s2smm

Convert single-ended S-parameters to mixed-mode S-parameters

Syntax

[s_dd,s_dc,s_cd,s_cc] = s2smm(s_params_even,rfflag)

s_mm = s2smm(s_params_odd)

Description

[s_dd,s_dc,s_cd,s_cc] = s2smm(s_params_even,rfflag) converts single-ended S-parameters to mixed-mode form.

s_mm = s2smm(s_params_odd) converts single-ended odd S-parameters matrix to mixed-mode matrix. To create a mixed-mode matrix from s_params_odd, the single-ended input ports are paired sequentially (port1 with port 2, port 3 with port 4, etc.), and the last port is left single ended.

Examples

4-Port S-Parameters to 2-Port Mixed-Mode S-Parameters

Convert 4-port S-parameters to 2-port, mixed-mode S-Parameters.

S = sparameters('default.s4p'); 
s4p = S.Parameters; 
[s_dd,s_dc,s_cd,s_cc] = s2smm(s4p);

Display the 2-port mixed-mode S-Parameters at the first frequency.

s_dd1 = s_dd(:,:,1)

s_dd1 = 2×2 complex

  -0.0124 - 0.0433i  -0.5434 - 0.6872i
  -0.5428 - 0.6900i  -0.0192 - 0.0504i

s_dc1 = s_dc(:,:,1)

s_dc1 = 2×2 complex

   0.0024 - 0.0035i  -0.0005 + 0.0019i
   0.0007 - 0.0012i   0.0023 - 0.0027i

s_cc1 = s_cc(:,:,1)

s_cc1 = 2×2 complex

   0.1799 - 0.1839i  -0.5300 - 0.6771i
  -0.5314 - 0.6800i   0.1756 - 0.1910i

s_cd = s_cd(:,:,1)

s_cd = 2×2 complex

   0.0015 - 0.0029i  -0.0005 + 0.0014i
   0.0003 - 0.0009i   0.0019 - 0.0027i

Input Arguments

s_params_even — S-parameters

2 N-by-2 N-by-K array

S-parameters, specified as a complex 2 N-by-2 N-by-K array, where K representing number of frequency points of 2 N-port S-Parameters. These parameters describe a device with an even number of ports.

rfflag — Port order

1 (default) | 2 | 3 | scalar

Port order, a scalar, specified as 1, 2, or 3. Port order determines how the function orders the ports:

• rfflag = 1 — s2smm Odd-numbered ports are followed by even-numbered ports: 1,3,5,…..,2N-4,2N-2,2N.

  

  • Ports 1 and 3 become mixed-mode pair 1.

  • Ports 5 and 7 become mixed-mode pair 2.

  • Ports 2 and 4 become mixed-mode pair 3.

  • Ports 6 and 8 become mixed-mode pair 4.

• rfflag = 2 — Ports are paired in ascending or descending order: (1,2),…..,(2N-1,2N)

  

  • Ports 1 and 2 become mixed-mode pair 1.

  • Ports 3 and 4 become mixed-mode pair 2.

  • Ports 5 and 6 become mixed-mode pair 3.

  • Ports 7 and 8 become mixed-mode pair 4.

• rfflag = 3 — Half of the ports are in ascending order and half of the ports are in descending order: 1,2,…..,N,2N,2N-1,….,N+1.

  

  • Ports 1 and 2 become mixed-mode pair 1.

  • Ports 3 and 4 become mixed-mode pair 2.

  • Ports 8 and 7 become mixed-mode pair 3.

  • Ports 6 and 5 become mixed-mode pair 4.

s_params_odd — K (2 N+1) port single-ended S-Parameters matrix

complex (2 N+1)-by-(2 N+1)-by-K array of

K (2 N+1) port single-ended S-Parameters matrix, specified as a complex (2 N+1)-by-(2 N+1)-by-K array. These parameters describe a device with an odd number of ports.

The port-ordering argument option is not available for (2N + 1)-by-(2N + 1)-by-K input arrays. In this case, the ports are always paired in ascending order, and the last port remains single-ended. For example, in a 7-port network:

• Ports 1 and 2 become mixed-mode pair 1.

• Ports 3 and 4 become mixed-mode pair 2.

• Ports 5 and 6 become mixed-mode pair 3.

• Ports 7 remains single ended.

Output Arguments

s_dd — Mixed-mode S-parameters

complex N-by-N-by-K array

Mixed-mode S-parameters, returned as complex N-by-N-by-K array, containing K matrices of differential-mode, 2N-port S-parameters (S_dd).

s_dc — Mixed-mode S-parameters

complex N-by-N-by-K array

Mixed-mode S-parameters, returned as complex N-by-N-by-K array, containing K matrices of differential-mode, 2N-port S-parameters (S_dc).

s_cd — Mixed-mode S-parameters

complex N-by-N-by-K array

Mixed-mode S-parameters, returned as complex N-by-N-by-K array, containing K matrices of differential-mode, 2N-port S-parameters (S_cd).

s_cc — Mixed-mode S-parameters

complex N-by-N-by-K array

Mixed-mode S-parameters, returned as complex N-by-N-by-K array, containing K matrices of differential-mode, 2N-port S-parameters (S_cc).

s_mm — Mixed-mode S-parameters

complex N-by-N-by-K array

Mixed-mode S-parameters, returned as complex N-by-N-by-K array, containing K matrices of differential-mode, 2N-port S-parameters (S_mm).

$$\left[\begin{array}{lllllll}{S}_{dd,11}\hfill & \cdots \hfill & S_{dd,1N}\hfill & S_{dc,11}\hfill & \cdots \hfill & S_{dc,1N}\hfill & S_{ds,1}\hfill \\ ⋮\hfill & \ddots \hfill & ⋮\hfill & ⋮\hfill & \ddots \hfill & ⋮\hfill & ⋮\hfill \\ S_{dd,N1}\hfill & \cdots \hfill & S_{dd,NN}\hfill & S_{dc,N1}\hfill & \cdots \hfill & S_{dc,NN}\hfill & S_{ds,N}\hfill \\ S_{cd,11}\hfill & \cdots \hfill & S_{cd,1N}\hfill & S_{cc,11}\hfill & \cdots \hfill & S_{cc,1N}\hfill & S_{cs,1}\hfill \\ ⋮\hfill & \ddots \hfill & ⋮\hfill & ⋮\hfill & \ddots \hfill & ⋮\hfill & ⋮\hfill \\ S_{cd,N1}\hfill & \cdots \hfill & S_{cd,NN}\hfill & S_{cc,N1}\hfill & \cdots \hfill & S_{cc,NN}\hfill & S_{cs,N}\hfill \\ S_{sd,1}\hfill & \cdots \hfill & S_{sd,N}\hfill & S_{sc,1}\hfill & \cdots \hfill & S_{sc,N}\hfill & S_{ss}\hfill \end{array}\right]$$

References

[1] Granberg, T.,Handbook of Digital Techniques for High-Speed Design. Upper Saddle River, NJ: Prentice Hall, 2004.

Version History

Introduced in R2009a