Surface acoustic wave multiplex mode filter

Abstract

Abstract PURPOSE:To form a BPF with high Q and stability at high frequencies, by acoustically coupling two surface acoustic wave resonators. CONSTITUTION:Two surface acoustic wave resonators are formed by arranging two multipair interdigital transducer electrodes 12 and 13 adjacently in series along the X axis (direction of propagation of surface acoustic waves) on a piezoelectric substrate 11. The resonance frequency of the resonators set identical. When the two resonators are acoustically coupled and resonated, two oscillatin modes, objective mode and antiobjective mode are generated. When a filter is formed by using the resonance frequency of both the modes, the difference between both the resonance frequencies is almost a half-amplitude level of the band width of a BPF. Thus, the BPF with high Q and stability can be formed at high frequency bands.

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