Hocine Kimouche

An optimized shaped antenna for multiband applications using Genetic Algorithm

In this paper, a novel shaped microstrip patch antenna fed by microstrip lines is proposed. This antenna optimally designed, is achieved by applying Genetic Algorithm (GA) to find the optimum parameters for shaped configuration. The objective function constitutes a multi-objective optimization problem. The simulation and measured results show good multiband antenna suitable for applications operating at 2.4/3.6/5.5GHz (WLAN communications systems). Also, good antenna performances such as radiation patterns and antenna gains over the operating bands have been observed.

Multiband microstrip antenna array for modern communication systems

This paper presents the design and development of a microstrip G-shape multiband antenna operating at 3.7 GHz, 5.2 GHz and 5.8 GHz. Moreover, in order to increase its gain, identical dual-element patch multiband antenna is also proposed. The array elements are fed by only one feed network, which improves the impedance bandwidth of the two element G-shape microstrip antenna. The choice of the radiating element shape depends on different factors such as: the radiated power, the multiband operation, the polarization type, the gain and the bandwidth. The array elements showed a peak gain of 4 dB at 3.7 GHz, 1 dB at 5.2 GHz and 5.2 dB at 5.8 GHz. The overall patch multiband array antenna has a compact dimension of 7.5×52.5 mm2. The comparison between the simulated and measured results showed a very good understanding, which implies the practical suitability of the proposed multiband antenna array design.

Design and Characterization of Microstrip UWB Antennas

Ultra−WideBand (UWB) technology was approved by the Federal Communications Commission (FCC) in February 2002 (FCC, 2002). According to the FCC regulations, the frequency band from 3.1 to 10.6 GHz can be used for short−range and high speed wireless communications systems. This recent allocation of a very wide spectrum of frequencies for the devices uses, with effective isotropic radiated power (EIRP) less than 41dBm/MHz has presented numerous exciting opportunities and challenges for antenna designers. UWB antennas should be effective in transmitting, compact, non dispersive, and have a good wide impedance bandwidth properties, these features are desirable for both indoor and outdoor hand−held UWB applications. In practical UWB applications, microstrip antennas that can be directly printed onto printed circuit boards (PCBs) are the most promising candidates. Such a PCB antenna has a low profile, a low manufacturing cost and can easily be integrated with other parts of monolithic microwave integrate circuit (MMIC) for a transceiver or any other UWB system. To satisfy such requirements, various types of planar antennas have been developed for UWB communications over the last few years. Also, several bandwidth enhancement techniques have been reported, to improve the impedance bandwidth of these antennas. Microstrip UWB antennas are usually constructed by etching a radiator onto the dielectric substrate of a piece of the PCB and a partial ground plane onto the opposite side if the antenna is fed by microstrip transmission line or on the same side in the case of coplanar waveguide (CPW) feeding. In the literature, many different microstrip UWB antennas with circular, elliptical, triangular, rectangular, hexagonal, and so on patches are currently being considered for UWB applications. This chapter presents an overview of UWB antennas design an characterization, some novel designs were investigated and presented. The first class of studied UWB antennas is microstrip monopole antennas including the microstrip/CPW−fed modified − elliptical monopole antennas. The second class is for UWB slot antennas, where a novel stepped inverted cone slot antenna with different stub shapes is proposed for UWB applications. In the third class a notched band UWB antenna is presented; the proposed UWB have been developed to notch−band UWB antenna by inserting a U−shape slot into patch. The advantage of this approach is that the stop−band filter (slot) can directly integrated in antenna structure. The study includes detailed parametric analysis of the antennas performances with relation to the desirable properties for UWB antennas. 15

Investigation of monostatic RCS measurement for simple and complex shapes at 9.4 GHz

In this paper Radar Cross Section (RCS) of simple and complex objects like sphere, cylinder, flat plate and Z-shaped plate is computed and measured with respect to the parameters like frequency and aspect angle. RCS diagrams of these objects are obtained with a Lab-Volt radar training system. The measurements and simulations were carried out at the radar frequency of 9.4 GHz. It shows that there is an acceptable agreement between the measured results and the simulated ones for the operating frequency.

Features influence on targets classification performance using the high range resolution profiles (HRR profiles)

In this paper, we propose the aircrafts supervised classification using the high range resolution profiles (HRR Profiles), extracted from ISAR images. The principal components are extracted from pre-processed synthetic radar data before the 1 nearest neighbour- Inn classification . The classification performances are presented in terms of the correct classification probability (Pec). (4 pages)