Design of Non-Uniform Circularly Polarized Dipole Antenna Array for P-Band Applications

A Non-Uniform Circularly Polarized (NUCP) dipole antenna array is designed for P-Band applications operating at a resonant frequency 450MHz. Circular Polarization (CP) is achieved by placing four dipoles with appropriate phase excitation. Non-uniform array here refers to non-uniform inter-element spacing between the elements. For performance comparison, 1x4 and 1x5 uniform circular polarized (UCP) arrays are designed. FR4 substrate with dielectric constant 4.4 is used for the antenna design. The simulation is carried out using EM flow solver HFSS. The simulation results indicate that there is a reduction in the sidelobe level (SLL) for the 1x5 NUCP array. Further to enhance the gain of the dipole array, a dielectric lens of polypropylene material is used and excited with UCP array and NUCP array. It is observed that the maximum gain enhancement of 1.54dB is achieved with lens. All the designed models exhibit a return loss less than -15dB and axial ratio of less than 3dB. The designed NUCP dipole antenna array with dielectric lens could be used for P-band applications such as synthetic aperture radar (SAR) imaging.