Simulated fractals shape for unit cell reflectarray

In this paper, simulation results of an identical unit cell with different shape of printed radiating element have been briefly discussed. Since the most severe problem in reflectarrays is narrow bandwidth, there are much efforts have been done in recent years to overcome this limitation. There are two factors that causing a narrow bandwidth of the reflectarrays which are the narrow band of the radiating elements and the differential spatial phase delay between elements on the reflectarray itself. Therefore, the main purpose of this paper is to investigate the suitable shapes of element for a better reflectarray cells development. The suitable shape means it has wider linear phase range and better gradient in degree per micrometer (°/¿m) which means the smaller value of gradient, so that when the frequency changes, the phase distribution only varies in a constant which is a little bit in degree (°) for the whole reflectarray structure. From the observation, minkowski element patch has wider linear phase range and koch-triangle element shape has better in gradient which is not quite sensitive in patch variation around its resonance region.