The C-shaped monopole antenna is printed on the FR4
substrate of relative permitivity 4.4 and the thickness 1.6 mm.
as shown in the Fig. 1. The shape of the antenna element is like
a C-shape without the conductor backed ground plane. A 50Ohm
microstrip line is used for the excitation. The strip width
of the C-shaped monopole antenna is 2 mm, the same as that of
the width of the microstrip line. The remaining design
parameters are given in the Fig. I.