Surface acoustic wave device and communications apparatus using the same
First Claim
1. A surface acoustic wave device having an interdigital transducer electrode that excites a Rayleigh wave on a main surface of an in-plane rotational ST-cut crystal plate having Eulerian angles of (0°
- , 113°
to 135°
, and ±
(40°
to 49°
)), a ratio of an electrode width (Lt) and an interelectrode pitch (Pt) of said interdigital transducer electrode being 0.5 or more and 0.65 or less,when said Eulerian angles are expressed by (φ
, θ
, and ±
ψ
), that a lower limit of ψ
is within the range of |ψ
|=|−
0.317θ
+81.82°
|, and an upper limit of ψ
is within the range of |ψ
|=|0.160θ
+27.78°
|.
1 Assignment
0 Petitions
Accused Products
Abstract
The invention provides an in-plane rotational ST-cut SAW resonator that is formed of an in-plane rotational ST-cut crystal plate having Eulerian angles of (0°, 113° to 135°, and ±(40° to 49°)). The in-plane rotational ST-cut SAW resonator can include an interdigital transducer (IDT) electrode for exciting a Rayleigh wave on the main surface. The ratio Lt/Pt of the electrode width Lt and the interelectrode pitch Pt of the IDT electrode is 0.5 or more and 0.65 or less. Accordingly, a reduction in the fluctuation in resonance frequency relative to the variations in an IDT electrode of a surface acoustic wave device by using the in-plane rotated ST-cut crystal plate around the Z′-axis can be achieved.
-
Citations
2 Claims
-
1. A surface acoustic wave device having an interdigital transducer electrode that excites a Rayleigh wave on a main surface of an in-plane rotational ST-cut crystal plate having Eulerian angles of (0°
- , 113°
to 135°
, and ±
(40°
to 49°
)), a ratio of an electrode width (Lt) and an interelectrode pitch (Pt) of said interdigital transducer electrode being 0.5 or more and 0.65 or less,when said Eulerian angles are expressed by (φ
, θ
, and ±
ψ
), that a lower limit of ψ
is within the range of |ψ
|=|−
0.317θ
+81.82°
|, and an upper limit of ψ
is within the range of |ψ
|=|0.160θ
+27.78°
|. - View Dependent Claims (2)
- , 113°
Specification
-
- Resources
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Current AssigneeSeiko Epson Corporation (Seiko Group)
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Original AssigneeSeiko Epson Corporation (Seiko Group)
-
InventorsYamazaki, Takashi, Iizawa, Keigo, Kanna, Shigeo
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Primary Examiner(s)Summons, Barbara
-
Application NumberUS10/329,445Publication NumberTime in Patent Office781 DaysField of Search333193-196, 333/133, 310/313.AUS Class Current333/193CPC Class CodesH03H 9/02543 Characteristics of substrat...H03H 9/25 Constructional features of ...
