三位元平衡式數位移相器

Abstract

本論文提出於平衡式系統下的數位移相器，結合了平衡式數位移相器與寬頻180°數位移相器，運用平衡式訊號的特性，透過改變訊號的共模和差模狀態，作為不同移相角度的切換方法。 本研究設計之負載線移相器，利用八分之一波長的傳輸線殘段之開路或斷路可等效為電容或電感的特性，以平衡式系統的共模和差模作為切換；為了改變訊號的共模和差模狀態，進一步以等比傳輸線濾波器(commensurate line filter)和手繞電感兩種型式設計切換式180°數位移相器。整體電路以微帶線實現，使用的基板為Rogers RO4003，厚度為20毫英寸(20 mil)，介電係數為3.58。

In this study, the 3-bits balanced digital phase shifter is designed. The proposed phase shifter, combine from the balanced digital phase shifters and the broadband 180° digital phase shifter, changes phases while even- or odd-mode signal is excited. First, in the balanced system, the loaded line phase shifters switch loaded when excited by even- or odd-mode signal and thus change the open- or short- 1/8 wave length transmission line stubs into capacitors or inductors. In order to change the mode of signals, two type of 180°switch type digital phase shifter is designed using commensurate line filter and hand-wound inductors respectively. The circuits in this study are fabricated with microstrip line on a RO4003 substrate having a 20 mil thickness and a dielectric constant of 3.58.