Dual five-port analyzer using fixed probes

A dual 5-port network analyzer using fixed electric probes is presented. To measure S₁₁ and |S₂₁|, the RF signal is applied to port 1 of the DUT through one 5-port junction. The same RF signal reflected by a short circuit at the end of the line is used for measuring S₂₂. In this way, dividers, switches, and phase shifters as used in the standard dual technique are avoided. But S₂₂ can only be measured for devices with |S₂₁|>0.3. The 5-port junctions are inexpensive and very simple to design and operate. The mathematics involved uses simple linear algorithms, and iterative methods are not needed. Measurements for several loads have been performed in X-band, and the results agree with those obtained using an HP 8510B network analyzer