5-15 GHz range surface acoustic wave filters using electrode thickness difference type and new reflector bank type of unidirectional interdigital transducers

The frequency range of mobile communication systems is in the 2-GHz range and is extending to 3-4 GHz. In the next stage, SAW devices in the frequency of about 5-10 GHz will be needed. To meet the above challenges nanometer fabrication technology of below 0.2 μm, new IDT structures with wider electrode width and new unidirectional transducer fabrication techniques should be developed. In this paper we have described our studies of various IDT structures and shown the theoretical and experimental results of the high frequency unidirectional SAW filters ranging from 5 to 15 GHz. Direct writing electron beam lithography techniques are applied on 128° LiNbO₃ and an electrode width of below 0.1 μm has been obtained. Experimental results show an insertion loss of below 10 dB in the 10 GHz range and a high value of directivity has been obtained with the decrease in TTE