An array of air vias (AVR) is used to realize a reflectarray antenna at Ka-band based on the idea of perforated substrate. The reflectarray composed of 29 × 29 elements and covering an area of 24.65 cm × 24.65 cm. The unit cell in reflectarray antenna consists of perforated substrate on ground plane with variable vias diameter. Varying the diameter of the vias can lead to 360° phase shift. The reflectarray is offset fed by a linearly polarized pyramidal horn antenna and simulated by CST and HFSS simulators. The predicted 3dB beamwidth is 6° and the peak gain is 34 dB at 30 GHz. The reflectarray can cover from 28 GHz to 32.5 GHz, or 8% bandwidth centered and aperture efficiency of 41% at 30 GHz with accepted side lobe level.