I’ve put SMT resistors film-side down, and used two 100 in parallel for edge currents, but the former does not lend itself to automated assembly. I did measure this at 67 GHz with 0201 resistors and it was about 10 dB return loss; it was done in a pinch. Though I’ve also just seen dangling traces for rat-race termination at mmWave.

I’d like to try dropping one (or multiple in parallel) vertically into a non-plated hole, which should give a better field termination. In the end, the field is what matters, like a wedge absorber in a waveguide, TEM should be similar.

Many years ago I did simulate an exponentially tapered thin-film on AlN termination that looked good; high power and broad band, but never fabbed it.

There’s just no time to experiment with these things

Very interesting idea, dropping a small resistor into a non-plated hole.

I had good success with film-side down mounted SMT resistors, using standard non-RF rated 0402 components up to 20GHz. Above that, I used the fancy RF stuff from Vishay, mounted in the usual way.

I also have to agree on that there's unfortunately no time to experiment with these things.

Wow, great minds think alike. I also built a tapered resistive open-circuit stub. You can tune it with some conductive stripes, i.e. the load is like five resistors in series. I will have to dig that up and take a photo. Of course it was on alumina, lately everything is on circuit boards.

I'd post some images of it but I can't figure out how to do that here...

It’s interesting that if you make it long enough, with the proper taper, you don’t need to ground it if you can live with a high pass response. Really just a lossy transmission line or an open-ended attenuator, or using minimum loss pads to impedance match a short circuit.

Circling back to the original intent of this thread, I was looking for a way to tune a cheap thick-film resistor, grounded with an inductive via hole. Adding some tuning stubs and changing the resistor value are all fair game, or any other tricks you might have. I don't want to worry about radiated power, but I was thinking the resistor would be mounted to exposed traces (microstrip, not stripline). DC to 40 GHz with 20 dB return loss would be nice... and performance to 60 GHz would be appreciated. I'll post what I come up with at some point.