Reflectarrays using active-loaded elements: Enhancing performance by power combining

Active-loaded antenna elements (i.e. radiating elements being connected to active devices with gain, e.g. Gunn diodes and amplifiers) can be used to design optimized reflectarrays with enhanced performance overcoming the undesirable illumination edge taper. It is shown that the reflecting surfaces formed by active-loaded periodic structures, can be used for power-combining and hence, improving the aperture efficiency of reflectarrays. Here, as a preliminary study, active-loaded unit-cells are modeled as passive structures being connected to negative-resistance loads and used to design active reflectarray surfaces. Active reflectarrays operating at the center frequency of 10 GHz are proposed and their radiation performance is studied using fullwave simulations for various active loading of the elements.