本論文主要提出以LC串並聯共振電路應用於微波頻段的雙工器與三工器，並以低溫共燒陶瓷（Low Temperature Co-fired Ceramic, LTCC）技術來實現微小化的電路以提供第五代行動通訊系統（5th Generation Mobile Communication Systems）的商業使用。
　利用低溫共燒陶瓷的多層特性，使用平板式電容、垂直指叉式電容與垂直螺旋式電感架構以大幅縮小多工器尺寸，且為了增加通帶選擇性，適度增加電容使在濾波器通帶附近增加零點，除了增加通帶選擇性外亦同時使得多工器保有良好的隔離度。
　第一個設計為通帶分別為4G LTE頻段（698 – 2690MHz）及5G Sub-6GHz頻段（3300 – 5850MHz）的雙工器，量測結果可得通帶698 – 2690MHz的穿透損耗最大為0.62 dB，在3300MHz的衰減可達20dB；通帶3300 – 5850MHz的穿透損耗最大為0.76 dB，在2690MHz與10300MHz的衰減可達30dB；兩個通帶間的隔離度皆大於25dB。尺寸為可滿足商用的2.5×2.0×0.65〖mm〗^3。
　第二個設計為通帶分別為4G LTE低頻頻段（500 – 960MHz）、4G LTE高頻頻段（1427 – 2690MHz）及5G Sub-6GHz頻段（3300 – 5850MHz）的三工器。量測結果可得通帶500 – 960MHz的穿透損耗最大為0.65 dB，在1427MHz的衰減可達20dB；通帶1427 – 2690MHz的穿透損耗最大為0.88 dB，在960MHz與3800MHz的衰減量達到30dB；通帶3300 – 5850MHz的穿透損耗最大為1.06 dB，在2690MHz與10300MHz衰減達到20dB；任意兩通帶間的隔離度大於22 dB。尺寸為可滿足商用的2.5×2.0×0.65〖mm〗^3。

The thesis presents practical designs for compact microwave diplexers and triplexers by using LC resonators. The circuits will be implemented with Low Temperature Co-fired Ceramic (LTCC) substrates to reach the requirement of compact size for the 5th Generation Mobile Communication Systems.
In multi-layered structures in LTCC substrates, vertical interdigitated capacitor, metal in metal (MIM) capacitor, and vertical helical inductor can be easily implemented. Therefore, compact multiplexers can be achieved, and transmission zeros near passbands can be introduced to enhance selectivity and isolation of the multiplexers.
The proposed diplexer is operated in two passbands: 698 – 2690MHz for 4G LTE and 3300 – 5850MHz for 5G Sub-6GHz. The measured characteristics in the lower band and upper band are given as follows. Low insertion losses are 0.62 dB and 0.76 dB. The rejection of out band are over 20 dB and 30 dB. The isolation are over 25 dB between two passbands. The return loss is over 18 dB in both passbands. The diplexer design occupies a volume of 2.5×2.0×0.65〖mm〗^3.
The proposed triplexer is operated in three passbands: 500 – 960MHz for 4G LTE low band, 1427 – 2690MHz for 4G LTE low band, and 3300 – 5850MHz for 5G Sub-6GHz. The measured characteristics in three passbands are described as follows. Low insertion loss is 0.65 dB, 0.88 dB and 1.06 dB in three passbands, respectively. The rejection of out band are over 20 dB, 30 dB and 20 dB. Isolation are over 22 dB between each two passband. Return losses are over 14 dB in all three passbands. The triplexer design occupies a volume of 2.5×2.0×0.65〖mm〗^3.

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