Surface acoustic wave filter and device employing it
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsHiroshi Kushitani, Shinobu Nakaya
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Abstract
A surface acoustic wave (SAW) filter includes a first SAW resonator, a second SAW resonator connected in series to the first SAW resonator at a first node, a third SAW resonator connected in series to the second SAW resonator at a second node, a fourth SAW resonator connected in series to the third SAW resonator at a third node, a fifth SAW resonator connected between the first node and a ground, a sixth SAW resonator connected between the third node and a ground, and a first capacitance element having a capacitance and connected between the second node and a ground. This SAW filter has a sharp attenuation characteristic at a high frequency area of a pass band, thereby widening the pass band and reducing a loss at the pass band.
Claims12
A surface acoustic wave (SAW) filter comprising:
- a first SAW resonator;
- a second SAW resonator connected in series to the first SAW resonator at a first node;
- a third SAW resonator connected in series to the second SAW resonator at a second node;
- a fourth SAW resonator connected in series to the third SAW resonator at a third node;
- a fifth SAW resonator connected between the first node and a ground;
- a sixth SAW resonator connected between the third node and a ground;
- and
- a first capacitance element having a capacitance and connected between the second node and a ground.
Dependencies are inferred from the claim text.