Accurate Design of Planar Slotted SIW Array Antennas

A general and accurate design method based on the Method of Least Squares is developed to resonant planar substrate integrated waveguide (SIW) arrays fed by slot couplers. In this approach, which uses Elliott´s design formulas by the concept of the equivalent waveguide, a multiterm error function for achieving the input impedance matching and the desired pattern synthesis is formulated and minimized by an efficient hybrid optimization method. For accuracy verification purpose, an SIW slot array with 3×6 elements is considered. The results of the proposed method without further optimization by the full-wave simulations are compared to the results of the simulation software (Ansoft HFSS and CST), and it shows a good agreement.