| 摘要 |
A composite surface acoustic wave filter includes an interdigitated interdigital surface acoustic wave filter having input and output terminals. Two one-port surface acoustic wave resonators are electrically connected in series to the interdigitated interdigital surface acoustic wave filter respectively at the input and output terminals, the one-port surface acoustic wave resonators having antiresonant frequencies in a stop band that is close to and higher than the passband of the interdigitated interdigital surface acoustic wave filter. Two other one-port surface acoustic wave resonators are electrically connected parallel to the interdigitated interdigital surface acoustic wave filter, the one-port surface acoustic wave resonators having resonant frequencies in a stop band that is close to and lower than the passband of the interdigitated interdigital surface acoustic wave filter.
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