Experimental measurements and numerical results for supercoupling channel. (a) Numerical and experimental comparison for the transmission phase and amplitude. Radiation and material loss from the intermediate channel were modeled using elastic shell boundary conditions with a loss tangent of 0.05. Note that curve (ii), in green, shows the transmission amplitude at the tunneling frequency (~765 Hz) is much higher than the others, due to the use of thicker walls for the intermediate channel. The experimental parameters were a = 0.450 m, b = 0.382 m, and d = 12.6 mm. (b) Spatial phase distribution through the CNZ channel at the tunneling frequency for configurations with different lengths and ftunneling (i) = 769.6 Hz, ftunneling (ii) = 769.6 Hz, and ftunneling (iii) = 769.4 Hz.