On the Broadband Reflector-Backed Dipole Antennas With Wide Beamwidth for the EMC Tests of Large Equipment Above 1 GHz

In this paper, we introduce the concept that the antenna beamwidths should match the physical dimensions of equipment under test when performing the radiated emission and radiated susceptibility experiments, and for the first time, we propose the usage of reflector-backed dipole antennas (RBDAs). The coverage requirements are categorized into several groups according to the typical dimensions of several large platforms for the horizontal and vertical polarizations. The directivities and achievable electric field strengths of RBDAs are estimated and discussed. An approximate current distribution is proposed for the RBDAs with an infinite reflector, which can predict the radiation patterns for a given dimension and facilitate the design procedure. In addition, the usage of nonplanar dipole elements is briefly introduced to increase the E-plane beamwidth. The array techniques are utilized to reduce the beamwidth flexibly in the E- or H-plane for the EUTs with a large length-to-height ratio. Design examples are presented and numerically evaluated to verify the proposed solutions.