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Papers by yashar zehforoosh

A new design of microstrip slot antenna with switchable single and dual band filtering functions ... more A new design of microstrip slot antenna with switchable
single and dual band filtering functions for ultrawideband
(UWB) applications is presented in this letter. To create filtering
quality, in the proposed structure radiating patch is modified embedding
two T-shaped stubs into the radiating patch and also using coupling
parasitic element on the ground plane. The measured
impedance bandwidth for VSWR <2 is spread in frequency range of
3–16.9 GHz with a fractional bandwidth of 139.7% while filtering the
interference with C-band and wireless local area network systems at
3.4–4.28 GHz and 5.21–6.36 GHz, respectively. Introducing PIN
diodes switches to the antenna structure has added an additional
merit to the antenna performance which is switchable single/dual
band filtering operation. The designed antenna has a simple structure
with a very small size of 20 3 20 mm2 while presenting consistent
almost omnidirectional radiation characteristics at its vast frequency
range of operation.

In this article, we propose a compact cpw-fed ultra-wideband (UWB) antenna with dual band-notched... more In this article, we propose a compact cpw-fed ultra-wideband
(UWB) antenna with dual band-notched characteristics. The dual
band-notched are achieved by using two stepped impedance resonators.
The measured results show that the proposed antenna has an impedance
bandwidth from 2.97 to 10.7 GHz (113%), defined by VSWR<2, with
two notched bands, covering all the WiMAX (3.3–3.6 GHz), WLAN (5.2–
5.8 GHz), the antenna has a small size (20 3 20 3 1.6 mm3), and
almost stable omnidirectional radiation pattern. The proposed antenna
is designed, simulated, fabricated, and tested, and the measured results
are in good agreement with the simulations.

—A novel printed star-triangular fractal microstrip-fed monopole antenna with semielliptical grou... more —A novel printed star-triangular fractal microstrip-fed monopole antenna with semielliptical ground plane is presented for super-wideband (SWB) applications. In comparison to the previous SWB and fractal antennas, the antenna dimension has a compact size of mm. The antenna operates over the frequency band between 1–30 GHz for VSWR 2. The design process of the proposed structure for improving of the impedance bandwidth and measured results has been presented and discussed. The simulated and measured results are in good agreement.

An electromagnetically coupled elliptical antenna for UWB systems with a parasitic element to rej... more An electromagnetically coupled elliptical antenna for
UWB systems with a parasitic element to reject band of 5–5.9 GHz is
presented. The triangular cuts in parasitic element provide a good control
of bandwidth. A slot antenna inside the parasitic element has been
introduced to stimulate the rejected band (5–5.9 GHz) separately. Proposed
structure has printed on a substrate of FR4 with dimensions of 24
3 22.5 3 1 mm3. Measurement results prove the functionality of the
proposed structure.

We propose a four-channel plasmonic demultiplexer based on gold–air–gold structure. To do so, an ... more We propose a four-channel plasmonic demultiplexer based on gold–air–gold structure.
To do so, an add-drop filter is first proposed consisting of an H-shaped resonant cavity, which is
designed to drop a distinct wavelength to other waveguides. Since the selected wavelength depends
on the structural parameters of the resonant cavity, two- and four-channel demultiplexers are presented
by adding H-shape cavities with different sizes. The results of numerical simulations show
that for the total structure, spacing about 50 nm and an average transmission more than 95% for
channels are obtained. The proposed device exhibits high-transmission efficiency along with the
low channel spacing.

Abstract—The laminar field and heat transfer enhancement of forced convection in various counterf... more Abstract—The laminar field and heat transfer enhancement of forced convection in various counterflow porous channels with a joint aluminum plate was studied, using control volume technique and SIMPLE procedure for the velocity-pressure Coupling. Hydrodynamic and heat transfer results are reported for three configurations:(1) nonporous channels (NPC)(2) both channels filled by porous structure (BPC), and (3) only the channel contains hot fluid, filled by porous structure and other one is nonporous (HPC).

The letter presents the results of a novel miniature fractal monopole antenna that exhibits ultra... more The letter presents the results of a novel miniature fractal monopole antenna that exhibits ultra wideband (UWB) performance. The unique fractal patch generates multiple resonances that results in significant improvement in the antenna's impedance bandwidth of 152%. The antenna essentially radiates omni-directionally and its measured performance exceeds the UWB specifications defined by the Federal Communications Commission (FCC).

... Yashar Zehforoosh is with the Department of Electrical Engineering, Urmia branch, Islamic Aza... more ... Yashar Zehforoosh is with the Department of Electrical Engineering, Urmia branch, Islamic Azad University, Urmia, Iran. Page 2. 15 5 10 15 20 25 30 -40 -35 -30 -25 -20 -15 -10 -5 0 Frequency (GHz) ... Yashar Zehforoosh was born in Urmia, Iran in 1981. He received his M.Sc. ...

Microwave and …, 2011

Abstract This article presents the results of a novel triangular monopole antenna that exhibits m... more Abstract This article presents the results of a novel triangular monopole antenna that exhibits multioctave performance. This modification significantly improves the antenna&amp;amp;amp;#x27;s impedance bandwidth by 167% over an ultrawideband frequency. The antenna&amp;amp;amp;#x27;s simulated return-loss and radiation patterns show very good correlation with the fabricated antenna&amp;amp;amp;#x27;s measured results.© 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53: 10–14, 2011; View this article online at wileyonlinelibrary. com. DOI 10.1002/mop. 25673

Microwave and …, 2011

Abstract This article presents the results of a novel triangular monopole antenna that exhibits m... more Abstract This article presents the results of a novel triangular monopole antenna that exhibits multioctave performance. This modification significantly improves the antenna&amp;#x27;s impedance bandwidth by 158% over an ultra-wideband frequency. The antenna&amp;#x27;s simulated return loss and radiation patterns show very good correlation with the fabricated antenna&amp;#x27;s measured results.© 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary. com. DOI 10.1002/mop. 26093

ieeexplore.ieee.org

Abstract In this paper, we present a novel design of printed monopole antenna for UWB application... more Abstract In this paper, we present a novel design of printed monopole antenna for UWB applications. The radiating element of the proposed antenna is composed of an octagonal patch fed by a 50 ohm microstrip. It has a very compact size of 20mm× 12mm, which can be integrated easily with other RF front-end circuits. The antenna parameters and performances have been investigated through a large amount of EM simulations. It has been demonstrated that the proposed antenna provides an ultra wide bandwidth from 2.95 GHz to 13.35 GHz, ...

Far East Journal of Applied …, Jan 1, 2007

Abstract As wireless communication applications require more and more bandwidth, the demand for w... more Abstract As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. In this paper, first we review the ultra wideband communication, the history of microstrip antennas and applications, then the effect of parasitic patches and multiresonators are presented. This paper introduces two microstrip antennas for Ultra Wideband 3.1-10.6 GHz communications. In the first antenna, three multiresonator patches are used and in the second antenna four patches are placed as ...

Proceedings of the 5th …, Jan 1, 2006

As wireless communication applications require more and more bandwidth, the demand for wideband a... more As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz .This paper presents some of the work carried out within ULTRAWAVES in the area of antenna design and analysis. Two antennas have been designed, optimized and simulated using Stacked Multiresonator patches. In addition results and conclusions are presented.

WSEAS Transactions on …, Jan 1, 2006

As wireless communication applications require more and more bandwidth, the demand for wideband a... more As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz .In this paper we introduce a new multilayer microstrip antenna for ultra wideband applications. In order to achieve suitable bandwidth, the antenna size is fine for mobile applications. The antenna is designed, optimized and simulated using Ansoft designer.

PIERS Online, Jan 1, 2006

As wireless communication applications require more and more bandwidth, the demand for wideband a... more As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz.This paper presents a work carried out within UL-TRAWAVES in the area of antenna design and analysis. A new multilayer microstrip antenna is introduced using Stacked Multiresonator patches. In order to achieve suitable bandwidth, the antenna size is fine for mobile applications. The antenna is designed, optimized and simulated using Ansoft designer. In addition results and conclusions are presented.

A new design of microstrip slot antenna with switchable single and dual band filtering functions ... more A new design of microstrip slot antenna with switchable
single and dual band filtering functions for ultrawideband
(UWB) applications is presented in this letter. To create filtering
quality, in the proposed structure radiating patch is modified embedding
two T-shaped stubs into the radiating patch and also using coupling
parasitic element on the ground plane. The measured
impedance bandwidth for VSWR <2 is spread in frequency range of
3–16.9 GHz with a fractional bandwidth of 139.7% while filtering the
interference with C-band and wireless local area network systems at
3.4–4.28 GHz and 5.21–6.36 GHz, respectively. Introducing PIN
diodes switches to the antenna structure has added an additional
merit to the antenna performance which is switchable single/dual
band filtering operation. The designed antenna has a simple structure
with a very small size of 20 3 20 mm2 while presenting consistent
almost omnidirectional radiation characteristics at its vast frequency
range of operation.

In this article, we propose a compact cpw-fed ultra-wideband (UWB) antenna with dual band-notched... more In this article, we propose a compact cpw-fed ultra-wideband
(UWB) antenna with dual band-notched characteristics. The dual
band-notched are achieved by using two stepped impedance resonators.
The measured results show that the proposed antenna has an impedance
bandwidth from 2.97 to 10.7 GHz (113%), defined by VSWR<2, with
two notched bands, covering all the WiMAX (3.3–3.6 GHz), WLAN (5.2–
5.8 GHz), the antenna has a small size (20 3 20 3 1.6 mm3), and
almost stable omnidirectional radiation pattern. The proposed antenna
is designed, simulated, fabricated, and tested, and the measured results
are in good agreement with the simulations.

—A novel printed star-triangular fractal microstrip-fed monopole antenna with semielliptical grou... more —A novel printed star-triangular fractal microstrip-fed monopole antenna with semielliptical ground plane is presented for super-wideband (SWB) applications. In comparison to the previous SWB and fractal antennas, the antenna dimension has a compact size of mm. The antenna operates over the frequency band between 1–30 GHz for VSWR 2. The design process of the proposed structure for improving of the impedance bandwidth and measured results has been presented and discussed. The simulated and measured results are in good agreement.

An electromagnetically coupled elliptical antenna for UWB systems with a parasitic element to rej... more An electromagnetically coupled elliptical antenna for
UWB systems with a parasitic element to reject band of 5–5.9 GHz is
presented. The triangular cuts in parasitic element provide a good control
of bandwidth. A slot antenna inside the parasitic element has been
introduced to stimulate the rejected band (5–5.9 GHz) separately. Proposed
structure has printed on a substrate of FR4 with dimensions of 24
3 22.5 3 1 mm3. Measurement results prove the functionality of the
proposed structure.

We propose a four-channel plasmonic demultiplexer based on gold–air–gold structure. To do so, an ... more We propose a four-channel plasmonic demultiplexer based on gold–air–gold structure.
To do so, an add-drop filter is first proposed consisting of an H-shaped resonant cavity, which is
designed to drop a distinct wavelength to other waveguides. Since the selected wavelength depends
on the structural parameters of the resonant cavity, two- and four-channel demultiplexers are presented
by adding H-shape cavities with different sizes. The results of numerical simulations show
that for the total structure, spacing about 50 nm and an average transmission more than 95% for
channels are obtained. The proposed device exhibits high-transmission efficiency along with the
low channel spacing.

Abstract—The laminar field and heat transfer enhancement of forced convection in various counterf... more Abstract—The laminar field and heat transfer enhancement of forced convection in various counterflow porous channels with a joint aluminum plate was studied, using control volume technique and SIMPLE procedure for the velocity-pressure Coupling. Hydrodynamic and heat transfer results are reported for three configurations:(1) nonporous channels (NPC)(2) both channels filled by porous structure (BPC), and (3) only the channel contains hot fluid, filled by porous structure and other one is nonporous (HPC).

The letter presents the results of a novel miniature fractal monopole antenna that exhibits ultra... more The letter presents the results of a novel miniature fractal monopole antenna that exhibits ultra wideband (UWB) performance. The unique fractal patch generates multiple resonances that results in significant improvement in the antenna's impedance bandwidth of 152%. The antenna essentially radiates omni-directionally and its measured performance exceeds the UWB specifications defined by the Federal Communications Commission (FCC).

... Yashar Zehforoosh is with the Department of Electrical Engineering, Urmia branch, Islamic Aza... more ... Yashar Zehforoosh is with the Department of Electrical Engineering, Urmia branch, Islamic Azad University, Urmia, Iran. Page 2. 15 5 10 15 20 25 30 -40 -35 -30 -25 -20 -15 -10 -5 0 Frequency (GHz) ... Yashar Zehforoosh was born in Urmia, Iran in 1981. He received his M.Sc. ...

Microwave and …, 2011

Abstract This article presents the results of a novel triangular monopole antenna that exhibits m... more Abstract This article presents the results of a novel triangular monopole antenna that exhibits multioctave performance. This modification significantly improves the antenna&amp;amp;amp;#x27;s impedance bandwidth by 167% over an ultrawideband frequency. The antenna&amp;amp;amp;#x27;s simulated return-loss and radiation patterns show very good correlation with the fabricated antenna&amp;amp;amp;#x27;s measured results.© 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53: 10–14, 2011; View this article online at wileyonlinelibrary. com. DOI 10.1002/mop. 25673

Microwave and …, 2011

Abstract This article presents the results of a novel triangular monopole antenna that exhibits m... more Abstract This article presents the results of a novel triangular monopole antenna that exhibits multioctave performance. This modification significantly improves the antenna&amp;#x27;s impedance bandwidth by 158% over an ultra-wideband frequency. The antenna&amp;#x27;s simulated return loss and radiation patterns show very good correlation with the fabricated antenna&amp;#x27;s measured results.© 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary. com. DOI 10.1002/mop. 26093

ieeexplore.ieee.org

Abstract In this paper, we present a novel design of printed monopole antenna for UWB application... more Abstract In this paper, we present a novel design of printed monopole antenna for UWB applications. The radiating element of the proposed antenna is composed of an octagonal patch fed by a 50 ohm microstrip. It has a very compact size of 20mm× 12mm, which can be integrated easily with other RF front-end circuits. The antenna parameters and performances have been investigated through a large amount of EM simulations. It has been demonstrated that the proposed antenna provides an ultra wide bandwidth from 2.95 GHz to 13.35 GHz, ...

Far East Journal of Applied …, Jan 1, 2007

Abstract As wireless communication applications require more and more bandwidth, the demand for w... more Abstract As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. In this paper, first we review the ultra wideband communication, the history of microstrip antennas and applications, then the effect of parasitic patches and multiresonators are presented. This paper introduces two microstrip antennas for Ultra Wideband 3.1-10.6 GHz communications. In the first antenna, three multiresonator patches are used and in the second antenna four patches are placed as ...

Proceedings of the 5th …, Jan 1, 2006

As wireless communication applications require more and more bandwidth, the demand for wideband a... more As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz .This paper presents some of the work carried out within ULTRAWAVES in the area of antenna design and analysis. Two antennas have been designed, optimized and simulated using Stacked Multiresonator patches. In addition results and conclusions are presented.

WSEAS Transactions on …, Jan 1, 2006

As wireless communication applications require more and more bandwidth, the demand for wideband a... more As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz .In this paper we introduce a new multilayer microstrip antenna for ultra wideband applications. In order to achieve suitable bandwidth, the antenna size is fine for mobile applications. The antenna is designed, optimized and simulated using Ansoft designer.

PIERS Online, Jan 1, 2006

As wireless communication applications require more and more bandwidth, the demand for wideband a... more As wireless communication applications require more and more bandwidth, the demand for wideband antennas increases as well. For instance, the ultra wideband radio (UWB) utilizes the frequency band of 3.1-10.6 GHz.This paper presents a work carried out within UL-TRAWAVES in the area of antenna design and analysis. A new multilayer microstrip antenna is introduced using Stacked Multiresonator patches. In order to achieve suitable bandwidth, the antenna size is fine for mobile applications. The antenna is designed, optimized and simulated using Ansoft designer. In addition results and conclusions are presented.