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aDfbrtVt | 3 years ago

What aspect of migrating to GaN PA's degrades the link budget for this application?

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stephen_g|3 years ago

GaN doesn’t really change the link budget (it does have different compression characteristics than GaAs, but you just back off a little), the OP said as the size of the terminal gets smaller, so I assume they’re talking about the aperture size. You can compensate somewhat for the lost antenna gain with a higher power PA but depending on the antenna pattern, you might hit the ESD (energy spectral density) limit earlier.

aDfbrtVt|3 years ago

I see, the reduction of antenna gain with terminal miniaturization makes sense. I didn't know if the noise figure of a GaN amplifier was worse.

Why would a change in the antenna radiation pattern limit the power spectral density, is it a regulatory limit?

walrus01|3 years ago

The link budget is still often the same just the terminals are even smaller now for the smallest flyaways and manlpacks (expecting to be used in a very hot ku band spot beam) and the BUC is half the size it used to be. Cuts down in equipment transport bulk and weight.