本論文主要是探討符合無線區域網路IEEE802.11b、IEEE802.11a或HiperLAN2標準規格之頻率雙工器設計。在論文中頻率雙工器的主要設計概念，在於首先設計針對符合個別頻道的濾波器，之後利用T型接面結構(T-junction)來加以整合。文中所提到的電路都是利用IE3D電磁模擬軟體來加以模擬，並以Fr4板和ARLON 25N板當作基板來實現電路。從模擬與實作結果來看，具有很好的一致性。此外，本論文並針對不同品質的材料對電路的影響加以討論。 In the thesis, the designs of the diplexers conforming the standards of IEEE802.11b、IEEE802.11a or HiperLAN2 have been discussed. To design a diplexer, the filters corresponding each frequency channel are first developed and then combined using T-junction. Many different types of filters are designed in the thesis. The behaviors of the presented circuits are all studied not only numerically using IE3D electromagnetic simulator, but also experimentally by circuit measurements. Good agreement has been obtained between simulations and experimental results. The effects of the substrate material on the quality of the circuits are also discussed.