First, we explain our method for the calibration of LPDA.
The experimental setup is schematically shown in Fig. 1. All
the measurements were made on the ground plane in a semianechoic
camber. LPDA is used as an AUT. The antenna is
set perpendicularly to the ground plane with the variable
position from 1 m to 5 m high above it.
The reflection coefficient s11(Ȧ) is measured by a VNA in
frequency- domain, and it is transformed to the
corresponding time-domain reflection coefficient s11(t). s11(t)
is calculated by the inverse Fourier transform F-1(Ȧ) with the
Hamming frequency-domain window W(Ȧ) as given b