M. Essaaidi

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.

A COMPACT SPLIT RING RESONATOR ANTENNA FOR WIRELESS COMMUNICATION SYSTEMS

In this paper, we report a new design of a compact antenna based on the use of split ring resonator (SRR). The designed antenna consists of two SRRs, with the same geometrical parameters, printed symmetrically on both sides of the dielectric substrate. Excitation of the SRR element is performed by adequately placing the access microstrip lines with respect to the conflnement plane of the split rings. The resonance frequency of the antenna is essentially deflned by geometrical parameters of the SRR, which makes it suitable for a broad range of applications spanning from mobile terminals to WLAN and WPAN systems. The flnal result is low proflle, and can be easily integrated with other RF front-end circuits in a PCB.

A Dual Ultra Wide Band Slotted Antenna for C and X Bands Application

In this paper, a novel compact dual-band microstrip antenna operating at two difierent bands, namely, C-band and X-band is presented and analyzed. The dual ultra wide band is realized by cutting two triangular slots on the right and on the left sides of the patch and a rectangular slot on the top side of the patch. The antenna structure is optimized and simulated using commercial software. The excitation is launched through a 50Ohms microstrip-line. According to simulation and measured results the proposed antenna can provide two separated impedance bandwidths of 500MHz centered at 7GHz and 2GHz centered at 10.7GHz and stable radiation patterns.

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 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.

Novel compact dual-and tri-band filters using stepped impedance resonators

We present in this paper a novel approach for dual-and tri-band filters design with independently controlled center frequencies and bandwidths. On the one hand, a stepped impedance resonator (SIR) is designed to operate at the center frequencies of two bands simultaneously (dual-band), on the other hand, two stepped impedance resonators are designed to operate at the center frequencies of three bands simultaneously (tri-band). To verify the proposed approach two filters are designed and analyzed by using Sonnet and HFSS simulators, the obtained results using these two simulators are in very good agreement

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.

TRANSMISSION PROPERTIES OF STACKED SRR METASURFACES IN FREE SPACE

In this paper, transmission properties of stacked split ring resonators metasurfaces in free space and under normal incidence are investigated experimentally and numerically. Emphasis is put on studying the interaction between adjacent SRRs metasurfaces. The thorough analysis of the electromagnetic flelds shows that both magnetic and electric coupling can occur between adjacents metasurfaces for vertical and horizontal polarization. In addition, we found that all propagating bands within our spectral window (up to 20GHz) support right-handed behaviour. Both simulation and experiment results in the microwave regime are in good agreement.