The behavior of TM-wave scattering from both semi-circular channels and bosses in a conducting plane is investigated. The scattered field is represented in terms of an infinite series of radial modes with unknown coefficients. By applying separation of variables and employing the partial orthogonality of sine functions, the unknown coefficients are obtained. The boundary conditions are checked for semi-circular channels and bosses to verify the algorithm proposed. Plotted results for the radar cross sections reveal how the scattering properties may be varied by changing several physical and geometrical parameters of the structures.