整合二極體及可變電容之相控陣列天線與其在衛星終端應用

Abstract

低軌道衛星為通訊系統中具有潛力的通訊技術，其中為了減少傳輸中訊號的干擾因此使用陣列天線來達成波束成形。本論文提出低軌道衛星頻段 ku-band 的陣列天線，其接收頻段為 10.7 GHz 到 12.7 GHz，而傳輸頻段為 14 GHz 到 14.5 GHz。 在陣列天線中為了要達成波束成形，需要相移器來改變不同單元間的相位。往常使用的相位陣列波束成形 IC 其成本較為昂貴，因此本論文提出以用可變電容與二極體來達成陣列天線所需的相位變化。可變電容在電壓的改變下其電容值也會隨之改變，將可變電容與正交耦合器的結合來達成 0 度到 180 度的相位變化，而二極體在電壓的改變下會形成導通或是斷路的兩種模式，將其與 U 形槽孔的貼片天線來進行結合就能夠產生 0 度與 180 度的兩個相位狀態，綜合上述兩個結構的結合就可以產生 360 度的相位變化，最終達成主動式波束成形陣列天線。

Low Earth Orbit (LEO) satellites represent a promising communication technology within communication systems. To mitigate signal interference during transmission, antenna arrays are employed for beamforming. This paper introduces an antenna array for the Ku-band frequency range of LEO satellites, with a receiving frequency range of 10.7 GHz to 12.7 GHz and a transmitting frequency range of 14 GHz to 14.5 GHz. In antenna array, achieving beamforming requires phase shifters to alter the phase between different units. The conventional use of integrated circuits (ICs) for phase array beamforming incurs high costs. Therefore, this paper proposes the use of varactors and pin diodes to achieve the necessary phase variation in antenna array. Varactors change their capacitance with voltage variation. By combining varactors with orthogonal couplers, a phase variation from 0 degrees to 180 degrees is achieved. Pin diodes, operating in either conducting or non-conducting modes based on voltage, are combined with a U-shaped slot patch antenna to generate two phase states at 0 degrees and 180 degrees. Combining the structures mentioned above results in a total of 360-degree phase variation, ultimately achieving active beamforming in antenna array.