| 摘要 |
The invention relates to a band rejection filter comprising a piezoelectric substrate (S) and a serial connection of at least two pi-elements (Pi1, Pi2) which are arranged on the substrate (S). The pi-elements (Pi1, Pi2) respectively comprise at least two electro-acoustic parallel resonators (RP1, RP2) and (RP3, RP4) and at least one electro-acoustic serial resonator (RS1, RS2), and are connected by a first series inductance (IS1). Said serial connection comprises, on a first inlet, a second series inductance (ISIN) and on an outlet, a third series inductance (ISOUT). Said resonators (RP1, RP2, RP3, RP4, RS1, RS2) have a pole-zero plot of approximately 9 % or more. |
