24 research outputs found
Design of a novel Comact ans Superdirective Two and Three Elements Antenna Array
International audienc
Femtosecond and nanosecond pulsed laser deposition of silicon and germanium
150 fs Ti:Sapphire laser pulsed laser deposition of Si and Ge were compared to a nanosecond KrF laser (25 ns). The ablation thresholds for for ns lasers were about 2.5 Jcm−2 for Si and 2.1 Jcm−2 for Ge. The values were about 5-10 times lower when fs laser were used. The power densities were 108-109 Wcm−2 for ns but 1012 Wcm−2 for fs. By using an ion probe, the ions emission at different fluence were measured where the emitting ions achieving the velocity in the range of 7-40 kms−1 and kinetic energy in the range of 30-200 eV for ns laser. The ion produced by fs laser was measured to be highly energetic, 90-200 kms−1, 2-10 KeV. Two ion peaks were detected above specific laser fluence for both ns and fs laser ablation. Under fs laser ablation, the films were dominated by nano-sized crystalline particles, drastically different from nanosecond pulsed laser deposition where amorphous films were obtained. The ions characteristics and effects of pulse length on the properties of the deposited films were discussed
A Reconfigurable Radiation Pattern Metamaterial-Inspired Circular Array Antenna
International audienc
Design of a Multi-Band Metamaterial-Inspired Dipole Antenna with Director Element
International audienc
Rectangular Bi-Loop Single-Feed Antenna with Polarization Agility Property for GPS and Iridium Applications
International audienc
Design of Reconfigurable Radiation Pattern Ring-Dipole Antenna for Wireless Communication
International audienc
Design of a printed Elliptic Reconfigurable Dual Band-rejected UWB Micro-strip Fed Antenna
International audienc
Design of Reconfigurable Radiation Pattern Dipole Antenna with Director and Reflector Elements for Telecommunications Systems
International audienc