Mohamad Mantash

Investigation of Flexible Textile Antennas and AMC Reflectors

In this paper, two different methods for fabric characterization are presented: a single frequency method and a broadband method. Felt and denim fabrics are characterized, and patch antennas are designed using these substrates to test both methods. Prototypes of the antennas on felt and denim are manufactured using conductive textile (called electrotextile) aiming to obtain fully flexible antennas. The prototypes are characterized in anechoic chamber to be compared and obtain conclusions related to the characterization methods. A new dual-band hexagonal AMC reflector combinable with antennas is also proposed to improve their performance and reduce the backward radiation to the human body. A novel broadband CPW-fed monopole antenna is designed to be combined with the AMC. The resulted prototype is characterized and compared with the performance of the CPW-fed antenna alone.

Dual-band CPW-fed G-antenna using an EBG structure

In this paper, a configuration is proposed to improve the performance of CPW antennas placed over an EBG material for dual band on body antenna applications. The aim was to improve the performance of such type of antennas by varying the position of the EBG with respect to the antenna. Simulation results show that the gain of the antenna is improved over the required frequency bands.

High Gain Array of Monopoles-Coupled Antennas for Wireless Applications

An array of monopole antennas over a ground plane that radiates a directive lobe in the end-fire direction are described in this paper. The design uses the rigorous method described by Drouet et al. 2008 in order to synthesize the radiation through the strong cumulative coupling between the monopoles. A gain higher than 20 dB was achieved in the end-fire direction over a 4.5% bandwidth. However, the antenna has been tilted in order to compensate the beam deviation caused by the edge diffraction. A prototype with 12 elements has been manufactured in order to validate the antenna principle and the whole antenna is successfully measured. The prototype was studied with the software CST-Microwave Studio and the feed network has been designed with Agilent ADS.

Characterisation of a small switchable ribbon monopole antenna operating in VHF/UHF bands

This paper describes the development of a small ribbon monopole antenna for UHF and VHF frequency maritime applications. A LC-matching circuit is used to have the antenna resonance in VHF band. In order to have a compact structure a device is used to switch between the two bands (UHF and VHF). Experimental and numerical results demonstrate that the proposed antenna exhibits a bandwidth of approximately 12.3% and 4% for UHF (420 MHz) and VHF (167 MHz) respectively. The total efficiency of the antenna was measured with two methods (reverberation chamber and Wheeler cap): it was higher than 90% in the both UHF and VHF bands. A switch device was introduced to have one antenna, and good results were obtained. Gain measurement is performed in UHF band.

Miniaturization of an artificial magnetic conductor with interdigital capacitances

This paper deals with a method to miniaturize an artificial magnetic conductor using interdigital capacitances. An artificial magnetic conductor with a resonance frequency of 2.66 GHz is designed and manufactured. The size of a unit cell is 15 χ 15 mm2 or 0.13 × 0.13 λο. The measurement result shows a resonance frequency slightly higher than the simulated one. Two circuit models are proposed to model the simulation and measured results.