Theory and experiment are presented for a device which couples travell
ing waves in an electrical transmission line with flexural waves in an
elastic beam. Coupling of the two wave types is achieved using a segm
ented piezoelectric layer adhered to the beam and connected to the tra
nsmission line. The key design parameter is the non-dimensional coupli
ng length. A simple expression for calculating its magnitude is derive
d. For the design used, this length was predicted to be four wavelengt
hs. Experiments yielded a similar value.