Parity Time-reversal Duality (PTD ) Symmetric Structures


Parity Time-reversal Duality (PTD ) Symmetric Structures

Wed, 08/02/2023 - 13:30 to 15:00


Iram Nadeem
University of Siena, Italy

Topological Edge modes (TPEMs) are the electromagnetic (EM) equivalent of the edge states in the integer quantum hall effect that occurs due to topological phase transitions of matter, the discovery at the origin of the Nobel Prize awarded to Thouless, Haldane and Kosterlitz in 2016. The EM extension of TPEMs, originally found at atomic level, was then moved to plasmonics and microwaves areas, opening new and unexpected opportunities for innovation. The novel aspect of TPEMs is that they can be "protected against backscattering" thus, enabling a wave-guiding not affected by reflections due to disorder, imperfections, obstacles, or deformations of the propagation path. TPEMs protection normally requires non-reciprocal elements. However, recent research has shown that it can be also generated by reciprocal materials. A class of structures supporting modes protected against backscattering is the one of PTD-symmetric systems, i.e, systems invariant under the combination of the parity (P), time reversal (T) and duality (D) operators. This condition can be also fulfilled by passive and lossless reciprocal structures, provided that the electromagnetic properties become dual in Babinet sense upon mirroring with respect to a certain plane. If this condition is verified, the system is capable of supporting propagation without backscattering, i.e. the guiding structures, even if not rigorously unidirectional in topological sense, are intrinsically matched even in the presence of discontinuities if also these latter are PTD-symmetry complaint.In this talk, the practical realization of dual volumetric materials will be focused where a homogeneously filled guiding structure, PTD-symmetry condition reduces the duality of the boundary conditions (BCs), which can be implemented through metasurfaces (MTSs). For instance, a possible PTD-symmetric structure consists of the combination of two dual parallel plate waveguides with one perfect electric conductor (PEC) and one perfect magnetic conductor (PMC) wall.


Iram Nadeem is PhD thesis defending student in Electromagnetics Innovation Joint Lab with Huawei, University of Siena Italy. She is actively working on higher order symmetry type: Parity time-reversal duality (PTD) Symmetric structures. She is the recipient of “TICRA-EurAAP Grants-2022” and “Dr. Mojgan Daneshmand Grant-2022” based on her academic profile. She was visiting researcher in University Carlos III Madrid, Spain to investigate Gap-wave technology with PTD symmetry. She has received her M.Eng degree in Information and Communication Engineering from Chosun University in South Korea at 2018 on full time scholarship from Korean Government. She had worked as researcher in the Department of Information and Communication Engineering, Chosun University from 2018 to 2019. Her research project was ultra-wide band antenna design for location detection application. Iram also had M.S. in Telecommunication Engineering (Major: Optical Fiber Communication) and B.S. in Electrical Engineering (Major: Power Systems) from the University of Engineering and Technology (UET) Taxila, Pakistan in 2014 and 2010 respectively. Moreover, she had also worked as Lecturer and Lab Engineer in different engineering institutes of Pakistan during 2011 to 2015. Her research interests include PTD symmetric structures, Gap-wave technology, UWB, and MIMO antenna design