It seems that old ideas never die…they just get 3D printed. At least this is what is happening in the case of vacuum tubes, an idea that revolutionized the world only to later be replaced by solid state electronics. However, it turns out that if something was brilliant at one time, there’s usually some chance that it will get to hit a high note again.
When vacuum tubes were first introduced in 1904 by their inventor John Fleming they quickly became a basic component of the electronics in radios, televisions, and a number of other devices. They played an essential role in the development of the first computers such as the ENIAC which required 17,468 separate tubes in order to function. Since then, they have also featured in any number of television and movie depiction as the necessary props for anything related to high tech or mad scientists.
It seems that in this case, there is a strong argument for going high-tech on a lower-tech piece of equipment. Dev Palmer, program manager for INVEST in DARPA’s Microsystems Technology Office (MTO), explained why:
“The worldwide availability and proliferation of inexpensive, high-power commercial amplifiers and sources has made the electromagnetic spectrum crowded and contested in the radio frequency (RF) and microwave regions. Any time you need to operate at the outer reaches of the power-frequency parameter space, vacuum tubes are the technology of choice, but at the high millimeter-wave frequencies of interest to this program, the design and construction of VEDs is an intricate, labor-intensive process that requires exquisite modeling tools, exotic materials, and expensive, high-precision machining.”
“As you push frequencies up, you can’t use conventional manufacturing techniques anymore,” said Palmer. “If you could print the whole structure with a 3-D printer, so that everything was aligned right off the assembly line, it would make it much easier.”
DARPA has started a new research initiative and is currently awarding funding for investigation of the possibilities for creating this next generation of tiny VEDs. Innovative Vacuum Electronic Science and Technology (INVEST) will be providing grant contracts for the performance of this fundamental research that will advance the engineering know-how needed for the realization of this vision.
What do you predict will be next in bringing high-tech capabilities to old school technologies? Do vacuum tubes still have a place? Join the discussion in the 3D Printed Vacuum Tube Research forum thread at 3DPB.com.