This paper deals with an approach for improving the resolution of radar by increasing the equivalent radar antenna aperture through motion of targets and decreasing its equivalent beamwidth.

Simulation results show that in order to get satisfied thinned arrays the peak sidelobe level(PSL) and the beamwidth must be considered together.

The technique is studied by making use of EM simulation and experimentation for adjusting the beamwidth of -10 dB and reducing the VSWR and axial ratio for circ.

The distortion in a horn simply,and an example of a constant directivity horn are discussed,which gives an actual measured polar response,beam width at horizontal & vertical axis,the relation among directivity factor,and directivity index & frequency.