gammain

Calculate input reflection coefficient of two-port network

Syntax

coefficient = gammain(s_params,z0,zl)

coefficient = gammain(hs,zl)

Description

coefficient = gammain(s_params,z0,zl) calculates the input reflection coefficient of a two-port network. z0 is the reference impedance Z₀; its default value is 50 ohms. zl is the load impedance Z_l; its default value is also 50 ohms. coefficient is an M-element complex vector.

coefficient = gammain(hs,zl) calculates the input reflection coefficient of the two-port network represented by the S-parameter object hs.

Examples

Input Reflection Coefficient Calculation

Calculate the input reflection coefficients at each index of an S-parameter array.

  ckt = read(rfckt.amplifier,'default.s2p');
  s_params = ckt.NetworkData.Data;
  z0 = ckt.NetworkData.Z0;
  zl = 100;
  coefficient = gammain(s_params,z0,zl)

coefficient = 191×1 complex

  -0.7247 - 0.4813i
  -0.7323 - 0.4707i
  -0.7397 - 0.4601i
  -0.7470 - 0.4495i
  -0.7542 - 0.4389i
  -0.7612 - 0.4284i
  -0.7682 - 0.4179i
  -0.7750 - 0.4075i
  -0.7817 - 0.3972i
  -0.7883 - 0.3870i
      ⋮

Input Reflection Coefficient Calculation of S-Parameters Object

Define a S-parameters object from a file.

  s_params = sparameters('default.s2p');

Specify the load impedance.

  zl = 100;

Calculate the input reflection coefficients at each index of a sparameters object.

  coefficient = gammain(s_params,zl)

coefficient = 191×1 complex

  -0.7247 - 0.4813i
  -0.7323 - 0.4707i
  -0.7397 - 0.4601i
  -0.7470 - 0.4495i
  -0.7542 - 0.4389i
  -0.7612 - 0.4284i
  -0.7682 - 0.4179i
  -0.7750 - 0.4075i
  -0.7817 - 0.3972i
  -0.7883 - 0.3870i
      ⋮

Input Arguments

s_params — Two-port S-parameters

complex 2-by-2-by-M array

Two-port S-parameters, specified as a complex 2-by-2-by-M array. M is the number of two-port S-parameters.

Data Types: double

z0 — Reference impedance

50 (default) | positive scalar

Reference impedance, specified as a positive scalar.

Data Types: double

zl — Load impedance

50 (default) | positive scalar

Load impedance, specified as a positive scalar.

Data Types: double

hs — Two-port network

S-parameter object

Two-port network, specified as an S-parameter object.

Data Types: function_handle

Output Arguments

coefficient — Input reflection coefficient

M element complex vector

Input reflection coefficient, returned as a M element complex vector.

Algorithms

gammain uses the equation:

$${\Gamma }_{in}=S_{11}+\frac{(S_{12}{S}_{21}){\Gamma }_L}{1-S_{22}{\Gamma }_L}$$

where

$${\Gamma }_L=\frac{Z_l-Z_0}{Z_l+Z_0}$$

Version History

Introduced before R2006a