Defense Advanced Research Projects AgencyTagged Content List

Electromagnetic Spectrum and Bandwidth

Novel concepts and technologies for maximizing use of the electromagnetic spectrum

Showing 101 results for Spectrum RSS
As wireless devices proliferate and the radio spectrum becomes ever more congested, all users have a common interest in radio technologies that can accommodate the largest number of users but still enable priority traffic to get through. The DARPA Spectrum Challenge—a competitive demonstration of robust wireless technologies—recently announced the selection of 15 of 18 semifinalists for $150,000 in prize money. DARPA plans to fill three remaining wildcard slots in August 2013 before the September 2013 semifinals at DARPA’s offices in Arlington, Va.
Radios are used for a wide range of tasks, from the most mundane to the most critical of communications, from garage door openers to first responders to military operations. Wireless devices often inadvertently interfere with and disrupt radio communications, and in battlefield environments adversaries may intentionally jam friendly communications. To stimulate the development of radio techniques that can overcome these impediments, DARPA launched its Spectrum Challenge—a competitive demonstration of robust radio technologies that seek to communicate reliably in congested and contested electromagnetic environments without direct coordination or spectrum preplanning.
The submillimeter wave, or terahertz, part of the electromagnetic spectrum falls between the frequencies of 0.3 and 3 terahertz, between microwaves and infrared light. Historically, device physics has prevented traditional solid state electronics (microchips) from operating at the terahertz scale. Unlocking this band’s potential may benefit military applications such as high data rate communications, improved radar and unique methods of spectroscopy—imaging techniques that provide better tools for scientific research. However, access to these applications is limited due to physics.
Multinational forces, U.S. government agencies and U.S. troops operating together in forward-deployed locations generally have problems communicating—and not just due to language differences. Technical incompatibility between communications systems can hinder information sharing and timely command and control decisions. DARPA’s Mobile Ad hoc Interoperability Network Gateway (MAINGATE) program is helping overcome this technology barrier. The program is nearing completion and plans to transfer the latest version of the system to Army warfighters still engaged in Afghanistan, but who are now focused more on Force Protection as U.S. forces draw down. The MAINGATE system is providing insights into tactical networking of the future, where systems will need more adaptability and capability.
High-energy lasers (HEL) have the potential to benefit a variety of military missions, particularly as weapons or as high-bandwidth communications devices. However, the massive size, weight and power requirements (SWaP) of legacy laser systems limit their use on many military platforms. Even if SWaP limitations can be overcome, turbulence manifested as density fluctuations in the atmosphere increase laser beam size at the target, further limiting laser target irradiance and effectiveness over long distances.