Fig. 4 shows the return loss of microstrip patch antenna
array for both simulation and measurement. The simulation
result gives a return loss of -20.24 dB at operating
frequency 2.5GHz while the measurement result gives a
return loss of -22.22 dB at 2.67GHz. The flaws during the
fabrication process may lead to the shift of the operating
frequency of measurement result. The measured operating
frequency has shifted about 6.8% from the simulated
operating frequency.