Habib Zangar

Efficient, metamaterial-inspired loop-monopole antenna with shaped radiation pattern

A new family of metamaterial-inspired monopole antennas is reported. Split-ring resonator (SRR) is introduced into the near field region of a monopole antenna. Four configurations are proposed by changing the position of the slot of the SRR. In each case, we obtain a new behavior and a new resonance frequency, in addition to that of the monopole. The results are presented for the return loss, efficiency, surface current and radiation pattern. Four prototypes are fabricated and measured. Good agreement between numerical and experimental results is demonstrated.

Design of a planar reconfigurable band-rejected UWB antenna for multi-standard wireless communication systems

A planar elliptic ultra wideband (UWB) antenna with reconfigurable band-stop performances was successfully designed and manufactured for multi-standard wireless communication systems. The proposed antenna consists of a very high selective band-rejected UWB micro-strip fed monopole operating from 0.65 to over 6 GHz. Frequency agility was produced by loading a varactor diode on the open loop resonator printed on the front side of the substrate close to the micro-strip feeding line. The frequency reconfigurable monopole achieves extremely sharp and narrow band rejection of the WiMAX (3.5 GHz) band when the varactor diode is disconnected. A prototype was realized, the measured reached tuning range of the fabricated reconfigurable antenna is from 3.869 to 4.344GHz. Measured results are presented and discussed.

Design of planar mono-band rejected UWB CPW-Fed antennas for wireless communications

In this paper, two compact modified square-shaped ultra wideband (UWB) monopole antennas with band rejected capability using open slots and parasitic loop are presented. The CPW-Fed printed monopole structures are designed for UWB wireless communications with rejection of bands 5.725–5.830 GHz and 7.25–7.30 GHz, allocated for military operations. The design details and related results are presented and discussed.

Design of an FP/EBG antenna with metamaterial PRS

FP/EBG antennas have received intensive attention and large investigations during the last decade. The development of such structure opened the field for real industrial applications in the microwave domain, especially for the antenna design. In this paper we present an FP/EBG antenna operating around 2GHz. The structure consists of a Fabry-Perot Cavity composed of a ground plane, an air cavity and a Partially Reflecting Surface (PRS) made of SRR cells (Slot Ring Resonator). The simulation results show a directivity enhancement of about 4 dB. This structure can be used as directive antenna in communication systems.

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.