Microwave low insertion loss SAW filter by using ZnO/sapphire substrate with Ni dopant

Microwave low insertion loss SAW filters are realized by using ZnO epitaxial films on a sapphire substrate. The epitaxial growth conditions and dopant are carefully determined to realize low propagation loss and high stability. 1.5 to 2.5 GHz range SAW filters are fabricated with an insertion loss of only 1 to 2 dB and outline dimensions of 0.01 to 0.02 cc.