{HEAD ~ The microwave assembly} may be {TAIL ~ a monopole microwave antenna assembly} but is preferably a dipole assembly 
{ HEAD ~ The microwave assembly } may be { TAIL ~ a monopole microwave antenna assembly } but is preferably a dipole assembly
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH