Resistive-wall impedance of an elliptical multilayer beam pipe

In order to investigate the influence of nonuniform thickness of the coating on the impedances, the analytical expressions of the resistive-wall impedances for the elliptical multilayer beam pipe, considering the confocal interfaces, are studied in the ultrarelativistic limit. The form factors are calculated and benchmarked with the Yokoya form factors. The influences of the nonuniform thickness of non-evaporable getter coating (NEG) coating in angular direction on the impedances are discussed.