本論文以微型暨積體化雙頻被動電路為設計目標，提供較為簡單並能大幅縮小尺寸的電路設計方式。本論文將以雙頻橋式T線圈取代傳統橋式T線圈，而能將單頻電路轉換成雙頻電路，進而達成雙頻暨微型化的設計目標，並應用於兩種不同規格的雙頻枝幹耦合器。除此之外，也提出新式雙頻雙表現混成耦合器，使其低高頻分別具有180°與90°混成耦合器的頻率響應。上述的雙頻元件並以積體被動元件（IPD）與砷化鎵（GaAs）製程實現，驗證其電路效能，其中雙頻枝幹耦合器的操作頻率皆為2.45 GHz與5.5 GHz，在兩個操作頻率下的電氣尺寸分別約為0.018 λ0 × 0.011 λ0與0.040 λ0 × 0.024 λ0；而雙頻雙表現耦合器的操作頻率為2.45 GHz與5.5 GHz，在兩個操作頻率下的電氣尺寸分別約為0.025 λ0 × 0.025 λ0與0.056 λ0 × 0.055 λ0，電路面積皆小於既有文獻，驗證了雙頻橋式T線圈的確可以取代傳輸線，並且能夠大幅縮小被動電路的電路面積。除此之外，也可簡化雙頻或雙表現被動電路設計的複雜度。

In this study, miniature integrated dual-band microwave passive circuits are proposed. It provides a simple design method for miniaturization and dual-band operation. Conventional bridged-T coil replacing transmission line for miniaturization merely deals with single-band. Therefore, dual-band bridged-T coil is used to replace conventional bridged-T coil to design not only miniature but also dual-band microwave passive circuits. Here, miniature dual-band branch-line coupler and dual-behavior hybrid are realized by using dual-band bridged-T coil in Integrated Passive Device (IPD) and Gallium Arsenide (GaAs) processes. First, miniature dual-band branch-line couplers are presented. Operating frequencies of proposed circuits are at 2.45 GHz and 5.5 GHz. The electrical size of proposed circuit are around 0.018 λ0 × 0.011 λ0 at 2.45 GHz and 0.040 λ0 × 0.024 λ0 at 5.5 GHz. Second, miniature dual-band dual-behavior hybrid is presented. Operating frequencies of proposed circuits are at 2.45 GHz and 5.5 GHz. The electrical size of proposed circuit are around 0.025 λ0 × 0.025 λ0 at 2.45 GHz and 0.056 λ0 × 0.055 λ0 at 5.5 GHz. All of dual-band microwave passive circuits mentioned previously are undersized than the existing literatures. A novel dual-behavior hybrid with distinct responses in two operating bands is also presented. It proves that dual-band bridged-T coil can replace the transmission line and miniaturize microwave passive circuit size. In addition, it can reduce the complexity of dual-band or dual-band dual-behavior microwave passive circuits.

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