A new rigorous iterative process is proposed for studying a rectangular wav
eguide which includes the Gunn diode GaAs AH445 (THOMSON). It consists in g
enerating a recursive relationship between a given wave source and reflecte
d waves from the discontinuity plane which is divided into cells. A high co
mputational speed has been achieved by using fast mode transformation (FMT)
. The theory as well as its implemention procedure are described. Numerical
results are successfully compared with experimental published data.