在本文中探討應用於WLAN頻段的雙頻迴圈天線，此天線可以很容易印刷在基板上並由一組雙頻的平衡饋入電路做輸入。輻射體主要是由兩個頻段的全波長迴圈天線作疊接的結合，加上一組利用兩輸出端相位差為180度的特性來達成平衡饋入的效果。而雙頻的路徑是由一個DGS (defected ground structure) 和環形諧振器來構成。
論文中使用HFSS的模擬軟體來分析並和測量的數據比較。在VSWR小於2，頻率2.45GHZ所量測到的單頻印刷迴圈天線頻寬為420MHz且天線增益為1.38dB。而頻率5.2GHz所量測到的單頻印刷迴圈天線頻寬1000MHz且天線增益為0.64dB。在雙頻2.45/5.2GHZ所量測到的結果，在頻寬上分別是400和120MHz，在增益上分別為 2.3和1.7dB。將模擬和量測數據加以比較得到相當吻合的結果。

In thesis, In WLAN band the dual-band loop antenna is proposed. The dual-band loop antenna is fed by dual-band balanced feeding circuit and can be easily formed by printing on both sides of a dielectric substrate. The radiated object mainly consists of shunt-connecting both one-wavelength loop antenna for 2.45 and 5.2GHz, individually. The balanced feeding used the transition which is to introduce 180 degrees of phase delay in the two outputs of microstrip lines. By the way, we achieved the dual-band resonator paths by DGS and ring resonator.
Both simulation and measured data are pretty matched and compared with HFSS simulator. It has been shown that loop antenna for VSWR 2 can be achieved. According to the measured results, The printed loop antenna achieves gain for 2.45GHz band to be about 1.38dB with 420MHz bandwidth and the 5.2GHz loop antenna has a gain of 0.64 dB with a 1000MHz bandwidth, respectively. The dual-band printed loop antenna has gain of 2.3 dB with a 400MHz bandwidth and gain of 1.7 dB with a 120MHz bandwidth for 2.45/5.2GHz, respectively. Both simulation and measured results are matched.

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