2.4GHz AlN Thin Film Acoustic Delay Lines

This work presents the design and analysis of 2.4 GHz acoustic delay lines (ADLs) based on AlN thin film. Thickness-field-excited single-phase unidirectional transducer (TFE-SPUDT) design is implemented for acoustic waves to travel more efficiently. The structure parameters including wavelength, aperture and cell number of the devices are analyzed and optimized by finite element analysis (FEA) to satisfy specific frequency band and low insertion loss. Besides, different gap lengths are also simulated to extract the group delay and phase velocity. The results show a minimum insertion loss (IL) of 1.043 dB and a 3-dB bandwidth (BW) of 133.1 MHz at the center frequency of approximately 2.414 GHz. For fundamental symmetric (S0) lamb waves, the phase velocity is extracted as approximately 10313 m/s. With the feature of CMOS-compatible, the high frequency ADLs based on AlN thin film are potential candidates for RF microsystem to fulfill signal processing.