Design and Analysis of a Compact GSM/GPS Dual-Band Bandpass Filter Using a T-Shaped Resonator

Basit Abdul,Khattak Muhammad Irfan,Al-Hasan Mauth,Nebhen Jamel,Jan Atif 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.2

This study presents an ultracompact dual-band bandpass filter with controllable transmission zeros based on quarter-wave dual-mode resonator for GSM (global system for mobile communications) and GPS (global positioning system) wireless applications. The filter is made up of two quarter-wave resonators, which help to independently control the passbands. A direct feed resonator creates the first operating band, which serves as a feeding source for the interior resonator and operates at a higher frequency band. Therefore, a pair of transmission zeros can be energized between the two passbands, and high roll-off skirts are obtained. To reduce the size of the entire filter, the two resonators are bent and connected together through a hole in a metal base. The structure is symmetrical in nature, so both frequency bands can be obtained using the even-odd mode analysis method. For GSM applications, the center frequency of the first working band is 850 MHz, while for GPS wireless applications, the center frequency of the second working band is 1.57 GHz. Although there is a feed line (λg is based on a waveguide length of 850 MHz), the filter has been simulated and fabricated for verification, with an ultra-compact size of 0.10 λg × 0.09 λg (0.0095 λg 2). The simulation results and measured results match well, and the theory of the design concept is recognized.

Compact Tri-band Bandpass Filter Based on Asymmetric Step Impedance Resonators for WiMAX and RFID Systems

Abdul Basit,Muhammad Irfan Khattak,Ayman Althuwayb,Jamel Nebhen 한국전자파학회JEES 2021 Journal of Electromagnetic Engineering and Science Vol.21 No.4

In this article, a simple method is developed to design a highly miniaturized tri-band bandpass filter (BPF) utilizing two asymmetric coupled resonators with one step discontinuity and one uniform impedance resonator (UIR) for worldwide interoperability for microwave access (WiMAX) and radio frequency identification (RFID) applications. The first and second passbands located at 3.7 GHz and 6.6 GHz are achieved through two asymmetric coupled step impedance resonators (SIRs), while the third passband, centered at 9 GHz, is achieved using a half-wavelength UIR, respectively. The fundamental frequencies of this BPF are implemented by tuning the physical length ratio (α) and impedance ratio (R) of the asymmetric SIRs. The proposed filter is designed and fabricated with a circuit dimension of 13.69 mm × 25 mm (0.02 λg × 0.03 λg), where λg represents the guided wavelength at the first passband. The experimental and measured results are provided with good matching.

Rehabilitation of reinforced concrete frames with non-seismic details using eccentric steel braces

Abdul Basit,Muhammad S. Khan,Naveed Ahmad 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.80 No.4

This paper presents quasi-static cyclic loading tests of reduced scale reinforced concrete Eccentrically Steel Brace (ESB) retrofitted and bare portal frames. A hollow square steel brace was attached to the beam diagonally at a distance of LBeam/8 from the beam ends for enhancing the seismic performance of deficient frames. Results indicated promising behavior of ESB retrofitted frame opposed to the bare frames and shifted the damage mechanism from severe shear cracking and column flexural hinging to beam flexural cracking. ESB retrofitted frame also increased lateral force-displacement capacity, stiffness and hysteretic damping compared to the bare frames. The test results were also used to calibrate a nonlinear modeling technique proposed using a finite element based program. Additionally, a nonlinear dynamic acceleration time history analysis were carried out for two-story ESB retrofitted and bare frames and inter-story drift limits were identified for each structure. The study also confirms the importance of joint detailing’s and its beneficial role in improving the seismic performance of frames under earthquake ground motions.

Efficacy of In₂S₃ interfacial recombination barrier layer in PbS quantum-dot-sensitized solar cells

Basit, Muhammad Abdul,Abbas, Muhammad Awais,Bang, Jin Ho,Park, Tae Joo Elsevier 2015 JOURNAL OF ALLOYS AND COMPOUNDS Vol.653 No.-

<P><B>Abstract</B></P> <P>In<SUB>2</SUB>S<SUB>3</SUB> interfacial recombination barrier layer (IBL) via successive ionic layer adsorption and reaction (SILAR) was successfully employed between PbS quantum dots and mesoporous TiO<SUB>2</SUB> in quantum-dot-sensitized solar cells (QDSSCs). In<SUB>2</SUB>S<SUB>3</SUB> IBL significantly increased the resistance against back electron transfer from TiO<SUB>2</SUB>, resulting an increment in the photocurrent density (<I>J</I> <SUB> <I>SC</I> </SUB>) for the cell with single SILAR cycle of In<SUB>2</SUB>S<SUB>3</SUB> IBL. Further increase in the number of SILAR cycles of In<SUB>2</SUB>S<SUB>3</SUB> IBL deteriorated the <I>J</I> <SUB> <I>SC</I> </SUB>, whereas open-circuit voltage sustained the increasing trend. Therefore, an optimal photo-conversion efficiency of ∼2.2% was obtained for the cell with 2 SILAR cycles of In<SUB>2</SUB>S<SUB>3</SUB> IBL, which strategically reached a value of ∼2.70% after annealing (increased by 40% compared to the control cell without IBL). In<SUB>2</SUB>S<SUB>3</SUB> IBL not only improved the recombination resistance and electron life time of the cells, but it also enhanced the photostability of the cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> In<SUB>2</SUB>S<SUB>3</SUB> interfacial recombination barrier layer was deposited on TiO<SUB>2</SUB> photoanode via SILAR process. </LI> <LI> Resistance against back electron transfer from TiO<SUB>2</SUB> (recombination) increased notably. </LI> <LI> Fabricated PbS-QDSSCs were characterized using IPCE, OCVD and EIS techniques. </LI> <LI> In<SUB>2</SUB>S<SUB>3</SUB> IBL improved chemical capacitance, electron life time and photostability of modified cells. </LI> <LI> 2In<SUB>2</SUB>S<SUB>3</SUB> IBL showed optimal performance, yielding 40% improvement in PCE after heat treatment. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Analysis of Coupling Effect in Holey Fiber

Abdul Basit,Engr Faizullah,Basit Hassan 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

This paper describes the analysis of coupling effect in Holey Fiber (HF), a recent innovation in the field of optical wave guiding. HF is an all-silica optical fiber with a solid core surrounded by an array of air holes that provide a low-index cladding. The strong guidance of HF and the numerous degrees of freedom available in design give rise to novel properties, including the capability of single mode behavior over an unprecedented range of wavelengths, and anomalous dispersion below 1.27 μm. The Finite Difference Time Domain (FDTD) method was used to develop a new model for the study of Holey Fiber (HF). Results obtained from this model correlated well with existing experimental and analytic results. The model was applied to analyze coupling effects in HF.

Investigation of single bubble behavior under rolling motions using multiphase MPS method on GPU

Basit, Muhammad Abdul,Tian, Wenxi,Chen, Ronghua,Basit, Romana,Qiu, Suizheng,Su, Guanghui Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.6

Study of single bubble behavior under rolling motions can prove useful for fundamental understanding of flow field inside the modern small modular nuclear reactors. The objective of the present study is to simulate the influence of rolling conditions on single rising bubble in a liquid using multiphase Moving Particle Semi-implicit (MPS) method. Rolling force term was added to 2D Navier-Stokes equations and a computer program was written using C language employing OpenACC to port the code to GPU. Computational results obtained were found to be in good agreement with the results available in literature. The impact of rolling parameters on trajectory and velocity of the rising bubble has been studied. It has been found that bubble rise velocity increases with rolling amplitude due to modification of flow field around the bubble. It has also been concluded that the oscillations of free surface, caused by rolling, influence the bubble trajectory. Furthermore, it has been discovered that smaller vessel width reduces the impact of rolling motions on the rising bubble. The effect of liquid viscosity on bubble rising under rolling was also investigated and it was found that effects of rolling became more pronounced with the increase of liquid viscosity.

SOC Estimation of Flooded Lead Acid Battery Using an Adaptive Unscented Kalman Filter

Abdul Basit Khan(압둘바싯칸),Woojin Choi(최우진) 전력전자학회 2016 전력전자학술대회 논문집 Vol.2016 No.11

The cGAS/STING/TBK1/IRF3 innate immunity pathway maintains chromosomal stability through regulation of p21 levels

Abdul Basit,조민국,Eui-Yun Kim,Dohyeong Kwon,Suk-Jo Kang,Jae-Ho Lee 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

Chromosomal instability (CIN) in cancer cells has been reported to activate the cGAS–STING innate immunity pathway via micronuclei formation, thus affecting tumor immunity and tumor progression. However, adverse effects of the cGAS/STING pathway as they relate to CIN have not yet been investigated. We addressed this issue using knockdown and add-back approaches to analyze each component of the cGAS/STING/TBK1/IRF3 pathway, and we monitored the extent of CIN by measuring micronuclei formation after release from nocodazole-induced mitotic arrest. Interestingly, knockdown of cGAS (cyclic GMP-AMP synthase) along with induction of mitotic arrest in HeLa and U2OS cancer cells clearly resulted in increased micronuclei formation and chromosome missegregation. Knockdown of STING (stimulator of interferon genes), TBK1 (TANK-binding kinase-1), or IRF3 (interferon regulatory factor-3) also resulted in increased micronuclei formation. Moreover, transfection with cGAMP, the product of cGAS enzymatic activity, as well as addback of cGAS WT (but not catalytic-dead mutant cGAS), or WT or constitutively active STING (but not an inactive STING mutant) rescued the micronuclei phenotype, demonstrating that all components of the cGAS/STING/TBK1/IRF3 pathway play a role in preventing CIN. Moreover, p21 levels were decreased in cGAS-, STING-, TBK1-, and IRF3knockdown cells, which was accompanied by the precocious G2/M transition of cells and the enhanced micronuclei phenotype. Overexpression of p21 or inhibition of CDK1 in cGAS-depleted cells reduced micronuclei formation and abrogated the precocious G2/M transition, indicating that the decrease in p21 and the subsequent precocious G2/M transition is the main mechanism underlying the induction of CIN through disruption of cGAS/STING signaling.

Improved light absorbance and quantum-dot loading by macroporous TiO₂ photoanode for PbS quantum-dot-sensitized solar cells

Basit, Muhammad Abdul,Abbas, Muhammad Awais,Jung, Eun Sun,Bang, Jin Ho,Park, Tae Joo Elsevier Sequoia S.A 2017 Materials chemistry and physics Vol.196 No.-

<P><B>Abstract</B></P> <P>Macroporous titanium dioxide (TiO<SUB>2</SUB>) layer was formed through selective etching of silica (SiO<SUB>2</SUB>) microspheres incorporated in TiO<SUB>2</SUB>/SiO<SUB>2</SUB> composite layer, resulting in a significant increase in the photovoltaic performance of PbS quantum-dot-sensitized solar cells (QDSSCs). Strategic incorporation of macroporous TiO<SUB>2</SUB> layer on top of a mesoporous layer improved the light absorption characteristics, which is concurrently attributed to light scattering behaviour of macropores and increased loading of quantum dots (QDs) <I>via</I> successive ionic layer adsorption and reaction process. Thereby, a direct increase in the photocurrent density of PbS-QDSSC was ensued. Open-circuit voltage decay analysis combined with in-depth electrochemical impedance spectroscopy revealed a significant improvement in the electron life time and recombination resistance of QDSSC which was credited to the barrier effect of more uniformly loaded PbS QDs inside macroporous TiO<SUB>2</SUB> photoanode.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Macroporous TiO<SUB>2</SUB> photoanode was developed using HF-etching of SiO<SUB>2</SUB> microspheres. </LI> <LI> Macroporous TiO<SUB>2</SUB> layer enhanced light scattering characteristics of photoanode. </LI> <LI> QD loading was enhanced due to better diffusion of ionic precursors in photoanode. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Enhanced PbS quantum dot loading on TiO₂ photoanode using atomic-layer-deposited ZnS interfacial layer for quantum dot-sensitized solar cells

Basit, Muhammad Abdul,Abbas, Muhammad Awais,Jung, Eun Sun,Ali, Ijaz,Kim, Dae Woong,Bang, Jin Ho,Joo Park, Tae Elsevier 2018 Materials chemistry and physics Vol.220 No.-

<P><B>Abstract</B></P> <P>Ultrathin and conformal ZnS film grown by atomic layer deposition was employed in quantum dot-sensitized solar cells (QDSSCs) as an interfacial layer (IL) between mesoporous TiO<SUB>2</SUB> photoanode and successive ionic layer adsorption and reaction (SILAR)-grown PbS QDs. ZnS IL provided more nucleation sites compared to a bare TiO<SUB>2</SUB> photoanode, which enhanced PbS QDs loading remarkably. As a result, the optical absorbance and thus photocurrent density considerably increased. The power conversion efficiency of QDSSCs increased from 3.4% to 4% by introducing the ZnS IL. However, the <I>β</I>-recombination model obtained from electrochemical impedance spectroscopy revealed the evolution of charge carrier recombination inside QDs as a consequence of enhanced QD loading, which partly dilutes this benefit.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ultrathin and conformal ZnS interfacial layer (IL) was grown on mesoporous TiO<SUB>2</SUB> photoanode by atomic layer deposition. </LI> <LI> ZnS IL provided more nucleation sites for PbS QDs deposition using SILAR. </LI> <LI> Light absorbance, photocurrent density and power conversion efficiency of QDSSCs were increased by adoption of ZnS IL. </LI> </UL> </P>