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Papers by Frédérique Gadot

Research paper thumbnail of Amplification de la réfraction anormale dans un prisme-BIP

Research paper thumbnail of An adaptative beam steering antenna using a controllable EBG material for a GSM, DCS, and UMTS base station

Research paper thumbnail of A Reconfigurable Electromagnetic Bandgap Structure for a Beam Steering Base Station Antenna

Research paper thumbnail of Gadot,F. et al . Experimental demonstration of complete photonic bandgap in graphite structure. Appl. Phys. Lett 71, 1780- 1782

Applied Physics Letters

We experimentally demonstrate the existence of complete photonic band gap in graphite-type photon... more We experimentally demonstrate the existence of complete photonic band gap in graphite-type photonic crystals, thereby confirming theoretical predictions reported in previous studies. Experiments are performed at microwave frequencies from 27 to 75 GHz using hexagonal lattices of alumina rods. Transmission spectra measured for E (TM) and H (TE) polarizations and for different orientations of the two-dimensional lattice are found to

Research paper thumbnail of Matériau à main gauche fonctionnant à 2µm

Research paper thumbnail of Radome conformé contrôlable en bande X à base de matériaux à bande interdite électromagnétique commandables pour l’aéronautique

Research paper thumbnail of Conformable Radomes Based on Bi-Layered Electromagnetic Band Gap Materials

Conformable bi-layered Electromagnetic Band Gap structures composed of metallic wire strips are a... more Conformable bi-layered Electromagnetic Band Gap structures composed of metallic wire strips are applied to radomes. These structures are used either to have total transmission or reflection depending on the configuration of the wires.

Research paper thumbnail of Experimental Demonstration of the Dependency of the Negative Optical Index of a Left-Handed Material Versus the Incidence Angle

Electromagnetic Materials - Proceedings of the Symposium F, ICMAT 2003, 2003

Research paper thumbnail of Conformable and Controllable Radome in X Band using Electromagnetic Band Gap Material

2007 Loughborough Antennas and Propagation Conference, 2007

Research paper thumbnail of Band Gap Engineering in Metallic PBG Materials at Microwave Frequencies using Composite Material and Defect Lattice

Solid Mechanics and Its Applications, 2001

ABSTRACT

Research paper thumbnail of The use of controllable photonic band gap (CPBG) materials: An antenna application

In this paper, we theoretically and experimentally demonstrate the capability to realise controll... more In this paper, we theoretically and experimentally demonstrate the capability to realise controllable photonic band gap (CPBG) materials applied to the conformation of the radiation pattern of a planar antenna at 12 GHz. The CPBG materials studied are variable capacitance and conductance lattices fabricated with high frequency PIN diodes soldered along wires or metallic stripes on dielectric printed boards. Depending on the diode bias, the transmission factor of the lattice is controlled. Then, the emitted radiation of an antenna can be either transmitted or totally reflected by the material. In the transmission state, the antenna radiation is angular filtered by the CPBG material. In that case, it behaves like a controllable electromagnetic lens in the allowed frequency domain of the material.

Research paper thumbnail of <title>Theoretical and experimental analysis of plasmonic resonances in infrared metamaterials under normal to plane incidence</title>

Metamaterials III, 2008

Metamaterials have attracted much interest since their realization by Smith et al. [2]. A few res... more Metamaterials have attracted much interest since their realization by Smith et al. [2]. A few research teams all other the world are making them a reality in the infrared and optical regime. Following the theoretical study of C. Rockstuhl et al. [4], we have fabricated various metamaterial structures derived from the combination of SRR (Split Ring Resonators) and nano-continuous wires by diminishing the size of the legs of the SRR perpendicular to the gap. This geometrical transformation shown in the SEM (scanning electron microscope) pictures of figure 1 allows an experimental understanding of the origin of resonances in metamaterials under normal incidence. The fabrication was performed by e-beam lithography, gold on silicon. Simulations were performed using a Drude model of the electromagnetic permittivity of gold. Both measurement and simulation results lead to an accurate analyze of the plasmonic resonances of the metamaterial and open the way to their control in infrared metamaterials under normal to plane propagation.

Research paper thumbnail of <title>Full characterization of planar infrared metamaterials from far field diffraction pattern</title>

Research paper thumbnail of Design and simulation of an antenna-coupled TES bolometer

International Symposium on Photoelectronic Detection and Imaging 2011: Terahertz Wave Technologies and Applications, 2011

ABSTRACT We present a new design of an antenna-coupled superconducting transition-edge sensor (TE... more ABSTRACT We present a new design of an antenna-coupled superconducting transition-edge sensor (TES) bolometer. The incident radiation is coupled to a membrane-based twin-slot antenna and then transmitted through lossless microstrip lines to lossy meander-like microstrip lines in which a NbSi film is located between strip and dielectric layer. The NbSi film serves as both power absorber and temperature sensor (thermometer). With the help of the electromagnetic simulation software High Frequency Structure Simulator (HFSS), we have studied the performance of the twin-slot antenna. The simulation results for radiation pattern and return loss show promising prospects for this TES bolometer design. The power absorption in NbSi film is another important aspect which will be modeled in the future.

Research paper thumbnail of Experimental and Theoretical Characterization of the Geometry of Two-Dimensional Braided Fabrics

Textile Research Journal, 2002

Research paper thumbnail of Cylindrical radome in x band using a controllable electromagnetic band gap material

IET Seminar Digests, 2007

We present a conformable and controllable radome based on an Electromagnetic Band Gap (EBG) mater... more We present a conformable and controllable radome based on an Electromagnetic Band Gap (EBG) material in X band (center frequency 10 GHz). This structure is composed of metallic parallel wires conformed on a cylindrical structure. This cylindrical EBG structure can achieve the commutation of an antenna's transmitting signal. The radome we present in this paper is in a passive mode. The goal is to obtain an active one incorporating active devices periodically like PIN diodes or photoconductors in order to allow electrical or optical commutation of the EBG structure between two states, allowed or blocked. Different passive prototypes composed of either continuous or discontinuous wires are designed, fabricated and characterised. This paper presents the calculated and measured results of the transmission of the radome and the radiation pattern of the antenna associated with the radome.

Research paper thumbnail of Engineering of the metamaterial-based cut-band filter

Applied Physics A, 2014

Metamaterial-based cut-band filters are realized by combining either split-ring resonators (SRRs)... more Metamaterial-based cut-band filters are realized by combining either split-ring resonators (SRRs) close to a microstrip line or complementary split-ring resonators under this line. Indeed, their use reduces the size of conventional microwave filters. The study of this paper focuses on the influence of the association of different arrays of SRR especially on the bandwidth of the cut-band filter.

Research paper thumbnail of Design and characterization of a controllable left-handed material at microwave frequencies

2005 European Microwave Conference, 2005

ABSTRACT

Research paper thumbnail of Robustness of the behavior of microstrip lines loaded with disordered complementary split ring resonators

2013 Loughborough Antennas & Propagation Conference (LAPC), 2013

ABSTRACT In many papers, compact band-reject filters are realized by associating microstrip lines... more ABSTRACT In many papers, compact band-reject filters are realized by associating microstrip lines with complementary split ring resonators (CSRR). These studies assume that the periodicity of CSRR is perfect. However, a margin of error, related to the precision of manufacturing techniques, appears when operating these filters. In this paper, the robustness of the behavior of these filters is studied according to the degree of disturbance of the periodicity.

Research paper thumbnail of Conception of a 90-GHz metamaterial-based coupler for astrophysical applications

Applied Physics A, 2014

ABSTRACT Designed for astrophysical applications, this coupler must be as small as possible to be... more ABSTRACT Designed for astrophysical applications, this coupler must be as small as possible to be integrated in a low temperature superconducting detection chain. By using metamaterials, dimensions can be reduced and performances enhanced compared with a conventional coupler. The novelty of the work presented in this paper is a coupler that operates at millimeter waves (W band) and cryogenic temperatures (4 K) for astrophysics applications and more precisely for the detection of the cosmological microwave background radiation.

Research paper thumbnail of Amplification de la réfraction anormale dans un prisme-BIP

Research paper thumbnail of An adaptative beam steering antenna using a controllable EBG material for a GSM, DCS, and UMTS base station

Research paper thumbnail of A Reconfigurable Electromagnetic Bandgap Structure for a Beam Steering Base Station Antenna

Research paper thumbnail of Gadot,F. et al . Experimental demonstration of complete photonic bandgap in graphite structure. Appl. Phys. Lett 71, 1780- 1782

Applied Physics Letters

We experimentally demonstrate the existence of complete photonic band gap in graphite-type photon... more We experimentally demonstrate the existence of complete photonic band gap in graphite-type photonic crystals, thereby confirming theoretical predictions reported in previous studies. Experiments are performed at microwave frequencies from 27 to 75 GHz using hexagonal lattices of alumina rods. Transmission spectra measured for E (TM) and H (TE) polarizations and for different orientations of the two-dimensional lattice are found to

Research paper thumbnail of Matériau à main gauche fonctionnant à 2µm

Research paper thumbnail of Radome conformé contrôlable en bande X à base de matériaux à bande interdite électromagnétique commandables pour l’aéronautique

Research paper thumbnail of Conformable Radomes Based on Bi-Layered Electromagnetic Band Gap Materials

Conformable bi-layered Electromagnetic Band Gap structures composed of metallic wire strips are a... more Conformable bi-layered Electromagnetic Band Gap structures composed of metallic wire strips are applied to radomes. These structures are used either to have total transmission or reflection depending on the configuration of the wires.

Research paper thumbnail of Experimental Demonstration of the Dependency of the Negative Optical Index of a Left-Handed Material Versus the Incidence Angle

Electromagnetic Materials - Proceedings of the Symposium F, ICMAT 2003, 2003

Research paper thumbnail of Conformable and Controllable Radome in X Band using Electromagnetic Band Gap Material

2007 Loughborough Antennas and Propagation Conference, 2007

Research paper thumbnail of Band Gap Engineering in Metallic PBG Materials at Microwave Frequencies using Composite Material and Defect Lattice

Solid Mechanics and Its Applications, 2001

ABSTRACT

Research paper thumbnail of The use of controllable photonic band gap (CPBG) materials: An antenna application

In this paper, we theoretically and experimentally demonstrate the capability to realise controll... more In this paper, we theoretically and experimentally demonstrate the capability to realise controllable photonic band gap (CPBG) materials applied to the conformation of the radiation pattern of a planar antenna at 12 GHz. The CPBG materials studied are variable capacitance and conductance lattices fabricated with high frequency PIN diodes soldered along wires or metallic stripes on dielectric printed boards. Depending on the diode bias, the transmission factor of the lattice is controlled. Then, the emitted radiation of an antenna can be either transmitted or totally reflected by the material. In the transmission state, the antenna radiation is angular filtered by the CPBG material. In that case, it behaves like a controllable electromagnetic lens in the allowed frequency domain of the material.

Research paper thumbnail of <title>Theoretical and experimental analysis of plasmonic resonances in infrared metamaterials under normal to plane incidence</title>

Metamaterials III, 2008

Metamaterials have attracted much interest since their realization by Smith et al. [2]. A few res... more Metamaterials have attracted much interest since their realization by Smith et al. [2]. A few research teams all other the world are making them a reality in the infrared and optical regime. Following the theoretical study of C. Rockstuhl et al. [4], we have fabricated various metamaterial structures derived from the combination of SRR (Split Ring Resonators) and nano-continuous wires by diminishing the size of the legs of the SRR perpendicular to the gap. This geometrical transformation shown in the SEM (scanning electron microscope) pictures of figure 1 allows an experimental understanding of the origin of resonances in metamaterials under normal incidence. The fabrication was performed by e-beam lithography, gold on silicon. Simulations were performed using a Drude model of the electromagnetic permittivity of gold. Both measurement and simulation results lead to an accurate analyze of the plasmonic resonances of the metamaterial and open the way to their control in infrared metamaterials under normal to plane propagation.

Research paper thumbnail of <title>Full characterization of planar infrared metamaterials from far field diffraction pattern</title>

Research paper thumbnail of Design and simulation of an antenna-coupled TES bolometer

International Symposium on Photoelectronic Detection and Imaging 2011: Terahertz Wave Technologies and Applications, 2011

ABSTRACT We present a new design of an antenna-coupled superconducting transition-edge sensor (TE... more ABSTRACT We present a new design of an antenna-coupled superconducting transition-edge sensor (TES) bolometer. The incident radiation is coupled to a membrane-based twin-slot antenna and then transmitted through lossless microstrip lines to lossy meander-like microstrip lines in which a NbSi film is located between strip and dielectric layer. The NbSi film serves as both power absorber and temperature sensor (thermometer). With the help of the electromagnetic simulation software High Frequency Structure Simulator (HFSS), we have studied the performance of the twin-slot antenna. The simulation results for radiation pattern and return loss show promising prospects for this TES bolometer design. The power absorption in NbSi film is another important aspect which will be modeled in the future.

Research paper thumbnail of Experimental and Theoretical Characterization of the Geometry of Two-Dimensional Braided Fabrics

Textile Research Journal, 2002

Research paper thumbnail of Cylindrical radome in x band using a controllable electromagnetic band gap material

IET Seminar Digests, 2007

We present a conformable and controllable radome based on an Electromagnetic Band Gap (EBG) mater... more We present a conformable and controllable radome based on an Electromagnetic Band Gap (EBG) material in X band (center frequency 10 GHz). This structure is composed of metallic parallel wires conformed on a cylindrical structure. This cylindrical EBG structure can achieve the commutation of an antenna's transmitting signal. The radome we present in this paper is in a passive mode. The goal is to obtain an active one incorporating active devices periodically like PIN diodes or photoconductors in order to allow electrical or optical commutation of the EBG structure between two states, allowed or blocked. Different passive prototypes composed of either continuous or discontinuous wires are designed, fabricated and characterised. This paper presents the calculated and measured results of the transmission of the radome and the radiation pattern of the antenna associated with the radome.

Research paper thumbnail of Engineering of the metamaterial-based cut-band filter

Applied Physics A, 2014

Metamaterial-based cut-band filters are realized by combining either split-ring resonators (SRRs)... more Metamaterial-based cut-band filters are realized by combining either split-ring resonators (SRRs) close to a microstrip line or complementary split-ring resonators under this line. Indeed, their use reduces the size of conventional microwave filters. The study of this paper focuses on the influence of the association of different arrays of SRR especially on the bandwidth of the cut-band filter.

Research paper thumbnail of Design and characterization of a controllable left-handed material at microwave frequencies

2005 European Microwave Conference, 2005

ABSTRACT

Research paper thumbnail of Robustness of the behavior of microstrip lines loaded with disordered complementary split ring resonators

2013 Loughborough Antennas & Propagation Conference (LAPC), 2013

ABSTRACT In many papers, compact band-reject filters are realized by associating microstrip lines... more ABSTRACT In many papers, compact band-reject filters are realized by associating microstrip lines with complementary split ring resonators (CSRR). These studies assume that the periodicity of CSRR is perfect. However, a margin of error, related to the precision of manufacturing techniques, appears when operating these filters. In this paper, the robustness of the behavior of these filters is studied according to the degree of disturbance of the periodicity.

Research paper thumbnail of Conception of a 90-GHz metamaterial-based coupler for astrophysical applications

Applied Physics A, 2014

ABSTRACT Designed for astrophysical applications, this coupler must be as small as possible to be... more ABSTRACT Designed for astrophysical applications, this coupler must be as small as possible to be integrated in a low temperature superconducting detection chain. By using metamaterials, dimensions can be reduced and performances enhanced compared with a conventional coupler. The novelty of the work presented in this paper is a coupler that operates at millimeter waves (W band) and cryogenic temperatures (4 K) for astrophysics applications and more precisely for the detection of the cosmological microwave background radiation.