Author Topic: DARPA INVEST: new vacuum tubes  (Read 2098 times)

Offline savuporo

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DARPA INVEST: new vacuum tubes
« on: 09/27/2015 10:16 PM »
DARPA recently announced a program to invest in new vacuum electronics.

http://www.darpa.mil/news-events/2015-08-11

Why this matters : most commercial space revenue is almost directly generated by devices called TWTs, core vacuum tube component of comsat transponders, which are basically commercial satellite industry money printers.  Almost all of the current TWTs are manufactured by Thales and L3 according to most sources, although apparently India and China and NEC in Japan must have their own devices.

Making TWTs is currently labor intensive, has poor yields, is arcane and cannot be easily automated, and is frequently the bottleneck component for completing a comsat build. I would assume, they are also expensive.

DARPA's aim seems to be strengthening the supplier base, employ modern design and manufacturing methods ( additive manufacturing, micromachining etc ) and come up with better devices in new frequency ranges.

Modernizing this would have a potential to give massive boost to commercial space industry, although i'm guessing DARPA has military applications first in mind.

Quote
TWT production is limited to a handful of manufacturers throughout the world; major suppliers include
CPI, L-3 and Teledyne in the US, e2v,Thales and TMD in Europe, NEC in Japan, and several developing manufacturers in both India and China

Quote
Thales and L3 say it typically takes about a year to produce a Ka-band TWT. The cycles needed to hand-attach some of the 1,000 parts that go into a single tube, to “burn in” the tube, to verify its performance in thermal vacuum chambers — none of these things can be easily accelerated or automated, Auboin and Ozovek said

Sources for quotes : a few articles from Peter de Selding

http://spacenews.com/component-crunch-slows-delivery-ka-band-communications-sats/
http://spacenews.com/traveling-wave-tube-competitors-unite-behind-standardization-push-0/
http://spacenews.com/editorial-one-size-all/

http://www.e2v.com/shared/content/resources/File/documents/cctwts/TRAVELLING_WAVE_TUBE_WJ_10M28.pdf
The diary of a TWT engineer: vacuum tubes don't suck
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6571161
https://www.thalesgroup.com/sites/default/files/asset/document/space_x_uk_1.pdf
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Offline Lee Jay

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Re: DARPA INVEST: new vacuum tubes
« Reply #2 on: 09/29/2015 09:52 PM »
Just saw where one of the projects of the new 3D printers was vacuum tubes.

If I find it, will post it.

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Offline savuporo

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Re: DARPA INVEST: new vacuum tubes
« Reply #3 on: 07/24/2017 04:41 AM »
Looks like there there are some related developments, or that DARPA grant was just aimed at this company.

http://www.redorbit.com/news/science/1113392068/teraphysics-amplifier-enables-150-gbps-wireless-links/


http://www.teraphysics.com/overview

Quote
With its recent developments, mmLink™  is poised to dominate the emerging mmw mmw communications industry with a family of miniature helical traveling wave tube amplifiers with unprecedented bandwidth and gain flatness. The first prototype mmw helical TWT, helical TWT, a 94 GHz, 26 Watt amplifier with an efficiency of 53% funded by NASA JPLand DARPA, is in test and is achieving predicted results.  This tube is capable of operating from 73.5 to 96.5 GHz.  The TWT weighs 18.5 ounces and has the footprint of a business card. Compared to conventional TWTs, this is a weight and size reduction of approximately 90%

..
The Teraphysics devices have been designed from the start for volume manufacturability.  Typically, experimental devices are fabricated one at a time, but, even as prototypes, the Teraphysics TWTs are manufactured in batches.   Teraphysics has drawn upon the expertise of specialized contractors in diverse locations.


EDIT: ah yes
Quote
In January 2016 we were selected by DARPA for a $1.57 million, four year award from the INVEST program which will begin in April 2016. These contracts all support the development of technology that parallels our interest in commercial telecommunications.
« Last Edit: 07/24/2017 04:45 AM by savuporo »
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Offline john smith 19

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Re: DARPA INVEST: new vacuum tubes
« Reply #4 on: 08/06/2017 09:46 AM »
Looks like there there are some related developments, or that DARPA grant was just aimed at this company.

http://www.redorbit.com/news/science/1113392068/teraphysics-amplifier-enables-150-gbps-wireless-links/


http://www.teraphysics.com/overview
They seem rather coy about what output power they are getting.
For comm sat TWT's I think they need to be getting around 1Kw per unit at least.

Note the bandwidth however. 26 GHz of bandwidth, not MHz. That's quite astonishing.
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