Abstract|In this paper, design and simulation of two circularly polarized microstrip antennas
and there performance improvements using Electromagnetic Band Gap (EBG) structure are
given. Square shape EBGs are used in a planar structure for this cases. Sharpe resonances are
found with no harmonics and improvement of axial ratio for both of these antennas. Return loss of
these antenna is below than ¡40 dB or more lower. The e®ectiveness of the use of EBG structure
is also discussed. The operating frequencies of these antennas are 2.45 GHz and 2.50 GHz.