Shaped Beam Reflectarray using Aperture-Coupled Delay Lines for LMDS Central Station

An aperture-coupled reflectarray is proposed as central station antenna for Local Multipoint Distribution System (LMDS), a wireless access technology that provides broadband microwave connections in the band 10.10-10.70 GHz. The antenna must cover an azimuth 60deg sector and an elevation pattern with squared cosecant shape. The design process consists of two steps. First, a phase-only pattern synthesis technique is applied to obtain the required phase-shift distribution on the reflectarray surface to obtain the desired shaped pattern. The second stage consists of determining the length of the delay lines aperture-coupled to square patches to achieve the phase distribution synthesized in the previous step. Two independent designs corresponding to each orthogonal polarisation of the radiating element are shown. The simulated radiating patterns fulfil the specifications of the application.