本論文以降低第一操作頻頻偏之微型化三頻微波被動電路設計為研究目標，以三個橋式T線圈(Bridged-T Coil, BTC)串接實現三頻等效傳輸線的設計方法，有效改善先前設計中第一操作頻率的頻偏問題，成功實現第一操作頻頻偏在10%以內之積體化三頻分支線耦合器、帶止濾波器及威爾金森功率分配器。以此方法設計完成之4 / 7.6 / 9.3 GHz三頻分支線耦合器，電路面積僅2.257 mm × 1.994 mm，且其頻偏比例皆在3.75%內。接續以相同方式設計三頻帶止濾波器，其操作頻率為3.73 / 7.5 / 9.1 GHz，電路面積僅1.27 mm × 2.41 mm，其第一操作頻率與設計目標4 GHz的頻偏為0.27 GHz，其頻偏比例只有6.75%。最後則是以相同方法設計之微型化之三頻威爾金森功率分配器，其操作頻率為3.64 / 7.4 / 9 GHz，電路面積僅0.824 mm × 2.014 mm，其第一操作頻率相較於設計目標4 GHz亦只有0.36 GHz的頻偏，其頻偏比例只有9%。此外，相較於既有三頻微波被動電路設計，本研究所使用之設計均成功達成大幅縮減電路面積之目標。;This thesis focuses on the design of miniaturized tri-band microwave passive circuits with significantly reduced frequency shifts at the first operating frequency. By implementing a design method that uses three cascaded Bridged-T Coils (BTC) to realize a tri-band equivalent transmission line, the frequency shift issue of the first operating frequency in previous designs is effectively improved. This approach successfully actualizes integrated tri-band branch-line couplers, bandstop filters, and Wilkinson power dividers, all with a first-band frequency shift of less than 10%. First, a miniaturized tri-band branch-line coupler was realized with operating frequencies of 4 / 7.6 / 9.3 GHz and a circuit area of 2.257 mm×1.994 mm, and all frequency deviations are within 3.75%. Subsequently, a miniaturized tri-band bandstop filter was designed using the same approach, operating at 3.73 / 7.5 / 9.1 GHz with a circuit area of just 1.27 mm × 2.41 mm. The frequency shift at its first operating frequency is 0.27 GHz relative to the 4 GHz design target, a percentage of only 6.75%. Finally, a miniaturized tri-band Wilkinson power divider was also designed with the same method. It operates at 3.64 / 7.4 / 9 GHz with circuit area of only 0.824 mm × 2.014 mm. The frequency shift at its first operating frequency is also only 0.36 GHz compared to the 4 GHz design target, which is a shift percentage of just 9%. Furthermore, compared to existing tri-band microwave passive circuit designs, all designs in this study have successfully achieved a significant reduction in circuit area.
