The Kootwijk VLF Antenna: A Numerical Model

The first documented numerical modelling of the historical Kootwijk VLF antenna is presented. Simulations using NEC-5 show the operation of this electrically short antenna at resonance. Simulation results agree with theoretical expectations but indicate the radiation efficiency — although comparable with other antenna systems of the same historical era — is lower than it potentially could be. Potential causes of the low radiation efficiency are discussed. This modelling also provides further validation of the relatively new NEC-5 simulation software on a complex antenna design having substantially different wire diameters at acute angles.