本論文提出一個運用在超高頻段(UHF)無線射頻標籤(RFID)系統讀取器(Reader)之相移電路設計。以傳統的環型耦合器為基本架構，加入兩個變容二極體形成雙埠之相移結構。當電壓改變，可使電路結構具有相位變化的特性。環形耦合相移電路設計之傳輸線電氣長度在埠四及埠二之間為270度，其餘均為90度，隨著埠ㄧ及埠四的電壓改變，可以產生相移之功能。此電路利用散射矩陣求得之關係式進行電路設計及驗證。電路結構使用電磁模擬軟體Microwave Office 及 IE3D 進行模擬與量測，使用FR-4雙面板材進行實作，板材厚度為1.6mm，相對介電常數為εr= 4.3，其中心頻率設為0.925GHz以及2.45GHz，由模擬與量測結果看出電路有良好的一致性。相移電路部份由一段傳輸線與兩個變容二極體(Varactors)組成，變容二極體為Skywork公司的SMV1234。電路之中心頻率分別於0.925GHz與2.45GHz，其電壓變動範圍在0-15伏特，相位控制可從0至80度與0至53度變化。此電路具有在不改變任何元件的條件下，改變電壓可控制相位角度的特性，更有效能地提昇系統的機動性。

In this thesis, a novel phase shifter design based on conventional rat-race coupler is presented. The device is applicable to an UHF radio frequency identification (RFID) reader antenna arrays. By combining two varactors to ports 1 and 4 of the rat-race coupler forms a two-port network. The varacors are SMV1234 manufactured by Skyworks Solutions Incorporation. When the voltage applied on the varactors changes, the effective capacitance changes as well and thus results in phase-shifting. In order to exactly knowing the characteristics of the phase shifter we use the commercial electromagnetic software Microwave Office and IE3D for the circuit simulation. Two phase shifters are designed at 0.925GHz and 2.45 GHz respectively, the experimental results show that the corresponding maximum phase shifts are 80 degree and 53 degree at the circuits are implemented on glass epoxy FR4 substrate with thickness of 1.6 mm. Very good agreement is obtained between simulation and measurement data.

中文摘要 ---------------------------------------- ii
英文摘要 ---------------------------------------- iii
誌謝 ------------------------------------------- iv
目錄 -------------------------------------------- v
第一章 緒論--------------------------------------- 1
1.1 前言----------------------------------- 1
1.2 章節概述------------------------------- 3
第二章 環形耦合相移電路概論------------------------- 4
2.1 環形耦合電路簡介------------------------------ 4
2.2 相移器簡介------------------------------- 12
2.3 變容二極體簡介--------------------------- 13
第三章 環形耦合電路設計與分析---------------------- 14
3.1 相移電路設計原理----------------------------- 14
3.2 相移電路設計公式----------------------------- 15
第四章 環形耦合相移電路設計與測量------------------- 25
4.1 使用Lump元件模擬與測量------------------------ 25
4.1.1 0.925GHz相移電路製作與測量------------------ 25
4.1.2 2.45GHz相移電路製作與測量------------------- 28
4.2 使用變容二極體零件模擬設計與測量---------------- 32
4.2.1 0.925GHz相移電路製作與測量------------------ 32
4.2.2 2.45GHz相移電路製作與測量------------------- 36
4.3 使用電感零件模擬設計與測量--------------------- 40
4.3.1 0.925GHz相移電路製作與測量------------------ 40
4.3.2 2.45GHz相移電路製作與測量------------------- 43
4.4 縮小尺寸使用變容二極體零件模擬設計與測量-------- 47
4.4.1 0.925GHz相移電路製作與測量------------------ 47
第五章 結論--------------------------------------- 52
參考文獻 --------------------------------------- 55

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