circular waveguides

Hi,

I need the calculation to obtain Cylindrical waveguides attenuation.

I Know Inian's book formula.

But I don′t known how he can get this formula.

There are some simplification with the first Kind Bessel functions, But I can′t get to his formula.

I am very grateful with some help.

Thanks

have you seen pozar's "Microwave Engineering" I think he made the derivation for the fundamental mode TE11

its here look for the cir wg

pl