Laterally Acoustically Coupled BAW Filters at 3.6 GHz

Laterally acoustically coupled BAW (LBAW) filters based on solidly mounted aluminium nitride microacoustics technology were designed and fabricated for 3.6 GHz frequency. The layer thicknesses and critical dimensions remain easily manufacturable and do not limit the performance significantly. The filters exhibit inductor-matched relative bandwidth of 4.1 % with minimum insertion loss of 2.6 dB. The passband of the 3.6 GHz filter shows the same shape than that for the earlier demonstrated 1.86 GHz filter, with short range ripple reduced and a parasitic sideband at a lower frequency suppressed below -10 dB by re-design.