Structural Health Monitoring with Piezoelectric Wafer Active Sensors, 2nd Edition

(47)

Hence, Eq. (43) can be written as a product of the original signal amplified $M$ times and the beamforming function, i.e.,

$z(\overrightarrow{r},t)=Mf\left(t-\frac{r}{c}\right)BF(\mathbf{w},M)$ (48)

(48)

In order to study the relative effects of array spacing $d$, wavelength $\lambda$, and distance ...