Variation of the transmission coefficients T_c associated with the antennas with frequency. They are nearly equal for both antennas and for varying number, positions, and sizes of the scatterers. Therefore, the average over the respective ensembles composed of the realizations with, respectively, one and three disks, is shown for the average transmission coefficients for the cavities with no disk (green dots), one added disk (black squares), and three added disks (red triangles). To guide the eye of the reader the symbols are connected by dashed lines.