本論文提出應用於毫米波系統之雙線饋入式圓極化網格天線陣列設計。在設計中主要是以兩個線極化網格天線陣列組合成雙線饋入式圓極化網格天線陣列。在第五代行動通訊中將使用較高的頻段，高頻傳播時損耗較大，因此以天線陣列的形式提高增益應是合理可行的做法。本論文將設計韓國第五代行動通訊高頻段26.5GHz-28.9GHz。
以往相關圓極化天線設計大都以不規則的貼片形狀結構，而其參數大多都耦合在一起，微調不易，且在毫米波頻段天線尺寸縮小，製程上的誤差會嚴重影響到天線特性，因此提出一種設計相對簡單的天線陣列設計。設計出兩個線極化天線陣列，天線擺放成正交，並以功率分配器給予相同能量大小以及90度相位差，使天線具有圓極化特性。
量測結果雙線饋入式圓極化網格天線量測頻寬20.9%，軸比頻寬9.9%，增益為5.4dBic。雙線饋入式圓極化網格天線陣列量測頻寬18.1%，軸比頻寬2%(28.01-28.58 GHz)和1.2%(27.39-27.74GHz)，增益為9.79dBic。

A design of circularly polarized grid antenna array with double series-fed configuration for millimeter-wave applications will be proposed in the thesis. In the design, two linearly-polarized grid antenna arrays are combined to form a circularly polarized grid antenna array with double series-fed configuration. In the fifth-generation wireless systems, a higher frequency band will be used. Due to the path loss will be larger in high-frequency propagation, the antenna gain is often increased in the form of an antenna array. The proposed design will accommodate the frequency band 26.5GHz-28.9GHz of the fifth-generation wireless systems, mainly used in South Korea.
In the past, the design of circularly polarized antennas were mostly irregular patch-shaped, and most of their parameters were coupled together. It is not easy to fine-tune these parameters. The size of the antenna is reduced in the millimeter wave. The error in the manufacturing process will seriously affect the antenna characteristics, so this paper proposed a relatively simple antenna array design. First, we designed two linearly polarized antenna arrays, and then arranged the antennas in orthogonal directions. We fed the arrays with the same amplitude and 90 degree phase difference by using a power divider, so that the array has circular polarization characteristics.
The measured bandwidth of the circularly polarized grid antenna array with double series-fed configuration is 20.9%, the axial ratio bandwidth is 9.9%, and the gain is 5.4dBic. The measured bandwidth of the circularly polarized grid antenna array with double series-fed configuration is 18.1%, the axial ratio bandwidth is 2%,1.2%, and the gain is 9.79 dBic.

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