On-Chip Compact Surface Acoustic Wave Topological Delay Line Design

Surface acoustic wave (SAW) delay lines are widely used in RF signal processing, gyrometers and sensing, especially radar. Core devices in radar require simple and compact SAW delay lines. In traditional ones based on electroacoustic interdigital transducers, increasing delay time has limitations. Here, we present an on-chip SAW delay line using the bending immunity of the topological protected edge state. By folding the transmission path and modulating the SAW velocity, it can get large delay time in a compact structure. This work helps the application of advanced artificial materials in integrated devices.