The rectangular waveguide have advantages of low loss and high power capacity
over planar waveguides such as microstrip and coplanar waveguides. Thus, these
advantages are suitable for delivering high power. However, the breakdown is
still critical in high power system. Therefore, it is important to suppress a peak
electric field which can be typically observed around discontinuity.
In this paper, we compare which type of matching structure is suitable for the
matching and peak electric field for high power system and suggest that a new
type of the matching structure which is suitable for the high power system.