Ali Foudazi - Profile on Academia.edu (original) (raw)

Papers by Ali Foudazi

A Dual-Mode Substrate Integrated Waveguide Filter Using Coupling Via

The non-uniform distribution of steel fibers in fiber-reinforced cement-based mortars (FRCMs) can... more The non-uniform distribution of steel fibers in fiber-reinforced cement-based mortars (FRCMs) can lead to heterogeneous properties of hardened material with direct impact on mechanical properties. Among various nondestructive testing techniques, the active microwave thermography (AMT) has shown good potential for inspection of cement-based materials. AMT utilizes combination of microwave energy to generate controlled and localized heating and uses commercially-available infrared cameras to capture surface thermal images in real-time. Utilizing AMT, four FRCM samples made with different steel fiber volumes ranging from 0 to 3 % were investigated to evaluate the feasibility of this method for detecting and quantifying fiber distribution. Full-wave coupled electromagnetic-thermal numerical modeling was also conducted to evaluate the effect of dielectric properties, fiber depth, and fiber clumping on surface thermal profile. The results of simulations indicate that increase in fiber depth results in lower surface temperature, due to lower heating associated with induced surface current. Based on AMT measurement results, samples with higher fiber contents were shown to undergo greater increase in surface temperature, as observed for samples with 1 and 2 % fibers. However, this tendency was reversed with further fiber addition from 2 to 3 %, due to the potential of fiber clumping. Furthermore, the fiber clumping and lower level of fiber homogeneity for FRCM with 3 % fiber resulted in 55 % lower flexural toughness compared to the FRCM containing 2 % fiber. The results of fiber homogeneity measured from freshly cast prism were found to correlate well with those obtained from AMT technique determined on hardened samples.

— Microwave material characterization is an important nondestructive evaluation tool, as many phy... more — Microwave material characterization is an important nondestructive evaluation tool, as many physical and chemical properties can be related to a material's dielectric properties. These properties can be measured using a number of methods including the loaded waveguide technique. This method requires that a sample be placed in a waveguide sample holder and subsequently utilizes measured complex reflection (S 11) and transmission (S 21) properties to calculate the sample's dielectric properties. As such, it is important that the sample be prepared carefully, as the dielectric property calculation assumes a perfect (ideal) sample geometry. However, in practice, samples are oftentimes prepared by hand, resulting in a distorted sample geometry. This paper presents a simulation and measurement study on a number of potential sample preparation errors and the effect of these errors on calculated dielectric properties. Finally, a statistical analysis (including mean, standard deviation, coefficient of variation, and confidence interval) was applied to provide a method by which calculated dielectric properties (even when imperfect samples are used) can be checked to ensure that proper accuracy of the results has been achieved.

The contents of this report reflect the views of the author(s), who are responsible for the facts... more The contents of this report reflect the views of the author(s), who are responsible for the facts and the accuracy of information presented herein. This document is disseminated under the sponsorship of the Center for Infrastructure Engineering Studies (CIES), Missouri University of Science and Technology, in the interest of information exchange. CIES assumes no liability for the contents or use thereof.

Detection and characterization of corrosion on steel is important in the transportation and infra... more Detection and characterization of corrosion on steel is important in the transportation and infrastructure industries. Many nondestructive testing (NDT) methods have been applied to this inspection need. To overcome the existing limitations of traditional NDT methods, integrated NDT techniques have also been developed. To this end, the integration of microwave and thermography, referred to as active microwave thermography (AMT), is proposed as a potential NDT tool for detection and characterization of corrosion on steel bars. This method utilizes microwave energy to provide heat excitation. Subsequently, a thermal camera is used to monitor the thermal surface profile. This paper presents preliminary simulations and measurements of AMT as a potential method for corrosion detection and characterization.

Health monitoring of infrastructure is very important in the transportation and infrastructure i... more Health monitoring of infrastructure is very
important in the transportation and infrastructure industries.
Many nondestructive testing (NDT) techniques have been applied
for structural health monitoring including microwave NDT,
ultrasound, thermography, etc. Due to the complex materials
(composites, concrete, etc.) commonly used, it may be difficult to
thoroughly inspect a structure using one method alone. Thus,
hybrid NDT methods have also been developed. Recently, the
integration of microwave NDT and thermography, herein
referred to as Active Microwave Thermography (AMT), has also
been considered as a potential structural health monitoring tool.
This hybrid method uses microwave energy to heat a structure of
interest, and then the thermal surface profile is measured using a
thermal camera. This paper investigates the potential of AMT to
inspect rehabilitated cement-based structures. Preliminary
simulations and measurements provided herein indicate that
AMT has the potential to detect delaminations under carbon
fiber patches bonded to concrete.

Inspection of carbon fiber reinforced polymer (CFRP) composites is very important in the aeronau... more Inspection of carbon fiber reinforced polymer
(CFRP) composites is very important in the aeronautical and
transportation industries. Many nondestructive testing (NDT)
techniques have been applied for health monitoring including
ultrasound, thermography, etc. Although thermography has been
widely used for this purpose, it often requires powerful heat
lamps which may increase the risk of (thermal) damage to the
structure under test. Thus, hybrid NDT methods have also been
developed. Recently, the integration of microwave heating and
thermography, herein referred to as Active Microwave
Thermography (AMT), has also been considered as a potential
health monitoring tool for infrastructure. This hybrid method
uses microwave energy to heat a structure of interest, and
subsequently the thermal surface profile is measured using a
thermal camera. This paper investigates the potential of AMT for
inspection of CFRP-rehabilitated airframes. Preliminary
simulations and measurements indicate that AMT has the
potential to detect disbonds under carbon fiber patches bonded
to aluminum.

In this article, an integrated broadband planar monopole antenna with extra frequency bands is pr... more In this article, an integrated broadband planar monopole
antenna with extra frequency bands is presented. The proposed antenna
consists of a simple square shaped planar. The center part of the plate
can be removed with negligible effect on reflection coefficient. To
improve the impedance matching of the planar antenna, the lower corner
of the antenna is removed. Also, the higher cut-off frequency is
enhanced by an additional strip at the top corner of the plate. By inserting
additional strips in the path of the notched part of the plate, integrated
broadband antenna with extra bands can be attained which leads
to dual- and triple-band antenna. The additional bands cover 1.71–1.88
(DCS) and 2.4–2.48 (WLAN). Simulation and measurement results of the
proposed antenna agree well and show good performance for multiband
behavior.

IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, Jun 2012

A small-size microstrip-fed multi-band planar monopole antenna is presented. The base of the prop... more A small-size microstrip-fed multi-band planar monopole antenna is presented. The base of the proposed antenna is a diamond-shapedpatch (DSP) that covers the ultrawideband (UWB) frequency range. To create a multi-band antenna, several narrow strips, acting as resonance paths, can be integrated with the DSP antenna. It is shown that by removing the centre part of the DSP antenna, without distorting the UWB behavior, quarter-wavelength strips can be added to the notched region. This will not affect the dimension of the base antenna. The designed quad-band antenna has a substrate size of 16 22 mm and covers the frequency bands 1.3, 1.8, 2.4 and 3.1-10.6 GHz which includes GPS, GSM, WLAN and UWB. Dual-, triple-and quad-band antennas are simulated and good results are obtained. The antennas have omnidirectional and stable radiation patterns across all the relevant bands. Moreover, relatively consistent group delays across the UWB frequencies are noticed for the base, dual-and triple-band antennas, and slightly distorted for the quad-band antenna. A prototype of the quad-band antenna is fabricated and measured results are compared with simulated results. Index Terms-Monopole antenna, multi-band antenna, ultrawideband (UWB) antenna, wireless communication frequencies.

IET Microwaves, Antennas & Propagation, Nov 2012

The authors present a new optimisation method for pattern synthesis of multi-feed reflector anten... more The authors present a new optimisation method for pattern synthesis of multi-feed reflector antennas in this study. By using an invasive weed optimisation (IWO) algorithm, shaped beam antennas are designed. The results of the IWO algorithm for the synthesis of cosecant squared and contoured beam patterns are presented and compared with particle swarm optimisation algorithm results. The far-field radiation patterns of reflector antennas, fed by linear and planar array of conical horn antennas, are provided by a physical optics and the error between desired and provided radiation patterns is calculated by a root mean square method. The results show that the IWO algorithm, which provides good convergence, is stable and adaptive-to-change for different boundary conditions in pattern synthesis applications.

In this article, an integrated broadband planar monopole antenna with extra frequency bands is pr... more In this article, an integrated broadband planar monopole antenna with extra frequency bands is presented. The proposed antenna consists of a simple square shaped planar. The center part of the plate can be removed with negligible effect on reflection coefficient. To improve the impedance matching of the planar antenna, the lower corner of the antenna is removed. Also, the higher cut-off frequency is enhanced by an additional strip at the top corner of the plate. By inserting additional strips in the path of the notched part of the plate, integrated broadband antenna with extra bands can be attained which leads to dual- and triple-band antenna. The additional bands cover 1.71–1.88 (DCS) and 2.4–2.48 (WLAN). Simulation and measurement results of the proposed antenna agree well and show good performance for multiband behavior.

In this paper, a method is proposed to find the suitable antenna for a GSM urban macro cell cover... more In this paper, a method is proposed to find the suitable antenna for a GSM urban macro cell covered by a base transceiver station (BTS) mounted on high altitude platform (HAP) at the sfratosphere layer. To this end, an ideal cosine shape radiation pattern raised to the power of N is applied to select the appropriate antenna for achieving the optimum coverage. The optimum selection is based on minimizing the blind area, having less overlapped to total area ratio, and increasing the total coverage area, simultaneously. Our proposed scheme has two degrees of freedom; first, the values of N determining the directivity and half power beam width (HPBW), and second the angle a denoting to the mechanical tilt of the antenna elements. To find the optimum pair of (N, a), several simulations are done and the corresponding footprint contours are depicted. Simulation results show that utilizing three ideal cosine function antennas with N = 9 installed by a = 38 degrees of mechanical tilt with respect to the normal is optimum for a macro cell coverage in an urban area by using HAPs located at 17 km altitude.

IEEE LAPC 2011, 2011

This paper provides a dual-band printed wide slot microstrip-fed antenna. The proposed antenna co... more This paper provides a dual-band printed wide slot microstrip-fed antenna. The proposed antenna consists of a Ushaped radiating patch, a T-shaped monopole path and a Pentagonal-shaped wide slot in the ground plane. The dual-band antenna can cover both 2.4 GHz (WLAN) and 3.1-10.6 GHz (UWB) frequency ranges. The antenna size is 28 × 28 × 1 mm 3 which fabricated on a FR4 substrate. The simulation and measured results of the proposed antenna are presented and show good agreement in reflection coefficient and radiation patterns.

IEEE LAPC 2011, 2011

This paper presents a broadband printed circularly polarized monopole antenna. The base antenna c... more This paper presents a broadband printed circularly polarized monopole antenna. The base antenna consists of a falcate-shaped monopole antenna which provides 43% axial ratio bandwidth. By inserting a falcate-shaped slot in the base patch, 56% axial ratio is obtained. Moreover, inserting a slot in the base patch has no effect on the impedance bandwidth of the original structure. The proposed antenna dimension is 40 × 46 mm 2 and is fabricated on 1 mm FR4 substrate. The simulated return loss and axial ratio bandwidth of the antenna structure with and without the falcate shaped slot are presented and compared. Moreover, circular polarization radiation patterns of the proposed antenna are presented.

IEEE EuCAP 2012, 2012

In this paper, a new optimization algorithm to design shaped beam antenna is proposed. It is show... more In this paper, a new optimization algorithm to design shaped beam antenna is proposed. It is shown that by using offset parabolic reflector antenna and a linear array of horn antennas with one-wavelength spacing in focal point, Invasive Weed Optimization (IWO) algorithm can be used for amplitude and/or phase of source antennas to provide desired cosecant squared radiation patterns. To achieve a simple cosecant squared radiation pattern, amplitudes and phases of 11 source antennas (22 parameters) are optimized with no constraint by IWO and the results are compared with Particle Swarm Optimization (PSO) algorithm. Convergence diagram and radiation pattern results confirm the capability of IWO algorithm in shaped beam antenna design.

IEEE EuCAP 2012, 2012

A new method to design a cosecant squared radiation pattern in a shaped reflector antenna is prop... more A new method to design a cosecant squared radiation pattern in a shaped reflector antenna is proposed. Surface of the proposed reflector antenna is expanded by modified Jacobi polynomials. The expansion coefficients are optimized by using particle swarm optimization (PSO) algorithm to achieve desired cosecant squared radiation pattern in elevation plane and a narrow pencil beam radiation pattern in azimuth plane. The antenna is analyzed by physical optics (PO) method.

Microwave & RF, Apr 2013

This compact, circularly polarized, dual-band antenna provides sufficient bandwidth making it ide... more This compact, circularly polarized, dual-band antenna provides sufficient bandwidth making it ideal for GSM and UMTS base-station applications.

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Mar 2013

In this article, a dual-band WLAN/ultrawideband (UWB) printed wide slot microstrip-fed antenna is... more In this article, a dual-band WLAN/ultrawideband (UWB) printed wide slot microstrip-fed antenna is presented for multi-input multi-output (MIMO)/diversity applications. The proposed antenna consists of a U-shaped patch, a T-shaped monopole path, and a pentagonal wide slot in the ground plane. The antenna is designed to cover both the WLAN (2.4-2.485 GHz) and UWB (3.1-10.6 GHz) ranges, with value of S 11 below À10 dB. The antenna is constructed on a FR4 substrate with overall dimensions of 28 Â 28 Â 1 mm 3 . It is shown that the proposed dual-band antenna is suitable for diversity polarization applications. The simulation results show that the different configurations of the antenna in the MIMO/diversity have good Sparameters over the operating frequency bands. The simulation and measured results of the proposed dual-band antenna as well as that of the MIMO/diversity antenna configuration agree well. V C 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:461-465, 2013; View this article online at wileyonlinelibrary.com.

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Jul 2011

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, May 2012

filter occupies a small size of 8.7 mm by 2.4 mm. For the measurement, a 5-mm long microstrip fee... more filter occupies a small size of 8.7 mm by 2.4 mm. For the measurement, a 5-mm long microstrip feed line is added at both input and output. demonstrates the EM-simulated and experimental results of the proposed filter, where excellent agreement is obtained. The measured insertion loss is found to be less than 0.8 dB at the center frequency of the UWB passband. The measured return loss is better than 13 dB over the whole UWB passband. The filter shows the two new transmission zeros at the lower and upper edges of the desired passband, which enhanced the selectivity of the lower and the upper skirts of the UWB passband.

A Dual-Mode Substrate Integrated Waveguide Filter Using Coupling Via

The non-uniform distribution of steel fibers in fiber-reinforced cement-based mortars (FRCMs) can... more The non-uniform distribution of steel fibers in fiber-reinforced cement-based mortars (FRCMs) can lead to heterogeneous properties of hardened material with direct impact on mechanical properties. Among various nondestructive testing techniques, the active microwave thermography (AMT) has shown good potential for inspection of cement-based materials. AMT utilizes combination of microwave energy to generate controlled and localized heating and uses commercially-available infrared cameras to capture surface thermal images in real-time. Utilizing AMT, four FRCM samples made with different steel fiber volumes ranging from 0 to 3 % were investigated to evaluate the feasibility of this method for detecting and quantifying fiber distribution. Full-wave coupled electromagnetic-thermal numerical modeling was also conducted to evaluate the effect of dielectric properties, fiber depth, and fiber clumping on surface thermal profile. The results of simulations indicate that increase in fiber depth results in lower surface temperature, due to lower heating associated with induced surface current. Based on AMT measurement results, samples with higher fiber contents were shown to undergo greater increase in surface temperature, as observed for samples with 1 and 2 % fibers. However, this tendency was reversed with further fiber addition from 2 to 3 %, due to the potential of fiber clumping. Furthermore, the fiber clumping and lower level of fiber homogeneity for FRCM with 3 % fiber resulted in 55 % lower flexural toughness compared to the FRCM containing 2 % fiber. The results of fiber homogeneity measured from freshly cast prism were found to correlate well with those obtained from AMT technique determined on hardened samples.

— Microwave material characterization is an important nondestructive evaluation tool, as many phy... more — Microwave material characterization is an important nondestructive evaluation tool, as many physical and chemical properties can be related to a material's dielectric properties. These properties can be measured using a number of methods including the loaded waveguide technique. This method requires that a sample be placed in a waveguide sample holder and subsequently utilizes measured complex reflection (S 11) and transmission (S 21) properties to calculate the sample's dielectric properties. As such, it is important that the sample be prepared carefully, as the dielectric property calculation assumes a perfect (ideal) sample geometry. However, in practice, samples are oftentimes prepared by hand, resulting in a distorted sample geometry. This paper presents a simulation and measurement study on a number of potential sample preparation errors and the effect of these errors on calculated dielectric properties. Finally, a statistical analysis (including mean, standard deviation, coefficient of variation, and confidence interval) was applied to provide a method by which calculated dielectric properties (even when imperfect samples are used) can be checked to ensure that proper accuracy of the results has been achieved.

The contents of this report reflect the views of the author(s), who are responsible for the facts... more The contents of this report reflect the views of the author(s), who are responsible for the facts and the accuracy of information presented herein. This document is disseminated under the sponsorship of the Center for Infrastructure Engineering Studies (CIES), Missouri University of Science and Technology, in the interest of information exchange. CIES assumes no liability for the contents or use thereof.

Detection and characterization of corrosion on steel is important in the transportation and infra... more Detection and characterization of corrosion on steel is important in the transportation and infrastructure industries. Many nondestructive testing (NDT) methods have been applied to this inspection need. To overcome the existing limitations of traditional NDT methods, integrated NDT techniques have also been developed. To this end, the integration of microwave and thermography, referred to as active microwave thermography (AMT), is proposed as a potential NDT tool for detection and characterization of corrosion on steel bars. This method utilizes microwave energy to provide heat excitation. Subsequently, a thermal camera is used to monitor the thermal surface profile. This paper presents preliminary simulations and measurements of AMT as a potential method for corrosion detection and characterization.

Health monitoring of infrastructure is very important in the transportation and infrastructure i... more Health monitoring of infrastructure is very
important in the transportation and infrastructure industries.
Many nondestructive testing (NDT) techniques have been applied
for structural health monitoring including microwave NDT,
ultrasound, thermography, etc. Due to the complex materials
(composites, concrete, etc.) commonly used, it may be difficult to
thoroughly inspect a structure using one method alone. Thus,
hybrid NDT methods have also been developed. Recently, the
integration of microwave NDT and thermography, herein
referred to as Active Microwave Thermography (AMT), has also
been considered as a potential structural health monitoring tool.
This hybrid method uses microwave energy to heat a structure of
interest, and then the thermal surface profile is measured using a
thermal camera. This paper investigates the potential of AMT to
inspect rehabilitated cement-based structures. Preliminary
simulations and measurements provided herein indicate that
AMT has the potential to detect delaminations under carbon
fiber patches bonded to concrete.

Inspection of carbon fiber reinforced polymer (CFRP) composites is very important in the aeronau... more Inspection of carbon fiber reinforced polymer
(CFRP) composites is very important in the aeronautical and
transportation industries. Many nondestructive testing (NDT)
techniques have been applied for health monitoring including
ultrasound, thermography, etc. Although thermography has been
widely used for this purpose, it often requires powerful heat
lamps which may increase the risk of (thermal) damage to the
structure under test. Thus, hybrid NDT methods have also been
developed. Recently, the integration of microwave heating and
thermography, herein referred to as Active Microwave
Thermography (AMT), has also been considered as a potential
health monitoring tool for infrastructure. This hybrid method
uses microwave energy to heat a structure of interest, and
subsequently the thermal surface profile is measured using a
thermal camera. This paper investigates the potential of AMT for
inspection of CFRP-rehabilitated airframes. Preliminary
simulations and measurements indicate that AMT has the
potential to detect disbonds under carbon fiber patches bonded
to aluminum.

In this article, an integrated broadband planar monopole antenna with extra frequency bands is pr... more In this article, an integrated broadband planar monopole
antenna with extra frequency bands is presented. The proposed antenna
consists of a simple square shaped planar. The center part of the plate
can be removed with negligible effect on reflection coefficient. To
improve the impedance matching of the planar antenna, the lower corner
of the antenna is removed. Also, the higher cut-off frequency is
enhanced by an additional strip at the top corner of the plate. By inserting
additional strips in the path of the notched part of the plate, integrated
broadband antenna with extra bands can be attained which leads
to dual- and triple-band antenna. The additional bands cover 1.71–1.88
(DCS) and 2.4–2.48 (WLAN). Simulation and measurement results of the
proposed antenna agree well and show good performance for multiband
behavior.

IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, Jun 2012

A small-size microstrip-fed multi-band planar monopole antenna is presented. The base of the prop... more A small-size microstrip-fed multi-band planar monopole antenna is presented. The base of the proposed antenna is a diamond-shapedpatch (DSP) that covers the ultrawideband (UWB) frequency range. To create a multi-band antenna, several narrow strips, acting as resonance paths, can be integrated with the DSP antenna. It is shown that by removing the centre part of the DSP antenna, without distorting the UWB behavior, quarter-wavelength strips can be added to the notched region. This will not affect the dimension of the base antenna. The designed quad-band antenna has a substrate size of 16 22 mm and covers the frequency bands 1.3, 1.8, 2.4 and 3.1-10.6 GHz which includes GPS, GSM, WLAN and UWB. Dual-, triple-and quad-band antennas are simulated and good results are obtained. The antennas have omnidirectional and stable radiation patterns across all the relevant bands. Moreover, relatively consistent group delays across the UWB frequencies are noticed for the base, dual-and triple-band antennas, and slightly distorted for the quad-band antenna. A prototype of the quad-band antenna is fabricated and measured results are compared with simulated results. Index Terms-Monopole antenna, multi-band antenna, ultrawideband (UWB) antenna, wireless communication frequencies.

IET Microwaves, Antennas & Propagation, Nov 2012

The authors present a new optimisation method for pattern synthesis of multi-feed reflector anten... more The authors present a new optimisation method for pattern synthesis of multi-feed reflector antennas in this study. By using an invasive weed optimisation (IWO) algorithm, shaped beam antennas are designed. The results of the IWO algorithm for the synthesis of cosecant squared and contoured beam patterns are presented and compared with particle swarm optimisation algorithm results. The far-field radiation patterns of reflector antennas, fed by linear and planar array of conical horn antennas, are provided by a physical optics and the error between desired and provided radiation patterns is calculated by a root mean square method. The results show that the IWO algorithm, which provides good convergence, is stable and adaptive-to-change for different boundary conditions in pattern synthesis applications.

In this article, an integrated broadband planar monopole antenna with extra frequency bands is pr... more In this article, an integrated broadband planar monopole antenna with extra frequency bands is presented. The proposed antenna consists of a simple square shaped planar. The center part of the plate can be removed with negligible effect on reflection coefficient. To improve the impedance matching of the planar antenna, the lower corner of the antenna is removed. Also, the higher cut-off frequency is enhanced by an additional strip at the top corner of the plate. By inserting additional strips in the path of the notched part of the plate, integrated broadband antenna with extra bands can be attained which leads to dual- and triple-band antenna. The additional bands cover 1.71–1.88 (DCS) and 2.4–2.48 (WLAN). Simulation and measurement results of the proposed antenna agree well and show good performance for multiband behavior.

In this paper, a method is proposed to find the suitable antenna for a GSM urban macro cell cover... more In this paper, a method is proposed to find the suitable antenna for a GSM urban macro cell covered by a base transceiver station (BTS) mounted on high altitude platform (HAP) at the sfratosphere layer. To this end, an ideal cosine shape radiation pattern raised to the power of N is applied to select the appropriate antenna for achieving the optimum coverage. The optimum selection is based on minimizing the blind area, having less overlapped to total area ratio, and increasing the total coverage area, simultaneously. Our proposed scheme has two degrees of freedom; first, the values of N determining the directivity and half power beam width (HPBW), and second the angle a denoting to the mechanical tilt of the antenna elements. To find the optimum pair of (N, a), several simulations are done and the corresponding footprint contours are depicted. Simulation results show that utilizing three ideal cosine function antennas with N = 9 installed by a = 38 degrees of mechanical tilt with respect to the normal is optimum for a macro cell coverage in an urban area by using HAPs located at 17 km altitude.

IEEE LAPC 2011, 2011

This paper provides a dual-band printed wide slot microstrip-fed antenna. The proposed antenna co... more This paper provides a dual-band printed wide slot microstrip-fed antenna. The proposed antenna consists of a Ushaped radiating patch, a T-shaped monopole path and a Pentagonal-shaped wide slot in the ground plane. The dual-band antenna can cover both 2.4 GHz (WLAN) and 3.1-10.6 GHz (UWB) frequency ranges. The antenna size is 28 × 28 × 1 mm 3 which fabricated on a FR4 substrate. The simulation and measured results of the proposed antenna are presented and show good agreement in reflection coefficient and radiation patterns.

IEEE LAPC 2011, 2011

This paper presents a broadband printed circularly polarized monopole antenna. The base antenna c... more This paper presents a broadband printed circularly polarized monopole antenna. The base antenna consists of a falcate-shaped monopole antenna which provides 43% axial ratio bandwidth. By inserting a falcate-shaped slot in the base patch, 56% axial ratio is obtained. Moreover, inserting a slot in the base patch has no effect on the impedance bandwidth of the original structure. The proposed antenna dimension is 40 × 46 mm 2 and is fabricated on 1 mm FR4 substrate. The simulated return loss and axial ratio bandwidth of the antenna structure with and without the falcate shaped slot are presented and compared. Moreover, circular polarization radiation patterns of the proposed antenna are presented.

IEEE EuCAP 2012, 2012

In this paper, a new optimization algorithm to design shaped beam antenna is proposed. It is show... more In this paper, a new optimization algorithm to design shaped beam antenna is proposed. It is shown that by using offset parabolic reflector antenna and a linear array of horn antennas with one-wavelength spacing in focal point, Invasive Weed Optimization (IWO) algorithm can be used for amplitude and/or phase of source antennas to provide desired cosecant squared radiation patterns. To achieve a simple cosecant squared radiation pattern, amplitudes and phases of 11 source antennas (22 parameters) are optimized with no constraint by IWO and the results are compared with Particle Swarm Optimization (PSO) algorithm. Convergence diagram and radiation pattern results confirm the capability of IWO algorithm in shaped beam antenna design.

IEEE EuCAP 2012, 2012

A new method to design a cosecant squared radiation pattern in a shaped reflector antenna is prop... more A new method to design a cosecant squared radiation pattern in a shaped reflector antenna is proposed. Surface of the proposed reflector antenna is expanded by modified Jacobi polynomials. The expansion coefficients are optimized by using particle swarm optimization (PSO) algorithm to achieve desired cosecant squared radiation pattern in elevation plane and a narrow pencil beam radiation pattern in azimuth plane. The antenna is analyzed by physical optics (PO) method.

Microwave & RF, Apr 2013

This compact, circularly polarized, dual-band antenna provides sufficient bandwidth making it ide... more This compact, circularly polarized, dual-band antenna provides sufficient bandwidth making it ideal for GSM and UMTS base-station applications.

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Mar 2013

In this article, a dual-band WLAN/ultrawideband (UWB) printed wide slot microstrip-fed antenna is... more In this article, a dual-band WLAN/ultrawideband (UWB) printed wide slot microstrip-fed antenna is presented for multi-input multi-output (MIMO)/diversity applications. The proposed antenna consists of a U-shaped patch, a T-shaped monopole path, and a pentagonal wide slot in the ground plane. The antenna is designed to cover both the WLAN (2.4-2.485 GHz) and UWB (3.1-10.6 GHz) ranges, with value of S 11 below À10 dB. The antenna is constructed on a FR4 substrate with overall dimensions of 28 Â 28 Â 1 mm 3 . It is shown that the proposed dual-band antenna is suitable for diversity polarization applications. The simulation results show that the different configurations of the antenna in the MIMO/diversity have good Sparameters over the operating frequency bands. The simulation and measured results of the proposed dual-band antenna as well as that of the MIMO/diversity antenna configuration agree well. V C 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:461-465, 2013; View this article online at wileyonlinelibrary.com.

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Jul 2011

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, May 2012

filter occupies a small size of 8.7 mm by 2.4 mm. For the measurement, a 5-mm long microstrip fee... more filter occupies a small size of 8.7 mm by 2.4 mm. For the measurement, a 5-mm long microstrip feed line is added at both input and output. demonstrates the EM-simulated and experimental results of the proposed filter, where excellent agreement is obtained. The measured insertion loss is found to be less than 0.8 dB at the center frequency of the UWB passband. The measured return loss is better than 13 dB over the whole UWB passband. The filter shows the two new transmission zeros at the lower and upper edges of the desired passband, which enhanced the selectivity of the lower and the upper skirts of the UWB passband.