A disk-loaded thick cylindrical dipole antenna for validation of an EMC test site from 30 to 300 MHz

Abstract

We propose a new broad-band, short (80-cm-long) disk-loaded thick cylindrical dipole (DTCD) antenna for validation of an electromagnetic compatibility (EMC) test site for the frequency range between 30-300 MHz. In order to achieve broad-band characteristics, we have chosen a thick dipole as DTCD element. Disk loading has been applied to make this dipole shorter. To eliminate any ambiguity in balun characteristics, a commercially available hybrid junction is used as an antenna balun. Thus, the DTCD proposed in this paper is a very short, simple, and well-defined broad-band antenna that covers the frequency range between 30-300 MHz. The DTCD has an azimuthally symmetrical radiation pattern and, thus, is very well suited for the validation of an EMC test site. This paper presents the DTCD antenna characteristics such as input impedance, antenna gain, antenna factor, and classical site attenuation, which are calculated by use of the method of moments (MoM). These theoretical antenna factors and classical site attenuations of the DTCD are compared with experiments over the frequency range of 30-300 MHz. They agree with each other to within /spl plusmn/1 dB in antenna factor and to within /spl plusmn/2 dB in site attenuation. Our preliminary investigation indicates that an additional DTCD (25 cm long) can cover the frequency range of 300-1000 MHz. Therefore, only two DTCDs will be needed for very accurate calculable classical site attenuation values in order to validate an EMC test site for the entire frequency range between 30-1000 MHz.