Offset-Fed Metal-Only Reflectarray Antenna Designs

In this work, we present two offset-fed metal-only reflectarray designs that are suitable for space applications in which the use of dielectrics is not desired. Crossed-slot type of elements are used to achieve the phase shift coverage of 360° in both of these reflectarray designs. Two illustrative design examples are presented. The first of these is a reflectarray which points the beam in the specular direction with the illumination incident from a feed horn that has a skew angle of 30°, while the second design points the beam at 0°, i.e., toward boresight. We present the simulated results of these designs and compare their performances. The simulated gain for the normal-directed beam is found to be 26.2 dBi at 35.6 GHz with an aperture efficiency of 25.5%, and the sidelobe level is -19dB. The corresponding values for the reflectarray with specular-directed beam are; gain of 28 dBi at 35.6 GHz, aperture efficiency of 35.4% and sidelobe level of -21dB