天線是通訊系統中重要的組成部分，不同應用場景的天線設計在增益、頻寬、極化和尺寸等方面存在很大差異，但所有天線設計都追求低損耗的理想情況，阻抗不匹配是導致損耗的主要原因，其可能發生在天線與饋電之間的界面處，阻抗不匹配會導致理想情況下饋送進天線的能量被反射回饋電處，從而降低輻射效率，引起反射波和入射波之間的干擾，甚至可能損壞元件，為了解決這個問題，光子拓撲絕緣體被提出作為一種新興的解決方案，其是在光子晶體的基礎上結合拓樸性質的材料，使能量侷限在材料的結構界面裡，並沿單一方向傳播，這種傳播現象對於反射和散射具有堅固性，其稱為拓樸邊緣態，拓樸邊緣態的特性使天線與饋送之間的邊界處，即使遇到阻抗不匹配也不會導致波被反射回拓撲波導。
本篇論文為在60GHz下使用微帶線和光子拓樸絕緣體當作天線的饋送波導，首先，我們使用FDTD方法對微帶線饋送的縫隙天線進行模擬後，將基板換成液晶後，透過液晶調控天線之間的相位差，並利用微帶線將訊號饋送給陣列縫隙天線，分析其激發效率、相位和輻射特性。接下來為了增加天線之間的激發相位差，加入將微帶線加入蜿蜒線結構，分析其激發效率、相位和輻射特性。最後對拓撲波導模式進行了模擬，透過基於量子自旋霍爾效應和量子谷霍爾效應的拓樸波導，以拓樸邊緣態將訊號饋送給縫隙天線，分析其激發效率、相位和輻射特性，最後比較與微帶線的差異。

Antennas are crucial for communication systems, and different antenna applications require specific parameters such as gain, bandwidth, polarization, and size. However, the goal of all antenna designs is low loss. Impedance mismatch at the antenna-feed interface is a major contribution to losses, leading to reduced radiation efficiency, interference, and device damage. To solve the above problems, photonic topological insulators have been proposed as an emerging solution. Photonic topological insulators provide a promising solution by utilizing the topological properties of photonic crystals. They confine energy within the interface of the material, propagating in one direction, known as topological edge states. This phenomenon resists reflections and scattering, ensuring that the waves are not reflected back even if the impedances are not matched.
This investigation was conducted to simulate microstrip-lines and photonic topological insulators as feeding waveguides for a 60 GHz slot antenna. A slot antenna fed by a microstrip-line was first simulated using the FDTD method. To dynamically change the excitation efficiency, phase, and radiation characteristics the substrate is replaced with liquid crystal to control the phase between each slot antenna. In order to further enhance the phase difference, meander-lines were introduced in adjacent antennas. Finally, topological waveguides were introduced to feed signals to slot antennas using topological edge states based on the quantum spin Hall effect and the quantum valley Hall effect. The excitation efficiency, phase, and radiation characteristics with the microstrip-line and topological waveguide were compared.

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