The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 03, 1990
Filed:
Jul. 15, 1988
Akitsuna Yuhara, Kawasaki, JP;
Hitoshi Watanabe, Yokohama, JP;
Jun Yamada, Yokohama, JP;
Tetsuya Hirashima, Katsuta, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
When SAW filter is used as a receiving filter of an antenna duplexer filter in a cellular radio equipment, since a transmitting signal of an out-band frequency has a large power for the SAW filter, the large power can leak into the SAW filter to generate inter-modulation disturbances in the SAW filter. Since the inter-modulation disturbances are generated when the transmission power density of the surface acoustic wave is made too large, input converters are divided, and the divided converters are disposed in the direction perpendicular to the propagation direction of the surface acoustic wave to lower the transmission power density. Since the divided converters are connected in series, reduction in the impedence together with increase of the aperture length can be compensated.