TWO-PORT SAW RESONATOR

WIPO Patent Application WO/2004/102797

A1

A two-port SAW resonator comprising a pair of reflectors (101 and 105) and three IDTs (102, 103, 104) are provided on the surface of a flat piezoelectric plate so as to suppress the occurrence of spurious interference caused by a high-order longitudinal inharmonic mode. The frequency rise rates of the second and third IDTs (102 and 104) are preset to have smaller values than that of the first IDT (103) and the rate of the first IDT (103) is preset to be between 2,000 and 12,000 ppm. In additional, the electrode finger logarithms of the second and third IDTs (102 and 104) are preset to be 2.75 to 3.75 of the sum total of the electrode finger logarithms of all IDTs or logarithm of a quarter of the sum total so as to suppress the occurrence of spurious interference caused by a high-order longitudinal inharmonic mode and, at the same time, to reduce the equivalent series resistance to about 20 &ohm . Thus, the frequency stability of the two-port SAW resonator can be improved in a high frequency band of 500 MHz or above.

TAKAGI MICHIAKI (JP)
YAMAZAKI TAKASHI (JP)

PCT/JP1998/001569

November 25, 2004

April 03, 1998

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TAKAGI MICHIAKI (JP)
YAMAZAKI TAKASHI (JP)

H03H9/25; (IPC1-7): H03H9/145; H03H9/25

JPH07122964A	1995-05-12
JPH0637583A	1994-02-10
JPH05335881A	1993-12-17
JPH05267990A	1993-10-15
JPH05251988A	1993-09-28
JPH05160665A	1993-06-25
JPH04265009A	1992-09-21
JPH0296414A	1990-04-09
JPH08288782A	1996-11-01

Suzuki, Kisaburo c/o Intellectual Property Department (Seiko Epson Corporation 3-5, Owa 3-chom, Suwa-shi Nagano-ken, JP)

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