Electrodynamic modeling of an ultra-wideband Lalezari radiator in the frequency domain

Electrodynamic modeling of an ultra-wideband Lalezari radiator — a combined radiator with horn and dipole properties — has been carried out in Ansys HFSS over a band with a frequency overlap ratio of 50. The radiator is matched to the feed line at a voltage standing wave ratio no worse than 3 in two operating sub-bands, from 0.14 to 0.59 and from 0.78 to 1.51, where is the operating frequency. The gain rises from minus 1.0 to 8.7 dB across the first sub-band and stays between 5.3 and 8.6 dB within the second, while the half-power beamwidth narrows with frequency from 69.7 to 24.9 degrees in one plane and from 35.3 to 26.0 degrees in the orthogonal one. The longitudinal coordinate of the phase centre lies within 1.84 and 2.06 for the two orthogonal pattern sections, where is the characteristic wavelength. Preserving its pattern shape and gain level between adjacent frequencies, the radiator introduces low distortion of the wideband signal waveform and can be used as an element of ultra-wideband antenna arrays operating with signals whose spectrum falls entirely within one of the sub-bands.