A novel phase compensation technique utilizing variable radii edge circular slots for reflectarray antenna element

This paper reports on investigations into the phase characteristic of a unit cell of a single layer microstrip reflectarray at 10 GHz. Different radii circular edge slots affect the current distribution and change the effective electrical path length of current thus modify resonance frequency, refection phase and reflection loss. The achieved return loss in all cases is less than 0.32 dB. Maximum attainable phase ranges for slot configuration parallel to PMC walls and PEC walls are 312° and 285° respectively. To achieve linear slope with increase value of phase range, both slot configurations are combined in spite of using thin substrate to improve antenna element bandwidth. Phase range of 339° has been obtained.