Modeling of Broadband Shortwave Antennas With Numerical Electromagnetics Code

Abstract: Antenna designers always search for ways to improve existing designs or introduce novel designs in order to achieve desirable antenna characteristics. The linear wire dipole antennas are very important in communication systems at all frequency bands. These antennas are used by typically military, navigation and surveillance purposes. The broadband antenna which was built in the year of 1950 and was working efficiently for over half a century, some problems such as inefficient radiation, imperfect feeding point impedance and high voltage standing wave ratio (VSWR) were discovered when sending information via this broadband antenna in the operating frequency range of 9-11 MHz. In order to meet the proper specifications antenna is modeled before implementing physically. The Numerical Electromagnetics Code (NEC-4) is used to simulate the antenna models and results are analyzed by using MATLAB. The results of this study indicate that the antenna models achieve more than 70% of radiation efficiency including practical considerations such as ground parameters, material of the antenna and height of the antenna, impedance matching and low VSWR.