Panagiotis Theofanopoulos

Panagiotis Theofanopoulos
Arizona State University | ASU · Department of Electrical Engineering

Electrical and Computer Engineering, Dip., M.Sc.

About

40
Publications
4,008
Reads
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178
Citations
Citations since 2017
31 Research Items
171 Citations
2017201820192020202120222023010203040506070
2017201820192020202120222023010203040506070
2017201820192020202120222023010203040506070
2017201820192020202120222023010203040506070
Additional affiliations
September 2013 - December 2015
Democritus University of Thrace
Position
  • Master Student/ Research Assistant
Education
October 2013 - December 2015
Democritus University of Thrace
Field of study
  • Electrical and Computer Engineering
September 2008 - September 2013
Democritus University of Thrace
Field of study
  • Electrical and Computer Engineering

Publications

Publications (40)
Article
Full-text available
This study presents findings in the terahertz (THz) frequency spectrum for non-contact cardiac sensing applications. Cardiac pulse information is simultaneously extracted using THz waves based on the established principles in electronics and optics. The first fundamental principle is micro-Doppler motion effect. This motion based method, primarily...
Article
Full-text available
Reconfigurable intelligent surfaces (RISs) have promising coverage and data-rate gains for wireless communication systems in 5G and beyond. Prior work has mainly focused on analyzing the performance of these surfaces using simulations or lab-level prototypes. To draw accurate insights about the actual performance of these systems, this paper develo...
Preprint
Full-text available
This study presents findings at Terahertz (THz) frequency band for non-contact cardiac sensing application. For the first time, cardiac pulse information is simultaneously extracted using THz waves based on the two established principles in electronics and optics. The first fundamental principle is micro-Doppler (mD) motion effect, initially introd...
Preprint
Full-text available
Reconfigurable intelligent surfaces (RISs) have promising coverage and data rate gains for wireless communication systems in 5G and beyond. Prior work has mainly focused on analyzing the performance of these surfaces using computer simulations or lab-level prototypes. To draw accurate insights about the actual performance of these systems, this pap...
Preprint
div> We present novel multi-bit unit-cell topologies for reconfigurable reflective surfaces –RRSs– (e.g., reflectarray antennas) with compact designs for millimeter-wave and terahertz (mmWave/THz) applications. Typically, mmWave/THz RRSs utilize one or multiple single-pole-single-throw (SPST) switches leading to single- or dual-bit modulated surf...
Preprint
div> We present novel multi-bit unit-cell topologies for reconfigurable reflective surfaces –RRSs– (e.g., reflectarray antennas) with compact designs for millimeter-wave and terahertz (mmWave/THz) applications. Typically, mmWave/THz RRSs utilize one or multiple single-pole-single-throw (SPST) switches leading to single- or dual-bit modulated surf...
Article
Full-text available
Due to a production error, in the original article [1] , Fig. 5 was incorrectly published. We apologize for this error. The correct figure, with the corresponding caption, is shown below.
Preprint
We present a method for the mitigation of quantization lobes in single-bit reconfigurable reflective surfaces (RRSs). Typically, RRSs are planar beamforming structures consisting of hundreds or thousands of antennas with integrated tunable switches. Under plane-wave illumination, single-bit RRSs suffer from undesired side lobes or quantization lobe...
Preprint
We present a method for the mitigation of quantization lobes in single-bit reconfigurable reflective surfaces (RRSs). Typically, RRSs are planar beamforming structures consisting of hundreds or thousands of antennas with integrated tunable switches. Under plane-wave illumination, single-bit RRSs suffer from undesired side lobes or quantization lobe...
Article
Full-text available
We present an analysis of graphene-loaded transmission line switches for sub-millimeter wave and terahertz applications. As such, we propose equivalent circuit models for graphene-loaded coplanar waveguides and striplines and examine the switching performance under certain parameters. Specifically, we identify the optimum design of graphene switche...
Preprint
We present an analysis of graphene loaded transmission line switches. Namely, we propose equivalent circuit models for graphene loaded coplanar waveguides and striplines and examine the switching performance under certain design parameters. As such, the models account for the distributed effects of electrically-large shunt switches in coplanar wave...
Preprint
We present an analysis of graphene loaded transmission line switches. Namely, we propose equivalent circuit models for graphene loaded coplanar waveguides and striplines and examine the switching performance under certain design parameters. As such, the models account for the distributed effects of electrically-large shunt switches in coplanar wave...
Article
Full-text available
We present a method for the mitigation of quantization lobes in single-bit reconfigurable reflective surfaces (RRSs). Typically, RRSs are planar beamforming structures consisting of hundreds or thousands of antennas with integrated tunable switches. Under plane-wave illumination, single-bit RRSs suffer from undesired side lobes or quantization lobe...
Article
The authors present a fabrication process for the development of high-frequency (>30 GHz) on-wafer graphene devices with the use of titanium sacrificial layers. Graphene patterning requires chemical processes that have deleterious effects on graphene resulting in very low yield. The authors prevent delamination of the delicate graphene from the sub...
Article
Full-text available
We present a novel imaging method for compact, low-profile imagers in millimeter wave (mmW) and terahertz (THz) frequencies. The method borrows the principles of computerized tomography (CT) to generate 2D or 3D high-resolution images using simplified RF-front-ends. To perform imaging the proposed scheme implements the projection-slice theorem. Spe...
Article
Full-text available
We propose a novel technique for efficient and robust modeling of multistatic, multi-dimensional, large-format millimeter-wave/terahertz (mmW/THz) imaging systems. The proposed method significantly reduces the necessary computational resources for the design of electrically large systems of multiple sensors that acquire multi-frequency images, such...
Conference Paper
Full-text available
In this study a novel THz system is presented for 2D or 3D radar imaging. The system implements a Computerized Tomography's (CT's) algorithm that records the Radon Transform (RT) of an object and reconstructs the image using the Inverse Radon Transform (IRT). As such, the imaging system is comprised of a simple linear antenna that significantly sim...
Conference Paper
Full-text available
Eigenanalysis of canonically shaped structures served as an indispensable tool the conception and establishment of a plethora of electromagnetic structures from filters to cavities and antennas. However, the recent evolution of radio systems and wireless communications ask for the design of multifunctional rf front-ends in compact form and conforma...
Article
Full-text available
The aim of this paper is the investigation of nonreciprocal phenomena in anisotropically loaded 2-D periodic structures. For this purpose, our well-established 2-D curvilinear finite difference frequency domain method is combined with periodic boundary conditions and extended toward the eigenanalysis of periodic structures loaded with both isotropi...
Conference Paper
Full-text available
A two dimensional Finite Difference Frequency Domain (2D-FDFD) eigenanalysis of an array consisting of periodically located strips printed on axially magnetized ferrite film is presented. The main interest in these structures arises from our previous study which revealed their support of backward surface and possibly backward leaky waves. Moreover...
Conference Paper
Full-text available
The eigenanalysis of periodic stuctures is presented herein by extending our previous two – dimensional curvilinear frequency domain finite difference domain (FDFD) toward the eigenanalysis of open/radiating periodic structures. Initially, the open/radiating structures are simulated using the Perfectly Matched Layer (PML), while later Mur’s Absorbi...
Conference Paper
Full-text available
Computing of wave propagation and radiation through periodic band gap structures and their unique electromagnetic features attracted a huge research interest during the last decades. These features enabled the development of novel metamaterials and were exploited in frequency selective surfaces, phased arrays and numerous electromagnetic bandgap ap...
Conference Paper
Full-text available
Most scientific applications tend to have a very resource demanding nature and the simulation of such scientific problems often requires a prohibitive amount of time to complete. Distributed computing offers a solution by segmenting the application into smaller processes and allocating them to a cluster of workers. This model was widely followed by...
Conference Paper
Full-text available
An eigenanalysis of an array of periodically located wires covered with axially magnetized ferrites is presented. The interest in this structure stems from our previous study which revealed that such a wire may support backward surface and possibly backward leaky waves. These possibilities are examined herein by using our two - dimensional curvilin...
Conference Paper
Full-text available
An eigenanalysis of an array of periodically located wires covered with axially magnetized ferrites is presented. The interest in this structure stems from our previous analytical study which revealed that such a wire may support backward surface and possibly backward leaky waves. It is thus expected that a periodic array of these ferrite loaded wi...
Conference Paper
The aim of this study is to investigate the possible negative refractive index phenomena exhibited by a periodic structure consisting by cylindrical wires covered with axially magnetized ferrite. The inherent negative permittivity of the periodic wires along with the negative permeability of the ferrite result to a tunable artificial negative refra...

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Projects

Projects (2)
Archived project
The scope of this project is the development of Electromagnetic simulation and design tools for digitally controlled and multifunctioning RF-microwave stages and subunits which will retain characteristics-specification supporting “Software Defined (SDR) and cognitive Radios (CR)”, while they will be capable of a conformal incorporation to the hosting platforms.
Project
The goal of the project is to create low profile imaging sensors array on the 100-3000 GHz regime. These arrays could be used for biomedical, security, space and other imaging applications.