On the design of slotted waveguide planar arrays

A strategy for the analysis and design of slotted waveguide planar arrays is presented. The core of the method is a suitable segmentation of the antenna into two fundamental parts: one ´internal´, formed by the waveguide circuit, and the other ´external´, consisting of the half space above the plate containing the radiating slots. The internal part is further segmented into several blocks, connected to each other via their GSM, while the front plate is analyzed as a whole, in terms of modes of the slots. The two parts are then connected via the modes of the slots, which are considered as pieces of waveguides (whose length is just the conductor thickness). It is then convenient to build a database containing such GSM for discrete sets of geometrical parameters. The design reduces to the minimization of a suitable functional, obtained by interpolation of the stored data. The approach is quite general as the database can be generated by a commercial tool or/and the internal blocks may consist of waveguides of different shapes (e.g ridge waveguides).