因應科技的進步，高速的數位電路應用愈趨廣泛，傳輸速度也日益加快，以電腦週邊為例，為了提昇整體效能，中央處理器到顯像控制的PCI-Express2、硬碟資料存取的SATA2/ SATA3介面、及高畫質影像傳輸的HDMI 1.3/ Display port、網際網路遠距傳輸的10GBE乙太網路介面，速度需求從3 GHz開始一直到10 GHz，正在制定中的規格皆有向更高速發展的趨勢。因應高速、低耗電及抗雜訊的考量下，電路的設計上都走向差動或平衡式的方向發展，對應在SATA及HDMI協會的規範定義上，差動式的 S 參數已漸成為必測的規格。對應在傳統的 S 參數網路分析上，並無完整平衡電路的校正及量測解決方案，但從2001年以來，陸續有使用單一信號源模擬及雙信號源真實地達到差動網路分析儀問世。 為了延續傳統雙埠網路分析儀的再利用性，本文是以傳統的兩埠網路分析儀作為主體，透過硬體架構的微波切換器，達成四埠差動式的量測，為了驗證此方法的精確度，我們以時域反射的原理，找出等效的電路並透過ADS模擬方式將誤差項移除，實驗中，以兩種不同的傳輸線及晶圓上的放大器做為範例，將結果與實際四埠的網路分析儀做分析比較，並對這幾種量測模式做綜合的討論。 When technologies have been moving very fast still high speed digital application becomes more and more popular in different applications. PC peripheral as good example, in order to improve the whole performance, we should link each component in efficient way. For CPU and VGA card, we have PCI-Express2 interface in front side bus. For data storage, we have SATA2/ SATA3 to interface with H.D.D. data transferring. For Display, there is high quality video technology as HDMI 1.3 and display port. For internet, we have 10 Gbps Ethernet as optical fiber communication to reach longer distance than before. The speed requests from 3 GHz to 10 GHz and later application will definitely need higher speed to fulfill bandwidth requirement. To make high speed dream world real, digital circuit designs dominate the differential topology which shows benefit of low power consumption and noise suppression. As test standard defined by SATA or HDMI society, mixed-mode S-parameter is one of the necessary items for applying the certification logo. But as compared to traditional Vector Network Analyzer, its 2-port and single ended structure cannot meet modern applications. Another choice is using virtual or true differential 4-port VNA announced after 2001. In order to reutilize the 2-port VNA, we generate the test set combined with microwave switches. With hardware switching function, we defined the individual signal path that could leverage 4-port differential measurement. We also use TDR technique in time domain platform to verify the measurement accuracy. Furthermore, this technique also provides the methodology of equivalent circuit that for further ADS simulation. In this thesis, we utilize two types of transmission line and an on-wafer LNA as the device under test, to prove the proposed algorithm, and we also use real 4-port VNA as reference for performance verification.