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US 7,741,930 B2Granted
Filter and antenna duplexer
AssigneesFujitsu Media Devices Limited, Fujitsu Limited
InventorsShogo Inoue, Tokihiro Nishihara, Takashi Matsuda, Masanori Ueda
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Abstract
There is provided a filter including a first resonator, a second resonator in which an excitation efficiency is reduced more than the first resonator, and an inductor connected in parallel with the second resonator.
Claims20
A filter comprising:
- a first resonator;
- a second resonator of which an excitation efficiency is reduced more than the first resonator;
- and
- an inductor connected in parallel with the second resonator, and wherein no inductor is connected in parallel with the first resonator,
- wherein:
- the first resonator and the second resonator are surface acoustic wave resonators;
- the first resonator includes a first IDT including two first electrodes and first electrode fingers;
- all of the first electrode fingers have an identical width and an identical pitch and are alternately connected to the two first electrodes;
- and
- the second resonator includes two second IDT including two second electrodes and second electrode fingers.
7 more elements
A filter comprising:
- a first resonator;
- a second resonator of which an excitation efficiency is reduced more than the first resonator;
- and
- an inductor connected in parallel with the second resonator, and wherein no
- inductor is connected in parallel with the first resonator,
- wherein:
- the first resonator and the second resonator are piezoelectric thin film resonators;
- the first resonator includes a first lower electrode, a first upper electrode and a first piezoelectric film sandwiched between the first lower electrode and the first upper electrode;
- and
- the second resonator includes a second lower electrode, a second upper electrode and a second piezoelectric film sandwiched between the second lower electrode and the second upper electrode.
7 more elements
Dependencies are inferred from the claim text.