Modeling and Characterization of Wideband Communications Via Narrowband Channels Using Direct Modulation
Jacob James Adams
Project runs from 09/15/2016 to 09/14/2019
Long distance communications rely on HF, VHF, and UHF wireless systems where wavelengths are over 1 meter long. Conventionally, resonant antennas are used in mobile applications in these bands, due to the large size required for more broadband structures. A resonant antenna in steady state can only effectively transmit a narrow range of frequencies. However, if the antenna’s properties are modulated at a rate on the order of the symbol frequency, then the antenna becomes a time variant system that may circumvent the physical limitations of small antennas. Experiments have indicated that unusually wideband emissions from small antennas are possible, though further study is needed to address the fundamental questions in this area and improve the present understanding of time-varying radiators. The overall scientific goal of this proposal is to establish models and design methodologies for radiating systems with rapidly time-varying properties.