Elena Semouchkina
Dr. Elena Semouchkina's research interests are focused on new engineered dielectric materials and structures for the next generation of cell phones, medical imaging systems, and radar applications. The critical requirement for faster wireless data transmission has prompted development of new materials and components for high frequencies. Elena's research integrates fundamental study of electromagnetic wave interaction with non-uniform media, approbation of new ideas in engineering hybrid ceramic materials, and development of innovative devices vital for advanced wireless communication systems. The goal of her research is to find new ways to enhance functionality and reduce size of the devices by affecting wave propagation processes in their circuitry through integration diverse dielectric and magnetic materials in the design. Recent achievements in low-temperature co-fired ceramics (LTCC) technology open up the opportunities to co-process diverse ceramics, which makes the approaches feasible.
(LEFT) Electric field distribution for the 3/2 Λ resonant mode in a microstrip open-loop resonator: "compression" of the loaded wavelengths is well seen, and (RIGHT) (4.1 x 5.6) mm2 microstrip band-pass filter utilizing high-permittivity BZT inclusions in low-permittivity LTCC substrate.
She recently received the NSF ADVANCE Fellows Award for her project "Materials Integration Concepts for Electronic and Photonic Devices." The goal of the ADVANCE program is to increase the participation of women in science and engineering through the advancement of women in academic careers. Fellows Awards enable individuals who demonstrate high potential, to develop active, full-time, independent careers at institutions of higher learning, providing for three-year funding to support their research and educational activities. Only 20 to 40 Fellows Awards distributed through all science and engineering fields supported by NSF are given annually nationwide. The NSF review panel regarded Elena's project as an excellent and outstanding one, capable to advance knowledge at the interface of the physics, material science and electrical engineering disciplines.
Her research is based on full-wave electromagnetic analysis performed by using the Finite Difference Time Domain (FDTD) method. As a time-domain Maxwell's equation solver, this method provides a space/time microscope for observation, with submicron/subpicosecond resolution, the dynamics of electromagnetic waves propagating inside the structures. The FDTD codes developed at the Electromagnetic Communication Laboratory led by Prof. R. Mittra at the Department of Electrical Engineering are used for simulations. Prototypes are fabricated and measured at the Smart Materials Integration Laboratory and Microwave Laboratory, respectively. In afddition, unique measurements of the electromagnetic near fields are conducted at the Institute of Radiophysics in Ukraine.
(LEFT) Prototype meta-material with a 5x5 array of dielectric resonators, 3mm in diameter, within a glass bonded alumina matrix, and (RIGHT) beam propagation through substrate with embedded metamaterial prism, f=16.9 GHz
In particular, innovative filters, antennas, phase shifters and meta-materials are being developed. For example, local reactive loading of microstrip filters by using high permittivity dielectric inclusions or layers, was found to be very efficient for resonant mode "compression". Utilizing implants with the dielectric permittivity of 74 in the LTCC substrates with the permittivity of 7.8 allowed for decreasing microstrip filter size from (20 x 40) mm2 down to (4.1 x 5.6) mm.2 Materials integration concepts are also applied for designing periodic dielectric structures, which exhibit properties that are not possible in single-phase natural materials. Recently, periodic meta-materials have demonstrated very unusual properties such as backward wave propagation or left-hand behavior. Dr. Semouckina has invented a new all-dielectric meta-material, which employs a periodic array of high-permittivity dielectric resonators embedded into lower-permittivity matrix instead of planar metal rings used in conventional backward wave materials. The proposed dielectric structures are fundamentally different than photonic band gap (PBG) crystals, utilizing Bragg-scattering, since they perform due to cooperative phenomena based on electromagnetic resonances in lattice cells.
High permittivity dielectric resonators are linked together in a periodic structure and become electromagnetically coupled under resonant conditions. Initial results demonstrate that dielectric meta-materials can be designed and fabricated for microwave, mm-wave and THz frequencies and that the interplay between local resonator mode symmetry and global lattice symmetry provides for intriguing properties, such as frequency dependent dispersion of radiating beams, negative refraction and formation of electric and magnetic laminar superstructures. A broad group of new architectures can now be based on this concept, in which dielectric resonances in periodic structures are tailored for novel microwave and mm-wave applications, such as antennas with beam steering, filter devices, multiplexers, phase shifters or electro-optical modulators.
(TOP LEFT) Field distribution within resonant dielectric meta-material at non-resonant frequency, (TOP RIGHT) examples of electric field coupling at resonant conditions in the vicinity of the first higher order mode, and formation of (BOTTOM LEFT) electric and (BOTTOM RIGHT) magnetic laminar superstructures at resonant conditions for the first and second lowest modes, respectively: neighbouring stripes in phase patterns have 180° phase difference.
BIO
She received her M.S. degree in Electrical Engineering and her Candidate of Science degree in Physics & Mathematics, both from Russia. Her research in Russian academic research centers in Siberia and St. Petersburg was concentrated on the study of semiconductor materials and devices and on the development of novel infrared photodetectors. She entered the graduate school of the Pennsylvania State University in fall 1997 and received her Ph.D. degree in Materials in spring 2001. Her thesis "FDTD Analysis of Microwave Resonant Structures with Dielectric Substrates" received the MRI award for the best Ph.D. thesis in 2001. She has been working at the Center for Dielectric Studies of the Materials Research Institute since 1997, first, as a graduate research assistant and then, as a postdoctoral scholar. During this period she has published more than twenty papers and has annually presented the results of her work at the International Symposia and Conferences. Her future plans include incorporaion of the knowledge gained from the research activities into a new interdisciplinary course, in which materials science, solid-state physics, and electrical engineering concepts will be combined to tackle future problems in wireless communications. The work on this course is a part of the fellowship supported by NSF.
