Wave transmission lines and networks – Coupling networks – Wave filters including long line elements
Reexamination Certificate
2002-08-06
2004-07-27
Lee, Benny (Department: 2817)
Wave transmission lines and networks
Coupling networks
Wave filters including long line elements
C333S185000
Reexamination Certificate
active
06768399
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a laminated band pass filter which is mainly mounted in a high frequency radio device such as a cellular phone, high frequency radio device and laminated bandpass filter manufacturing method.
BACKGROUND ART
With miniaturization of communication equipment, a laminated bandpass filter is used in an RF circuit of a cellular phone, etc. in recent years. With reference to the attached drawings, an example of the above-described conventional bandpass filter will be explained.
FIG. 7
shows an exploded perspective view of a conventional laminated bandpass filter and
FIG. 8
shows an equivalent circuit diagram of the conventional laminated bandpass filter.
As shown in
FIG. 7
, the laminated bandpass filter is constructed of dielectric layer
701
to dielectric layer
710
laminated one atop another. An internal grounding electrode
711
is placed on the dielectric layer
701
and capacitor electrodes
712
and
713
are placed on the dielectric layer
702
.
Furthermore, strip lines
714
and
715
are placed on the dielectric layer
703
and strip lines
716
and
717
are placed on the dielectric layer
704
and strip lines
718
and
719
are placed on the dielectric layer
705
. Capacitor electrodes
720
and
721
are placed on the dielectric layers
706
and
707
respectively and capacitor electrodes
722
and
723
are placed on the dielectric layer
708
, and capacitor electrodes
724
and
725
are placed on the dielectric layer
709
.
The capacitor electrode
712
, one end
718
a
of the strip line
718
and the capacitor electrode
721
are connected to the capacitor electrode
722
via a via hole
726
and the capacitor electrode
713
, one end
719
a
of the strip line
719
and the capacitor electrode
720
are connected to the capacitor electrode
723
via a via hole
727
.
Furthermore, the other end
718
b
of the strip line
718
is connected to one end
716
a
of the strip line
716
via a via hole
728
and the other end
719
b
of the strip line
719
is connected to one end
717
a
of the strip line
717
via a via hole
729
.
Furthermore, the other end
716
b
of the strip line
716
is connected to one end
714
a
of the strip line
714
via a via hole
730
and the other end
717
b
of the strip line
717
is connected to one end
715
a
of the strip line
715
via a via hole
731
. The internal grounding electrode
711
and strip lines
714
and
715
are connected to a grounding electrode
732
formed on the side of the laminated electronic part and the capacitor electrodes
724
and
725
are connected to an input electrode
733
and an output electrode
734
respectively.
An operation of the conventional laminated bandpass filter will be explained shortly using FIG.
7
and
FIG. 8. A
capacitor C
81
is formed between the capacitor electrode
724
and the capacitor electrode
722
and a capacitor C
82
is formed between the capacitor electrode
725
and the capacitor electrode
723
.
Furthermore, a capacitor C
83
is formed between the capacitor electrode
721
and the capacitor electrode
720
. Further, capacitors C
84
and C
85
are formed between the capacitor electrodes
712
and
713
and the internal grounding electrode
711
respectively.
An inductor L
81
is formed of the strip lines
718
,
716
and
714
and an inductor L
82
is formed of the strip lines
719
,
717
and
715
. The capacitor C
81
is connected to the input electrode
733
and the capacitor C
82
is connected to the output electrode
734
. The capacitor C
84
and inductor L
81
are connected in parallel with the capacitor C
81
, the capacitor C
83
are connected in series to the capacitor C
81
, the capacitor C
85
and inductor L
82
are connected in parallel with the capacitor C
82
, and the capacitor C
83
is connected in series to the capacitor C
82
, and thereby a two-stage bandpass filter is formed.
DISCLOSURE OF THE INVENTION
However, in the above-described configuration, strip lines exist on multiple layers and resistance components in inductors increase, which reduces a Q value, causing a problem that it is impossible to implement a low loss and sharp bandpass filter used for the RF circuit section. Furthermore, since the strip lines are constructed on multiple layers, there is also a problem that it is difficult to implement a small and low-profile laminated body.
In view of the above-described problems, it is an object of the present invention to provide a small, low-profile and low loss laminated bandpass filter, a high frequency radio device that will realize miniaturization by mounting this laminated bandpass filter and a laminated bandpass filter manufacturing method.
One aspect of the present invention is a laminated bandpass filter comprising:
an input electrode, output electrode and grounding electrode placed on an end face of a laminated body integrating a plurality of laminated dielectric sheets;
an internal grounding electrode provided in an internal layer of said laminated body and connected to said grounding electrode;
a plurality of capacitor electrodes including at least a first and second capacitor electrodes; and
a plurality of strip lines including at least a first and second strip lines,
wherein said first and second capacitor electrodes are capacitatively coupled with said internal grounding electrode and electrically connected to one ends of said first and second strip lines, respectively,
the other ends of said first and second strip lines are electrically connected to the grounding electrode, and
said first and second strip lines are placed on said same dielectric sheet in a certain distance and thereby electromagnetically coupled within the same layer.
Another aspect of the present invention is the laminated bandpass filter, wherein said first and second strip lines have the same length and width.
Still another aspect of the present invention is the laminated bandpass filter, wherein said first and second strip lines are placed in parallel with each other.
Yet still another aspect of the present invention is the laminated bandpass filter, wherein said first and second strip lines are electrically connected to said internal grounding electrode via a via hole.
Still yet another aspect of the present invention is the laminated bandpass filter, wherein only said first and second strip lines are placed on said dielectric sheet.
A further aspect of the present invention is a laminated bandpass filter comprising:
an input electrode, output electrode and grounding electrode placed on an end face of a laminated body integrating a plurality of laminated dielectric sheets;
an internal grounding electrode provided in an internal layer of said laminated body and connected to said grounding electrode;
a plurality of capacitor electrodes including at least a first and second capacitor electrodes; and
a plurality of strip lines including at least a first and second strip lines,
wherein said first and second capacitor electrodes are capacitatively coupled with said internal grounding electrode and electrically connected to one ends of said first and second strip lines, respectively,
the other ends of said first and second strip lines are electrically connected to the grounding electrode, and
said first strip line is placed on a first dielectric sheet and said second strip line is placed on a second dielectric sheet, and said second dielectric sheet is placed directly below said first dielectric sheet and said first and second strip lines are electromagnetically coupled.
A still further aspect of the present invention is the laminated bandpass filter, wherein said first and second strip lines have the same length, width and position within the plane.
A yet further aspect of the present invention is the laminated bandpass filter, wherein said first and second strip lines are electrically connected to said internal grounding electrode via a via hole.
A still yet further aspect of the present invention is the laminated bandpass filter, further comprising:
a third capacitor electrode connected to said input electrode;
Ishizaki Toshio
Matsumura Tsutomu
Uriu Kazuhide
Yamada Toru
Lee Benny
Matsushita Electric - Industrial Co., Ltd.
RatnerPrestia
Takaoka Dean
LandOfFree
Laminated bandpass filter, high frequency radio device and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Laminated bandpass filter, high frequency radio device and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laminated bandpass filter, high frequency radio device and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3225679