Then I studied all antenna parameters by increasing the
height of the substrate of structure D to 2mm and keeping
whole remaining structure same as it is with h=0.8mm. There
is further improvement in BW and rad. efficiency, while all
other parameters are almost same with negligible change as
compared to those of cylindrically cut DR brick loaded
antenna with h=0.8mm. Here 21.7% (1.59 GHz) BW is
achieved with H=5.85mm, but 117 MHz (from 8 GHz to 8.117
GHz) portion is outside of C-band. So to bring it inside the Cband,
we decreased height of the DR continuously and for
H=3.5mm, we got 10dB impedance BW of the plot inside the
C-band. Here achieved BW is 19.4% (1.36GHz) as shown in
Fig. 24, while 99.3% rad. efficiency is achieved.