JP2010147589A - High frequency circuit, high frequency component, and communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain both of improvement in the reception sensitivity and higher attenuation amount in the region out of the pass band, and make a smaller product, in a high frequency circuit equipped with a low noise amplifier, a high frequency component and communication equipment. <P>SOLUTION: The high frequency circuit includes a first band pass filter connected to the input side of a low noise amplifier for amplifying a signal in a frequency band of a first communication system and a second band pass filter connected to the output side of the low noise amplifier. At the frequency band of the first communication system, the insertion loss of the first band pass filter is smaller than the insertion loss of the second band pass filter. At at least a part of a stop band out of the pass band, the attenuation amount of the second band pass filter is larger than the attenuation amount of the first band pass filter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high-frequency circuit, a high-frequency component, and a communication device used for signal transmission such as wireless transmission such as a mobile phone, wireless LAN, WiMAX, and next-generation PHS.

  In a communication device, a received signal input via an antenna has a very low signal level, and therefore, the received signal is amplified by a low noise amplifier on the way to be output to the RFIC unit. At this time, since signals other than the communication band of the received signal are unnecessary, it is necessary to attenuate unnecessary signals using a low-pass filter, a high-pass filter, or a band-pass filter. This is because when an unnecessary signal is erroneously input to the RFIC unit, the RFIC unit may malfunction. Further, it is possible to improve reception sensitivity by attenuating unnecessary signals. In general, a bandpass filter circuit is often used as a method for attenuating unnecessary signals. Among the bandpass filter circuits, a circuit as shown in Patent Document 1 has been proposed for the purpose of further attenuating unnecessary signals.

In addition, it is desirable that the received signal input via the antenna is input to the low noise amplifier so as not to deteriorate the S / N ratio as much as possible. The degree of deterioration of the S / N ratio can be expressed by a noise figure. Noise figure F _tot of the entire circuit including the low-noise amplifier, the input side of the insertion loss of the low-noise amplifier L _{in the} output side of the insertion loss of the low-noise amplifier L _out, the noise figure and gain of the low noise amplifier When expressed in _FLNA and _GLNA ,
F _tot = L _in + (F _LNA −1) / G _LNA + (L _out −1) / G _LNA
It can be expressed as. That is, to improve the noise figure of the entire circuit, it is very effective to reduce the insertion loss on the input side of the low noise amplifier. Therefore, as a method for increasing the reception sensitivity, it is important to reduce the insertion loss on the input side of the low-noise amplifier as much as possible. To realize this, a circuit as shown in Patent Document 2 has been proposed.

  In FIG. 1 of Patent Document 1, a surface acoustic wave filter 12 is connected to the input side of the low noise amplifier 14, and an LC filter 16 is connected to the output side. The surface acoustic wave filter 12 is connected to remove signals outside the pass band, and the LC filter is connected to remove image signals from the received signal. By providing a filter to remove signals outside the pass band on the input / output side, it is possible to obtain a sufficient amount of attenuation for signals other than the pass band.

  In Patent Document 2, the SW 101 for switching the communication path is provided in the circuit. When it is desired to improve the reception sensitivity, a circuit C2 in which no bandpass filter is connected to the input / output side of the low noise amplifier 105a is used. When an attenuation amount of a signal outside the pass band is necessary, a circuit C1 in which band-pass filters 104a and 104c are connected to the input / output side of the low noise amplifier 104b is used. This makes it possible to achieve both reception sensitivity and attenuation in one communication device.

JP 2003-69439 A JP 2003-8459 A

  In a receiving circuit having a low-noise amplifier in the technical field described above, high receiving sensitivity and high attenuation of unnecessary signals are required. However, in the circuit described in Patent Document 1, improvement in reception sensitivity is not considered. In the invention described in Patent Document 2, it is possible to achieve both high reception sensitivity and high attenuation of unnecessary signals as a communication device, but it is necessary to newly configure a bypass circuit. For this reason, it is necessary to newly install semiconductor elements and low-noise amplifiers necessary for the switch circuit on a multilayer substrate, which hinders the miniaturization of high-frequency components and the like.

  In general, when the attenuation amount outside the band is increased, the insertion loss is also deteriorated. For this reason, when the band-pass filter circuit is connected only to the input side, a high attenuation can be ensured, but the insertion loss on the input side becomes extremely large, resulting in a problem that the reception sensitivity is remarkably deteriorated. When connected to the output side only, it is possible to prevent the reception sensitivity from deteriorating compared to when connected to the input side, but unnecessary signals are input to the low noise amplifier without being attenuated. When a strong signal outside the communication band is input via the antenna, the low-noise amplifier may be saturated with a signal outside the communication band, and the passband signal may not be amplified. For this reason, signals necessary for the communication system are not normally transmitted, which adversely affects communication equipment. Also, since the insertion loss on the output side becomes large, it is necessary to use a high gain amplifier in order to obtain a predetermined output power, which is disadvantageous for improving the receiving sensitivity and reducing the size.

  In view of the above points, the present invention provides a high-frequency circuit, a high-frequency component, and a communication device having a low-noise amplifier that achieves both improved reception sensitivity and high attenuation outside the passband, and enables downsizing. Objective.

  The high-frequency component according to the present invention includes a low-noise amplifier that amplifies a reception signal of the first communication system, and a first connected to the input side of the low-noise amplifier with the frequency band of the first communication system as a pass band. And a second band-pass filter connected to the output side of the low-noise amplifier with the frequency band of the first communication system as a pass band, In the frequency band of the communication system, the insertion loss of the first bandpass filter is smaller than the insertion loss of the second bandpass filter, and the second bandpass filter has at least a part of the stopband outside the passband. The attenuation amount of the first bandpass filter is larger than the attenuation amount of the first bandpass filter. With this configuration, it is possible to achieve both improvement in reception sensitivity and high attenuation outside the passband while keeping the high-frequency circuit small.

  The high-frequency circuit is a high-frequency component configured by using a laminated body in which an electrode pattern is formed on a plurality of dielectric layers, and an element mounted on the surface of the laminated body. The second band-pass filter is preferably an LC filter configured using an inductance element and a capacitance element formed in the multilayer body. By using such an LC filter, it is possible to configure the filter at a low cost and contribute to miniaturization of the high-frequency component.

  Further, in the high-frequency component, each of the first and second bandpass filters has a structure in which a plurality of resonance lines arranged in parallel in the laminate are electromagnetically coupled, and the second bandpass filter It is preferable that the number of resonance lines is equal to or greater than the number of resonance lines of the first bandpass filter.

  Furthermore, in the high-frequency component, the plurality of resonance lines of the first bandpass filter and the plurality of resonance lines of the second bandpass filter are substantially linear, and the first bandpass filter It is preferable that the longitudinal direction of the plurality of resonance lines and the longitudinal direction of the plurality of resonance lines of the second bandpass filter are the same. Such a configuration is advantageous for reducing the area occupied by the bandpass filter.

  A communication apparatus according to the present invention is characterized by using any of the high-frequency components.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide a small high frequency circuit, a high frequency component, and a communication apparatus, ensuring a receiving sensitivity improvement and the high attenuation amount of an unnecessary signal.

  A high-frequency circuit according to the present invention includes a low-noise amplifier that amplifies a received signal of a first communication system and a passband that is a frequency band of the first communication system, and is connected to an input side of the low-noise amplifier. And a second bandpass filter connected to the output side of the low noise amplifier with a frequency band of the first communication system as a passband. Further, in the frequency band of the first communication system, the insertion loss of the first bandpass filter is smaller than the insertion loss of the second bandpass filter, and at least a part of the stopband outside the passband The attenuation amount of the second bandpass filter is larger than the attenuation amount of the first bandpass filter. Such high-frequency circuits are used for signal transmission in communication systems such as mobile phones, wireless LANs, WiMAX, and next-generation PHS. Specifically, the present invention is applied to, for example, a reception module and a transmission / reception module in wireless transmission. Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.

[First Embodiment]
A first embodiment is shown in FIG. In FIG. 1, the signal of the first communication system received from the antenna is arranged on the antenna terminal ANT1, the first bandpass filter BPF1 arranged on the input side of the low noise amplifier LNA1, the low noise amplifier LNA1, and arranged on the output side. An equivalent circuit in the case where a signal is transmitted to the RFIC circuit through the second band-pass filter BPF2 is shown. About parts other than low noise amplifier LNA1, band pass filter BPF1, and band pass filter BPF2, it can change suitably also including the presence or absence. For example, in addition to the equivalent circuit of FIG. 1, a switch circuit or the like for switching the transmission / reception signal path may be inserted between the antenna terminal ANT1 and the bandpass filter BPF1. Further, a mixer circuit or the like may be connected between the second band pass filter BPF2 arranged on the output side and the RFIC circuit.

Here, the high frequency characteristics of the first and second band-pass filters BPF1 and BPF2 connected to the input side and the output side are shown in FIG. The insertion loss of the first band pass filter BPF1 in the frequency band f ₁ of the _first communication system is IL ₁ , and the attenuation in the out-of-band stop band f ₂ (f ₃ ) is AT ₁ . Similarly the insertion loss in the frequency band _{f 1} of the first communication system of the second band-pass filter BPF2 and IL _2, the attenuation at out-of-band rejection band _f 2 _{(f 3)} and AT _2. The amplification factor of the low noise amplifier is G ₁ and the noise figure is N ₁ . Here, the band pass filters BPF1 and BPF2 before and after the low noise amplifier are designed so that the insertion loss level is IL ₁ <IL ₂ and the attenuation level outside the band is AT ₁ <AT ₂ . Such a relationship only needs to be satisfied in at least a part (f ₂ or f ₃ ) outside the pass band of the band pass filter. For example, if the bandwidth of the harmonics of a communication system that the bandwidth used for mobile phone use frequency band f _1, such as f _2, WLAN or WiMAX was f _3, in these bands, if so the relationship is satisfied Good.

FIG. 3 shows the high frequency characteristics of the high frequency circuit of this embodiment. Here, for comparison, the high-frequency characteristic (a) when only the input-side bandpass filter is connected, the high-frequency characteristic (b) when only the output-side bandpass filter is connected, and the input-side and output The high-frequency characteristics (c) when the side band-pass filter is replaced are shown for comparison. The high frequency characteristics of the high frequency circuit of this embodiment are represented by (d). Also, let AT _{3 be the} out-of-band attenuation required at the frequencies of f ₂ and f ₃ . Input, the case of connecting the band-pass filter only either one of the output (a) (b), the insertion loss is good, it is impossible to attenuation in the frequency band of f ₂ and f ₃ is below the target value .

Next, the noise figures N (c) and N (d) in the circuits (c) and (d) that can satisfy the attenuation amount are:
N (c) = IL ₂ + (N ₁ −1) / G ₁ + (IL ₁ −1) / G ₁
N (d) = IL ₁ + (N ₁ −1) / G ₁ + (IL ₂ −1) / G ₁
It can be expressed as. Comparing N (c) and N (d), the magnitude relationship between IL ₁ and IL ₂ is dominant in the magnitude relationship of the noise figure. Therefore, it is important to arrange the input-side and output-side band-pass filters as IL ₁ <IL ₂ , thereby providing a receiving circuit that secures an attenuation while suppressing deterioration in receiving sensitivity. That is, a low insertion loss type band-pass filter is arranged in the first band-pass filter to improve reception sensitivity. On the other hand, an unnecessary signal is sufficiently attenuated by disposing a high-attenuation type band-pass filter in the second band-pass filter provided on the output side of the low-noise amplifier. In the present invention, a special bypass circuit or the like is not necessary, and high-frequency components and communication equipment can be reduced in size. In addition, by reducing the number of necessary parts, it is possible to provide an inexpensive product.

  In the present embodiment, an LC filter, a surface acoustic wave filter, a dielectric filter, or the like may be used as the bandpass filter. In addition, a low-pass filter, a high-pass filter, or the like may be combined as long as the LC filter satisfies the characteristics. When the band-pass filter is composed of an LC filter, the high-frequency circuit is configured as a high-frequency component using a laminated body in which electrode patterns are formed on a plurality of dielectric layers and an element mounted on the surface of the laminated body. The In this case, the LC filter is configured using an inductance element and a capacitance element formed in the laminate. Since the LC filter is integrated with the high-frequency component together with other circuit elements, the high-frequency component can be miniaturized.

[Second Embodiment]
Next, a block circuit of the front end module 1 using the present invention will be described with reference to FIG. The front end module using the present invention has antenna terminals ANT1 and ANT2 connected to two antennas, a transmission terminal P1 / P2 (TX1) connected to a transmission circuit, and a first circuit connected to a reception circuit. The front end module has a receiving terminal P3 / P4 (RX1) and a second receiving terminal P5 / P6 (RX2), and has a so-called 1T2R (one transmission and two reception) structure. A part of the electrodes constituting the front end module is fabricated in a laminate (multilayer substrate), and a low noise amplifier, a GaAs switch constituting a switch circuit, and the like are mounted on the upper surface of the multilayer substrate.

  The transmission signal from the RFIC circuit 2 is input from the balanced-unbalanced conversion circuit BAL3, and unnecessary signals are attenuated by the bandpass filter BPF5, and then input to the amplifier PA. The amplified signal passes through a low-pass filter LPF that attenuates unnecessary harmonic signals, and further passes through a switch circuit SW1 and a high-pass filter HPF1, and is radiated from an antenna through an antenna terminal ANT1. The switch circuit SW1 controls the power supply voltage by switching so that the transmission path is turned on in the transmission mode. The high-pass filter HPF1 is arranged for ESD countermeasures.

  On the other hand, the received signal is input to the front end module via the antenna terminal ANT1 and the antenna terminal ANT2. The front-end module of this embodiment is compatible with MIMO that can use signals received simultaneously by a plurality of antennas. Therefore, the signal-to-noise ratio can be increased by increasing the number of signal propagation paths, and the signal quality can be improved. A signal input via the antenna terminal ANT1 passes through the high pass filter HPF1 and is input to the switch circuit SW1. At this time, the switch circuit SW1 controls the power supply voltage so that the reception path is turned on. The signal that has passed through the switch circuit passes through the bandpass filter BPF1, and after an unnecessary signal outside the communication band is attenuated, it is input to the low noise amplifier LNA1. The bandpass filter BPF2 connected to the output side can secure a sufficient amount of attenuation of unnecessary signals outside the passband. The received signal that has passed through the bandpass filter BPF1 is input to the RFIC circuit 2 via the balanced-unbalanced conversion circuit BAL2. Note that the transmission terminal and the reception terminal are not necessarily balanced terminals. Further, the configuration other than the low noise amplifier and the band pass filters before and after the low noise amplifier can be appropriately changed. Since the reception path from the second antenna terminal ANT2 to the reception terminal P5 / P6 (RX2) is the same as the reception path from the first antenna terminal ANT1 to the reception terminal P3 / P4 (RX1), description thereof is omitted.

  Next, FIG. 5 shows a perspective view of the front end module according to the present embodiment, which constitutes a high-frequency circuit from the antenna terminal to the transmission terminal and the reception terminal. The front end module is configured by using a laminated body in which an electrode pattern is formed on a dielectric layer using a conductive paste and laminated and integrated, and an element mounted on the surface of the laminated body. A GaAs switch, a low-noise amplifier, and a power amplifier constituting a switch circuit are mounted on the upper surface. In the present embodiment, all of the above active elements are bare chips, and the pads on the bare chips are connected to the electrodes on the laminated body by gold wires. By using a bare chip, the height and size can be reduced compared to the case of using a package product. A chip inductor, chip capacitor, and chip resistor are mounted on the upper surface as necessary. If possible, the element mounted on the upper surface may be designed by being embedded in the laminate.

  Next, an equivalent circuit of the reception circuit of the front end module is shown in FIG. Here, an equivalent circuit from the antenna terminal ANT1 to the reception terminal P3 / P4 (RX1) is shown. The antenna terminal ANT1 is connected to capacitors Ch1 to Ch5 formed inside the multilayer body and a high pass filter HPF1 designed by the transmission lines Lh1 to Lh3. By connecting the high-pass filter, the antenna terminal ANT1 can be opened in a DC manner, and a surge voltage entering from the antenna terminal ANT1 can be attenuated, so that the switch circuit can be prevented from being destroyed. Next, the transmission path and the reception path are switched by a GaAs switch. Although the SPDT switch is used in this embodiment, a DPDT switch, an SP3T switch, or the like may be used depending on the communication system.

  BPF1 (also referred to as BPFin) is connected between the switch circuit SW1 and the input side of the low noise amplifier LNA1. The BPFin has a resonator structure using two transmission lines LL1a to 1c and LL2a to 2c formed in the laminated body. One end of each resonator is connected to GND, and the other end has a ground capacitance by capacitive electrodes Cl1d and Cl2d. A DC cut capacitor constituted by Cl1a to Cl1c and Cl2a to Cl2c is connected to the input / output side of BPFin. Chip inductors Lin1 and Lin2 mounted on the upper surface of the multilayer body are connected between the DC cut capacitors Cl2a to Cl2c and the low noise amplifier LNA1 in order to achieve input matching. The input matching can be easily adjusted by changing the constant of the chip inductor.

  The low noise amplifier LNA1 is turned on / off by the control voltage Vb. Vdd (drain voltage) is normally applied to the low noise amplifier at 3.0 to 4.0 V. As the control voltage Vb, a voltage of about 2.0 to 3.0 V is applied when the received signal needs to be amplified, and the low noise amplifier is turned on. When Vb is in the off mode, the low noise amplifier is in the bypass mode. The bypass mode is used to prevent saturation of the low-noise amplifier when a high-power signal is input from the antenna. However, an LNA without the bypass mode may be used as necessary. A choke coil Lout1 and a noise cut capacitor Cout are connected to the Vdd terminal.

  The signal amplified by the low noise amplifier LNA1 passes through the inductor Lout2 for matching on the output side, and is input to the bandpass filter BPF2 (also referred to as BPFout). The BPFout has a resonator structure including two transmission lines LL3a to 3c and LL4a to 4c formed in the laminated body. One end of each resonator is connected to GND, and the other end has a ground capacitance by capacitive electrodes Cl3d and Cl4d. A DC cut capacitor constituted by Cl3a to Cl3c and Cl4a to Cl4c is connected to the input / output side of BPFout. Further, a capacitor Cl5 is connected to strengthen the coupling between the resonators. This makes it possible to increase the attenuation outside the passband. Further, the number of resonators by the transmission line may be three, and the attenuation outside the passband may be increased.

  The signal that has passed through the bandpass filter BPFout is converted into a balanced signal by the balanced-unbalanced conversion circuit BAL. The balanced-unbalanced conversion circuit is configured using transmission lines Lbal1, Lbal2, and Lbal3 formed in the laminated body. Lbal1 may include a transmission line that matches the bandpass filter BPFout and the balanced-unbalanced conversion circuit BAL. A capacitor Cbal mounted on the top surface of the multilayer body is connected between Lbal2 and Lbal3. The phase difference of the reception signals output to the reception terminals P3 / P4 can be adjusted by the capacitor Cbal. The reception terminals P3 / P4 are connected to the RFIC circuit unit. Since the balanced input / output has better noise resistance than the unbalanced input / output, the RFIC circuit section often has a balanced input and a balanced output. On the other hand, since the switch circuit and the low noise amplifier circuit unit are unbalanced devices, a balanced-unbalanced conversion circuit is often provided as an interface with the RFIC circuit unit. By designing the balanced-unbalanced conversion circuit inside the laminate, it is possible to reduce the size of the high-frequency component, and to realize a reduction in the size of the communication device.

  Next, FIG. 7 and FIG. 8 show comparison data of the insertion loss and attenuation amount of the bandpass filters BPFin and BPFout. FIG. 7 shows the attenuation characteristics of each bandpass filter. The gray part in the figure is a frequency band in which an unnecessary signal needs to be attenuated. Comparing the attenuation characteristics of BPFin and BPFout, BPFin is −23.8 dB and BPFout is −39.2 dB at 1.92 GHz on the low frequency side. Further, at 3.3 GHz on the high frequency side, BPFin is -17.6 dB and BPFout is -43.1 dB. In either band, BPFout takes a larger attenuation than BPFin. As a result, it is possible to secure an attenuation amount of an unnecessary signal that is insufficient with only BPFin by connecting BPFout to the output side. FIG. 8 shows insertion loss characteristics in the used frequency band. The gray part in the figure indicates the frequency band of the signal used for communication. Comparing the insertion loss characteristics of BPFin and BPFout, BPFout is −3.46 dB at 2.7 GHz where the insertion loss is the largest, whereas it is −1.38 dB for BPFin. By connecting a band-pass filter with a small insertion loss to the BPFin side, it is possible to minimize degradation of reception sensitivity.

  Next, with reference to FIGS. 9 to 11, the electrode pattern in the stacked body is shown in order from the upper surface, and the electrode related to the equivalent circuit will be described. In the S1 layer, which is a layer immediately below the top surface on which the components are mounted, the ground electrode GND is formed on almost the entire surface of the sheet. Thereby, interference with an internal electrode of a laminated body and an active element mounted on the upper surface of the laminated body can be prevented. In the S2 layer, band pass filters BPFin and BPFout and a part of electrodes constituting the balanced-unbalanced circuit BAL1 are arranged. Further, a through hole, which is the ground electrode GND, is disposed in a band shape between Cl1a and Cl2a and Cl3a and Cl4a. This is because the interference between Cl1a and Cl2a which are part of the BPFin circuit and Cl3a and Cl4a which are part of the BPFout circuit is suppressed as much as possible to improve isolation. As a result, the isolation between the input portion and the output portion of the low noise amplifier LNA can be increased, and oscillation of the low noise amplifier can be prevented.

  In the S3 layer, a part of the electrodes of the band pass filter is arranged, and a part of the electrodes constituting the high pass filter HPF1 is also arranged. In this layer, a band-like ground electrode is disposed between the high-pass filter and the band-pass filter BPFin and between the BPFin and BPFout to improve isolation between the paths. The strip electrode is preferably arranged for each layer or for each layer. Further, by adjusting the sizes of the electrodes Cl1b and Cl2b constituting a part of the bandpass filter BPFin and the electrodes Cl3b and Cl4b constituting a part of the bandpass filter BPFout, the matching of the bandpass filter can be adjusted.

  In the S4 layer, band pass filters BPFin and BPFout, a high pass filter HPF1, and a part of electrodes of the balanced-unbalanced circuit BAL1 are arranged. BPFin and BPFout are different in the manner of arrangement of capacitive electrodes, and BPFout is provided with cl5 which is a floating electrode. As a result, the capacitive coupling can be strengthened and the attenuation outside the communication band can be increased. Further, in three layers S2 to S4, electrodes for forming a capacitive component constituting a band-pass filter excluding the ground capacitance are arranged.

  In the S5 to S7 layers, a part of the electrodes constituting the high-pass filter HPF1 and the balanced-unbalanced circuit BAL1 are arranged. Further, when a capacitive component is newly required in the band-pass filter circuit, an electrode pattern may be provided in the layer.

  In the S8 to S10 layers, transmission lines constituting the resonators of the bandpass filters BPFin and BPFout are arranged. Transmission lines are arranged over three layers with both ends connected by through holes. This parallel line configuration can reduce the internal resistance of the transmission line and improve the insertion loss of the bandpass filter circuit. The resonance lines of each bandpass filter are formed on the same dielectric layer, and it is easy to match the characteristics of the bandpass filters of the two reception paths. In order to match the transmission lines, the distance between the transmission lines may be adjusted, the width of the transmission lines may be adjusted, or the length of the transmission lines may be adjusted. If necessary, a transmission line may be arranged across the S11 and S12 layers. The plurality of resonance lines of the first bandpass filter BPF1 (BPFin) and the plurality of resonance lines of the second bandpass filter BPF2 (BPFout) are respectively substantially linear. Further, the longitudinal direction of the plurality of resonance lines of the first bandpass filter BPF1 (BPFin) and the longitudinal direction of the plurality of resonance lines of the second bandpass filter BPF2 (BPFout) are the same. With this configuration, the bandpass filters can be densely arranged. In the embodiment shown in FIGS. 8 to 11, the longitudinal direction of the resonance line of the bandpass filter is the same for all bandpass filters, and even in a high-frequency component having five or more bandpass filters, the bandpass It is possible to arrange the filters densely, which contributes to miniaturization of high-frequency components. In addition, since the longitudinal directions of the bandpass filters are the same, when the electrodes are formed by printing, there is also an effect of suppressing characteristic fluctuation due to variations in the shape of the electrodes.

  Further, the resonance lines of the respective bandpass filters are all formed in the same dielectric layer, and this configuration can reduce the occupied portion of the entire bandpass filter in the stacking direction. Transmission path from switch circuit SW1 to transmission terminal P1 / P2 (TX1), reception path from switch circuit SW1 to reception terminal P3 / P4 (RX1), and reception path from switch circuit SW1 to reception terminal P5 / P6 (RX2) Are separated from each other when viewed in the longitudinal direction of the rectangular dielectric layer inside the laminate. The paths are juxtaposed via shield vias and shield electrodes connected to the ground. The longitudinal direction of the resonance line of each bandpass filter arranged in each path is the same as the juxtaposition direction of each path (longitudinal direction of the rectangular dielectric layer), and the bandpass filters between the paths interfere with each other. Is suppressed. Such a configuration can be widely applied to MIMO-type (including SIMO (Single Input Multi Output) -type) high-frequency components regardless of the configuration related to the filter characteristics between the bandpass filters.

  The S13 to S15 layers will be described. The S13 layer forms the ground electrode GND on almost the entire surface. As a result, interference with the grounded capacitance formed in the S14 layer can be prevented. In the S14 layer, an electrode serving as a ground capacitance of the bandpass filter is disposed. The ground electrode GND is formed on the entire surface of the S15 layer as well as the S13 layer. The three layers can form most of the ground capacitance of the bandpass filter circuit. The three-layer laminate sheet thickness is preferably thinner than the other layers. By using a thin sheet, a large capacity can be obtained with a small electrode area, and the high-frequency component can be miniaturized.

  In the above description, a part of the electrodes provided in the laminated body has been described. However, in this embodiment, the electrodes constituting the circuit from the antenna terminal ANT2 to the second receiving terminal RX2, and the antenna terminal ANT1 to the transmitting terminal TX are described. The electrodes constituting the above circuits are also arranged in the laminate. Similarly, in these circuits, a part of the inductance elements and capacitance elements constituting the band-pass filter circuit and the matching circuit are constituted by electrodes inside the laminate. Active elements such as a switch circuit and a power amplifier are mounted on the top surface of the laminate.

The high-frequency component according to the present invention is made of a ceramic dielectric material LTCC (Low Temperature Co-fired Ceramics) that can be sintered at a low temperature of 1000 ° C. or less, for example, and has a low resistivity on a green sheet having a thickness of 10 μm to 200 μm. It can be manufactured by printing a conductive paste such as Ag or Cu to form a predetermined electrode pattern, appropriately laminating a plurality of green sheets, and sintering. As the dielectric material, for example, Al, Si, Sr as a main component, Ti, Bi, Cu, Mn, Na, K as a minor component, Al, Si, Sr as a main component, Ca, Pb, A material containing Na and K as subcomponents, a material containing Al, Mg, Si, and Gd, and a material containing Al, Si, Zr, and Mg are used, and a material having a dielectric constant of about 5 to 15 may be used. . In addition to the ceramic dielectric material, it is also possible to use a resin material or a composite material obtained by mixing a resin and ceramic dielectric powder for the dielectric layer constituting the laminate of the high-frequency component. Moreover, you may produce the laminated body (ceramic laminated substrate) using the said ceramic dielectric material using the HTCC (high temperature simultaneous baking ceramic) technique. That is, the ceramic laminated substrate may be configured using a dielectric material mainly composed of Al ₂ O ₃ and a metal conductor that can be sintered at a high temperature such as tungsten or molybdenum. When a band-pass filter is configured with a ceramic multilayer substrate, pattern electrodes for inductance elements, capacitive elements, wiring, and ground electrodes are appropriately configured in each layer, and via conductors are formed between the layers. A desired circuit is configured.

  The high-frequency component according to the present invention is widely applicable not only to a high-frequency switch module but also to other high-frequency components. Further, the high-frequency component according to the present invention can be developed in various communication devices. Especially applicable to mobile phones, Bluetooth (registered trademark) communication devices, wireless LAN communication devices (802.11a / b / g / n), WiMAX (802.16e), IEEE802.20 (I-burst), etc. that handle high frequencies. It is possible. For example, in addition to a single-band communication device, a high-frequency front-end module that can share two communication systems of 2.4 GHz band wireless LAN (IEEE802.11b and / or IEEE802.11g) and 5 GHz band wireless LAN (IEEE802.11a) or A high-frequency front-end module capable of complying with the IEEE 802.11n standard is realized, and a small-sized multiband communication device including the same can be realized. The communication system is not limited to the frequency band and communication standard described above, and can be used for various communication systems. In addition to the two communication systems, for example, by adopting an aspect in which branching circuits are provided in more stages, it is possible to cope with a larger number of communication systems. Examples of multiband communication devices include wireless communication devices typified by mobile phones, personal computers (PCs), PC peripherals such as printers and hard disks, broadband routers, fax machines, refrigerators, standard televisions (SDTVs), and high-definition televisions. (HDTV), camera, video, and other electronic devices.

1 is an equivalent circuit diagram showing an embodiment of a high-frequency circuit according to the present invention. It is a characteristic view of the band pass filter used for the embodiment of the present invention. It is a figure which shows the characteristic difference by the difference in the form of a band pass filter. 1 is an equivalent circuit diagram showing an embodiment of a high-frequency circuit configured in a high-frequency component according to the present invention. It is a perspective view of one embodiment of a high frequency component concerning the present invention. FIG. 5 is an equivalent circuit diagram illustrating a part of the reception path of the high-frequency circuit illustrated in FIG. 4. It is a characteristic view of the band pass filter used for the embodiment of the present invention. It is a characteristic view of the band pass filter used for the embodiment of the present invention. It is a part of sheet | seat expansion | deployment figure for showing arrangement | positioning of the conductor pattern in the multilayer substrate of one Embodiment of the high frequency component which concerns on this invention. It is a part of sheet | seat expansion | deployment figure for showing arrangement | positioning of the conductor pattern in the multilayer substrate of one Embodiment of the high frequency component which concerns on this invention. It is a part of sheet | seat expansion | deployment figure for showing arrangement | positioning of the conductor pattern in the multilayer substrate of one Embodiment of the high frequency component which concerns on this invention.

Explanation of symbols

ANT1, ANT2: Antenna terminal BPF1-5: Band pass filter LNA1, LNA2: Low noise amplifier PA: Power amplifier HPF1, HPF2: High pass filter SW1, SW2: Switch circuit LPF: Low pass filter BAL1-3: Balance-unbalance circuit 1 : Front-end module 2: RFIC

Claims (5)

A low noise amplifier for amplifying a received signal of the first communication system;
A first band-pass filter connected to the input side of the low-noise amplifier with a frequency band of the first communication system as a pass band;
A high-frequency circuit including a second bandpass filter connected to the output side of the low-noise amplifier, with the frequency band of the first communication system as a passband,
In the frequency band of the first communication system, the insertion loss of the first bandpass filter is smaller than the insertion loss of the second bandpass filter,
The high-frequency circuit according to claim 1, wherein an attenuation amount of the second bandpass filter is larger than an attenuation amount of the first bandpass filter in at least a part of the stop band outside the passband. A high-frequency component comprising the high-frequency circuit according to claim 1 using a laminate formed by forming an electrode pattern on a plurality of dielectric layers, and an element mounted on the surface of the laminate,
The high-frequency component, wherein the first and second band pass filters are LC filters configured using an inductance element and a capacitance element formed in the multilayer body. The first and second bandpass filters are:
Each has a structure in which a plurality of resonant lines arranged in parallel in the laminate are electromagnetically coupled,
3. The high-frequency component according to claim 2, wherein the number of resonant lines of the second bandpass filter is equal to or greater than the number of resonant lines of the first bandpass filter. The plurality of resonance lines of the first band-pass filter and the plurality of resonance lines of the second band-pass filter are each substantially linear,
4. The high-frequency component according to claim 3, wherein the longitudinal direction of the plurality of resonance lines of the first band-pass filter is the same as the longitudinal direction of the plurality of resonance lines of the second band-pass filter.   The communication apparatus using the high frequency component in any one of Claims 2-4.

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