Abstract: In this paper,the mode matching technique is ap plied to calculate the scattered field from a 2 dimensional perfectly conductin g dihedral corner reflector illuminated by either an E pola rized or a H pola rized plane wave.A system of linear equations with scattered field expansion coe fficients as unknowns is derived.It is solved to obtain the scattered field expa nsion coefficients by computer,thereby the scattered field is calculated.Numeric al examples are presented,and they are compared with those obtained from MoM(Met hod of Moments).Good agreements are obtained.