O. El Mrabet

Polypropylene-substrate-based SRR- and CSRR-metasurfaces for submillimeter waves

In this paper it is presented the fabrication of low loss millimeter wave metamaterials based on patterning on polypropylene substrates by conventional contact photolitography. We study numerically and experimentally the transmission and reflection properties of two dimensional arrays of split ring resonators (SRRs), or metasurfaces, and their complementary structure (CSRRs) for co- and cross-polarization excitations up to submillimeter frequencies under normal incidence conditions. The obtained results suggest the possibility of scaling them at terahertz frequencies based on this substrate where other lossy substrates degrade the resonators quality. Left-handed metamaterials derived from these SRRs and CSRRs metasurfaces could be feasible.

Electroinductive waves role in left-handed stacked complementary split rings resonators

In this letter it is presented a Left-Handed Metamaterial design route based upon stacked arrays of screens made of complementary split rings resonators under normal incidence in the microwave regime. Computation of the dispersion diagram highlights the possibility to obtain backward waves provided the longitudinal lattice is small enough. The experimental results are in good agreement with the computed ones. The physics underlying the Left-Handed behavior is found to rely on electroinductive waves, playing the mutual capacitive coupling the major role to explain the phenomenon. Our route to Left-Handed metamaterial introduced in this paper based on stacking CSRRs screens can be scaled to millimeter and terahertz for future applications.

Stacked complementary metasurfaces for ultraslow microwave metamaterials

We have experimentally realized at microwaves a dual-band ultraslow regime by constructing a metamaterial based upon the alternative stack of conventional- and complementary-split-ring-resonators-surfaces. The group delay reaches values larger than two orders of magnitude than those obtained when the electromagnetic wave propagates the same thickness in free-space. The ultraslow waves have been initially predicted by a numerical eigenmode analysis and finite-integration frequency domain simulations. Such ultraslow modes can be integrated into free-space technology for spatial delay lines, and traveling wave amplifier as well as sensors due to the enhanced interaction between different beams or radiation and matter.

Global Modeling of Microwave Three Terminal Active Devices Using the FDTD Method

Abstract : This paper presents a new approach for the global electromagnetic analysis of the three-Terminal active linear and nonlinear microwave circuits using the Finite-Difference Time Domain (FDTD) Method. Here, we have updated the both electric field components on the three - terminal active device by correlating the voltage and current with its impedance. This approach is applied to the analysis of a linear amplifier which includes a three-terminal active MESFET device. Simulations results are in good agreement with those of the commercial tool.

Comments on "Rigorous modeling of packaged Schottky diodes by the nonlinear lumped network (NL /sup 2/N)-FDTD approach" [with reply]

For original paper see G. Emili et al., ibid., vol.48, no.12, p.2277-82 (2000). The commenters point out several errors in equations and parameters presented in the original paper, that should be corrected to allow an accurate implementation of the model proposed for packaged Schottky diodes using a nonlinear lumped-network finite-difference time-domain (FDTD) approach. In reply, the original authors accept that there are three errors in their work, but stress that the results presented are not affected at all by the errors, which are simply relational.

A Compact modified S-Shaped RFID tag antenna for metallic applications

In this paper, A Compact modified S-Shaped RFID Tag antenna for metallic applications is presented to handle the US Band. To miniaturize the antenna to a size of 49×21×1.58 mm3 and to provide a good conjugate matching between the S-shaped antenna and the ship, the technique of adding asymmetrical triangular stubs on both side of the tag chip which are electrically connected through vias to the ground plane were applied. The simulated results show that this antenna has good performance when attached onto metallic objects.

A dual-band compact antenna with SRR for wireless communication systems

In this work, a novel design of compact dual-band antenna based on the use of split ring resonator (SRR) is presented. The first resonant frequency can be attributed to the excitation of the second microstrip line which acts a monopole antenna; however the second frequency resonance is originated from the excitation of the SRR resonator embedded on the top layer. Excitation of the SRR element is performed by adequately position the microstrip line with respect to the confinement plane of the split ring resonator. The simulated results are analyzed and compared with measured data.

A new modified S-shaped compact antenna for RFID-UHF tag applications

In this paper, a new modified S-shaped antenna for RFID -UHF tag application is presented. To provide a good conjugate matching between the S-shaped tag antenna and the ship, the technique of adding asymmetrical triangular stubs on both side of the tag chip was applied. The proposed tag antenna operating in the 915MHz RFID band proposed here has dimensions of only 51×43 mm2 and the operating bandwidth is from 909 to 920 MHz (to cover US Band) under -10dB reflection coefficient condition. Furthermore, the measured read range was found to be 0.56 m at 915 MHz. This small value makes the proposed antenna suitable for many RFID-UHF applications, especially those that may involve short reading distance.

Exponentially tapered antipodal Vivaldi antenna for breast cancer detection

In this paper a new UWB antipodal Vivaldi antenna for breast cancer detection is presented. It is found that by inserting exponential slots into both patches of the antipodal Vivaldi antenna a good matching can be achieved , specially for the lower bandwidth limit , without degradation of the other performances of the proposed antenna. The characteristics of this antenna have been studied numerically using a commercial simulator CST microwave studio.

Wave propagation properties in stacked SRR/CSRR metasurfaces at microwave frequencies

In this paper, we study wave propagation in stacked SRR/CSRR metasurfaces at microwave frequencies. Computation of the dispersion diagram of both metasurfaces highlights the possibility to obtain forward and backward waves, respectively. The backward waves can be achieved only at the quasi-static resonance in case of stacked CSRRs metasurfaces and provided the longitudinal lattice is small enough. The experimental results for both structures show a good agreement with the computed ones. The physics underlying the left-handed behavior is found to rely on electroinductive waves, playing the interplate capacitive coupling the major role to explain the phenomenon.