本論文提出應用於Ｘ(8-12 GHz)頻段之圓極化網格天線陣列設計，一般在使用線極化天線來傳輸或接收電磁波(特定頻率)的過程當中會受到多重路徑所產生的極化損耗之影響，因此為了提高傳輸訊號的品質與穩定度，須仰賴圓極化天線來做為傳輸或接收的工具。 在第二章提出天線陣列之設計中，陣列因子在每個天線單元功率平均分布時會有最大方向性，估算若利用傳輸線調整輸入天線功率使其平均分佈會造成之損耗，評估功率平均分布之可行性。此陣列天線以微帶線饋入方式實現圓極化網格天線陣列，其圓極化由兩貼片天線耦合產生相位相差90度、電場大小相同的輻射單元設計而成。網格天線陣列傳統上具有匹配電阻，本論文將電阻拔除改由天線取代，使用Arlon A250板材製作。 量測結果10 GHz串聯式兩個天線單元圓極化網格天線陣列量測頻寬為4%，軸比頻寬為0.5%，而增益為7.9 dBic。 10 GHz串聯式四個天線單元圓極化網格天線陣列量測頻寬為9.4%，軸比頻寬為0.9%，增益為11.9 dBic。 ;Design of series-fed circularly-polarized grid antenna arrays for X-band applications are presented in the thesis. Generally, when using linearly-polarized antennas, the transmission or receiving of the electromagnetic wave is often influenced by the polarization loss of multiple path. In order to increase quality and stability of transmitted signal, the circularly-polarized antenna is a reliable tool of transmission or reception. Design of the proposed antenna array is mainly described in the second chapter. The array factor in the antenna array will have a maximum value of directivity when all antennas are excited uniformly. To estimate the loss of the transmission line and adjust the input antenna power, uniform-distributed elements can be achieved. To evaluate the feasibility of the average power distribution. The antenna arrays achieves circularly-polarized grid antenna arrays by microstrip line feeding. The circular polarization is designed by two patch antennas being coupled to generate radiation unit with phase difference of 90 degrees and the same electric field magnitude. Traditionally, grid antenna array is designed with matching resistors. In the thesis, resistor is replaced by antenna that is designed on the Arlon 250A substrate. The measured bandwidth of the 10-GHz series-fed two-elements circularly-polarized grid antenna is 4%, the axial ratio bandwidth is 0.5%, and the gains is 7.9 dBic. The measured bandwidth of 10-GHz series-fed four-elements circularly-polarized grid antenna arrays are 9.4%, the axial ratio bandwidths are 0.9%, and the gains are 11.9 dBic.
