Patent ID: 6642813
Filing Date: 2003-11-04
Classification: H03H

Abstract:
A surface acoustic wave (SAW) device having SAW-exciting interdigital transducers placed on a ZnO layer laminated on a thin dielectric film made of a diamond layer formed singly or formed on a substrate, the SAW device being characterized by the conditions of:(a) providing a two-dimensional orthogonal-coordinate system, in which the axis of abscissa is represented by (2&pgr;Â·H/&lgr;M) and the axis of ordinate is represented by dm, where H signifies the thickness of the ZnO layer, &lgr;M signifies the wavelength of a harmonic of a SAW, and dm signifies the line width of the interdigital transducers (IDTs); (b) in the orthogonal-coordinate system, connecting: point A given by the coordinates, (2&pgr;Â·H/&lgr;M)=2.2 and dm=0.750; point B given by the coordinates, (2&pgr;Â·H/&lgr;M)=2.5 and dm=0.812; point C given by the coordinates, (2&pgr;Â·H/&lgr;M)=3.0 and dm=0.826; point D given by the coordinates, (2&pgr;Â·H/&lgr;M)=4.0 and dm=0.738; point E given by the coordinates, (2&pgr;Â·H/&lgr;M)=5.0 and dm=0.644; point F given by the coordinates, (2&pgr;Â·H/&lgr;M)=5.4 and dm=0.563; point G given by the coordinates, (2&pgr;Â·H/&lgr;M)=5.0 and dm=0.506; point H given by the coordinates, (2&pgr;Â·H/&lgr;M)=4.0 and dm=0.513; point I given by the coordinates, (2&pgr;Â·H/&lgr;M)=3.0 and dm=0.574; point J given by the coordinates, (2&pgr;Â·H/&lgr;M)=2.5 and dm=0.638; and point A; in this order to provide a range ABCDEFGHIJA surrounded by 10 lengths of lines;(c) structuring the SAW device so that (2&pgr;Â·H/&lgr;M) and dm can fall within the range ABCDEFGHIJA including the surrounding 10 lengths of lines; (d) producing the SAW device with the IDTs having a line width of 0.5 &mgr;m or more; (e) utilizing the fifth harmonic in the 1st-order mode of the SAW excited by the IDTs; and (f) operating the SAW device at a frequency not less than 9.5 GHz and not more than 10.5 GHz.