U.S. patent application number 14/455696 was filed with the patent office on 2014-11-27 for high-frequency circuit module.
This patent application is currently assigned to TAIYO YUDEN CO., LTD.. The applicant listed for this patent is TAIYO YUDEN CO., LTD.. Invention is credited to Hiroshi Nakamura, Tetsuo Saji.
Application Number | 20140349596 14/455696 |
Document ID | / |
Family ID | 47789903 |
Filed Date | 2014-11-27 |
United States Patent
Application |
20140349596 |
Kind Code |
A1 |
Saji; Tetsuo ; et
al. |
November 27, 2014 |
HIGH-FREQUENCY CIRCUIT MODULE
Abstract
Provided is a high-frequency module that can prevent a
transmission signal from reaching a reception circuit and that can
achieve high mounting density. A first duplexer for a first
frequency band is mounted on a circuit substrate, and a second
transmission filter and a second reception filter that constitute a
second duplexer for a second frequency band are embedded in the
circuit substrate. The second transmission filter and the second
reception filter are embedded in the circuit substrate in locations
that overlap at least a part of a projection region that is formed
by projecting the first duplexer in a thickness direction of the
circuit substrate. The first frequency band and the second
frequency band are separated from each other by at least a
prescribed frequency range.
Inventors: |
Saji; Tetsuo; (Tokyo,
JP) ; Nakamura; Hiroshi; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TAIYO YUDEN CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
TAIYO YUDEN CO., LTD.
Tokyo
JP
|
Family ID: |
47789903 |
Appl. No.: |
14/455696 |
Filed: |
August 8, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13966517 |
Aug 14, 2013 |
8838059 |
|
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14455696 |
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Current U.S.
Class: |
455/78 |
Current CPC
Class: |
H04B 1/006 20130101;
H04B 1/525 20130101; H04B 1/40 20130101; H04B 15/00 20130101 |
Class at
Publication: |
455/78 |
International
Class: |
H04B 1/40 20060101
H04B001/40; H04B 15/00 20060101 H04B015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 16, 2012 |
JP |
2012-180527 |
Claims
1. A high-frequency circuit module, comprising: a circuit substrate
that is provided with a transmission circuit and a reception
circuit for a high-frequency signal; a first transmission filter
that filters a signal in a first frequency band outputted from the
transmission circuit and a first reception filter that filters a
signal in the first frequency band inputted into the reception
circuit; and a second transmission filter that filters a signal in
a second frequency band outputted from the transmission circuit and
a second reception filter that filters a signal in the second
frequency band inputted into the reception circuit, wherein the
first frequency band and the second frequency band are separated
from each other by at least a prescribed frequency range
therebetween, wherein the first transmission filter and the first
reception filter are mounted on the circuit substrate, and wherein
the second transmission filter and the second reception filter are
embedded in the circuit substrate so as to overlap at least a part
of the first transmission filter and the first reception filter
when viewed in a plan view.
2. The high-frequency circuit module according to claim 1, wherein
the circuit substrate is provided with a ground conductive layer
that is formed between the first transmission filter and the second
reception filter and between the second transmission filter and the
first reception filter.
3. The high-frequency circuit module according to claim 1, wherein
the first transmission filter and the first reception filter
constitute a first duplexer circuit, and wherein the second
transmission filter and the second reception filter constitute a
second duplexer circuit.
4. The high-frequency circuit module according to claim 3, wherein
the first duplexer circuit is enclosed in a package, and the
package is mounted on the circuit substrate, and the second
transmission filter and the second reception filter are embedded in
the circuit substrate as separate components, respectively.
5. The high-frequency circuit module according to claim 1, further
comprising a third transmission filter that filters a signal in a
third frequency band outputted from the transmission circuit and a
third reception filter that filters a signal in a third frequency
band inputted into the reception circuit, wherein the first
frequency band and the third frequency band partially overlap, or
are close to each other, and wherein the third transmission filter
and the third reception filter are mounted on the circuit substrate
so as to be at least a prescribed distance away from the first
transmission filter and the first reception filter.
6. The high-frequency circuit module according to claim 5, wherein
the third transmission filter and the third reception filter
constitute a third duplexer circuit.
7. The high-frequency circuit module according to claim 6, wherein
the third duplexer circuit is enclosed in a package, and the
package is mounted on the circuit substrate.
8. A high-frequency circuit module, comprising: a circuit substrate
that is provided with a transmission circuit and a reception
circuit for a high-frequency signal; a first transmission filter
that filters a signal in a first frequency band outputted from the
transmission circuit and a first reception filter that filters a
signal in the first frequency band inputted into the reception
circuit; a second transmission filter that filters a signal in a
second frequency band outputted from the transmission circuit and a
second reception filter that filters a signal in the second
frequency band inputted into the reception circuit; and a fourth
transmission filter that filters a signal in a fourth frequency
band outputted from the transmission circuit and a fourth reception
filter that filters a signal in the fourth frequency band inputted
into the reception circuit, wherein the first frequency band and
the second frequency band are separated from each other by at least
a prescribed frequency range therebetween, wherein the first
transmission filter and the first reception filter are mounted on
the circuit substrate, and wherein the second transmission filter
and the second reception filter are embedded in the circuit
substrate so as to overlap at least a part of the first
transmission filter and the first reception filter when viewed in a
plan view, wherein the second frequency band and the fourth
frequency band partially overlap, or are close to each other, and
wherein the fourth transmission filter and the fourth reception
filter are embedded in the circuit substrate so as to be at least a
prescribed distance away from the second transmission filter and
the second reception filter.
9. The high-frequency circuit module according to claim 8, wherein
the fourth transmission filter and the fourth reception filter
constitute a fourth duplexer circuit.
10. The high-frequency circuit module according to claim 9, wherein
the fourth transmission filter and the fourth reception filter are
embedded in the circuit substrate as separate components,
respectively.
Description
[0001] This application claims the benefit of Japanese Application
No. 2012-180527, filed in Japan on Aug. 16, 2012, which is hereby
incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to a high-frequency circuit
module having a high-frequency circuit mounted on a circuit
substrate thereof, and more particularly, to a mounting structure
of a transmission filter that filters a high-frequency signal
outputted from a transmission circuit and a reception filter that
filters a high-frequency signal inputted into a reception
circuit.
BACKGROUND ART
[0003] In recent years, mobile phones are becoming more
sophisticated and smaller as represented by multi-function mobile
phones, i.e., smart phones. In such mobile phones, a high-frequency
circuit module, in which various components that are necessary for
transmitting and receiving high-frequency signals are mounted on a
circuit substrate thereof, is provided on a mother board (see
Patent Document 1, for example). In the high-frequency circuit
module described in Patent Document 1, a power amplifier IC, a
transmission filter, a reception filter, and the like are provided
on the circuit substrate. Inside the circuit substrate, passive
components such as capacitors that constitute a matching circuit
and the like are embedded. The high-frequency circuit module
described in Patent Document 1 is provided with two
transmission/reception systems respectively for the cellular system
800 MHz band and for the PCS (Personal Communication Services)
system 1.9 GHz band, and one reception system for the 1.5 GHz band
that is the reception band of GPS (Global Positioning System) so as
to enable the positioning function that utilizes GPS.
RELATED ART DOCUMENTS
Patent Documents
[0004] Patent Document 1: Japanese Patent Application Laid-Open
Publication No. 2005-277939
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0005] The high-frequency circuit module described in Patent
Document 1 is equipped with the transmission/reception systems for
the two frequency bands as described above, but in recent years,
there have been demands for a capability of handling a greater
number of frequency bands and further size reduction. However, the
configuration described in Patent Document 1 did not allow a
plurality of transmission/reception systems for various frequency
bands to be mounted in high density. The transmission filter and
the reception filter, in particular, cause a problem because they
require relatively large mounting areas, and they are likely to
cause a transmission signal to interfere with the reception
circuit. The latter is a phenomenon that occurs when a
high-frequency signal that has been transmitted through the first
transmission/reception system enters the reception circuit through
the second transmission/reception system. This phenomenon is caused
as a result of the frequency bands of a plurality of
transmission/reception systems partially overlapping or being close
to each other. The following case can be given as a specific
example: let's assume that the transmission band in the frequency
range of the first transmission/reception system overlaps the
reception band in the frequency range of the second
transmission/reception system, and a duplexer of the first
transmission/reception system and a duplexer of the second
transmission/reception system are mounted on a circuit substrate
adjacently to each other. In this case, when the communication is
performed using the first transmission/reception system, the
transmission signal is directly coupled with the reception filter
of the duplexer of the second transmission/reception system through
the electromagnetic coupling, or is electromagnetically coupled
with antenna wiring. This causes the transmission signal to flow
into the reception filter of the duplexer of the second
transmission/reception system, and subsequently flow into the
reception circuit through the reception filter. In recent mounting
techniques, the reception circuits of the first
transmission/reception system and the second transmission/reception
system are often included in a common integrated circuit.
Therefore, in a vicinity of the integrated circuit, the
transmission signal that has passed through the reception filter of
the duplexer and that flows through the reception wiring of the
second transmission/reception system may be electromagnetically
coupled with wiring of the first transmission/reception system, and
may flow into the reception circuit of the first
transmission/reception system of the integrated circuit.
[0006] The present invention was made in view of the
above-mentioned problems, and aims at providing a high-frequency
circuit module that can prevent the loop interference of the
transmission signal with the reception circuit and that can achieve
high mounting density.
Means for Solving the Problems
[0007] In order to achieve the above object, a high-frequency
circuit module according to the present invention includes: a
circuit substrate provided with a transmission circuit and a
reception circuit for a high-frequency signal; a first transmission
filter that filters a signal in a first frequency band outputted
from the transmission circuit and a first reception filter that
filters a signal in the first frequency band inputted into the
reception circuit; and a second transmission filter that filters a
signal in a second frequency band outputted from the transmission
circuit and a second reception filter that filters a signal in the
second frequency band inputted into the reception circuit, wherein
the first frequency band and the second frequency band are
separated from each other by at least a prescribed frequency range
therebetween, wherein the first transmission filter and the first
reception filter are mounted on the circuit substrate, and wherein
the second transmission filter and the second reception filter are
embedded in the circuit substrate so as to overlap at least a part
of the first transmission filter and the first reception filter
when viewed in a plan view.
[0008] In the present invention, the first transmission filter and
the first reception filter are mounted on the circuit substrate. On
the other hand, the second transmission filter and the second
reception filter are embedded in the circuit substrate. The second
transmission filter and the second reception filter are embedded so
as to overlap at least a part of the projection region that is
formed by projecting the first transmission filter and the first
reception filter in the thickness direction of the circuit
substrate. That is, the first transmission filter and the first
reception filter are in a relatively close vicinity of the second
transmission filter and the second reception filter. In the present
invention, because the first frequency band and the second
frequency band are separated from each other by at least a
prescribed frequency range therebetween, the transmission signal
passing through the first transmission filter can be prevented from
being electromagnetically coupled with the second reception filter.
Similarly, the transmission signal passing through the second
transmission filter can be prevented from being electromagnetically
coupled with the first reception filter. This makes it possible to
achieve both the improvement in mounting density and the prevention
of the loop interference of the transmission signal with the
reception circuit.
[0009] In one preferred exemplary configuration of the present
invention, the circuit substrate may include a ground conductive
layer formed between the first transmission filter and the second
reception filter and between the second transmission filter and the
first reception filter. With this ground conductive layer, the loop
interference of the transmission signal can be prevented more
effectively.
[0010] In an exemplary configuration of the present invention, the
first transmission filter and the first reception filter constitute
a first duplexer circuit, and the second transmission filter and
the second reception filter constitute a second duplexer circuit.
In this case, in order to ensure the isolation of the transmitter
from the receiver and to improve the mounting density, it is
preferable that the first duplexer circuit be enclosed in a
package, that the package be mounted on the circuit substrate, and
that the second transmission filter and the second reception filter
be embedded in the circuit substrate as separate components. The
term "duplexer circuit" used here refers to a circuit that
electrically isolates a transmission signal from a reception signal
to allow a common antenna to be used for both the transmission and
reception in the wireless communication technology of the FDD
(Frequency Division Duplex) scheme. This circuit is also referred
to as an "antenna sharing circuit." A device that electrically
isolates two frequency bands from each other is generally called a
duplexer.
[0011] In another preferred exemplary configuration of the present
invention, the high-frequency circuit module may additionally
include a third transmission filter that filters a signal in a
third frequency band outputted from the transmission circuit and a
third reception filter that filters a signal in the third frequency
band inputted into the reception circuit, wherein the first
frequency band and the third frequency band partially overlap, or
are close to each other, and wherein the third transmission filter
and the third reception filter are mounted on the circuit substrate
so as to be at least a prescribed distance away from the first
transmission filter and the first reception filter.
[0012] In another preferred exemplary configuration of the present
invention, the high-frequency circuit module may additionally
include a fourth transmission filter that filters a signal in a
fourth frequency band outputted from the transmission circuit and a
fourth reception filter that filters a signal in the fourth
frequency band inputted into the reception circuit, wherein the
second frequency band and the fourth frequency band partially
overlap, or are close to each other, and wherein the fourth
transmission filter and the fourth reception filter are embedded in
the circuit substrate so as to be at least a prescribed distance
away from the second transmission filter and the second reception
filter.
Effects of the Invention
[0013] As described above, according to the present invention, the
first transmission filter and the first reception filter for the
first frequency band are mounted on the circuit substrate, and the
second transmission filter and the second reception filter for the
second frequency band are embedded in the circuit substrate, and
therefore, it is possible to improve the mounting efficiency.
Further, because the first frequency band and the second frequency
band are separated from each other by at least a prescribed
frequency range therebetween, the loop interference of the
transmission signal with the reception circuit can be
prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic circuit diagram of a high-frequency
circuit module.
[0015] FIG. 2 is a top view of the high-frequency circuit
module.
[0016] FIG. 3 is a cross-sectional view of the high-frequency
circuit module.
DETAILED DESCRIPTION OF EMBODIMENTS
[0017] A high-frequency circuit module according to Embodiment 1 of
the present invention will be explained with reference to figures.
FIG. 1 is a schematic circuit diagram of the high-frequency circuit
module. In the present embodiment, for ease of explanation,
configurations concerning the gist of the present invention will be
mainly explained.
[0018] A high-frequency circuit module 100 according to the present
embodiment is used for a mobile phone that is capable of handling
four frequency bands. As shown in FIG. 1, the high-frequency
circuit module 100 includes a high-frequency switch 101, first to
fourth duplexers 110, 120, 130, and 140, high-frequency power
amplifiers 151 to 154 for transmission, and an RFIC (Radio
Frequency Integrated Circuit) 160. In the actual circuit
configuration, a matching circuit, a bandpass filter for
transmission signals, and the like are provided for each frequency
band, but they are omitted in the present embodiment for ease of
explanation.
[0019] The high-frequency switch 101 switches connections from the
respective first to fourth duplexers 110 to 140 to an external
antenna 10.
[0020] The respective duplexers 110 to 140 include transmission
filters 112, 122, 132, and 142 and reception filters 114, 124, 134,
and 144, respectively. As the transmission filters 112, 122, 132,
and 142 and the reception filters 114, 124, 134, and 144, various
filters such as surface acoustic wave (SAW) filters and bulk
acoustic wave (BAW) filters can be used. In the present embodiment,
the SAW filters are used. The transmission filters 112, 122, 132,
and 142 are connected to transmission ports of the RFIC 160 through
the high-frequency power amplifiers 151 to 154, respectively. The
reception filters 114, 124, 134, and 144 are connected to reception
ports of the RFIC 160.
[0021] The RFIC 160 performs a modulation/demodulation process, a
multiplexing process, and the like to high-frequency signals. The
reception ports of the RFIC 160 that are respectively connected to
the first and third duplexers 110 and 130 are adjacent to each
other. The reception ports of the RFIC 160 that are respectively
connected to the second and fourth duplexers 120 and 140 are
adjacent to each other.
[0022] As described above, the high-frequency circuit module 100 of
the present embodiment is capable of handling four frequency bands,
and the duplexers 110 to 140 respectively filter high-frequency
signals such that only the signals of the corresponding frequency
bands can pass through.
[0023] Specifically, the first duplexer 110 is provided for W-CDMA
(Wideband Code Division Multiple Access) or LTE (Long Term
Evolution) on the 2100 MHz band. The first transmission filter 112
is a 1920 to 1980 MHz bandpass filter, and the first reception
filter 114 is a 2110 to 2170 MHz bandpass filter.
[0024] The second duplexer 120 is provided for W-CDMA or LTE on the
900 MHz band. The second transmission filter 122 is an 880 to 915
MHz bandpass filter, and the second reception filter 124 is a 925
to 960 MHz bandpass filter.
[0025] The third duplexer 130 is provided for W-CDMA or LTE on the
1900 MHz band. The third transmission filter 132 is a 1850 to 1910
MHz bandpass filter, and the third reception filter 134 is a 1930
to 1990 MHz bandpass filter. The transmission frequency range of
the first duplexer 110 and the reception frequency range of the
third duplexer 130 partially overlap.
[0026] The fourth duplexer 140 is provided for W-CDMA or LTE on the
850 MHz band. The fourth transmission filter 142 is an 824 to 849
MHz bandpass filter, and the fourth reception filter 144 is an 869
to 894 MHz bandpass filter. The reception frequency range of the
fourth duplexer 140 and the transmission frequency range of the
second duplexer 120 partially overlap.
[0027] Next, with reference to FIGS. 2 and 3, a structure of the
high-frequency circuit module 100 will be explained. FIG. 2 is a
top view of the high-frequency circuit module, and FIG. 3 is a
cross-sectional view along the line indicated by the arrows A in
FIG. 2.
[0028] As shown in FIGS. 2 and 3, in the high-frequency circuit
module 100, the RFIC 160, the first duplexer 110, and the third
duplexer 130 are surface-mounted on the top surface of the circuit
substrate 200. The first duplexer 110 is configured such that the
first transmission filter 112 and the first reception filter 114
are enclosed in a package for surface mounting. The third duplexer
130 is configured in the same manner. On the other hand, the second
duplexer 120 and the fourth duplexer 140 are embedded in the
circuit substrate 200. The second duplexer 120 and the fourth
duplexer 140 are configured such that some of the constituting
elements thereof (such as transmission filters and reception
filters) are embedded in the circuit substrate 200 as separate
components, respectively. That is, it should be noted that the
second duplexer 120 or the fourth duplexer 140 is not enclosed in a
package, unlike the first duplexer 110 and the third duplexer
130.
[0029] The circuit substrate 200 is a multi-layer substrate formed
by alternately laminating insulating layers and conductive layers.
As shown in FIG. 3, the circuit substrate 200 includes a metal
conductive layer as a core layer 210 that has excellent
conductivity and that is relatively thick, a plurality of
insulating layers 221 and conductive layers 222 that are formed on
one of the main surfaces (top surface) of the core layer 210, and a
plurality of insulating layers 231 and conductive layers 232 that
are formed on the other main surface (bottom surface) of the core
layer 210. The insulating layers 221 and 231 and the conductive
layers 222 and 232 are formed on the respective main surfaces of
the core layer 210 by the build-up method. Two of the conductive
layers 222 that are interposed between the core layer 210 and one
of the main surfaces (top surface) of the circuit substrate 200,
and one of the conductive layers 232 that are interposed between
the core layer 210 and the other main surface (bottom surface) of
the circuit substrate 200 are respectively used as ground
conductive layers 225, 226, and 235 that are provided with a
reference potential (ground). The ground conductive layers 225 and
235 are the conductive layers 222 and 232 respectively closest to
the core layer 210, and are connected to the core layer 210 through
via conductors 241, respectively. With this configuration, the core
layer 210 also serves as a ground conductor. Also, between the two
ground conductive layers 225 and 226, the conductive layer 222 is
interposed, and wiring formed on the conductive layer 222 serves as
a stripline. On one of the main surfaces (top surface) of the
circuit substrate 200, wiring 202 and conductive lands 201 for part
mounting are formed. On the other main surface (bottom surface) of
the circuit substrate 200, terminal electrodes 205 for connecting
the circuit substrate 200 to a main substrate are formed. The lands
201 have the RFIC 160, the high-frequency power amplifiers 151 to
154, the first duplexer 110, and the third duplexer 130 soldered
thereto.
[0030] In the core layer 210, penetrating holes 211 are formed to
place components therein. In the penetrating holes 211, the second
transmission filter 122 and the second reception filter 124 that
constitute the second duplexer 120 are placed, respectively.
Therefore, it is preferable that the thickness of the core layer
210 be larger than the height of the components that are placed
therein. In the present embodiment, the core layer 210 is made of a
metal plate, and more specifically, is made of a copper or copper
alloy metal plate. In the penetrating holes 211, a gap around the
component placed therein is filled with an insulator such as a
resin, which is formed integrally with the insulating layers 221
and 231. On the top surfaces of the second transmission filter 122
and the second reception filter 124, terminal electrodes 122a and
124a are formed. The terminal electrodes 122a and 124a are
respectively connected to the wiring conductive layer 222 and the
ground conductive layer 225 through via conductors 242. The fourth
duplexer 140 is embedded in the circuit substrate 200 in the same
manner as the second duplexer 120.
[0031] The features of the present invention include the following:
(a) some of the duplexers are embedded in the circuit substrate
200; (b) the embedded duplexer is located so as to overlap a part
of the projection region of the duplexer mounted on one of the main
surfaces (top surface) of the circuit substrate 200; and (c) the
frequency band of the embedded duplexer and the frequency band of
the duplexer mounted on one of the main surfaces (top surface) of
the circuit substrate 200 are separated from each other by at least
a prescribed frequency range therebetween. Specifically, (c) means
that (c1) the frequency band of the transmission filter of the
duplexer on the circuit substrate and the frequency band of the
reception filter of the duplexer embedded in the circuit substrate
are separated from each other by at least a prescribed frequency
range therebetween, and (c2) the frequency band of the reception
filter of the duplexer on the circuit substrate and the frequency
band of the transmission filter of the duplexer embedded in the
circuit substrate are separated from each other by at least a
prescribed frequency range therebetween. Here, "separated from each
other by at least a prescribed frequency range therebetween" means
that the two frequency bands have a frequency range therebetween
that is large enough to prevent a transmission signal passing
through a transmission filter of one duplexer from being
electromagnetically coupled with a reception filter of the other
duplexer and flowing into the RFIC 160, in other words, large
enough to ensure the electrical isolation. This configuration can
be achieved by dividing the frequency bands that are handled by the
high-frequency circuit module 100 into two groups depending on the
frequency level, and using the embedded duplexer to handle the
frequency band that belongs to a group different from that of the
frequency band of the duplexer mounted on one of the main surfaces
(top surface) of the circuit substrate 200, for example. As a
method of dividing the frequency bands into groups, frequency bands
higher than a certain frequency (1 GHz, for example) can be grouped
into a higher range group, and frequency bands lower than the
certain frequency can be grouped into a lower range group. This
way, the above-mentioned two frequency bands can be separated from
each other over a frequency range that is at least equal to the
frequency range between the two groups.
[0032] One of the features of the present invention is that (d) a
ground conductive layer is formed between the duplexer mounted on
the circuit substrate 200 and the duplexer embedded in the circuit
substrate 200.
[0033] One of the features of the present invention is that (e) a
plurality of duplexers mounted on the circuit substrate 200 and a
plurality of duplexers embedded in the circuit substrate are
respectively placed so as to have a prescribed distance from each
other. Here, "have a prescribed distance from each other" means
that the respective duplexers are positioned so as to have spacing
therebetween that is large enough to ensure the desired reception
performance of the RFIC 160 even if a transmission signal passing
through the transmission filter of one duplexer is
electromagnetically coupled with the reception filter of the other
duplexer, in other words, large enough to ensure the electrical
isolation.
[0034] One of the features of the present invention is that (f) a
plurality of duplexers that may be used at the same time are
separately disposed; one is mounted on one of the main surfaces
(top surface) of the circuit substrate 200; and the other is
embedded in the circuit substrate 200. From the perspective of
electrical isolation and heat dissipation, it is more preferable to
place the embedded duplexer so as not to overlap the projection
region of the duplexer mounted on one of the main surfaces (top
surface) of the circuit substrate 200.
[0035] Below, the above-mentioned features of the high-frequency
circuit module 100 according to the present embodiment will be
explained. As shown in FIGS. 2 and 3, in the present embodiment,
the transmission filter 122 and the reception filter 124 of the
second duplexer 120 are embedded in locations that overlap the
projection region of the first duplexer 110. The transmission
filter 142 and the reception filter 144 of the fourth duplexer 140
are embedded in locations that overlap the projection region of the
third duplexer 130. Further, the first duplexer 110 and the third
duplexer 130 have a distance D1 therebetween so as not to interfere
with each other. The duplexer (first duplexer 110 or third duplexer
130) mounted on the circuit substrate 200 may be used at the same
time as the duplexer (second duplexer 120 or fourth duplexer 140)
embedded in the circuit substrate 200.
[0036] According to such a high-frequency circuit module 100, the
duplexers 120 and 140 are embedded in the circuit substrate 200,
and therefore, the mounting density is improved. Also, because the
embedded duplexers 120 and 140 are respectively located so as to
overlap the projection regions of the respective duplexers mounted
on the circuit substrate 200, a high mounting density can be
achieved and various wiring lines that are connected to the
duplexers can be shortened, which improves high-frequency
characteristics.
[0037] Further, according to the high-frequency circuit module 100
of the present embodiment, a sufficient gap lies between the pass
frequency bands of the duplexers 110 and 130 mounted on the circuit
substrate 200 and the pass frequency bands of the duplexers 120 and
140 embedded in the circuit substrate 200, which can prevent the
loop interference of the transmission signal with the reception
circuit. That is, excellent electrical isolation can be achieved.
Because the ground conductive layers 225 and 226 are formed between
the duplexers 110 and 130 mounted on the circuit substrate 200 and
the duplexers 120 and 140 embedded in the circuit substrate 200,
the electrical isolation can be further improved. The duplexers 110
and 130 are mounted on the circuit substrate 200 so as to have at
least a prescribed distance therebetween, and therefore, an
excellent electrical isolation is ensured even when the frequency
bands of the two duplexers partially overlap, or are close to each
other.
[0038] Although not shown in FIG. 1 and the like, a matching
circuit is typically mounted near each duplexer. Components of the
matching circuit are mounted on the circuit substrate so that
adjustments after mounting can be made with ease. In the present
embodiment, although the duplexers 120 and 140 are embedded in the
circuit substrate 200, components of the matching circuits that are
connected to the duplexers 120 and 140 are mounted on the circuit
substrate 200 in locations near the duplexers 120 and 140. That is,
the matching circuit of the first duplexer 110 and the matching
circuit of the second duplexer 120 are mounted close to each other.
The matching circuits of the third and fourth duplexers 130 and 140
are provided in the same manner. In the present embodiment, because
a sufficient gap lies between the pass frequency bands of the first
and third duplexers 110 and 130 and the pass frequency bands of the
second and fourth duplexers 120 and 140, and because the ground
conductive layers 225 and 226 are provided, it is possible to
prevent interference through the matching circuits. The frequency
band of the first duplexer 110 and the frequency band of the third
duplexer 130 partially overlap, or are close to each other, and
therefore, the respective matching circuits thereof need to be
placed apart from each other so as to prevent interference
therebetween, or need to be placed so as to reduce coupling
therebetween. The frequency band of the second duplexer 120 and the
frequency band of the fourth duplexer 140 partially overlap, or are
close to each other, and therefore, the respective matching
circuits thereof need to be placed apart from each other so as to
prevent interference therebetween, or need to be placed so as to
reduce coupling therebetween. This way, interference through the
matching circuits can be prevented.
[0039] According to the high-frequency circuit module 100 of the
present embodiment, the duplexers 110 and 130 are mounted on the
circuit substrate 200, and the duplexers 120 and 140 are embedded
in the circuit substrate 200. Therefore, even when these duplexers
are used at the same time, heat generated in the duplexers,
especially in the transmission filters thereof, is not
concentrated, and the heat can be released through different paths.
This makes it possible to prevent the characteristics degradation
caused by heat.
[0040] One embodiment of the present invention has been explained
above, but the present invention is not limited to this. For
example, in the above embodiment, copper and a copper alloy were
given as examples of the material of the core layer 210, but any
material including metals, alloys, and resins can be used. The core
layer 210 may or may not have conductivity. In the above
embodiment, the circuit substrate 200 was described as a substrate
that has the core layer 210, which is relatively thick, but a
multi-layer circuit substrate that does not have the core layer 210
may be used instead. In the above embodiment, the respective
components that are mounted on the top surface of the circuit
substrate 200 are exposed, but it is also possible to provide a
case that covers the entire top surface or a part of the top
surface of the circuit substrate 200, or to seal the top surface
using a resin or the like.
[0041] In the above embodiment, the duplexers 110 and 130 that were
enclosed in the packages were mounted on the circuit substrate 200,
but it is also possible to mount the transmission filters and the
reception filters that constitute the respective duplexers on the
circuit substrate 200 as separate components. In the above
embodiment, the transmission filters and the reception filters that
respectively constitute the duplexers that are embedded in the
circuit substrate 200 were provided as separate components, but the
embedded duplexer may also be enclosed in a package. In the above
embodiment, each penetrating hole 211 formed in the core layer 210
was provided with one transmission filter or one reception filter,
but it is also possible to place a plurality of filters in one
penetrating hole 211.
[0042] The frequency bands that were described in the above
embodiment are examples, and the present invention can be
implemented for other frequency bands. Also, in the above
embodiment, a duplexer was given as an example of a multiplexer
(antenna sharing device), but the present invention can be
implemented in a multiplexer that has three or more pass frequency
bands such as a triplexer.
* * * * *