operating frequency bands in X-Z plane as illustrated in Fig.
9(a). However, the cross polarization pattern in X-Z plane
expands due to the higher transverse magnetic mode order of
the antenna, as extending the frequency. As depicted in Fig.
9(b), the radiation patterns in Y -Z plane are bidirectional
patterns at all operating frequencies. It can be noticed that the
magnitude of resonant frequency 2.45 GHz is at 0 and 180
degree, while the magnitude of other resonant frequencies 3.5
GHz and 5.25 GHz occur at 210 and 330 degree resulting in
the higher transverse magnetic mode order of the antenna, as
extending the frequency.