Experiments for element spacing on a 2 by 2 patch antenna array

This paper presents the comparison between the calculated and measured radiation patterns of a two by two patch antenna array with three different element spacings. The optimum element spacing for a specific grating lobe level is obtained by the proposed optimization process. The optimization goal is to obtain narrowest steering beams with a desirable grating lobe level. The lager element spacing lead to narrower beam width. In this paper, the desirable grating lobe is either less than -10dB or at -3dB levels and the main lobe is not less than -3dB. The patch antenna array is fabricated and measured in an anechoic chamber. The measured results are compared with the calculated ones. The measured and calculated patterns are similar at main lobe but both patterns are different around grating lobe area.