JP2005311979A - Band filter and high frequency module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a band filter which has excellent filter characteristics, reduces costs and can be miniaturized, and a high frequency module. <P>SOLUTION: A microstrip line type or strip line type resonator wherein one terminal of resonant electrodes 34a, 34b is grounded and another terminal becomes an open terminal, is formed on a laminated substrate 30. An RFIC 20 is placed on the laminated substrate 30. In the RFIC 20, a filter characteristic adjusting section 11 is formed as a concentrated constant circuit for adjusting filter characteristics, and the filter characteristic adjusting section 11 and the open terminal of the resonant electrodes 34a, 34b are connected to comprise a band filter. Furthermore, the RFIC 20 comprises a high frequency signal processing circuit 25 comprised of the microstrip line type or strip line type resonator and the filter characteristic adjusting section 11 and connected to the band filter. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bandpass filter and a high frequency module. Specifically, a semiconductor chip is mounted on a laminated substrate on which a microstrip line or a strip line type resonator in which one end of a resonance electrode is grounded and the other end is an open end, Is formed with a lumped constant circuit that is connected to the open end of the filter and adjusts the filter characteristics. Further, the semiconductor chip is provided with a high-frequency signal processing circuit connected to a band-pass filter composed of a microstrip line or strip line type resonator and a lumped constant circuit.

  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.

  In an apparatus used in such a communication system, as shown in FIG. 7, as an RF input / output stage, for processing a signal obtained by receiving high-frequency radio waves, generating a signal to be transmitted as high-frequency radio waves, and the like An integrated circuit for high frequency signal processing (hereinafter referred to as “RFIC”) 100 is provided. In addition, a band filter 101 that passes a signal in a desired band is provided between the RFIC 100 and the signal input / output terminal 102 connected to the antenna. If the impedances of the RFIC 100 and the band-pass filter 101 do not match, a matching circuit is provided to reduce loss.

  The band filter 101 is designed as a distributed constant circuit in order to pass a signal in a desired band from a high frequency signal. For example, as shown in Patent Document 1, a triplate structure filter is formed using a pair of parallel conductor patterns.

JP 2000-252716 A

  By the way, if the RFIC and the band filter having good characteristics are individually provided, the occupied area becomes large and the device cannot be downsized. Furthermore, since the number of parts increases, the cost increases.

  In order to reduce the size, for example, when a resonator is formed inside the RFIC and a bandpass filter is formed, the RFIC has a thin wiring and a large resistance value. Therefore, a resonance electrode is provided in the RFIC. Even if the resonator is configured, the Q (quality factor) value of the resonator is low and the coupling is weak, so that the loss in the bandpass filter becomes large. Furthermore, since the space is limited inside the RFIC, it is impossible to increase the resonance electrode to increase the Q value or strengthen the coupling. For this reason, it is difficult to build a bandpass filter with good characteristics inside the RFIC.

  Accordingly, the present invention provides a bandpass filter having good filter characteristics, low cost and capable of being downsized, and a high frequency module using the same.

  In the bandpass filter according to the present invention, a semiconductor chip is mounted on a laminated substrate on which a microstrip line or a stripline type resonator in which one end of a resonance electrode is grounded and the other end is an open end is formed. Is formed with a lumped constant circuit that is connected to the open end of the resonance electrode to adjust the filter characteristics.

  In addition, the high-frequency module has a semiconductor chip mounted on a laminated substrate on which a microstrip line or a strip line type resonator in which one end of a resonance electrode is grounded and the other end is an open end, A lumped constant circuit that is connected to the open end of the resonant electrode to adjust the filter characteristics, and a high-frequency signal processing circuit that is connected to a band-pass filter composed of a microstripline or stripline resonator and a lumped constant circuit It is.

  In the present invention, a microstrip line or a strip line type resonator in which one end of a resonance electrode is grounded and the other end is an open end is formed on a multilayer substrate, and a semiconductor chip is placed on the multilayer substrate. The In a semiconductor chip, for example, a capacitor having one end connected to the open end of the resonance electrode and the other end serving as a signal input / output end, and / or a capacitor having one end connected to the open end of the resonance electrode and the other end grounded Is formed, and the filter characteristics are adjusted by the lumped constant circuit. The capacitor of the lumped constant circuit has a circuit operation different from the adjustment of the filter characteristics. For example, a capacitor having one end connected to the open end and the other end serving as a signal input / output end is used as a decoupling capacitor. Further, the lumped constant circuit is provided with a capacitor having one end connected to the signal input end and the other end connected to the signal output end. The semiconductor chip is provided with a high-frequency signal processing circuit connected to a band-pass filter composed of a microstrip line or strip line type resonator and a lumped constant circuit.

  According to the present invention, a semiconductor chip is placed on a laminated substrate on which a microstrip line or a strip line type resonator in which one end of a resonance electrode is grounded and the other end is an open end is formed. Is formed with a lumped constant circuit that is connected to the open end of the resonance electrode to adjust the filter characteristics. Thus, by forming the resonator on the multilayer substrate, the Q value of the resonator can be increased, and the loss of the bandpass filter can be reduced. In addition, since the lumped constant circuit for adjusting the filter characteristics is formed in the semiconductor chip, the number of components is reduced, the occupied area is reduced, and the cost can be reduced.

  The lumped constant circuit is composed of a capacitor having one end connected to the open end and the other end serving as a signal input / output end, and / or a capacitor having one end connected to the open end and the other end grounded. . For this reason, it becomes possible to adjust the capacitance of the capacitor to move the resonance frequency to the low frequency side or the high frequency side, and to obtain desired filter characteristics.

  Further, since the capacitor of the lumped constant circuit is used for circuit operation different from the adjustment of the filter characteristics, the number of capacitors formed in the semiconductor chip can be reduced. Furthermore, since the lumped constant circuit is provided with a capacitor having one end connected to the signal input end and the other end connected to the signal output end, the frequency trapped by this capacitor is adjusted to improve the filter characteristics. be able to.

  Furthermore, since the semiconductor chip is provided with a high-frequency signal processing circuit connected to a band-strip filter composed of a microstripline or stripline-type resonator and a lumped constant circuit, the band-pass filter and the high-frequency signal processing circuit are integrally formed. As a result, the high-frequency module can be assembled easily, at low cost, and downsized.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an equivalent circuit of a bandpass filter. The band filter 10 includes a filter characteristic adjustment unit 11 that is a lumped constant circuit and a resonator 12 that is a distributed constant circuit.

  The signal input / output terminal 14a is connected to one terminal of a resonance electrode 34a constituting the resonator 12 via, for example, a capacitor 21a (electrostatic capacity C1) constituting the filter characteristic adjusting unit 11, and this resonance electrode 34a. The other terminal is grounded. The signal input / output terminal 14b is connected to one terminal of the resonance electrode 34b via the capacitor 21b (capacitance C1), and the other terminal of the resonance electrode 34b is grounded. One terminal of a capacitor 22a (capacitance C2) is connected to a connection portion between the capacitor 21a and the resonance electrode 34a, and the other terminal of the capacitor 22a is grounded. One terminal of a capacitor 22b (capacitance C2) is connected to a connection portion between the capacitor 21b and the resonance electrode 34b, and the other terminal of the capacitor 22b is grounded. A capacitor 23 (capacitance C3) is connected between the signal input / output terminal 14a and the signal input / output terminal 14b. The resonance electrode 34a and the resonance electrode 34b are provided in parallel with a distance S between the resonance electrodes, and are coupled by a mutual inductance M.

  By adjusting the lengths of the resonance electrodes 34a and 34b in the longitudinal direction and the capacitances C1, C2, and C3 of the capacitors, for example, when the high frequency signal RFin is input from the signal input / output terminal 14a, the high frequency signal RFin is filtered. Processing is performed, and the signal RFout through which the signal in the desired frequency band is passed can be extracted from the signal input / output terminal 14b.

  Here, when the electrostatic capacitance C1 and the electrostatic capacitance C2 are increased, the resonance frequency of the resonator 12 configured using the resonance electrodes 34a and 34b can be moved to the low frequency side. That is, the pass band of the band filter 10 can be moved to the low frequency side. Further, the resonance frequency can be moved to the high frequency side by reducing the capacitance C1 and the capacitance C2. That is, the pass band of the band filter 10 can be moved to the high frequency side.

  Further, the capacitor 23 functions as a trap. By increasing the capacitance C3 of the capacitor 23, the trapping frequency (notch point) can be moved to the low frequency side, and the capacitance C3 is reduced. Thus, the notch point can be moved to the high frequency side. For this reason, the filter characteristics are adjusted by adjusting the capacitance C3 so that the notch point is on the low frequency side or the high frequency side of the pass band and attenuating the components on the low frequency side or the high frequency side of the pass band. Can be made good.

  FIG. 2 shows the configuration of the band-pass filter 10, and the filter characteristic adjustment unit 11 configured by a lumped constant circuit is formed inside a semiconductor chip, for example, the RFIC 20. In addition, the resonator 12 which is a distributed constant circuit is formed on the laminated substrate 30 using an organic material mixed with polyimide, epoxy, or the like and glass or the like, or a low-temperature fired ceramic, and the RFIC 20 The band filter 10 is configured by connecting the filter characteristic adjusting unit 11 formed inside the RFIC 20 and the resonator 12 of the laminated substrate 30.

  The circuit element of the filter characteristic adjustment unit 11 formed inside the RFIC 20 is used not only for setting the filter characteristic of the band-pass filter 10 but also as a part of the internal circuit of the RFIC 20. For example, the terminal 15a connected to the capacitor 22a and the resonator connection terminal 24a, and the terminal 15b connected to the capacitor 22b and the resonator connection terminal 24b are power supply terminals. At this time, the capacitors 22a and 22b not only set the filter characteristics, but also operate as decoupling capacitors. Further, when a signal is input from the signal input / output terminal 24c, a signal from which the DC component is removed can be obtained from the terminal 15b. Therefore, the capacitor 21b is not only used for setting the filter characteristics but also as a capacitor for cutting the DC component. Will work.

  As described above, not only the capacitor of the filter characteristic adjusting unit 11 is used for setting the filter characteristic of the band-pass filter 10, but also the number of capacitors formed in the RFIC 20 can be reduced by using it as a part of the internal circuit of the RFIC 20. .

  The RFIC 20 includes a high-frequency signal processing circuit 25 that performs processing of a filtered high-frequency signal, generation processing of a high-frequency signal that performs filtering, and the like. The high-frequency signal processing circuit 25 is used as a signal input / output terminal 14a. By connecting to, a high-frequency module in which a band-pass filter is connected to the high-frequency signal processing circuit can be formed. The RFIC 20 is provided with a ground terminal 24d, and the ground terminal 24d is connected to a ground pad, which will be described later, so that the ground level of the RFIC 20 and the laminated substrate 30 is set to the same potential.

  3 is a plan view showing the configuration of the band-pass filter, FIG. 4 is a schematic sectional view taken along the line AA ′ of the band-pass filter 10 shown in FIG. 3, and FIG. 5 is an exploded perspective view of the band-pass filter 10. 3 to 5 show a case where a stripline type resonator is used.

  A first conductor layer 32 is formed on the first insulator layer 31, and a second insulator layer 33 is formed on the first conductor layer 32. Further, a second conductor layer 34 including resonance electrodes 34 a and 34 b is formed on the second insulator layer 33. The resonance electrodes 34a and 34b are provided in parallel with the resonance electrode interval S as described above.

  In the second insulator layer 33, a conductor layer connecting portion such as a via hole or a through hole (hereinafter simply referred to as “via”) is provided at a position corresponding to one end of the resonance electrode 34a. 41a is formed, and one end of the resonance electrode 34a is connected to the first conductor layer 32 by the via 41a. In addition, a via 41b is formed at a position corresponding to the end side of the resonance electrode 34b on the end side of the resonance electrode 34b that is equal to the end side of the resonance electrode 34a in which the via 41a is formed. Thus, one end side of the resonance electrode 34 b is connected to the first conductor layer 32.

  A third insulator layer 35 is formed on the second conductor layer 34, and a third conductor layer is formed on the third insulator layer 35. Furthermore, a fourth insulator layer 37 is formed on the third conductor layer 36. In the third insulator layer 35 and the fourth insulator layer 37, a via 42a is formed at a position corresponding to the other end side of the resonance electrode 34a. A via 42b is also formed at a position corresponding to the other end side of the resonance electrode 34b. The third conductor layer 36 is provided with an opening 36a at the position of the via 42a so that the third conductor layer 36 and the vias 42a and 42b are not electrically connected, and at the position of the via 42b. An opening 36b is provided.

  A fourth conductor layer 38 is formed on the fourth insulator layer 37. The fourth conductor layer 38 is provided with pads for electrically connecting the RCIF 20 and the resonance electrodes 34 a and 34 b provided on the multilayer substrate 30. The pad 38 a is for connecting the via 42 a and the resonator connection terminal 24 a of the RFIC 20. The pad 38 b is for connecting the via 42 b and the resonator connection terminal 24 b of the RFIC 20. The pad 38c is connected to the signal input / output terminal 24c of the RFIC 20, and the pad 38c is used as the signal input / output terminal 14b.

  The laminated substrate 30 has vias 43 for connecting the ground pads 38 d of the first conductor layer 32, the third conductor layer 36, and the fourth conductor layer 38 with the second insulator layer 33 and the third insulator layer 35. And the fourth insulator layer 37. Therefore, by connecting the ground terminal 24d of the RFIC 20 and the ground pad 38d of the fourth conductor layer 38, the first conductor layer 32 and the third conductor layer 36 of the multilayer substrate 30 are set to the same potential as the ground level of the RFIC 20. The stripline resonator 12 can be configured by the resonance electrodes 34a and 34b.

  The fourth conductor layer 38 is provided with a pad 38e connected to a pattern for connecting the RFIC 20 to another circuit, a pattern for supplying power to the RFIC 20, and the like, and the pad 38e and the terminal 24e of the RFIC 20 are connected. It is good to do.

  The RFIC 20 placed on the multilayer substrate 30 may be a bare chip or packaged as long as it can be connected to the pads constituting the fourth conductor layer 38 of the multilayer substrate 30.

  In the above embodiment, the stripline resonator is used. However, the first insulator layer 31, the first conductor layer 32, and the second insulator layer 33 are not provided, and the resonance electrodes 34a and 34b are not provided. If the end portion is connected to the third conductor layer 36 instead of the first conductor layer 32, a band-pass filter using a microstrip line type resonator can be configured.

  Further, the configuration of the resonator is not limited to the case where the resonance electrodes 34a and 34b are formed with a predetermined interval in the substrate surface direction, and three or more resonance electrodes are formed in the substrate surface direction, A resonator may be configured even if electrodes are provided in the substrate stacking direction.

  Thus, by forming the resonator on the multilayer substrate, the Q value of the resonator can be increased, and a bandpass filter with less loss can be provided. In addition, since the lumped constant circuit for adjusting the filter characteristics is formed in the semiconductor chip, the number of parts of the band-pass filter is reduced, the occupied area is reduced, and the cost and size can be reduced.

  In addition, the semiconductor chip is provided with a high frequency signal processing circuit connected to a band-pass filter composed of a microstripline or stripline type resonator and a lumped constant circuit. As a result, the band-pass filter and the high-frequency signal processing circuit can be integrally formed, and the high-frequency module can be easily assembled, reduced in cost, and reduced in size.

  In the bandpass filter 10 shown in FIG. 1, the wiring length L of the resonant electrode is 3000 μm, the wiring width W of the resonant electrode is 300 μm, the spacing S of the resonant electrodes is 200 μm, and the capacitors 21a, 21b, 22a, 22b, 23 are made of tantalum oxide TaO. The capacitance C1 of the capacitor is 3.5 pF, the capacitance C2 is 5 pF, and the capacitance C3 is 1.3 pF.

  The first insulator layer 31, the second insulator layer 33, and the third insulator layer 35 have a layer thickness of 50 μm, a relative dielectric constant of 4.0, and a dielectric loss tangent tan δ of 0.009. The fourth insulator layer 37 has a layer thickness of 50 μm, a relative dielectric constant of 4.2, and a dielectric loss tangent tan δ of 0.009. The first conductor layer 32, the second conductor layer 34, and the third conductor layer 36 are 20 μm thick, and the fourth conductor layer 38 is 10 μm thick.

  When the band filter 10 is configured as described above, the electromagnetic field simulation result shows the characteristics of the band filter having a pass band of about 2.3 GHz to 2.6 GHz as shown in FIG. In addition, the broken line in FIG. 6 has shown the reflection characteristic.

  As described above, the present invention is useful as a band-pass filter or a high-frequency module using a high-frequency signal, and is applied to reducing the cost and size of equipment.

It is a figure which shows the equivalent circuit of a bandpass filter. It is a figure which shows the structure of a band filter. It is a top view of a bandpass 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 the filter characteristic of a band filter. It is a figure which shows the structure of RF input / output stage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,101 ... Band-pass filter, 11 ... Filter characteristic adjustment part, 12 ... Resonator, 14a, 14b, 24c, 102 ... Signal input / output terminal, 20,100 ... RFIC, 24a, 24b ... resonator connection terminal, 30 ... laminated substrate, 31 ... first insulator layer, 32 ... first conductor layer, 33 ... second insulator layer, 34 ... first 2 conductor layers, 34a, 34b ... resonant electrodes, 35 ... third insulator layer, 36 ... third conductor layer, 36a, 36b ... opening, 37 ... fourth insulator layer 38a, 38b, 38c ... pads, 38d ... ground pads, 41a, 41b, 42a, 42b, 43 ... via holes.

Claims (6)

A semiconductor chip is mounted on a laminated substrate on which a microstrip line or a strip line type resonator in which one end of a resonance electrode is grounded and the other end is an open end,
A bandpass filter characterized in that a lumped constant circuit for adjusting a filter characteristic is formed on the semiconductor chip and connected to an open end of the resonance electrode. The lumped constant circuit includes a capacitor having one end connected to the open end and the other end serving as a signal input / output end, and / or a capacitor having one end connected to the open end and the other end grounded. The band-pass filter according to claim 1. 3. The bandpass filter according to claim 2, wherein the capacitor of the lumped constant circuit is used for a circuit operation different from the adjustment of the filter characteristic. 4. The bandpass filter according to claim 3, wherein a capacitor whose one end is connected to an open end and whose other end is a signal input / output end is used as a decoupling capacitor. 3. The bandpass filter according to claim 2, wherein the lumped constant circuit includes a capacitor having one end connected to a signal input end and the other end connected to a signal output end. A semiconductor chip is mounted on a laminated substrate on which a microstrip line or a strip line type resonator in which one end of a resonance electrode is grounded and the other end is an open end,
The semiconductor chip is connected to a lumped constant circuit that is connected to the open end of the resonant electrode to adjust filter characteristics, and to a bandpass filter that includes the microstripline or stripline type resonator and the lumped constant circuit. A high frequency module comprising a high frequency signal processing circuit.

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