Title:
LONGITUDINAL COUPLING DOUBLE MODE SAW FILTER
Document Type and Number:
Japanese Patent JP3160023
Kind Code:
B2
Abstract:
PURPOSE: To obtain the longitudinal coupling double mode SAW filter having a wide specific band in a high frequency area, and also, of a low loss by bringing an interval between each IDT close to a specific range, and forming integrally each electrode finger on the innermost side of the IDT.
CONSTITUTION: 16 pairs of IDTs(inter-digital transducers) 5, and 10 pairs of IDTs 6, 6 are arranged on a 64° Y cut -X propagation LiNbO3 substrate 1, and on both its sides, respectively, and as for a reflector 4, 250 pieces of left and right prescribed filter elements are produced by way of trial. Subsequently, an inter-center interval of the innermost side electrode finger in which each IDT is opposed to each other is set so as to be shown in the expression against an electrode finter period LT of each IDT (equal substantially to wavelength λof an excited surface acoustic wave SAW). In this regard, in the expression, (n)=2-5. In such a way, whenever a value of the inter-center interval is varied by λ/2, a peak of passing band width appears, and 3-4% specific band can be satisfied.
Inventors:
Takao Morita
Yoshitaka Watanabe
Yuji Ogawa
Takefumi Kurosaki
Yoshitaka Watanabe
Yuji Ogawa
Takefumi Kurosaki
Application Number:
JP23415191A
Publication Date:
April 23, 2001
Filing Date:
August 21, 1991
Export Citation:
Assignee:
Toyo Communication Equipment Co., Ltd.
International Classes:
H03H9/145; H03H9/64; (IPC1-7): H03H9/64
Domestic Patent References:
| JP1231417A | ||||
| JP1212015A | ||||
| JP61192112A | ||||
| JP5579124U |