  This research work focuses on the design and simulation of a planar dipole
antenna for 1800MHZ Band for Global System Mobile GSM application using
Computer Software Technology CST studio software. The antenna is structured on
a fire resistance FR4 substrate with a relative constant of 4.3 S/m. Two types
of feeding configuration are designed to feed the antenna in order to match 50
ohm transmission lines which are via-hole integrated balun and quarter
wavelength open stub. The via-hole is capable to provide maximum return loss of
25dB, bandwidth of 18.4 percent and the voltage standing wave ratio (VSWR) of
1.116 V at optimum dimension of length 59mm and width 4mm, the bandwidth is
improved 25 percent to 30 percent by extending the width of the antenna 8 mm to
10 mm followed by deterioration of return loss value to 15dB. While the open
stub at length of 67 mm, the width of 6 mm and height 1.6mm will provide max
return loss of 47.88dB and bandwidth of 17 percent with VSWR 1.008 less than 2.
The way that the antenna substrate has influenced the performance of the
antenna. The lower relative constant will result in the higher return lows,
narrower bandwidth and better radiation pattern in trade-off the resonant
length Via-hole and then the quarter wave open stub are most convenient for
practical implementation.
