應用於5G行動通訊之雙極化槽孔天線之設計與實作

Design and Implement of a Dual-Polarized Aperture Antenna for Pre-5G Mobile Communication

劉詩亭(Shih-Ting Liu)

指導教授 ： 林怡成

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.10056

摘要

本論文針對瑞雷衰落環境下，分集天線系統之表現進行數據探討，包含考慮來向波統計特性之相關係數、平均有效增益、以及有效分集增益。藉由分析ㄧ對半波長偶極天線，了解極化分集和天線距離對其表現之影響，進而研究兩對半波長偶極天線之分集表現。結果顯示當一天線具有極化分集特性時，其系統表現較不受天線間距離的影響。
本論文接著提出ㄧ針對未來第五代行動通訊發展、作用於30GHz毫米波頻段，適用於多輸入多輸出系統之雙埠雙極化之寬頻槽孔天線。其具有結合漸變縫隙以及方型開槽結構之合成槽孔和背腔式設計，使此天線有小型、寬頻、單向性輻射、極化分集及場形分集等良好特性。所設計天線之特性經過實驗證實在以10dB為基準的返回損失、隔離度和正上方正負25度內之輻射場型上都與數值模擬結果有良好的吻合度，其埠與埠隔離度更是優於 26dB。其平面式設計適合用於低成本之平面印刷式電路板製成，另其利用微帶線以及共平面波導做為與外部電路連結，亦可輕易與射頻電路做整合。本論文進ㄧ步利用該雙埠天線，提出一天線陣列架構，量測結果顯示其擁有18dB之埠與埠隔離度。最後，本論文利用前述分集系統表現佐證所提出之雙埠雙極化之超寬頻天線於多輸入多輸出系統上具有良好的增益，天線陣列亦如是。

關鍵字

毫米波 ； 單向性輻射 ； 極化分集 ； 分集表現 ； 封包相關係數 ； 平均有效增益 ； 有效分集增益 ； 5G ； 多輸入多輸出

並列摘要

In this thesis, antenna diversity performance is discussed in Rayleigh fading environment, including the envelope correlation coefficient, the mean effective gain and the effective diversity gain under statistical arrival angles of the incident waves. By analyzing a pair of half-wavelength dipole antennas, the influences of polarization and space diversity to the diversity performance are investigated; then extend to the case of two-pair dipole arrays. The results show that when an antenna has the characteristic of polarization diversity, its diversity performances is less sensitive to the spacing between dipole pair.
This thesis presents a dual-port dual-polarized wideband aperture antenna operating at millimeter wave frequency 30 GHz for multiple-input multiple-output (MIMO) system applications and pre-5th generation mobile communication systems. With tapered aperture hybrid structure and backed cavity design, the antenna achieves wideband polarization diversity gain with unidirectional broadside radiation. Verified by experimental results, the antenna performance coincide with numerical results, including of 10dB return loss, isolation, and radiation patterns between +/- 25 degrees from zenith direction. The proposed antenna also possesses high port-to-port isolation better than 26dB. Its planar design indicates the suitability for the low-cost PCB manufacturing. And the out-fed design with the microstrip-line or coplanar waveguide, eases the integration with RF circuits. This thesis further proposes a 2 by 2 array to investigate the coupling effects on the port impedance, isolation and radiation patterns. The results show that it has good port-to-port isolation better than 18 dB. In the end, the diversity system performances of the proposed antenna are calculated to confirm its high effective diversity gain for MIMO system.

並列關鍵字

millimeter wave ； unidirectional radiation ； polarization diversity ； diversity performance ； envelope correlation coefficient ； mean effective gain ； effective diversity gain ； 5G ； MIMO

參考文獻

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