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Simulators >> RF Simulators >> What does this mean in ADS --> S[1::2,1::2]
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Message started by DoYouLinux on Jul 17^th, 2010, 9:51am

Title: What does this mean in ADS --> S[1::2,1::2]
Post by DoYouLinux on Jul 17^th, 2010, 9:51am

Hi everyone,

I am trying to study about S parameters in ADS. I have seen from a file that in the "stoy" function, there is a variable defined in Mea Eqn as follows:

Param_y = stoy(S[1::2,1::2]).

In the schematic, there is an element called "S2P" driven by two ports Port 1 and Port 2. I guess that this is to transform S paramters to Y parameters. But, what does the syntax

S[1::2, 1::2] mean ?

Could someone explain to me please ?

Thank you very much,

DYL

Title: Re: What does this mean in ADS --> S[1::2,1::2]
Post by pancho_hideboo on Jul 18^th, 2010, 3:12am

See http://www.edaboard.com/ftopic400964.html

Title: Re: What does this mean in ADS --> S[1::2,1::2]
Post by RFICDUDE on Jul 18^th, 2010, 4:02pm

Pancho's link explains what the notation means, but if you want to know a simple way to use the stoy function just use (I think)

stoy(S)

or if you prefer or need z-parameters

stoz(S)

these functions will save the y and z parameter equivalent results for each s-parameter analysis simulation (all ports).

The wildcard and sequence notation would be useful if you are only interested in doing a conversion for some select ports (I think).

I use these functions when I'm interested in calculating the either the series or shunt effective lumped element equivalent resistance, capacitance and/or inductance over frequency.

Title: Re: What does this mean in ADS --> S[1::2,1::2]
Post by pancho_hideboo on Jul 26^th, 2010, 4:57am

"[]", "()" and "{}" have completely different meanings each other in Agilent ADS Post Processing Environment.
S parameters are matrix, here you have to use "()" not "[]".

Usually sequence operator, "::" is used for Array not Matrix.
And if we use sequence operators for two-dimensional Array or Matrix, an applied indexing order such as "Row-Major" or "Colum-Major" is ambiguous.

So I confirmed validity of sequence operator, "::" for two-dimensional Matrix.
It seems an indexing is "Row-Major" as same as C-language.

Title: Re: What does this mean in ADS --> S[1::2,1::2]
Post by DoYouLinux on Jul 26^th, 2010, 6:57am

Hi RFDUDE,

Thank you very much for your explanation.

DYL

Title: Re: What does this mean in ADS --> S[1::2,1::2]
Post by DoYouLinux on Jul 26^th, 2010, 7:10am

Hi pancho_hideboo,

Thank you very much for your answer. I actually used S(1::2,1::2) in my simulation, not S[1::2,1::2]. I have some further questions regarding your simulation:

1) How did you generate the input S parameters ( S(1,1) = 11+j0, S(1,2) = 12+j0, ...) ?

2) What is the main difference between using S(3::4,3::4) and S{{S33,S34},{S43,S44}} ? I think the result should be the same.

Thank you in advance :)

DYL

Title: Re: What does this mean in ADS --> S[1::2,1::2]
Post by DoYouLinux on Jul 26^th, 2010, 7:23am

Ah, my fault, I mean comparison between S(3::4,3::4) and {{S33,S34},{S43,S44}}, the result should be the same.

DYL

Title: Re: What does this mean in ADS --> S[1::2,1::2]
Post by pancho_hideboo on Jul 26^th, 2010, 8:24pm

DoYouLinux wrote on Jul 26^th, 2010, 7:10am:

1) How did you generate the input S parameters ( S(1,1) = 11+j0, S(1,2) = 12+j0, ...) ?

See attached figure.
http://edocs.soco.agilent.com/display/ads2009/S1P+Eqn+to+S6P+Eqn+%281-+to+6-Port+S-parameters%2C+Equation-Based%29

DoYouLinux wrote on Jul 26^th, 2010, 7:10am:

2) What is the main difference between using S(3::4,3::4) and {{S33,S34},{S43,S44}} ?
I think the result should be the same.

Right.

Title: Re: What does this mean in ADS --> S[1::2,1::2]
Post by DoYouLinux on Jul 27^th, 2010, 6:29pm

Hi pancho_hideboo,

Thank you very much for your reply. This is my another new knowledge about ADS.

DYL