Suppression of postpulse oscillations in active bow-tie antennas

Abstract

Subject and Purpose. This theoretical and experimental research is devoted to peculiarities of the ultra-wide bandwidth (UWB) pulse radiation from active bow-tie dipoles. The focus is on the relationship between the amplitude-time dependences of electromagnetic fields produced by active UWB pulsed antennas and the configuration of the conductive components for temporally short (less than 0.5 ns), ultra-wide-bandwidth pulse radiation. Methods and Methodology. Analysis of the radiator geometry action on the emitted pulse parameters is performed by numerical simulation with the use of the finite-difference time-domain (FDTD) method. The experiment involves specially made, variously shaped bow-tie radiators tested with different resistive loadings in radiation mode. The numerically simulated characteristic curves of the radiated field amplitude shape versus radiator geometry are confirmed by experiment. Radiation field parameters versus load resistance are experimentally studied, too. Results. Conditions for the effective pulse radiation with a largest-possible pulse amplitude have been determined, the post-pulse oscillation amplitude and duration reduced to a minimum. Conclusion. It has been shown that the resistive loading in the excitation area significantly reduces amplitudes and durations of post-pulse oscillations in signals radiated by active dipole antennas.