Surface acoustic wave multimode filter

Abstract

Abstract PURPOSE:To form a BPF which has high Q and high stability in a high frequency band, by acoustically coupling surface acoustic wave resonators, which have the same resonance frequency, on the same substrate. CONSTITUTION:On a substrate 11, numbers of couples of interdigital transducer electrodes 12 and 13 of surface acoustic wave resonators which have the same resonance frequency are arranged adjacently at right angles to the propagation direction of surface waves. When both kinds of electrodes are coupled together acoustically for resonance, two oscillation modes, or a symmetric mode and an asymmetric mode are generated at right angles to said propagation direction. When a BPF is formed by utilizing resonance frequencies of those two oscillation modes, the difference in resonance frequency is reduced to the half width of the passing band of the BPF. Thus, the BPF having high Q and high stability in a high frequency band is formed.

Inventors

• 👤 Yuzo Nakazawa
• 👤 中沢　祐三
• 👤 Kazuo Ono
• 👤 和男 小野
• 👤 Masaki Tanaka
• 👤 田中　昌喜
• 👤 Takao Morita
• 👤 孝夫 森田

Bibliographic Details