We are pleased to announce that Prof. Marinos N. Vouvakis from University of Massachusetts Amherst will present to the Microwave Theory & Techniques and the Antennas & Propagation Societies On April 19 at 6pmAbstract:
The two prevailing trends in modern communication and sensing system technologies are increased information throughput or functionality, and smaller sizes. From the physical-layer electronics perspective such as RF/microwave engineering, these trends translate into hardware with wider bandwidths and higher frequencies of operation. Yet, when it comes to the design of antenna arrays, that are necessary in every wireless communications, stand-off sensing or electronic countermeasure, these treads are in direct conflict with one another. Ultrawideband (UWB) phased arrays are significantly more challenging to design and build than their narrowband counterparts, whereas manufacturability constraints above X-band severely limit the effectiveness of bandwidth enhancement methods. These technical challenges are reflected in the skyrocketing price-tags of extremely high frequency (EHF) UWB arrays, and their limited use to select military or security applications.
Established UWB phased array technologies such as the Vivaldi array, or the fragmented aperture array or Monk’s current sheet array are either too complicated to build at EHFs, or require performance-limiting feeding methods to integrate with the rest of the phased array system, or cannot be easily installed or maintained due to lack of aperture modularity. This seminar will introduce a novel low-cost UWB phased array, the planar ultrawideband modular antenna (PUMA) that overcomes all these limitations. The PUMA array is extremely simple, making it easy to build with standard low-cost microwave fabrication techniques even above Ku-band, the key comes from its novel direct-feeding scheme that avoids altogether external baluns and elaborate feed-line shielding without performance degradation. Moreover, the carefully laid-out PUMA aperture allows for modular manufacturing with tiled assemble, leading to certain cost, installation, maintenance and robustness benefits.
After a brief introduction in ultrawideband/multifunctional systems and phased arrays, the talk will focus on the basic PUMA array topology, variations, principles of operation and modeling, and design and manufacturing approaches. The design, fabrication and measurements of an exemplary 7-21GHz PUMA design will be used to concretely demonstrate the technology. Several newer computational prototypes will be presented that operate at higher than 6:1 bandwidth. Important phased array aspects such as impedance matching (VSWR), coupling, radiation pattern, wide angle scanning, polarization purity, and fabrication cost will be used to scrutinize the quality of the designs. Time permitting, a short glimpse of the advanced in-house numerical modeling techniques, used to design the full finite PUMA array will be given.
Bio:
Dr. Marinos N. Vouvakis (S'99, M’05) is an Associate Professor of Electrical and Computer Engineering (ECE) at the University of Massachusetts Amherst, where he conducts research and teaching in the areas of microwave and antenna engineering, and computational electromagnetics. Dr. Vouvakis received the Diploma degree in ECE from the Democritus University of Thrace (DUTH), Xanthi, Hellas, in 1999, he holds a M.S. from Arizona State University (ASU), Tempe, AZ and a PhD from The Ohio State University (OSU), Columbus OH, both in ECE. Since 2005 he is with the UMass ECE faculty as a member of the Center for Advanced Sensor and Communication Antennas (CASCA) and the Antennas and Propagation Laboratory (APLab). His main research interests are in computational electromagnetics (CEM), where he is known for his contributions on domain decomposition methods, finite element methods, fast integral equation methods, hybrid methods, and model order reduction, all in the context of antennas, electromagnetic scattering, microwave devices, EMC/EMI and optical lithography modeling. Recently he started working on experimental research in antennas and the design of ultrawideband and low-profile phased arrays.
Meeting will be held at MIT Lincoln Laboratory A-Café, 244 Wood Street, Lexington, MA. For directions please see: http://www.ll.mit.edu/about/map.html
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