Propagation of current on bent wire antennas-an experimental study

The results of precise measurements of the driving point responses to a 200 ps input pulse of bent wire antennas of circular cross section mounted above a ground plane are presented. Transmission and reflection coefficients (plotted as functions of frequency to 3 GHz) describing the propagation and reflection of monochromatic current waves on the bent wires are inferred from the measurements. The results show that the current pulse reflected from a sharp bend (
r\theta \ll c\tau_{1}
), where
r
is the bend radius,
\theta
is the bend angle,
c
is the speed of light, and
\tau_{1}
is the pulse duration) is a compressed replica of the incident pulse, and that a current pulse propagating around a gradual bend (
r\theta \approx c\tau_{1}
) is continuously reflected from the whole length of the bend. The time domain measurements and the inferred frequency domain data give a clear physical picture of the mechanism of current propagation on bent-wire antennas.