The follwoing was excerpted from:

T&MW Online-- What are S-parameters, anyway?
http://www.tucker.com/Manufacturer/TMWorld/TMFEB01_Spara.pdf

Excerpt:

The measurement examples and corresponding S-parameter
matrices shown in Figure 6 are based on a vector network
analyzer and S-parameter test set having 50-W characteristic
impedance.

If you connect a 25-W resistor to port 1 and leave port 2
unused (Figure 6a), the S-parameter matrix reduces to a
single parameter (the resistor is a one-port network requiring
a 1x1 matrix), which represents the reflection coefficient.

The following equation (Ref. 3) describes the reflection
coefficient due to a load impedance ZL with respect to
characteristic (system or line) impedance Z0:

rho =3D (ZL - Z0)/(ZL + Z0)    (Eq. 21)

For the values shown in Figure 6a,

rho =3D s11 =3D (25 W-50 W)/(25 W+50 W) =3D -0.333,

or 0.333 with a 180=B0 phase angle.


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Further ref:

http://www.sss-mag.com/pdf/AN154.pdf
http://www.sss-mag.com/pdf/hpan95-1.pdf

* * * * * * * * * * * * * * * * * * * * * * * * * *

Jim


----- Original Message -----
From: "Jim" <jvpoll@dallas.net>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Tuesday, July 09, 2002 9:29 PM
Subject: Re: [EE]: Directional couplers & T/R test sets


> For future reference (note to self!):
>
> Agilent AN 154
> S-Parameter Design
> Application Note
>
> http://www.sss-mag.com/pdf/AN154.pdf
>
> Jim
>
> --
> http://www.piclist.com#nomail Going offline? Don't AutoReply us!
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>
>

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