JP2006005798A - Band-pass filter and method of setting filter characteristic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a band-pass filter while allowing it to have desired characteristics. <P>SOLUTION: A ground conductor layer is formed on one surface of a laminate substrate on which a plurality of dielectric layers and conductor layers are laminated, and resonant pattern conductor layers each having resonant electrode patterns 161a, 161b each of which one end is a short circuit end connected to the conductor layer and the other end is an open end are formed via the dielectric layer so as to oppose the conductor layer. The open end side of the resonant electrode is connected to input and output terminals TPa and TPb, and signals of desired frequency bands among signals inputted into one input and output terminal TPa are allowed to pass and outputted from the other input and output terminal TPb. A plurality of characteristic correcting patterns 182 projected like stubs or T shapes from the ground pattern 181 connected to the ground conductor layer are formed on the resonant electrode patterns 161a, 161b via the dielectric layer, and the pattern 182 is selectively separated from the ground pattern 181 so that the filter may have the desired characteristics. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a band pass filter and a filter characteristic setting method. Specifically, in a band-pass filter formed using a resonance electrode, a characteristic correction pattern that protrudes in a stub shape or T-shape from a ground pattern connected to the ground conductor layer is placed on the resonance electrode via a dielectric layer. A plurality of characteristic correction patterns are selectively separated from the ground pattern, whereby the filter characteristics are brought close to desired filter characteristics.

  With the spread of telephone systems such as mobile phones and wireless LAN (local area network) systems, such as communication systems that use microwave and millimeter wave high frequency radio waves as carriers, it is easy to use in various places such as home and outdoors. In addition, various data can be transmitted and received without using a relay device or the like.

  Such devices used in the communication system are provided with filter elements such as a low-pass filter (LPF), a high-pass filter (HPF), and a band-pass filter (BPF). This filter element is designed not as a lumped constant circuit but as a distributed constant circuit in order to process a signal in a high frequency band. For example, as shown in Patent Document 1, a triplate structure filter is formed using a pair of parallel conductor patterns.

  In addition, miniaturization by high-density mounting, multilayering of substrates, and the like has been achieved so that devices can be easily carried. For example, as shown in Patent Document 2, when a pattern wiring layer, a dielectric insulating layer, or the like is multilayered, a layer in which a filter, a capacitor, an inductor, a resistor, or the like is formed, a pattern layer for signal wiring, power supply, or the like is provided. A high-frequency module device is made by multilayering.

JP 2000-252716 A JP 2002-334806 A

  By the way, when a band pass filter is formed by electromagnetically coupling a pair of parallel conductor patterns, an electromagnetic field analysis is performed in advance to design a band pass filter so as to obtain a desired filter characteristic. However, due to miniaturization of the bandpass filter, the accuracy of electromagnetic field analysis becomes insufficient when the conductor pattern is miniaturized, and the desired filter characteristics can be obtained even if the bandpass filter is designed based on the analysis result. There are cases where it cannot be done. In addition, if the variation in filter characteristics is large, it may be difficult to easily generate a bandpass filter having desired filter characteristics. In such a case, the band pass filter must be reset, and TAT (Turn Around Time) becomes long. In addition, when a matching circuit is added so that the filter characteristic becomes a desired characteristic, the circuit scale becomes large and it is difficult to reduce the size of the bandpass filter. Furthermore, since loss occurs in the matching circuit, a bandpass filter with low loss cannot be obtained.

  Accordingly, the present invention provides a band-pass filter and a filter characteristic setting method that can be reduced in size with desired filter characteristics.

  In the bandpass filter according to the present invention, a ground conductor layer is formed on one surface side of a multilayer substrate formed by laminating a plurality of dielectric layers and conductor layers, and one end is a short-circuit end connected to the ground conductor layer. A resonance pattern conductor layer having a resonance electrode with the other end being an open end is provided to face the ground conductor layer through the dielectric layer, and the open end side of the resonance electrode is connected to the input / output terminal. In a band-pass filter that passes a signal in a desired frequency band from a signal input to the input / output terminal and outputs the signal from the other input / output terminal, it protrudes in a stub shape or T-shape from the ground pattern connected to the ground conductor layer One or a plurality of the above-described characteristic correction patterns are provided on the resonance electrode via a dielectric layer.

  Further, the filter characteristic setting method is such that a ground conductor layer is formed on one surface side of a multilayer substrate formed by laminating a plurality of dielectric layers and conductor layers, and one end is a short-circuit end connected to the ground conductor layer. A resonant pattern conductor layer having a resonant electrode with an open end is provided to face the ground conductor layer with a dielectric layer in between, and the open end side of the resonant electrode is connected to an input / output terminal, and one input In a bandpass filter that passes a signal in a desired frequency band from a signal input to an output terminal and outputs the signal from the other input / output terminal, the signal is projected in a stub shape or a T shape from a ground pattern connected to the ground conductor layer. A plurality of characteristic correction patterns are provided on the resonance electrode via a dielectric layer, and the characteristic correction patterns are selectively separated from the ground pattern so as to obtain desired filter characteristics.

  In the present invention, one terminal of a capacitor is connected to the open end of the resonance electrode, and the other terminal of the capacitor is grounded. Based on the line length of the capacitor and the resonance electrode, the center frequency of the pass band in the filter characteristics is set. A capacitor is provided between the open end of the resonance electrode and the input / output terminal connected to the open end, and the notch frequency of the stop band in the filter characteristics is adjusted by adjusting the capacitance of the capacitor. . The resonant electrode is formed in a meander shape or a spiral shape, and an inductor is provided between the input and output terminals connected to the open end of the resonant electrode, and the inductance of this inductor is varied to adjust the pass band in the filter characteristics. Is done. In addition, one or a plurality of characteristic correction patterns protruding in a stub shape or a T shape from a ground pattern connected to the ground conductor layer are provided on the resonance electrode via a dielectric layer. In addition, the characteristic correction patterns are protruded through respective switches. The characteristic correction pattern is selectively separated from the ground pattern by controlling this switch or by cutting the characteristic correction pattern.

  According to the present invention, a plurality of characteristic correction patterns protruding in a stub shape or T-shape from a ground pattern connected to the ground conductor layer are provided on the resonance electrode via the dielectric layer, and desired filter characteristics are obtained. Thus, the characteristic correction pattern is selectively separated from the ground pattern. Since the characteristic correction pattern can be selectively separated from the ground pattern and the filter characteristic can be corrected in this way, there is no need to reset the band pass filter or add a matching circuit, and a band pass filter with a short TAT and a reduced size can be obtained. Can be easily provided. In addition, it is possible to reduce the occurrence of defective products in which desired filter characteristics cannot be obtained.

  Each of the plurality of characteristic correction patterns protrudes with a switch interposed therebetween, and the characteristic correction pattern is separated from the ground pattern by controlling the switch. For this reason, it is possible to easily correct the filter characteristics, and it is possible to correct the filter characteristics even after the band-pass filter is incorporated.

  Further, one terminal of the capacitor is connected to the open end of the resonance electrode, and the other terminal of the capacitor is grounded, and the center frequency of the pass band in the filter characteristics is set. Thus, by connecting the capacitor between the open end of the resonance electrode and the ground, a desired filter characteristic can be obtained even if the length of the resonance electrode is shorter than a quarter wavelength of the center frequency of the pass band. Even if the capacitance of the capacitors varies, the characteristic correction pattern can be selectively separated from the ground pattern, and the filter characteristic can be corrected to obtain the desired filter characteristic, thereby obtaining the desired filter characteristic. It is possible to reduce the occurrence of defective products.

  In addition, a capacitor is provided between the open end of the resonant electrode and the input / output terminal connected to the open end, and the notch frequency of the stop band in the filter characteristics is adjusted by adjusting the capacitance of the capacitor. The For this reason, the amount of attenuation in the stop band can be increased.

  Further, the resonance electrode is formed in a meander shape or a spiral shape, and an inductor is provided between the input and output terminals. The inductance of the inductor is varied to adjust the pass band in the filter characteristics. For this reason, the band pass filter can be further reduced in size, and desired filter characteristics can be obtained. In addition, even if there is an inductance variation, the characteristic correction pattern can be selectively separated from the ground pattern, the filter characteristic can be corrected to achieve the desired filter characteristic, and the desired filter characteristic cannot be obtained. Can also be reduced.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an equivalent circuit of the bandpass filter 10. One end of the resonance electrode PRa of the band pass filter 10 is grounded, and the other end is connected to the input / output terminal TPa via the capacitor 32a. A capacitor 31a is connected in parallel to the resonance electrode PRa. One end of the resonance electrode PRb of the band pass filter 10 is grounded, and the other end is connected to the input / output terminal TPb via the capacitor 32b. A capacitor 31b is connected in parallel to the resonance electrode PRb. The resonance electrode PRa and the resonance electrode PRb are configured by a microstrip or a stripline, and are arranged in parallel so as to generate electromagnetic field coupling.

  When the signal RFin is input from the input / output terminal TPa of the band pass filter 10, the signal RFin is subjected to filter processing, and the filtered signal RFout is output from the input / output terminal TPb. Here, the center frequency of the pass band in the filter characteristics is set based on the longitudinal length RL of the resonance electrodes PRa and PRb and the capacitance C1 of the capacitors 31a and 31b. Further, by adjusting the capacitance C2 of the capacitors 32a and 32b, the notch frequency of the stop band can be adjusted to increase the attenuation in the stop band. For example, when the capacitances C1 and C2 are increased, the resonance frequency and the notch frequency of the resonator configured using the resonance electrodes PRa and PRb move to the low frequency side. It can be moved to the frequency side. Further, when the capacitances C1 and C2 are reduced, the resonance frequency and the notch frequency move to the high frequency side, and therefore the pass band of the band pass filter 10 can be moved to the high frequency side. Further, by setting the notch frequency of the stop band to a frequency slightly higher or lower than the pass band, the amount of attenuation at a frequency higher or lower than the pass band can be increased, and the filter characteristics can be sharpened.

  Further, if the resonance electrodes PRa and PRb are formed in a meander shape, the length RL of the resonance electrodes PRa and PRb can be increased without increasing the size of the bandpass filter 10, so that signals in a low frequency band are allowed to pass. Is possible. However, when the resonance electrodes PRa and PRb are in a meander shape, the electromagnetic field coupling is weaker and the Q value of the resonator is lower than in the case where the resonance electrodes PRa and PRb are formed in a linear shape. For this reason, by providing the inductor 33 between the input / output terminal TPa and the input / output terminal TPb, the influence of a decrease in the Q value due to the meander shape of the resonance electrodes PRa and PRb is reduced. Further, the pass band can be adjusted by adjusting the inductance L1 of the inductor 33. For example, the bandwidth and the like can be adjusted as in the embodiments described later.

  In the band-pass filter 10 configured as described above, the resonance electrodes, the capacitors 31a and 31b, and the like are formed using a semiconductor process for miniaturization. Further, since the TAT becomes long because a semiconductor process is used, it is easy to set the filter characteristics without using the chip parts as the capacitors 32a and 32b and the inductor 33, and replacing the chip parts without increasing the bandpass filter 10. It can be done promptly.

  By the way, when the filter characteristics are set by changing the chip parts, the filter characteristics may not be set to the desired filter characteristics only by changing the chip parts. Also, the filter characteristics change due to variations in characteristics of capacitors and chip parts formed using a semiconductor process. For this reason, when it is not possible to obtain a desired filter characteristic simply by replacing a chip component with a characteristic correction pattern that changes the filter characteristic, the filter characteristic is changed to the desired filter characteristic by using this characteristic correction pattern. Move closer to.

  2 is a plan view showing the configuration of the band-pass filter 10 using a microstrip, FIG. 3 is a schematic cross-sectional view at the position AA ′ of the band-pass filter 10 shown in FIG. 2, and FIG. An exploded perspective view is shown. A first conductor layer 11 as a ground conductor layer is formed on the back surface side of the first dielectric layer (insulating layer) 12, and a second conductor layer 13 is formed on the front surface side. Further, the first dielectric layer 12 is provided with a conductor layer connecting portion (hereinafter simply referred to as “via”) 121 such as a via hole or a through hole, and the first conductor layer is formed by the via 121. 11 and the second conductor layer 13 are electrically connected.

  A third dielectric layer 15 is formed on the second conductor layer 13 to form a flattened surface used as a buildup formation surface. The third dielectric layer 15 is a resonance pattern conductor layer. A third conductor layer 16 is formed. The third dielectric layer 15 is provided with a via 151, and the second conductor layer 13 and the third conductor layer 16 are electrically connected by the via 151.

  The third conductor layer 16 includes a resonance electrode pattern 161a that becomes the resonance electrode PRa, a resonance electrode pattern 161b that becomes the resonance electrode PRb, and a ground pattern 162. Capacitors 31 a and 31 b are formed on the ground pattern 162 of the third conductor layer 16. The resonance electrode pattern 161a and the resonance electrode pattern 161b have a meander shape, and are arranged side by side so as to be parallel and line-symmetric with a predetermined interval so as to generate electromagnetic field coupling. Further, one end of each of the resonant electrode patterns 161a and 161b is connected to the ground pattern 162, and the other is an open end.

  On the third conductor layer 16 on which the capacitors 31a and 31b are formed, the fourth conductor layer 18 is formed via the fourth dielectric layer 17. The fourth conductor layer 18 connects the ground pattern 181, one or more characteristic correction patterns 182 protruding in a stub shape from the ground pattern 181 in the direction in which the resonant electrode patterns 161 a and 161 b are arranged, the resonant electrode PRa and the capacitors 31 a and 32 a. Connection pattern 183a, resonance electrode PRb and connection pattern 183b connecting capacitors 31b and 32b, connection pattern 184a connecting capacitor 32a and inductor 33 and input / output terminal TPa, capacitor 32b connecting inductor 33 and input / output terminal TPb. The connection pattern 184b and probe ground patterns 185a to 185e for connecting probes used for measuring the filter characteristics are configured.

  The open end of the resonance electrode pattern 161 a in the third conductor layer 16 is connected to the connection pattern 183 a of the fourth conductor layer 18 by a via 172 a provided in the fourth dielectric layer 17. Similarly, the open end of the resonance electrode pattern 161b is connected to the connection pattern 183b by a via 172b. Further, the wiring film 311 s provided on the fourth dielectric layer 17 side of the capacitor 31 a formed on the third conductor layer is connected to the fourth conductor layer 18 by the via 173 a provided on the fourth dielectric layer 17. The connection pattern 183a is connected. Similarly, the wiring film 311s of the capacitor 31b is connected to the connection pattern 183b by the via 173b.

  Furthermore, the ground pattern 162 of the third conductor layer 16, the ground pattern 181 of the fourth conductor layer 18, and the probe ground patterns 185 a to 185 e are connected by the vias 171 of the fourth dielectric layer 17.

  The conductor layer located between the first conductor layer 11 and the third conductor layer 16 on which the resonance electrode patterns 161a and 161b are formed, that is, the second conductor layer 13, includes the resonance electrode patterns 161a and 161b and capacitors. Slots are set so as to include regions 31a, 31b and connection patterns 183a, 183b, 184a, 184b, and the second dielectric layer 14 is provided in these slots. Thus, by providing the slot, no other conductor layer is provided between the resonance electrode patterns 161a and 161b and the first conductor layer 11, and therefore the electromagnetic field of the pair of parallel resonance electrode patterns 161a and 161b. The coupling state is not changed by other conductor layers.

  A capacitor 32a is placed on the connection pattern 183a and the connection pattern 184a of the fourth conductor layer 18, one terminal of the capacitor 32a is connected to the connection pattern 183a, and the other terminal is connected to the connection pattern 184a. Similarly, the capacitor 32b is placed on the connection pattern 183b and the connection pattern 184b, one terminal of the capacitor 32b is connected to the connection pattern 183b, and the other terminal is connected to the connection pattern 184b. Further, the inductor 33 is placed on the connection pattern 184a and the connection pattern 184b, one terminal of the inductor 33 is connected to the connection pattern 184a, and the other terminal is connected to the connection pattern 184b.

  Next, the generation procedure of the band pass filter 10 will be described. The band pass filter 10 uses a so-called printed wiring board as a base substrate. For example, a printed wiring board in which a conductor layer is provided on both surfaces of a dielectric (insulating) substrate is used as the base substrate.

  One conductor layer of the base substrate is a first conductor layer 11, and the other conductor layer is a second conductor layer 13. The first conductor layer 11 and the second conductor layer 13 are electrically connected by, for example, a via 121 provided in the first dielectric layer 12. In the via 121, a hole penetrating the first dielectric layer 12 is formed in a part of the first dielectric layer 12 by drilling, laser processing, plasma etching processing, or the like. A conductive film made of copper can be formed in the hole thus formed by via plating, for example, electrolytic plating using a copper sulfate solution.

  The first dielectric layer 12 is preferably formed of a material with low dielectric loss (low tan δ), that is, a material excellent in high frequency characteristics. Examples of such materials include polyphenylethylene (PPE), bismaleidotriazine (BT-resin), polytetrafluoroethylene, polyimide, liquid crystal polymer (LCP), polynorbornene (PNB), and other organic materials, ceramics, or Examples thereof include a mixed material of ceramic and organic material. The first dielectric layer 12 is preferably formed of a material having heat resistance and chemical resistance in addition to the above-described materials, and an inexpensive epoxy substrate is used as a dielectric substrate made of such a material. FR-5 etc. can be mentioned. In this way, by using an inexpensive organic material as the first dielectric layer 12, the cost can be reduced compared to the case where a relatively expensive Si substrate or glass substrate is used. ing.

  Slots are formed in the second conductor layer 13. For example, the conductor in the slot portion is removed using an etching method. On the second conductor layer 13 in which the slot is formed, an insulating film using an insulating material having a high dielectric constant, for example, an epoxy resin is formed. After the insulating film is formed, the insulating film formed on the second conductor layer 13 is polished until the second conductor layer 13 is exposed. Thereby, the second dielectric layer 14 can be formed in the slot region, and the step between the second conductor layer 13 and the second dielectric layer 14 is eliminated. A third dielectric layer 15 is formed on the second conductor layer 13 and the second dielectric layer 14 to form a planarized surface used as a buildup formation surface.

  On the third dielectric layer 15, the third conductor layer 16 and the capacitors 31a and 31b are formed by a thin film formation technique or a thick film formation technique used in a semiconductor process. The third dielectric layer 15 is preferably formed of a material having a low dielectric loss (low tan δ), that is, an organic material having excellent high frequency characteristics, and is formed of an organic material having heat resistance and chemical resistance. It is preferable. Examples of such an organic material include benzocyclbutene (BCB), polyimide, polynorbornene (PNB), liquid crystal polymer (LCP), epoxy resin, and acrylic resin. The third dielectric layer 15 is made of such an organic material by using a method excellent in coating uniformity and film thickness control, such as a spin coat method, a curtain coat method, a roll coat method, or a dip coat method. It can be formed with high accuracy on the build-up forming surface.

  Next, a conductive film made of, for example, nickel or copper is formed on the third dielectric layer 15 over the entire surface. Thereafter, a pattern of the third conductor layer 16 is formed by using a photolithography technique or the like. That is, the conductive electrode is etched using a photoresist patterned in a predetermined shape as a mask, thereby forming the resonance electrode patterns 161a and 161b and the ground pattern 162. The resonant electrode patterns 161a and 161b and the ground pattern 162 are formed by forming and etching a conductive film made of copper of about several μm, for example, by electrolytic plating using a copper sulfate solution. Further, vias 151 are provided in the third dielectric layer 15, and the ground pattern 162 of the third conductor layer 16 is connected to the second conductor layer 13.

As the capacitors 31a and 31b, for example, tantalum oxide capacitors using tantalum oxide (Ta ₂ O ₅ ) as a dielectric are used. In the tantalum oxide capacitor, a tantalum nitride (TaN) film is formed on a ground pattern 162 serving as one electrode. The tantalum nitride film can be formed by CVD (Chemical Vapor Deposition), sputtering or vapor deposition. The surface layer portion of the tantalum nitride film is anodized to form a tantalum oxide (Ta ₂ O ₅ ) film, which is a high dielectric constant and low loss high dielectric material. Further, a wiring film 311s to be the other electrode of the tantalum oxide capacitor is formed on the tantalum oxide film.

  On the third conductor layer 16 on which the capacitors 31a and 31b are formed, the fourth dielectric layer 17 made of the organic material described above is formed. Next, after a conductive film made of, for example, nickel or copper is formed over the entire surface, the ground pattern 181, the characteristic correction pattern 182, and the connection pattern 183 a of the fourth conductor layer 18 are used using the photolithography technique as described above. , 183b, 184a, 184b and probe ground patterns 185a to 185e. The fourth dielectric layer 17 is provided with vias 171, 172 a, 172 b, 173 a, and 173 b to connect the pattern of the fourth conductor layer 18 with the pattern of the third conductor layer 16.

  Thus, when the characteristic correction pattern 182 is formed on the resonance electrode patterns 161a and 161b, a capacitor is constituted by the resonance electrode patterns 161a and 161b and the characteristic correction pattern 182. The equivalent circuit at this time is shown in FIG. It becomes.

  Next, chip components are used as the capacitors 32a and 32b and the inductor 33 so that the band pass filter can be miniaturized and a desired filter characteristic can be easily obtained. I do. Furthermore, the filter characteristic is changed by selectively separating the characteristic correction pattern 182 from the ground pattern 181 to bring the filter characteristic closer to the desired filter characteristic.

  Next, a method for setting filter characteristics will be described. By setting the filter characteristics before dividing the aggregate substrate 5 on which a plurality of bandpass filters 10 are formed, the filter characteristics can be set efficiently. In setting the filter characteristics, the probe 70 is connected to the probe pad as shown in FIG. 6 using the connection pattern formed on the fourth conductor layer 18 of the bandpass filter 10 and the probe ground pattern as a probe pad. Thereafter, the input of the signal supplied from the signal generator and the output of the filtered signal to the measuring device are performed via the probe 70 to measure the filter characteristics. Based on the measurement result of the filter characteristics, the replacement of the chip parts and the selective separation of the characteristic correction pattern 182 are performed.

  FIG. 7 shows the procedure of the filter characteristic setting method. As shown in FIG. 7A, the substrate connection pattern 183a and the probe ground pattern 185a on which the resonant electrode patterns 161a and 161b, the capacitors 31a and 31b, the characteristic correction pattern 182 and the like are formed are used as probe pads. 71a (the footprint at the tip is SG) is connected. In addition, the probe 71b (the tip footprint is SG) is connected using the ground pattern 183b and the probe ground pattern 185b as a probe pad. One of the two probes 71a and 71b is connected to a signal generator and the other is connected to a measuring instrument to measure the filter characteristics. The equivalent circuit at this time is shown in FIG. 7B because the capacitors 32a and 32b and the inductor 33 are not connected.

  Based on the measurement result of the filter characteristic, the center frequency of the pass band in the band pass filter 10 is set. For example, as shown in FIG. 7C, the center frequency in the band pass filter 10 is set by separating the characteristic correction pattern 182 located on the ground side of the resonance electrode patterns 161a and 161b from the ground pattern 181. The characteristic correction pattern 182 is separated using a laser, a cutter, or the like.

  Next, as shown in FIG. 7D, after the capacitors 32a and 32b are placed, the probe ground pattern 185c, the connection pattern 184a, and the probe ground pattern 185d are used as probe pads to connect the probe 72a (the footprint at the tip is GSG). . Further, the probe ground pattern 185c, the connection pattern 184b, and the probe ground pattern 185e are used as probe pads to connect the probe 72b (the footprint at the tip is GSG). One of the two probes 72a and 72b is connected to a signal generator and the other is connected to a measuring instrument to measure the filter characteristics. Based on the measurement result, the capacitors 32a and 32b are replaced so that the notch frequency of the stop band in the band pass filter 10 is optimized. The equivalent circuit at this time is shown in FIG. 7E because the capacitors 32a and 32b are connected and one characteristic correction pattern 182 is separated from the ground pattern 181 as shown in FIG. 7C.

  Further, after the replacement of the capacitors 32a and 32b is completed, the notch frequency is made closer to the optimum frequency using the characteristic correction pattern 182 based on the measurement result of the filter characteristic. For example, as shown in FIG. 7F, the characteristic correction pattern 182 located second from the ground side of the resonance electrode patterns 161a and 161b is selectively separated from the ground pattern 181 to bring the notch frequency closer to the optimum frequency.

  Next, as shown in FIG. 7G, after placing the inductor 33, the probe 73a (with the footprint at the tip is SG) is connected using the connection pattern 184a and the probe ground pattern 185d as a probe pad. Further, the probe 73b (the tip footprint is SG) is connected using the connection pattern 184b and the probe ground pattern 185e as a probe pad. One of the two probes 73a and 73b is connected to a signal generator and the other is connected to a measuring instrument, and the filter characteristics are measured. Based on the measurement result, the inductor 33 is replaced so that the center frequency and bandwidth of the pass band in the band pass filter 10 are optimized. The equivalent circuit at this time is shown in FIG. 7H because the inductor 33 is connected and the two characteristic correction patterns 182 are separated from the ground pattern 181 as shown in FIG. 7F.

  Further, after the replacement of the inductor 33 is completed, the center frequency and the bandwidth of the pass band are made closer to the optimum state by using the characteristic correction pattern 182 based on the measurement result of the filter characteristic. For example, as shown in FIG. 7I, the characteristic correction pattern 182 located at the open ends of the resonance electrode patterns 161a and 161b is separated from the ground pattern 181 to bring the filter characteristic of the bandpass filter 10 closer to the desired filter characteristic.

  In the filter characteristic setting method shown in FIG. 7, a process of selectively separating the characteristic correction pattern 182 from the ground pattern 181 is performed before and after the capacitors 32a and 32b and the inductor 33 are mounted. did. However, if the desired filter characteristics can be obtained, the characteristic correction pattern 182 may be selectively separated from the ground pattern 181 after the capacitors 32a and 32b and the inductor 33 are placed.

  As described above, the filter characteristic can be corrected by selectively separating the characteristic correction pattern 182 from the ground pattern 181, thereby bringing the filter characteristic closer to the desired filter characteristic as compared with the case where only the chip parts are replaced. be able to. Further, even if characteristic variations of chip parts or the like occur, the filter characteristics can be brought close to desired filter characteristics using the characteristic correction pattern 182. In addition, since the characteristic correction pattern can be selectively separated from the ground pattern to correct the filter characteristic, there is no need to redesign the bandpass filter or add a matching circuit, and the bandpass filter with a short TAT can be easily reduced. Can be provided. In addition, it is possible to reduce the occurrence of defective products in which desired filter characteristics cannot be obtained.

  Furthermore, since the capacitors 31a and 31b are connected between the open ends of the resonant electrode patterns 161a and 161b and the ground, even if the length of the resonant electrode patterns 161a and 161b is shorter than a quarter wavelength of the center frequency of the passband, Desired filter characteristics can be obtained. In addition, the resonance electrode patterns 161a and 161b are formed in a meander shape or a spiral shape, and an inductor is provided between the input and output terminals, and the inductance of the inductor is varied to adjust the pass band in the filter characteristics. Further, the band pass filter can be further reduced in size, and desired filter characteristics can be obtained.

  By the way, the characteristic correction pattern 182 may be provided on the resonance electrode patterns 161a and 161b, and one end may be open and the other end may be grounded. The shape is not limited to a plurality of protruding shapes. For example, as shown in FIG. 8, one or a plurality of T-shaped characteristic correction patterns may protrude from the ground pattern 181.

  Further, as shown in FIG. 9, the characteristic correction pattern 182 may be formed separately from the ground pattern 181, and a switch 41 for connecting or disconnecting the ground pattern 181 and the characteristic correction pattern 182 may be provided. In this case, one contact terminal of the switch 41 is connected to the ground pattern 181, and the other contact terminal is connected to the characteristic correction pattern 182. Further, the control terminal of the switch 41 is connected to the drive signal pattern 187, and the contact terminals of the switch 41 are connected or disconnected by the drive signal pressure supplied through the drive signal pattern 187.

  The switch 41 uses a broadband switch MMIC (Monolithic microwave Integrated Circuit) configured using a MEMS (Micro Electro Mechanical System) switch element or gallium arsenide (GaAs), thereby increasing the size of the bandpass filter 10. Can be prevented.

  FIG. 10 is a schematic configuration of a main part of the MEMS switch element, and FIG. 11 is a schematic cross-sectional view at the position B-B ′ in FIG. 10. The MEMS switch element includes a substrate 51 formed in a state where the first and second control electrode patterns 501 and 502 and the first and second fixed contact electrode patterns 503 and 504 are insulated from each other; One end of the control electrode pattern 501 is fixed to a cantilever 52 made of a flexible thin plate-like dielectric material supported in a cantilevered state.

  The cantilever 52 is provided with a counter electrode pattern 521 that is electrically connected to the first control electrode pattern 501 and extends to a position facing the second control electrode pattern 502. Further, a movable segment 522 is provided on the free end side of the cantilever 52 so as to face both the first and second fixed contact electrode patterns 503 and 504.

  In the MEMS switch element 50 having such a structure, the counter electrode pattern 521 connected to the first control electrode pattern 501 and the first electrode pattern 521 are connected by the drive voltage applied between the first and second control electrode patterns 501 and 502. An electrostatic attractive force is generated between the two control electrode patterns 502. The cantilever 52 of the cantilever support structure is bent by this suction force, and the movable piece 522 provided at the free end is brought into contact with the first and second fixed contact electrode patterns 503 and 504, whereby the first and second The second fixed contact electrode patterns 503 and 504 are connected. When the application of the drive voltage is stopped and the generation of the electrostatic attractive force between the counter electrode pattern 521 connected to the first control electrode pattern 501 and the second control electrode pattern 502 is finished, The cantilever 52 of the holding support structure returns to the initial state, and the movable piece 522 provided at the free end is separated from the first and second fixed contact electrode patterns 503 and 504 and between the fixed contact electrode patterns 503 and 504. Not connected. Therefore, for example, the first fixed contact electrode pattern 503 is the characteristic correction pattern 182, the second fixed contact electrode pattern 504 and the first control electrode pattern are the ground pattern 181, and the second control electrode pattern 502 is the drive signal pattern 187. Since the characteristic correction pattern 182 can be set to the grounded state or the non-grounded state by the drive voltage supplied from the drive signal pattern 187, the characteristic correction pattern 182 is selectively selected from the ground pattern 181 by the switch 41. Can be separated. As described above, the characteristic correction pattern 182 can be separated from the ground pattern 181 by controlling the switch 41, so that the characteristic correction pattern 182 can be easily separated. In addition, the filter characteristics can be easily corrected. Furthermore, the filter characteristics can be corrected even after the band pass filter is incorporated.

  FIG. 12 shows an embodiment of the band pass filter 10. The resonance electrode patterns 161a and 161b have a length TL of 500 μm, the resonance electrode patterns 161a and 161b have a wiring width W of 50 μm, the meander-shaped resonance electrode patterns 161a and 161b have a pattern interval S of 110 μm, and the resonance electrode pattern 161a (161b ) To the slot end, the width SL1 is 200 μm, the width SL2 is 300 μm, the width SL3 is 50 μm, the gap width GP1 between the tip of the characteristic correction pattern 182 and the ground pattern 181 and the adjacent characteristic correction pattern 182 is 50 μm, The pattern width WG of the characteristic correction pattern 182 is set to 70 μm. The first conductor layer 11 and the second conductor layer 13 have a thickness of 20 μm, the third conductor layer 16 has a thickness of 3 μm, the fourth conductor layer 18 has a thickness of 10 μm, and the first dielectric layer 12 has a thickness of 400 μm. The dielectric constant is 3.1, the second dielectric layer 14 is 20 μm thick and the dielectric constant is 3.8, and the third dielectric layer 15 and the fourth dielectric layer 17 are 11 μm thick and the dielectric constant is 2.6. Note that a resist layer having a thickness of 20 μm and a dielectric constant of 4.3 is provided on both surfaces of a substrate on which a conductor layer and a dielectric layer are laminated.

  In the bandpass filter 10 configured as described above, when the capacitance C1 of the capacitors 31a and 31b is 8 pF, the capacitance C2 of the capacitors 32a and 32b is 20 pF, and the inductance L1 of the inductor 33 is 5.5 nH, the filter characteristics. Is the characteristic indicated by the solid line in FIG. Further, when the capacitance C1 of the capacitors 31a and 31b is 8 pF, the capacitance C2 of the capacitors 32a and 32b is 15 pF, and the inductance L1 of the inductor 33 is 4.5 nH, the characteristics of the broken line are obtained. The notch frequency of the stop band changes.

  Further, when the capacitance C1 of the capacitors 31a and 31b is 8 pF, the capacitance C2 of the capacitors 32a and 32b is 20 pF, the inductance L1 of the inductor 33 is 5.5 nH, and the number of separations of the characteristic correction pattern 182 is changed, for example, FIG. As shown by 14 solid lines, broken lines, or alternate long and short dash lines, the pass band slightly changes. For this reason, the characteristic correction pattern 182 is selectively disconnected from the ground pattern 181 in accordance with the measurement result of the filter characteristic performed using the probe, so that only the capacitors 32a and 32b and the inductor 33 are replaced. As compared with the case of setting, the filter characteristics can be made closer to the desired filter characteristics.

  As described above, the band-pass filter according to the present invention is useful for band-pass processing of high-frequency signals, and is applied to downsizing the band-pass filter and improving the accuracy of filter characteristics.

It is a figure which shows the equivalent circuit of a bandpass filter. It is a top view of a band pass filter. It is the cross-sectional schematic of A-A 'position. It is a disassembled perspective view of a band pass filter. It is a figure which shows an equivalent circuit when a characteristic correction pattern is provided. It is a figure which shows a state when one probe is connected. It is a figure for demonstrating the setting method of a filter characteristic. It is a figure which shows the other structure of a band pass filter. It is a figure which shows the other structure of a band pass filter. It is a figure which shows the principal part schematic structure of a MEMS switch element. It is a cross-sectional schematic diagram of a B-B 'position. It is a figure which shows the Example of a band pass filter. It is a figure which shows the filter characteristic of an Example. It is a figure which shows the filter characteristic when cut | disconnecting a characteristic correction pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 ... Collective substrate, 10 ... Band pass filter, 11 ... 1st conductor layer, 12 ... 1st dielectric material layer, 13 ... 2nd conductor layer, 14 ... 2nd dielectric material Body layer 15... 3rd dielectric layer 16... 3rd conductor layer 17... 4th dielectric layer 18... 4th conductor layer 31 a, 31 b, 32 a, 32 b. · Capacitor, 33 ··· Inductor, 41 ··· Switch, 50 ··· MEMS switch element, 51 ··· Board, 52 · · · Cantilever, 70, 71a, 71b, 72a, 72b, 73a, 73b Probe, 121, 151, 171, 172a, 172b, 173a, 173b ... via, 161a, 161b ... resonance electrode pattern, 162,181 ... grounding pattern, 182 ... characteristic correction pattern, 183a, 183b, 184a, 184b ... connection pattern 185a to 185e ... probe ground pattern, 187 ... drive signal pattern, 311s ... wiring film, 501, 502 ... control electrode pattern, 503, 504 ... fixed contact electrode pattern, 521 ..Counter electrode pattern, 522, movable section

Claims (11)

A ground conductor layer is formed on one side of a laminated substrate formed by laminating a plurality of dielectric layers and conductor layers, one end being a short-circuited end connected to the ground conductor layer and the other end being an open end A resonance pattern conductor layer having a resonance electrode is provided to face the ground conductor layer through the dielectric layer, and an open end side of the resonance electrode is connected to an input / output terminal, and one of the input / output terminals is connected to the input / output terminal. In a band pass filter that passes a signal of a desired frequency band from an input signal and outputs the signal from the other input / output terminal,
A band pass filter characterized in that one or a plurality of characteristic correction patterns protruding in a stub shape or a T shape from a ground pattern connected to the ground conductor layer are provided on the resonance electrode via a dielectric layer. . 2. The plurality of characteristic correction patterns are protruded through respective switches, and the characteristic correction patterns connected to the ground pattern can be selected by controlling the switches. Bandpass filter. 2. The band-pass filter according to claim 1, wherein one terminal of a capacitor is connected to the open end of the resonance electrode, and the other terminal of the capacitor is grounded. The band pass filter according to claim 1, wherein a capacitor is provided between an open end of the resonance electrode and the input / output terminal connected to the open end. 2. The band pass filter according to claim 1, wherein the resonance electrode is formed in a meander shape or a spiral shape. 6. The bandpass filter according to claim 5, wherein an inductor is provided between the input / output terminals. A ground conductor layer is formed on one side of a laminated substrate formed by laminating a plurality of dielectric layers and conductor layers, one end being a short-circuited end connected to the ground conductor layer and the other end being an open end A resonance pattern conductor layer having a resonance electrode is provided to face the ground conductor layer through the dielectric layer, and an open end side of the resonance electrode is connected to an input / output terminal, and one of the input / output terminals is connected to the input / output terminal. In a band pass filter that passes a signal of a desired frequency band from an input signal and outputs the signal from the other input / output terminal,
A plurality of characteristic correction patterns protruding in a stub shape or a T shape from a ground pattern connected to the ground conductor layer are provided on the resonance electrode via a dielectric layer,
A filter characteristic setting method, wherein the characteristic correction pattern is selectively separated from the ground pattern so as to obtain a desired filter characteristic. 8. The filter characteristic setting method according to claim 7, wherein each of the plurality of characteristic correction patterns protrudes through a switch, and the switch is controlled to separate the characteristic correction pattern from the ground pattern. 8. The filter according to claim 7, wherein one terminal of a capacitor is connected to an open end of the resonance electrode, and the other terminal of the capacitor is grounded to set a center frequency of a pass band in the filter characteristic. Characteristic setting method. A capacitor is provided between the open end of the resonance electrode and the input / output terminal connected to the open end, and the capacitance of the capacitor is adjusted to adjust the notch frequency of the stop band in the filter characteristics. The filter characteristic setting method according to claim 7. 8. The pre-resonant electrode is formed in a meander shape or a spiral shape, an inductor is provided between the input and output terminals, and an inductance of the inductor is varied to adjust a pass band in the filter characteristic. The filter characteristic setting method described.

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