[eagle] Re: Another idea on phased array configuration

Robert McGwier rwmcgwier at gmail.com
Fri Apr 27 12:30:09 PDT 2007

Bill Ress wrote:
> Bob,
> I don't think we'll find a device on the current marketplace that will 
> suit our efficiency needs. But, if we're willing to develop (fund) a 
> program to design and build a Class E, 1 watt, 5.7 GHz  amplifier 
> module, we might get to 70 and maybe 90% efficiency. I have seen Class E 
> X Band amplifiers with 60 to 70%. The design, including the choice of 
> active device(s) must start with the goal of being Class E since several 
> interesting parameters are in play. You just can't take a Class C 
> amplifier and "push" it into the switching mode. Perhaps a Class C 
> amplifier might be enough.

I am listening and more than willing to consider anything that gets the 
job done with a reasonable budget.

> But it's a very interesting design challenge - to be sure!! When do we 
> start??
> But, lets assume that we build amplifiers with 100% efficiency. 36 or 43 
> elements still requires 36 to 43 watts input. What has me concerned is 
> that the current satellite structure design calls for 6 solar panels 
> with, what I guess is about 25 watts per panel. That appears to be 
> consistent with the 100 watts power generation stated in the current 
> Eagle Functional Requirements.
> Are we still working with 100 watts or did I miss something??

What we are working with is "whatever we can get away with" so long as 
it meets the communications systems goals as stated in our working 
document from the San Diego meeting of last summer.  That is the system 
we want to design and the concept we wish to support.  If this involves 
us working on our own amplifier design, and not using monolithic designs 
from Hittite, etc.,  so be it.  The efficiency translates directly to 
multiple scenario big wins for us.  Class E for this is completely 

> Regards...Bill - N6GHz
> Robert McGwier wrote:
>> The Hittites were interesting,  they had potential, but they are not 
>> really efficient enough.  We will find better parts.
>> Bob


AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
"If you're going to be crazy, you have to get paid for it or
else you're going to be locked up." Hunter S. Thompson

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