The magnetic field dependence of submillimeter wave propagation in a two-la
yer parallel-plate waveguide containing n-type or p-type InSb slab has been
experimentally studied at 526 GHz and 671 GHz. in each case, a resonant pe
ak appealed on the transmission corresponding to the theoretically predicte
d slow surface wave resonance. Particularly with n-InSb, nonreciprocity of
at least 20 dB was experimentally observed for transmission at the applied
magnetic field of 0.2 T.