Patent ID: 6455979
Filing Date: 2002-09-24
Classification: H03H,H04B

Abstract:
A coded surface acoustic wave component for an ID tag radio interrogation system, the coded surface acoustic wave component comprising:a substrate wafer having a surface with a piezoelectric material characteristic; at least one electroacoustic transducer having an interdigital structure disposed on said surface of said substrate wafer, said electroacoustic transducer producing a surface acoustic wave in said surface with a main wave propagation direction governed by said interdigital structure; and a reflector structure having reflectors functioning as code elements and spaced apart from one another in said main wave propagation direction on said surface of said substrate wafer; said substrate wafer having a position matrix for positioning said reflectors at correct distances apart, said position matrix having basic values at equal distances from one another aligned in said main wave propagation direction, in said position matrix a size of a matrix spacing is dimensioned on a basis of a movement distance which the surface acoustic wave travels within a time period predetermined by a time-dimensioned measurement inaccuracy of a system, and of the basic values of said position matrix only the basic values occupied by said reflectors as positions distributed corresponding to a respective code are those for which distances between adjacent reflectors are always at least of equal magnitude to a structure resolution resulting from a frequency bandwidth of the system.