Note on the complex zeros of Hν′(x)+iζHν(x)=0

Approximations for the complex zeros in the ν-plane of the Hankel functions Hν(x) and Hν′(x) are available in terms of the zeros of Airy functions. The corresponding zeros of a linear combination of Hankel functions are of interest when scattering from cylinders with a surface impedance is studied. A simple method to compute these zeros efficiently is presented.