针对 B25 SAW 双工器设计需求，基于压电复合单晶薄膜（POI）衬底开展了仿真、实测与性能对比研究。首先通过有限元仿真和实测对比了 42°LT-POI 与 50°LT-POI 谐振器的主模和远端杂波特性；然后对 B25 双工器的发射端（TX）和接收端（RX）分别进行了拓扑结构设计；最后通过实测对比了两种不同切型 POI 衬底的 B25 双工器电性能参数。结果显示，在其他指标相当的情况下，相较于 50°LT-POI，采用 42°LT-POI 衬底的 B25 双工器具有更优的远端抑制性能。

This study conducted a comprehensive study involving simulation， experimental measurements， and performance comparison using a piezoelectric-on-insulator （POI） substrate to address the design requirements of a B25 SAW duplexer. Through finite element simulations and experimental measurements， the fundamental mode and farend spurious mode of 42°LT-POI and 50°LT-POI resonators were rigorously analyzed. Topological structural designs were implemented for the transmitter and receiver sections of the B25 duplexer. The electrical performances of experimental prototypes fabricated on these two distinct crystal-cut POI substrates were evaluated. Comparative results demonstrate that the duplexer with the 42°LT-POI substrate achieves superior far-end suppression performance while maintaining comparable specifications to the B25 duplexer with the 50°LT-POI substrate.

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