Defense Advanced Research Projects AgencyTagged Content List

Electromagnetic Spectrum and Bandwidth

Novel concepts and technologies for maximizing use of the electromagnetic spectrum

Showing 105 results for Spectrum RSS
03/06/2014
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.
04/02/2014
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.
04/22/2014
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.
05/28/2014
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.
06/30/2014
Many existing compact, high-data-rate millimeter-wave wireless communications systems use integrated circuits (ICs) made with gallium arsenide (GaAs) or gallium nitride (GaN). These circuits provide high power and efficiency in small packages but are costly to produce and difficult to integrate with silicon electronics that provide most other radio functions. Silicon ICs are less expensive to manufacture in volume than those with gallium compounds but until now have not demonstrated sufficient power output and efficiency at millimeter-wave frequencies used for communications and many other military applications, such as radar and guidance systems.