Yes, for solid state microwaves that do not have to have any form of
communication (since you then don't have to worry about linearity), the
efficiencies can easily go above 80% with class E and class F GaN amplifiers
(GaNs are also radiation tolerant).
However that's still going to have to radiate more than 100 kW away from the
spacecraft(which might be about what the ISS has to radiate away?) at a 90%
efficiency case and 250kW for 80% efficiency case.
Regarding the rectennas, you can power divide the antenna and have each antenna
element have a lower power amplifier on it (might have to watch to phase
closely for interference patterns).
The biggest issue that I see that could happen with a really high power
microwave satellite is multipaction increasing degradation of the amplifier
components and possibly the antenna elements (producing higher reflection which
creates even more heat). At lower frequencies you'll have more multipaction
issues (say 2.4 GHz and lower) vs higher frequencies (10 GHz) which can have
more insertion loss.
-Jordan
________________________________
From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> on behalf of
Henry Spencer <hspencer@xxxxxxxxxxxxx>
Sent: Monday, March 18, 2019 8:38:54 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: space based solar
On Tue, 19 Mar 2019, Jordan Trewitt wrote:
I just want to see what the radiators will be like on either laser or
microwave transmission satellite...