Li Honglang, Wen Jiguo, Hashimoto Ken-ya, Omori Tatsuya, Yamaguchi Masatsune
Institute of Acoustics, Chinese Academy of Sciences, Beijing 100080, China.
IEEE Trans Ultrason Ferroelectr Freq Control. 2007 Oct;54(10):1960-4. doi: 10.1109/tuffc.2007.489.
This paper describes the application of resonant single-phase unidirectional transducers (RSPUDTs) to the development of low-loss SAW filters with constant group delay in transition bands as well as in the passband. A low-loss SAW filter with constant group delay was designed and fabricated on a 128 degrees YX-LiNbO3 substrate. Experimental results were in good agreement with the design; the group delay deviation of 20 ns was realized over the range of +/-8 MHz at the center frequency of 512 MHz. The minimum insertion loss and -3 dB bandwidth were 4.3 dB and 8.5 MHz, respectively. The application of this technique is also extended to develop high-performance wideband filters employing quasi-slanted interdigital transducers.
本文描述了谐振单相单向换能器（RSPUDT）在开发具有恒定群延迟的低损耗声表面波（SAW）滤波器中的应用，该滤波器在过渡带以及通带中均具有恒定群延迟。在128°YX - 铌酸锂衬底上设计并制作了具有恒定群延迟的低损耗SAW滤波器。实验结果与设计结果吻合良好；在中心频率512 MHz时，在±8 MHz范围内实现了20 ns的群延迟偏差。最小插入损耗和 - 3 dB带宽分别为4.3 dB和8.5 MHz。该技术的应用还扩展到开发采用准倾斜叉指换能器的高性能宽带滤波器。
