步入高頻的時代後，元件尺寸隨著操作頻率的提升而必須相對遞減，造成在元件設計與製造方面難度增加。相對的，電腦運算速度與記憶體容量也隨著科技的進步而獲得提升，這使需要耗費大量系統資源的電路模擬與電磁模擬軟體，可以有較好的表現，也因此可被大量使用來輔助高頻的設計與驗證。

　　本論文有兩個主題。第一是在不改變電路板的設計下，研究如何改良SMA連接器的結構，以降低連接器與微帶線間的不連續性效應。首先以實驗數據修正電磁模擬所使用的模擬參數，以提高分析的準確性；再透過連接器電路模型的建立，對連接器的結構做設計上的研究改良；最後，再利用電磁模擬作確認。在18 GHz的操作頻率範圍內，經過改良後的連接器與微帶線間的反射損耗，已由改良前的15 dB降低至改良後的40 dB以下。

　　本論文的第二個研究主題為改良多層電容器的設計，使其操作頻寬可以增加。多層電容器的電路模型顯示，其內含的等效開路傳輸線限制了元件的操作頻寬。本研究針對多層電容器的結構作改良，以縮短此等效開路傳輸線的長度，使其操作頻寬增加。研究結果發現以六層結構為例，操作頻寬可以明顯地由原來的5 GHz頻寬改良至18 GHz以上。

After stepping into the era of high frequency, the size of devices gradually reduces. This makes the device design and manufacture more difficult. On the other hand, with the help of science and technology progress, the speed of the computations and the memory of computers are both increased significantly, and their cost are greatly reduced. Therefore, circuit and electromagnetic simulators, which require a lot of resources, could now have much better performance. Naturally, they are selected to help the design and verifying of high-frequency circuits and structures.
There are two topics in this thesis. The first one is to reduce the discontinuity between a SMA launcher and a microstrip line on a PCB, by carefully design the launcher structure but without changing the PCB layout. The research starts from the modification of the parameters used in electromagnetic simulations by measurement results. This increases the accuracy of the simulations. Then a network model is built to help the design of the connector. At last, the design is verified by electromagnetic simulations again. This research shows that the return loss could be improved significantly from 15 dB to 40 dB, below 18 GHz.
The other topic of this thesis is to design a multilayer capacitor such that its operational bandwidth could be broader. The network model of a multilayer capacitor shows that its operational bandwidth is seriously limited by the embedded opened transmission line in its structure. By modifying the structure of a multilayer capacitor to shorten the length of this open stub, the operational bandwidth could easily be improved. This research shows that, for a six-layer capacitor, the operational bandwidth could be increased noticeably from 5 GHz to at least 18 GHz.

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