Improvement of Folded Rhombic Antenna for Transient Electromagnetic-Field Radiator

A folded rhombic antenna as a broadband antenna for using a radiator instead of vertical coupling plane (VCP) specified in IEC 61000-4-2 was designed so that its dimensions were reduced as 1/2 smaller than the original antenna. Three antennas were built, and the complex antenna factors of their antennas were measured by the 3-antenna method. As a result, it was found that a usable frequency range of the prototype antennas is from 400 MHz to 4.5 GHz. Since the complex antenna factors of the antennas were within ±2 degrees in phase values in frequency range from 150 MHz to 4.6 GHz, the proposed antennas are applicable for the transient electromagnetic-field radiator.