18 GHz Microacoustic ScAlN Lamb Wave Resonators for Ku Band Applications

This work reports on the designing, manufacturing, and characterization of 18 GHz microacoustic 30% scandium aluminum nitride doped lamb wave Cross-Sectional Lamé Mode Resonators (CLMRs) for K u band applications, with a specific focus on the next generation of radio frequency filters for 5G and satcom applications.Measured results highlight a 3 dB quality factor (Q 3dB ) as high as 180, a mechanical quality factor (Q m ) greater than 350, and an electromechanical coupling ($k_t^2$) of 7.5% for 50 Ω matched CLMRs at 18 GHz, while preserving CMOS compatibility, resonant frequency lithographic tunability, and a 3-mask fabrication process. The devices also demonstrated a P 1dB compression point greater than 12 dBm and a temperature coefficient of frequency of −40 ppm/K.Simulated filter responses based on CLMRs modeling and measured data showcase 3 dB fractional bandwidths (FB % ) greater than 4%, with out-of-band-rejection and selectivity greater than 20 dBc and 15 dBc, respectively, confirming the suitability of the reported technologies for the manufacturing of the next generation of K u band applications.