應用於Ka頻段之電子式線性極化旋轉天線系統

Abstract

本論文實現一操作於Ka頻段之電子式線性極化旋轉天線系統(linear polarization rotator)，此系統可應用於5G無線通訊(5th generation wireless system)。 本論文將應用於5G通訊毫米波頻段之數位控制之線性極化旋轉晶片和線性雙極化天線整合在印刷電路板上面，並確保極化旋轉系統可以旋轉的功能。晶片可輸出兩個同相位大小分別為cos(τ)及sin(τ)的訊號，最後再將兩個訊號分別饋入雙極化天線的兩個端口，由雙極化天線負責將訊號輻射出去，其中τ為極化方向，極化方向由線性極化旋轉晶片控制，其中雙極化天線與線性極化旋轉晶片之間的輸出關係為一個轉換矩陣。 本論文印刷電路板均採用RO4003C在TSRI製作，在模擬階段時，電子式線性極化旋轉天線系統搭配晶片可實現16種切換狀態，每種狀態大約差11.25°，搭配第一版晶片在28GHz時均方根極化方向誤差為8.4°，軸比最佳為28.33 dB，最差為10.68 dB。搭配第二版晶片在28GHz時的均方根極化方向誤差為9.75°，軸比最佳為39.79 dB，最差為10.75 dB。 將量測數據進行調整後搭配第一顆晶片在28GHz時極化方向切換範圍為180°，均方根極化方向誤差為3.30°，軸比最佳為26.05 dB，最差為5.23 dB。第二顆晶片之量測在28GHz時極化方向切換範圍為180°，均方根極化方向誤差為4.23°，軸比最佳為23.26 dB，最差為3.8 dB。

This thesis implements an electronic linearly polarized rotating antenna system operating in the Ka frequency band, which can be applied to 5G wireless communications. This thesis integrates the digitally controlled linear polarization rotation chip and linear dual-polarization antenna on the printed circuit board, and ensures that the polarization rotation system can rotate 180°. The rotator chip provides two signals with equal phase and amplitude at cos(τ) and sin(τ). These two signals are fed into the dual polarization antenna. The dual-polarized antenna radiates the signal, where τ is the polarization direction, and the polarization direction is controlled by the linearly polarized rotating chip.The output relationship between the dual-polarized antenna and the linearly polarized rotating chip is a transformation matrix. The printed circuit boards in this paper uses Rogers RO4003C substrate. At the simulation stage of this thesis, the electronic linearly polarized rotating antenna system can realize a total of 16 switching states, and each state has a difference of about 11.25°. With the first version chip in RMS,,the polarization direction error is 8.4°, the best axial ratio is 28.33 dB and the worst axial ratio is 10.68 dB. With the second version chip in RMS, the polarization direction error is 9.75°, the best axial ratio is 39.79dB and the worst axial ratio is 10.75 dB. After adjusting the measurement data, the polarization direction switching range of the first version chip at 28GHz is 180°, the RMS polarization direction error is 3.30°, the best AR is 26.05 dB and the worst AR is 5.23 dB. With second version chip at 28GHz, the measured rotation range is 180°, the RMS polarization direction error is 4.23°, the best AR is 23.26 dB and the worst AR is 3.8 dB.