A Kind of 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 biconic 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 along the only tangential direction of the envelope in the conductor axis, thecurrent distributions are calculated by means of the moment method. The triangular functions are chosen as the expansion functions and weight functions. An example of the broadband dipole antenna is shown and radiation patterns, gain, input impedance are computed. Also VSWR is computed and measured. It is found that the antennas studied have satisfying broadband characteristics.