A Compact Broadband Monopole Tapered Slot Antenna With High Field Uniformity for Vehicle EMC Test From 20 to 220 MHz

A compact broadband monopole tapered slot antenna (MTSA) for vehicle electromagnetic compatibility tests in the semianechoic chambers (SAC) is proposed and investigated. The proposed MTSA takes the metal ground of the SAC as part of an antenna. With the mirroring effect of the ground plate in the SAC, the proposed MTSA acts as a conventional tapered slot antenna (TSA) but with only a half size of the conventional TSA, and also avoids the adverse effect of the ground reflections on the field uniformity effectively. Moreover, the MTSA has a slot on its flaring plate that reduces its weight by 30%. Both the simulated and the measured results show that the proposed MTSA achieves a standing wave ratio below 2:1 from 20 to 220 MHz, and a good uniformity, with radial uniformity better than 3 dB, transverse uniformity better than 4 dB. The simulated gains are from 6 to 13.5 dBi with radiation efficiencies over 90% across almost the entire bandwidth.