Mitigating Radiation Pattern Ripples Due to Edge Diffraction in Central Element of a Large Array Using Top Hat Loaded High Impedance Surface

Edge diffraction has been identified as one of the potential causes that downgrade the radiation characteristics in an antenna array, when the ground size is increased to incorporate multiple elements. A study has been conducted in this work, to identify the likely sources of the edge-diffracted waves, which create ripples in the radiation pattern of a centrally placed antenna element in an array. Edge-traveling surface waves, which contribute to this performance degradation has been mitigated using a top hat loaded high impedance surface (HIS). The radiation characteristics of the resultant HIS incorporated structure exhibited a smoother, ripple-free radiation pattern.