Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Akio Tsunekawa

Hiroyuki Nakamura

Keiji Onishi

Shigeru Tsuzuki

Kazunori Nishimura

Toru Yamada

Shunichi Seki

Tsutomu Igaki

Kazuo Ikeda

Shinobu Nakaya

A surface acoustic wave filter element has

Surface acoustic wave filter element, surface acoustic wave filter and communication device using the same

A saw filter of the invention has a piezoelectric substrate (), plural numbers of IDT electrodes () arranged on a surface of the piezoelectric substrate () as well as on a first surface acoustic wave propagation path, reflector electrodes () arranged at least at both ends of a first electrode pattern formed including the plural IDT electrodes (), one or more IDT electrodes () arranged on the surface of the piezoelectric substrate () as well as on a second surface acoustic wave propagation path which is different from the first surface acoustic wave propagation path and reflector electrodes arranged at least at both sides of a second electrode pattern formed including the IDT electrode (), in which the IDT electrodes () on the first surface acoustic wave propagation path are electrically connected in series by connecting wirings () and the IDT electrode () on the second surface acoustic wave propagation path is connected between the connecting wirings () and the ground (), which are arranged between the first electrode pattern and the second electrode pattern. According to this, the chip size can be made small.

Surface acoustic wave filter

A longitudinally coupled surface acoustic wave filter includes a first, second and third IDT electrodes and a first and second reflector electrodes on a piezoelectric substrate. The IDT electrodes each include a primary excitation region having &#x3bb;/2 electrode finger pitches, where &#x3bb; is the wavelength of a surface acoustic wave. The primary excitation region is phase-shifted by a certain amount in accordance with a desired passband frequency response. The IDT electrodes further include a plurality of secondary excitation regions each having electrode finger pitches different from the &#x3bb;/2 pitches. All of the electrode finger pitches of the surface acoustic wave filter thus range from 0.8&#x3bb;/2 to 1.2&#x3bb;/2, so that a loss increase caused by discontinuity between the IDT electrodes is prevented.

A surface acoustic wave filter has a piezoelectric substrate; at least an input IDT electrode arranged on the piezoelectric substrate; and at least an output IDT electrode arranged on the plezoelectric substrate. A pitch of electrode fingers of the input IDT electrode and a pitch of electrode fingers of the output IDT electrode are different from each other.

Surface acoustic wave filter and communication device using the filter

A surface acoustic wave filter has a piezoelectric substrate; at least an input IDT electrod arranged on a piezoelectric substrate; and at least an output IDT electrod arranged on the piezoelectric substrate. A pitch of electrode fingers of the input IDT electrode and a pitch of electrode fingers of the output IDT electrode are different from each other.

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Moriguchi, Japan

Akio Tsunekawa