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S-Parameters

S-Parameters Scattering parameters or S-parameters (the elements of a scattering matrix or S-matrix) describe the electrical behaviours of linear electrical networks when undergoing various steady state stimuli by electrical signals. Although applicable at any frequency, S-parameters are mostly used for networks operating at radio frequency and microwave frequencies where signal power and energy considerations are more easily quantified than currents and voltages.S-parameters change with the frequency are readily represented in matrix form and obey the rules of matrix algebra.

Applications
The S-parameters analysis belongs to the high frequency electromagnetic, or the full wave, regime, i.e. Maxwell's displacement current that couples the electric and magnetic fields is significant and thus taken into consideration.The vector wave equation, i.e. combination of the full Maxwell's equations, is solved using vector finite element to obtain the S-parameters and the electric/magnetic fields and related design parameters.It has many practical applications, including:

  • Connectors
  • Filters
  • Couplers
  • Attenuators
  • Terminators
  • Baluns
  • Integrated Circuit
  • Waveguides
  • Power dividers
  • Multiplexers
  • Power combiners
  • Transitions

Results
The S-parameters module outputs the following results for each study at each frequency:
  • Generalized S-parameters matrix
  • Re-normalized S-parameters matrix
  • Unique impedance matrix
  • Unique admittance matrix
  • TDR
  • VSWR
  • Propagation parameters at each port
  • Impedances at each port
  • Electric field distribution
  • Magnetic field distribution
  • Specific absorption rate distribution

Examples of design issues
The S-parameters module can help study a large number of RF & microwave devices and address numerous dispersion and matching effects. Below is just a partial list:
  • Obtain the vector frequency response of arbitrary 3D circuit/structure.
  • Examine the TDR of a structure.
  • Design around a resonance.
  • Distinguish between common and differential modes.
  • Achieve a good matching over a frequency range.
  • Study the frequency response of a structure.
  • Account for both dielectric and conductor losses.
  • Study the fidelity of a high frequency structure.
  • Achieve or avoid a mode conversion.
  • Study the signal integrity of a structure.
  • Examine both propagating and evanescent modes.
  • Examine both fundamental and higher order modes.
  • Optimize pole-zero placement of a filter.
  • Study the effect of material and dimension on the circuit and field parameters.

Videos

S-Parameter Analysis of a Connector 1/2

S-Parameter Analysis of a Connector 1/2

S-Parameter Analysis of an RF Filter  1/2

S-Parameter Analysis of an RF Filter 1/2

S-Parameter Analysis of an RF Filter 2/2

S-Parameter Analysis of an RF Filter 2/2