Dennis Prather, Engineering Alumni Professor
Ultra-Wideband Antenna Design
- Silicon Photonics
- Ultra-wideband Conformal Antennas
- Passive Millimeter-wave Imaging
- High-Frequency Optical Modulators and RF Photonic Integration
Office: Evans 108
Our work in this field is geared at developing conformal, low profile, and ultra-wideband (UWB) phased arrays that are optically fed and phased controlled. This work is motivated by the increased demand to combine various RF applications into a single RF antenna, thus having a multi-functional system that span several octaves of bandwidth. This is particularly well suited for applications such as radar, ultra-fast communication, RF sensing, and passive RF imaging systems.
The focus of this work is on the development and integration of the corresponding RF and photonic components into UWB arrays, which becomes extremely challenging particularly at higher frequencies. To address these issues, our group uses optically addressed phased arrays, which offer tremendous advantages, such as low SWaP (size, weight, and power), immunity to EMC, and extreme frequency agility.
Current research efforts are being conducted on the development of widely tunable RF frequency synthesizers, optical phase control and feed networks, low profile and UWB tightly-coupled-array (TCA) antennas, and antenna coupled high-speed and high-power down-conversion photonic module integration.
Recently we have demonstrated the optical generation of an UWB RF source that spans 1-100GHz with a 1Hz linewidth over this entire range. This is achieved by coherently mixing two off-set optical tones onto a photodiode to produce the request down-converted RF signal.
Subsequently, the resulting RF signal is used to feed a TCA antenna. However, to phase-control the antenna array we use the optical domain, where a novel phase control architecture has been developed using electro-optic modulators. This proposed approach offers many technical advantages over more conventional RF phased arrays, including: 1) low dispersion and transmission loss, 2) environmental phase noise cancellation, 3) light weight and flexible distribution, (4) ultra-wideband operation, and (5) large scalability.
G. J. Schneider, J. Murakowski, C. A. Schuetz, S. Shi, and D. W. Prather, "Radio-frequency signal generation system with seven octaves of continuous tuning," Nature Photonics, Vol. 7, pp. 118-122, 2013.
S. Shi, J. Bai, Y. Zhang, G. Schneider, and D. W. Prather, "Ultra-wideband optically addressed transmitting phased array", IEEE Antenna Propagation Symposium, Orlando, FL, 2013.
J. Bai, S. Shi and D.W. Prather, "Modified compact antipodal Vivaldi antenna for 4-50GHz UWB application", IEEE Transactions on Microwave Theory and Techniques and Antenna Propagation joint special issue on Ultra-Wideband Technology, Vol. 59, No. 4, pp.1051-1057, 2012.
S. Shi, J. Bai, G. J. Schneider, and D. W. Prather, "Optical feed network and ultra-wideband phased array", IEEE Photonics Conference, San Francisco, Sep. 2012.