| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 95 === For the practical applications of wireless local area network (WLAN), the size of dual-band antennas, which can transmit and receive electromagnetic radiation simultaneously, is required to be small. To meet the requirement, we proposed an S-shaped planar dual-band monopole antenna which is suitable for 2.4 and 5GHz WLAN systems according to the IEEE 802.11 standards. The proposed antenna had a resonent path for the excitation of the two modes. One mode corresponded to a λ/4 radiator of 2.45 GHz and the other, 3λ/4 radiator of 5.25 GHz. To determine proper design parameters, the antenna was first analyzed by using the HFSS software. The simulation also demonstrated that the width of the ground imposed more influence on the antenna than the length of the ground did. The S-shaped antennas were realized on FR4 (εr4.4 ) and Al2O3(εr=9.8 ) substrates, respectively. The measured 10 dB bandwidths of the FR4 antenna were 300 MHz centered at 2.3 GHz and 1075 MHz centered at 5.4 GHz. And the measured 10 dB bandwidths of the Al2O3 antenna were 400 MHz centered at 2.35 GHz and 1000 MHz centered at 5.2 GHz. The gains of the FR4 antenna were 2.3-3.35 dBi for the 2.4 GHz band and 1.73-2.97 dBi for the 5.25 GHz band. And the gains of the Al2O3 antenna were 2-2.76 dBi for the 2.4 GHz band and 0.15-1.55 dBi for the 5.25 GHz band. The measured results agreed with the simulations. For the far-field radiation, the measured and simulated results were close on the x-y plane and a little different on the x-z and y-z planes.
|
|---|
