a new type of dielectric resonator reflectarray composed of 529 elements covering an area of 276 x 276 cm
2
is
constructed. The unit cell consists of squared DRA supported on a strip with variable slot length, a dielectric layer and a
conducting ground plane. The full phase of 360 degree of the array elements can be obtained by superposition two slot-strip
sizes. Two types of feeding were analyzed, the first is center fed reflectarray while the second is offset feed to reduce the
feeder blockage and as a result the antenna efficiency is improved. 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 rectangular X- band pyramidal 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. CST microwave studio
©
(finite integral technique) package is applied and compared with microstripes
©
package (transmission line technique) with good agreements between them. The mutual coupling between the feeding horn and the elements of the reflectarray are considered. At 10 GHz, the antenna provides a 3-dB beamwidth of 6 degree with a gain of 28 dB. The antenna bandwidth within 1dB gain variation is found to be 13% and aperture efficiency of 59%. |
