TW578373B - Thin-film bulk acoustic resonator filtering device and duplex using the device - Google Patents

Abstract

The invention provides a filtering device applied in a thin-film bulk acoustic resonator (FBAR) and duplex using the device. The FBAR duplex includes a first port, a second port and a third port; a transmitting side filtering device disposed between the first port and the second port and coupled to the first port and the second port; and a receiving side filtering device disposed between the first port and the third port and coupled to the first port and the third port, wherein each of the transmitting side filtering device and receiving side filtering device comprises at least an FBAR circuit. In addition, the FBAR circuit includes either one of the serial-connected and/or parallel-connected inductor and capacitor to effectively achieve the purpose of adjusting the bandwidth of FBAR circuit, the attenuation of the filtering device in guard band, and impedance matching.

Description

578373 _Case No. 91138134_ Year Month Date__ V. Description of the invention (1) [Technical field to which the invention belongs] A thin film bulk acoustic wave filter device and a duplexer using the device, more specifically, there are The invention relates to a filtering device and a duplexer that pass any one of series and / or parallel inductors and capacitors to the film bulk acoustic wave resonator. [Previous technology] With the rapid development of mobile communication technology, many mobile communication products, such as mobile phones, satellite positioning systems, Bluetooth-specific transmission modules, or other transmission modules through wireless modes, have become indispensable in mobile communication products. Technology development field. At this stage, the developers of wireless communication technology are developing in the direction of excellent communication quality, thinness and shortness. Therefore, how to optimize the performance and volume of the electronic components or mechanical components inside these wireless communication products has become a very important issue. Take the necessary filtering device in wireless communication products as an example. It is a device that uses a combination of resistors, inductors, and capacitors to allow a specific frequency to pass, and cuts or attenuates other frequencies. The chirped wave devices currently used mainly include surface acoustic wave filter devices, ceramic filter devices, quartz chirped wave devices, laminated LC wave devices, dielectric wave devices, and thin-film bulk acoustic wave filter devices. Among them, the thin film bulk acoustic wave filter device is considered to be the most promising type of filter device in the future due to its thin film, small size, high operating frequency, low insertion loss, and easy integration with integrated circuits. It is in line with the future trend of System On a Chip integrated electronic components. However, if the thin-film bulk acoustic resonator is used to design the transmission in a duplexer

578373 _Case No. 91138134_ Year Month Date__ V. Description of the invention (2) When the transmitting end filtering device and the receiving end filtering device are connected, after the transmitting end filtering device and the receiving end filtering device are connected to an antenna end, the transmission The separation between the signal and the received signal is mainly determined by the frequency of the signal itself. Therefore, on the one hand, it is necessary to ensure that the signal sent from the transmitting end can be directly sent to the antenna end; on the other hand, it is necessary to prevent the signal from being fed back to the receiving end, thereby causing damage to the low-noise amplifier unit that runs through the receiving end. Furthermore, the thin film bulk acoustic wave resonator is used to make a filtering device, and according to its circuit structure, it can be divided into two types: a ladder type (Ladder * Type) and a lattice type (Lattice Type). As for the specifications of the duplexer, according to the requirements of different systems, the guard band between the transmitted signal and the received signal is usually less than two percent of the carrier frequency, and the frequency of the transmitted signal and the received signal The width is usually three percent of the carrier frequency. That is, both the transmitting-side filtering device and the receiving-side filtering device require quite steep roll-offs (Rol 1-off). In addition, in order to ensure that the transmitted signal and the received signal do not interfere with each other, the passband attenuation of the two band-pass filtering devices in the other band-pass filtering device must meet the specifications. According to the foregoing, in order that the signal sent from the transmitting end will not be fed back to the receiving end and can be directly sent to the antenna end to send out the signal, a conventional technique is to couple a filter between the antenna end and the receiving end filtering device. A quarter-wavelength transmission line is used to reflect the signal of the transmitting end through a phase shift, thereby preventing the signal of the transmitting end from being fed back to the receiving end. However, the biggest disadvantage of this solution technology is that the added transmission line will greatly increase the overall size of the duplexer. In addition, because of the increase of the transmission line, unnecessary signal interference will occur, that is, the so-called parasitic effect. Another solution technology department

578373 Amendment No. 9Π38134 V. Description of the invention (3) The thin film bulk acoustic wave resonator and a Crystal Filter are very high and are not economical [Content of the Invention] To solve the above-mentioned conventional technology, a thin film bulk acoustic wave resonator is provided for Solve the problem that the thin-film bulk acoustic wave device's attenuation wave signal wave device causes the non-resonance of the wave wave device to be stacked in which the stacked crystals are connected in series. But benefits. Lack of technique Oscillator filter, wave resonator Another object of the present invention is to provide a duplexer that uses and disposes of the device, and reduces the weight. Another object of the present invention is to provide a duplexer for placing and using the device, which is fed back to the receiving end to damage the receiving end. Another object of the present invention is to provide a duplexer for placing and using the device, and the volume of the duplexer increases. In order to achieve the above-mentioned purpose, the device includes a plurality of band-pass filter devices composed of a thin film body. The present device uses the aforementioned ladder filter to install the ladder film bulk acoustic wave resonator filter with the same resonance frequency. That is, all series frequencies; all parallel thin film bulk sounds, the parallel thin film bulk acoustic resonance filter and wave device (Stacked, considering the cost of the process, the main purpose of the present invention is the device and the duplex using the device Limitation of its own bandwidth. A thin-film bulk acoustic wave filter is used to increase the filtering device. A thin-film bulk acoustic wave filter is used to prevent the low-noise amplification unit sent from the transmitting end. A thin-film bulk acoustic wave filter does not require The parasitic effect necessary through the additional transmission line. Invented film bulk acoustic wave acoustic wave element Thin film bulk acoustic resonator filter set architecture. Wave device comprises at least two thin film bulk acoustic wave resonators is a resonator of a resonant frequency. The resonant frequency slightly lower than the sub-sequence

Page 8 578373 _case number 91138134_year month__ V. Description of the invention (4) The resonance frequency of the thin film bulk acoustic wave resonator. In addition, the ladder-type thin-film bulk acoustic wave filter device further comprises at least one element of any one of an inductor and a capacitor connected in series and / or in parallel with the thin-film bulk acoustic wave resonator. Through the structure of any of the series and / or parallel inductors and capacitors in the thin film bulk acoustic wave resonator, different series and / or parallel forms and / or series and / or parallel inductors and capacitors can be passed The amount is adjusted so as to adjust the bandwidth of the thin film bulk acoustic wave filter device. On the other hand, the film bulk acoustic wave duplexer of the present invention includes a first port, a second port, and a third port; an interposition between the first port and the second port and the first port and the second port; A transmitting-end thin-film bulk acoustic wave filter device coupled to the second port; and a receiving-end thin-film bulk acoustic wave filter device connected between the first and third ports and coupled with the first port and the third port Device. The first port is coupled to an antenna terminal for transmitting and receiving signals. In addition, the transmitting-end thin-film bulk acoustic wave filter device and the receiving-end thin-film bulk acoustic wave filter device both include at least one thin-film bulk acoustic wave resonator. In addition, the transmitting-end thin-film bulk acoustic wave filter device and the receiving-end thin-film bulk acoustic wave filter device each include at least one of an inductor and a capacitor connected in series and / or in parallel with the thin-film bulk-acoustic wave resonator. Compared with the conventional thin film bulk acoustic wave filter device and the duplexer using the device, the thin film bulk acoustic wave filter device and the duplexer using the device of the present invention cause duplexing without passing through an additional transmission line. Before the volume of the device is greatly increased, it can solve the limitation of the bandwidth of the thin film bulk acoustic resonator, increase the attenuation of the filter device in the repulsion band, and prevent the signal sent by the transmitting end from feeding back to the receiving end to damage the low level of the receiving end Noise

578373 Amendment No. 91138134 V. Description of the invention (5) Large unit and prevent unnecessary parasitic effects. [Embodiment] A thin film bulk acoustic wave filter device and a duplexer using the device. The thin film bulk acoustic wave filter device 100 of the present invention includes a plurality of thin film bulk acoustic wave resonators, and the operating frequency range of the thin film bulk acoustic wave resonators can be from 400 MHz to 20 GHz. Please refer to Fig. 1. A typical thin film bulk acoustic resonator 1 0 1 is mainly composed of an upper electrode 20 1, a lower electrode 2 02 and a piezoelectric layer 2 0 3. Referring to FIG. 2, when a radio frequency (RF) signal passes through the thin-film bulk acoustic wave resonator 101, resonance occurs through electromechanical conversion of the piezoelectric layer, and its impedance will change drastically near the resonance frequency. At the point where the series resonance frequency (f r) is the smallest virtual impedance, the thin film bulk acoustic wave resonator 101 is a path; while at the parallel resonance frequency (fa), the point is the largest virtual impedance, the thin film bulk acoustic wave resonator 101 is an open circuit. The aforementioned difference in resonance frequency Δί (= ί3-fr) has a great influence on the thin film bulk acoustic wave filter device 100. Before the bearing, the material of the piezoelectric layer must be aluminum nitride, zinc oxide, or zirconium titanate, and the electrode material must be aluminum, gold, platinum, or molybdenum. In this embodiment, the thin film bulk acoustic wave filter device is applied to a duplexer for signal transmission. Due to the large phase speed of aluminum nitride, it is suitable for a high frequency filter device and is used in a duplexer. . Therefore, the piezoelectric layer 230 is made of aluminum nitride, and the upper and lower electrodes 2 01 and 202 are made of aluminum. Please refer to FIG. 3, which shows the structure of the thin film bulk acoustic wave filter device 100 of the present invention. According to the foregoing description, the thin film bulk acoustic wave filter device 100 includes thin film bulk acoustic wave resonators 101, 103, and 105 connected in series.

Page 10 578373 Case No. 9U38134 Month, Amendment V. Description of the Invention (6) Parallel film bulk acoustic wave resonators 107 and 109. Please refer to Fig. 4, which shows the frequency response of the film bulk acoustic resonator 1 0 1. Due to the aforementioned characteristics of the thin-film bulk acoustic wave resonator 101, the frequency of the thin-film bulk acoustic wave filter device 100 has a deep bending point (η 〇) in response to the high-frequency side and the low-frequency side of the passband. tch), which also causes a steep piping. Therefore, the attenuation of the repulsive band of the thin film bulk acoustic wave filter device 100 is not ideal in designing a duplexer, and is limited by the bandwidth of the thin film bulk acoustic wave resonator 1 0 1 itself, that is, The difference Δ f between the series resonance frequency (fr) and the parallel resonance frequency (fa) is determined by the materials used, so the entire filtering device may not meet the requirements of the duplexer design. Therefore, it is necessary to solve the above problems by adding adjustment components such as any one of an inductor and a capacitor. Please also refer to Figs. 5 (A) to 6 (B). The thin film bulk acoustic wave filter device 100 of the present invention is a thin film bulk acoustic wave resonance through at least one inductor connected in series and / or in parallel. This method can increase the bandwidth of the thin-film bulk acoustic resonator. In contrast, the manner in which at least one capacitor in series and / or parallel is connected to the thin film bulk acoustic wave resonator will reduce the frequency bandwidth of the thin film bulk acoustic wave resonator. Since the thin film bulk acoustic wave filter device 100 of the present invention uses aluminum nitride as a piezoelectric material to be used in a duplexer, the frequency bandwidth needs to be increased. Therefore, at least one inductor is selected through a series and / or parallel connection. In the manner of the thin film bulk acoustic wave resonator, the purpose of increasing the thin film bulk acoustic wave resonator bandwidth is achieved. In addition, please refer to FIG. 7 and adjust the generated high-frequency side through the above-mentioned series and / or parallel connection of at least one inductor to the thin-film bulk acoustic resonator.

Page 11 578373 Case No. 91138134 Temple Moon Day _ V. Description of the invention (7) or the downward bending point on the low frequency side, the film bulk acoustic wave resonator wave device 100 can be controlled to repel band attenuation on the high frequency side or the low frequency side Reduction reaches a certain value. On the other hand, please refer to FIG. 8, which shows the structure diagram of the thin film bulk acoustic wave duplexer of the present invention. These include a first port 310, a second port 320, and a third port 330. Among them, a transmitting-end film bulk acoustic wave filter and wave device 120 are interposed between the first port 310 and the second port 320, and are coupled to the first port 310 and the second port 320. The end-film bulk acoustic wave resonator wave device 130 is interposed between the first port 310 and the third port 330, and is coupled to the first port 310 and the third port 330.

The transmitting-end thin-film bulk acoustic wave filter device 120 includes a thin-film bulk acoustic wave resonator 121, 123, 125, 127, 129 and an inductor 113 connected in parallel with the thin-film bulk acoustic wave resonator 125. The receiving end thin film bulk acoustic wave filter device 130 includes a thin film bulk acoustic wave resonator 1 3 1, 1, 3 3, 1 3 5, ^ 7, 139, and an inductor 115 connected in parallel with the thin film bulk acoustic wave resonator 131. And an inductor 117 connected in parallel with the thin film bulk acoustic wave resonator 133.

Since the thin film bulk acoustic wave filter device 100 is used in a duplexer for transmitting and receiving signals in a mobile phone device. Then the thin film bulk acoustic wave filter device 100 needs to be divided into the transmitting thin film bulk acoustic wave filter device 120 and the receiving thin film bulk acoustic wave filter device 130. When designing the thin film bulk acoustic wave filter device at the transmitting end 120, it is only necessary to consider the problems of bandwidth and attenuation. However, in the part of the receiving thin film bulk acoustic wave filter device 130, it is necessary to consider the problem of impedance matching with the transmitting end thin film bulk acoustic wave filter device 120. According to the foregoing, when the bulk acoustic wave filter device through the transmitting end film

Page 12 578373 Case No. 91138134 ___ ί Amendment V. Description of the invention (8) When transmitting the antenna terminal 1 2 0 connected to the first port 1 2 0, it is necessary to consider whether the signal sent by the terminal will be fed back to the The receiving end runs through the low noise amplifying unit (not shown). Therefore, it is necessary to ensure that the receiving-end thin-film bulk acoustic wave filter device 130 is viewed from the transmitting-end thin-film bulk acoustic wave filter device 1 2 0, and the impedance seen in the transmitting-end thin-film bulk-acoustic wave filter device 1 2 0 The passband frequency is high impedance, so the problem of impedance matching must be considered. For this reason, as described above, the thin-film bulk acoustic wave resonator 131 of the receiving-end thin-film bulk acoustic wave filter device 130 closest to the transmitting-end thin-film bulk acoustic-wave resonator filter device 120 is connected in parallel with the inductor 115. Referring to FIG. 9, in the passband band of the transmitting-end thin-film bulk acoustic wave filter device 120, the receiving-end thin-film body seen from the transmitting-side thin-film bulk acoustic wave filter device 120 The acoustic resonator filter device 130 has a high impedance. In other words, signals sent from the transmitting end within this frequency bandwidth are not fed back to the receiving end. It should be noted that the ladder-type structure adopted by the receiving-end thin-film bulk acoustic wave filter device 130 must not be the structure shown in FIG. 10. The reason is that if the ladder-type structure is adopted, when the receiving end thin film bulk acoustic wave filter device 130 is viewed from the receiving end thin film bulk acoustic wave filter device 130, the receiving end thin film bulk acoustic wave device The sub-filtering device 130 must have a low impedance, so the aforementioned problem of impedance matching cannot be solved. However, the thin film bulk acoustic wave filter device 120 at the transmitting end does not need to consider this structure. After determining the position of the first inductor at the film bulk acoustic wave filter device 100, the other external inductors will be different due to the placement position.

Page 13 578373 Case No. 91138134 Date: Amendment 5. Description of the invention (9) It has different influences on the overall impedance. Please refer to FIG. 11. When an inductor 117 is connected in series at the thin film bulk acoustic wave resonator device 13 of the thin film bulk acoustic wave resonator device 130 installed at the receiving end, the thin film bulk acoustic wave filter device near the transmitting end is connected. The vicinity of the high frequency margin of 120 will cause the receiving-end thin-film bulk acoustic wave filter device 130 to generate another resonance point, so that the impedance is present and another peak point is generated. Please refer to Figures 12 (A) to (C). When the thin film bulk acoustic wave filter device 130 at the receiving end is coupled with two external inductors, its structure has three forms to meet the requirements of high impedance. As for more than two external inductors, they can be extended according to the aforementioned principles, and will not be described in detail here. According to the foregoing description, the insertion loss and reflection loss of the thin film bulk acoustic wave duplexer 300 of the present invention have the characteristics shown in Figures 13 (A) to 13 (B), and their dimensions are as follows:

Material Frequency Band Nominal Center Frequency (f0) (MHz) Band 苋 (Bff) (MHz) Passband Loop Loss (dB) Rejection Band Insertion Loss (dB) Aluminum Aluminum Nitride Aluminum Rx (2 |) 1960 /. ± 30 13 min. 55 min. * Tx (2 {) 1880 il nun. 45 min. Thickness of bottom electrode of material band (#m) Thickness of piezoelectric it (Mm) * Area ("2) Auxiliary sensor (ΗΗ) Aluminum Aluminum Nitride Aluminum Rx (2;) 0.3 1.8 Parallel: G.525 Series: 0.475 200x200, 143x143 267x267, 152x152, 277x277, 137x137 ^ 210x210 2.44, 4. 87 Tx (2 {) Parallel: Q.595 Tandem: 0.552 610x610 610x610 123x123, 477x477, 477x477. 82x82 10.66 p.14 578373 _ case number 91138134_ year month day__ V. Description of the invention (10) Please refer to Figures 14 (A) and (B), which shows this Other implementation architectures of the invented duplexer. It should be noted that the architecture disclosed in this embodiment is not the only embodiment. The above is only the thin film bulk acoustic wave filter device of the present invention and the device using the device. The preferred embodiment of the duplexer is not intended to limit the scope of the essential technical content of the present invention. The essential technical content of the thin film bulk acoustic wave filter device of the present invention and the duplexer using the device is broadly defined below In the scope of the patent application mentioned above, any technical implementation completed by others Method or, if the patent as defined by the scope of the following identical or equivalent to the changes, this will be regarded as encompassed within the scope of the patent.

Page 15 578373 Amendment No. 91138134 Brief description of the drawings [Simplified description of the drawings] Figure 1 is a schematic diagram of the structure, which shows the main structure of a typical thin-film bulk acoustic wave resonator; Figure 2 is a relationship diagram. To show the relationship between the frequency and impedance of the thin-film bulk acoustic wave resonator; FIG. 3 is a schematic diagram showing the structure of the thin-film bulk acoustic wave filter device of the present invention; and FIG. 4 is a frequency response diagram showing Frequency response of the thin-film bulk acoustic wave filter device; Figures 5 (A) and 5 (B) are a relationship diagram for showing the thin-film bulk acoustic wave filter device of the present invention, which is connected in series and / or in parallel through a When the inductor is in the thin film bulk acoustic wave resonator, the impedance change of the thin film bulk acoustic wave resonator; Figures 6 (A) and 6 (B) are a relationship diagram for showing the thin film bulk acoustic wave filter device of the present invention , When a capacitor is connected in series and / or in parallel with the thin film bulk acoustic wave resonator, the impedance change of the thin film bulk acoustic wave resonator is shown in FIG. 7 is a schematic diagram showing the thin film bulk sound of the present invention The relationship between the frequency response of the resonator filter device applied to the duplexer; Figure 8 is a schematic diagram of the structure, used to show the structure of the film bulk acoustic wave resonator duplexer of the present invention; Figure 9 is a relationship diagram, The frequency and impedance of the thin-film bulk acoustic wave resonator closest to the transmitting-end thin film bulk acoustic wave filter device in parallel with an inductor are shown in the thin-film bulk acoustic wave filter device at the receiving end.

Page 16 578373 Case No. 91138134 Revised diagram to briefly explain the relationship between the impedances; Fig. 10 is a thin-film body at the receiving end in an architecture indicator; Fig. 11 is a diagram of a bulk acoustic wave resonator wavelet device; In the case of the first inductor, the frequency and impedance of the first duplex inductor in the duplexer of Figures 12 (A) to 12 (C) are in accordance with the high impedance of the three types of 13 (A) and 13 (B). The relationship between the bulk acoustic wave resonator duplexer; and the thin-film bulk acoustic wave resonator double-intent 'sound wave common in Figures 14 (A) and 14 (B), which is used to set up a parallel relationship. A bulk acoustic wave may be built. The first embodiment is used to display the non-vibrator filter installed on the receiving end of the thin film bulk acoustic wave system; a schematic diagram, a resonator filter structure; a diagram, the insertion loss is suitable for the double-type ladder of the present invention The receiving end of the device is connected in series with a thin-film bulk acoustic resonance resonator to display the device of the present invention, and two electrical displays of the thin and reflective loss of the present invention. A schematic diagram of the structure is used to show the difference of the working device of the present invention. Implementation architecture. 100 Thin film bulk acoustic wave filter device 101, 103, 105, 107, 109 Thin film bulk acoustic wave filter 111, 113, 115, 117 Inductor 120 Thin film bulk acoustic wave filter device 121, 123, 125, 127, 129 Bulk acoustic wave resonator 130 Thin film bulk acoustic wave filter device at the receiving end 131, 133, 135, 137, 139 Thin film bulk acoustic wave resonator 140 Antenna end 201 Upper electrode

Page 17 578373

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Claims (1)

578373 _Case No. 91138134 Rev. V on June 6th_Applicable patent scope 1. A filter device for a thin-film bulk acoustic wave resonator, the device includes a plurality of elements connected in series; a plurality of elements connected in parallel; and at least one Any one of inductance and capacitance, wherein the series element and the parallel element are coupled into a ladder-type circuit, and the series element and the parallel element each include a thin film bulk acoustic resonator, the at least An inductor and a capacitor are coupled with the thin film bulk acoustic wave resonator of the filtering device in parallel or in series. 2. A filter device for a thin-film bulk acoustic wave resonator, the device comprising: a plurality of elements in series; a plurality of elements in parallel; and at least one of an inductor and a capacitor, wherein the series elements and the parallel elements Is a circuit coupled to a ladder structure, and the series element and the parallel element both include a thin film bulk acoustic resonator, and any one of the at least one inductor and capacitor is connected to the thin film bulk acoustic resonator of the filtering device Coupling in either parallel or series. Each thin film bulk acoustic resonator has a resonance frequency. The thin film bulk acoustic resonators included in the series elements have the same resonance frequency. The thin films included in the parallel components The bulk acoustic wave resonator also has the same resonance frequency, and the resonance frequency is slightly lower than the resonance frequency of the thin film bulk acoustic wave resonator included in the series-connected element. 3. A filtering device for a thin-film bulk acoustic wave resonator, the device comprising: Page 578 373 Page 20 578373 Case No. 91138134 _η Amendment 6. The scope of application for patents is connected. 9. For patent application, self-signal input. 10. If the scope of patent application is applied, the inductor is used to reduce the amount and different filters are used to adjust any of the filters. 11. A thin-film bulk acoustic wave, a first port connected to the second wave, a wave interposed between the first connection, a third circuit coupled to the acoustic wave resonance circuit, and a parallel one. 1 2. If you apply for a dedicated antenna end receiver. 1 3. If the application specifically includes any one of the scopes of benefits • Wall One > Le — Item 7 in which the electrical end of the ladder structure is viewed as having no parallel film bulk acoustic wave resonance item 1 or item 1 The device of item 2 or item 3, wherein the impedance matching between the passband frequency of the filtering device and the attenuation of the repulsion band is matched, and the attenuation of the passband of the capacitive wave device and the repulsion band are the same. A duplexer of a resonator, the device includes: a second port and a third port; a port between the second port and the first and the second device; and a port between the third port and the first port A port and the wave device, the wave device includes at least a ladder-shaped thin film body, and at least one of the thin film bulk acoustic wave resonator of the filter device and the thin film bulk acoustic wave resonator is coupled in series with any of an inductance and a capacitor. A duplexer according to item 11, wherein the first port is a signal transmission terminal; a third port is a duplexer according to signal range 11; wherein the filtering device Page 21 578373 _Case No. 91138134_ YYYY__ VI. The scope of patent application includes: a plurality of elements connected in series; a plurality of elements connected in parallel; and at least one of an inductor and a capacitor, wherein the Xinlian The element and the parallel element are coupled into a ladder-type circuit, and the serial element and the parallel element both include a thin film bulk acoustic resonator, and any one of the at least one inductor and capacitor is connected to the filtering device. The thin-film bulk acoustic wave resonators are coupled in either parallel or series. 14. The duplexer according to item 11 of the scope of patent application, wherein the filtering device comprises: a plurality of elements in series; a plurality of elements in parallel; and at least one inductor, wherein the series elements and the parallel elements The components are coupled into a ladder-type circuit, and the series components and the parallel components both include a thin film bulk acoustic resonator, and any one of the at least one inductor and capacitor is in resonance with the thin film bulk acoustic wave of the filtering device. The sons are coupled in either parallel or series. Each thin film bulk acoustic wave resonator has a resonance frequency. The thin film bulk acoustic wave resonators included in the conjoined elements have the same resonance frequency. The thin film bulk acoustic wave resonator also has the same resonance frequency, and the resonance frequency is slightly lower than the resonance frequency of the thin film bulk acoustic wave resonator included in the series-connected element. Page 22 578373 __Case No. 91138134_ Year and Month Amendment_ VI. Patent Application Range 15. For example, the duplexer of the 11th scope of the patent application, wherein the filtering device includes: a plurality of elements connected in series; a plurality of A parallel element; and at least one of an inductor and a capacitor, wherein the connected element and the parallel element are connected in a ladder-type circuit, and the serial element and the parallel element include A thin-film bulk acoustic wave resonator, any one of the at least one inductor and a capacitor is coupled to the thin-film bulk acoustic wave resonator of the filtering device in parallel or in series, and all the thin-film bulk acoustic wave resonances in the filtering device The sub is used to generate at least two different resonance frequencies. 16. The duplexer according to item 15 of the scope of patent application, wherein each thin film bulk acoustic wave resonator in the filtering device has a different resonance frequency. 17. The duplexer according to item 11 of the scope of patent application, wherein the filtering device interposed between the first port and the second port and coupled with the first and second ports is a signal transmitting device. Filtering device. 18. For example, the duplexer of claim 17 in which one of the at least one inductor is connected in parallel with a thin film bulk acoustic resonator closest to the signal output terminal, and any of the remaining inductors and capacitors is in parallel. It is used to couple other thin film bulk acoustic resonators in series or parallel. 19. For example, the duplexer of the scope of application for patent No. 11 wherein the filtering device interposed between the first port and the third port and coupled with the first port and the third port is a receiver Signal filtering device. Page 23 578373 _Case No. 91138134_Year_Month__ VI. Application scope of patent 2 0. For example, the duplexer of the scope of patent application No. 19, wherein one of the at least one inductor is an inductor and a signal The thin film bulk acoustic resonator closest to the input is connected in parallel, and any of the remaining inductors and capacitors is used to connect the other thin film bulk acoustic resonators in series or in parallel. 2 1 · If the duplexer of item 19 in the scope of patent application, the ladder-type circuit, from the signal input end, can not have a thin film bulk acoustic resonator in parallel. 2 2 · If the duplexer of item 11 in the scope of patent application, wherein the inductance is used to adjust any one of the filter device's passband bandwidth, repel band attenuation, and impedance matching between different filter devices, The capacitor is used to adjust any one of the bandwidth of the passband and the attenuation of the repulsion band of the filtering device. 2 3. The duplexer according to item 11 of the patent application scope, wherein the duplexer is used in a wireless communication device.