Pietro Bia | Politecnico di Bari (original) (raw)
Papers by Pietro Bia
2022 61st FITCE International Congress Future Telecommunications: Infrastructure and Sustainability (FITCE), Sep 29, 2022
2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017
A novel two-dimensional (2-D) finite-difference time-domain algorithm for modeling ultrawideband ... more A novel two-dimensional (2-D) finite-difference time-domain algorithm for modeling ultrawideband pulse propagation in arbitrary dispersive soils is presented. The soil dispersion is modeled by general power law series representation, accounting for multiple higher order dispersive relaxation processes and ohmic losses, and incorporated into the FDTD scheme by using the fractional derivative operators. The dispersive soil parameters are obtained by fitting the reported experimental data. Moreover, dedicated uniaxial perfectly matched layer for matching dispersive media are derived and implemented in combination with the basic time-marching scheme. Examples are given to verify the numerical solution and demonstrate its applications. The proposed technique features a significantly enhanced accuracy in the solution of complex electromagnetic propagation problems typically encountered in geoscience applications.
Nanoscale Networking and Communications Handbook, 2019
2022 7th International Conference on Smart and Sustainable Technologies (SpliTech)
Electronics
The use of fractional derivatives and integrals has been steadily increasing thanks to their abil... more The use of fractional derivatives and integrals has been steadily increasing thanks to their ability to capture effects and describe several natural phenomena in a better and systematic manner. Considering that the study of fractional calculus theory opens the mind to new branches of thought, in this paper, we illustrate that such concepts can be successfully implemented in electromagnetic theory, leading to the generalizations of the Maxwell’s equations. We give a brief review of the fractional vector calculus including the generalization of fractional gradient, divergence, curl, and Laplacian operators, as well as the Green, Stokes, Gauss, and Helmholtz theorems. Then, we review the physical and mathematical aspects of dielectric relaxation processes exhibiting non-exponential decay in time, focusing the attention on the time-harmonic relative permittivity function based on a general fractional polynomial series approximation. The different topics pertaining to the incorporation o...
2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring), 2019
Electroporation is a non-thermal electromagnetic phenomenon widely used in medical diseases treat... more Electroporation is a non-thermal electromagnetic phenomenon widely used in medical diseases treatment. Different mathematical models of electroporation have been proposed in literature to study pore evolution in biological membranes. This paper presents a nonlinear dispersive multiphysic model of electroporation in irregular shaped biological cells in which the spatial and temporal evolution of the pores size is taken into account. The model solves Maxwell and asymptotic Smoluchowski equations and it describes the dielectric dispersion of cell media using a Debye-based relationship. Furthermore, the irregular cell shape has been modeled using the Gielis superformula. Taking into account the cell in mitosis phase, the electroporation process has been studied comparing the numerical results pertaining the model with variable pore radius with those in which the pore radius is supposed constant. The numerical analysis has been performed exposing the biological cell to a rectangular electric pulse having duration of 10mumathrms10\ \mu\mathrm{s}10mumathrms. The obtained numerical results highlight considerable differences between the two different models underling the need to include into the numerical algorithm the differential equation modeling the spatial and time evolution of the pores size.
2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring), 2019
A new class of irregularly shaped dielectric lens antennas with a supershaped microstrip antenna ... more A new class of irregularly shaped dielectric lens antennas with a supershaped microstrip antenna feeder is presented and detailed in this work. The surface of the lens antenna and the feeder shape have been modelled by using the three and two-dimensional Gielis formula, respectively. The antenna design has been carried out by integrating an home-made software tool with the CST Microwave Studio®. The radiation properties of the whole antenna system have been evaluated using a dedicated high-frequency technique based on the tube tracing approximation. Moreover, the effects due to the multiple internal reflections have been properly modeled. The proposed model was applied to study unusual and complex lens antenna systems with the aim to design special radiation characteristics.
2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring), 2019
In this work, a nonlinear dispersive multiphysic model based on Maxwell and asymptotic Smoluchows... more In this work, a nonlinear dispersive multiphysic model based on Maxwell and asymptotic Smoluchowsky equations has been developed to analyze the electroporation phenomenon induced by pulsed electric field on biological cells. The irregular plasma membrane geometry has been modeled by incorporating in the numerical algorithm the Gielis superformula as well as the dielectric dispersion of the plasma membrane has been modeled using the multi-relaxation Debye-based relationship. The study has been carried out with the aim to compare our model implementing a thin plasma membrane with the simplified model in which the plasma membrane is modeled as a distributed impedance boundary condition. The numerical analysis has been performed exposing the cell to external electric pulses having rectangular shapes. By an inspection of the obtained results, significant differences can be highlighted between the two models confirming the need to incorporate the effective thin membrane into the numerical algorithm to well predict the cell response to the pulsed electric fields in terms of transmembrane voltages and pore densities, especially when the cell is exposed to external nanosecond pulses.
Mathematical Problems in Engineering, 2016
The electromagnetic analysis of a special class of 3D dielectric lens antennas is described in de... more The electromagnetic analysis of a special class of 3D dielectric lens antennas is described in detail. This new class of lens antennas has a geometrical shape defined by the three-dimensional extension of Gielis’ formula. The analytical description of the lens shape allows the development of a dedicated semianalytical hybrid modeling approach based on geometrical tube tracing and physical optic. In order to increase the accuracy of the model, the multiple reflections occurring within the lens are also taken into account.
2021 Photonics & Electromagnetics Research Symposium (PIERS), 2021
High Power Microwave (HPM) sources are widely used as signal sources in radar, jammer, and Counte... more High Power Microwave (HPM) sources are widely used as signal sources in radar, jammer, and Counter Improvised Explosive Devices (CIED). Such devices usually are heavy and bulky, characteristics that are in conflict with the small weight and power (SWaP) approach so that it is practically impossible to mount such HPMs on several platforms with reduced spaces (e.g., avionic, UAVs). During the last century, several devices have been proposed, all of them heavy due to the components that they need such as the magnetic material of the Magnetron, Klystron, or Gyrotron. Considering the HPM sources for pulsed applications, the VIRtual CAThode oscillatOR (Vircator) represents the best candidate due to the compact dimension and reduced weight due to the absence of a magnetic source. The signal generated by this HPM device is characterized by a pulsed output power of some GW for a narrow frequency below 10 GHz. In this work, the analysis of the three most used types of Vircator, Axial Vircator, Coaxial Vircator, and Reflex Triode, is reported. A novel anode design and characterization procedure is reported, which led to the analysis of the interaction between electrons and a realistic anode grid.
2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI), 2021
This work presents the design of an ultra-wideband (UWB) dielectric lens for pattern shape contro... more This work presents the design of an ultra-wideband (UWB) dielectric lens for pattern shape control. The lens is meant to be easily installed on a wideband double ridged horn antenna to handle its beam in both elevation and azimuth planes. Specific applications, such as compact interferometric panels and panoramic scanning, require the antenna to instantaneously cover large angular sectors with a reduced physical area. The geometry of the lens has been optimized with an error-weighted quantum particle swarm optimization (EWQPSO) algorithm. The designed lens allows to conveniently guide the phase of the electric field radiated by the horn antenna in order to provide the desired boresight realized gain and half-power beamwidth (HPBW) on the principal planes maintaining high efficiency. Moreover, the lens can be easily realized in additive manufacturing technology, providing a size, weight, power, and cost (SWaP-C) solution. The antenna performance are extremely promising in terms of reflection coefficient, boresight gain, and shape of patterns.
Sensors, 2021
In this paper, the recent progress on sinuous antennas is detailed, focusing the attention on the... more In this paper, the recent progress on sinuous antennas is detailed, focusing the attention on the antenna geometry, dielectric structure, and miniaturization techniques. In the first part, we introduce the basic principles of the frequency-independent antenna, in particular the self-complementary and log-periodic geometries, as well as the antenna geometries, all characterized in terms of angles. The operating principles, main advantages, system design considerations, limits, and challenges of conventional sinuous antennas are illustrated. Second, we describe some technical solutions aimed to ensure the optimal trade-off between antenna size and radiation behavior. To this aim, some special modification of the antenna geometry based on the meandering as well as on the loading with dielectric structures are presented. Moreover, the cavity backing technique is explained in detail as a method to achieve unidirectional radiation. Third, we present a new class of supershaped sinuous ante...
2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, 2020
This paper describes the design approach useful to integrate in the same mechanical structure two... more This paper describes the design approach useful to integrate in the same mechanical structure two functionalities of the Electronic Warfare (EW) environment: Radar-Electronic Support Measurements (RESM) and Communication-Electronic Support Measurements (CESM). The interested architecture provides electro-magnetic and thermo-mechanical solutions to minimize the coupling between the installed antennas and to reduce the Radar Cross Section (RCS) of the whole structure. The proposed system can be installed on several platforms, especially when only a single mast is available for both CESM-RESM, such as new generation patrol vessels, submarines and frigates. Finally the main advantages of the integrated system are: lower costs, simplified installation and modularity.
2015 International Conference on Electromagnetics in Advanced Applications (ICEAA), 2015
In this paper, an accurate finite-difference time-domain (FDTD) scheme for modeling the electroma... more In this paper, an accurate finite-difference time-domain (FDTD) scheme for modeling the electromagnetic pulse propagation in arbitrary dispersive media is presented. The main mathematical drawbacks encountered while solving this class of problems by means of the FDTD technique is the approximation of the fractional derivatives appearing in the time-domain permittivity response pertaining such materials. In order to overcome this issue, the proposed scheme solves the Maxwell's equations directly in the time-domain by using the Riemann-Liouville fractional derivative operator. The feasibility of the proposed method is demonstrated by simulating the ultra-wideband wave propagation in general stratified Raicu dispersive media displaying multiple relaxation times response.
Optical Engineering, 2013
ABSTRACT A novel class of supershaped dielectric lens antennas, whose geometry is described by th... more ABSTRACT A novel class of supershaped dielectric lens antennas, whose geometry is described by the three-dimensional extension of Gielis' formula, is introduced and analyzed. To this end, a hybrid approach based on geometrical and physical optics is adopted in order to properly model the multiple wave reflections occurring within the lens and the relevant impact on the radiation properties of the antenna under analysis. The developed modeling procedure has been validated by comparison with numerical results already reported in the scientific literature and, afterwards, applied to the electromagnetic characterization of a Gielis lens antenna with shaped radiation pattern.
ABSTRACT In this paper, an accurate finite-difference time-domain (FDTD) scheme is proposed for s... more ABSTRACT In this paper, an accurate finite-difference time-domain (FDTD) scheme is proposed for studying electromagnetic pulse propagation in Havriliak-Negami dispersive medium. In traditional FDTD methods, the main drawback occurring in the evaluation of the propagation in a general dispersive media is the approximation of the fractional derivatives appearing in the time-domain permittivity model. In order to face this problem, in this paper we illustrate a FDTD scheme based on the direct solving of the time-domain Maxwell equations by using the Riemann-Liouville operator of fractional differentiation. The feasibility of the proposed method is demonstrated by simulating the transient wave propagation in general bulk and slab dispersive materials.
SAR Image Analysis, Modeling, and Techniques XIV, 2014
ABSTRACT The problems of simulation of bistatic SAR raw data and focusing are studied. A discrete... more ABSTRACT The problems of simulation of bistatic SAR raw data and focusing are studied. A discrete target simulator is described. The simulator introduces the scene topography and compute the integration time of general bistatic configurations providing a means to derived maps of the range and azimuth spatial resolutions. The problem of focusing of bistatic SAR data acquired in a translational-invariant bistatic configuration is studied by deriving the bistatic Point Target Reference spectrum and presenting an analytical solution for its stationary points.
International Journal of Optics, 2012
An optical amplifier based on a tapered fiber and an Er3+-doped chalcogenide microsphere is desig... more An optical amplifier based on a tapered fiber and an Er3+-doped chalcogenide microsphere is designed and optimized. A dedicated 3D numerical model, which exploits the coupled mode theory and the rate equations, is used. The main transitions among the erbium energy levels, the amplified spontaneous emission, and the most important secondary transitions pertaining to the ion-ion interactions have been considered. Both the pump and signal beams are efficiently injected and obtained by a suitable design of the taper angle and the fiber-microsphere gap. Moreover, a good overlapping between the optical signals and the rare-earth-doped region is also obtained. In order to evaluate the amplifier performance in reduced computational time, the doped area is partitioned in sectors. The obtained simulation results highlight that a high-efficiency midinfrared amplification can be obtained by using a quite small microsphere.
2022 61st FITCE International Congress Future Telecommunications: Infrastructure and Sustainability (FITCE), Sep 29, 2022
2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017
A novel two-dimensional (2-D) finite-difference time-domain algorithm for modeling ultrawideband ... more A novel two-dimensional (2-D) finite-difference time-domain algorithm for modeling ultrawideband pulse propagation in arbitrary dispersive soils is presented. The soil dispersion is modeled by general power law series representation, accounting for multiple higher order dispersive relaxation processes and ohmic losses, and incorporated into the FDTD scheme by using the fractional derivative operators. The dispersive soil parameters are obtained by fitting the reported experimental data. Moreover, dedicated uniaxial perfectly matched layer for matching dispersive media are derived and implemented in combination with the basic time-marching scheme. Examples are given to verify the numerical solution and demonstrate its applications. The proposed technique features a significantly enhanced accuracy in the solution of complex electromagnetic propagation problems typically encountered in geoscience applications.
Nanoscale Networking and Communications Handbook, 2019
2022 7th International Conference on Smart and Sustainable Technologies (SpliTech)
Electronics
The use of fractional derivatives and integrals has been steadily increasing thanks to their abil... more The use of fractional derivatives and integrals has been steadily increasing thanks to their ability to capture effects and describe several natural phenomena in a better and systematic manner. Considering that the study of fractional calculus theory opens the mind to new branches of thought, in this paper, we illustrate that such concepts can be successfully implemented in electromagnetic theory, leading to the generalizations of the Maxwell’s equations. We give a brief review of the fractional vector calculus including the generalization of fractional gradient, divergence, curl, and Laplacian operators, as well as the Green, Stokes, Gauss, and Helmholtz theorems. Then, we review the physical and mathematical aspects of dielectric relaxation processes exhibiting non-exponential decay in time, focusing the attention on the time-harmonic relative permittivity function based on a general fractional polynomial series approximation. The different topics pertaining to the incorporation o...
2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring), 2019
Electroporation is a non-thermal electromagnetic phenomenon widely used in medical diseases treat... more Electroporation is a non-thermal electromagnetic phenomenon widely used in medical diseases treatment. Different mathematical models of electroporation have been proposed in literature to study pore evolution in biological membranes. This paper presents a nonlinear dispersive multiphysic model of electroporation in irregular shaped biological cells in which the spatial and temporal evolution of the pores size is taken into account. The model solves Maxwell and asymptotic Smoluchowski equations and it describes the dielectric dispersion of cell media using a Debye-based relationship. Furthermore, the irregular cell shape has been modeled using the Gielis superformula. Taking into account the cell in mitosis phase, the electroporation process has been studied comparing the numerical results pertaining the model with variable pore radius with those in which the pore radius is supposed constant. The numerical analysis has been performed exposing the biological cell to a rectangular electric pulse having duration of 10mumathrms10\ \mu\mathrm{s}10mumathrms. The obtained numerical results highlight considerable differences between the two different models underling the need to include into the numerical algorithm the differential equation modeling the spatial and time evolution of the pores size.
2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring), 2019
A new class of irregularly shaped dielectric lens antennas with a supershaped microstrip antenna ... more A new class of irregularly shaped dielectric lens antennas with a supershaped microstrip antenna feeder is presented and detailed in this work. The surface of the lens antenna and the feeder shape have been modelled by using the three and two-dimensional Gielis formula, respectively. The antenna design has been carried out by integrating an home-made software tool with the CST Microwave Studio®. The radiation properties of the whole antenna system have been evaluated using a dedicated high-frequency technique based on the tube tracing approximation. Moreover, the effects due to the multiple internal reflections have been properly modeled. The proposed model was applied to study unusual and complex lens antenna systems with the aim to design special radiation characteristics.
2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring), 2019
In this work, a nonlinear dispersive multiphysic model based on Maxwell and asymptotic Smoluchows... more In this work, a nonlinear dispersive multiphysic model based on Maxwell and asymptotic Smoluchowsky equations has been developed to analyze the electroporation phenomenon induced by pulsed electric field on biological cells. The irregular plasma membrane geometry has been modeled by incorporating in the numerical algorithm the Gielis superformula as well as the dielectric dispersion of the plasma membrane has been modeled using the multi-relaxation Debye-based relationship. The study has been carried out with the aim to compare our model implementing a thin plasma membrane with the simplified model in which the plasma membrane is modeled as a distributed impedance boundary condition. The numerical analysis has been performed exposing the cell to external electric pulses having rectangular shapes. By an inspection of the obtained results, significant differences can be highlighted between the two models confirming the need to incorporate the effective thin membrane into the numerical algorithm to well predict the cell response to the pulsed electric fields in terms of transmembrane voltages and pore densities, especially when the cell is exposed to external nanosecond pulses.
Mathematical Problems in Engineering, 2016
The electromagnetic analysis of a special class of 3D dielectric lens antennas is described in de... more The electromagnetic analysis of a special class of 3D dielectric lens antennas is described in detail. This new class of lens antennas has a geometrical shape defined by the three-dimensional extension of Gielis’ formula. The analytical description of the lens shape allows the development of a dedicated semianalytical hybrid modeling approach based on geometrical tube tracing and physical optic. In order to increase the accuracy of the model, the multiple reflections occurring within the lens are also taken into account.
2021 Photonics & Electromagnetics Research Symposium (PIERS), 2021
High Power Microwave (HPM) sources are widely used as signal sources in radar, jammer, and Counte... more High Power Microwave (HPM) sources are widely used as signal sources in radar, jammer, and Counter Improvised Explosive Devices (CIED). Such devices usually are heavy and bulky, characteristics that are in conflict with the small weight and power (SWaP) approach so that it is practically impossible to mount such HPMs on several platforms with reduced spaces (e.g., avionic, UAVs). During the last century, several devices have been proposed, all of them heavy due to the components that they need such as the magnetic material of the Magnetron, Klystron, or Gyrotron. Considering the HPM sources for pulsed applications, the VIRtual CAThode oscillatOR (Vircator) represents the best candidate due to the compact dimension and reduced weight due to the absence of a magnetic source. The signal generated by this HPM device is characterized by a pulsed output power of some GW for a narrow frequency below 10 GHz. In this work, the analysis of the three most used types of Vircator, Axial Vircator, Coaxial Vircator, and Reflex Triode, is reported. A novel anode design and characterization procedure is reported, which led to the analysis of the interaction between electrons and a realistic anode grid.
2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI), 2021
This work presents the design of an ultra-wideband (UWB) dielectric lens for pattern shape contro... more This work presents the design of an ultra-wideband (UWB) dielectric lens for pattern shape control. The lens is meant to be easily installed on a wideband double ridged horn antenna to handle its beam in both elevation and azimuth planes. Specific applications, such as compact interferometric panels and panoramic scanning, require the antenna to instantaneously cover large angular sectors with a reduced physical area. The geometry of the lens has been optimized with an error-weighted quantum particle swarm optimization (EWQPSO) algorithm. The designed lens allows to conveniently guide the phase of the electric field radiated by the horn antenna in order to provide the desired boresight realized gain and half-power beamwidth (HPBW) on the principal planes maintaining high efficiency. Moreover, the lens can be easily realized in additive manufacturing technology, providing a size, weight, power, and cost (SWaP-C) solution. The antenna performance are extremely promising in terms of reflection coefficient, boresight gain, and shape of patterns.
Sensors, 2021
In this paper, the recent progress on sinuous antennas is detailed, focusing the attention on the... more In this paper, the recent progress on sinuous antennas is detailed, focusing the attention on the antenna geometry, dielectric structure, and miniaturization techniques. In the first part, we introduce the basic principles of the frequency-independent antenna, in particular the self-complementary and log-periodic geometries, as well as the antenna geometries, all characterized in terms of angles. The operating principles, main advantages, system design considerations, limits, and challenges of conventional sinuous antennas are illustrated. Second, we describe some technical solutions aimed to ensure the optimal trade-off between antenna size and radiation behavior. To this aim, some special modification of the antenna geometry based on the meandering as well as on the loading with dielectric structures are presented. Moreover, the cavity backing technique is explained in detail as a method to achieve unidirectional radiation. Third, we present a new class of supershaped sinuous ante...
2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, 2020
This paper describes the design approach useful to integrate in the same mechanical structure two... more This paper describes the design approach useful to integrate in the same mechanical structure two functionalities of the Electronic Warfare (EW) environment: Radar-Electronic Support Measurements (RESM) and Communication-Electronic Support Measurements (CESM). The interested architecture provides electro-magnetic and thermo-mechanical solutions to minimize the coupling between the installed antennas and to reduce the Radar Cross Section (RCS) of the whole structure. The proposed system can be installed on several platforms, especially when only a single mast is available for both CESM-RESM, such as new generation patrol vessels, submarines and frigates. Finally the main advantages of the integrated system are: lower costs, simplified installation and modularity.
2015 International Conference on Electromagnetics in Advanced Applications (ICEAA), 2015
In this paper, an accurate finite-difference time-domain (FDTD) scheme for modeling the electroma... more In this paper, an accurate finite-difference time-domain (FDTD) scheme for modeling the electromagnetic pulse propagation in arbitrary dispersive media is presented. The main mathematical drawbacks encountered while solving this class of problems by means of the FDTD technique is the approximation of the fractional derivatives appearing in the time-domain permittivity response pertaining such materials. In order to overcome this issue, the proposed scheme solves the Maxwell's equations directly in the time-domain by using the Riemann-Liouville fractional derivative operator. The feasibility of the proposed method is demonstrated by simulating the ultra-wideband wave propagation in general stratified Raicu dispersive media displaying multiple relaxation times response.
Optical Engineering, 2013
ABSTRACT A novel class of supershaped dielectric lens antennas, whose geometry is described by th... more ABSTRACT A novel class of supershaped dielectric lens antennas, whose geometry is described by the three-dimensional extension of Gielis' formula, is introduced and analyzed. To this end, a hybrid approach based on geometrical and physical optics is adopted in order to properly model the multiple wave reflections occurring within the lens and the relevant impact on the radiation properties of the antenna under analysis. The developed modeling procedure has been validated by comparison with numerical results already reported in the scientific literature and, afterwards, applied to the electromagnetic characterization of a Gielis lens antenna with shaped radiation pattern.
ABSTRACT In this paper, an accurate finite-difference time-domain (FDTD) scheme is proposed for s... more ABSTRACT In this paper, an accurate finite-difference time-domain (FDTD) scheme is proposed for studying electromagnetic pulse propagation in Havriliak-Negami dispersive medium. In traditional FDTD methods, the main drawback occurring in the evaluation of the propagation in a general dispersive media is the approximation of the fractional derivatives appearing in the time-domain permittivity model. In order to face this problem, in this paper we illustrate a FDTD scheme based on the direct solving of the time-domain Maxwell equations by using the Riemann-Liouville operator of fractional differentiation. The feasibility of the proposed method is demonstrated by simulating the transient wave propagation in general bulk and slab dispersive materials.
SAR Image Analysis, Modeling, and Techniques XIV, 2014
ABSTRACT The problems of simulation of bistatic SAR raw data and focusing are studied. A discrete... more ABSTRACT The problems of simulation of bistatic SAR raw data and focusing are studied. A discrete target simulator is described. The simulator introduces the scene topography and compute the integration time of general bistatic configurations providing a means to derived maps of the range and azimuth spatial resolutions. The problem of focusing of bistatic SAR data acquired in a translational-invariant bistatic configuration is studied by deriving the bistatic Point Target Reference spectrum and presenting an analytical solution for its stationary points.
International Journal of Optics, 2012
An optical amplifier based on a tapered fiber and an Er3+-doped chalcogenide microsphere is desig... more An optical amplifier based on a tapered fiber and an Er3+-doped chalcogenide microsphere is designed and optimized. A dedicated 3D numerical model, which exploits the coupled mode theory and the rate equations, is used. The main transitions among the erbium energy levels, the amplified spontaneous emission, and the most important secondary transitions pertaining to the ion-ion interactions have been considered. Both the pump and signal beams are efficiently injected and obtained by a suitable design of the taper angle and the fiber-microsphere gap. Moreover, a good overlapping between the optical signals and the rare-earth-doped region is also obtained. In order to evaluate the amplifier performance in reduced computational time, the doped area is partitioned in sectors. The obtained simulation results highlight that a high-efficiency midinfrared amplification can be obtained by using a quite small microsphere.