A Patch-Splitting Base Station Dipole Antenna With Wideband Electromagnetic Transparency

Traditional multi-band shared-aperture base station antenna arrays often suffer from limited electromagnetic (EM) transparency bandwidth, leading to difficulties in cross-band scattering suppression. This letter explores EM transparency from the perspective of the spatial power manipulation of dominant scattering modes. It is found that the induced scattering currents on the radiating structure of a low-band (LB) antenna will exhibit naturally minimal influence on the high-band (HB) antenna when the main beams of scattering modes deviate from those of the HB radiation patterns. To realize wideband EM transparency, we propose a novel patch-splitting strategy for the design of dipole antennas. Ring-shaped slots are first etched onto the LB dipole arms to achieve beam-steering of the scattering characteristic modes. Then, cross-shaped slots are introduced to reduce the magnitude of HB-induced scattering currents. A dual-band shared-aperture interleaved antenna array, consisting of a 2×2 HB antenna array (1.65∼2.85 GHz, 53.3%) and an LB patch-splitting dipole (0.69∼0.96 GHz, 32.7%), is designed and fabricated. Measurement results confirm that the HB radiation patterns remain undistorted in the presence of the LB antenna, which well demonstrates the effectiveness of the presented approach.