EMD from negative corona discharge

In this paper, the electromagnetic (EM) wave radiated from negative corona discharge has been investigated through a series experiments in which the discharge occurs in a set of needle-plate electrode in a closed loop circuit. The polarization pattern and orientation diagram under some different frequency have been presented and the results verify the assumption that the EM wave radiated from negative corona discharge in a closed loop circuit contains two components: one is from the equivalent short dipole antenna and the other from the equivalent little circular loop antenna. Experiment results will be useful for estimating the electromagnetic disturbance (EMD) from corona discharge.