Or, {TAIL ~ the substrate} may further include an absorber for absorbing the surface acoustic wave propagated in {HEAD ~ the surface acoustic wave propagation region} 
Or , { TAIL ~ the substrate } may further include an absorber for absorbing the surface acoustic wave propagated in { HEAD ~ the surface acoustic wave propagation region }
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD