This work presents a class of micro-electro-mechanical system (MEMS)-driven radio frequency filters in the X-band. The X-band center frequencies are achieved by resorting to the third-order antisymmetric Lamb wave mode (A3) in a 650-nm-thick Z-cut lithium niobate thin film. A novel bandwidth (BW) widening technique based on using the self-inductance of the top interdigital transducers and bus lines is proposed to overcome the limitations set by the electromechanical coupling ( ${k} _{t}^{2}$ ) and satisfy the demands in miniaturization and wide BW. Four different designs of the filters are designed and fabricated to show the trade-off among BW, insertions loss (IL), out-of-band rejections, and footprint. Due to the spurious-free and high- ${Q}$ performance of the A3 lithium niobate resonators, the fabricated A3 lithium niobate filters have demonstrated small in-band ripples and sharp roll-offs. One of these fabricated has demonstrated a 3-dB BW of 190 MHz, an IL of 1.5 dB, and a compact footprint of 0.56 mm ² . Another design is fabricated to demonstrate a 3-dB BW of 170 MHz, an IL of 2.5 dB, an out-of-band rejection of 28 dB, and a compact footprint of 1 mm ² .

中文翻译：

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使用铌酸锂声谐振器的X波段微型滤波器和带宽扩展技术

这项工作介绍了X波段中一类由微机电系统（MEMS）驱动的射频滤波器。X波段中心频率是通过在650 nm厚的Z形切割铌酸锂薄膜中采用三阶反对称Lamb波模式（A3）来实现的。提出了一种基于顶部叉指换能器和总线的自感的新型带宽（BW）加宽技术，以克服机电耦合设置的限制（ $ {k} _ {t} ^ {2} $ ）并满足小型化和宽BW的要求。设计和制造了四种不同设计的滤波器，以显示带宽，插入损耗（IL），带外抑制和覆盖区之间的权衡。由于无杂散和高 $ {Q} $ 由于A3铌酸锂谐振器具有出色的性能，因此制造的A3铌酸锂滤波器具有较小的带内纹波和陡峭的滚降。其中之一已展示出190 MHz的3 dB BW，1.5 dB的IL和0.56 mm ²的紧凑型占板面积 。制造了另一种设计，以演示170 MHz的3 dB BW，2.5 dB的IL，28 dB的带外抑制和1 mm ²的紧凑型占位面积 。