{HEAD ~ An improvement} of {TAIL ~ 3 dB} was thus achieved, as compared with the prior art 
{ HEAD ~ An improvement } of { TAIL ~ 3 dB } was thus achieved , as compared with the prior art
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH