Design and Analysis of Non-Uniformly Spaced Dipole Array Antenna

Dipole antenna array is designed at operating frequency of 450MHz using FR4 substrate. Uniform circularly polarized (UCP) and non-uniform circularly polarized (NUCP) dipole arrays are designed. NUCP array is achieved by placing antenna elements at unequal distance from the reference element. Low side lobe level is necessary to reduce interference with other frequencies in the band which is achieved in case of NUCP array compared UCP array. The simulation is carried out using EM flow solver HFSS. The simulation results indicate that there is a reduction in the side lobe level for the 1×7 NUCP array as compared to UCP array. To enhance the gain of the dipole array dielectric lens is used as the secondary radiator which also acts as a radome to protect the array. The maximum gain achieved is 1.59dB with lens. Return loss less than -15dB is achieved in all cases. Axial ratio less than 3dB achieved for circular polarized arrays. The designed NUCP array with lens can be used in SAR (synthetic aperture radar) applications.