The Test Method Of Two-Port Network Input Impedance Under Coherent Excitation

The wideband electrical small antenna is an unsolved problem in the antenna field. CFA and EH are the special kind of electrical small antennas, which are composed of the coherent excitation coupling radiators. The program which uses two coherent excitation coupling radiators to realize the wideband electrical small antenna may be an effective way. It needs a equipment which measures the input impedance of the coherent excitation two-port network in the research of the kind antenna, but the test equipment doesn't exist yet.The common measurement of the two-port network'input impedance is to measure the S parameter of the two-port network, then Z is calculated by the relation of S and Z, finally the port impedance is gained by the Z. The measurement is an indirect method and can't gain the required data of the antenna intuitively, so that we try to design the direct test system of the two-port network'input impedance.The designed test method is a groping test project. In order to ensure its feasibility and validity of the designed test system, we design the input impedance test system of the single-port network and analyze the makeup parts of the system, then design input impedance test system of the two-port network and analysis the makeup parts of the system—two-channels controllable phase signal generator.In order to make the system accurate and perfect, the dissertation analyzes the source of error. We present the model of calibrating the error which is on the basis of principle of calibration of the network,analyze and construct the calibrating system. We also bring forward the method and the process of calibration according to the real condition.At the end of this dissertation, mass of experiment results is given.The single port network'test system has high veracity, while the two-port network'test system has definite error. Then, we analyze the cause of error and point out the improving aspects of two-port network test system.