Military designers who subscribe to another publication, Power Electronics Technology (www.powerelectronics.com), know that electronics systems face a looming problem that is far more ominous than the physical limitations of fabrication technology threatening the continuation of Moore's Law. This is the problem of thermal management. While water-cooling systems appear to be the inevitable short-term solution to this problem, such systems also impose penalties in size, weight and complexity that detract from the very performance that once distinguished semiconductor technology from electromechanical or vacuum-tube systems.

SiC technology can eliminate this conundrum in the same way that jet engines eliminated the performance barriers imposed by piston-engine technology in military aircraft. That is, through materials that allowed for high-temperature operation. Early jets were essentially twin turbines connected by a single axle, with air drawn into the forward turbine by rotation driven by the aft turbine, which was exposed to the exhaust flow of the combusting jet fuel. The development of materials capable of withstanding such high temperatures enabled this configuration, resulting in a drastic increase in power density over piston technology. It also eliminated the need for a separate cooling system, such as the radiator required by the liquid-cooled 12-cylinder Merlin engine, variations of which powered the Spitfire, and then later the P-51H to the limits of performance for propeller-driven aircraft (about 487 mph). In an article from Arkansas Power Electronics, Marcelo Schupbach and Alexander Lostetter detail how SiC systems can operate at higher temperatures and outperform silicon technology while greatly relaxing thermal management requirements to achieve the same goal: increased power density.

The other side of thermal management deals not with simplifying the transfer of heat, but eliminating the generation of unnecessary heat through careful system design. On the ground, computer equipment needed for the rapid analysis of real-time data follows the trend of conventional desktop computers toward ever-increasing power consumption, and the electricity needed to power these systems on the battlefield is a potential logistical concern. Chris DeSalvo of Agilent returns to Defense Electronics with an article that describes a system architecture for monitoring radio voice traffic that only selects and captures signals of interest, greatly reducing the back-end processing requirements for the system. This can reduce system cost and operational staffing requirements as well as energy consumption.

In cases where the presence of heat is an inevitable design constraint, the perfect complement of power reduction is energy harvesting. While there are electrical and mechanical units capable of harnessing some of the power available from a difference in temperature between a heat source and a heatsink, such as thermopiles and Sterling engines, these units are bulky and require relatively large temperature differences to produce usable power. In contrast, Ingo Stark of Thermo Life Energy introduces a micro thermoelectric generator that generates usable electricity from body heat.

While the available power from these units is relatively small, it compares to the power draw on primary batteries from micro systems, such as a wristwatch. Therefore, it has the potential to enhance military medicine by replacing wired medical sensors with wireless units, eliminating the logistical concern of batteries and the physical inconvenience of wires, especially during emergency transport. Furthermore, the available power is scalable, possibly extending the range of applications to proactive monitoring on the battlefield.

With these technologies, military system designers have the unique opportunity to equip war fighters and the military medical professionals who protect them. One such medical professional was my uncle, Dr. Harvey Rubin, who recently died after a courageous battle with cancer. Early in his career, he served as a flight surgeon aboard an aircraft carrier, the U.S.S. Shangri-La, from 1963 to 1965. He retired as a Lt. Commander, and continued to practice medicine as a civilian, specializing in heart and lung surgery. In a similar way, the armed services, as early adaptors of solutions to universal problems such as thermal management, enable military system designers to contribute to the prosperity as well as the defense of the nation they serve.