Hatem Rmili

Study of an Electrochemically-Deposited 3-D Random Fractal Tree-Monopole Antenna

A 3-D fractal-tree monopole antenna was realized using electrochemical deposition technique. Experimental results on the return loss over the band 1-20 GHz and radiation patterns at all resonating frequencies were presented. The multiband electromagnetic behavior of the antenna was studied and compared to a previously reported 2-D fractal-tree antenna studied by C. Puente It is shown that the impedance bandwidth of the 3-D structure were improved compared to the reported 2-D structure with less dense band distribution. The resonating bands of the fractal structure are related to the length distribution over the fractal shape. Results for the 3-D fractal-tree antenna structure show the expected self-similar behavior

Microwave Conductivity Measurements of High Conductive Polyaniline Films

This article presents several techniques for determining the complex conductivity of highly electrically conducting polymer films at microwave frequencies. The advantages and disadvantages of these techniques are discussed. Microwave measurements were investigated using resonant cavity, reflection/transmission, and impedance surface techniques. The dc conductivity was measured using the four wires technique. Polyaniline (PANI/DEHEPSA) films of 120 μm thickness have conductivity of (5000–6000 S/m) and permittivity of 6000±1000 over X and S bands. The high values of the measured conductivity and its weak dependence on frequency at least up to 12 GHz confirm the metallic character of Pani films and their efficient use in microelectronic technology such as microwave integrated circuits (MMIC) and microwave devices.