The proposed antenna is chosen to generate two or
more resonant bands for achieving ultra wide bandwidth.
The width of the CPW feed line is fixed at 3.0 mm to
achieve 50Ω characteristic impedance. Since the radiator
is surrounded by a metal ground plane for reducing the
antenna area, the small gap between the radiator and the
ground plane is a major factor to cause over strong
capacitive coupling. The horizontal feed section (x-axis)
is separated from the ground by a gap of 0.4 mm (see
Fig. 1).