Warfare has long been a motivational force behind the development of new technology. As the Allied and Axis forces battled during World War II, each side sought to improve the reliability and accuracy of their new technological weapon (radar) for any advantage in detecting the presence of an adversary. Bell Labs—one of the organizations tasked with improving the rectifier crystals used in those radar systems for RF-to-DC conversion of reflected signals—would eventually form the germanium used for those rectifiers into the first semiconductors, as well as the birth of the transistor.
These roots of radar simply reflect a trend that has been going on throughout the history of warfare: an adaptation of lessons learned on the battlefield to practical use in peacetime. Although not often associated with the commercialization of military technologies, the US Department of Defense’s (DoD’s) Defense Advanced Research Projects Agency (DARPA) plays a key role not only in encouraging the development of novel and practical technologies for the military, but also in seeing that they eventually find their way to the civilian taxpayers who initially funded their creation.
DARPA is an impressive repository of different technologies; a quick sampling of their latest activities can be found here. This is a federal agency with a broad interest in different 
technologies, including chemical, electrical, and mechanical types. The organization’s work in robotics, for example, includes liquid-based robots capable of changing colors like a chameleon to gain an advantage in stealth operations. It is safe to say that DARPA is leading the way for advances in terahertz (THz) radio technology—pushing the development of circuits and devices operating well beyond the millimeter-wave (30 to 300 GHz) frequency range. As mentioned in the news story, the THz technology supports an even larger effort as part of DARPA’s Video Synthetic Aperture Radar (ViSAR) program, which intends to produce a targeting sensor that can work through smoke and clouds.
Yet, although its accomplishments are many, DARPA is not the behemoth organization that many perceive it to be, even though it is tied to the Pentagon. It operates effectively and efficiently (albeit helped along with taxpayers’ dollars), but largely by enlisting the help of industry to pursue new technology development. In reviewing the contents of the agency’s website (www.darpa.mil), it is clear that DARPA has enlisted many talented and knowledgeable individuals in key technology areas.
DARPA is not wed to any one technology or group of technologies but, rather, is open to advances wherever they may come. The research organization looks for technologies with high potential, technologies capable of bringing dramatic improvements in performance or tactical capabilities. A number of questions arise whenever a project or technology is considered at DARPA: How much will it cost? What will it mean in terms of improving existing capabilities? How can those technologies be turned into commercial products?
DARPA’s role is unlike any of the other armed-forces research laboratories, such as the Naval Research Laboratory (NRL) or the Army Research Laboratory (ARL). Those later laboratories are more concerned with applying existing technology in practical ways, whereas DARPA looks for “out-of-the-box” solutions that might be capable of replacing even the most successful of modern technologies—such as an alternative to the cellular telephone for low-cost wireless communications. DARPA’s role in the rapid advancement of gallium nitride (GaN) devices and amplifiers is a good example of this “disruptive technology” approach. At one time, it appeared that gallium arsenide (GaAs) would be the high-frequency, solid-state technology of choice for the military for years to come, especially given the many years of investment in GaAs. As with other DARPA technologies, GaAs was quickly transitioned to the commercial sector and became a mainstay of many modern high-frequency electronic products. But given DARPA’s current interest in GaN, and the rapid expansion of GaN amplifiers and devices throughout military radar and satellite communications (satcom) systems, GaAs may one day go the way of those early germanium transistors.
DARPA even encourages small businesses to work with them—and to commercialize their efforts—through their Small Business Planning Tool (SBPT), which is available on their website (www.sbir.darpa.mil/sbpt). It is not required in any way for a company wanting to do business with DARPA, but it includes useful tools for analyzing the technology, business, and market aspects of a company’s products when it is time to commercialize those things initially sold to DARPA.