Software defined radio for vector network analysis: Configuration, characterization and calibration

A portable vector network analyzer operating from 30 MHz to 850 MHz, using a commercial low-cost software-defined radio is described. The system can be used for transmission (S21) or, using a directional bridge, reflection measurements (S11). A complete software package is developed in order to define and operate the system as an automatic analyzer including the correction of systematic errors. The analyzer has heterodyne receivers with an specific intermediate frequency, digitizer sampling rate and block size chosen to correctly process the signals. Measurements to characterize the transmitters and receivers on the board are shown. System errors are determined by comparison with laboratory equipment measurements and manufacturer data.