Defense Advanced Research Projects AgencyTagged Content List

Electromagnetic Spectrum and Bandwidth

Novel concepts and technologies for maximizing use of the electromagnetic spectrum

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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.
Reliable wireless communications today requires careful allocation of specific portions of the electromagnetic spectrum to individual radio networks. While pre-allocating spectrum is effective in benign environments, radios remain vulnerable to inadvertent interference from other emitters and intentional jamming by adversaries.
In the 1940s, researchers learned how to precisely control the frequency of microwaves, which enabled radio transmission to transition from relatively low-fidelity amplitude modulation (AM) to high-fidelity frequency modulation (FM). This accomplishment, called microwave frequency synthesis, brought about many advanced technologies now critical to the military, such as wireless communications, radar, electronic warfare, atomic sensors and precise timing.
Since its inception in 1992, DARPA’S Microsystems Technology Office (MTO) has helped create and prevent strategic surprise through its investments in compact microelectronic components such as microprocessors, microelectromechanical systems (MEMS), and photonic devices. MTO’s revolutionary work applying these advanced capabilities in areas such as wide-band gap materials, phased array radars, high-energy lasers and infrared imaging have helped the United States establish and maintain technological superiority for more than two decades.