This paper presents radio frequency (RF) microelectromechanical system (MEMS) filters with extremely high bandwidth widening capability. The proposed filtering topologies include hybrid configurations consisting of piezoelectric MEMS resonators and surface-mounted lumped elements. The MEMS resonators set the center frequency and provide electromechanical coupling to construct the filters, while the lumped-element-based matching networks help widen the bandwidth (BW) and enhance the out-of-band rejection. Aluminum nitride (AlN) S0 Lamb wave resonators are then applied to the proposed filtering topologies. AlN S0 first- and second-order wideband filters are studied and have shown prominent performance. Finally, the AlN S0 first-order wideband filter is experimentally implemented and characterized. The demonstrated first-order filter shows a large fractional bandwidth (FBW) of 5.6% (achieved with a resonator coupling of 0.94%) and a low insertion loss (IL) of 1.84 dB. The extracted bandwidth widening factor (BWF) is 6, which is approximately 12 times higher than those of the current ladder or lattice filtering topologies. This impressive bandwidth widening capability holds great potential for satisfying the stringent BW requirements of bands n77, n78, and n79 of 5G new radio (NR) and will overcome an outstanding technology hurdle in placing 5G NR into the marketplace.

本文介绍了具有极高带宽展宽能力的射频 (RF) 微机电系统 (MEMS) 滤波器。所提出的滤波拓扑包括由压电 MEMS 谐振器和表面安装集总元件组成的混合配置。 MEMS 谐振器设置中心频率并提供机电耦合来构建滤波器，而基于集总元件的匹配网络有助于加宽带宽 (BW) 并增强带外抑制。然后将氮化铝 (AlN) S0 兰姆波谐振器应用于所提出的滤波拓扑。对AlN S0一阶和二阶宽带滤波器进行了研究，并表现出了突出的性能。最后，实验实现并表征了 AlN S0 一阶宽带滤波器。演示的一阶滤波器显示出 5.6% 的大分数带宽 (FBW)（通过 0.94% 的谐振器耦合实现）和 1.84 dB 的低插入损耗 (IL)。提取的带宽加宽因子 (BWF) 为 6，大约比当前梯形或点阵滤波拓扑的带宽加宽因子高 12 倍。这种令人印象深刻的带宽扩展能力具有满足 5G 新无线电 (NR) 频段 n77、n78 和 n79 严格带宽要求的巨大潜力，并将克服将 5G NR 推向市场的突出技术障碍。