Input admittance of an array of rectangular waveguide radiators in presence of nonlinear phase distribution

This paper presents a method for determination of active admittances of the elements of a linear waveguide array in presence of nonlinear phase progression. Computations have been performed for a 26-element standard X-band rectangular waveguide array excited by uniform and cosine on a pedestal amplitude distribution and for a nonlinear phase distribution suitable for producing a cosecant pattern.