Nonsymmetrical multistrip coupler as a surface-wave beam compressor of large bandwidth

The equations for the performance of a multi strip coupler, in which the two tracks involved are of different geometries and acoustic characteristics, are presented in a convenient form that includes the effects of the strip length between the two tracks. Using this analysis, a beamwidth compressor, in which the trackwidths differ by a factor of ten, has been designed and constructed. Since the energy transfer from one track to the other is complete, the energy density in the acoustic beam is increased by a factor of ten over a very large operating bandwidth.