with a resonance around 9.2 GHz, simulation and test prove that could absorb electromagnetic wave, results of HFSS simulation show that have reduced RCS markedly with the largest scope of Ϫ6 dBm at a frequency around 9.0 GHz. Controllable metamaterial electromagnetic structure with microstruture will may be applied into stealth design and stealth technology for aircrafts, warships, and sateliites in the future.

An efficient electronic beam steering technique in time modulated linear array (TMLA) is proposed, where the first positive and negative sidebands are utilised to implement the electronic steering process. In this technique, new periodic time sequences are used, in which a positive‐ON, negative‐ON, and OFF durations are utilised to obtain high sufficient steering in TMLA. Furthermore, it is shown that by using these time sequences, the non‐steerable array pattern at the fundamental frequency and also the even sidebands can be eliminated and nulled to zero. In addition, the radiation power and the directivity of this proposed steered‐TMLA are formulated in their closed form. The genetic algorithm is implemented to optimise the steered‐TMLA by suppressing the remaining odd sidebands and increasing the power radiation at the first positive and negative sidebands.

The polarization mode dispersion (PMD) is a difficult phenomenon to compensate in the optical fiber. Its reduction can be achieved by the spinning process that provokes the rotation of the birefringence axes of the fiber inciting a coupling of its modes that is controlled at the time of its manufacture. In this work, the Jones Matrix Eigen-Analysis method (JME) is used to characterize the spun fibers to evaluate their PMD and to prove that it is distinctly lower than the standards fibers PMD. Furthermore, the differential group delays (DGD) of spun fibers is determined using the photon counting optical time-domain reflectometry (C-OTDR) method. The obtained results are compared with those found in the JME method. It is noted that the two methods yield practically identical values. The determination of the beat length and the spin period of spun fibers are carried out using the polarization-sensitive optical frequency-domain reflectometer (POFDR).

This article investigates a quasitriangular of defected ground structure (DGS) for low‐pass filters (LPFs) application. An equivalent RLC circuit model is presented and its corresponding parameters are as well extracted using the parametric relationships. The LPFs using the proposed DGS pattern combined with open stubs are designed and fabricated. The proposed LPF presents the advantages of small size, low insertion loss and ultrawide stopband with 20 dB attenuation from 4 GHz to >20 GHz. The simulated results obtained by equivalent circuit model and full‐wave electromagnet show good agreement with the measured ones. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:122–127, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27260

No abstract

In this article, a novel frequency switchable method for Ultra‐Wide‐Band (UWB) microstrip antenna with dual notches is presented and discussed. This method is based on hexagonal‐shaped Split Ring Resonator (SRR) metamaterial cells located close to the 50‐Ω feed line and ideal switches inserted at the inner and the outer SRR of each cell. The incorporation of these ideal switches helps in changing the location of the opening of the inner ring (inner ring fictive rotation) and in activating or deactivating the filtering introduced by the metamaterial cells. The resulting radiating structure has an impedance bandwidth extending from 2.8 GHz to more than 11GHz accompanied with dual notched bands characteristic. It offers several cases by opening or closing the ideal switches. The obtained simulation results agree well with measurements carried out on the fabricated prototypes.

This paper presents a compact monopole antenna for radio frequency identification (RFID) systems. The proposed antenna is a dual band structure that can operate in the frequency ranges [0.797–1.004 GHz] and [2.234–2.934 GHz]. Consequently, the antenna covers widely the two UHF bands dedicated for RFID applications which are [0.860–0.960 GHz] and [2.380–2.520 GHz]. Moreover, the antenna is compact and its wide band nature makes it suitable for several applications other than RFID (GSM, UMTS, Wi‐Fi, Bluetooth, etc.). The proposed antenna has been fabricated and its reflection coefficient measured where a good agreement is observed with the simulated results.

The presented work in this article concerns a new ultra-wideband antenna design with an octagonal configuration and reduced dimensions. Different prototypes have been simulated and implemented in the form of monopoles. These prototypes have shown an admissible agreement between simulations and measurements and ultra-wide bands running from 3.1 to 14 GHz for wireless applications. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:692–697, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.2666