JP2005136888A - High frequency demultiplexer circuit, a high frequency component with the same packaged therein, high frequency module and radio communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a high frequency demultiplexer circuit low in loss and small in size by replacing a phase shift circuit PSC of the high frequency demultiplexer circuit with other small circuit. <P>SOLUTION: This circuit is provided with a low-pass filter and a high-pass filter HPF1 each including an inductance element and a capacitance element. The low-pass filter is configured by cascading a first low-pass filter circuit LPF1 with a ground capacitor C3 formed in one end of a notch circuit configured by parallel connecting a transmission line L1 comprising the inductance element and the capacitance element C1, and a second low-pass filter circuit LPF2 including the same configuration. An attenuation pole of one low-pass filter circuit is set to a frequency that is approximately the double of a pass frequency band of the low-pass filter, and an attenuation pole of the other low-pass filter is set to a frequency that is approximately (n) (n≥) times of the passing frequency band of the low-pass filter. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a high-frequency branching circuit, a high-frequency component, a high-frequency module, and a wireless communication device such as a mobile phone equipped with the high-frequency module.

In recent years, cellular phones have been widely used, and functions and services of cellular phones have been improved. In such a cellular phone, it is necessary to mount a high-frequency circuit necessary for the configuration of the transmission / reception system on the substrate.
On the other hand, a mobile phone adopting a multiband system in which two or more transmission / reception systems are mounted in one mobile phone has been proposed. A multi-band mobile phone is expected as a highly convenient device that uses a high-frequency branching circuit to select and transmit / receive a transmission / reception system suitable for regional characteristics and intended use.

For example, as a plurality of transmission / reception systems having different communication bands, a multi-function equipped with 2 to 4 transmission / reception systems of GSM850 system (850 MHz band) / GSM900 system (900 MHz band) and DCS system (1800 MHz band) / PCS system (1900 MHz band). Band-type mobile phones have been proposed.
As mobile phones become more multifunctional, smaller, and thinner, there is an increasing demand for low-loss, smaller, and thinner internal high-frequency components.

However, a multiband mobile phone has a large number of parts, and if a circuit is configured using individual dedicated parts, the size and cost of the equipment will increase. Therefore, it is required to advantageously develop the downsizing and cost reduction of the equipment by sharing the common circuit portion as much as possible.
FIG. 14 shows a circuit diagram of a high frequency demultiplexing circuit which is an example of a conventional high frequency component.

This high-frequency branching circuit is a circuit having a function of dividing a plurality of transmission / reception systems having different pass frequency bands into the respective transmission / reception systems. In FIG. 14, P1 is a terminal connected to the antenna, P2 is an input / output terminal in the 800 to 900 MHz band (hereinafter referred to as “low frequency band”), and P3 is in the 1800 to 1900 MHz band (hereinafter referred to as “high frequency side”). Input / output terminal.
The circuit configuration between the terminals P1 and P2 is cascaded from the P1 side in the order of the phase shift circuit PSC and the low-pass filter LPF3.

The phase shift circuit PSC is composed of a phase shift line L4 and a phase shift grounding capacitor C8. The phase shift line L4 uses a transmission line such as a strip line.
The LPF 3 includes a transmission line L5 and capacitance elements C9 and C10 that constitute an inductance element.
A high-pass filter HPF2 is connected between the terminals P1 and P3. The HPF 2 includes capacitance elements C11, C12, and C13 and a transmission line L6 that forms an inductance element.

If only LPF3 and HPF2 are connected, impedance mismatching occurs at both the pass band and the stop band at terminal P1, and it does not function as a high-frequency branching circuit. Therefore, a phase shift circuit PSC is inserted between LPF 3 and P1, and low-pass By matching the phase of the blocking region of the filter LPF3 to the open state, the matching state at the terminal P1 is ensured satisfactorily.
FIG. 15 shows the phase characteristics of only the LPF 3 viewed from the P1 side, FIG. 16 shows the phase characteristics viewed from the P1 side when the phase shift circuit PSC is inserted in the previous stage of the LPF 3, and FIG. 17 viewed from the P1 side. The phase characteristic of HPF2 is shown. The black triangle represents the low frequency band, and the black circle represents the high frequency band. In the case of FIGS. 15 and 16, the black triangle is the pass band and the black circle is the stop band, and in the case of FIG.

In FIG. 15, the impedance of the stop band is deviated from the open state (resistance infinite), but in FIG. 16, it can be seen that the stop band can be arranged at a position close to the open state by the phase shift circuit PSC.
Further, when the thickness of the dielectric substrate of the high-frequency branching circuit is thin, the impedance of the phase shift line L4 becomes low and the passband consistency deteriorates. ing.

FIG. 18 is a graph showing the transmission characteristics of this high-frequency branching circuit. In FIG. 18, the solid line shows the transmission characteristic of the low-pass filter LPF3 in which the phase shift circuit PSC is inserted, and the broken line shows the transmission characteristic of the high-pass filter HPF2.
Japanese Patent Laid-Open No. 11-225088 JP 2001-285112 A

  In the conventional circuit of FIG. 14, it is necessary to increase the inductance of the phase shift line L4 of the phase shift circuit PSC for matching the LPF 3 and the HPF 2, and the length thereof is long. In addition, the capacitance of the capacitance element C8 needs to be increased, and the area thereof is increased. Since the line length of the phase shift line L4 is long, the insertion loss of the high-frequency branching circuit is increased and the occupied area is also increased, so that it is difficult to reduce the loss and reduce the size. Further, since the area of the capacitance element C8 is large, it is difficult to reduce the size.

For this reason, in the above configuration, the phase shift circuit PSC is a serious problem when it meets the demand for low loss and downsizing.
The present invention has been made in order to solve the above-described problems. By changing the circuit configuration of the high-frequency branching circuit from the prior art and replacing the phase shift circuit PSC with another small circuit, low loss and downsizing can be achieved. An object of the present invention is to provide a high-frequency demultiplexing circuit to be realized, and a high-frequency component, a high-frequency module, and a wireless communication device on which the high-frequency demultiplexing circuit is mounted.

  The high-frequency branching circuit of the present invention includes a low-frequency band filter and a high-frequency band filter including an inductance element and a capacitance element, and the low-frequency band filter includes a transmission line and a capacitance element constituting the inductance element. A first low-pass filter circuit in which a ground-to-ground capacitance is formed at one end of a notch circuit connected in parallel and a second low-pass filter circuit having the same configuration are connected in cascade, Of the first and second low-pass filter circuits, the attenuation pole of one low-pass filter circuit is arranged on the higher frequency side than the pass frequency band of the low-frequency band filter, and the other low-pass filter circuit The attenuation pole of the pass filter is arranged at a frequency about n times (n ≧ 3) the pass frequency band of the low frequency band filter.

  In this way, the low-frequency band filter is constituted by a two-stage connection filter including an inductance element and a capacitance element, and by adjusting the attenuation poles thereof, the low-pass filter can be obtained without the phase shift circuit PSC. And the high-pass filter can be matched. Further, since the phase shift circuit PSC can be eliminated, the area can be reduced by about 40%, the insertion loss can be improved by 0.3 dB, and a small high-frequency component can be manufactured with low loss.

In the high frequency band filter, at least two capacitance elements are connected in series, a transmission line constituting an inductance element having one end grounded is connected to a connection point of the at least two capacitance elements, and the series connected capacitances are connected. A device in which a capacitance element is further connected to both ends of the element can be used.
The high-frequency component of the present invention is obtained by forming the high-frequency branching circuit on the surface and / or inside of a dielectric multilayer substrate in which a plurality of dielectric layers are laminated.

In this high-frequency component, it is preferable that a notch circuit, which is a component of one of the low-pass filters, is formed on an upper portion of a region having no ground electrode on the back surface of the dielectric multilayer substrate. As a result, unnecessary parasitic capacitance between the notch circuit and the ground can be reduced, so that the low-pass frequency characteristics can be kept good.
Further, it is preferable that the other low-pass filter is disposed on an upper portion of a grounding counter electrode that forms an inter-ground capacitance that is a component of the one low-pass filter. As a result, unnecessary parasitic capacitance generated between the notch circuit of the other low-pass filter and the ground can be reduced, so that the low-pass frequency characteristic can be kept good.

In the high frequency module of the present invention, the high frequency demultiplexing circuit is formed on the surface and / or inside of a dielectric multilayer substrate formed by laminating a plurality of dielectric layers, and a high frequency switch circuit, a high frequency power amplifier circuit, a surface acoustic wave is formed. At least one of a filter, an FBAR filter, and a duplexer is mounted on the surface of the dielectric multilayer substrate.
In addition, the wireless communication device of the present invention can reduce the size of the wireless communication device and improve the communication performance by mounting the high-frequency module.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram showing a configuration example of a high-frequency circuit including a high-frequency branching circuit DIP10 according to the present invention. The high-frequency circuit handles a transmission / reception system having different four pass frequency bands of the GSM850 system (850 MHz band), the GSM900 system (900 MHz band), the DCS system (1800 MHz band), and the PCS system (1900 MHz band).

  The high-frequency circuit is connected to one common antenna terminal P1, the high-frequency demultiplexing circuit DIP10 that is connected to the antenna terminal P1, and divides a plurality of transmission / reception systems into two systems GSM850 / GSM900 and DCS / PCS, and each transmission / reception system GSM850 / GSM900. And DCS / PCS are connected to high-frequency switches SW110 and SW120 that switch between a reception signal input from the antenna and a transmission signal that feeds the antenna, a decoder DEC10 that controls the state of the high-frequency switch, and high-frequency switches SW110 and SW120, respectively. And low pass filters LPF30 and LPF40 for attenuating harmonic components of transmission signals of the transmission systems of GSM850 / GSM900 and DCS / PCS.

The radio signal that has entered from the antenna is input to the high-frequency demultiplexing circuit DIP10, where a received signal in a specific frequency band is selectively passed. The received signal passes through the high frequency switches SW110 and SW120, is amplified by a low noise amplifier (not shown), and is supplied to a received signal processing circuit (not shown).
On the other hand, the transmission signal is subjected to noise reduction through a high frequency filter (not shown) that allows transmission signals in a predetermined frequency band to pass through, and is supplied to a high frequency power amplifier circuit (not shown). The high frequency power amplifier circuit amplifies the transmission signal and supplies the amplified signal to the high frequency branching circuit DIP10 via the low pass filters LPF30 and LPF40 and the high frequency switches SW110 and SW120.

FIG. 2 is a circuit diagram of the high frequency demultiplexing circuit DIP10 shown in FIG. The high-frequency branching circuit DIP10 is connected to the antenna via the terminal P1, and is connected to the high-frequency switches SW110 and SW120 via the terminals P2 and P3.
The GSM850 / GSM900 reception signal received from the antenna terminal P1 is guided to the GSM850 / GSM900 transmission / reception system via the terminal P2, and the DCS / PCS reception signal is transmitted to the DCS / PCS side transmission / reception system via the terminal P3. Led to.

First, the circuit on the GSM850 / GSM900 side will be described. The high-frequency branching circuit DIP10 includes two low-pass filters LPF1 and LPF2 connected in series.
The low-pass filter LPF1 includes a transmission line L1 constituting an inductance element, a capacitance element C1 arranged in parallel to the transmission line L1, and a capacitance element C3 formed between the distributed constant line L1 and the ground. Has been.

The low-pass filter LPF2 includes a transmission line L2 constituting an inductance element, a capacitance element C2 arranged in parallel to the transmission line L2, and a capacitance element C4 formed between the distributed constant line L1 and the ground. ing. The low-pass filters LPF1 and LPF2 have the same basic circuit configuration but different element values.
These low-pass filters LPF1 and LPF2 reduce harmonic components of the transmission signal input via the terminal P2, and receive signals in the frequency band of the transmission / reception system GSM850 / GSM900 from the reception signals of the antenna terminal P1. It has a function to select.

  Next, the DCS / PCS side circuit is composed of a high-pass filter HPF1. The HPF 1 includes capacitance elements C5 and C6 connected in series, a transmission line L3 formed between these capacitors and the ground, and a capacitance element C7 connected in parallel to the capacitance elements C5 and C6. ing. The high-pass filter HPF1 attenuates the low-frequency component of the transmission signal input via the terminal P3, and receives a frequency band on the transmission / reception system DCS / PCS side from the reception signal input from the antenna terminal P1. It has a function to select and pass signals. Further, the high-pass filter HPF1 has a function of protecting the high-frequency switch SW120 from a surge such as ESD input to the ANT terminal P1.

In the example of the present invention, the attenuation pole of LPF1 is arranged about three times the fundamental frequency of the low frequency band, and the attenuation pole of LPF2 is arranged in the stop band, that is, the high frequency band.
3 shows the phase characteristics of LPF1 alone viewed from the P1 side, FIG. 4 shows the phase characteristics of LPF2 alone viewed from the P1 side, and FIG. 5 shows from the P1 side when LPF1 and LPF2 are connected in cascade (LPF1 + LPF2). The phase characteristics of the viewed LPF1 + LPF2 are shown. FIG. 6 shows the phase characteristics of HPF 1 viewed from the P1 side.

The black triangle represents the low frequency band, and the black circle represents the high frequency band. In the case of FIGS. 3 to 5, the black triangle is the pass band and the black circle is the stop band, and the reverse is the case in FIG.
In FIG. 4, the impedance of the stop band of LPF2 deviates from the open state, but from FIG. 5, the combined impedance of LPF1 + LPF2 is a matched state in the low-frequency band signal pass band and the stop band is close to the open state. It can be seen that they are arranged.

In order to achieve such a state, it is necessary to adjust the values of the inductor elements and the capacitance elements that constitute LPF1 and LPF2 so that the combined impedance of LPF1 + LPF2 has a desired phase characteristic.
It is easy to match the low frequency band signal, that is, the pass band, because both LPF 1 and LPF 2 are in the vicinity of the pass band (see FIGS. 3 and 4).

  In order to make the stop band close to the open state, it is necessary to adjust the balance of LPF1 and LPF2. Specifically, the impedance of LPF1 in the stop band is made inductive, and the impedance of LPF2 in the stop band is made capacitive. Thereafter, the capacitance elements and the inductance elements constituting the LPF 1 and LPF 2 are finely adjusted to a desired combined impedance.

In the present invention, the low-pass filter LPF1 + LPF2 is realized as a means for making the stop band of the low-pass filter LPF1 + LPF2 inductive by using a low-pass filter LPF1 + LPF2 whose attenuation pole is arranged about three times the fundamental wave of the low frequency band.
FIG. 7 is a graph showing the transmission characteristics of the low-pass filter LPF1 + LPF2. In FIG. 7, the solid line indicates the transmission characteristic of the low-pass filter LPF1 + LPF2, and the broken line indicates the transmission characteristic of the high-pass filter HPF1.

  Compared with the transmission characteristic (solid line) of the conventional low-pass filter LPF3 of FIG. 18, the conventional low-pass filter PSC + LPF3 has a frequency twice the fundamental frequency (about 800 MHz) in the GSM850 / GSM900 band, that is, DCS / While the attenuation pole is formed at the frequency of the PCS band (about 1.6 GHz), the low-pass filter LPF1 + LPF2 of the present invention has frequencies twice and three times the fundamental wave (1.6 GHz and 2.6 GHz). ) Shows that an attenuation pole is formed.

The low-pass filters LPF1 and LPF2 connected in two stages can reduce the conventional large-capacity phase shift circuit PSC and replace it with a small LPF1, so that the occupied area can be reduced by about 40%, and the high-frequency circuit Can be miniaturized.
In addition, since the line loss of the large phase shift circuit PSC can be reduced, a high frequency circuit with improved insertion loss of about 0.3 dB can be manufactured. At the same time, it is easy to suppress the third harmonic.

FIG. 8 is a diagram showing a pattern when the high-frequency branching circuit of the present invention is formed in a dielectric multilayer substrate.
The dielectric multilayer substrate 11 is formed by sequentially laminating first to ninth dielectric layers 101 to 109 from above. Capacitor electrodes C101 to C110 that form capacitance elements are formed on the top surfaces of the third to eighth dielectric layers 103 to 108. In addition, transmission line conductor patterns L101 to L111 constituting inductance elements are formed on the top surfaces of the second to seventh dielectric layers 102 to 107, respectively. Further, a ground electrode pattern G101 is formed on the upper surface of the first dielectric layer 101, and a ground electrode pattern G102 is formed on the lower surface of the ninth dielectric 109. The four corners of both are electrically connected by through vias VIA101 to 104. Connected.

  On the lower surface of the ninth dielectric 109, electrode terminals T101, T102, and T103 to be the first to third terminals P1 to P3 are formed. The capacitor electrode C110 and the electrode terminal T101, the capacitance element C1, the capacitor electrode C109 and the ground electrode G102, the capacitance element C3, the capacitor electrodes C101, C103, C105, C107, and C108, the capacitance element C2, and the capacitor electrode C101 and the ground electrode. G101 forms a capacitance element C4, capacitor electrodes C102 and C104 form a capacitance element C5, capacitor electrodes C104 and C106 form a capacitance element C6, and capacitor electrodes C102 and C106 form a capacitance element C7.

The capacitor electrodes C101, C105, and C108 are electrically connected by through vias VIA111, and the capacitor electrodes C103 and C107 are electrically connected by through vias VIA112.
Further, the transmission line conductor patterns L101, L102, L104, L106, and L109 are electrically connected through the through vias VIA105, VIA106, VIA107, and VIA108 to form the transmission line L1. The transmission line conductor patterns L103, L107, and L111 are electrically connected via through vias VIA113 and VIA114 to form the transmission line L2. The transmission line conductor patterns L105, L108, and L110 are electrically connected through the through vias VIA117 and VIA118, and then electrically connected to the ground electrode G102 through the through vias VIA119, thereby forming the transmission line L3. .

  Further, the electrode terminal T101 and the conductor pattern L109 of the transmission line are electrically connected through the through via VIA 109, and the electrode terminal T103 is electrically connected through the capacitor electrode C102 and the through via VIA115. LPF1 and LPF2 have transmission line conductor patterns L101 and L111 connected by through vias VIA110, and terminals P1 and HPF1 branch from through vias VIA109 connected to external terminals T101 to transmission lines 112 and through through vias VIA116. Connected. The LPF 2 and the terminal P2 are connected by electrically connecting the transmission line 111 connected to the through via VIA 111 and the electrode terminal T102 via the through via VIA 120.

  FIG. 9 is a diagram in which only a partial area A of the dielectric layers 101 to 109 is surrounded by a broken line. This region A shows a region in which the ground electrode G102 is cut out to form the external terminal T101, and the conductor patterns L101, L102, L104, L106, L109 and the capacitor electrode C110 forming the transmission line L1 are in this region A. It is contained in. As described above, since the ground electrode G102 is not provided in the portion where the notch circuit constituting the low-pass filter LPF1 is formed, unnecessary parasitic capacitance between the ground electrode G102 and the ground electrode G102 can be reduced. Can be kept.

  A region B in FIG. 10 shows a region where the capacitor electrode C109 is formed. The conductor patterns L103, L107, and L111 and the capacitor electrodes C101, C103, C105, C107, and C108 that form the transmission line L2 are included in the region B. It is stored. That is, the low-pass filter LPF2 is arranged on the capacitor C3 that forms the capacitance between the ground formed by the ground electrode G102 and the capacitor electrode C109. Thus, the capacitor electrode C109 serves as a shield that reduces unnecessary ground-to-ground parasitic capacitance that can occur between the conductor patterns L103, L107, and L111 of the transmission line and the capacitor electrodes C101, C103, C105, C107, and C108 and the ground electrode G102. Therefore, the electrical characteristics can be kept good.

The high frequency demultiplexing circuit of the present invention is used by being incorporated in a chip demultiplexer having a demultiplexing function or a high frequency module.
FIG. 11 is a perspective view of the duplexer 10 including the high-frequency branching circuit according to the present invention. 8 to 10 is configured in a dielectric multilayer substrate in which a plurality of dielectric layers of the same size and shape made of ceramic or the like are laminated. In the case of such a chip-like component, the electrode terminals in FIG. 8 are provided at symmetrical positions. In FIG. 11, a plurality of electrode terminals 12 are provided on the side surface of the dielectric multilayer substrate.

FIG. 12 is a cross-sectional view schematically showing conductor patterns 52 and 53 such as distributed constant lines, coupled lines, distributed capacitors, resistors, etc., which are internal elements formed in each dielectric layer of the dielectric multilayer substrate 11. FIG. Reference numeral 54 denotes a via-hole conductor necessary for vertically connecting the circuits across each dielectric layer.
FIG. 13 is a perspective view showing a high-frequency module 13 incorporating the high-frequency branching circuit of the present invention. The high-frequency module 13 forms a high-frequency branching circuit inside the dielectric multilayer substrate 11, and a semiconductor integrated circuit element 82, a surface acoustic wave filter, and an FBAR filter constituting a high-frequency power amplifier circuit on the top surface of the dielectric multilayer substrate 11. A device 83 such as a duplexer, a semiconductor integrated circuit device 84 constituting the high-frequency switch SW100, and the like are mounted. In addition, in the dielectric multilayer substrate 11, in addition to the duplexer 10, the low-pass filters LPF30 and LPF40, a directional coupler for monitoring transmission power, and the output impedance of the high-frequency power amplifier circuit are characteristic impedances. An output matching circuit or the like for matching is formed. Reference numeral 85 denotes an external connection terminal formed on the bottom surface of the dielectric multilayer substrate 11. The high-frequency module 13 is preferably mounted on a wireless communication device that is required to be small and light, such as a mobile phone or PDF, and is mounted and mounted on the surface of the motherboard substrate.

The dielectric layer in the duplexer 10 or the high frequency module 13 is formed by forming a conductor pattern with a conductor such as copper foil on an organic dielectric substrate such as glass epoxy resin, and laminating and thermosetting the conductive layer. Or various conductor patterns formed on an inorganic dielectric layer such as a ceramic material, and these are laminated and fired at the same time.
In particular, if a ceramic material is used, the dielectric constant of the ceramic dielectric is usually 9 to 25, which is higher than that of the resin substrate. Therefore, the dielectric layer can be made thinner, and the size of the circuit element embedded in the dielectric layer can be reduced. The distance between the elements can be reduced, and the distance between the elements can also be reduced.

In particular, it is desirable to use a ceramic material that can be fired at a low temperature, such as glass ceramics, because the conductor pattern can be formed of low resistance copper, silver, or the like. The via-hole conductor is formed by plating a through hole formed in the dielectric layer or filling a conductor paste.
Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments. For example, in the above-described embodiment, the attenuation pole of the LPF 1 is adjusted to about three times the fundamental wave of the low frequency band. However, even if the attenuation pole is adjusted to be arranged about n times the fundamental wave (n ≧ 3). Good. In the above embodiment, a multi-band mobile phone equipped with 2 to 4 transmission / reception systems of GSM850 system (850 MHz band) / GSM900 system (900 MHz band) and DCS system (1800 MHz band) / PCS system (1900 MHz band) is shown. However, it may be a multiband mobile phone equipped with two CDMA 800 MHz band and 1900 MHz band transmission / reception systems, or a multiband mobile phone combining a GSM system and a CDMA system. In addition, various modifications can be made within the scope of the present invention.

It is a block diagram which shows the circuit structural example of the high frequency branching circuit DIP10 which concerns on this invention. FIG. 2 is a circuit diagram of a high frequency branching circuit DIP10 shown in FIG. It is a Smith chart which shows the phase characteristic of LPF1 independent seen from P1 side. It is a Smith chart which shows the phase characteristic of LPF2 independent seen from P1 side. 6 is a Smith chart showing the phase characteristics of LPF1 + LPF2 viewed from the P1 side when LPF1 and LPF2 are connected in cascade (LPF1 + LPF2). It is a Smith chart which shows the phase characteristic of HPF1 seen from the P1 side. It is a graph which shows the transmission characteristic of low-pass filter LPF1 + LPF2. It is a figure which shows the pattern at the time of forming the high frequency branching circuit of this invention in a dielectric multilayer substrate. It is the figure which surrounded only the partial area | region A of the dielectric material layers 101-109 with the broken line. It is the figure which surrounded only the partial area | region B of the dielectric material layers 101-109 with the broken line. 1 is a perspective view of a duplexer 10 equipped with a high frequency branching circuit according to the present invention. 3 is a cross-sectional view schematically showing conductor patterns 52 and 53 such as distributed constant lines, coupled lines, distributed capacitors, resistors, etc., which are internal elements, formed in each dielectric layer of the dielectric multilayer substrate 11. FIG. It is a perspective view which shows the high frequency module 13 incorporating the high frequency branching circuit of this invention. The circuit diagram of the conventional high frequency branching circuit is shown. It is a Smith chart which shows the phase characteristic which looked at only LPF3 in the conventional high frequency branching circuit from the P1 side. It is a Smith chart which shows the phase characteristic seen from the P1 side at the time of inserting the phase shift circuit PSC in the front | former stage of LPF3 in the conventional high frequency branching circuit. It is a Smith chart which shows the phase characteristic which looked at HPF2 in the conventional high frequency branching circuit from the P1 side. It is a graph which shows the transmission characteristic of the conventional high frequency branching circuit.

Explanation of symbols

10 Demultiplexer 11 Dielectric multilayer substrate 12 External connection terminal 13 High frequency module 52 Conductor pattern 53 constituting inductance element Conductor pattern 54 constituting capacitance element Via-hole conductors 82 and 84 Semiconductor integrated circuit element 83 Surface acoustic wave filter 85 External connection Terminals 101-109 Dielectric layers 111, 112 Transmission lines C1-C7, C9-C13 Capacitance element C8 Phase-shifting ground capacitances C101-C110 Capacitor electrode DIP10 High-frequency branching circuit G101, G102 Ground electrode HPF High-pass filters L1-L3 , L5, L6 Inductance element L4 Phase shift line L101-L111 Transmission line LPF Low pass filter P1-P3 Terminal PSC Phase shift circuit SW110, SW120 High frequency switch circuit T101-T103 External terminal VIA10 ~VIA120 through vias

Claims (8)

In a high frequency demultiplexing circuit having a function of dividing a plurality of transmission / reception systems having different pass frequency bands into each transmission / reception system
A low frequency band filter including an inductance element and a capacitance element, and a high frequency band filter,
The filter for the low frequency band has the same configuration as the first low-pass filter circuit in which a capacitance between the grounds is formed at one end of a notch circuit formed by connecting a transmission line and a capacitance element forming an inductance element in parallel. A second low-pass filter circuit having a cascade connection;
Of the first and second low-pass filter circuits, the attenuation pole of one low-pass filter circuit is arranged on the higher frequency side than the pass frequency band of the low-frequency band filter, and the other low-pass filter circuit A high-frequency branching circuit characterized in that the attenuation pole of the pass filter is arranged at a frequency about n times (n ≧ 3) the pass frequency band of the low-frequency band filter.   The high-frequency branching circuit according to claim 1, wherein the attenuation pole of the one low-pass filter circuit is provided in a pass frequency band of a filter for a high-frequency band.   In the high frequency band filter, at least two capacitance elements are connected in series, a transmission line constituting an inductance element having one end grounded is connected to a connection point of the at least two capacitance elements, and the series connected capacitances are connected. The high-frequency branching circuit according to claim 1 or 2, wherein a capacitance element is further connected to both ends of the element. A high-frequency component equipped with the high-frequency branching circuit according to any one of claims 1 to 3,
A high-frequency component formed by forming the high-frequency branching circuit on and / or inside a dielectric multilayer substrate formed by laminating a plurality of dielectric layers.   5. The high-frequency component according to claim 4, wherein a notch circuit, which is a constituent element of one of the low-pass filters, is formed on an upper portion of a region having no ground electrode on the back surface of the dielectric multilayer substrate.   6. The high-frequency component according to claim 5, wherein the other low-pass filter is disposed on an upper part of a grounding counter electrode that forms a capacitance between the grounds that is a component of the one low-pass filter.   The high frequency branching circuit according to any one of claims 1 to 3 is formed on a surface and / or inside of a dielectric multilayer substrate in which a plurality of dielectric layers are laminated, and a high frequency switch circuit, a high frequency power amplification A high frequency module comprising at least one of a circuit, a surface acoustic wave filter, an FBAR filter, and a duplexer mounted on a surface of the dielectric multilayer substrate. A wireless communication device on which the high-frequency module according to claim 7 is mounted.

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