Compact and wideband nanoacoustic pass-band filters for future 5G and 6G cellular radios.

Over recent years, the surge in mobile communication has deepened global connectivity. With escalating demands for faster data rates, the push for higher carrier frequencies intensifies. The 7-20 GHz range, located between the 5G sub-6 GHz and the mm-wave spectra, provides an excellent trade-off between network capacity and coverage, and constitutes a yet-to-be-explored range for 5G and 6G applications.

6-20 GHz 30% ScAlN Lateral Field-Excited Cross-Sectional Lamé Mode Resonators for Future Mobile RF Front Ends.

This article reports on 30% scandium-doped AlN (ScAlN) lateral field-excited (LFE) cross-sectional Lame' mode resonators (CLMRs) with unprecedented performance in the 6-20 GHz range. By combining high-crystallinity 30% ScAlN piezoelectric thin films, a lithographic tunability of the resonance frequency, and a simple three-mask post-CMOS compatible fabrication process, we propose a technology platform that can enable the mass production of low-loss, wideband, and compact microacoustic filtering devices spanning a wide spectrum portion on the same chip for the next-generation radio frequency front ends (RFFEs) of handsets. This article demonstrates a successful scaling of the microacoustic technology well beyond the sub-6-GHz fifth-generation (5G) band, as well as the outstanding capabilities of high-crystallinity 30% ScAlN piezoelectric layers in delivering high-quality factor ( Q ) and high-electromechanical coupling ( k ) resonators, notably exceeding the state of the art in terms of relevant figures of merit (FOMs).