Dipole antenna with broadband characteristics

The broadband dipole antenna presented is a rotationally symmetric structure consisting of conductor wire whose surface shape is smoothly joined by bi-conic section, spherical stage and cylinder dipole each other in series in the direction of antenna axis, fed by a coaxial cable with impedance of 50 Ω at center. Assuming that the equivalent current on the surface is variable only along the tangential direction of the envelope in the conductor axis, the current distributions are calculated by means of the moment method. The triangular functions are chosen as the expansion functions and weight functions. The radiation patterns, gain, input impedance and VSWR (voltage standing-wave ratio) for an example of the broadband dipole antenna are computed. It is found that the antennas studied have satisfactory broadband characteristics.