N. A. Murad

Bandwidth enhanced microstrip patch antenna using metamaterials

In this paper, a metamaterial antenna based on Split Ring Resonator (SRR) and a Thin Wire (TW) is proposed and studied. The proposed antenna consists of six unit cells and a thin wire of Left Handed Materials (LHM) arranged in 2×3 printed on same side of substrate. The TW stub of the unit cell is used to connect the LHMs to the radiating edge of a microstrip patch antenna. The constitutive parameter of the LHM is retrieve to reveal the left handed region. By using these techniques, the bandwidth of the metamaterial antenna is twice that of the ordinary patch antenna at the same operating frequency.

Dual band polarization insensitive metamaterial absorber in X-band

This paper presents the design of dual band polarization insensitive metamaterial absorber at 9 GHz and 10 GHz. The unit cell of the metamaterial consists of four circular rings copper with copper lines printed on 0.8 mm thick FR4 substrate with dielectric constant of 4.6 and loss tangent of 0.019. The simulated result shows that the dual band metamaterial absorber achieves 97.00% and 97.77% for normal incident electromagnetic waves at 9 GHz and 10 GHz respectively. The corresponding full width half maximum (FWHM) are 3.59% and 3.31%. The simulation result verified that the absorber well performance at any polarization of incident electromagnetic waves.

Reconfigurable band notch UWB antenna using EBG structure

A reconfigurable band notch UWB antenna using EBG structure is proposed. Two EBG structures is positioned alongside the feed line of the UWB antenna. The EBG structures produce two band notched at 3.97 GHz and 5.51 GHz which covers C-band satellite communication system and WLAN. The proposed antenna is suitable for UWB systems that require reconfigurable band reject function.

Design and analysis of metamaterial antenna using Triangular resonator

In this paper, a metamaterial antenna consisting of Triangular resonator (TR) and a thin wire (TW) is proposed. The antenna is excited through a single unit cell left Handed Materials (LHM) which act as the main radiating element via coplanar waveguide (CPW) transmission line. The Left Handedness of the unit cell is investigated and verified. The simulated return loss shows that a bandwidth of 58% is achieved over a frequency band of 6.42-11.23 GHz at a return loss of -10dB. The maximum gain of 4.45 is obtained at a frequency of 10.32GHz. Simulated and measured return loss shows an agreement while the radiation pattern is Omnidirectional.

Wideband metamaterial antenna employing SRR loading for WiMAX and WLAN operations

A wideband metamaterial antenna employing SRR loading is presented. Two designs were simulated, fabricated and measured. The bandwidth enhancement is achieved by loading SRR resonator onto a conventional monopole antenna. The SRR excited a lower resonance frequency mode which matches with the resonance frequency of the monopole antenna thereby extending the overall impedance bandwidth from 26% to 91%. The antenna has a compact size of 30 × 26 mm2. The peak realized gain and efficiency of 3.2 dB and 76% are obtained respectively. The antenna has potential applications for WLAN and WiMAX operations.

Dual-directional polarization insensitive multiband metamaterial absorber

This paper presents the design, simulation, fabrication, and measurement of dual-directional polarization insensitive multiband metamaterial absorber (MMAbs). The MMAbs is designed at three resonating frequency in X-band. The structure of MMAbs consists of two-layers 0.8 mm-thick FR4 substrate with three concentric copper rings-shaped structures at different radius printed on the top and bottom surface of the combined substrates. A full copper layer is placed between two FR4 substrates to reduce transmittance. The circular ring-shaped is very symmetry in nature consequently, the designed MMAbs insensitive to all polarization angles of incident electromagnetic (EM) waves for normal angle of incident. From simulation, three absorption peaks are obtained at 8, 10, and 12 GHz with absorbance of 97.27%, 83.55%, and 78.49% respectively for normal incident angle of EM waves. The corresponding full width half maximum (FWHM) bandwidths are 5.39% (7.77 - 8.20 GHz), 3.32% (9.78 - 10.11 GHz), and 2.57% (11.91 - 12.22 GHz). The structure is capable to operate at wide variation angle of incident wave. The operating angle which the MMAbs can absorb at least 50% of incident EM wave are 67° for both TE and TM polarizations. The simulation results are verified through experimental result. Mutual agreement is achieved between simulation and experimental results.

Fully textile slot linear array antenna with curvature and crumple analysis

This paper presented the investigation of wearable textile slot linear array (TSLA) antenna under flat, curvature and crumple conditions in free space designed for body worn communication application. The antenna substrate is made of 0.78 mm denim fabric with conducting monopole and ground plane is made of 0.17 mm shieldit fabric. The antenna is designed at resonant frequency of 2.45 GHz Industrial Scientific Medical (ISM) band. Simulated results show that the antenna curve and crumple significantly detuned the antenna resonance frequency and altered the antenna radiation pattern while decreased realized gain value.

Double layer circular ring metamaterial absorber for dual-directional application at 10 GHz

This report presents a double layer circular ring metamaterial absorber working at 10 GHz for dual-directional application. The structure is designed using lossy FR4 substrate with thin copper layers. The circular ring shape, which is copper metal, is printed on both side of the metamaterial structure. A copper layer is placed between two layers of FR4 substrate. From the simulation, the double layer circular ring metamaterial absorber proved to work at wide incident angle as large as 700, which maintain high absorbance, which is more than 88% for both TE and TM polarization incident waves. This kind of absorbance is also insensitive to any polarization state due to their shape of structure.

Correction of failure in linear antenna arrays with greedy sparseness constrained optimization technique

This paper proposes the correction of faulty sensors using a synthesis of the greedy sparse constrained optimization GSCO) technique. The failure of sensors can damage the radiation power pattern in terms of sidelobes and nulls. The synthesis problem can recover the wanted power pattern with reduced number of sensors into the background of greedy algorithm and solved with orthogonal matching pursuit (OMP) technique. Numerical simulation examples of linear arrays are offered to demonstrate the effectiveness of getting the wanted power pattern with a reduced number of antenna sensors which is compared with the available techniques in terms of sidelobes level and number of nulls.

Frequency reconfigurable epsilon negative metamaterial antenna based on coupled electric field resonator

This paper proposes metamaterial (MTM) antenna based on electric field coupled resonator (ELC) for frequency reconfigurable antenna. It is composed of CPW fed straight line monopole and ELC resonator with the size of 11mm × 14 mm. By inserting two PIN diodes between the gaps at both side of the ELC resonator, it is possible to switch ON or OFF the unit cell. The antenna has been simulated using CST Microwave Studio software tool. The simulation result shows that the proposed antenna is capable of reconfiguring up to four modes for five different frequencies which are 2.0 GHz, 2.10 GHz, 2.14 GHz, 2.54 GHz and 2.92 GHz.