Wave transmission lines and networks – Coupling networks – Frequency domain filters utilizing only lumped parameters
Reexamination Certificate
2002-08-06
2004-07-06
Tokar, Michael (Department: 2819)
Wave transmission lines and networks
Coupling networks
Frequency domain filters utilizing only lumped parameters
C333S172000, C333S177000, C333S185000
Reexamination Certificate
active
06759926
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an LC filter circuit, a monolithic LC composite component, and a multiplexer used in, for example, a radio communication device such as a portable telephone, and relates to the radio communication device.
2. Description of the Related Art
A conventional monolithic LC filter is shown in FIG.
10
. The monolithic LC filter
40
includes an insulating sheet
42
on the surface of which LC-trap coil conductors
50
and
51
are provided, an insulating sheet
43
on the surface of which resonator capacitor conductors
52
and
53
are provided, insulating sheets
44
and
46
on the surfaces of which LC-trap capacitor conductors
54
,
55
,
58
and
59
are provided, respectively, an insulating sheet
45
on the surface of which input/output conductors
56
and
57
are provided, an insulating sheet
47
on the surface of which a coupling capacitor conductor
60
is provided, an insulating sheet
48
on the surface of which resonator coil conductors
61
and
62
are provided, and insulating sheets
41
and
49
on the surfaces of which ground conductors
63
and
64
are provided, respectively.
The insulating sheets
41
to
49
are laminated, and after insulating sheets for protection are placed on the top and bottom thereof, they are integrally baked. A laminate
67
shown in
FIG. 11
is thus produced. The laminate
67
has an input terminal
68
, an output terminal
69
, relay terminals
70
and
71
, and a ground terminal G provided thereon. One end
50
a
of the LC-trap coil conductor
50
and one end
56
a
of the input/output conductor
56
are connected to the input terminal
68
. A first end
51
a
of the LC-trap coil conductor
51
and a first end
57
a
of the output conductor
57
are connected to the output terminal
69
. A second end
50
b
of the LC-trap coil conductor
50
, LC-trap capacitor conductors
54
and
58
, and a first end
61
a
of the resonator coil conductor
61
are connected to the relay terminal
70
. A second end
51
b
of the LC-trap coil conductor
51
, LC-trap capacitor conductors
55
and
59
, and a first end
62
a
of the resonator coil conductor
62
are connected to the relay terminal
71
. Also, the resonator capacitor conductors
52
and
53
, the second ends
61
b
and
62
b
of the respective resonator coil conductors
61
and
62
, and the ground conductors
63
and
64
are connected to the ground terminal G.
FIG. 12
is an electrical equivalent circuit diagram of the monolithic LC filter
40
having the above-described structure. An LC resonator Q
1
includes a resonator inductor L
1
defined by the resonator coil conductor
61
, and a resonator capacitor Cl defined by opposing the resonator capacitor conductor
52
to the LC-trap capacitor conductor
54
. Likewise, an LC resonator Q
2
includes a resonator inductor L
2
defined by the resonator coil conductor
62
, and a resonator capacitor C
2
defined by opposing the resonator capacitor
53
to the LC-trap capacitor conductor
55
. These LC resonators Q
1
and Q
2
are capacitively coupled through a coupling capacitor C
3
defined by opposing the coupling capacitor conductor
60
to the LC-trap capacitor conductors
58
and
59
.
An LC trap circuit T
1
is inserted between the input terminal
68
and the LC resonator Q
1
, and an LC trap circuit T
2
is inserted between the output terminal
69
and the LC resonator Q
2
. The LC trap circuit T
1
includes an LC trap inductor L
3
defined by the LC-trap coil conductor
50
, and an LC trap capacitor C
4
defined by opposing the LC-trap capacitor conductors
54
and
58
to the input conductor
56
. Likewise, the LC trap circuit T
2
includes an LC trap inductor L
4
defined by the LC-trap coil conductor
51
, and an LC trap capacitor C
5
defined by opposing the LC-trap capacitor conductors
55
and
59
to the output conductor
57
.
In this monolithic LC filter
40
, the LC-trap coil conductors
50
and
51
defining the respective LC trap circuits T
1
and T
2
, and the resonator coil conductors
61
and
62
defining the respective LC resonators Q
1
and Q
2
, are provided on separate insulating sheets
42
and
48
, respectively. As a result, the area required to provide a conductor pattern defining a coil increases, thereby making it difficult to reduce the size and height of the LC filter
40
.
SUMMARY OF THE INVENTION
In order to overcome the problems described above, preferred embodiments of the present invention provide an LC filter circuit, a monolithic LC composite component, a multiplexer, and a radio communication device having reduced sizes and heights.
A preferred embodiment of the present invention provides an LC filter circuit including an input terminal and an output terminal, first and second LC resonators electrically connected between the input terminal and the output terminal, an input-side LC trap circuit electrically connected between the input terminal and the first LC resonator, and an output-side LC trap circuit electrically connected between the output terminal and the second LC resonator. A portion of an inductor defining the first LC resonator also provides an inductor defining the input-side LC trap circuit, and a portion of an inductor defining the second LC resonator also provides an inductor defining the output-side LC trap circuit.
Another preferred embodiment of the present invention provides a monolithic LC composite component including a laminate including a plurality of laminated insulating layers, an input terminal and an output terminal provided on the surface of the laminate, first and second LC resonators which are provided in the laminate, and each of which is defined by an LC-resonator inductor conductor and an LC-resonator capacitor conductor, an input-side LC trap including an LC-trap capacitor conductor electrically connected between the input terminal and the first LC resonator, and a portion of the LC-resonator inductor conductor defining the first LC resonator, and an output-side LC trap including an LC-trap capacitor conductor electrically connected between the output terminal and the second LC resonator, and a portion of the LC-resonator inductor conductor defining the second LC resonator.
With these arrangements, since a portion of the inductor L of the LC resonator is arranged to also provide an LC trap inductor L, it is unnecessary to separately provide an LC-trap coil conductor. As a result, an LC composite component having a greatly reduced size and height is achieved.
The multiplexer and the radio communication device according to further preferred embodiments of the present invention include a monolithic LC composite component having the above-described features. This achieves a multiplexer and a radio communication device that are compact and low-profile.
The above and other elements, characteristics, features, and advantages of the present invention will become clear from the following detailed description of preferred embodiments of the present invention in conjunction with the accompanying drawings.
REFERENCES:
patent: 5448209 (1995-09-01), Hirai et al.
patent: 5834992 (1998-11-01), Kato et al.
patent: 5945892 (1999-08-01), Kato et al.
patent: 6433653 (2002-08-01), Matsumura et al.
patent: 6504451 (2003-01-01), Yamaguchi
patent: 6529101 (2003-03-01), Tojyo et al.
patent: 6529102 (2003-03-01), Masuda et al.
patent: 6542053 (2003-04-01), Yamaguchi
patent: 6583686 (2003-06-01), Matsumura et al.
patent: 6587020 (2003-07-01), Tojyo
patent: 2002/0057139 (2002-05-01), Matsumura et al.
Keating & Bennett LLP
Murata Manufacturing Co. Ltd.
Nguyen Khai M.
Tokar Michael
LandOfFree
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