Stavros Georgakopoulos

Prof. Stavros Georgakopoulos

College of Engineering & Computing, Florida International University, Miami, FL 33174, USA
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Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 October 2021 in IEEE Open Journal of Antennas and Propagation
Verified
Journal Article
Open access
SGStavros Georgakopoulos
Stavros Georgakopoulos
Constantinos ZekiosConstantinos Zekios
Constantinos Zekios
AKAbdul-Sattar Kaddour
Abdul-Sattar Kaddour
MHMuhammad Hamza
Muhammad Hamza
ABAkash Biswas
Akash Biswas
RLRobert Lang
Robert Lang
The field of foldable and physically reconfigurable antennas has recently attracted significant interest from diverse scientific communities, including researchers on antennas, material science, mechanical engineering and numerical modeling. Deployable, packable and multifunctional systems are very important for many applications, including satellite communications, UAVs, CubeSats as well as airborne and spaceborne communication systems. Foldable and physically reconfigurable antennas, particularly origami-based antennas, can provide new capabilities for the aforementioned applications. In this work, we present emerging research on foldable and physically reconfigurable antennas. Such antennas morph their shape to adapt and reconfigure their EM performance (e.g., frequency of operation, bandwidth, polarization, beamwidth, etc.). Also, origami antennas provide ultra-compact stowage, easy deployment, reduced weight, enhanced EM performance and multifunctional utility.
17 May 2016 in IEEE Transactions on Industrial Electronics
Verified
Journal Article
Open access
HHHao Hu
Hao Hu
SGStavros Georgakopoulos
Stavros Georgakopoulos
Novel multiband and broadband wireless power transfer (WPT) systems based on conformal strongly coupled magnetic resonance (CSCMR) are presented in this paper. An analytical model for CSCMR systems is developed in order to study their performance. Optimal multiband and broadband CSCMR systems are designed and their performance is validated using simulations and measurements. A broadband CSCMR system, which exhibits seven times broader bandwidth than conventional SCMR and CSCMR systems operating at the same frequency, is designed and prototyped.
3 March 2017 in IEEE Transactions on Antennas and Propagation
Verified
Journal Article
Open access
SYShun Yao
Shun Yao
XLXueli Liu
Xueli Liu
SGStavros Georgakopoulos
Stavros Georgakopoulos
A two-arm Nojima origami conical spiral antenna (CSA) is designed. The antenna is based on the origami Nojima wrap pattern that enables the antenna to morph from a planar dipole to a conical spiral. The design equations of the Nojima origami CSA are presented and its performance is studied using simulations and measurements. The reflection coefficient, input impedance, gain, and axial ratio of this antenna are investigated over a wide frequency band. The radiation patterns of this antenna are also examined. A prototype of an origami Nojima CSA with 1.5 turns is manufactured and measured.
7 December 2020 in IEEE Access
Verified
Journal Article
Open access
AKAbdul-Sattar Kaddour
Abdul-Sattar Kaddour
CVCarlos Alberto Velez
Carlos Alberto Velez
MHMuhammad Hamza
Muhammad Hamza
NBNathan C. Brown
Nathan C. Brown
CYCollin Ynchausti
Collin Ynchausti
SGStavros Georgakopoulos
Stavros Georgakopoulos
An origami-based foldable and reconfigurable Reflectarray Antenna (RA) with multiple apertures is proposed for CubeSat applications. The proposed configuration consists of a central RA embedded in folding panels using Lamina Emergent Torsional (LET) joints based on compliant mechanisms. Depending on the folding direction of these panels (forward or backward), a new RA aperture is formed. The proposed RA along with its folding panels and hinges is fabricated using only a single PCB. A prototype of such an RA with two foldable panels is fabricated and measured. This RA operates in the Ku-band at 16 GHz and provides two pencil beams pointing at (θ = 30°, φ = 0°) and (θ = -30°, φ = 0°), and a dual-beam pointing at (θ = +27°, φ = 0°) and (θ = -29°, φ = 0°). The proposed RA provides a gain of 25 dB and 19 dB in its single- and dual-beam operations, respectively. For CubeSat applications, the key advantages of this RA are its small stowed volume, reconfigurable EM performance, beamsteering capabilities, monolithic construction, low fabrication cost, and reduced complexity.
13 March 2024 in IEEE Access
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Journal Article
Open access
RKRayhan Khan
Rayhan Khan
Constantinos ZekiosConstantinos Zekios
Constantinos Zekios
SBShubhendu Bhardwaj
Shubhendu Bhardwaj
SGStavros Georgakopoulos
Stavros Georgakopoulos
This study investigates the use of deep learning techniques for building a generalized surrogate model that can accurately and very efficiently predict antenna performance parameters. Notably, we focus on applications where a substantial amount of simulation time is required and prior data is available for deep learning use. Specifically, for these applications, we introduce deep learning models that efficiently and reliably model the near-field of the antenna. These models, in turn, accurately predict far-field properties and essential antenna metrics, such as the reflection coefficient. To demonstrate the efficiency of our method, the widely used rectangular patch antenna is considered, encompassing variations in several important geometrical parameters, dielectric constant, and frequency. Based on our results, the proposed model, once trained, is over 200 times faster than conventional full-wave simulations with a nominal average root mean square error (RMSE) of 0.0174 in predicting all the necessary antenna parameters, such as resonant frequency, radiation pattern, and directivity.
11 June 2019 in IEEE Transactions on Antennas and Propagation
Verified
Journal Article
Open access
YSYousuf Shafiq
Yousuf Shafiq
JGJohn S. Gibson
John S. Gibson
HKHyun Kim
Hyun Kim
CACedric P. Ambulo
Cedric P. Ambulo
TWTaylor Ware
Taylor Ware
SGStavros Georgakopoulos
Stavros Georgakopoulos
A new passive RFID temperature sensor is presented for monitoring the temperature of the surrounding environment of perishable goods, such as, foods and medicines, in the cold supply chain. Specifically, this sensor self-tunes between 902 MHz and 928 MHz, operating in the RFID UHF band, as the temperature rises or falls beyond a certain threshold. The novelty of this passive sensor is its ability to operate through multiple high/low temperature cycles. The design consists of a planar dipole antenna with a customized Integrated T-match Network (ITMN) that is actuated above a ground plane. The actuation shifts the operating frequency and is controlled by Liquid Crystal Elastomers (LCEs), which are programmable and reversible temperature dependent polymers. As a result, our design can be reconfigured to operate at various temperature ranges for which the LCE is designed to operate. Analysis is performed to examine the performance of the proposed sensor near practical items and when it is in close-proximity to an additional sensor with varying orientation. Finally, the sensor’s performance was validated through full-wave simulations using ANSYS HFSS and measurements. Both the simulation and measurements agreed well with theory.