CST - Impedance matching to imported touchstone / S-parameter file

[dom11990]

Hi all,

I have a chip who's S-Parameter's I know and I would like to match it to an E-Band antenna. Of course, the bondwire will completely ruing the otherwise decent output impedance of the chip. I'm sure I can model the bondwire in CST, however, I'm not sure how to model the frequency varying complex impedance of the chip or the antenna so I can design an appropriate matching network. Is it possible to insert a sort S1p lumped component? What is the best way to approach this type of problem? Any insights would be greatly appreciated!

cheers
dominik

 

[vfone]

At mmWave frequencies as E-band, the equivalent of bond wire is a very complex circuit.

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At lower frequencies (up to couple of GHz) the bond wire can be modeled as a series inductor (about 1nH/mm)

 

[volker@muehlhaus]

I'm not sure how to model the frequency varying complex impedance of the chip or the antenna so I can design an appropriate matching network.

A good starting point is to model it as an inductor, and add shunt C on each side to form a low pass filter. That will improve return loss over a reasonable frequency range, compared to the bondwire only.

Time domain analysis can also be useful in some cases, to identify the location of discontinuities. I have an appnote on my website, but can't post a link because then vfone will start complaining about advertising :-(