Calibration And Error Correction For Multiport Vector Network Analyzer

The vector network analyzer (VNA) has been widely used in microwave/RF research and devel-opment. Calibration and error correction is one of the key technologies. With the frequent applicationof multiport components and differential components in microwave engineering, the demand of themultiport VNA increases explosively. The whole network parameter matrix of the device under test(DUT) can be achieved with single measurement by the multiport VNA. It makes the measurementmore precise and more rapid compared with which by the two-port VNA. However, the hardwarestructure and error model of the multiport VNA is more complicated than two-port VNA which makesthe calibration and error correction more difficult. In this thesis, calibration methods are proposed forn-port VNA (n≥2). Accordingly the research works are as follows:1) According to the hardware topology of VNA, the calibration technique based on12-term errormodel is studied for VNA with three measurement channels and the calibration technique based on8-term error model is studied for VNA with four measurement channels. According to the calibrationstandards used in calibration process, the calibration techniques such as SOLT(Short-Open-Load-Thru) and TRL (Thru-Reflect-Line) methods are depicted in detail.2) The SOLT calibration technique for two-port VNA with three measurement channels based onthe10-term error model using the concept of T-matrix is proposed. In the calibration procedure thesystem errors are not necessary to be known. By this method the measurement cost is decreased andthe calibration process is simplified.3) Short-Open-Thru-Unknown Line (SOT-UL) calibration procedure is presented for two-portthree-channel VNA based on8-term error model with the offset error of the switch. Using UnknownLine (UL) standard instead of Load (L) standard in the classical SOLT calibration procedure, themeasurement cost is decreased and the calibration process is simplified.4) A general2-port block diagram with12-term error matrices is presented for the calibration ofa4-port VNA. The classical12-term error model is extended to describe the4-port network analyzer,all the coefficients in signal paths are replaced by the complex square matrices and the nodes corres-pondingly become complex vectors. The scattering matrix can be solved from the forward and reversegeneral12-term error model.