Back to results
US 6,472,953 B1Granted
Band switching filter using a surface acoustic wave resonator and an antenna duplexer using the same
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsToru Sakuragawa, Yuki Sato, Katsuya Fujii, Kozo Murakami, Ryoichi Takayama
Life of this patent
Estimating the term…
Abstract
A band switching filter includes a resonator circuit having a surface acoustic wave resonator, a switching element and an impedance element. The filter selectively passes or attenuates a signal through one of two pass bands using a single filter. The resonant frequency of the resonator circuit can be shifted to another frequency by selectively connecting the surface acoustic wave resonator to an impedance element using a switching element.
Claims4
A band switching filter comprising:
- a surface acoustic wave resonator,
- an impedance element coupled to a first terminal of said surface acoustic wave resonator,
- a switching element coupled to said impedance element and a second terminal of said surface acoustic wave resonator, and
- a capacitance element coupled to said first terminal of said surface acoustic wave resonator, thereby said band switching filter capable of simultaneously switching a series resonant frequency and a parallel resonant frequency of said surface acoustic wave resonator.
1 more element
An antenna duplexer comprising:
- a plurality of band pass filters having respective pass bands of different frequencies, each filter including
- i)a surface acoustic wave resonator,
- ii) an impedance element coupled to a first terminal of said surface acoustic wave resonator,
- iii) a switching element coupled to said impedance element and a second terminal of said surface acoustic wave resonator, and
- iv) a capacitance element coupled to said first terminal of said surface acoustic wave resonator, thereby said band switching filter capable of simultaneously switching a series resonant frequency and a parallel resonant frequency of said surface acoustic wave resonator,
- wherein each of said plurality of band pass filters attenuates a pass band of another of said plurality of band pass filters.
3 more elements
Dependencies are inferred from the claim text.