Composite dispersive filter

Abstract

Abstract A surface-wave device upon whose surface an acoustic wave may be made to propagate by the transduction of an electrical signal, which may be applied to the input of the device, comprising a substrate capable of propagating an acoustic surface wave and a conductive structure disposed upon the substrate. The conductive structure includes at least two pairs of sets of linear electrodes, an input pair and an output pair, one set of each pair being interdigitated with the other set of the same pair; and a pair of bus bars connected to opposite ends of the sets of electrodes, one bus bar for each set of electrodes of the input pair and output pair. The spacing between any two adjacent electrodes of the input pair and of the output pair of sets of electrodes varies in a prescribed manner, the spacing of the output pair being a mirror image of the input pair, the unequal spacing causing a modification of the propagation characteristics of the acoustic wave. A layer of material capable of propagating an acoustic wave is chosen and disposed upon the propagating structure, the layer being disposed at least between the input and output pairs of sets of electrodes. The linear spacing of the electrodes is modified in such a manner as to compensate for the progagation characteristics of the chosen dispersive material subsequently disposed upon the electrodes, resulting in a surface wave device having a larger time-bandwidth product and pulse compression ratio than in a device not including both complementary features.

Inventors

• 👤 H Whitehouse
• 👤 De Vaart H Van

Bibliographic Details