Field solution of an annular slot array over a radial waveguide cavity

Abstract

The problem of a cavity-backed annular slot array is solved using appropriate Green's functions for the interior and exterior regions of the cavity. The excitation is assumed to be general in form and is defined in terms of radial waveguide modes. Both interior and exterior fields are obtained using a slot field distribution yet to be determined. The continuity of the tangential slot magnetic fields is then used to set up integral equations for the slot field distributions. These slot fields are represented by a finite number of pulse functions with unknown coefficients, which are then determined using a point matching technique. The method evaluates all slot fields simultaneously and as such includes all coupling effects between the various slots. The slot field distributions and their radiation fields are computed for different array sizes, and some representative results are presented.