Anyone care to contribute their favorite trick for getting a fifty ohm load to behave on a circuit board, say, from DC t0 40 GHz? Looking at ways to improve just a fifty ohm resistor grounded through a via hole with catch pad. Could be stripline or microstrip, I am just curious how you compensate for parasitics. I would also consider open circuits that don't perform at DC but have extended bandwidth. Extra points if power handling is good. I will likely post a page on this topic soon. Thanks!
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
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