主動式電子掃瞄系統前瞻關鍵技術發展

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Date

2011-12-01

Authors

周錫增
鄧俊宏
蔡政翰
黃能添
許恆通
甘堯江

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Publisher

行政院國家科學委員會

Abstract

本計畫主要是協助中科院發展新一代之陣列雷達系統,尤其是主動式電子 掃描系統,針對RF 系統和數位訊號之處理,相關研究構建了前瞻關鍵技術的 核心。整體計畫由三大區塊建構而成,包括了陣列天線設計,高頻RF 接收機 之設計和陣列信號數位波之天線元素。計畫中將雷達應用中利用四個象限之 陣列天線來形成Sum 及Difference 波束,並以主動雷達系統架構實現智慧型 天線中switch-beam 之概念,以產生具高方向性與低干擾之發射波束,進而優 化了回射波在Sum 和Difference 的特性。在系統之實際構裝上兼顧了系統的 擴充性和國內產業的優勢,故在天線設計方面採模組化的方式建構,以2n 之 元素(n=3)建構於同一模組上,並利用了IC 製程之多層模板機構來建置相移 器。本計畫為多年期計畫之第三年,將針對前一年計畫執行之成果進行延續 性之研究。本年度之工作重點在於前端系統中所有主動元件關鍵零組件之電 路設計驗證、製造及功能性測試以及陣列天線單元間耦合效應分析,另外為 了考慮未來較多單元系統在電性功能及構裝上的擴充性,有關天線單元以及 後端電路間進一步的整合亦將一併探討。有關在高頻操作下電磁波之可能造 成耦合與輻射效應,包含天線單元彼此間及天線與後端電路之耦合亦將透過 電磁分析模擬技術加以分析,最後將利用分析結果對系統端進行佈局之最佳 化設計。 此外,在波束形成方面,本計畫將研究一種低複雜度之混合型智慧天線系 統,使其具有方向性次陣列與低數量之數位波束合成器可執行干擾消除與想 要信號之偵測。對於傳統之智慧型天線系統為由全方向之子天線所組成,此 系統為利用全數量之數位波束合成器進行干擾消除與最佳性能之偵測。然 而,本研究計畫將會充份利用方向性次陣列之低旁波束抑制干擾信號,並結 合少數量之次陣列接收信號執行數位波束合成器,上述類比與數位兩種波束 合成器之結合將可提供有效率之干擾消除能力。
Smart antenna system is a complete system consisting of antenna, RF analog T/R module, digital signal processing unit and post adaptive beam forming unit. Since the radiation pattern of the smart antenna system can easily be adjusted through proper modifications on the weighting functions to respond to environmental changes almost immediately, such system has the advantages of interference suppression, communication quality improvement and increase of channel capacity. Therefore, it has been widely applied in advanced phased array radar systems. In general, the complexity of smart antenna system depends strongly on system applications. For advanced wireless communication systems, phased array antenna structure is usually adopted with large number of T/R modules involved. The most challenging issue of this arrangement lies in the complexity of system integration caused by the number of T/R modules involved which in turn increases drastically the DC power consumption required. The main purpose of this proposed project is the design and development of Ku-band switched-beam phased array radar systems. This is the second year of the multi-year project with the main focus on the MMIC designs of active components in the T/R and the accurate assessment of all the possible electromagnetic couplings among antenna elements while integrated into compact modules. The main technology development will cover the designs of Ku-band power amplifier, Ku-band low noise amplifier, Ku-band switches, Ku-band phase shifters and the feasibility study of integration of the complete T/R onto single chip. Meanwhile, to guarantee the proper functionality of the whole system, electromagnetic couplings among the antenna elements have to be accurately characterized. Full wave electromagnetic simulation in conjunction with the hybridization method will be applied to resolve this issue. In addition, a low complexity hybrid smart antenna system with directional subarrays and reduced-size digital beamformer is proposed to suppress the undesired interferences and detect the signal-of-interest (SOI). For the conventional smart antenna system with omni-directional elements, it utilizes the full-size digital beamformer to suppress interference and obtain the optimum performance. However, the proposal of hybrid smart antenna system with directional subarrays can suppress the interferences via the lower sidelobe of the beampattern of subarrays and the digital beamforming capacities using the smaller number of the received signals. Thus, the proposed hybrid smart antenna can simultaneously provide the analog and digital beamformer to suppress jamming interference.

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