Dependency Of KA-Band Reflectarray Unit Cell Reflection Properties On The Spacing Between Antenna Elements

In this paper, effects of inter-element spacing on the performance of reflectarray unit cells are studied to provide guidelines for an optimum reflectarray design. A reflectarray unit cell is designed at 32 GHz which is the frequency of interest for reflectarray\u27s space applications. By changing the distance between the reflectarray elements from 0.35 to 0.85 λ0 in E plane and 0.45 to 0.95 λ0 in H plane, the resonant frequency is varied from 30.5 to 32.5 GHz (representing more than 6% change), the reflection phase is shifted by 140o, bandwidth is decreased by 4% and the maximum reflection loss is increased by 1.3 dB. To prove the concept, two 5×5 sub-arrays with different inter-element spacing are fabricated, measured and compared with simulations with good agreement. © 2013 IEEE