Electromagnetic Spectrum and Bandwidth

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 A-to-I Look-Through Program will fundamentally improve the operational bandwidth, linearity, and efficiency of electronic systems where the objective is to receive and transmit information using electromagnetic (radio) waves under extreme size/weight/power and environmental conditions required for DoD applications. This will be achieved by developing new electronic processing subsystems methods and architectures based on new understandings of mathematical principles and embedded signal processing. This program will develop ultra-wideband digital RF receivers based on A-to-I converter (AIC) technology.

Conventional analog-to-digital converters (ADCs) are fundamentally limited by timing jitter in the sampling source, forcing a trade-off between bandwidth and resolution. As a result, radio frequency (RF) systems are typically designed with narrow-bandwidth channels. These engineering constraints present problems when faced with broadband signals and ultra-short pulses. At high carrier frequencies, RF systems are further limited by the tuner that must mix down to baseband for electronic digitization.

Dr. Yiftach Eisenberg is the deputy director of the Microsystems Technology Office (MTO). In that role, Dr. Eisenberg helps set the strategic vision for the office, recruits program managers (PMs) who are leaders in their respective fields, and provides the oversight and guidance required to empower the PMs to drive the creation of breakthrough technology for national security.