Automatic Design of a CP Fan-Beam Linear Slotted Array in SIW Technology

In this paper, we present a technique for the automatic optimization of a right-hand circular-polarized (RHCP) linear slotted array in substrate integrated waveguide (SIW) technology for the so-called “last-mile”communications, in which a narrow (broad) beam is required in the elevation (azimuthal) plane. The procedure can be divided into two steps; i) the optimization of isolated single slot pairs, by means of two physics-based functionals able to minimize both slot pair back-scattering and axial-ratio, ii) the optimization of the entire linear array of slot pairs, by means of a global functional able to match the co-polar component of the synthesized aperture distribution to the target one, i.e., a uniform magnetic current distribution to radiate a narrow beam in the elevation plane. A prototype of array was optimized at 24.3GHz and measured in the bandwidth [24.1, 24.5]GHz, showing a fair agreement against full-wave simulations, thus validating the exposed techniques.