Table 1.

Acoustic properties of media and materials (20 °C) [26,27,28,29].

Material	Attenuation Coefficient (dB·cm−1 MHz−1)	Density (kg/m3)	Speed of Sound in Media (m/s)
Ultrasound Medium	0.002	1000	1481
Air	1.64	1.204	343
Plexiglass	1.13	1180	2730
Polyurethane Rubber	30	1010	1500