Wave transmission lines and networks – Plural channel systems – Having branched circuits
Reexamination Certificate
2001-08-01
2003-08-19
Pascal, Robert (Department: 2817)
Wave transmission lines and networks
Plural channel systems
Having branched circuits
C333S134000, C333S204000, C333S233000
Reexamination Certificate
active
06608533
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a matching circuit chip, a filter with a matching circuit and a duplexer mainly used for high-frequency apparatuses such as cellular phones.
2. Description of the Related Art
Conventionally, a duplexer comprises a high-impedance transmission line
2004
connected between a receiving filter
2006
and an antenna terminal
2002
, and a high-impedance transmission line
2005
connected between the antenna terminal
2002
and a transmitting filter
2007
as shown in FIG.
21
. Each of the transmission lines
2004
and
2005
is used to reverse the phase of the pass band frequency of its mating filter, thereby to obtain a high impedance condition at high frequencies. The transmission line
2004
is set so that the impedance of the receiving filter
2006
becomes open at the pass band frequencies of the transmitting filter
2007
, and the transmission line
2005
is set so that the impedance of the transmitting filter
2007
becomes open at the pass band frequencies of the receiving filter
2006
. As a result, a signal to be transmitted from the transmitting terminal
2003
to the antenna terminal
2002
is not affected by the receiving filter
2006
, and a signal to be transmitted from the antenna terminal
2002
to the receiving terminal
2001
is not affected by the transmitting filter
2007
. The circuit is thus used as a duplexer operating at a desired band.
In this kind of conventional duplexer, lines are required to be formed within a substrate having a low dielectric constant so that the transmission lines thereof have a sufficiently high impedance, thereby causing a problem of making the lengths of the lines longer and making the size of the duplexer larger. In addition, in the case when chip components are used instead of the transmission lines to form a matching circuit, problems are also caused; the number of components increases, and a frequency band wherein impedance matching can be attained becomes narrow.
SUMMARY OF THE INVENTION
In order to solve the above-mentioned problems, an object of the present invention is to achieve a matching circuit chip etc. which is simple in configuration and compact in size, and requires less number of components.
The 1st invention of the present invention is a matching circuit chip of an integrated shape comprising a plurality of terminals including a terminal for connection to a transmitting circuit or a receiving circuit, an antenna terminal for connection to an antenna, a first transmission line, a second transmission line and a third transmission line,
wherein (1) one end of said first transmission line is connected to one end of said second transmission line and one end of said third transmission line, (2) the other end of said first transmission line is connected to a first terminal among said plural terminals, (3) the other end of said second transmission line is connected to said antenna terminal, and (4) the other end of said third transmission line is connected to a second terminal among said plural terminals.
With this configuration, for example, the characteristic impedances of the first and third transmission lines are converted by the second transmission line, whereby impedance matching can be attained at the antenna terminal.
The 2nd invention of the present invention is a matching circuit chip in accordance with said 1st invention, wherein one end of a fourth transmission line is connected to the connection point of said first transmission line, said second transmission line and said third transmission line, and the other end of said fourth transmission line is grounded.
With this configuration, for example, a load to the second transmission line for performing impedance conversion can be reduced, and impedance matching can be attained in a wide frequency range.
The 3rd invention of the present invention is a matching circuit chip having a configuration wherein a first shield electrode is disposed on the upper surface of a first dielectric layer, a second dielectric layer is laid (laminated)on said first shield electrode, a first transmission line electrode is disposed on the upper surface of said second dielectric layer, a third dielectric layer is laid on said first transmission line electrode, a second transmission line electrode is disposed on the upper surface of said third dielectric layer, a fourth dielectric layer is laid on said second transmission line electrode, a third transmission line electrode is disposed on the upper surface of said fourth dielectric layer, a fifth dielectric layer is laid on said third transmission line electrode, a second shield electrode is disposed on the upper surface of said fifth dielectric layer, a sixth dielectric layer is laid on said second shield electrode, and at least four end surface electrodes are disposed on the side surfaces of a dielectric comprising said stacked dielectric layers, wherein one end of said first transmission line electrode, one end of said second transmission line electrode and one end of said third transmission line electrode are electrically connected to one another, said end surface electrode connected to the other end of said first transmission line electrode is used as a first filter connection terminal, said end surface electrode connected to the other end of said second transmission line electrode is used as an antenna terminal, said end surface electrode connected to the other end of said third transmission line electrode is used as a second filter connection terminal, and said end surface electrodes connected to said first shield electrode and said second shield electrode are grounded.
With this configuration, for example, the transmission lines are formed in the dielectric layers, whereby the lengths of the lines can be shortened, and a compact matching circuit can be formed.
The 4th invention of the present invention is a matching circuit chip having a configuration wherein a first shield electrode is disposed on the upper surface of a first dielectric layer, a second dielectric layer is laid (laminated) on said first shield electrode, a first transmission line electrode is disposed on the upper surface of said second dielectric layer, a seventh dielectric layer is laid on said first transmission line electrode, a third shield electrode is disposed on the upper surface of said seventh dielectric layer, a third dielectric layer is laid on said third shield electrode, a second transmission line electrode is disposed on the upper surface of said third dielectric layer, an eighth dielectric layer is laid on said second transmission line electrode, a fourth shield electrode is disposed on the upper surface of said eighth dielectric layer, a fourth dielectric layer is laid on said fourth shield electrode, a third transmission line electrode is disposed on the upper surface of said fourth dielectric layer, a fifth dielectric layer is laid on said third transmission line electrode, a second shield electrode is disposed on the upper surface of said fifth dielectric layer, and a sixth dielectric layer is laid on said second shield electrode, and at least four end surface electrodes are disposed on the side surfaces of a dielectric comprising said stacked dielectric layers, wherein one end of said first transmission line electrode, one end of said second transmission line electrode and one end of said third transmission line electrode are electrically connected to one another, said end surface electrode connected to the other end of said first transmission line electrode is used as a first filter connection terminal, said end surface electrode connected to the other end of said second transmission line electrode is used as an antenna terminal, said end surface electrode connected to the other end of said third transmission line electrode is used as a second filter connection terminal, and said end surface electrodes connected to said first shield electrode, said second shield electrode are grounded, said third shield electrode and said fourth shield electrode are gr
Fujikawa Makoto
Ishizaki Toshio
Kushitani Hiroshi
Nakakubo Hideaki
Yamada Toru
Glenn Kimberly E
Matsushita Electric - Industrial Co., Ltd.
Pascal Robert
Smith , Gambrell & Russell, LLP
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