respectively. Fig. 6 shows the variation of the efficiency of the
proposed antenna with the frequency. The efficiency decreases
with the increase of the frequency till 3.8 GHz. After that the
efficiency gradually increases. The antenna attains maximum
efficiency at 2.0 GHz (86.87%) and minimum efficiency at 3.8
GHz (63.68%). The efficiencies at 2.4 GHz and 5.8 GHz are
88.61% and 76.32% respectively.
The E-plane and H-plane radiation pattern from the IE3D
simulation [10] of the C-shaped monopole antenna at 2.4 and
5.8 GHz is shown in the Fig. 7 and Fig . 8 respectively. It can
be observed that E-plane radiation pattern is of the shape 8 in
the two frequencies. At 5.8 GHz the E-plane radiation pattern
is tilted towards the right. E-plane radiation pattern has
maximum directivity at 0° and -180° at 2.4 and 5.8 GHz. The
H-plane radiation pattern on the other hand is purely omnidirectional
pattern at the two frequencies i.e. at 2.4 and 5.8
GHz. Hence, this C-shaped monopole antenna demonstrates a
consistent radiation pattern in the desired band of frequencies.