Likaa Salim Yahya -

Assist. Prof.

Likaa Salim Yahya

Research Interests

Gender	FEMALE
Place of Work	Mosul Technical Institute
Position	Lecturer
Qualification	Ph.d
Speciality	Electrical Engineering /Communications
Email	likaasalim@ntu.edu.iq
Phone	07705207035
Address	Nineveh / Mosul, single, Mosul, Iraq

Academic Links

About Me

Publications

Characterization of a Split Circle Element for Microstrip Reflectarrays

Sep 1, 2023

Journal Journal of Telecommunications and Information Technology

publisher Instytut Łączności-Państwowy Instytut Badawczy

DOI https://doi.org/10.26636/jtit.2023.3.1363

Issue 3

A split circular element is proposed as a unit cell for reflectarray antennas. The unit cell is derived from a circle divided into four equal sectors. The radius of two oppositely located sectors is then scaled by a certain factor to form the proposed shape. The CST Microwave Studio Suite software simulator was used to investigate the performance of the proposed unit cell, which was evaluated using Floquet port excitation. The designed element’s reflection phase range was compared to that of a conventional circular patch. Four scenarios of varied substrate characteristics are investigated for the antenna to establish the best performance parameters. The simulations showed that a basic substrate with a thickness of 0.16 mm and a dielectric constant of 3.2, backed by a 3 mm foam with a dielectric constant of 1.05 and a scaling factor of 0.72 offers a wide phase range of 601.3◦ . The obtained phase slope is 76.37◦/mm or 134◦ /GHz.

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Dual-Band Folded Monopole MIMO Antennas with Enhanced Isolation

Mar 10, 2022

Journal Applied Computational Electromagnetics Society Journal(ACES)

publisher River Publisher

DOI https://doi.org/10.13052/2021.ACES.J.361208

Issue 12

Volume 36

In this paper, a compact dual-band multiple-input multiple-output (MIMO) diversity antenna is proposed. Each of the two MIMO antennas consists of two folded strips working as radiating elements that are fed by a microstrip line. The antennas operate in three WLAN bands: ISM 2.45 GHz, 5.25 GHz, and ISM 5.775 GHz. To improve the isolation at WLAN (2.4–2.48 GHz), two L-shaped slots are etched in the ground plane while a U-shaped slot is cut in the ground plane to enhance isolation at WLAN (5.15–5.35 GHz and 5.725–5.825 GHz). Three slots on the substrate between radiating patches are also employed for an extra reduction in the mutual coupling at 2.45 GHz. The antenna performance was examined by simulation employing CST Microwave Studio Software. The proposed antenna offers minimum isolation of more than 19.5 dB, a low envelope correlation coefficient (ECC) of less than 0.0016, and good radiation efficiency (∼∼80%) through the operating frequency bands. The antenna is compact, thin, and suitable for portable devices.

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A Crescent-Shaped Monopole MIMO Antennas with Improved Isolation for Dual-Band WLAN Applications

Dec 27, 2021

Journal Progress In Electromagnetics Research C

publisher EMW Publishing

DOI http://dx.doi.org/10.2528/PIERC21101503

Volume 117

A multi-input multi-output (MIMO) antenna system is presented for wireless devices operating at WLAN (2.45, 5.25, and 5.775 GHz) bands. Each of the two antennas in the MIMO system consists of a crescent-shaped monopole whose first part covers the 2.45 GHz band while its second part covers the 5.25 GHz and 5.775 GHz bands. The second part of the monopole is a slot etched in the protruded ground plane between the two antennas. A decoupling mechanism in the form of two interlaced ring-shaped slots is used. The proposed MIMO antenna system is designed on an FR4 substrate with overall dimensions of 40 × 47.5 × 1.5 mm and a small edge-to-edge spacing of 7.3 mm between two antennas. According to the measured results, the proposed design covers two frequency bands (2.2–2.83 GHz and 5.03–5.95 GHz) and has a mutual coupling of −20.78 dB at 2.45 GHz and −42.65 dB at 5.55 GHz. The proposed antenna’s performance in both simulations and testing indicates that it is a good choice for WLAN applications.

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Double-Monopole Crescent-Shaped Antennas with High Isolation for WLAN and WIMAX Applications

Oct 5, 2017

Journal Antenna Fundamentals for Legacy Mobile Applications and Beyond

publisher Springer, Cham

DOI https://doi.org/10.1007/978-3-319-63967-3_3

The mutual coupling between two closely spaced antennas and various techniques for its reduction are explained. Two configurations of a planar double antenna are proposed where one antenna is intended for WLAN and the other for WIMAX applications. Each antenna has the form of a crescent-shaped monopole. The lengths of the two radiating arcs are chosen for resonance at 2.45 GHz and 3.5 GHz to comply with the WLAN and WiMAX standards, respectively. The two monopoles have a small separation of 9 mm (0.0735 ;o at 2.45 GHz). A technique is proposed for reducing the mutual coupling between the two closely spaced antennas by etching a slot in each of the microstrip line feeding the two antennas. The slot length in each antenna is chosen such that it resonates at the operating frequency of the other antenna so that the frequency of the other antenna is notched out and lower coupling is achieved. Two configurations are investigated to obtain increased isolation between the two antennas. The simulations using CST Microwave Studio software show that the proposed methods can reduce the envelope correlation coefficient by 35-fold at the 2.45 GHz and 21-fold at the 3.5 GHz frequency bands.

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Modeling of Dual-Band Crescent-Shape Monopole Antenna for WLAN Applications

Apr 20, 2014

Journal International Journal of Electromagnetics and Applications

publisher Scientific & Academic Publishing

DOI doi:10.5923/j.ijea.20140402.01

Issue 4

Volume 2

Modeling of dual-band monopole antennas is investigated. A recently presented dual band crescent-shape monopole antenna for WLAN applications is modeled by an RLC equivalent circuit using two methods. In the first method, the input impedance is represented by the first Foster canonical form. The equivalent circuit parameters at resonance are extracted from either the input impedance or the reflection coefficient responses of the simulated antenna. In the second method, the input admittance of the proposed antenna is modeled as an SPICE–compatible equivalent circuit using vector fitting technique. The input impedance and reflection coefficient of the investigated antenna were obtained using CST Microwave Studio, and then were used to extract values of the lumped components of the equivalent circuit. The performances of the investigated methods are compared. Validities of the modeling methods for dual band antenna are verified using MATLAB and ADS softwares.

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Design and Analysis of Dual Band Crescent Shape Monopole Antenna for WLAN Applications

Feb 1, 2013

Journal International Journal of Electromagnetics and Applications

publisher Scientific & Academic Publishing

DOI doi:10.5923/j.ijea.20130304.05

Issue 3

Volume 4

A dual band crescent shape planar monopole antenna for wireless local area network (WLAN) application is proposed. The crescent antenna is evolved from an arc patch antenna. By adjusting the feed line position along the arc, two distinct bandwidths that meet the requirements for the WLAN standards can be obtained. The proposed antenna covers the frequency bands of the IEEE 802.11 a/b/g (2.4-2.48 GHz, 5.15-5.35 GHz, and 5.725-5.825 GHz). The proposed antenna is investigated using CST software package. The reflection coefficient, radiation pattern, gain and efficiency for various design parameters are investigated. Average gains of 2.3dBi and 3.98dBi are achieved in the lower and higher frequency band, respectively.

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Conferences