The behavior of TM-wave scattering from two dielectric-filled semi-circular channels in a perfectly conducting substrate 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 resulting infinite series is then truncated to a finite number of terms to produce numerical results. Plotted results for the radar cross sections reveal how the scattering properties may be varied by changing several physical and geometrical parameters of the structure.