R3765CH Network Analyzer. The measured return loss and radiation pattern results have been given, and they are in good agreement with the simulated ones by CST. Figure 3 shows the measured and simulated return loss characteristics for the proposed antenna.
The impedance bandwidth is defined as reflection coefficient less than ร15 dB. The center frequency and impedance bandwidth of simulated results in the proposed antenna are 2450 and 250 MHz, respectively. The corresponding data of measured results are 2470 and 200 MHz, respectively. Both the return loss of the simulation and the measurement are less than ร15 dB in the frequency band from 2400 to 2480 MHz. The proposed antenna really meets the requirements in the impedance performances for the WLAN 2400 MHz applications.
The radiation patterns of the proposed array antenna by simulated and measured are plotted in Figures 4 and5, respectively. From these figures, one sees that the half-power beamwidth of E-plane is about 13.55 , and the maximum gain is 15.90 dBi in the range from 2400 to 2480 MHz. The half-power beamwidth of H-plane is about 59.88 , and the maximum gain is 15.85 dBi in the range from 2400 to 2480 MHz. Thus, the microwave antenna array has wider beamwidth and high gain good to meet the performance requirements of WLAN network.
4. Conclusions
A new type of array antenna has been designed, fabricated, and measured. The array antenna has been verified in good agreement by measurement and simulation. Measurement shows that the antenna gain is 15.9 dBi for 2480 MHz band (E-plane) and 15.85 dBi for 2480 MHz band (H-plane), respectively. In the range of WLAN band from 2400 to 2480 MHz, the return loss of the microstrip array antenna is less than ร15 dB, and the maximum gain is 15.90 dBi, which greatly improves the gain than that of the previous literatures. The antenna dimension is 400 ร 98 ร 0.7 mm 3 . Both characteristics of the broad band and large gain make the proposed antenna very suitable for the WLAN application.