Increasing the maximum operating frequency of SAW filters fabricated using an I-line source

Abstract

The operation frequency of the SAW filters with the unbalance structure is more than that with the unbalance one. In this study, “how to use the unbalanced structure technique to increase the maximum operating frequency (MOF) of surface-acoustic wave (SAW) filters” is studied. The operating frequency (OF) is limited by the gap width but independent of the line width. The MOF is less than or equal to 27/40 times the acoustic wave velocity/the gap width. A gap width of 0.35 μm can be easily defined using the I-line lithography. Therefore, an MOF of more than 7 GHz could be achieved. The technique of near field phase shift photolithography (NFPSL) has the potential to fabricate nano-gap width SAW devices. Fabricated by using an I-line light source with NFPSL, the SAW devices could have the potential of reaching high operating frequencies possibly over 27 GHz.