of the SAW resonator or a SAW filter including the SAW resonator as described above.

[0066] Meanwhile, a SAW resonator and a manufacturing method thereof according to another embodiment of the present invention will be described with reference to FIGS. 7 and 8.

[0067] FIG. 7 illustrates a case in which a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention is provided with a plurality of floating fingers (320) arranged in parallel to each other as floating electrodes within an IDT electrode portion (200).

[0068] In the embodiment illustrated in FIG. 7, the SAW resonator is provided with a plurality of floating fingers (321 and 322) each consisting of a single metal finger body as a floating electrode, arranged in parallel to each other.

[0069] A plurality of floating fingers (320) can be configured to be spaced apart from the input electrode finger (211), the input electrode bus bar (220), the output electrode finger (251), and the output electrode bus bar (260) by a predetermined distance within the IDT electrode portion (200) and arranged between the input electrode finger (211) and the output electrode finger (251).

[0070] At this time, as illustrated in FIG. 7, when the period length (Le) of the plurality of electrode fingers (211 or 251) of the IDT electrode portion (200) and the period length (Lf) of the plurality of floating fingers (321, 322) are made different, the resonant frequency and the anti-resonant frequency can be shifted by the difference between the period length Le of the IDT electrode portion and the period length Lf of the floating fingers.

[0071] In Fig. 8, the frequency response curve (Co) of a conventional SAW resonator without a floating electrode, the frequency response curve (Cf2) of a SAW resonator with a floating finger having a period length shorter than the period length of the IDT electrode portion, and the frequency response curve (Cf3) of a SAW resonator with a floating finger having a period length longer than the period length of the IDT electrode portion are compared in one graph.

[0072] As shown in FIGS. 7 and 8, the resonant frequency on the SAW resonator frequency response curve (Co) without a floating electrode is fr1 and the anti-resonant frequency is fa1. However, when the period length Lf of the plurality of floating fingers (321, 322) provided in the IDT electrode portion is made shorter than the period length Le of the IDT electrode portion, it can be seen that the resonant frequency shifts from fr1 to fr2 and the anti-resonant frequency shifts from fa1 to fa2.

[0073] In addition, it can be seen that when the period length Lf of the plurality of floating fingers (321, 322) provided in the IDT electrode part is made longer than the period length Le of the IDT electrode part, the resonant frequency moves from fr1 to fr3 and the anti-resonant frequency moves from fa1 to fa3.

[0074] Therefore, as illustrated in Fig. 8, by adjusting the difference between the period length Le of the IDT electrode portion and the period length Lf of the floating finger, the resonant frequency and the anti-resonant frequency can be precisely moved to meet the desired design specifications, and accordingly, it can be seen that the skirt characteristics of the filter equipped with the SAW resonator can be improved to meet the desired design specifications.

[0075] The method for manufacturing a SAW resonator according to the present embodiment may include a step of determining a plurality of floating fingers arranged in parallel to each other as floating electrodes provided in the IDT electrode section in step S110 of FIG. 4 described above, i.e., a step of determining a floating electrode, and a step of determining a periodic length of the plurality of floating fingers so as to achieve a desired singularity control through a phase change of a surface acoustic wave by the plurality of floating fingers.

[0076] That is, by setting the difference between the period lengths of multiple floating fingers and the period lengths of multiple electrode fingers of the IDT electrode portion as the difference value for obtaining a singularity according to the desired design specifications and determining the period lengths of multiple floating fingers according to the set difference value, it is possible to improve the skirt characteristics according to the design specifications for obtaining the desired frequency response characteristics.

[0077] Meanwhile, a SAW resonator and a manufacturing method thereof according to another embodiment of the present invention will be described with reference to FIGS. 9 to 11.

[0078] FIG. 9 shows a more generalized form of the embodiment illustrated in FIG. 7, which has a plurality of floating fingers as floating electrodes within the IDT electrode portion.

[0079] In the embodiments according to FIGS. 9 to 11, the present invention shows a case in which singularity control is achieved according to desired design specifications by adjusting the number of floating fingers.

[0080] In FIG. 9, the number of floating fingers (Nf(#1)) included in the first floating finger group (320) from the left in the IDT electrode portion (200) and the number of floating fingers (Nf(#i)) included in the ith floating finger group (320) are shown, and the number of electrode fingers (211, 251) included in the first IDT electrode finger group from the left based on each floating finger group (Ni(#1)), the number of electrode fingers (211, 251) included in the ith IDT electrode finger group (Ni(#i)), and the number of electrode fingers (211, 251) included in the nth IDT electrode finger group (Ni(#n)) are shown, respectively.

[0081] When the number of electrode fingers Ni(#i) of the ith IDT electrode part is configured so that the number of floating fingers Nf(#i) satisfies the condition mod(Ni(#i),2) ≠ mod(Nf(#i),2), the in-phase condition and out-of-phase condition of the surface acoustic wave generated from the IDT electrode part can be changed by the floating finger, so that the singularity can be adjusted according to the desired design specifications.

[0082] Here, the mod function is a function that calculates the remainder of division, mod(Ni, 2) means the remainder when Ni is divided by 2, and mod(Nf, 2) means the remainder when Nf is divided by 2.

[0083] For example, when the number of electrode fingers Ni of the IDT electrode part is an even number and the number of floating fingers Nf is an odd number, the above condition is satisfied and singularity control can be achieved by the phase change of the surface acoustic wave accordingly. Conversely, the same applies when the number of electrode fingers Ni of the IDT electrode part is an odd number and the number of floating fingers Nf is an even number.

[0084] FIG. 10 is an example of a configuration in which the number of the ith floating fingers Nf(#i) satisfies the condition mod(Ni(#i),2) ≠ mod(Nf(#i),2) for the number of electrode fingers Ni(#i) of the ith IDT electrode part, and shows frequency response curves for each case when the number of electrode fingers Ni of the IDT electrode part is an even number (Co), when there is one floating finger (Cn1), when there are three floating fingers (Cn3), when there are five floating fingers (Cn5), and when there are seven floating fingers (Cn7).

[0085] As shown in Fig. 10, when the condition mod(Ni(#i),2) ≠ mod(Nf(#i),2) is satisfied, the in-phase condition and out-of-phase condition of the surface acoustic wave generated from the IDT electrode section are changed by the floating finger, and the resonant frequency (fr1) and the anti-resonant frequency (fa1) on the response curve of the SAW resonator without the floating electrode shift as shown in the part indicated by frc when the floating finger is provided, and at the same time, the anti-resonant frequency also shifts as shown in the part indicated by fac.

[0086] Therefore, as illustrated in FIG. 10, by adjusting the number of floating fingers such that the number of floating fingers Nf satisfies the condition mod(Ni,2) ≠ mod(Nf,2) for the number of electrode fingers Ni of the IDT electrode portion, the resonant frequency and anti-resonant frequency can be moved precisely to meet the desired design specifications, and accordingly, the skirt characteristics of the filter equipped with the SAW resonator can be improved to meet the desired design specifications.

[0087] The method for manufacturing a SAW resonator according to the present embodiment may include a step of determining a floating electrode, such as one floating finger or a plurality of floating fingers arranged in parallel with each other, as a floating electrode provided in the IDT electrode part in step S110 of FIG. 4 described above, that is, a floating electrode determination step, and a step of determining the number of floating fingers such that the number of floating fingers Nf satisfies the condition mod(Ni,2) ≠ mod(Nf,2) for the number of electrode fingers Ni of the IDT electrode part so as to change the in-phase condition and the out-of-phase condition of the surface acoustic wave generated in the IDT electrode part according to the desired design specifications.

[0088] Accordingly, a SAW resonator with a floating electrode determined to satisfy the above conditions can achieve skirt characteristic improvement according to design specifications to obtain desired frequency response characteristics.

[0089] Meanwhile, in FIG. 9, when the number of the ith floating fingers Nf(#i) is configured to satisfy the condition of mod(Ni(#i),2) = mod(Nf(#i),2) for the number of electrode fingers Ni(#i) of the ith IDT electrode part, as shown in FIG. 11, since the in-phase condition of the surface acoustic wave generated and propagated from the IDT electrode part is the same, even if the floating fingers are provided to meet the above condition, the resonant frequency (fr1) remains almost the same (see the part indicated by frt in FIG. 11), but it can be seen that the anti-resonant frequency shifts toward a lower frequency than the anti-resonant frequency (fa1) of the typical SAW resonator as the surface acoustic wave transmitted by the floating fingers between the electrode fingers of the IDT electrode part is stretched more than that of a typical SAW resonator (see the part indicated by fat in FIG. 11).

[0090] For example, when the number of electrode fingers Ni of the IDT electrode part is an even number and the number of floating fingers Nf is an even number, the above condition is satisfied and singularity control can be achieved by the phase change of the surface acoustic wave accordingly. Conversely, the same applies when the number of electrode fingers Ni of the IDT electrode part is an odd number and the number of floating fingers Nf is an odd number.

[0091] FIG. 11 is an example of a configuration in which the number of the ith floating fingers Nf(#i) satisfies the condition mod(Ni(#i),2) = mod(Nf(#i),2) for the number of electrode fingers Ni(#i) of the ith IDT electrode part, and shows frequency response curves for each case when the number of electrode fingers Ni of the IDT electrode part is an even number (Co), when there are 2 floating fingers (Cn2), when there are 4 floating fingers (Cn4), when there are 6 floating fingers (Cn6), and when there are 8 floating fingers (Cn8).

[0092] As shown in Fig. 11, when the condition mod(Ni(#i),2) = mod(Nf(#i),2) is satisfied, the in-phase condition of the surface acoustic wave generated and propagated from the IDT electrode portion is the same, so the resonant frequencies (fr1 and frt)) remain almost the same, but since the surface acoustic wave transmitted by the floating finger between the electrode fingers of the IDT electrode portion is stretched more than that of a typical SAW resonator, the anti-resonant frequency (fat) shifts toward a lower frequency than the anti-resonant frequency (fa1) of a typical SAW resonator.

[0093] Therefore, as illustrated in FIG. 11, by adjusting the number of floating fingers so that the number of floating fingers Nf satisfies the condition mod(Ni,2) = mod(Nf,2) for the number of electrode fingers Ni of the IDT electrode portion, the anti-resonance frequency can be moved precisely to meet the desired design specifications, and accordingly, the skirt characteristics of the filter equipped with the SAW resonator can be improved to meet the desired design specifications.

[0094] The method for manufacturing a SAW resonator according to the present embodiment may include a step of determining a floating electrode, such as one floating finger or a plurality of floating fingers arranged in parallel with each other, as a floating electrode provided in the IDT electrode portion in step S110 of FIG. 4 described above, that is, a floating electrode determination step, and a step of determining the number of floating fingers such that the number of floating fingers Nf satisfies the condition mod(Ni,2) = mod(Nf,2) for the number of electrode fingers Ni of the IDT electrode portion according to a desired design specification.

[0095] Accordingly, a SAW resonator with a floating electrode determined to satisfy the above conditions can achieve skirt characteristic improvement according to design specifications to obtain desired frequency response characteristics.

[0096] Meanwhile, in FIG. 9, a SAW resonator according to another embodiment of the present invention can control the degree of shift of the resonant frequency and the anti-resonant frequency according to the ratio η (= Nf(#i) / Ni(#i)) of the number Nf(#i) of the ith floating finger to the number Ni(#i) of the electrode fingers of the ith IDT electrode portion.

[0097] However, if the ratio η of the number of floating fingers to the number of electrode fingers of the IDT electrode portion is outside a predetermined range, spurious responses may increase at frequencies other than singular points (resonant frequency and anti-resonant frequency), such as the Rs portion on the frequency response curve of FIG. 10 or the Rs1 and Rs2 portions on the frequency response curve of FIG. 11.

[0098] Therefore, by setting the ratio (η) of the number of floating fingers to the number of electrode fingers of the IDT electrode section to satisfy the range of 0.1 < η < 0.3, the skirt characteristics of a filter including a SAW resonator can be improved and the spurious response of the frequency can be minimized.

[0099] Meanwhile, a SAW resonator and a manufacturing method thereof according to another embodiment of the present invention will be described with reference to FIG. 12.

[0100] FIG. 12 illustrates a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention, in which a floating column (330) is provided as a floating electrode within an IDT electrode section (200).

[0101] The above-described floating column (330), as illustrated in FIG. 12, includes a plurality of floating fingers (331, 332) arranged parallel to each other, and a floating bus bar (333, 334) provided at each end thereof and formed so that both ends protrude further in the vertical direction from the plurality of floating fingers (331, 332) by connecting the plurality of floating fingers (331, 332), so that it can be formed in a shape similar to a shape in which a floor and a ceiling support a plurality of columns.

[0102] A floating column (330) having a plurality of floating fingers (331, 332) and a plurality of floating bus bars (333, 334) as described above can be configured to be spaced apart from the input electrode finger (211), the input electrode bus bar (220), the output electrode finger (251), and the output electrode bus bar (260) by a predetermined distance and arranged between the input electrode finger (211) and the output electrode finger (251) within the IDT electrode portion (200).

[0103] At this time, as illustrated in FIG. 12, when the period length (Le) of the plurality of electrode fingers (211 or 251) of the IDT electrode portion (200) and the period length (Lfb) of the plurality of floating fingers (331, 332) are made different, the resonant frequency and the anti-resonant frequency can be shifted by the difference between the period length Le of the IDT electrode portion and the period length Lfb of the floating fingers, as explained above through FIG. 8.

[0104] As described above, the present embodiment has a plurality of floating fingers (331, 332) and floating bus bars (333, 334) at each end thereof, and this configuration has the effect of suppressing spurious and harmonic components caused by SH SAW (Shear Horizontal SAW) of the SAW resonator.

[0105] The method for manufacturing a SAW resonator according to the present embodiment may include a step of determining a floating column having a plurality of floating fingers and a plurality of floating bus bars as a floating electrode provided in an IDT electrode section in step S110 of FIG. 4 described above, i.e., a floating electrode determination step, and a step of determining a configuration of the floating column so as to achieve desired singularity control and removal of unnecessary components such as spurious signals through a phase change of a surface acoustic wave by the floating column.

[0106] By determining the configuration of the floating column in this way, it is possible to improve the skirt characteristics according to the design specifications to obtain the desired frequency response characteristics.

[0107] Meanwhile, a SAW resonator and a manufacturing method thereof according to another embodiment of the present invention will be described with reference to FIG. 13.

[0108] FIG. 13 illustrates a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention, in which at least one floating slit finger (340) is provided as a floating electrode within an IDT electrode portion (200).

[0109] The floating slit finger (340) described above is configured by forming a plurality of slits (342) that penetrate the metal finger body in a direction perpendicular to its length direction, as illustrated in FIG. 13, and the slit width (Sw) of each of the plurality of slits (342) is formed to be smaller than the wavelength of the surface acoustic wave generated and propagated from the IDT electrode portion (200), thereby suppressing the leakage of the surface acoustic wave through each slit (342).

[0110] At least one floating slit finger (340) as described above may be configured to be spaced apart from the input electrode finger (211), the input electrode bus bar (220), the output electrode finger (251), and the output electrode bus bar (260) by a predetermined distance within the IDT electrode portion (200) and arranged between the input electrode finger (211) and the output electrode finger (251).

[0111] At this time, when the periodic lengths of the plurality of electrode fingers (211 or 251) of the IDT electrode portion (200) and the periodic lengths of the plurality of floating slit fingers (340) are made different, the resonant frequency and the anti-resonant frequency can be shifted by the difference between the periodic lengths of the IDT electrode portion and the periodic lengths of the floating slit fingers, as explained above through FIG. 8.

[0112] As described above, this embodiment has the effect of suppressing spurious and harmonic components caused by SH SAW (Shear Horizontal SAW) of a SAW resonator by forming a plurality of slits (342).

[0113] Furthermore, by adjusting the spacing between each slit in the floating slit finger (340) in which a plurality of slits (342) are formed, the propagation characteristics of the surface acoustic wave generated and propagated in the IDT electrode section can be adjusted. Therefore, by adjusting the spacing between the slits to suit the desired design specifications and configuring the floating slit finger, it is possible to obtain a singularity and improve the skirt characteristics according to the desired design specifications.

[0114] The method for manufacturing a SAW resonator according to the present embodiment may include a step of determining at least one floating slit finger as a floating electrode provided in the IDT electrode section in step S110 of FIG. 4 described above, i.e., a step of determining a configuration of the floating slit finger (spacing between multiple slits, periodic lengths of multiple fingers, number of floating slit fingers, etc.) so as to achieve desired singularity control and removal of unnecessary components such as spurious through phase change of surface acoustic waves by the floating slit finger.

[0115] By determining the configuration of the floating slit finger in this way, it is possible to improve the skirt characteristics according to the design specifications for obtaining the desired frequency response characteristics.

[0116] Meanwhile, a SAW resonator and a manufacturing method thereof according to another embodiment of the present invention will be described with reference to FIG. 14.

[0117] FIG. 14 illustrates a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention, in which a single floating multi-strip or a plurality of floating multi-strips (350) arranged in parallel to each other are provided as floating electrodes within an IDT electrode portion (200).

[0118] The floating multi-strip (350) described above, as illustrated in FIG. 14, is configured such that a plurality of metal strips (st1, st2) are arranged in a row with a predetermined gap (iw) between them, and a first strip (st1) and a second strip (st2) shorter than the first strip (st1) are arranged in a row alternately with the gap (iw) between them, and the width (iw) of the gap is formed to be smaller than the wavelength of the surface acoustic wave generated and propagated in the IDT electrode portion (200), thereby suppressing leakage of the surface acoustic wave through the gap (iw) between each metal strip (st1, st2).

[0119] At least one floating multi-strip (350) as described above can be configured to be spaced apart from the input electrode finger (211), the input electrode bus bar (220), the output electrode finger (251), and the output electrode bus bar (260) by a predetermined distance within the IDT electrode portion (200) and arranged between the input electrode finger (211) and the output electrode finger (251).

[0120] At this time, when the periodic lengths of the plurality of electrode fingers (211 or 251) of the IDT electrode portion (200) and the periodic lengths of the plurality of floating multi-strips (350) are different, the resonant frequency and the anti-resonant frequency can be shifted by the difference between the periodic lengths of the IDT electrode portion and the periodic lengths of the floating slit fingers, as explained above through FIG. 8.

[0121] As described above, the present embodiment has the effect of suppressing spurious and harmonic components caused by SH SAW (Shear Horizontal SAW) of a SAW resonator and controlling the propagation of surface acoustic waves generated in the IDT electrode section into various patterns by forming a first strip (st1) and a second strip (st2) arranged in a row with a gap (iw).

[0122] Furthermore, by controlling the arrangement of additional strips having different lengths from the first strip (st1) and the second strip (st2), the propagation characteristics of surface acoustic waves generated and propagated in the IDT electrode section can be controlled, and thus, by controlling the spacing between slits to suit the desired design specifications and configuring a floating slit finger, singular points can be obtained and skirt characteristics improved according to the desired design specifications.

[0123] The method for manufacturing a SAW resonator according to the present embodiment may include a step of determining at least one floating multi-strip as a floating electrode provided in an IDT electrode section in step S110 of FIG. 4 described above, i.e., a step of determining a configuration of a floating multi-strip (a plurality of gap-to-gap intervals, a periodic length between a plurality of floating multi-strips, the number of floating multi-strips, etc.) so as to achieve desired singularity control and removal of unnecessary components such as spurious through a phase change of a surface acoustic wave by the floating multi-strip.

[0124] By determining the configuration of the floating multi-strip in this way, it is possible to improve the skirt characteristics according to the design specifications to obtain the desired frequency response characteristics.

[0125] Meanwhile, a SAW resonator and a manufacturing method thereof according to another embodiment of the present invention will be described with reference to FIG. 15.

[0126] FIG. 15 illustrates a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention, in which a floating matrix (360) is provided as a floating electrode within an IDT electrode section (200).

[0127] The floating matrix (360) described above can be configured by alternately arranging slit fingers (361, 363) having a plurality of slits (sl) formed in a direction perpendicular to the length direction of the metal finger body, as illustrated in FIG. 15, and metal fingers (362, 364), and the slit width of each slit (sl) formed in the slit fingers (361, 363) can be configured to be smaller than the wavelength of the surface acoustic wave generated and propagated in the IDT electrode portion (200), thereby suppressing the leakage of the surface acoustic wave through each slit (sl).

[0128] The floating matrix (360) having the configuration described above can be configured by being spaced apart from the input electrode finger (211), the input electrode bus bar (220), the output electrode finger (251), and the output electrode bus bar (260) by a predetermined distance within the IDT electrode portion (200) and arranged between the input electrode finger (211) and the output electrode finger (251).

[0129] At this time, when the periodic length of the plurality of electrode fingers (211 or 251) of the IDT electrode portion (200) and the periodic length of the plurality of slit fingers and metal fingers are different, the resonant frequency and the anti-resonant frequency can be shifted by the difference between the periodic length of the IDT electrode portion and the periodic length of the plurality of slit fingers and metal fingers, as explained above through FIG. 8.

[0130] As described above, the present embodiment has the effect of suppressing spurious and harmonic components caused by SH SAW (Shear Horizontal SAW) of a SAW resonator by alternately forming slit fingers (361, 363) and metal fingers (362, 364), and can control the propagation of surface acoustic waves in various patterns.

[0131] The method for manufacturing a SAW resonator according to the present embodiment may include a step of determining a floating matrix as a floating electrode provided in the IDT electrode section in step S110 of FIG. 4 described above, i.e., a step of determining a configuration of a floating matrix so as to achieve desired singularity control and removal of unnecessary components such as spurious signals through a phase change of a surface acoustic wave by the floating matrix.

[0132] By determining the configuration of the floating matrix in this way, it is possible to improve the skirt characteristics according to the design specifications for obtaining the desired frequency response characteristics.

[0133] Meanwhile, a SAW resonator and a manufacturing method thereof according to another embodiment of the present invention will be described with reference to FIG. 16.

[0134] FIG. 16 illustrates a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention, in which a zigzag slit electrode portion (370) is provided as a floating electrode within an IDT electrode portion (200).

[0135] The above-described zigzag slit electrode portion (370), as illustrated in FIG. 16, includes a first slit electrode (371) configured by forming a plurality of first slits (sl1) penetrating one metal finger body in a direction perpendicular to its length, and a second slit electrode (372) configured by forming a plurality of second slits (sl2) penetrating another metal finger body in a direction perpendicular to its length, and the first slit (sl1) on the first slit electrode (371) and the second slit (sl2) on the second slit electrode (372) may be formed at different horizontal line positions, respectively.

[0136] At this time, the width of the first slit (sl1) and the width of the second slit (sl2) of the first slit electrode (371) are formed to be smaller than the wavelength of the surface acoustic wave generated and propagated in the IDT electrode section, thereby suppressing the surface acoustic wave from leaking through each of the first slit (sl1) and the second slit (sl2).

[0137] The zigzag slit electrode portion (370) as described above can be configured to be spaced apart from the input electrode finger (211), the input electrode bus bar (220), the output electrode finger (251), and the output electrode bus bar (260) by a predetermined distance, respectively, and arranged between the input electrode finger (211) and the output electrode finger (251) within the IDT electrode portion (200).

[0138] At this time, when the periodic lengths of the plurality of electrode fingers (211 or 251) of the IDT electrode portion (200) and the periodic lengths of the plurality of slit electrodes (371, 372) are made different, the resonant frequency and the anti-resonant frequency can be shifted by the difference between the periodic length of the IDT electrode portion and the periodic length of the zigzag slit electrode portion, as explained above through FIG. 8.

[0139] As described above, this embodiment has the effect of minimizing the distortion of the propagation of surface acoustic waves generated in the IDT electrode section by arranging multiple slits (sl1, sl2) in a zigzag pattern to cancel out harmonic components that may be generated in each slit.

[0140] By adjusting the spacing between each slit (sl1 or sl2) in each of the first slit electrode (371) and the second slit electrode (372), the propagation characteristics of the surface acoustic wave generated and propagated in the IDT electrode section can be adjusted. Therefore, by adjusting the spacing between the slits to suit the desired design specifications and configuring the zigzag slit electrode section, it is possible to obtain a singularity and improve the skirt characteristics according to the desired design specifications.

[0141] The method for manufacturing a SAW resonator according to the present embodiment may include a step of determining a zigzag slit electrode portion as a floating electrode provided in the IDT electrode portion in step S110 of FIG. 4 described above, that is, a step of determining a floating electrode, as described above, in the IDT electrode portion; a step of determining a width of a first slit of a first slit electrode and a width of a second slit of a second slit electrode so as to be smaller than a wavelength of a surface acoustic wave generated and propagated in the IDT electrode portion; and a step of determining a plurality of first slit-intervals of a first slit electrode, a plurality of second slit-intervals of a second slit electrode, and a number of repeated arrangements of the first slit electrode and the second slit electrode so as to shift a resonant frequency and an anti-resonant frequency in a frequency response according to a desired design specification.

[0142] By determining the configuration of the zigzag slit electrode section in this way, it is possible to improve the skirt characteristics according to the design specifications for obtaining the desired frequency response characteristics.

[0143] Meanwhile, a SAW resonator and a manufacturing method thereof according to another embodiment of the present invention will be described with reference to FIG. 17.

[0144] Fig. 17 illustrates a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to another embodiment of the present invention, in which a floating grid electrode (380) is provided as a floating electrode within an IDT electrode portion (200).

[0145] The above-described floating grid electrode (380) can be configured to form a grid pattern by intersecting a plurality of row spacings (rw1, rw2, rw3, rw4, etc.) and a plurality of column spacings (cl1, cl2, cl3, cl4, etc.) on a metal plate, as illustrated in FIG. 17.

[0146] At this time, the width of each row spacing (rw1, rw2, rw3, rw4, etc.) and the width of each column spacing (cl1, cl2, cl3, cl4, etc.) are formed to be smaller than the wavelength of the surface acoustic wave generated and propagated from the IDT electrode section, thereby suppressing the leakage of the surface acoustic wave through each row spacing and each column spacing.

[0147] The floating grid electrode (380) as described above can be configured to be spaced apart from the input electrode finger (211), the input electrode bus bar (220), the output electrode finger (251), and the output electrode bus bar (260) by a predetermined distance within the IDT electrode portion (200) and arranged between the input electrode finger (211) and the output electrode finger (251).

[0148] As described above, this embodiment has a special feature of being able to control surface acoustic waves generated and propagated in the IDT electrode portion in various ways through a grid pattern with multiple row spacings and column spacings by providing a floating grid electrode (380) within the IDT electrode portion (200).

[0149] By appropriately changing the shape of the grid pattern of the floating grid electrode (380) as described above, the propagation characteristics of the surface acoustic wave generated and propagated in the IDT electrode section can be controlled, so that the floating grid electrode can be configured to meet the desired design specifications, thereby obtaining a singularity and improving the skirt characteristics according to the desired design specifications.

[0150] The method for manufacturing a SAW resonator according to the present embodiment may include a step of determining a floating grid electrode as a floating electrode provided in an IDT electrode section in step S110 of FIG. 4 described above, i.e., a step of determining a floating electrode, the width of each row spacing and column spacing being smaller than the wavelength of a surface acoustic wave generated and propagated in the IDT electrode section, and a step of determining the dimensions and shape of the grid pattern, such as the number of row spacings and the number of column spacings of the floating grid electrode, so as to shift the resonant frequency and the anti-resonant frequency in the frequency response according to the desired design specifications.

[0151] By determining the configuration of the floating grid electrode in this way, it is possible to improve the skirt characteristics according to the design specifications for obtaining the desired frequency response characteristics.

[0152] FIG. 18 and FIG. 19 are frequency response curves versus insertion loss of an actual ladder-type SAW filter that uses a SAW resonator with a floating electrode inserted into an IDT electrode portion according to the present invention, and are shown by comparing the frequency response curve (Ro) versus insertion loss of a filter that uses a conventional (non-floating electrode) SAW resonator and the frequency response curve (Rf) versus insertion loss of a filter that uses a SAW resonator with a floating electrode inserted into an IDT electrode portion according to the present invention.

[0153] As shown in FIGS. 18 and 19, it can be seen that the response (Rf) of the filter to which the SAW resonator equipped with a floating electrode according to the present invention is applied, compared to the response (Ro) of the filter to which the conventional SAW resonator is applied, has a significantly improved suppression effect in the counter band as the skirt (SK) drops more steeply in the guardband.

[0154] At this time, the improved skirt characteristic (SK) of the filter to which the SAW resonator equipped with a floating electrode according to the present invention is applied ensures a margin for maintaining the steep skirt characteristic even when a change occurs in which the frequency shifts to a higher side due to other factors.

[0155] That is, the improved skirt characteristics according to the present invention are the margin (Δf) due to the frequency shift of the filter due to temperature variation and the center frequency shift of the filter due to process variation. margin ) to ensure that it can be secured.

[0156] In addition, it goes without saying that the floating electrode proposed in the present invention can be applied not only to a one-port SAW resonator but also to a two-port SAW resonator such as a DMS (Double Mode SAW).

[0157] As described above, the SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to the present invention and the method for manufacturing the same have a special advantage in that the skirt characteristics of a SAW pass filter including the SAW resonator can be improved more steeply in accordance with the design specifications by inserting a floating electrode into the IDT electrode section so as to change the phase of a surface acoustic wave (SAW) generated and propagated in the IDT electrode section of the SAW resonator and designing the floating electrode in accordance with the desired design specifications to control the singularity, that is, the resonant frequency and the anti-resonant frequency.

[0158] The SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave according to the present invention and the method for manufacturing the same have industrial applicability in the technical field related to components of communication-based equipment such as GPS, Bluetooth, and digital TV, as well as digital wireless communication terminals such as smartphones, tablets, and personal portable terminals.

Claims

1. A SAW resonator capable of controlling singularity through phase change of surface acoustic waves. piezoelectric substrate; An IDT electrode section having a plurality of electrode fingers mounted on the piezoelectric substrate and converting an electric signal into a surface acoustic wave on the piezoelectric substrate; A reflector positioned in the propagation direction of the surface acoustic wave generated from the IDT electrode portion to reflect the surface acoustic wave to the IDT electrode portion; and A floating electrode provided separately from the plurality of electrode fingers within the IDT electrode portion and capable of controlling the resonance and anti-resonance frequencies, which are the singular points, by changing the phase of the surface acoustic wave generated from the IDT electrode portion; A SAW resonator capable of controlling singularity through phase change of surface acoustic waves including .

2. In the first paragraph, the IDT electrode part, An input IDT electrode section having a plurality of input electrode fingers for applying the above electric signal and an input electrode bus bar connecting the plurality of input electrode fingers; A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it includes an output IDT electrode section having a plurality of output electrode fingers that are arranged alternately with each of the plurality of input electrode fingers and generate the surface acoustic wave on the piezoelectric substrate when the electric signal is applied, and an output electrode bus bar that connects the plurality of output electrode fingers.

3. In the second paragraph, the floating electrode, The input electrode finger, the input electrode bus bar, the output electrode finger and the output electrode bus bar are spaced apart from each other by a predetermined distance and include one floating finger or a plurality of floating fingers arranged parallel to each other between the input electrode finger and the output electrode finger, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that the metal thickness of the floating finger is adjusted according to the design specifications for obtaining a desired frequency response characteristic of the SAW resonator or a SAW filter including the SAW resonator.

4. In the second paragraph, the floating electrode, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it includes a plurality of floating fingers arranged between the input electrode fingers and the output electrode fingers and arranged parallel to each other, each of which is spaced apart from the input electrode fingers, the input electrode busbar, the output electrode fingers, and the output electrode busbar by a predetermined distance, and a floating busbar provided at each end of the plurality of floating fingers and formed such that both ends further protrude in a direction perpendicular to the plurality of floating fingers by connecting the plurality of floating fingers.

5. In the third or fourth paragraph, the floating electrode, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that the number of floating fingers Nf is configured to satisfy the condition of mod(Ni,2) ≠ mod(Nf,2) for the number of electrode fingers Ni of the IDT electrode portion, thereby changing the in-phase condition and out-of-phase condition of the surface acoustic wave generated from the IDT electrode portion to obtain the singularity according to the desired design specifications.

6. In the third or fourth paragraph, the floating electrode, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that the number of floating fingers Nf is configured to satisfy the condition of mod(Ni,2) = mod(Nf,2) for the number of electrode fingers Ni of the IDT electrode portion, thereby shifting the anti-resonant frequency on the frequency response of the SAW resonator or a SAW filter including the SAW resonator to obtain the singularity according to a desired design specification.

7. In the third or fourth paragraph, the floating electrode, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that the plurality of floating fingers are arranged so as to have a set difference value that is set to a value that enables obtaining the singularity according to a desired design specification, wherein the difference value between the period length of the plurality of floating fingers and the period length of the plurality of electrode fingers of the IDT electrode part is a value.

8. In the third or fourth paragraph, the floating electrode, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that the number of floating fingers is provided such that the ratio of the number of floating fingers Nf to the number of electrode fingers Ni of the IDT electrode portion is greater than 0.1 and less than 0.

3.

9. In the second paragraph, the floating electrode, The input electrode finger, the input electrode bus bar, the output electrode finger, and the output electrode bus bar each include at least one floating slit finger spaced apart from the input electrode finger and the output electrode finger by a predetermined distance, The above floating slit finger, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that a plurality of slits are formed in a direction perpendicular to the length direction of a metal finger body, and the slit width of each of the plurality of slits is formed to be smaller than the wavelength of a surface acoustic wave generated and propagated from the IDT electrode portion.

10. In paragraph 9, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that a plurality of floating slit fingers are arranged so as to have a set difference value that is set to a value that enables obtaining the singularity according to a desired design specification, wherein the difference value between the periodic length of the plurality of floating slit fingers and the periodic length of the plurality of electrode fingers of the IDT electrode portion is a value.

11. In the 9th paragraph, the floating electrode, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that a metal finger in which a slit is not formed is arranged between one floating slit finger and another floating slit finger of the plurality of floating slit fingers.

12. In the second paragraph, the floating electrode, The input electrode finger, the input electrode bus bar, the output electrode finger, and the output electrode bus bar each include at least one floating multi-strip spaced apart from each other by a predetermined distance and arranged between the input electrode finger and the output electrode finger, The above floating multi-strip is, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that a plurality of metal strips are arranged in a row with a predetermined gap between them, and a first strip and a second strip shorter than the first strip are arranged in a row alternately with the gap between them, and the width of the gap is formed to be smaller than the wavelength of a surface acoustic wave generated and propagated from the IDT electrode portion.

13. In the second paragraph, the floating electrode, It includes a zigzag slit electrode portion spaced apart from the input electrode finger, the input electrode bus bar, the output electrode finger, and the output electrode bus bar by a predetermined distance and placed between the input electrode finger and the output electrode finger, The above zigzag slit electrode part, A first slit electrode is formed by forming a plurality of first slits penetrating in a direction perpendicular to the length direction of a metal finger body, and a second slit electrode is formed by forming a plurality of second slits penetrating in a direction perpendicular to the length direction of another metal finger body, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that the first slit on the first slit electrode and the second slit on the second slit electrode are each formed at different horizontal line positions, and the width of the first slit and the width of the second slit are each formed to be smaller than the wavelength of a surface acoustic wave generated and propagated in the IDT electrode portion.

14. In the second paragraph, the floating electrode, The input electrode finger, the input electrode bus bar, the output electrode finger, and the output electrode bus bar are spaced apart from each other by a predetermined distance and include a floating grid electrode disposed between the input electrode finger and the output electrode finger, The above floating grid electrode is, A SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that a plurality of row spacings and a plurality of column spacings intersect on a metal plate to form a grid pattern, and the width of each row spacing and column spacing is formed to be smaller than the wavelength of a surface acoustic wave generated and propagated from the IDT electrode portion.

15. A method for manufacturing a SAW resonator having a piezoelectric substrate, an IDT electrode portion having a plurality of electrode fingers that generate surface acoustic waves on the piezoelectric substrate, and a reflector provided on both ends of the IDT electrode portion, and capable of controlling a singularity through a phase change of the surface acoustic wave, A floating electrode determination step for determining the configuration of at least one of the type, shape, number, and dimensions of a floating electrode that is provided separately from the plurality of electrode fingers within the IDT electrode section and can control the resonance and anti-resonance frequencies, which are the singular points, by changing the phase of the surface acoustic wave generated from the IDT electrode section, according to design specifications for obtaining the desired frequency response characteristics of the SAW resonator; and A step of creating the IDT electrode part, the reflector, and the floating electrode according to the determined configuration on the piezoelectric substrate; A method for manufacturing a SAW resonator capable of controlling singularity through phase change of surface acoustic waves including .

16. In the 15th paragraph, the floating electrode determination step is: A step of determining one floating finger or a plurality of floating fingers arranged parallel to each other as the floating electrode, A method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it includes a step of determining a metal thickness of the floating finger so that the desired singularity can be controlled through a phase change of the surface acoustic wave by the floating finger.

17. In the 15th paragraph, the floating electrode determination step is: A step of determining one floating finger or a plurality of floating fingers arranged parallel to each other as the floating electrode, A method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it includes a step of determining the number of floating fingers such that the number Nf of floating fingers satisfies the condition mod(Ni,2) ≠ mod(Nf,2) with respect to the number Ni of electrode fingers of the IDT electrode portion so as to change the in-phase condition and out-of-phase condition of the surface acoustic wave generated from the IDT electrode portion according to a desired design specification.

18. In the 15th paragraph, the floating electrode determination step is: A step of determining one floating finger or a plurality of floating fingers arranged parallel to each other as the floating electrode, A method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it comprises a step of determining the number of floating fingers such that the number of floating fingers Nf satisfies the condition of mod(Ni,2) = mod(Nf,2) with respect to the number of electrode fingers Ni of the IDT electrode part so as to shift the anti-resonance frequency on the frequency response according to the desired design specifications.

19. In the 15th paragraph, the floating electrode determination step is: A step of determining a plurality of floating fingers arranged parallel to each other as the floating electrode, A method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it comprises a step of setting a difference value between the periodic length of the plurality of floating fingers and the periodic length of the plurality of electrode fingers of the IDT electrode portion as a difference value that can obtain the singularity according to a desired design specification, and determining the number and periodic length of the floating fingers according to the set difference value.

20. In the 15th paragraph, the floating electrode determination step is: A step of determining one floating finger or a plurality of floating fingers arranged parallel to each other as the floating electrode, A method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it includes a step of determining the number of floating fingers so that the ratio of the number Nf of floating fingers to the number Ni of electrode fingers of the IDT electrode part is greater than 0.1 and less than 0.

3.

21. In the 15th paragraph, the floating electrode determination step is: A step of determining a single floating slit finger or a plurality of floating slit fingers arranged parallel to each other, wherein a plurality of slits are formed in a direction perpendicular to the length direction of the metal finger body as the floating electrode, A step of determining the slit width of each of the plurality of slits so as to be smaller than the wavelength of the surface acoustic wave generated and propagated from the IDT electrode section; A method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it comprises a step of determining the spacing between the plurality of slits of the floating slit fingers and the number of the floating slit fingers so as to move the resonant frequency and the anti-resonant frequency in the frequency response according to the desired design specifications.

22. In the 15th paragraph, the floating electrode determination step is: A step of determining a floating multi-strip or a plurality of floating multi-strips arranged in a row with a plurality of metal strips separated by a predetermined gap as the floating electrode, wherein a first strip and a second strip shorter than the first strip are alternately arranged in a row with the gap separated by the gap; A step of determining the width of the gap so as to be smaller than the wavelength of the surface acoustic wave generated and propagated from the IDT electrode section, A method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it comprises a step of determining the length of the first strip and the length of the second strip, and the number of each of the first strip and the second strip, so as to shift the resonant frequency and the anti-resonant frequency in the frequency response according to a desired design specification.

23. In the 15th paragraph, the floating electrode determination step is: A step of determining a zigzag slit electrode portion, wherein the floating electrode comprises a first slit electrode formed by forming a plurality of first slits penetrating a metal finger body in a direction perpendicular to the longitudinal direction thereof, and a second slit electrode formed by forming a plurality of second slits penetrating another metal finger body in a direction perpendicular to the longitudinal direction thereof, wherein the first slit on the first slit electrode and the second slit on the second slit electrode are formed at different horizontal line positions, A step of determining the width of the first slit and the width of the second slit so as to be smaller than the wavelength of the surface acoustic wave generated and propagated from the IDT electrode portion; A method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it comprises a step of determining a plurality of first slit-intervals of the first slit electrodes, a plurality of second slit-intervals of the second slit electrodes, and a number of repeated arrangements of the first slit electrodes and the second slit electrodes so as to shift the resonant frequency and the anti-resonant frequency in the frequency response according to a desired design specification.

24. In the 15th paragraph, the floating electrode determination step is: A step of determining a floating grid electrode configured to form a grid pattern by intersecting a plurality of row spacings and a plurality of column spacings on a metal plate as the floating electrode; A step of determining the width of each row spacing and column spacing so as to be smaller than the wavelength of the surface acoustic wave generated and propagated from the IDT electrode section, A method for manufacturing a SAW resonator capable of controlling a singularity through a phase change of a surface acoustic wave, characterized in that it includes a step of determining the number of row spacings and the number of column spacings of the floating grid electrodes so as to shift the resonant frequency and the anti-resonant frequency in the frequency response according to a desired design specification.

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