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Author

Ikbal Hossain

Bio: Ikbal Hossain is an academic researcher from National University of Malaysia. The author has contributed to research in topics: Monopole antenna & Antenna measurement. The author has an hindex of 2, co-authored 4 publications receiving 67 citations.

Papers
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Journal ArticleDOI
TL;DR: A new design and analysis of a wide-band double-negative metamaterial, considering a frequency range of 0.5 to 7 GHz, is presented, and good agreement is observed between the simulated and measured S parameters of the developed unit cell and array.
Abstract: A new design and analysis of a wide-band double-negative metamaterial, considering a frequency range of 0.5 to 7 GHz, is presented in this paper. Four different unit cells with varying design parameters are analyzed to evaluate the effects of the unit-cell size on the resonance frequencies of the metamaterial. Moreover, open and interconnected 2 × 2 array structures of unit cells are analyzed. The finite-difference time-domain (FDTD) method, based on the Computer Simulation Technology (CST) Microwave Studio, is utilized in the majority of this investigation. The experimental portion of the study was performed in a semi-anechoic chamber. Good agreement is observed between the simulated and measured S parameters of the developed unit cell and array. The designed unit cell exhibits negative permittivity and permeability simultaneously at S-band (2.95 GHz to 4.00 GHz) microwave frequencies. In addition, the designed unit cell can also operate as a double-negative medium throughout the C band (4.00 GHz to 4.95 GHz and 5.00 GHz to 5.57 GHz). At a number of other frequencies, it exhibits a single negative value. The two array configurations cause a slight shift in the resonance frequencies of the metamaterial and hence lead to a slight shift of the single- and double-negative frequency ranges of the metamaterial.

62 citations

Journal ArticleDOI
TL;DR: In this paper, a microstrip-fed patch antenna for cell phone applications is proposed, which has an impedance bandwidth of 230.4 MHz (0.725-0.95 GHz, lower band) and 522.24 MHz (1.74-2.25 GHz, upper band).
Abstract: The aim of this study is to design a new microstrip-fed patch antenna for cell phone applications. The antenna design is composed of slots and Flame Retardant 4 dielectric substrate fed by a partial ground plane and a microstrip line. The user's effects on antenna performances are also analysed using standard specific anthropomorphic mannequin head phantom. The specific absorption rate (SAR) values of the proposed antenna are evaluated for different frequency bands considering cheek position of talk mode. The proposed antenna has an impedance bandwidth of 230.4 MHz (0.725-0.95 GHz, lower band), and 522.24 MHz (1.74-2.25 GHz, upper band), which can cover global system for mobile (GSM) 900 MHz, digital communication system 1800 MHz, personal communications service 1900 MHz, GSM 1900 MHz, and universal mobile telecommunications service 2100 MHz bands. Moreover, the proposed antenna produces lower SAR values in the human head than that of a dipole antenna, helical antenna, and planar inverted-F antenna.

29 citations

Journal ArticleDOI
TL;DR: In this article, the effects of antenna substrate materials on electromagnetic (EM) absorption in a human head were analyzed with four different dielectric substrate materials, which are Bakelite, FR4 glass epoxy, Rogers R04003, and Taconic TLC.
Abstract: Cellular phones are used in the vicinity of a human head, which absorbs power from antenna radiation. This investigation analyzes the effects of antenna substrate materials on electromagnetic (EM) absorption in a human head. Antennas are used in analysis with four different dielectric substrate materials, which are Bakelite, FR4 glass epoxy, Rogers R04003, and Taconic TLC. Moreover, two different thicknesses of each substrate are considered in the experimental setup. The EM absorption associated with two types of cell phone antennas is evaluated in the closed vicinity of the human head model. One of them is planar inverted-F antenna (PIFA), which is used as the internal handset antenna and another one is helical antenna, which is used as external handset antenna. This investigation consists of two different operating frequency bands, GSM 900 MHz and DCS 1800 MHz. The EM absorption in the human head is presented using the peak specific absorption rate (SAR) and total absorbed power (TAP) by the user. The finite-difference time-domain (FDTD) method based on Computer Simulation Technology (CST) Microwave studio is utilized in this investigation. The obtained results show that the substrate materials do not effect SAR and TAP values considerably for both antennas, but substrate thickness affects the SAR and TAP values significantly. In addition, the substrate thickness affects the SAR and TAP values significantly in most of the cases Moreover, PIFA produces lower SAR than that of a helical antenna significantly for both GSM and DCS frequency band. DOI: http://dx.doi.org/10.5755/j01.ms.22.3.8889

2 citations

Peer Review
TL;DR: Amongst the various modalities suggested in the literature, the RCU reconstruction with distraction osteogenesis and costochondral grafting provide best result functionally and aesthetically.
Abstract: Introduction: Comprehensive management of TMJ ankylosis including restoration of form, function and aesthetics is a challenging aspect for Oral & Maxillofacial Surgeon. Various treatment modalities have been reported in the literature with their merits, demerits and diverse success rate. Materials and Method: We report our experience in reconstruction of Ramal Condylar Unit (RCU) in temporomandibular joint ankylosis patients in a retrospective review. A total of 06 cases of TMJ ankylosis were included in the review. The cases were managed in our tertiary care centre from June 2019 to June 2020. Demographic distribution of the patients, preoperative findings, surgical modalities used for RCU reconstruction and postoperative outcome were recorded and compared. Results: Average mouth opening increased from 8.5 mm pre-operatively to 29.5 mm 3 months postoperatively. 02 cases of Sawhney’s type I and II ankylosis were managed by interpositional gap arthroplasty using temporalis myofascial flap. 01 case of Sawhney’s type I ankylosis was managed by gap arthroplasty interposed with dermis-fat graft. 02 cases of Sawhney’s type III ankylosis were managed by osteoarthrectomy and reconstruction of RCU by costochondral graft. In 01 case with Sawhney’s type III ankylosis, functional joint was reconstructed using distraction osteogenesis. We encountered 01 case of recurrence in a case managed by costochondral grafting. Conclusion: Amongst the various modalities suggested in the literature, the RCU reconstruction with distraction osteogenesis and costochondral grafting provide best result functionally and aesthetically. The diagnosis, timely management and post-operative follow up are the key to success in TMJ ankylosis.
Journal ArticleDOI
TL;DR: The obtained results indicate that the printed monopole antenna lead to higher EM absorption in the human head as compared to PIFA for both GSM frequencies.
Abstract: This paper represents a comparative study on electromagnetic (EM) absorption in the human head between a printed monopole antenna and a planar inverted-F antenna (PIFA). The specific absorption rate (SAR) values and total absorbed power in the human head phantom are used to evaluate EM absorption for both antennae. Moreover, antenna performances in terms of return loss, radiation efficiency, and gain are also investigated in this study. The finite integration technique (FIT) based on CST Microwave studio and SAM head phantom are used in this study. The antenna performances are measured in an anechoic chamber and the SAR is tested using COMOSAR measurement system. The obtained results indicate that the printed monopole antenna lead to higher EM absorption in the human head as compared to PIFA for both GSM frequencies.

Cited by
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Journal ArticleDOI
TL;DR: In this article, a dual-band, low profile, high gain, and low specific absorption rate (SAR) triangular slotted monopole antenna with a $4\times 4$ artificial magnetic conductor (AMC) array is presented for WBAN applications.
Abstract: A dual-band, low profile, high gain, and low specific absorption rate (SAR) triangular slotted monopole antenna backed with a $4\times 4$ artificial magnetic conductor (AMC) array is presented for wireless body area network (WBAN) applications. The antenna is printed on a Rogers ULTRALAM 3850 substrate, whereas the AMC array is printed on a RO3003 substrate. The design operates at 3.5 GHz, for WiMAX wireless applications, and at 5.8 GHz for the ISM Band. The proposed antenna preserved the dual-band resonance and exhibited acceptable gain and SAR at a separation of 15 mm from the human body model. To reduce such separation and achieve enhancements to gain and SAR, an AMC array was utilized. In free space, gain enhancements by 6.8 and 3.7 dBi were achieved at both frequencies, respectively. Furthermore, over a gap of 1 mm from the human body, gain enhancements by 23.3 and 13.9 dBi were achieved at both frequencies, respectively. In addition, SAR reductions by almost 99% were attained. The antenna was fabricated and measured where a very good agreement was observed between simulated and measured results, with and without the incorporated AMC array. With such results, the proposed design can be highly recommended for wearable medical applications, specifically for diabetic patients.

101 citations

Journal ArticleDOI
TL;DR: A compact double-negative (DNG) metamaterial that exhibits a negative refractive index (NRI) bandwidth of more than 3.6 GHz considering the frequency from 2 to 14 GHz is introduced.
Abstract: The aim of this paper is to introduce a compact double-negative (DNG) metamaterial that exhibits a negative refractive index (NRI) bandwidth of more than 3.6 GHz considering the frequency from 2 to 14 GHz. In this framework, two arms of the designed unit cell are split in a way that forms a Modified-Z-shape structure of the FR-4 substrate material. The finite integration technique (FIT)-based Computer Simulation Technology (CST) Microwave Studio is applied for computation, and the experimental setup for measuring the performance is performed inside two waveguide ports. Therefore, the measured data complies well with the simulated data of the unit cell at 0-degree and 90-degree rotation angles. The designed unit cell shows a negative refractive index from 3.482 to 7.096 GHz (bandwidth of 3.61 GHz), 7.876 to 10.047 GHz (bandwidth of 2.171 GHz), and 11.594 to 14 GHz (bandwidth of 2.406 GHz) in the microwave spectra. The design also exhibits almost the same wide negative refractive index bandwidth in the major region of the C-band and X-band if it is rotated 90 degrees. However, the novelty of the proposed structure lies in its effective medium ratio of more than 4, wide bandwidth, and compact size.

83 citations

Journal ArticleDOI
TL;DR: In this paper, a horizontally inverse double L-shaped metamaterial with a square split ring resonator on the outer side was etched on a Rogers RT5880 dielectric substrate material.
Abstract: The principle purpose of this study was to produce a horizontally inverse double L-shaped metamaterial that was applicable for triple-band applications and that exhibited negative permittivity and permeability in the resonance frequencies. The horizontally inverse double L-shaped structure had a square split ring resonator on the outer side that was etched on a Rogers RT5880 dielectric substrate material. The size of the unit cell was 10 × 10 mm2. The CST Microwave Studio electromagnetic simulator was utilized for the design and analysis of the proposed metamaterial. Analyses and comparisons were performed with different configurations, such as the use of different substrates, varying the width of the splits, and the use of different array arrangements. All the arrangements confirmed that triple-band operation frequency lay in the C-, X-, and Ku-bands. The double negative and negative refractive index regions as seen in the unit cell results and the array results harmonized between 6–7.632 GHz, 7.932–8.388 GHz, 9.204–9.804 GHz, 10.284–13.356 GHz, 13.716–16.632 GHz, 16.872–17.136 GHz, 17.52–17.652 GHz and 10.692–12.828 GHz, 13.02–13.5 GHz, 14.928–18 GHz, respectively. The scattering parameters dimensions of the introduced horizontally inverse double L-structured metamaterial is favorable for different applications associated with C-, X-, and Ku-bands such as long-distance, military, and satellite communications.

46 citations

Journal ArticleDOI
TL;DR: In this article, a design of Microstrip Patch Antenna (MPA) using hybrid fractal slot (Koch-Minkowski and Koch-Koch) along with partial ground plane for wideband applications is presented.

45 citations

Journal ArticleDOI
TL;DR: A microstrip patch antenna array, inspired with a superstrate – comprising of Split Ring Resonators (SRR) and wire strips, designed and discussed, which provides the gain improvement of 7.8 dBi and bandwidth enhancement of 355 MHz.
Abstract: Though a microstrip patch antenna has advantages of low profile and structural planarity, but a single microstrip patch antenna has limitation of low gain and narrow bandwidth To overcome these problems, multi-layer structures are used The antenna performance can further be enhanced, if multi-layer structures are designed for array of patch antennas Moreover, the simultaneous improvement of gain and bandwidth, which are two conflicting parameters, is another challenge To meet these challenges, this article proposes a microstrip patch antenna array, inspired with a superstrate – comprising of Split Ring Resonators (SRR) and wire strips Gain and bandwidth of 43 dBi and 425 MHz, respectively, is achieved by an unloaded array at IEEE 80216a 58 GHz Wi-MAX band However, by covering this array with the proposed superstrate, gain and bandwidth of 121 dBi and 780 MHz, respectively, is obtained, thus providing the gain improvement of 78 dBi and bandwidth enhancement of 355 MHz Fabrication and testing of the proposed antenna is done for comparing simulated and measured results Equivalent circuit of this newly devised array has been designed and discussed

40 citations