A calibration module, for use in calibrating a VNA, includes ports connectable to the VNA, calibration standards, and single pole multi throw (SPMT) switches. Each SPMT includes a single pole terminal, multiple throw terminals and a shunt terminal corresponding to each multiple throw terminal. A switching path is between each throw terminal and the single pole terminal, and between each shunt terminal and the single pole terminal. Each switching path includes at least one solid state switching element. The calibration standards are selectively connectable to the ports of the calibration module by selectively controlling the switching elements. Each port of the calibration module is directly connected to a throw terminal of one of the SPMT switches. Also, unique algorithm are provided for calibrating a VNA when using a calibration impedance that is a hybrid of a reflect standard and a transmission standard, which can be achieved using the calibration module.