Vector Network Analyzers

A multimeter measures DC resistance - but a Vector Network Analyzer (or VNA) measures the impedance of an RF or microwave circuit at its operating frequency. It measures both the resistance and the phase making up a vector response of the circuit. A VNA can also measure the gain or loss between two ports of a circuit, in magnitude and phase. So RF VNAs measure the vector response of networks so that the signal performance characteristics of RF products and other devices can be optimized. An RF system works best when its components are impedance-matched to each other, with the output impedance matching the input impedance of the next component. A VNA is helpful for determining reflection parameters and for impedance matching of components like antennas. Antennas can have a wide range of impedances, and they need to be matched to the devices that they are connected to. Measurement setups contain connectors and cabling that can introduce subtle errors in measurements. So, even though pre-calibration takes a few minutes before taking readings, it's essential to calibrate these errors out of your readings, so make sure you order a cal-kit with your VNA!