Radome enclosed antenna proximal lobe distortion based on near-field pattern

Near-field and far-field pattern of radome enclosed antenna are simulated by FEKO, and the reason of far-field pattern proximal lobe distortion is analyzed based on near-field pattern. Equivalent near-field technique is applied in simulation process, which is precise and effective. Near-field pattern indicates three effect result in proximal lobe lifting: firstly, radome top area diffracts electromagnetic wave obviously, and wavefront bifurcates; secondly, metalic nose tip is excitated to engender surface current which causes secondary radiation; thirdly, partial electromagnetic wave reflects and then transmits through radome top area, thus reflection-transmission wave energy superposes in proximal lobe direction. Radome design is improved based on three effects mentioned above, and proximal lobe level of radome enclosed antenna is degraded obviously. Near-field pattern method reveals the relationship between radome local details and far field pattern, and is very valuable in radome electronic performance optimization.