Wave propagation in ring shaped excitable medium having inhomogeneity with circular symmetry is studied experimentally, theoretically and with numerical simulations. Geometrical wave theory is used to determine the front shape from the propagation velocity function. An open reactor is constructed to study the propagation of chemical waves experimentally in an inhomogeneous Belousov-Zhabotinsky excitable media. The shape of the rotation invariant front is determined and a software is developed to determine the local propagation velocity. The invariant front shapes are compared with simulation results based on the geometrical wave theory. (C) 2009 Elsevier B.V. All rights reserved.