Practical RF Handbook, 4th Edition

Appendix 2

S-Parameters

In RF circuit design, the parameters of a single device or a complete circuit can most easily be determined by measurements made using a Vector Network Analyser, which is designed to measure the s-parameters of the device or circuit. This is done with both the input port and the output port terminated in the device’s characteristic impedance - usually 50 Ω or 75 Ω in the case of television aerials and baseband signals - this reduces the possibility of the device under test oscillating, which would make meaningful measurements impossible.

Thus s-parameters are much more amenable than h-, z- or y-parameters, which require ideal broadband short- or open-circuit terminations at the ports of the device under test. An effective ...