Contents
What is scattering parameters and explain its characteristics and properties?
Scattering parameters or S-parameters (the elements of a scattering matrix or S-matrix) describe the electrical behavior of linear electrical networks when undergoing various steady state stimuli by electrical signals.
What does S11 mean?
S11
| Acronym | Definition |
|---|---|
| S11 | September 11 (protest organization) |
What is S22?
S22: Do not breathe dust, a safety phrase in chemistry.
What does each S-parameter mean?
S-parameters describe the response of an N-port network to signal(s) incident to any or all of the ports. The first number in the subscript refers to the responding port, while the second number refers to the incident port. Thus S21 means the response at port 2 due to a signal at port 1.
Why do we use S parameters?
S (scattering) parameters are used to characterize electrical networks using matched impedances. Here, scattering refers to the way traveling currents or voltages are affected when they meet a discontinuity in a transmission line.
Why do we use scattering parameters?
Scattering parameters describes the input-output relationships between ports in an electrical system. Specifically at high frequency it becomes essential to describe a given network in terms of waves rather than voltage or current. Thus in S-parameters we use power waves.
What are the properties of scattering matrix?
Properties of [S] Matrix
- [S] is always a square matrix of order nxn. [S]n×n.
- [S] is a symmetric matrix. i.e., Sij=Sji.
- [S] is a unitary matrix. i.e., [S][S]∗=I.
- The sum of the products of each term of any row or column multiplied by the complex conjugate of the corresponding terms of any other row or column is zero. i.e.,
What is a good S11 value?
A good compromise is -13 dB. This is the origin of the rule of thumb, that the maximum acceptable value of S11 for an interconnect structure is about -13 dB: If S11 is smaller than -13 dB, we will not see the impact from these reflections on the transmitted signal. For example, a connector has -20 dB of S11.