本論文將探討慢波結構具有較大的傳播常數之特性，並以此實現天線尺寸的
縮小化。且會基於類表面電漿的理論說明天線所激發的色散曲線在接近漸進線的
頻率下有圓極化模態，並以此選定天線的操作頻率，最後會用特徵模態分析驗證
其理論。
第一部分會設計 Sub-6 GHz 頻段中的 2.45GHz 微型圓極化槽孔天線，結合
LC 電路的理論以降低天線的共振頻率，最後成功設計出尺寸僅有 0.09??0 ×0.06??0
的微型圓極化槽孔天線。第二部分則是設計毫米波頻段中的 28GHz 微型圓極化
槽孔天線，槽孔的尺寸為 0.07??0 ×0.09??0。第三部分會將 2.45GHz 微型圓極化槽
孔天線設計成 1x4 天線陣列，並加上合適的蕈狀結構以增加天線彼此間的隔離
度，並且會利用巴特勒矩陣作為饋電網路以達到波束轉換的目的。最後部份則討
論了 28 GHz 微型圓極化槽孔天線陣列無法做到圓極化輻射的原因，並且會在未
來工作做改善。
;This paper will utilize the properties of slow-wave structures with larger
propagation constants to miniaturize the antenna. The theory of Spoof surface plasmons
will be employed to derive the dispersion curve of the antenna, exhibiting circular
polarization modes near the asymptotic frequency. The operating frequency of the
antenna will be determined based on this, and the theoretical analysis will be validated
through characteristic mode analysis.
The first part of the paper will design a 2.45 GHz miniaturized circularly polarized
slot antenna in the Sub-6 GHz frequency band. The addition of an LC circuit will be
used to theoretically lower the resonant frequency of antenna, ultimately resulting in
the successful design of a miniaturized circularly polarized slot antenna with
dimensions as small as 0.09??0 ×0.06??0.
The second part of the paper will design a 28 GHz miniaturized circularly
polarized slot antenna in the millimeter-wave frequency band with slot dimensions of
0.07??0 ×0.09??0.
In the third part, the 2.45 GHz miniaturized circularly polarized slot antenna will
be designed as a 1x4 antenna array, and a suitable mushroom structure will be added to
increase the isolation between the antennas. The Butler matrix will be used as a feeding
network to achieve beamforming.
The last part will discuss the reasons why circularly polarized radiation cannot be
achieved in the 28 GHz miniaturized circularly polarized slot antenna array and propose
potential improvements for future work.
