In this paper the phased array consist of a circular aperture antennas are arranged in linear array to study the effect of the number of elements on the radiation pattern parameters.The effect of distribution of current on each elements also studied to reduced the side lobe level.

 2-slot  HFSS  VSWR  FR4-epoxy  band width A design of 2-slot loaded rectangular microstrip patch antenna was worked out. The aim of this design is to improve the parameters of microstip antenna .This design shows that there is an increase in the bandwidth, which may distinguish it for the use in communication purposes especially in military and civil applications .The antenna has been designed selecting FR4-epoxy substrate with dielectric constant of 4.4.andoptimum dimensions of 60 × 60 × 1.66 mm 3. The design requirements for this antenna should include a VSWR less than 2 for 50 Ω reference impedance and return loss is less than to-10 dB. The simulation of this design is carried out using a high frequency simulation structure (HFSS). The 2-slot microstrip patch antenna was then fabricated using microstrip coaxial probe feed technical .was calculated the return loss VSWR, real and imaginary impedance, radiation patter and gain results. The-10 dB impedance bandwidth of the proposed antenna is 9.06-13.86GHz , which is about 51.06% broader. The proposed antenna has an average gain of 6.3 dB and the peak is 8.239 dB at resonance frequency 9.42GHz. Compared with the original one , the average gain of the proposed antenna improve about 1.7 dB.