WO2003052930A1 - Circuit de filtrage - Google Patents
Circuit de filtrage Download PDFInfo
- Publication number
- WO2003052930A1 WO2003052930A1 PCT/JP2002/013088 JP0213088W WO03052930A1 WO 2003052930 A1 WO2003052930 A1 WO 2003052930A1 JP 0213088 W JP0213088 W JP 0213088W WO 03052930 A1 WO03052930 A1 WO 03052930A1
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- WIPO (PCT)
- Prior art keywords
- frequency
- surface acoustic
- filter circuit
- acoustic wave
- wave resonator
- Prior art date
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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
- H03H9/6423—Means for obtaining a particular transfer characteristic
- H03H9/6433—Coupled resonator filters
- H03H9/6483—Ladder SAW filters
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/0115—Frequency selective two-port networks comprising only inductors and capacitors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/17—Structural details of sub-circuits of frequency selective networks
- H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
- H03H7/1758—Series LC in shunt or branch path
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/17—Structural details of sub-circuits of frequency selective networks
- H03H7/1741—Comprising typical LC combinations, irrespective of presence and location of additional resistors
- H03H7/1766—Parallel LC in series path
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/46—Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
- H03H7/463—Duplexers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
- H03H7/0123—Frequency selective two-port networks comprising distributed impedance elements together with lumped impedance elements
Definitions
- the present invention relates to a filter circuit for transmitting signals within a specific frequency range and attenuating signals outside the specific frequency range used in communication equipment and the like.
- FIG. 1 is a configuration diagram showing a conventional filter circuit described in, for example, Japanese Patent Application Laid-Open No. 10-126262 (hereinafter referred to as Reference 1).
- Reference 1 indicates a parallel element.
- the surface acoustic wave resonator to be constituted 2 is a surface acoustic wave resonator constituting a series element, 3 is an input terminal, 4 is an input-side ground terminal, 5 is an output terminal, and 6 is an output-side ground terminal.
- FIG. 2 is a configuration diagram showing a specific example of a surface acoustic wave resonator.
- the upper electric terminal 7 has the same potential as the input terminal 3
- the lower electric terminal 8 has the same potential as the input-side ground terminal 4.
- FIG. 3 is a structural diagram showing a specific structure of the surface acoustic wave resonator 1.
- reference numeral 9 denotes an IDT (Inter Digital Transducer), and an electrode finger 10 having a thickness of dl is disposed at a distance P 1 and are arranged crossing each other over a width W.
- IDT Inter Digital Transducer
- Reference numeral 11 denotes a reflector, and a large number of metal strips 12 having a thickness d2 are arranged at an interval P2 similarly to the IDT 9.
- Fig. 3 shows the case of a short strip reflector connected so that all metal strips 12 have the same potential, but the metal strips 12 are independent.
- an open strip that does not electrically connect the metal strips 12 to each other so as to have a potential is used.
- the distance between IDT 9 and reflector 11 is gl and g2, respectively, and g1 and g2 often use the same value.
- the arrangement interval P1 of the electrode fingers 10 coincides with the half of the wavelength of the surface acoustic wave, the surface acoustic wave is efficiently excited. That is, the arrangement interval P1 of the electrode fingers 10 determines the operating frequency of the surface acoustic wave resonator.
- the surface acoustic wave excited between each electrode finger 10 propagates in two directions perpendicular to the electrode finger 10, and the two reflectors 11 Propagation in the direction.
- reflection of surface acoustic waves occurs at the end face of the metal strip 12 due to the difference between the mass load of the metal strip 12 and the electrical boundary conditions.
- the arrangement interval P2 of the metal strips 12 matches the half-wavelength of the surface acoustic wave / 2
- the reflected waves at the end faces of the metal strips 12 all have the same phase. Therefore, strong reflection occurs.
- the surface acoustic wave excited by the IDT 9 is reflected by the reflectors 11 on both sides, the energy of the surface acoustic wave is confined, and operates as a resonator.
- the surface acoustic wave resonator has a minimum input impedance at the resonance frequency f r, and an input admittance at the anti-resonance frequency f a . Minimum.
- the resonance frequency f P is lower than the anti-resonance frequency f a .
- FIG. 4 is a circuit diagram showing an equivalent circuit of the surface acoustic wave resonator.
- reference numeral 13 denotes an electrode capacitance C of the IDT 9 in FIG.
- 14 is an inductor 1 ⁇
- 15 is a capacitor.
- the anti-resonance frequency f a of the surface acoustic wave resonator is the frequency of the parallel resonance between the electrode capacitance 13 and the series circuit (the inductor 14 and the capacitor 15).
- the impedance between the electric terminals 7 and 8 is almost open.
- Reference 2 shows an equivalent circuit that takes into account the resistance component R1 in the inductor 14 and the Q factor (Quality Factor) in series resonance.
- the impedance between the electric terminal 7 and the electric terminal 8 of the surface acoustic wave resonator at the resonance frequency f P is not a complete short circuit but a minimum value.
- FIG. 5 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- Figure 5A shows the impedance characteristics of a series element surface acoustic wave resonator 2.
- 5B shows the admittance characteristics of the parallel element surface acoustic wave resonator 1.
- Fig. 5C shows the series element surface acoustic wave resonator 2 and the parallel element surface acoustic wave resonator 1.
- 5 shows the filter characteristics when the connection is made as shown in FIG.
- the surface acoustic wave resonator 2 as a series element exhibits series resonance at a frequency f P 2 and parallel resonance at a frequency f ra 2. That is, the surface acoustic wave resonator 2 has a resonance frequency of: f f 2 and an anti-resonance frequency of f a 2 .
- the vertical axis in FIG. 5A indicates the imaginary part of the impedance of the surface acoustic wave resonator 2.
- the surface acoustic wave resonator 2 has a capacitance C in a frequency range where surface acoustic waves are not excited. It operates as a capacitor having Therefore, the imaginary part shows a negative impedance on the lower frequency side than the resonance frequency: 2 and on the higher frequency side than the anti-resonance frequency: f a 2 .
- the parallel element surface acoustic wave resonator 1 has the frequency fr! Indicates series resonance, and the frequency f a ! Indicates parallel resonance. That is, the surface acoustic wave resonator 1 has a resonance frequency f r ! And the anti-resonance frequency is f a 1 .
- the vertical axis in FIG. 5B represents the imaginary part of the admittance of the surface acoustic wave resonator 1.
- the surface acoustic wave resonator 1 has a resonance frequency fp! Than the lower frequency side and the anti-resonant frequency: f a ! At higher frequencies, the imaginary part shows a positive admittance.
- the resonance frequency fp 2 of the surface acoustic wave resonator 2 and the anti-resonance frequency f a ! Of the surface acoustic wave resonator 1! are set to be substantially equal to each other.
- the surface acoustic wave resonator 2 the resonance frequency: The frequency in the vicinity of fp 2, since I Npi one dance becomes almost zero, a state of a short circuit.
- the surface acoustic wave resonator 1 has an anti-resonance frequency f r ! At frequencies near, the admittance is almost zero, so it is almost open. Therefore, the input terminal
- the resonance frequency fr r of the surface acoustic wave resonator 1! At frequencies near this, the surface acoustic wave resonator 1 is almost short-circuited. At this time, since the input terminal 3 and the ground terminal 4 on the input side are almost short-circuited, and the output terminal 5 and the ground terminal 6 on the output side are almost short-circuited, an electric signal is transmitted from the input terminal 3 to the output terminal 5. They cannot be transmitted and form large attenuation poles.
- the surface acoustic wave resonator 2 is almost open. Therefore, an electric signal cannot be transmitted from the input terminal 3 to the output terminal 5, and a large attenuation pole is formed. Since this attenuation pole has a frequency near the anti-resonance frequency f a 2 of the surface acoustic wave resonator 2, it is higher than the resonance frequency fr 2 of the surface acoustic wave resonator 2 which is a pass band of the filter circuit. Limited to frequency.
- the operation of the filter circuit shown in FIG. 1 shows the same characteristics in a resonator other than the surface acoustic wave resonator. For example, even when a bulk wave resonator using thickness longitudinal vibration or thickness shear vibration is used. The same is true.
- Equation (3) indicates that the difference between the resonance frequency f r of the bulk wave resonator and the anti-resonance frequency f a is half of the value obtained by multiplying the electromechanical coupling coefficient k 2 of the piezoelectric material used by the anti-resonance frequency: a It shows that they almost match. This relationship is almost the same for the surface acoustic wave resonator.
- a filter circuit is formed using a surface acoustic wave resonator such as a bulk wave resonator or a surface acoustic wave resonator, the frequency of the passband of the filter circuit and the frequency of the attenuation pole at which a large attenuation can be obtained are obtained.
- the piezoelectric element used in the surface acoustic wave resonator lithium niobate (L i N b 03) or lithium tantalate (L i T a 0 3) is widely known, these electromechanical coefficient k 2 is a dozen percent greater. Therefore, the difference between the frequency in the passband of the filter circuit and the frequency of the attenuation pole at which large attenuation can be obtained is a problem that can only be obtained up to about 5 to 6% of the frequency in the passband of the filter circuit. there were.
- FIG. 6 is a block diagram showing a conventional filter circuit disclosed in, for example, Japanese Patent Application Laid-Open No. 6-350390 (hereinafter referred to as Document 4).
- Document 4 Japanese Patent Application Laid-Open No. 6-350390
- the configuration is such that a, the second surface acoustic wave resonator 2b, and the inductor 16 are series elements, and the parallel resonance circuit of the inductor 14 and the capacitor 15 is parallel elements.
- FIG. 7 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- the first is the impedance characteristic 17 of the first surface acoustic wave resonator 2a
- the impedance characteristic 18 of the second surface acoustic wave resonator 2 b and the impedance characteristic 19 of the inductor 16 are shown.
- the first surface acoustic wave resonator 2a has a resonance frequency fr ! , Anti-resonant frequency f a
- the second surface acoustic wave resonator 2 b has a resonance frequency: fr 2 and an anti-resonance frequency f a 2 .
- Fig. 7B shows the admittance characteristics 20 of the parallel resonance circuit of the inductor 14 and the capacitor 15.
- Frequency f ap is antiresonance frequency of the parallel resonance circuit, the resonance frequency f r 2 antiresonance frequency f a i and a second surface acoustic wave resonator 2 b of the first SAW resonator 2 a
- the anti-resonance frequency f a p is set so as to be between.
- Fig. 7A shows the vertical axis when the filter circuit of Fig. 6 is configured.
- the anti-resonance frequency f ap of the parallel resonance circuit composed of the inductor 14 and the capacitor 15 is set to a frequency f pa 3 s near the pass band of the filter circuit, the impedance of the parallel resonance circuit is Is almost open.
- the first surface acoustic wave resonator 2a has an anti-resonance frequency: a ! Operating at higher frequencies, it has a capacitive impedance.
- the second SAW resonator 2 b is operating in a high frequency Ri good resonance frequency f r 2, having a capacitive impedance.
- an inductor having an inductive impedance 16 Is required.
- the inductor has a large loss.
- an inductor formed on a dielectric substrate has a Q value of about several tens, and a high Q type such as an air-core coil. , About 1 0 0 Degree is the limit. Therefore, in the configuration using inductors for both the series element and the parallel element of the filter circuit as shown in Fig. 6, there is a problem that the loss in the passband increases when an actual filter circuit is configured. Atsuta.
- the parallel resonance circuit used for the parallel element becomes dominant at frequencies lower than anti-resonance frequency: f ap because the admittance of the inductor is smaller than that of f ap . Indicates sex admittance.
- the admittance of the capacitor 15 is smaller and becomes dominant, and the parallel resonant circuit exhibits capacitive admittance. Therefore, impedance characteristics of the passband of the fill evening circuit away from antiresonance vibration frequency f a p, since the components other than the pure resistance component increases, the difficult problem to realize a low-loss characteristics over a wide band was there.
- Reference 5 Japanese Patent Application Laid-Open No. Hei 9-116680
- Reference 5 Japanese Patent Application Laid-Open No. Hei 9-116680
- Capacitor 15 and inductor 14 connected in parallel.
- the resonance circuit 21 is the same as that shown in FIG. 4, and is essentially no different from a surface acoustic wave resonator. In terms of design, the resonance frequency of the resonant circuit 21 is set to be almost the same as the anti-resonance frequency of the SAW resonator 1 as a parallel element. is there.
- the resonance circuit 21 shown in FIG. Although there is room for broadening the bandwidth by the amount that is not limited, the Q value of the inductor is actually much smaller than the Q value of the surface acoustic wave resonator 2, and the surface acoustic wave is generated by the resonance circuit 21. Even though the characteristics could be broader than resonator 2, it was difficult to achieve low-loss transmission characteristics.
- the Q value of the resonance circuit 21 is small, it is difficult to make the attenuation characteristics on the high frequency side steeper than the passband of the filter circuit formed by the series elements, and the resonance circuit 21 is formed. Also, it is difficult to form a steep zero point for the attenuating pole, and there is a problem that the attenuation characteristics on the higher frequency side than the passband deteriorate.
- the conventional filter circuit is configured as described above, if the frequency of the passband is far from the frequency of the attenuation band, a low-loss and wideband pass characteristic is realized, and a large attenuation over a wideband. There is an issue that is difficult to achieve.
- the present invention has been made to solve the above-described problems, and realizes a low-loss, wide-band pass characteristic even when the pass-band frequency and the attenuation-band frequency are distant from each other, and has a large bandwidth over a wide band.
- the purpose is to obtain a filter circuit that can realize the amount of attenuation. Disclosure of the invention
- a series element is formed by using a resonance element having anti-resonance characteristics
- a parallel element is formed by using a series circuit of an inductor and a capacitor.
- FIG. 1 is a configuration diagram showing a conventional filter circuit.
- FIG. 2 is a configuration diagram showing a specific example of a surface acoustic wave resonator.
- FIG. 3 is a structural diagram showing a specific structure of the surface acoustic wave resonator.
- FIG. 4 is a circuit diagram showing an equivalent circuit of the surface acoustic wave resonator.
- FIG. 5 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- FIG. 6 is a configuration diagram showing a conventional filter circuit.
- FIG. 7 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- FIG. 8 is a configuration diagram showing a conventional filter circuit.
- FIG. 9 is a configuration diagram showing a filter circuit according to Embodiment 1 of the present invention.
- FIG. 10 is a circuit diagram showing an equivalent circuit of the filter circuit in a frequency range in which the surface acoustic wave resonator does not excite surface acoustic waves.
- FIG. 11 is an explanatory diagram for explaining the circuit operation of the filter circuit of FIG.
- FIG. 12 is a configuration diagram showing a specific configuration of the surface acoustic wave resonator.
- FIG. 13 is an explanatory diagram for explaining the transmission characteristics of the surface acoustic wave resonator.
- FIG. 14 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- FIG. 15 is a configuration diagram showing a filter circuit according to Embodiment 2 of the present invention.
- FIG. 16 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- FIG. 17 is an explanatory diagram illustrating the operation of the filter circuit according to Embodiment 3 of the present invention.
- FIG. 18 is a configuration diagram showing a filter circuit according to Embodiment 4 of the present invention.
- FIG. 19 is a circuit diagram illustrating the operation of the filter circuit of FIG.
- FIG. 20 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- FIG. 21 is a configuration diagram showing a filter circuit according to Embodiment 5 of the present invention.
- FIG. 22 is a block diagram showing a filter circuit according to Embodiment 6 of the present invention. It is.
- FIG. 23 is a configuration diagram showing a filter circuit according to Embodiment 7 of the present invention.
- FIG. 24 is a configuration diagram showing a filter circuit according to Embodiment 8 of the present invention.
- FIG. 25 is a configuration diagram showing a filter circuit according to Embodiment 9 of the present invention.
- FIG. 26 is a circuit diagram showing an equivalent circuit in a frequency range in which the surface acoustic wave resonator of the filter circuit of FIG. 25 does not excite surface acoustic waves.
- FIG. 27 is an explanatory diagram explaining the operation of the filter circuit of FIG.
- FIG. 28 is a circuit diagram when a surface acoustic wave resonator is used as a parallel element.
- FIG. 29 is an explanatory diagram showing the pass characteristics of the surface acoustic wave resonator shown in FIG.
- FIG. 30 is an explanatory diagram showing the operation of the filter circuit of FIG.
- FIG. 31 is a configuration diagram showing a filter circuit according to Embodiment 10 of the present invention.
- FIG. 32 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- FIG. 33 is an explanatory diagram showing the operation of the filter circuit according to Embodiment 11 of the present invention.
- FIG. 34 is a configuration diagram showing a filter circuit according to Embodiment 12 of the present invention.
- FIG. 35 is an explanatory diagram showing the operation of the filter circuit of FIG.
- FIG. 36 is a configuration diagram showing a filter circuit according to Embodiment 13 of the present invention.
- FIG. 37 is an explanatory diagram showing the operation of the filter circuit of FIG.
- FIG. 38 shows a configuration of a filter circuit according to Embodiment 14 of the present invention.
- FIG. 39 is an explanatory diagram showing the measurement results of the pass characteristics of the filter circuit of FIG. 38.
- FIG. 40 is an explanatory diagram showing impedance characteristic measurement results of the filter circuit of FIG. 38.
- FIG. 41 is a configuration diagram showing a filter circuit according to Embodiment 15 of the present invention.
- FIG. 42 is an explanatory diagram showing the operation of the filter circuit of FIG.
- FIG. 43 is a circuit diagram showing an equivalent circuit of the filter circuit in a frequency range in which the surface acoustic wave resonator does not excite surface acoustic waves.
- FIG. 44 is a configuration diagram showing a filter circuit according to Embodiment 16 of the present invention.
- FIG. 45 is a circuit diagram showing an equivalent circuit of the filter circuit in a frequency range in which the surface acoustic wave resonator does not excite surface acoustic waves.
- FIG. 46 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- FIG. 47 is a configuration diagram showing a filter circuit according to Embodiment 17 of the present invention.
- FIG. 48 is a configuration diagram showing a filter circuit according to Embodiment 18 of the present invention.
- FIG. 49 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- FIG. 50 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- FIG. 51 is a block diagram showing a filter circuit according to Embodiment 22 of the present invention.
- FIG. 52 is a structural diagram of the interdigital condenser.
- FIG. 53 is a configuration diagram showing a filter circuit according to Embodiment 23 of the present invention.
- FIG. 55 is an explanatory diagram in which the vicinity of the resonance frequency in FIG. 54 is enlarged.
- FIG. 9 is an explanatory diagram showing the measurement results of the pass characteristics in the case.
- FIG. 57 is an explanatory diagram enlarging the vicinity of the resonance frequency in FIG.
- FIG. 58 is a configuration diagram showing a filter circuit according to Embodiment 24 of the present invention.
- FIG. 59 is an explanatory view showing a coil 67 having polystyrene as a core 66.
- FIG. 6 0 The figure shows a coil and a core and polystyrene, using L i N b 0 3 in the evening one digital capacitor formed on a substrate, actually pass characteristics measurement results of case where the fill evening circuitry FIG.
- FIG. 61 is an explanatory diagram in which the vicinity of the resonance frequency in FIG. 60 is enlarged.
- FIG. 62 is a configuration diagram showing a filter circuit according to Embodiment 25 of the present invention.
- Embodiment 1 is a configuration diagram showing a filter circuit according to Embodiment 1 of the present invention.
- reference numeral 2 denotes an elastic surface acoustic wave resonator having an anti-resonance characteristic and constituting a series element.
- Resonant element 3 is the input terminal
- 4 is the input side ground terminal
- 5 is The output terminal
- 6 is the ground terminal on the output side
- 14 is the inductor
- 15 is the capacitor.
- the series circuit of the inductor 14 and the capacitor 15 constitutes a parallel element, forming a 7 ⁇ circuit.
- FIG. 10 shows a frequency range in which the surface acoustic wave resonator 2 does not excite surface acoustic waves, that is, a frequency range lower than the resonance frequency f s of the surface acoustic wave resonator 2
- FIG. 4 is a circuit diagram showing an equivalent circuit of a filter circuit in a frequency range higher than a resonance frequency: f as .
- the surface acoustic wave resonator 2 operates as a capacitor 22 with a capacitance C 2 in a frequency range in which surface acoustic waves are not excited.
- Series resonant circuit with Indaku evening 1 4 and the capacitor 1 5 is a parallel element, series resonance at a frequency f n, i.e., (see first 1 drawing) showing a resonance characteristic.
- f n frequency
- the filter circuit exhibits an attenuation pole and exhibits a large blocking characteristic.
- the pass characteristic shows a rejection characteristic with an extremely steep attenuation pole near the frequency f n , and the cut-off frequency f. It exhibits low loss characteristics in the above frequency range.
- the inductance 14 usually uses an inductance smaller than ⁇ ⁇ ⁇ ⁇ , and the inductance 14 in such an inductance is often used.
- the Q value rarely exceeds 100 at best.
- the resistance component of the inductor 14 is connected in series with the inductor 14, the ratio of the impedance of the inductor 14 to the resistance value of the resistance component is the Q value. Equivalent to.
- Air-core coils have a higher Q value than other inductors.
- the inductance of an inductor composed of conductor lines on the surface of a dielectric substrate is large, about several tens, and less than 10
- capacitors 15 and 22 often use a capacitance smaller than 100 pF in the frequency range used for mobile communications.
- the Q value of the capacitor 15 in the capacitance is about several hundreds.
- the Q value of capacitor 15 is considered as the resistance component connected in parallel to capacitor 15, and the reciprocal of the product of the resistance value of the resistance component and the admittance of capacitor 15 corresponds to the Q value. . Therefore, in the series resonance circuit, the Q value of the inductor 14 has a large effect on the fill characteristic.
- FIG. 11 is an explanatory diagram for explaining the circuit operation of the filter circuit of FIG.
- f n the frequency of the attenuation pole
- the f c is the cutoff frequency.
- Reference numeral 23 denotes the pass characteristic of the circuit shown in FIG. 10 when there is no loss in the inductor 14, the capacitor 15 and the capacitor 22.
- the reference numeral 24 denotes the inductor 14 and the capacitor 15 This is the pass characteristic when the loss of the capacitor 22 is considered.
- FIG. 12 is a configuration diagram showing a specific configuration of the surface acoustic wave resonator 2
- FIG. 13 is an explanatory diagram for explaining a pass characteristic 25 of the surface acoustic wave resonator 2.
- the transmission characteristic 25 as shown in FIG. 13 is exhibited. That is, the surface acoustic wave resonator 2 shows a series resonant characteristic at a frequency f r, shows a parallel resonance characteristic at a frequency f the as.
- the frequency rs is called a resonance frequency, and the frequency: f as is called an anti-resonance frequency.
- the surface acoustic wave resonator 2 is almost short-circuited, so that the passing characteristic 25 shows a low-loss characteristic.
- the surface acoustic wave resonator 2 is almost open, so that the pass characteristic 25 shows an attenuation pole.
- the attenuation pole of the surface acoustic wave resonator 2 should form a steeper attenuation pole than in the case of the series resonance circuit consisting of the inductor 14 and the capacitor 15 as shown in Fig. 11. Can be.
- FIG. 14 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- reference numeral 26 denotes the pass characteristic of the filter circuit of FIG. 9, and the pass characteristic 24 shown in FIG. 11 and the pass characteristic 25 shown in FIG. 13 are superimposed. Can be thought of as
- the surface acoustic wave resonator 2 can form a steep attenuation pole near the anti-resonance frequency f as .
- the frequency difference between the attenuation pole and the resonance frequency f rs of the surface acoustic wave resonator 2 is limited by the electromechanical coupling coefficient k 2 of the piezoelectric material used, and the required frequency difference can be freely provided. Can not. For this reason, there is a limit on the frequency width at which the attenuation pole is equal to or greater than a certain required value.
- the resonance frequency f n of the series circuit of the inductor 14 and the capacitor 15 is set to be near the anti-resonance frequency f as of the surface acoustic wave resonator 2, the pass characteristic 2 shown by the broken line Even if a clear attenuation pole cannot be formed as shown in Fig. 4, the gentle attenuation characteristic is superimposed on the pass characteristic 25 of the surface acoustic wave resonator 2, and the pass characteristic 25 of only the surface acoustic wave resonator 2 is obtained. As compared with the case, the attenuation can be increased.
- the surface acoustic wave resonator 2 has a frequency range higher than the anti-resonance frequency f as , the elastic surface wave hardly excites, and the mere capacitance C 2 is reduced. What is necessary is just to operate as the capacitor 22 which has. For this reason, in a normal surface acoustic wave filter that excites a surface acoustic wave in the passband, if large power is input, the stress associated with the excitation of the surface acoustic wave, In the filter circuit shown in Fig.
- the surface acoustic wave resonator 2 is only damaged by electromigration due to the inflow of a large current, whereas electromigration caused by the inflow of a current causes a breakdown. Therefore, the resistance to higher power operation is higher than that of a conventional surface acoustic wave filter of this type. Furthermore, the frequency f a of the attenuation pole and the cutoff frequency f are independent of the electromechanical coupling coefficient k 2 of the piezoelectric body of the surface acoustic wave resonator 2. Can be set. Compared to the conventional filter circuit using this type of surface acoustic wave, which uses the vicinity of the resonance frequency f rs of the surface acoustic wave resonator 2 as a passband, Can be dramatically increased.
- the capacitor 22 which is the capacitance of the surface acoustic wave resonator 2 has a dielectric loss or an elasticity of the piezoelectric material constituting the surface acoustic wave resonator 2.
- the electrode resistance of the surface acoustic wave resonator 2 affects the Q value.
- Piezoelectric material is often a piezoelectric single crystal, and the dielectric loss is smaller than that of the high dielectric constant dielectric used in the capacitor 15.
- the electrode resistance depends on the design of the surface acoustic wave resonator 2.For example, if a capacitance of 2 pF is required, and if the operating frequency is 900 MHz, the electrode resistance becomes, for example, When 1 ⁇ , the Q value of capacitor 22 is as follows
- FIG. 15 is a configuration diagram showing a filter circuit according to Embodiment 2 of the present invention
- FIG. 16 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- 2a is the first surface acoustic wave resonator
- 2b is the second surface acoustic wave resonator
- 27a is the pass characteristic of the first surface acoustic wave resonator 2a
- 27b is the second surface acoustic wave resonator.
- Reference numeral 2 denotes the pass characteristics of the surface acoustic wave resonator 2b
- reference numeral 28 denotes the pass characteristics of the filter circuit shown in FIG.
- the first surface acoustic wave resonator 2a has a resonance frequency of: s !
- the anti-resonance frequency is: f as !
- the capacitance is C 2.
- the second surface acoustic wave resonator 2 b has a resonance frequency f rs 2 , an anti-resonance frequency f as 2 , and a capacitance C 3 .
- the capacitance C 3 of the surface acoustic wave resonator 2b is substantially the same.
- Anti-resonance frequency f as of first elastic surface wave resonator 2a Is set higher than the anti-resonance frequency: f as 2 of the second surface acoustic wave resonator 2b, and in conjunction with this,
- the inductor 14 and the capacitor 15 near the input terminal 3 and the inductor 14 and the capacitor 15 near the output terminal 5 have substantially the same inductance, capacitance, and capacitance. Further, the inductance of the inductor 14 between the first surface acoustic wave resonator 2a and the second surface acoustic wave resonator 2b is equal to the inductance of the inductor 1 near the input terminal 3. Inductance of 4 Half of Li
- the capacitance of the capacitor 15 between the first surface acoustic wave resonator 2a and the second surface acoustic wave resonator 2b is the same as the capacitance of the capacitor 15 near the input terminal 3. It is twice the capacity (2 C i).
- the configuration shown in FIG. 15 is equivalent to the configuration in which the 7T circuits shown in FIG. 9 are connected in two stages.
- the anti-resonance frequency f as i of the first surface acoustic wave resonator 2a is higher than the resonance frequency f as 2 of the second surface acoustic wave resonator 2b . So that the frequency f as of the attenuation pole created by the first surface acoustic wave resonator 2 a! And the reduction made by the second surface acoustic wave resonator 2 b Attenuation frequency: Since f as 2 is different, large attenuation can be achieved over a wide frequency range.
- the attenuation and the frequency difference between the first and the attenuation pole due to anti-resonance frequency f the as i SAW resonator 2 a, the second SAW resonator 2 b anti-resonance frequency f attenuation pole due to the as 2
- the relationship with the characteristics depends on the electromechanical coupling coefficient of the piezoelectric material used in the first surface acoustic wave resonator 2a and the second surface acoustic wave resonator 2b.
- FIG. 17 is an explanatory diagram illustrating the operation of the filter circuit according to Embodiment 3 of the present invention.
- the circuit configuration of the filter circuit that operates as shown in Fig. 17 is the same as that of the filter circuit in Fig. 15; the inductor 14, the capacitor 15, and the first surface acoustic wave resonance.
- capacitance vessels 2 a C 2 cut-off frequency f which is determined by the capacitance C 3 of the second elastic sheet surface wave resonator 2 b.
- the values of each element are determined so that n is the same in all sections, as in the case of FIG. 16.
- the frequency f n of the attenuation pole is changed to the anti-resonance frequency f as of the first surface acoustic wave resonator 2a.
- the first The frequency is set lower than the anti-resonance frequency f a 2 of the surface acoustic wave resonator 2 b of FIG.
- Anti-resonance frequency f as of first surface acoustic wave resonator 2a The frequency difference between the attenuation pole due to and the anti-resonance frequency f as 2 of the second surface acoustic wave resonator 2 b depends on the electromechanical coupling coefficient of the piezoelectric material used. The value obtained by multiplying the frequency by the electromechanical coupling coefficient k 2 is a practical value of the frequency difference. However, as shown in FIG. 17, as shown in FIG.
- the inductance C 14, the capacitor 15 the capacitance C 2 of the first surface acoustic wave resonator 2 a, the capacitance C 2 of the second surface acoustic wave resonator 2 b By setting the frequency f n of the attenuation pole determined by the capacitance C 3 in a frequency range lower than the anti-resonance frequency of the second surface acoustic wave resonator 2 b: f a 2 , a wider range can be obtained. Large attenuation can be obtained in the range.
- the frequency f n of the attenuation pole is independent of the characteristics of the first surface acoustic wave resonator 2 a and the second surface acoustic wave resonator 2 b as a surface acoustic wave resonator. Greater freedom of design because it can be set.
- Out-of-band characteristics in the frequency range close to are mainly achieved by using the attenuation poles of the first surface acoustic wave resonator 2a and the second surface acoustic wave resonator 2b. it can.
- a lower frequency range than the attenuation pole of the second SAW resonator 2 b is Inda Kuta 1 4, capacitor 1 5, the capacitance C 2 of the first SAW resonator 2 a, the second A large amount of attenuation can be obtained over a wide frequency range by using the attenuation pole of the frequency f n determined by the capacitance C 3 of the surface acoustic wave resonator 2b.
- the attenuation pole at frequency f n has a cut-off frequency of f, especially because the Q value of inductor 14 is small. In the vicinity of, it is difficult to obtain a sharp attenuation characteristic, but the cutoff frequency is e. The greater the frequency difference from the frequency, the greater the attenuation characteristics over a wider frequency range.
- FIG. 18 is a configuration diagram showing a filter circuit according to Embodiment 4 of the present invention.
- the circuit configuration of the filter circuit is the same as that of the filter circuit in Fig. 15, but the filter circuit in Fig. 18 changes the element values of the inductor 14 and the capacitor 15 for each section. Changing.
- FIG. 19 is a circuit diagram illustrating the operation of the filter circuit of FIG.
- a first L-shaped circuit comprising a first elastic and part of the surface wave resonator 2 a of the capacitance C 2, and b Ndaku evening 14 close to the input terminal 3 capacitor 1 5 which Is shown.
- 29 b is a part of the capacitance C 2 of the first surface acoustic wave resonator 2 a and between the first surface acoustic wave resonator 2 a and the second surface acoustic wave resonator 2 b.
- An L-shaped circuit consisting of a certain inductor 14 and a part of each of the capacitors 15, a part of the capacitance C 3 of the second surface acoustic wave resonator 2 b, and the first surface acoustic wave resonance
- a first T-shaped circuit combining an L-shaped circuit consisting of the inductor 14 and a part of the capacitor 15 between the resonator 2a and the second surface acoustic wave resonator 2b Is shown.
- 29 c is a part of the capacitance C 3 of the second surface acoustic wave resonator 2 b and a second L-shaped circuit composed of a capacitor 14 and a capacitor 15 at the output terminal 5.
- the element values in the first L-shaped circuit, the first T-shaped circuit, and the second L-shaped circuit shown in Fig. 19 are the same as those in the filter circuit in Fig. 18. There is the following relationship.
- the cutoff frequency f of each section of the first L-shaped circuit, the first T-shaped circuit, the second L-shaped circuit, and the like are set to the same value, even if different attenuation pole frequencies are set for each section, these sections are connected in cascade to achieve a characteristic in which the pass characteristics of each section are superimposed. it can. Design techniques for such filter circuits are widely known.
- FIG. 20 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- 30a is the pass characteristic of the first L-type circuit
- 30b is the pass characteristic of the first T-type circuit
- 30c is the pass characteristic of the second L-type circuit
- 31 is the first Figure 8 shows the pass characteristics of the filter circuit.
- f as 2 is set lower than the pass band of the filter circuit
- the anti-resonance of the first surface acoustic wave resonator 2a is set.
- Frequency f a s ! Is set higher than the anti-resonance frequency f as 2 of the second surface acoustic wave resonator 2b.
- the attenuation pole frequency f n i of the first L-shaped circuit, the attenuation pole frequency f ⁇ 2 of the first T-shaped circuit, and the attenuation pole frequency f n 3 of the second L-shaped circuit are all expressed as The frequency is lower than the anti-resonance frequency f as 2 of the second surface acoustic wave resonator 2 b, and the frequency f n of the attenuation pole of the first L-shaped circuit! ,
- the first frequency f n 2 of the attenuation pole of the T-shaped circuit, different frequencies frequency f n a of the attenuation pole in the second L-shaped circuit With such a configuration, a large amount of attenuation can be obtained in an extremely wide range.
- FIG. 21 is a block diagram showing a filter circuit according to Embodiment 5 of the present invention. It is.
- the circuit configuration of the filter circuit shown in Fig. 21 is the same as that shown in Fig. 9 except that the connection order of the inductor 14 and the capacitor 15 is different. If the same element values as those in the figure are used, the characteristics are the same as those shown in FIG. However, unlike the case of FIG. 9, FIG. 21 shows that two capacitors 15 are formed on the same chip 32 as the surface acoustic wave resonator 2.
- the piezoelectric material used in the surface acoustic wave resonator 2 or the like often has a dielectric constant of several tens or more, and is also useful as a high dielectric substrate.
- the pattern of IDT 9 as shown in FIG. 3 operates as a single capacitor at a frequency that does not excite surface acoustic waves, so that the IDT 9 has a frequency that is significantly different from the antiresonant frequency of surface acoustic wave resonator 2. By forming 9, capacitor 15 can be realized.
- FIG. 22 is a block diagram showing a filter circuit according to Embodiment 6 of the present invention, in which 33 is a short stub in which one side of the distributed constant line is grounded.
- the dependency matrix of the distributed constant line for the characteristic impedance Z and electric length S is given by the following equation. cos ⁇ jz mO
- the electrical length ⁇ has the following relationship from the wave number k and the line length D.
- a short stub with one terminal grounded has an impedance Z s of j ⁇ ta ⁇ ⁇ , so in the range where 6> is small, the short stub impedance Z s should be considered as follows: Can be.
- Equation (11) shows that this kind of shot-stop operates approximately as an inductance of the inductance (ZD / c), which has been explained so far.
- the same effect can be obtained by replacing the inductor 14 in the filter circuit with the short stub 33.
- a distributed constant line such as a short stub may be formed as a line pattern on a dielectric substrate when a filter circuit is formed on a dielectric substrate.
- a filter circuit can be incorporated into a more complicated circuit.
- FIG. 23 is a configuration diagram showing a filter circuit according to Embodiment 7 of the present invention, in which 34 is an open stub.
- Open stub This is a distributed parameter line with one terminal open, and impedance Z in this case. Is given by the following equation.
- FIG. 24 is a block diagram showing a filter circuit according to Embodiment 8 of the present invention.
- reference numeral 35 denotes a spiral open stub.
- the open stub 35 does not necessarily have to be a linear distributed constant line, and a spiral shape effectively increases the magnetic flux generated by the electromagnetic field propagating through the line, because the spiral 3.5 itself effectively enhances the magnetic flux. than when using a linear open scan evening Bed 3 4, certain advantages force s can achieve the same characteristics in a small area Ri good.
- Embodiment 9 Embodiment 9
- FIG. 25 is a configuration diagram showing a filter circuit according to Embodiment 9 of the present invention.
- a surface acoustic wave resonator 1 is used as a parallel element, and a parallel circuit of an inductor 14 and a capacitor 15 is used as a series element.
- Fig. 26 shows the surface acoustic wave resonator 1 of the filter circuit of Fig. This is an equivalent circuit in a frequency range where no wave is excited.
- FIG. 27 is an explanatory diagram for explaining the operation of the filter circuit of FIG. Series elements Phil evening circuit of the second 6 diagram, the parallel resonance at a frequency f n, that is, the anti-resonance.
- the impedance of the series element existing in the path from the input terminal 3 to the output terminal 5 is open, and the pass characteristic 36 from the input terminal 3 to the output terminal 5 indicates an attenuation pole. Shows large attenuation characteristics.
- the actual inductor 14 and the capacitor 15 have a loss component.
- the Q value of the inductor 14 rarely exceeds 100 at a frequency near GHz. It is about 50 to 80.
- the attenuation characteristic deteriorates so that the attenuation pole does not show a clear zero point, and the cutoff frequency: f.
- the loss in the passband on the lower frequency side also increases.
- FIG. 28 is a circuit diagram when the surface acoustic wave resonator 1 is a parallel element.
- FIG. 29 is an explanatory diagram showing the pass characteristics of the surface acoustic wave resonator 1 shown in FIG.
- 3 8 if was a surface acoustic wave resonator 1 is a pass characteristic of the surface acoustic wave resonator 1 and parallel elements, since the surface acoustic wave resonator 1 at the resonance frequency f P p is short, A large attenuation pole is formed in the transmission characteristics.
- FIG. 30 is an explanatory diagram showing the operation of the filter circuit of FIG. 25.
- 39 is a pass characteristic of the filter circuit of FIG.
- the anti-resonance frequency f n resonance frequency fpp and series elements of the surface acoustic wave resonator 1 is set to a remote high frequency by the cut-off frequency fc. Under these conditions, in the pass band, surface acoustic wave resonance W
- the device 1 Since the frequency of the device 1 is lower than the resonance frequency f rp , the device 1 can be operated without exciting the surface acoustic wave. For this reason, in a normal SAW-filled surface acoustic wave resonator that excites surface acoustic waves in the passband, when large power is input, stress migration accompanying the excitation of surface acoustic waves, Destruction occurs due to electromigration caused by the inflow of a large current, whereas in the filter circuit shown in Fig. 25, the surface acoustic wave resonator 1 uses the electromigration caused by the inflow of a large current. Since only destruction is a problem, the resistance to higher power operation is higher than that of conventional surface acoustic wave filters of this type.
- the passband or cutoff frequency f When the frequency difference between the resonant frequency p of the surface acoustic wave resonator 1, the cut-off frequency to the electromechanical coupling coefficient k 2 of the piezoelectric body used in the surface acoustic wave resonator 1: f e or surface acoustic wave resonator 1 even also a value greater than value obtained by multiplying the resonance frequency f P p, it is possible to obtain a good full I le evening characteristics.
- the pass characteristic 39 of the filter circuit in Fig. 25 is a characteristic obtained by superimposing the pass characteristic 37 of the filter circuit in Fig. 26 and the pass characteristic of the surface acoustic wave resonator 1 shown in Fig. 28. is there.
- a steep attenuation characteristic cannot be obtained in the vicinity of the pass band, but a steep attenuation characteristic formed near the resonance frequency f ⁇ ⁇ ⁇ of the surface acoustic wave resonator 1 is obtained. With the attenuation pole, good attenuation characteristics can be obtained.
- FIG. 31 is a configuration diagram showing a filter circuit according to Embodiment 10 of the present invention.
- FIG. 32 is an explanatory diagram for explaining the operation of the filter circuit of FIG. 31.
- the circuit configuration of the filter circuit shown in FIG. 31 is the same as that of the filter circuit shown in FIG. 25, but the resonance frequencies of the two surface acoustic wave resonators 40 are different from each other. The values are different.
- the anti-resonance frequency of the parallel circuit of the capacitor 1 5 and f n, with respect to the cut-off frequency fc, and Unishi by satisfying the following relationship.
- FIG. 33 is an explanatory diagram showing the operation of the filter circuit according to Embodiment 11 of the present invention.
- the circuit configuration of the filter circuit is the same as that of the filter circuit of FIG. 31.
- the resonance frequency f p i of the first surface acoustic wave resonator 40a and the second surface acoustic wave resonator The same applies when the resonance frequency f rp 2 of 40 b is set to a different frequency, but the anti-resonance frequency f n of the parallel circuit of the inductor 14 and the capacitor 15 is changed to the first surface acoustic wave.
- Resonator 40 a Resonance frequency f r p! And also Ri good resonance frequency f r p 2 of the second surface acoustic wave resonator 4 0 b is set to a higher frequency.
- the cutoff frequency f. Is obtained by the attenuation pole formed by the first surface acoustic wave resonator 40a and the second surface acoustic wave resonator 40b, and the first surface acoustic wave
- the attenuation characteristic at a higher frequency than the attenuation pole formed by the resonator 40a and the second elastic surface acoustic wave resonator 40b is the anti-resonance frequency of the parallel circuit of the inductor 14 and the capacitor 15 It is obtained by the attenuation pole near f n '. Inductor 14 and capacitor 15
- the attenuation pole of the column circuit is the cutoff frequency f. Since it is easier to obtain a larger amount of attenuation over a wide frequency range as the distance from the antenna increases, better attenuation characteristics can be obtained over a wider frequency range than that shown in FIG. Embodiment 1 2
- FIG. 34 is a configuration diagram showing a filter circuit according to Embodiment 12 of the present invention.
- a second parallel element 43b and a third surface acoustic wave resonator 40c are added.
- FIG. 35 is an explanatory diagram showing the operation of the filter circuit of FIG. In the figure, 45 is the pass characteristic of the filter circuit of FIG.
- an equivalent circuit in the frequency range where the surface acoustic wave resonator 40 does not excite surface acoustic waves shows a plurality of L-shaped circuits, similar to the filter circuit shown in Fig. 19.
- FIG. 36 is a configuration diagram showing a filter circuit according to Embodiment 13 of the present invention
- FIG. 37 is a diagram for explaining the operation of the filter circuit of FIG. You.
- 46a is the first surface acoustic wave resonator
- 46b is the second surface acoustic wave resonator
- 47 is the inductor
- 48 is the capacitor
- 49 is the series resonant circuit
- 50 a is the pass characteristic of the first surface acoustic wave resonator 46 a
- 50 a is the pass characteristic of the second surface acoustic wave resonator 46 b
- 51 is the fill of FIG. 36 This is the passing characteristic of the evening circuit.
- the first surface acoustic wave resonator 46 a has a resonance frequency f fsl , an anti-resonance frequency f asl , and a capacitance C 2 .
- the second surface acoustic wave resonator 46 b has a resonance frequency f rs 2 , an anti-resonance frequency f as 2 , and a capacitance C 3 .
- First surface acoustic wave resonator 4 6 a capacitance C 2 and the capacitance C 3 of the second surface acoustic wave resonator 4 6 b of is almost the same value.
- the anti-resonance frequency f as i of the first surface acoustic wave resonator 46 a is set higher than the anti-resonance frequency f as 2 of the second surface acoustic wave resonator 46 b, and is linked to this.
- the resonance frequency f PSi of the first surface acoustic wave resonator 46 a is higher than the resonance frequency f PS 2 of the second surface acoustic wave resonator 46 b.
- the inductance 47 and the capacitor 48 near the input terminal 3 and the inductance 47 and the capacitor 48 near the output terminal 5 have the same inductance and capacitance, respectively.
- the inductance of the inductor 47 between the surface acoustic wave resonator 46a and the second surface acoustic wave resonator 46b is the inductance of the inductor 47 near the input terminal 3. It is half of L1.
- the capacitance of the capacitor 48 between the first surface acoustic wave resonator 46a and the second surface acoustic wave resonator 46b is the static capacitance of the capacitor 48 near the input terminal 3. It is twice the capacitance.
- Inductor 47 and capacitor 48 which are parallel elements, capacitance C2 of first surface acoustic wave resonator 46a, and capacitance C2 of second surface acoustic wave resonator 46 3.
- the cut-off frequency determined by: f.
- the element values are determined so that the frequencies f n of the attenuation poles are all in the same section.
- the frequency f n of the attenuation pole changes due to changes in the inductance of the inductor 47 and the capacitance of the capacitor 48.
- the inductance of the inductor 47 and the capacitance of the capacitor 48 usually include an error within ⁇ several percent.
- the frequency of the attenuation pole: n fluctuates due to the elements constituting the filter circuit, and the frequency f n of the attenuation pole cannot be set to a desired frequency, and the surface acoustic wave resonator 46 a Frequency higher than the anti-resonance frequency f as Alternatively, the anti-resonance frequency of the surface acoustic wave resonator 46 b becomes lower than f as 2 , and a sufficient attenuation characteristic may not be obtained as a filter circuit.
- the anti-resonance frequency of the first surface acoustic wave resonator 46a f asl is changed from the desired frequency to the inductance of the inductor 47 and the electrostatic capacitance of the capacitor 48 .
- the second surface acoustic wave resonator 4 6 b of the anti-resonance frequency a the as 2, Ri by a desired frequency, Lee Ndaku evening 4 7 Lee emission duct evening Manual and frequency variation due to attenuation pole of the capacitance of the capacitor 4 8: set to as low a frequency f n variation.
- Anti-resonance frequency f as i of first surface acoustic wave resonator 46 a and second elastic Anti-resonance frequency of the surface wave resonator 4 6 b the e the as 2 by setting so as to satisfy the above relationship, even Ratsui If the element values of the inductors evening 4 7 and the capacitor 4 8, the capacitor 4 8 frequency f n of the attenuation pole is determined by the first surface acoustic wave resonator 4 6 a static Den'yo amount C 2 and the capacitance C 3 of the second surface acoustic wave resonator 4 6 b is a surface acoustic Since it is between the anti-resonance frequency f asi of the wave resonator 46 a and the anti-resonance frequency f as 2 of the surface acoustic wave resonator 46 b, good attenuation characteristics can be obtained.
- FIG. 38 is a block diagram showing a filter circuit according to Embodiment 14 of the present invention, in which 52 is a capacitor.
- First surface acoustic wave resonator 4 6 a is antiresonance frequency is f as E, the capacitance is C 2.
- the second surface acoustic wave resonator 4 6 b anti-resonant frequency is: a f the as 2, the electrostatic capacity is C 3.
- the capacitance C 2 of the first surface acoustic wave resonator 4 6 a capacitance C 3 of the second surface acoustic wave resonator 4 6 b is substantially the same value.
- the capacitance of the capacitor 52 is C 4
- the inductance of the inductor 47 is
- the capacitance of the capacitor 48 is 2 Ci.
- the series element shown in Fig. 9 is composed of the surface acoustic wave resonators 46a and 46b, and the parallel element is composed of the inductor 47 and the capacitor 48.
- This is equivalent to a configuration in which a 7 ° circuit consisting of a resonant circuit is converted to a T-type circuit, the above-mentioned T-type circuits are connected in two stages, and at least one of the series surface acoustic wave resonators is replaced with a capacitor. .
- Fig. 39 shows the experimental results of the pass characteristics of the filter circuit of Fig. 38 actually created
- Fig. 40 shows the experimental results of the impedance characteristics.
- 5 1 & is 1 ⁇ 2 2 4 1111
- 2 C 1 24 pF
- the filter circuit shown in Fig. 38 shows the same filter characteristics as the filter circuit shown in Fig. 36, and it is possible to realize good attenuation characteristics over a wide frequency range and to have good pass characteristics. Can be.
- FIG. 41 is a diagram showing a filter circuit according to Embodiment 15 of the present invention.
- reference numeral 46c denotes a surface acoustic wave element, which is used as a series element.
- 47a is an inductor and 48a is a capacitor, forming a series resonant circuit (hereinafter referred to as a series resonant circuit A) of parallel elements.
- 47 c is an inductor connected in parallel.
- FIG. 42 is a diagram for explaining the operation of the filter circuit shown in FIG. 50 c is the pass characteristic of the surface acoustic wave element 46 c, 49 a is the pass characteristic of the series resonance circuit A, and 57 is the pass characteristic of the filter circuit of FIG.
- the surface acoustic wave element 46 c has a very steep attenuation characteristic at the frequency: as as shown by the passing characteristic 50 c in FIG.
- this attenuation characteristic is steep, it is difficult to obtain large attenuation over a wide band. It is difficult.
- the series resonant circuit A formed by Lee Ndaku evening 4 7 a and the capacitor 4 8 a is Ri Do substantially short circuit at the frequency f n to be a series resonance, which reflects most of the input RF signal.
- the series resonance circuit A has a transmission characteristic that greatly attenuates as shown by the transmission characteristic 49a in FIG.
- the inductor 47a normally uses an inductance smaller than 100 nH In many cases, the Q value of the inductor 47a in such an inductance rarely exceeds 100 at best.
- the capacitor 48a often uses a capacitance smaller than 100 pF in a frequency range used in mobile communication, and the Q value of the capacitor 48a at such a capacitance is often used. Is about several hundred. Therefore, in the series resonance circuit A, the Q value of the inductor 47a becomes dominant.
- the Q value of the inductor 47a is about 100 at best, and is smaller than the Q value of the surface acoustic wave element 1. Therefore, the attenuation characteristic of the series resonant circuit A is the pass characteristic. It is not so steep as shown in a.
- the elastic surface wave element 46 is large over a wide band at the frequency f n . It is possible to realize a steep attenuation characteristic caused by c. Also, the inductor 47c plays a role of matching the impedance of the passband. At frequencies higher than the attenuation range, the surface acoustic wave device 46c exhibits a capacitive effect and acts as a capacitor.
- the circuit in Fig. 41 is equivalent to Fig. 43, and adopts a general wide-pass filter configuration. Therefore, by selecting the element values of the surface acoustic wave element 46c, the series resonance circuit, and the inductor 47a so that matching can be achieved at the desired frequency, low-pass characteristics over a wide band can be obtained. Can be realized.
- FIG. 44 is a configuration diagram showing a filter circuit according to Embodiment 16 of the present invention, in which 47 b is an inductor and 48 b is a capacitor.
- the surface acoustic wave resonator 46 b has a resonance frequency f rs 2 , an anti-resonance frequency f a 2 , and a capacitance C 3 .
- SAW resonator 4 6 a in the frequency range not excite surface acoustic waves, operates as a capacitor of the capacitance C 2, the surface acoustic wave resonator 4 6 b in the frequency range not excite surface acoustic wave , that runs as an electrostatic capacitance C 3.
- the first L-shaped circuit consisting of an inductor 47a and a capacitor 48a in parallel, and a capacitor 52a in series
- the parallel element Inductor 47b, capacitor 48b, T-type circuit consisting of capacitors 52a and 52b in series
- parallel element consisting of inductor 47c and series in capacitor 52b
- FIG. 46 is an explanatory diagram for explaining the operation of the filter circuit of FIG. 44.
- 49a is the inductor 47a, capacitor 48a, and capacitor 52 of FIG.
- the pass characteristic of the L-shaped circuit composed of a and the pass characteristic of the T-type circuit composed of the inductor 47b, capacitor 48b, and capacitors 52a and 52b are superimposed.
- b is the pass characteristic of the L-shaped circuit composed of the inductor 47 c and the capacitor 52 b in Fig. 45
- 50 & is the pass characteristic of the first surface acoustic wave resonator 46 a
- 50 b Is the pass characteristic of the second surface acoustic wave resonator 46b
- 51 is the pass characteristic of the filter circuit of FIG.
- the pass characteristics 51 of the filter circuit in FIG. 44 are the pass characteristics 50 a of the first surface acoustic wave resonator 46 a and the pass characteristics 50 a of the second surface acoustic wave resonator 46 b. b and the pass characteristics 49 a and 49 b of the filter circuit of FIG. 45 are superimposed, and the anti-resonance frequency of the first surface acoustic wave resonator 46 a: f as !
- the steep attenuation pole formed near the anti-resonance frequency f as 2 of the second surface acoustic wave resonator 46 b makes it possible to obtain a high-pass filter characteristic with good attenuation characteristics. it can.
- FIG. 47 is a block diagram showing a filter circuit according to Embodiment 17 of the present invention, in which 54 is a transmission line, 55 is a filter circuit B, and its pass band is a filter circuit.
- Circuit A surface acoustic wave resonators 46a and 46b, inductors 47a to 47c, capacitors 48a and 48b) in the attenuation range, and the attenuation range It has in the passing area of A.
- the filter circuit A the series resonant circuit consisting of the inductor 47a and the capacitor 48a is almost short-circuited to ground in the attenuation band. Therefore, the impedance of the filter circuit A as viewed from the transmission line 54 is also substantially at the short-circuit position. Since the transmission line 54 has an electric length corresponding to about / 4 in the attenuation band, the phase rotation causes the filter circuit A side to be seen at the base of the filter circuit B 55. The impedance is generally open. Therefore, the filter circuit A side has almost no effect on the pass characteristics of the filter circuit B 55 (the attenuation band of the filter circuit A corresponds to the pass band of the filter circuit B 55).
- the filter circuit B 555 has almost no effect on the pass characteristics of the filter circuit A by designing the impedance so that it appears open in its own attenuation band. You can do so.
- Embodiment 18 As described above, by connecting the filter circuit A and the filter circuit B 55 via the transmission line 54 as shown in FIG. 47, it is possible to obtain a low-loss, wide-band demultiplexer. it can.
- Embodiment 18
- FIG. 48 is a configuration diagram showing a filter circuit according to Embodiment 18 of the present invention.
- the filter circuit of FIG. 48 has a configuration in which the transmission line 54 is replaced by a filter circuit 56 in the filter circuit of FIG.
- Filler circuit 56 is composed of inductor 56a, 56b and capacitor 56c.
- the impedance when viewing the filter circuit A side at the base of the filter circuit B 55 is almost open, so that the same effect as in the embodiment 17 is obtained. Play.
- the frequency shown in Fig. 17: f a ! can be wider, and a filter circuit with good temperature stability can be obtained.
- the pass loss of the filter circuit that uses a frequency range higher than the anti-resonance frequency of the surface acoustic wave resonator as a pass band can be made particularly low.
- the surface acoustic wave resonator according to the embodiment described above includes, for example, 45. 75 ° rotation from rotating Y-cut Y-cut X-propagating potassium niobate (0 Y
- potassium niobate such as X-KNb03
- a piezoelectric material When potassium niobate such as X-KNb03 is used as a piezoelectric material, it has a very large electromechanical coupling coefficient exceeding 30% and a zero temperature coefficient near room temperature. So, for example, the frequency f as shown in Fig. 17 and Fig. 33 !
- the frequency interval of the attenuation pole from (frequency f r p 1 ) to frequency f as 2 (frequency: f P p 2) can be made wider, and at the same time, characteristics with excellent temperature stability can be obtained. Can be.
- Nio Busanka Li um so also have very high electromechanical binding coefficient as the piezoelectric body for bulk waves, for example, the frequency f a s shown in the first 7 illustrations and 3 3 Figure!
- the frequency interval of the attenuation pole from (frequency: r p!) To frequency f as 2 (frequency: f rp 2 ) can be made wider
- the elastic wave resonator according to the embodiment described above includes, for example, zinc oxide.
- the electromechanical coupling coefficient is equivalent to that of lithium tantalate, and it can be formed on a semiconductor substrate. And can be realized in one.
- the electromechanical coupling coefficient is equivalent to lithium tantalate or zinc oxide, and Since it can also be formed on a substrate, a filter circuit with excellent characteristics can be integrated with a semiconductor element. Furthermore, since the propagation speed of elastic waves is higher than that of zinc oxide or the like, it is suitable for realizing higher frequency elastic wave devices.
- the elastic wave resonator according to the embodiment described above includes, for example, titanic acid.
- lead a (P b T i 0 3) as the piezoelectric Ri also der to obtain an electromechanical coupling coefficient greater than 1 0%,
- the lead titanate is chemically stable, normal air Even when hermetic sealing is required, the fill circuit can be configured without hermetic sealing. Therefore, it is possible to realize a low-cost, high-performance fill circuit.
- the elastic wave resonator according to the embodiment described above uses a piezoelectric material, but is not limited to this.
- a piezoelectric material such as silicon oxide (Si SX) may be used. The effect is the same even when a resonant element using vibration caused by static electricity is used.
- a surface acoustic wave resonator is used, the present invention is not limited to this.
- a bulk wave using thickness longitudinal vibration, thickness shear vibration, or the like is used.
- a resonator may be used.
- the electromechanical coupling coefficient of a surface acoustic wave is larger in the case of a bulk wave than in the case of a surface acoustic wave.
- the frequency f rp ! The frequency interval of the attenuation pole from to the frequency: p 3 can be made wider.
- a surface acoustic wave is, for example, 36 ° other than a pure surface acoustic wave such as a Rayleigh wave or an SH wave that concentrates and propagates elastic energy on a surface.
- rotation Y Chikara' preparative X propagation Yun'yuru lithium (3 6 YX- L i T a 0 3) used as such in, energy to leak surface acoustic wave or near the surface that propagates while lose elastic energy little by little
- elastic waves using SSBW that propagate while concentrating lugi Embodiment 19
- Embodiments 1 to 18 achieve low-loss, wide-band pass characteristics and a large amount of attenuation over a wide band even if the pass-band frequency and the attenuation-band frequency are separated. However, when the environmental temperature changes, it was difficult to guarantee low-loss and wide band pass characteristics and large attenuation over a wide band.
- the temperature range of the usage environment is set, and electrical performance must be guaranteed within that temperature range.
- the element values of the inductor 14 and the capacitor 15 that make up the filter circuit change, and the resonance frequency fluctuates. O The electrical performance could not be guaranteed within the operating temperature range.
- Embodiment 19 is as follows.
- FIG. 49 is an explanatory diagram for explaining the operation of the filter circuit of FIG. 10.
- reference numeral 61a denotes an inductor constituting the filter circuit of FIG. 4. This is the pass characteristic when the losses of capacitors 15 and 22 are considered.
- the resonant frequency is f T.
- ⁇ T be the temperature difference from a certain reference temperature T
- ⁇ L be the amount of change in the inductance of the inductor 14 due to the temperature difference ⁇ T i
- the amount of change of the capacitor accompanying 1 is AC ⁇ , at the changed temperature T + ⁇ i
- the resonance frequency of the series circuit consisting of the inductor 14 and the capacitor 15: i is better than the resonance frequency f r ⁇ at the temperature T. Lower frequency, and the resonance characteristic is 61b.
- the resonance frequency f 2 of the series circuit consisting of the inductor 14 and the capacitor 15 is higher than the resonance frequency f r ⁇ at the temperature T.
- the resonance characteristic is 61 c.
- FIG. 50 is an explanatory diagram for explaining the operation of the filter circuit of FIG.
- 62a is a pass characteristic at the reference temperature T when the losses of the inductor 14, the capacitor 15 and the capacitor 22 constituting the filter circuit of FIG. 26 are considered.
- the anti-resonance frequency is f a T.
- ⁇ T i be the temperature difference from a certain reference temperature T
- ⁇ ⁇ ⁇ ⁇ be the change in the inductance of the inductor 14 due to the temperature difference ⁇ T, ⁇ ⁇ ⁇ , and the temperature difference ⁇ ⁇ !
- ⁇ ⁇ be the amount of change in the capacitor associated with ⁇ , ⁇ ⁇ ⁇ changed temperature ⁇ + ⁇ T i
- the anti-resonance frequency of the filter circuit in FIG. 26 is the anti-resonance frequency at temperature T : The frequency is lower than f a T , and the resonance characteristic is 62b.
- the anti-resonance frequency f T moves to the lower frequency side.
- the anti-resonance frequency of the filter circuit shown in Fig. 26: f & ⁇ ⁇ 2 is the anti-resonance frequency f at the temperature ⁇
- the frequency is higher than r T and the resonance characteristics are 62 c.
- the resonance frequency f r of the Yi Ndaku evening 1 4 and the capacitor 1 5 or Ranaru resonant circuit can be expressed by the following equation.
- Equation (24) is converted to C! Differentiating with respect to yields equation (25).
- Embodiment 22 if the filter circuits of Embodiments 19 and 20 are configured so that equation (26) holds, it is possible to obtain a filter circuit in which the resonance frequency does not fluctuate with temperature change, and low loss Thus, a wide band pass characteristic and a large attenuation over a wide band can be realized. Therefore, electrical performance can be guaranteed without being affected by the environmental temperature.
- Embodiment 22 if the filter circuits of Embodiments 19 and 20 are configured so that equation (26) holds, it is possible to obtain a filter circuit in which the resonance frequency does not fluctuate with temperature change, and low loss Thus, a wide band pass characteristic and a large attenuation over a wide band can be realized. Therefore, electrical performance can be guaranteed without being affected by the environmental temperature.
- Embodiment 22 Embodiment 22.
- FIG. 51 is a configuration diagram showing a filter circuit according to Embodiment 22 of the present invention.
- the configuration of the filter circuit of FIG. 51 is basically the same as the configuration of the filter circuit of FIG. 9 in the first embodiment, except that the capacitor 15 is formed on a piezoelectric substrate. The difference is that it is a digital capacitor.
- Fig. 52 shows the structure of the interdigital condenser.
- the interdigital capacitor shown in Fig. 52 has the same structure as IDT 9 in Fig. 3.
- the IDT 9 operates as a simple capacitor at a frequency at which surface acoustic waves are not excited, the IDT 9 having a frequency that is significantly different from the anti-resonance frequency of the surface acoustic wave resonator 2 can be used. Digital capacitors can be realized.
- This type of IDT 9 pattern can form an accurate pattern, so that the capacitance can be obtained with higher precision than when a normal chip capacitor or the like is used.
- the interdigital capacitor can be formed smaller than the chip capacitor, the effect of reducing the size of the filter circuit can be obtained.
- the configuration of the filter circuit in FIG. 51 has been described.
- the present invention is not limited to this.
- FIG. 53 is a configuration diagram showing a filter circuit according to Embodiment 23 of the present invention. However, in Fig. 53, an air core coil is used to construct the inductor 14. .
- the capacitor 1 5 when the fin evening one di digital capacitors formed on L i Nb 0 3 used ku yo as the piezoelectric substrate, the variation delta C of the electrostatic capacitance caused by temperature changes delta T is It has a positive sign. On the other hand, the amount of change L in the inductance of the air core coil due to the temperature change ⁇ has a negative sign.
- FIG. 55 is an enlarged view of the vicinity of the resonance frequency in FIG. 54. Fluctuation of resonance frequency due to temperature change I fr 25 — fr 75 I is about 15 MHz, which fluctuates to lower frequencies.
- 5 6 figures a full I le evening circuit according to the second to the third embodiment of the present invention, by using a Lee down evening one di digital capacitors formed on Sorashinko I le a L i N b 0 3 substrate, actual 7 shows the measurement results of the transmission characteristics in the case of the configuration shown in FIG.
- 64 a is the pass characteristic measured with the filter circuit kept at 25 ° C.
- fr 25 is the resonance frequency of the parallel element.
- 6 4 b is a pass characteristic measured by keeping the temperature of the full I le evening circuit ⁇ 5 ° C
- f r 7 5 is resonant frequency of the parallel elements.
- FIG. 57 is an enlarged view of the vicinity of the resonance frequency in FIG. Fluctuation of resonance frequency due to temperature change I fr 25 — fr 75 I is about 10 MHz, which fluctuates to lower frequencies.
- fluctuations in the resonance frequency can be made smaller than when a filter circuit is configured using a chip coil.
- the resonance frequency is set to be lower than the anti-resonance frequency of the surface acoustic wave resonator 2 so that the resonance frequency composed of the coil and the capacitor can be confirmed.
- the same effect can be obtained, so that low loss, wide band pass characteristics and large attenuation over a wide band can be realized regardless of temperature changes, and electrical performance can be guaranteed regardless of environmental temperature .
- FIG. 58 is a configuration diagram showing a filter circuit according to Embodiment 24 of the present invention.
- the coefficient of linear expansion is about 380 ppm / ° C.
- Inductor 14 is constructed using a coil with a polystyrene core.
- Fig. 59 shows a coil 67 with the above polystyrene as the core 66.
- the inductance L of Indak Yu is, for example, the following: Literature: Electromagnetism, published by Kyoritsu Shuppan, Yasuharu Suematsu, 1st edition of 1980, 1975, pp. 206 to 20 7 (hereinafter referred to as reference 6), it can be expressed by the following equation (2 7).
- a core 67 having a core 66 of polystyrene having a linear expansion coefficient of about 38 Oppm / ° C the core 66 expands with a temperature change ⁇ T. Since the core 66 is constrained by the coil 67 and hardly expands in the radial direction, and the expansion in the length direction is dominant, the inductance L decreases according to the equation (27). .
- the amount of change in the inductance has a negative sign.
- the temperature characteristic of the dielectric constant of L i Nb_ ⁇ 3 since having a positive temperature coefficient the amount of change delta C in capacitance due to temperature change delta T has a positive sign.
- FIG. 60 A sixth 0 FIG coil 6 7 the core 6 6 was the polystyrene, with L i N b 0 3 fin evening one di digital capacitor formed on a substrate, actually a case where the fill evening circuit It is a transmission characteristic measurement result.
- 65a is a pass characteristic measured at a measurement temperature of 25 ° C.
- fr 25 is a resonance frequency of the parallel element.
- FIG. 61 is an enlarged view of the vicinity of the resonance frequency in FIG.
- the fluctuation of the resonance frequency and the fluctuation of the resonance frequency due to the inductance cancel each other out, and the fluctuation of the resonance frequency is about 3.5 MHz. This is smaller than when the inductor is a chip inductor and when the inductor is an air-core coil.
- the fluctuation of the resonance frequency due to the temperature change ⁇ T 50 ° C.
- is about 3.5 MHz, ing. Therefore, in order to make the fluctuation of the resonance frequency zero, it is preferable to use a coil having a material of about 146 ppm / ° C as a core. Also, to allow fluctuations in the resonance frequency of up to 13.5 MHz, it is better to be about 7 ppm / ° C. A larger material may be used as the core.
- the resonance frequency is set to be lower than the anti-resonance frequency of the surface acoustic wave resonator 2 so that the resonance frequency of the series circuit composed of the coil and the capacitor can be confirmed, but is set near the anti-resonance frequency.
- the effect is the same.
- the capacitance change of the digital capacitor due to temperature change ⁇ C The fluctuation of the resonance frequency due to the change in the inductance of the coil using polystyrene as the core cancels out the fluctuation in the resonance frequency, and the fluctuation in the resonance frequency can be made smaller than when using the chip inductor. Irrespective of the change, low loss and wide band pass characteristics and wide attenuation over a wide band can be realized, and electrical performance can be guaranteed regardless of environmental temperature.
- FIG. 62 is a configuration diagram showing a filter circuit according to Embodiment 25 of the present invention.
- the configuration of the filter circuit of FIG. 62 is basically the same as the configuration of the filter circuit of FIG. 9 in the first embodiment, except that the capacitor 15 is formed on a crystal substrate. The difference is that one digital capacitor is used.
- the quartz substrate has a wide temperature range, as shown in Reference 2, pplll ⁇ 113.
- This is a substrate having a so-called zero-temperature characteristic with little characteristic change in the temperature range. Therefore, by forming an in-digital capacitor on a crystal substrate, the capacitance of the in-digital capacitor does not change with temperature and exhibits stable characteristics. Therefore, low-loss, wide band pass characteristics and large attenuation over a wide band can be realized, and electrical performance can be guaranteed irrespective of environmental temperature.
- the filter circuit according to the present invention allows signals in a specific frequency range used in communication equipment and the like to pass, while attenuating signals outside the specific frequency range, Even if the frequency is far from the attenuation band, it is suitable for the one that needs to realize low loss and wide band pass characteristics and to realize large attenuation over wide band.
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP02788838A EP1455448B1 (en) | 2001-12-14 | 2002-12-13 | Filter circuitry |
US10/493,662 US7061345B2 (en) | 2001-12-14 | 2002-12-13 | Filter circuit with series and parallel elements |
DE60229068T DE60229068D1 (de) | 2001-12-14 | 2002-12-13 | Filterschaltung |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2001382022 | 2001-12-14 | ||
JP2001-382022 | 2001-12-14 | ||
JP2002220087A JP2003243966A (ja) | 2001-12-14 | 2002-07-29 | フィルタ回路 |
JP2002-220087 | 2002-07-29 | ||
JP2002-256588 | 2002-09-02 | ||
JP2002256588A JP2004096539A (ja) | 2002-09-02 | 2002-09-02 | フィルタ回路 |
Publications (1)
Publication Number | Publication Date |
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WO2003052930A1 true WO2003052930A1 (fr) | 2003-06-26 |
Family
ID=27347962
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2002/013088 WO2003052930A1 (fr) | 2001-12-14 | 2002-12-13 | Circuit de filtrage |
Country Status (4)
Country | Link |
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US (1) | US7061345B2 (ja) |
EP (1) | EP1455448B1 (ja) |
DE (1) | DE60229068D1 (ja) |
WO (1) | WO2003052930A1 (ja) |
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RU2444839C2 (ru) * | 2010-05-17 | 2012-03-10 | Федеральное государственное унитарное предприятие Омский научно-исследовательский институт приборостроения (ФГУП ОНИИП) | Полосовой пьезоэлектрический фильтр |
CN103023452A (zh) * | 2011-09-21 | 2013-04-03 | 北京北方微电子基地设备工艺研究中心有限责任公司 | 滤波电路和具有其的双频等离子处理装置 |
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2393054A (en) * | 2002-09-12 | 2004-03-17 | Agilent Technologies Inc | Electrical notch filter with acoustic resonators |
US6879224B2 (en) | 2002-09-12 | 2005-04-12 | Agilent Technologies, Inc. | Integrated filter and impedance matching network |
GB2393054B (en) * | 2002-09-12 | 2005-09-28 | Agilent Technologies Inc | Electrical filter |
RU2444839C2 (ru) * | 2010-05-17 | 2012-03-10 | Федеральное государственное унитарное предприятие Омский научно-исследовательский институт приборостроения (ФГУП ОНИИП) | Полосовой пьезоэлектрический фильтр |
CN103023452A (zh) * | 2011-09-21 | 2013-04-03 | 北京北方微电子基地设备工艺研究中心有限责任公司 | 滤波电路和具有其的双频等离子处理装置 |
Also Published As
Publication number | Publication date |
---|---|
DE60229068D1 (de) | 2008-11-06 |
US20040246077A1 (en) | 2004-12-09 |
EP1455448A4 (en) | 2005-04-06 |
US7061345B2 (en) | 2006-06-13 |
EP1455448B1 (en) | 2008-09-24 |
EP1455448A1 (en) | 2004-09-08 |
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