射频前端滤波器研究

Research of radio frequency front-end filters

通信技术的持续发展对射频前端滤波器提出了低插入损耗、高带宽的技术要求。本文综述了几种射频前端滤波器的主要特点和前沿研究进展,包括功率容量大但体积也大的腔体滤波器;传输速度快但工艺受限的陶瓷滤波器;体积小、功耗低但不适用于高频的声表面波滤波器;目前主流的各方面性能良好但不适用于高带宽的薄膜体声波滤波器;较新的适用于高频和高带宽的横向激发体声波滤波器;能在单一基片上集成多种无源元件且以小型化和高集成度为特点的集成无源器件滤波器;以及可以构建三维集成电路且应用于汽车和航空航天领域的低温共烧陶瓷滤波器。从研究结果来看,薄膜体声波滤波器是目前综合性能最好也是最主流的滤波器,而横向激发体声波滤波器是具有探索价值的滤波器。

With the continuous development of communication technology,the technical requirements of low insertion loss and high bandwidth are put forward for radio frequency(RF)front-end filters.In this paper,the main characteristics and advanced research progress of several RF front-end filters are reviewed,including cavity filters with large power capacity but large volume and ceramic filters with fast transmission speed but limited process.Surface acoustic wave(SAW)filters are small in size and low in power consumption but not suitable for high frequency.Film bulk acoustic resonator(FBAR)filter is the mainstream filter with good performance in all aspects but not suitable for high bandwidth.Laterally-excited bulk acoustic resonator(XBAR)filter is a relatively new filter suitable for high frequency and high bandwidth.The integrated passive device(IPD)filter can integrate a variety of passive components on a single substrate and is characterized by miniaturization and high integration.Low temperature cofired ceramic(LTCC)filters can build 3D integrated circuits for automotive and aerospace applications.Based on the current research results,FBAR filter is the most popular filter with the best comprehensive performance at present,and XBAR is a filter with great exploration value in the future.