General Synthesis Methodology for the Design of Acoustic Wave Ladder Filters and Duplexers

Abstract

In a scenario where the segment of wireless communication systems are allocated in an ever more crowded frequency spectrum, the design of filtering structures, stand-alone, duplexers, or multiplexers, become a challenging task. Moreover, filters based on acoustic wave resonators are the more suitable technology in this context due to the small size and the exhibited outstanding performance. However, to accommodate the technological requirements to the mask fulfillment is not straightforward unless a systematic synthesis methodology is used. Taking advantage on the nodal approach, the general synthesis methodology for ladder-type filters based on acoustic wave resonators is presented in this paper. This is a very fast procedure, which allow a better understanding of the interaction between technological constraints and filter performance. An experimental validation is proposed for a B28Rx band filter.

Keywords

• Bulk acoustic wave filters
• duplexer
• elliptic filters synthesis
• extracted pole
• non-resonating node (NRN)
• surface acoustic wave filters