A reflectarray antenna consists of elements of rectangular dielectric resonator (DRA) with slot loading of
different lengths is proposed for bandwidth enhancement. Two DRA sizes an two slot widths are available to tune the phase
of each element in the reflectarray so that a full 360 degrees phase shifts can be achieved by superposition. Two structures
are presented in that paper. The first is center fed reflectarray while the second is offset fed for decreasing the feeder
blockage. The antenna has 10% bandwidth for 1 dB gain variation is obviously wider than that of conventional reflectarray
antenna while the offset fed reflectarray provide better far field pattern with back lobes reduction by -5 dB and side lobe by
-2 dB. A pyramidal X-band horn was used in both reflectarrays which have 23 x 23 elements of with cells separation of 12
mm that less than 15 mm (lambda/2) for avoiding grating lobes. The analyses are carried out using the finite integration
technique (FIT) and the transmission line method (TLM) with good agreements between them. |
