Reference text for Co-axial waveguide?

Does anybody know of a good reference text for co-axial waveguide?

I want to design a dual band feed for a front fed parabolic dish. One band is twice the frequency of the other. The lower band will be fed via co-axial waveguide excited in the TE11 mode. The higher frequency will be fed through a hollow cylinder (The cylinder is dual purpose, circular waveguide for the higher frequency band and also forming the centre conductor of the coaxial waveguide).

Thanks for any help.

David.