Partially answering own question.... Faber, Chramiec and Adamski, Microwave and Milliieter Wave Diode Frequency Multipliers....

https://www.amazon.com/Microwave-Millimeter-Wave-Frequency-Multipliers-Hardcover/dp/0890066116

out of print and out of stock.

Thanks! Later this year I will try to do some measurements on PIN diode switches on a spec an... If this Covid thing dies down...

Out mixer spreadsheet has been updated to fix the high-side group delay issue, grab a copy here.

https://www.microwaves101.com/download-area#SparMixer

You are referring to this, correct?

https://www.microwaves101.com/encyclopedias/history-of-microwave-software#handy

Steve

Totally agree. Combine a good process and good people and there is nothing to worry about. This was more of a thought experiment gone awry! Thanks Desert Sage.

I did not consider TDR, thanks madengr!

Note to readers... you need to log in to see the photo!

Steve

and yes, madengr... no access to the ports....

That seems like a very good idea! My concern is for a combiner where they are assembled with eentsie chip resistors, thinking that the solder process could short them out or leave them open...

I think I can answer my own question... the amplifiers should see a good match with a reactive combiner. This is apparent when the amplifier is analyzed in even mode where both ports are excited equally.

It turns out that when you "mix" S-parameters with high-side LO, you need to take the conjugate of S21 and S12, and then group delay comes out as expected. I did not make this up, it is detailed in a paper by Dr. Dylan Williams...I'll post some updates on this shortly....

Thanks to Frauke for pointing this out. Here is the reference:

D. F. Williams, F. Ndagijimana, K. A. Remley, J. A. Dunsmore and S. Hubert, "Scattering-parameter models and representations for microwave mixers," in IEEE Transactions on Microwave Theory and Techniques, vol. 53, no. 1, pp. 314-321, Jan. 2005,

I know that plating plastic is possible, and some companies do it well. But the devil is in the details. Not just in the plating but in holding tolerances on the plastic part. I am considering adding an entry on this on our career killer page... good luck!

Steve

You might try Microsemi

https://www.microsemi.com/product-directory/rf-microwave-a-millimeter-wave/3592-rf-discretes

Their web site states:

"Microsemi also can offer a significant number of existing configurations to minimize your NRE and provides many customers with microwave components no longer available from their original suppliers. Microsemi's extensive library of products and designs gives us the ability to respond quickly with solutions to meet your needs, quickly and cost effectively."

Good luck!
Steve

Uli's list has circular waveguide dimensions:

https://www.microwaves101.com/encyclopedias/rectangular-waveguide-dimensions

I will forward this message post to him to see if he has any advice.

Steve

I think the best consideration is to stay away from minimum widths that would be hard to resolve in manufacturing. Maybe one way to think about this is that the RF currents will be crowded to the edges of the strips no matter what the width. That's all I have..

Steve

Andrea

all good points! Any discussion of very high impedance transmission line should start with the caveat that for all practical purposes you cannot do much better than a few hundred ohms (for example, wirebond high above a ground plane) before the media falls apart and is useless.

Thanks for the discussion!
I am going to answer my own question after thinking about this some more... impedance is defined as SQRT(L'/C').

if a microstrip is infinitely separated from its groundplane, the capacitance would be zero, and it would have infinite impedance! and infinitely useless.

This came about from playing with the wire-over-ground calculator, and observing what happens when the wire is a mile above ground.

https://www.microwaves101.com/calculators/874-wire-over-ground-calculator

This just in.... we have some data on a self-biased amplifier where the current drops when it is saturated. I guess this is yet another good reason NOT to use the self-biased trick on a power amp or driver amp... as the power will be limited by the shift in quiescent point.

Jim... we will put this into the monthly email blast. Hopefully get someone's attention!
Steve

That is too hard of a question for me! Can you simulate it in HFSS? Also, if there was a way to make "air microstrip" I think we could call it TEM at last. Maybe we could use magnetic levitation to hold up the conductor.

Steve

OK, I think I get it. The reason I asked is because of an "Excel mixer" I am playing with. Here is a page on it, it is still a mess

https://www.microwaves101.com/encyclopedias/excel-s-parameter-mixer

when I "mix" and amplifier's S-parameters to another frequency using high-side LO and look at group delay it is negative. But that is not a physical thing, just a figment of a slightly bogus way to simulate a receiver, right?

Thanks