2016-08-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/712222摘要：本計畫發展反射陣列天線技術、尤其是具備金屬結構之反射天線單元，來提升高增益天線性能。本計畫緣由於高頻微波的傳播會產生相當高的能量損耗，此能量衰減發生天線輻射電波在空氣中傳播的損耗及在設計天線時實現於介電質基板所產生的損耗，當頻率愈高時、此損耗愈加嚴重，最終對於天線及通訊的使用產生無法克服的問題。 本計畫所欲發展的天線技術根植於過去幾年的研究成果，使得前瞻的天線技術得以有相當的機會來實現，在科技部的補助下，本團隊發展了全金屬結構之反射單元來使得天線之輻射效率能有效保持，最佳可超過90%以上(指在Ku-band以上)，此種特性決優於介電基板形式的反射陣列天線，而進一步擺脫了傳統介電質的PCB板來實施，尤其在高頻時，天線能量的損耗拘限了天線的使用，包括天線的體積過大來補償增益之不足、產生過度狹窄的波束等問題，本計畫藉由提升能量的效率而進一步實現體積縮小的目標與提升天線效能。 反射陣列天線的發展瓶頸在於無一個可靠的數學模式，因此其設計均需要使用全波數值電磁模擬來計算其輻射波形，此全波數值模擬需要花費相當大的時間，因此 反射陣列素來應用於波束聚焦之應用，無法發揮其優勢。在近年的研究中，本團隊克服了此項侷限，發展了有效的天線單元及其數學模型，可以利用快速的分析反射陣列天線的輻射特性，並且應用於Ku-band之天線設計中。 在本計畫中，我們將深入探討反射陣列天線的前瞻應用，以此金屬單元為基礎，發展數項反射陣列天線的前瞻技術，包括在頻域(frequency domain)及時域(time domain)的各項技術，這些項目包括雙頻反射陣列天線的技術；單頻多波束的反射陣列天線技術；雙頻多波束的反射陣列天線技術等，技術重點仍然至於全金屬的陣列結構，尤其應用於Ku-Ka雙頻段在衛星通訊的應用，希望克服PCB之技術瓶頸、而產生low profile的天線型態。本計畫為基礎技術研究，目標在發展各項基本理論、應用技術實現全金屬反射陣列天線的各項功能及了解其個像特性。尤其本計畫的實施可對應於台灣的精密加工等優勢，可有效支援，此亦為台灣之優勢，其應用將會成為一個嶄新的局面，本計畫之提出即是基於這些理念。 <br> Abstract: The investigation of reflectarray antennas is proposed in this project, where the fundamental theory and application technologies are developed. This work is motivated by the increasing applications of higher frequencies, where the propagation loss in the air and in the dielectric substrates is very severe with respect to the increase in the frequencies. A potential application is in the DTV reception, where reflector antennas are popular used to enhance the efficiency, which is relatively bulky. The reflectarray may provide low profile and has the flexibility to optimize the radiation. This work is based on our previous achievement in the related technology. In particular, we have developed the reflecting elements with metal structures which may provide high energy efficiency, and are particularly useful in the applications of high frequencies since the weights can be dramatically reduced. This energy efficiency may overcome the conventional applications of PCB based technology to realize reflectarray or phased array antennas, where energy loss of many dB may occur. It is noted that the energy loss will result in oversized antennas to compensate the lost gain, and result in over-narrow radiation beam. It will in turn loss the coverage in the cellular communication, or loss the beamwidth in the communication with satellite. Based on our previous achievement of metal elements as well as the mathematic model to simulate the radiation, time-consuming full wave simulation can be avoided. As a result, many technologies relying on the heavy simulation can be now developed. In this project, we will develop the technologies of dual-band and multi-beam reflectarray antennas in both time and frequency domain. We will develop the fundamental theory of design, the required hard-/software technologies to realize the dual-band and multi-beam reflectarray antenna. Target applications focus on the satellite DTV reception, which may require multi-beam radiation at Ku and Ka-bands. The works are very useful in the satellite antenna industries, and may be also applied in the future communications that requires very high antenna gains.反射陣列天線雙頻天線全金屬天線結構Reflectarray AntennasDual-band operationAll-metal antenna