| 摘要: | 本論文整合濾波器與天線的性能設計運用於衛星領域的濾波天線架構，並透過電磁模擬軟體Ansys HFSS與熱流模擬軟體Ansys Icepak的應用結合，實行電熱耦合模擬分析，此方法同時將電磁模擬與材料性質受到溫度影響的特性綜合考量，因此能夠更全面地掌握實際環境在使用上所面臨的挑戰，接著根據溫度造成電性數據上的偏移，經由演算法修正濾波天線設計結構來改善問題點。
第一部分會設計在X波段中的10 GHz濾波天線，利用基板合成波導的技術，使其擁有低損耗、高功率傳輸和緊湊性等特性，並調整濾波天線(結構A)中腔體的尺寸，用以改善頻寬範圍，其S11之-10 dB頻寬範圍是9.917至10.099 GHz，頻寬百分比為1.819%。第二部分進一步探討溫度對電性數據的影響，本論文經由進行電熱耦合的量測，發現當外部環境溫度降低至-55℃時，S參數的中心頻率會往高頻偏移0.017 GHz；當外部環境溫度升高至100℃時，S參數的中心頻率則會往低頻偏移0.0185 GHz。第三部分則經由貝葉斯優化之代理模型去改善溫度因子造成電性數據偏移的影響，本研究訂定目標頻帶範圍為9.984至10.166 GHz，並儘可能在影響頻寬範圍最小的情況下，達到改善溫度導致頻率頻移的問題，而在溫點-55℃的外部環境下，最佳化模擬結構(結構E)的S11之-10 dB頻寬範圍是9.983至10.199 GHz，其頻寬百分比為2.141%；在溫點25℃的外部環境下，結構E的S11之-10 dB頻寬範圍是9.965至10.183 GHz，其頻寬百分比為2.164%；在溫點100℃的外部環境下，結構E的S11之-10 dB頻寬範圍是9.951至10.169 GHz，其頻寬百分比為2.167%。由上述可知，在三個溫點(-55℃、25℃、100℃)的環境下皆能涵蓋目標頻帶範圍(9.984至10.166 GHz)，提升濾波天線在不同環境溫度下的穩定性。;This thesis integrates the performance design of filters and antennas into a filtenna architecture suitable for satellite applications. By combining the use of electromagnetic simulation software Ansys HFSS with thermal simulation software Ansys Icepak, an electrothermal coupling analysis is conducted. This approach simultaneously accounts for electromagnetic behavior and the temperature-dependent properties of materials, enabling a more comprehensive understanding of the challenges encountered under real-world operating conditions. Based on the frequency deviation caused by temperature variations, the filtenna structure is optimized through algorithmic correction to mitigate performance degradation.
In the first part, a 10 GHz filtenna operating in the X-band is designed using Substrate Integrated Waveguide (SIW) technology, which offers advantages such as low loss, high power handling, and compactness. By adjusting the cavity dimensions in the filtenna (Structure A), the bandwidth is improved. The measured |S11| −10 dB bandwidth spans from 9.917 GHz to 10.099 GHz, yielding a fractional bandwidth of 1.819%.
The second part investigates the effect of temperature on electrical performance. Through electrothermal coupling simulations, it is observed that when the ambient temperature drops to −55°C, the center frequency shifts upward by 0.017 GHz; conversely, when the temperature rises to 100°C, the center frequency shifts downward by 0.0185 GHz.
In the third part, a Bayesian optimization surrogate model is employed to mitigate the frequency shift induced by temperature variation. The target frequency band is set from 9.984 GHz to 10.166 GHz, and the optimization aims to maintain this band with minimal bandwidth distortion. At −55°C, the optimized structure (Structure E) exhibits a −10 dB |S11| bandwidth from 9.983 GHz to 10.199 GHz, corresponding to a 2.141% fractional bandwidth. At 25°C, the bandwidth ranges from 9.965 GHz to 10.183 GHz (2.164%), and at 100°C, from 9.951 GHz to 10.169 GHz (2.167%). These results confirm that the target band is fully covered across all three temperature points (−55°C, 25°C, and 100°C), demonstrating enhanced frequency stability of the filtenna under varying thermal conditions. |
