Microstrip reflectarray with QUAD-EMC element

This paper shows the performance of a reflect array using the QUAD-EMC patch as the radiating element. The phase adjustment is made at a sub-array level by tuning the length of each driven patch. Therefore, this new design uses fewer of the required phase shifter elements. The phase diagram provides the shared phase to each QUAD-EMC unit. The return loss plot of a radiating unit excited by the microstrip line is studied. The connection between the phase diagram and the return loss plot is also discussed. Experiments have shown that we can get comparable results with those obtained by controlling the phase on each individual element. Bandwidth of 23% with 1.5 dB gain variation can be achieved when built on an FR4 substrate. The cross polarization level may be improved since there is enough room to place the straight delay lines.