BALANCED-UNBALANCED FILTER BASED ON LATERALLY COUPLED BAW THIN FILMS

摘要

The invention describes an acoustic balanced-unbalanced (balun) or balanced-balanced thin-film BAW filter based on lateral acoustic coupling. In laterally acoustically coupled thin- film BAW filters (LBAW) one can realize transformation from unbalanced to balanced electric signal if the electrodes of the balanced port are placed on the opposite sides of the piezoelectric film. The manufacturing process is simpler than in the corresponding component based on vertical acoustical coupling. The device can also realize impedance transformation.