High rejection UNII 5.2GHz wideband bulk acoustic wave filters using undoped single crystal AlN-on-SiC resonators

5.24GHz bulk acoustic wave filters, utilizing undoped single crystal aluminum nitride, are reported. The filters had an absolute 4dB bandwidth of 151 MHz, a minimum insertion loss of 2.82 dB and rejection >38 dB. Resonators show k
²
_eff
of 6.32%, Q
_rnax
of 1523, and FOM of 96.