[eagle] Re: Another idea on phased array configuration

Bill Ress bill at hsmicrowave.com
Fri Apr 27 10:16:33 PDT 2007


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.

But it's a very interesting design challenge - to be sure!! When do we 

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??

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
> Louis McFadin wrote:
>> For 43 of the Hittite devices it would take 132 w to deliver 43w of RF.  
>> This doesn't count the circuitry needed to drive the finals or other 
>> spacecraft requirements.
>> This will also present a huge thermal problem with the need to dump 
>> around 100w of heat on the top of the spacecraft.
>> At least 250w of solar capacity would be needed to support this based on 
>> current requirements.

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