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US 7,679,472 B2Granted
Branching filter package
AssigneeOki Semiconductor Co., Ltd.
InventorsWataru Ohashi, Hajime Shimamura, Tomokazu Komazaki, Yoshiaki Fujita
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AssigneeOki Semiconductor Co., Ltd.
InventorsWataru Ohashi, Hajime Shimamura, Tomokazu Komazaki, Yoshiaki Fujita
Estimating the term…
A branching filter package has a SAW filter chip housing area which houses a piezo electric base, on which a transmitting SAW filter and a receiving SAW filter having a different frequency passing band with each other, are formed, and an impedance matching circuit and a branching circuit for the transmitting SAW filter and the receiving SAW filter.
The surface acoustic wave duplexer comprising:
A surface acoustic wave duplexer comprising:
A surface acoustic wave (SAW) duplexer comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Multiple-port networks comprising only passive electrical elements as network components: impedance-matching networks
For duplexers: including surface acoustic wave [SAW] devices
Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source:…
Networks using surface acoustic waves: duplexers
Term ended 5 May 2019 (estimated)
1. Field of the Invention
The present invention relates to a branching filter that is used in small mobile communication devices such as mobile cellular phones. In particular, the present invention relates to branching filters and the construction of branching filter packages that use a high Radio Frequency (RF) filter as an elastic Surface Acoustic Wave (SAW) resonator type filter (called a SAW filter below) to achieve increased miniaturization and high performance.
2. Description of the Related Art
FIG. 1 illustrates an example of the structure of the SAW branching filter described in the first embodiment of the present invention.
FIG. 2 shows the concrete circuit structure of the SAW branching filter described in the first embodiment of the present invention.
FIG. 3 shows the concrete circuit structure of the SAW branching filter described in the first embodiment of the present invention.
The invention will now be described based on the preferred embodiments, which do not intend to limit the scope of the present invention, but exemplify the invention. All of the features and the combinations thereof described in the embodiment are not necessarily essential to the invention.
FIG. 1 is the block diagram showing an example of the structure of the SAW branching filter described in the first embodiment of the present invention. As shown in FIG. 1, the SAW branching filter 100 comprises the antenna terminal 101, transmitting terminal 103 and receiving terminal 104. The impedance matching LC circuit 102 is connected to the antenna terminal 101. The transmitting side branching circuit (called the Tx-branching circuit from now on) 105 and the transmitting SAW filter 108 are connected between the impedance matching LC circuit 102 and the transmitting terminal 103.
The receiving side branching circuit (called the Rx-branching circuit from now on) 106 and the receiving SAW filter 109 are connected between the impedance matching LC circuit 102 and the receiving SAW filter 109. The transmitting SAW filter 108 and the receiving SAW filter 109 have different frequency pass bands. Although the branching circuit 107 is constructed from the Tx-branching circuit 105 and the Rx-branching circuit 106, depending on the design requirements, Tx-branching circuit 105 does not have to be included.