ammar Nadal Shareef | Al-Muthanna University (Iraq) (original) (raw)

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Papers by ammar Nadal Shareef

Metamaterials or left-handed materials are man-made structures. They have properties like negativ... more Metamaterials or left-handed materials are man-made structures. They have properties like negative refractive index that is not found in natural materials. Metamaterials that is designed by placing electromagnetic resonators like split ring resonators (SRRs) in a periodic array is among the most popular designs. Split ring resonators when placed next to antennas as a cover, it will improve the gain of the antenna. Split ring resonator when slotted on patches, it causes a size reduction. Microstrip patch antennas have become one of the most popular antennas because they have many advantages such as low-profile, light weight, and low cost of fabrication. Designing of microstrip patches are utilized from fractal geometry. Fractal shapes exhibit antennas more improved in its parameters. In this thesis, six classical and four fractal unit cell metamaterials are designed and their parameters are calculated using retrieval method by HFSSV13 code for electromagnetic structure simulation. Permittivity, permeability, and negative refractive index are calculated. These shapes show left-handed behavior in their resonance frequencies. The study of effect of metamaterial unit cells on antenna parameters lies in two categories, gain enhancement and size reduction. Meta-cover of classical and fractal unit cells is placed above Quadruple Koch, Peano, and Snowflake antennas. Good results of gain enhancement and side lobe reduction are obtained. Enhancement of some models of fractal meta-cover equals 5 dB. Split ring resonator and Hilbert ring are slotted on antenna patch and ground plane of the antenna respectively. Two models are proposed, First iteration of Peano and Snowflake antennas. A good result of size reduction is obtained. The reduction in Peano antenna equals to 41%. Quadruple Koch and Peano antennas are studied experimentally. These models are fabricated and measured using vector network analyzer. Good agreement of measured and calculated results is obtained. In the future work more than two layers will be investigated with different angles relative to the antenna plane.

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Bandwidth of the operating frequency of an antenna is an important parameter in antenna design. I... more Bandwidth of the operating frequency of an antenna is an important parameter in antenna design. It is strongly related to the performance of data rate. Hence to get more data rates for mobile applications, much higher bandwidths are needed. Frequency bands lies above 6 GHz, characterized by more continuous frequency range than bands below 6 GHz. This gives more chance to meet these requirements. To this end Pentagon fractal antenna is proposed here. It has multiband behavior and very good gain and directivity with excellent efficiency which make it very suitable for above 6 GHz applications.

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Size reduction of square patch antenna is proposed using meta-fractal technique. This technique i... more Size reduction of square patch antenna is proposed using meta-fractal technique. This technique implies adding fractal shape (Peano shape here) to the classical square antenna to reduce its size and then a complementary split ring resonator (CSRR) is slotted on the patch as a defect. The defect enforces the antenna to behave as meta-material in a specific frequency range. Peano fractal antenna has three resonances. The complementary split ring resonator affects the upper two x-band frequencies and makes the antenna resonates at 9.5 GHz and 10 GHz rather than 10 GHz and 10.89 GHz. Shifting the resonances of the antenna means size reduction is obtained. Calculations are carried using (HFSS) software, which is based on finite element modeling. Good convergence obtained of measurement and calculated results.

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Engineering and Technology Journal, 2015

Advanced materials are artificial structure materials that exhibit properties not found in nature... more Advanced materials are artificial structure materials that exhibit properties not found in nature. Material that has a negative refractive index (left-handed materials) is found to get a lot of interest in the literatures. Controlling the geometry of classical material may lead to have a negative refractive index in a certain frequency range. In this paper, we utilized from fractal geometry in our design. A Sierpinski Carpet fractal model is proposed. Calculations show that this model has a negative refractive index in the frequency range 7.5 GHz – 16.5 GHz. Wide band behavior of this model refers to its fractal shape.

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International Journal of Wireless and Microwave Technologies, 2015

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IOSR Journal of Electrical and Electronics Engineering, 2014

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ABSTRACT

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Abstract: In this paper, fractal Koch antenna is proposed. Complementary split ring resonator (C... more Abstract:
In this paper, fractal Koch antenna is proposed. Complementary split ring resonator (CSRR) has the shape of Hilbert Curve is added to the ground plane as a defect. This embedded shape makes the patch behave as left-handed material in certain frequency band. Koch antenna has two resonance frequencies. The resonance frequencies located at 5.32 GHz and 11 GHz. Adding Hilbert ring to the ground plane makes the antenna resonates at 4.6 GHz and 8.7 GHz. Lowering the resonance frequencies cause a reduction in antenna size. The simulated results have been done using (HFSS) software, which is based on finite element modeling.

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Size reduction of square patch antenna is proposed using meta-fractal technique. This technique i... more Size reduction of square patch antenna is proposed using meta-fractal technique. This technique implies adding fractal shape (Peano shape here) to the classical square antenna to reduce its size and then a complementary split ring resonator (CSRR) is slotted on the patch as a defect. The defect enforces the antenna to behave as meta-material in a specific frequency range. Peano fractal antenna has three resonances. The complementary split ring resonator affects the upper two x-band frequencies and makes the antenna resonates at 9.5 GHz and 10 GHz rather than 10 GHz and 10.89 GHz. Shifting the resonances of the antenna means size reduction is obtained. Calculations are carried using (HFSS) software, which is based on finite element modeling. Good convergence obtained of measurement and calculated results.

Bookmarks Related papers MentionsView impact

Advanced materials are artificial structure materials that exhibit properties not found in nature... more Advanced materials are artificial structure materials that exhibit properties not found in nature. Material that has a negative refractive index (left-handed materials) is found to get a lot of interest in the literatures. Controlling the geometry of classical material may lead to have a negative refractive index in a certain frequency range. In this paper, we utilized from fractal geometry in our design. A Sierpinski Carpet fractal model is proposed. Calculations show that this model has a negative refractive index in the frequency range 7.5 GHz – 16.5 GHz. Wide band behavior of this model refers to its fractal shape.

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Negative index of refraction has attracted a great attention in literatures. These materials are ... more Negative index of refraction has attracted a great attention in literatures. These materials are artificial structures named metamaterials has characteristics not found in nature. Microstrip antennas covered by metamaterial are very interesting areas of study. In this paper fractal Peano shape antenna is proposed and covered by two layers of modified ring resonator. The results show an enhancement in Reflection Coefficients, gain, and directivity. Index Terms: Metamaterials, left handed materials, split ring resonators, negative refractive index, fractal antennas.

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Gain enhancement has attracted a great amount of attention in literatures. There were many ways, ... more Gain enhancement has attracted a great amount of attention in literatures. There were many ways, which were published to improve antenna gain. One of these ways is using Metamaterials. Materials that have negative refractive index are used to achieve this goal. These materials are artificial structures that exhibit characteristics not found in nature. Microstrip antennas covered by metamaterial are one of the interesting areas of study. Fractal shapes are used to improve antenna characteristics. Among these characteristics is antenna gain. In this paper fractal shape antenna is proposed and covered by new design of ring resonator to get enhancement in gain. The calculated result shows an enhancement in efficiency, gain, directivity and far field shapes. There is big agreement between simulation and measurements.

Bookmarks Related papers MentionsView impact

Metamaterials exhibiting negative index of refraction has attracted a great amount of attention i... more Metamaterials exhibiting negative index of refraction has attracted a great amount of attention in recent years. These materials are artificial structures that exhibit characteristics not found in nature. Microstrip antennas covered by metamaterial are one of the interesting areas of study. In this paper fractal shape antenna is proposed and covered by two layers of modified split ring resonator. The results shows an enhancement in Reflection Coefficients, gain, directivity and far field shapes.

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Bandwidth of the operating frequency of an antenna is an important parameter in antenna design. I... more Bandwidth of the operating frequency of an antenna is an important parameter in antenna design. It is strongly related to the performance of data rate. Hence to get more data rates for mobile applications, much higher bandwidths are needed. Frequency bands lies above 6 GHz, characterized by more continuous frequency range than bands below 6 GHz. This gives more chance to meet these requirements. To this end Pentagon fractal antenna is proposed here. It has multiband behavior and very good gain and directivity with excellent efficiency which make it very suitable for above 6 GHz applications.

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Thesis Chapters by ammar Nadal Shareef

Metamaterials or left-handed materials are man-made structures. They have properties like negati... more Metamaterials or left-handed materials are man-made structures.
They have properties like negative refractive index that is not found in
natural materials. Metamaterials that is designed by placing
electromagnetic resonators like split ring resonators (SRRs) in a periodic
array is among the most popular designs. Split ring resonators when
placed next to antennas as a cover, it will improve the gain of the antenna.
Split ring resonator when slotted on patches, it causes a size reduction.
Microstrip patch antennas have become one of the most popular
antennas because they have many advantages such as low-profile, light
weight, and low cost of fabrication. Designing of microstrip patches are utilized from fractal geometry. Fractal shapes exhibit antennas more
improved in its parameters.
In this thesis, six classical and four fractal unit cell metamaterials
are designed and their parameters are calculated using retrieval method
by HFSSV13 code for electromagnetic structure simulation. Permittivity,
permeability, and negative refractive index are calculated. These shapes
show left-handed behavior in their resonance frequencies. The study of effect of metamaterial unit cells on antenna
parameters lies in two categories, gain enhancement and size reduction.
Meta-cover of classical and fractal unit cells is placed above Quadruple
Koch, Peano, and Snowflake antennas. Good results of gain enhancement
and side lobe reduction are obtained. Enhancement of some models of
fractal meta-cover equals 5 dB. Split ring resonator and Hilbert ring are
slotted on antenna patch and ground plane of the antenna respectively.
Two models are proposed, First iteration of Peano and Snowflake
antennas. A good result of size reduction is obtained. The reduction in Peano antenna equals to 41%. Quadruple Koch and Peano antennas are
studied experimentally. These models are fabricated and measured using
vector network analyzer. Good agreement of measured and calculated
results is obtained. In the future work more than two layers will be
investigated with different angles relative to the antenna plane.

Bookmarks Related papers MentionsView impact

Metamaterials or left-handed materials are man-made structures. They have properties like negativ... more Metamaterials or left-handed materials are man-made structures. They have properties like negative refractive index that is not found in natural materials. Metamaterials that is designed by placing electromagnetic resonators like split ring resonators (SRRs) in a periodic array is among the most popular designs. Split ring resonators when placed next to antennas as a cover, it will improve the gain of the antenna. Split ring resonator when slotted on patches, it causes a size reduction. Microstrip patch antennas have become one of the most popular antennas because they have many advantages such as low-profile, light weight, and low cost of fabrication. Designing of microstrip patches are utilized from fractal geometry. Fractal shapes exhibit antennas more improved in its parameters. In this thesis, six classical and four fractal unit cell metamaterials are designed and their parameters are calculated using retrieval method by HFSSV13 code for electromagnetic structure simulation. Permittivity, permeability, and negative refractive index are calculated. These shapes show left-handed behavior in their resonance frequencies. The study of effect of metamaterial unit cells on antenna parameters lies in two categories, gain enhancement and size reduction. Meta-cover of classical and fractal unit cells is placed above Quadruple Koch, Peano, and Snowflake antennas. Good results of gain enhancement and side lobe reduction are obtained. Enhancement of some models of fractal meta-cover equals 5 dB. Split ring resonator and Hilbert ring are slotted on antenna patch and ground plane of the antenna respectively. Two models are proposed, First iteration of Peano and Snowflake antennas. A good result of size reduction is obtained. The reduction in Peano antenna equals to 41%. Quadruple Koch and Peano antennas are studied experimentally. These models are fabricated and measured using vector network analyzer. Good agreement of measured and calculated results is obtained. In the future work more than two layers will be investigated with different angles relative to the antenna plane.

Bookmarks Related papers MentionsView impact

Bandwidth of the operating frequency of an antenna is an important parameter in antenna design. I... more Bandwidth of the operating frequency of an antenna is an important parameter in antenna design. It is strongly related to the performance of data rate. Hence to get more data rates for mobile applications, much higher bandwidths are needed. Frequency bands lies above 6 GHz, characterized by more continuous frequency range than bands below 6 GHz. This gives more chance to meet these requirements. To this end Pentagon fractal antenna is proposed here. It has multiband behavior and very good gain and directivity with excellent efficiency which make it very suitable for above 6 GHz applications.

Bookmarks Related papers MentionsView impact

Size reduction of square patch antenna is proposed using meta-fractal technique. This technique i... more Size reduction of square patch antenna is proposed using meta-fractal technique. This technique implies adding fractal shape (Peano shape here) to the classical square antenna to reduce its size and then a complementary split ring resonator (CSRR) is slotted on the patch as a defect. The defect enforces the antenna to behave as meta-material in a specific frequency range. Peano fractal antenna has three resonances. The complementary split ring resonator affects the upper two x-band frequencies and makes the antenna resonates at 9.5 GHz and 10 GHz rather than 10 GHz and 10.89 GHz. Shifting the resonances of the antenna means size reduction is obtained. Calculations are carried using (HFSS) software, which is based on finite element modeling. Good convergence obtained of measurement and calculated results.

Bookmarks Related papers MentionsView impact

Engineering and Technology Journal, 2015

Advanced materials are artificial structure materials that exhibit properties not found in nature... more Advanced materials are artificial structure materials that exhibit properties not found in nature. Material that has a negative refractive index (left-handed materials) is found to get a lot of interest in the literatures. Controlling the geometry of classical material may lead to have a negative refractive index in a certain frequency range. In this paper, we utilized from fractal geometry in our design. A Sierpinski Carpet fractal model is proposed. Calculations show that this model has a negative refractive index in the frequency range 7.5 GHz – 16.5 GHz. Wide band behavior of this model refers to its fractal shape.

Bookmarks Related papers MentionsView impact

International Journal of Wireless and Microwave Technologies, 2015

Bookmarks Related papers MentionsView impact

IOSR Journal of Electrical and Electronics Engineering, 2014

Bookmarks Related papers MentionsView impact

ABSTRACT

Bookmarks Related papers MentionsView impact

Abstract: In this paper, fractal Koch antenna is proposed. Complementary split ring resonator (C... more Abstract:
In this paper, fractal Koch antenna is proposed. Complementary split ring resonator (CSRR) has the shape of Hilbert Curve is added to the ground plane as a defect. This embedded shape makes the patch behave as left-handed material in certain frequency band. Koch antenna has two resonance frequencies. The resonance frequencies located at 5.32 GHz and 11 GHz. Adding Hilbert ring to the ground plane makes the antenna resonates at 4.6 GHz and 8.7 GHz. Lowering the resonance frequencies cause a reduction in antenna size. The simulated results have been done using (HFSS) software, which is based on finite element modeling.

Bookmarks Related papers MentionsView impact

Size reduction of square patch antenna is proposed using meta-fractal technique. This technique i... more Size reduction of square patch antenna is proposed using meta-fractal technique. This technique implies adding fractal shape (Peano shape here) to the classical square antenna to reduce its size and then a complementary split ring resonator (CSRR) is slotted on the patch as a defect. The defect enforces the antenna to behave as meta-material in a specific frequency range. Peano fractal antenna has three resonances. The complementary split ring resonator affects the upper two x-band frequencies and makes the antenna resonates at 9.5 GHz and 10 GHz rather than 10 GHz and 10.89 GHz. Shifting the resonances of the antenna means size reduction is obtained. Calculations are carried using (HFSS) software, which is based on finite element modeling. Good convergence obtained of measurement and calculated results.

Bookmarks Related papers MentionsView impact

Advanced materials are artificial structure materials that exhibit properties not found in nature... more Advanced materials are artificial structure materials that exhibit properties not found in nature. Material that has a negative refractive index (left-handed materials) is found to get a lot of interest in the literatures. Controlling the geometry of classical material may lead to have a negative refractive index in a certain frequency range. In this paper, we utilized from fractal geometry in our design. A Sierpinski Carpet fractal model is proposed. Calculations show that this model has a negative refractive index in the frequency range 7.5 GHz – 16.5 GHz. Wide band behavior of this model refers to its fractal shape.

Bookmarks Related papers MentionsView impact

Negative index of refraction has attracted a great attention in literatures. These materials are ... more Negative index of refraction has attracted a great attention in literatures. These materials are artificial structures named metamaterials has characteristics not found in nature. Microstrip antennas covered by metamaterial are very interesting areas of study. In this paper fractal Peano shape antenna is proposed and covered by two layers of modified ring resonator. The results show an enhancement in Reflection Coefficients, gain, and directivity. Index Terms: Metamaterials, left handed materials, split ring resonators, negative refractive index, fractal antennas.

Bookmarks Related papers MentionsView impact

Gain enhancement has attracted a great amount of attention in literatures. There were many ways, ... more Gain enhancement has attracted a great amount of attention in literatures. There were many ways, which were published to improve antenna gain. One of these ways is using Metamaterials. Materials that have negative refractive index are used to achieve this goal. These materials are artificial structures that exhibit characteristics not found in nature. Microstrip antennas covered by metamaterial are one of the interesting areas of study. Fractal shapes are used to improve antenna characteristics. Among these characteristics is antenna gain. In this paper fractal shape antenna is proposed and covered by new design of ring resonator to get enhancement in gain. The calculated result shows an enhancement in efficiency, gain, directivity and far field shapes. There is big agreement between simulation and measurements.

Bookmarks Related papers MentionsView impact

Metamaterials exhibiting negative index of refraction has attracted a great amount of attention i... more Metamaterials exhibiting negative index of refraction has attracted a great amount of attention in recent years. These materials are artificial structures that exhibit characteristics not found in nature. Microstrip antennas covered by metamaterial are one of the interesting areas of study. In this paper fractal shape antenna is proposed and covered by two layers of modified split ring resonator. The results shows an enhancement in Reflection Coefficients, gain, directivity and far field shapes.

Bookmarks Related papers MentionsView impact

Bandwidth of the operating frequency of an antenna is an important parameter in antenna design. I... more Bandwidth of the operating frequency of an antenna is an important parameter in antenna design. It is strongly related to the performance of data rate. Hence to get more data rates for mobile applications, much higher bandwidths are needed. Frequency bands lies above 6 GHz, characterized by more continuous frequency range than bands below 6 GHz. This gives more chance to meet these requirements. To this end Pentagon fractal antenna is proposed here. It has multiband behavior and very good gain and directivity with excellent efficiency which make it very suitable for above 6 GHz applications.

Bookmarks Related papers MentionsView impact

Metamaterials or left-handed materials are man-made structures. They have properties like negati... more Metamaterials or left-handed materials are man-made structures.
They have properties like negative refractive index that is not found in
natural materials. Metamaterials that is designed by placing
electromagnetic resonators like split ring resonators (SRRs) in a periodic
array is among the most popular designs. Split ring resonators when
placed next to antennas as a cover, it will improve the gain of the antenna.
Split ring resonator when slotted on patches, it causes a size reduction.
Microstrip patch antennas have become one of the most popular
antennas because they have many advantages such as low-profile, light
weight, and low cost of fabrication. Designing of microstrip patches are utilized from fractal geometry. Fractal shapes exhibit antennas more
improved in its parameters.
In this thesis, six classical and four fractal unit cell metamaterials
are designed and their parameters are calculated using retrieval method
by HFSSV13 code for electromagnetic structure simulation. Permittivity,
permeability, and negative refractive index are calculated. These shapes
show left-handed behavior in their resonance frequencies. The study of effect of metamaterial unit cells on antenna
parameters lies in two categories, gain enhancement and size reduction.
Meta-cover of classical and fractal unit cells is placed above Quadruple
Koch, Peano, and Snowflake antennas. Good results of gain enhancement
and side lobe reduction are obtained. Enhancement of some models of
fractal meta-cover equals 5 dB. Split ring resonator and Hilbert ring are
slotted on antenna patch and ground plane of the antenna respectively.
Two models are proposed, First iteration of Peano and Snowflake
antennas. A good result of size reduction is obtained. The reduction in Peano antenna equals to 41%. Quadruple Koch and Peano antennas are
studied experimentally. These models are fabricated and measured using
vector network analyzer. Good agreement of measured and calculated
results is obtained. In the future work more than two layers will be
investigated with different angles relative to the antenna plane.

Bookmarks Related papers MentionsView impact