On the use of Metal-Only Wideband Reflectarray for X/Ku band Application

A single-layer metal only reflectarray antenna is designed. The unit cell consists of a I-shaped metal with a cross-dipole slot on it. The cross-dipole slot element gives multi resonance and hence better phase and bandwidth are achieved. Since no substrate is required for the design of the structure, hence dielectric loss is ignored. The interelement spacing is kept as λ/2 (at 10 GHz). The reflectarray is designed for high gain and wideband application. A circular aperture reflectarray is designed. The diameter of the reflectarray aperture is 300 mm and it contains 314 elements. The aperture efficiency of 40.3% is obtained. The length of the inner cross dipole is varied to obtain the desired phase. A pyramidal horn antenna of 15 dBi gain is used as a feed. The gain of the reflectarray is 26.3 dBi in the broadside direction. The 3-dB gain bandwidth of 41% (10-15.2 GHz) is obtained. The side lobe level is suppressed to -16 dBi. The designed antenna can be used for satellite communication and CubeSat application.