Displaying publications 41 - 60 of 66 in total

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  1. Axial contraction in etched optical fiber due to internal stress reduction
    Lim KS, Yang HZ, Chong WY, Cheong YK, Lim CH, Ali NM, et al.
    Opt Express, 2013 Feb 11;21(3):2551-62.
    PMID: 23481713 DOI: 10.1364/OE.21.002551
    When an optical fiber is dipped in an etching solution, the internal stress profile in the fiber varies with the fiber diameter. We observed a physical contraction as much as 0.2% in the fiber axial dimension when the fiber was reduced from its original diameter to ~6 µm through analysis using high resolution microscope images of the grating period of an etched FBG at different fiber diameters. This axial contraction is related to the varying axial stress profile in the fiber when the fiber diameter is reduced. On top of that, the refractive index of fiber core increases with reducing fiber diameter due to stress-optic effect. The calculated index increment is as much as 1.8 × 10(-3) at the center of fiber core after the diameter is reduced down to ~6 µm. In comparison with the conventional model that assumes constant grating period and neglects the variation in stress-induced index change in fiber core, our proposed model indicates a discrepancy as much as 3nm in Bragg wavelength at a fiber diameter of ~6 µm.
    Matched MeSH terms: Computer-Aided Design
  2. Synthesis, enzyme inhibition and molecular docking studies of 1-Arylsulfonyl-4-phenylpiperazine derivatives
    Abbasi MA, Anwar A, Rehman A, Siddiqui SZ, Rubab K, Shah SAA, et al.
    Pak J Pharm Sci, 2017 Sep;30(5):1715-1724.
    PMID: 29084694
    Heterocyclic molecules have been frequently investigated to possess various biological activities during the last few decades. The present work elaborates the synthesis and enzymatic inhibition potentials of a series of sulfonamides. A series of 1-arylsulfonyl-4-Phenylpiperazine (3a-n) geared up by the reaction of 1-phenylpiperazine (1) and different (un)substituted alkyl/arylsulfonyl chlorides (2a-n), under defined pH control using water as a reaction medium. The synthesized molecules were characterized by 1H-NMR, 13C-NMR, IR and EI-MS spectral data. The enzyme inhibition study was carried on α-glucosidase, lipoxygenase (LOX), acetyl cholinesterase (AChE) and butyryl cholinesterase (BChE) enzymes supported by docking simulation studies and the IC50 values rendered a few of the synthesized molecules as moderate inhibitors of these enzymes where, the compound 3e exhibited comparatively better potency against α-glucosidase enzyme. The synthesized compounds showed weak or no inhibition against LOX, AChE and BChE enzymes.
    Matched MeSH terms: Computer-Aided Design*
  3. Fulltext Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing
    Asadi-Eydivand M, Solati-Hashjin M, Shafiei SS, Mohammadi S, Hafezi M, Abu Osman NA
    PLoS One, 2016;11(3):e0151216.
    PMID: 26999789 DOI: 10.1371/journal.pone.0151216
    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C-1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C-1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds were observed in this study, the mechanical properties were not significantly improved, requiring further investigations. However, the findings of this study give a better insight into the complex nature of the problem in the fabrication of synthetic bone grafts and scaffolds via post-fabrication treatment of 3DP calcium sulfate prototypes.
    Matched MeSH terms: Computer-Aided Design
  4. Fulltext Shape Optimization for Additive Manufacturing of Removable Partial Dentures--A New Paradigm for Prosthetic CAD/CAM
    Chen J, Ahmad R, Suenaga H, Li W, Sasaki K, Swain M, et al.
    PLoS One, 2015;10(7):e0132552.
    PMID: 26161878 DOI: 10.1371/journal.pone.0132552
    With ever-growing aging population and demand for denture treatments, pressure-induced mucosa lesion and residual ridge resorption remain main sources of clinical complications. Conventional denture design and fabrication are challenged for its labor and experience intensity, urgently necessitating an automatic procedure. This study aims to develop a fully automatic procedure enabling shape optimization and additive manufacturing of removable partial dentures (RPD), to maximize the uniformity of contact pressure distribution on the mucosa, thereby reducing associated clinical complications. A 3D heterogeneous finite element (FE) model was constructed from CT scan, and the critical tissue of mucosa was modeled as a hyperelastic material from in vivo clinical data. A contact shape optimization algorithm was developed based on the bi-directional evolutionary structural optimization (BESO) technique. Both initial and optimized dentures were prototyped by 3D printing technology and evaluated with in vitro tests. Through the optimization, the peak contact pressure was reduced by 70%, and the uniformity was improved by 63%. In vitro tests verified the effectiveness of this procedure, and the hydrostatic pressure induced in the mucosa is well below clinical pressure-pain thresholds (PPT), potentially lessening risk of residual ridge resorption. This proposed computational optimization and additive fabrication procedure provides a novel method for fast denture design and adjustment at low cost, with quantitative guidelines and computer aided design and manufacturing (CAD/CAM) for a specific patient. The integration of digitalized modeling, computational optimization, and free-form fabrication enables more efficient clinical adaptation. The customized optimal denture design is expected to minimize pain/discomfort and potentially reduce long-term residual ridge resorption.
    Matched MeSH terms: Computer-Aided Design*
  5. Fulltext Optimal placement of unified power flow controllers to improve dynamic voltage stability using power system variable based voltage stability indices
    Albatsh FM, Ahmad S, Mekhilef S, Mokhlis H, Hassan MA
    PLoS One, 2015;10(4):e0123802.
    PMID: 25874560 DOI: 10.1371/journal.pone.0123802
    This study examines a new approach to selecting the locations of unified power flow controllers (UPFCs) in power system networks based on a dynamic analysis of voltage stability. Power system voltage stability indices (VSIs) including the line stability index (LQP), the voltage collapse proximity indicator (VCPI), and the line stability index (Lmn) are employed to identify the most suitable locations in the system for UPFCs. In this study, the locations of the UPFCs are identified by dynamically varying the loads across all of the load buses to represent actual power system conditions. Simulations were conducted in a power system computer-aided design (PSCAD) software using the IEEE 14-bus and 39- bus benchmark power system models. The simulation results demonstrate the effectiveness of the proposed method. When the UPFCs are placed in the locations obtained with the new approach, the voltage stability improves. A comparison of the steady-state VSIs resulting from the UPFCs placed in the locations obtained with the new approach and with particle swarm optimization (PSO) and differential evolution (DE), which are static methods, is presented. In all cases, the UPFC locations given by the proposed approach result in better voltage stability than those obtained with the other approaches.
    Matched MeSH terms: Computer-Aided Design
  6. Design of new generation femoral prostheses using functionally graded materials: a finite element analysis
    Oshkour AA, Abu Osman NA, Yau YH, Tarlochan F, Abas WA
    Proc Inst Mech Eng H, 2013 Jan;227(1):3-17.
    PMID: 23516951
    This study aimed to develop a three-dimensional finite element model of a functionally graded femoral prosthesis. The model consisted of a femoral prosthesis created from functionally graded materials (FGMs), cement, and femur. The hip prosthesis was composed of FGMs made of titanium alloy, chrome-cobalt, and hydroxyapatite at volume fraction gradient exponents of 0, 1, and 5, respectively. The stress was measured on the femoral prosthesis, cement, and femur. Stress on the neck of the femoral prosthesis was not sensitive to the properties of the constituent material. However, stress on the stem and cement decreased proportionally as the volume fraction gradient exponent of the FGM increased. Meanwhile, stress became uniform on the cement mantle layer. In addition, stress on the femur in the proximal part increased and a high surface area of the femoral part was involved in absorbing the stress. As such, the stress-shielding area decreased. The results obtained in this study are significant in the design and longevity of new prosthetic devices because FGMs offer the potential to achieve stress distribution that more closely resembles that of the natural bone in the femur.
    Matched MeSH terms: Computer-Aided Design
  7. A review of history of CAD/CAM system application in the production of transtibial prosthetic socket in developing countries (from 1980 to 2019)
    Afiqah Hamzah N, Razak NAA, Sayuti Ab Karim M, Gholizadeh H
    Proc Inst Mech Eng H, 2021 Dec;235(12):1359-1374.
    PMID: 34304625 DOI: 10.1177/09544119211035200
    The development of the CAD/CAM (Computer-aided design and computer-aided manufacturing) system has globally changed the fabrication and delivery of prosthetics and orthotics. Furthermore, since the introduction of CAD/CAM in the 1980s, many successful CAD/CAM system are available in the market today. However, less than 20% of amputees have access to digital fabrication technology and large portion of the amputees are from the developing countries. This review designed to examine selected studies from 1980 to 2019 on CAD/CAM systems in the production of transtibial prosthetic sockets. A review was conducted based on articles gathered from Web of Science, Pubmed and Science Direct. From the findings, 92 articles found related to CAD/CAM-derived transtibial prosthetic socket (TPS). After a further screening of the articles, 20 studies were chosen and only one study was done in a developing country. The results showed an increase interest in CAD/CAM application in Transtibial prosthetic socket (TPS) production for both developed and developing countries, yet the technology has not fully utilised in the developing countries. Factors such as resources, accessibility, knowledge-gap and lack of experienced prosthetists remain the major causes of the lack of CAD/CAM system studies. Large-scale trials are required to employ digital fabrication in the developing regions, consequently advancing the production of high-quality CAD-CAM-derived TPS where most prosthetic and orthotics are needed.
    Matched MeSH terms: Computer-Aided Design
  8. Low energy, low latency and high speed array divider circuit using a shannon theorem based adder cell
    Senthilpari C, Diwakar K, Singh AK
    Recent Pat Nanotechnol, 2009;3(1):61-72.
    PMID: 19149756
    The paper discuss the design of 1-bit full adder circuit using Shannon theorem. This proposed full adder circuit is used as one of the circuit component for implementation of Non- Restoring and Restoring divider circuits. The proposed adder and divider schematics are designed by using DSCH2 CAD tool and their layouts are generated by Microwind 3 VLSI CAD tool. The divider circuits are designed by using standard CMOS 0.35 microm feature size and corresponding power supply 3.5 V. The parameters analyses are carried out by BSIM 4 analysis. We have compared the simulated results of the Shannon based divider circuit with CPL and CMOS adder cell based divider circuits. We have further compared the results with published results and observed that the proposed adder cell based divider circuit dissipates lower power, gives faster response, lower latency, low EPI and high throughput.
    Matched MeSH terms: Computer-Aided Design*
  9. Fulltext Development and virtual validation of a novel digital workflow to rehabilitate palatal defects by using smartphone-integrated stereophotogrammetry (SPINS)
    Farook TH, Jamayet NB, Asif JA, Din AS, Mahyuddin MN, Alam MK
    Sci Rep, 2021 04 19;11(1):8469.
    PMID: 33875672 DOI: 10.1038/s41598-021-87240-9
    Palatal defects are rehabilitated by fabricating maxillofacial prostheses called obturators. The treatment incorporates taking deviously unpredictable impressions to facsimile the palatal defects into plaster casts for obturator fabrication in the dental laboratory. The casts are then digitally stored using expensive hardware to prevent physical damage or data loss and, when required, future obturators are digitally designed, and 3D printed. Our objective was to construct and validate an economic in-house smartphone-integrated stereophotogrammetry (SPINS) 3D scanner and to evaluate its accuracy in designing prosthetics using open source/free (OS/F) digital pipeline. Palatal defect models were scanned using SPINS and its accuracy was compared against the standard laser scanner for virtual area and volumetric parameters. SPINS derived 3D models were then used to design obturators by using (OS/F) software. The resultant obturators were virtually compared against standard medical software designs. There were no significant differences in any of the virtual parameters when evaluating the accuracy of both SPINS, as well as OS/F derived obturators. However, limitations in the design process resulted in minimal dissimilarities. With further improvements, SPINS based prosthetic rehabilitation could create a viable, low cost method for rural and developing health services to embrace maxillofacial record keeping and digitised prosthetic rehabilitation.
    Matched MeSH terms: Computer-Aided Design
  10. Fulltext Computer-aided design and 3-dimensional artificial/convolutional neural network for digital partial dental crown synthesis and validation
    Farook TH, Ahmed S, Jamayet NB, Rashid F, Barman A, Sidhu P, et al.
    Sci Rep, 2023 Jan 28;13(1):1561.
    PMID: 36709380 DOI: 10.1038/s41598-023-28442-1
    The current multiphase, invitro study developed and validated a 3-dimensional convolutional neural network (3D-CNN) to generate partial dental crowns (PDC) for use in restorative dentistry. The effectiveness of desktop laser and intraoral scanners in generating data for the purpose of 3D-CNN was first evaluated (phase 1). There were no significant differences in surface area [t-stat(df) = - 0.01 (10), mean difference = - 0.058, P > 0.99] and volume [t-stat(df) = 0.357(10)]. However, the intraoral scans were chosen for phase 2 as they produced a greater level of volumetric details (343.83 ± 43.52 mm3) compared to desktop laser scanning (322.70 ± 40.15 mm3). In phase 2, 120 tooth preparations were digitally synthesized from intraoral scans, and two clinicians designed the respective PDCs using computer-aided design (CAD) workflows on a personal computer setup. Statistical comparison by 3-factor ANOVA demonstrated significant differences in surface area (P 
    Matched MeSH terms: Computer-Aided Design*
  11. Fulltext Analysis and optimization of spiral circular inductive coupling link for bio-implanted applications on air and within human tissue
    Mutashar S, Hannan MA, Samad SA, Hussain A
    Sensors (Basel), 2014;14(7):11522-41.
    PMID: 24984057 DOI: 10.3390/s140711522
    The use of wireless communication using inductive links to transfer data and power to implantable microsystems to stimulate and monitor nerves and muscles is increasing. This paper deals with the development of the theoretical analysis and optimization of an inductive link based on coupling and on spiral circular coil geometry. The coil dimensions offer 22 mm of mutual distance in air. However, at 6 mm of distance, the coils offer a power transmission efficiency of 80% in the optimum case and 73% in the worst case via low input impedance, whereas, transmission efficiency is 45% and 32%, respectively, via high input impedance. The simulations were performed in air and with two types of simulated human biological tissues such as dry and wet-skin using a depth of 6 mm. The performance results expound that the combined magnitude of the electric field components surrounding the external coil is approximately 98% of that in air, and for an internal coil, it is approximately 50%, respectively. It can be seen that the gain surrounding coils is almost constant and confirms the omnidirectional pattern associated with such loop antennas which reduces the effect of non-alignment between the two coils. The results also show that the specific absorption rate (SAR) and power loss within the tissue are lower than that of the standard level. Thus, the tissue will not be damaged anymore.
    Matched MeSH terms: Computer-Aided Design*
  12. Fulltext G3 assisted rational design of chemical sensor array using carbonitrile neutral receptors
    Rosli AN, Bakar MA, Manan NS, Woi PM, Lee VS, Zain SM, et al.
    Sensors (Basel), 2013;13(10):13835-60.
    PMID: 24129020 DOI: 10.3390/s131013835
    Combined computational and experimental strategies for the systematic design of chemical sensor arrays using carbonitrile neutral receptors are presented. Binding energies of acetonitrile, n-pentylcarbonitrile and malononitrile with Ca(II), Mg(II), Be(II) and H⁺ have been investigated with the B3LYP, G3, CBS-QB3, G4 and MQZVP methods, showing a general trend H⁺ > Be(II) > Mg(II) > Ca(II). Hydrogen bonding, donor-acceptor and cation-lone pair electron simple models were employed in evaluating the performance of computational methods. Mg(II) is bound to acetonitrile in water by 12.5 kcal/mol, and in the gas phase the receptor is more strongly bound by 33.3 kcal/mol to Mg(II) compared to Ca(II). Interaction of bound cations with carbonitrile reduces the energies of the MOs involved in the proposed σ-p conjugated network. The planar malononitrile-Be(II) complex possibly involves a π-network with a cationic methylene carbon. Fabricated potentiometric chemical sensors show distinct signal patterns that can be exploited in sensor array applications.
    Matched MeSH terms: Computer-Aided Design
  13. Finite element analysis of zygomatic implants in intrasinus and extramaxillary approaches for prosthetic rehabilitation in severely atrophic maxillae
    Ishak MI, Kadir MR, Sulaiman E, Kasim NH
    Int J Oral Maxillofac Implants, 2013 May-Jun;28(3):e151-60.
    PMID: 23748334 DOI: 10.11607/jomi.2304
    To compare the extramaxillary approach with the widely used intrasinus approach via finite element method.
    Matched MeSH terms: Computer-Aided Design
  14. Edentulous arch treatment with a CAD/CAM screw-retained framework and cemented crowns: a clinical case report
    Baig MR, Rajan G, Rajan M
    J Oral Implantol, 2009;35(6):295-9.
    PMID: 20017646 DOI: 10.1563/AAID-JOI-D-09-00012R1.1
    This article describes the rehabilitation of a completely edentulous patient using a milled titanium implant framework and cemented crowns. This combined approach significantly offsets unsuitable implant position, alignment, or angulation, while ensuring the easy retrievability, repair, and maintenance of the prosthesis. Hence, the dual advantage of cemented-retained crowns reproducing appropriate esthetics and function, irrespective of where the screw access openings are located in the substructure, can be obtained, along with the splinting effect and management of soft and hard tissue deficits achievable with a screw-retained framework.
    Matched MeSH terms: Computer-Aided Design*
  15. Evaluation of the marginal fit of a zirconia ceramic computer-aided machined (CAM) crown system
    Baig MR, Tan KB, Nicholls JI
    J Prosthet Dent, 2010 Oct;104(4):216-27.
    PMID: 20875526 DOI: 10.1016/S0022-3913(10)60128-X
    The marginal fit of crowns is a concern for clinicians, and there is no conclusive evidence of any one margin configuration yielding better results than others in terms of marginal fit.
    Matched MeSH terms: Computer-Aided Design*
  16. Percentage of mesh reduction appropriate for designing digital obturator prostheses on personal computers
    Farook TH, Abdullah JY, Jamayet NB, Alam MK
    J Prosthet Dent, 2021 Feb 15.
    PMID: 33602541 DOI: 10.1016/j.prosdent.2020.07.039
    STATEMENT OF PROBLEM: Computer-aided design (CAD) of maxillofacial prostheses is a hardware-intensive process. The greater the mesh detail is, the more processing power is required from the computer. A reduction in mesh quality has been shown to reduce workload on computers, yet no reference value of reduction is present for intraoral prostheses that can be applied during the design.

    PURPOSE: The purpose of this simulation study was to establish a reference percentage value that can be used to effectively reduce the size and polygons of the 3D mesh without drastically affecting the dimensions of the prosthesis itself.

    MATERIAL AND METHODS: Fifteen different maxillary palatal defects were simulated on a dental cast and scanned to create 3D casts. Digital bulbs were fabricated from the casts. Conventional bulbs for the defects were fabricated, scanned, and compared with the digital bulb to serve as a control. The polygon parameters of digital bulbs were then reduced by different percentages (75%, 50%, 25%, 10%, 5%, and 1% of the original mesh) which created a total of 105 meshes across 7 mesh groups. The reduced mesh files were compared individually with the original design in an open-source point cloud comparison software program. The parameters of comparison used in this study were Hausdorff distance (HD), Dice similarity coefficient (DSC), and volume.

    RESULTS: The reduction in file size was directly proportional to the amount of mesh reduction. There were minute yet insignificant differences in volume (P>.05) across all mesh groups, with significant differences (P

    Matched MeSH terms: Computer-Aided Design
  17. A virtual analysis of the precision and accuracy of 3-dimensional ear casts generated from smartphone camera images
    Farook TH, Rashid F, Jamayet NB, Abdullah JY, Dudley J, Khursheed Alam M
    J Prosthet Dent, 2022 Oct;128(4):830-836.
    PMID: 33642077 DOI: 10.1016/j.prosdent.2020.12.041
    STATEMENT OF PROBLEM: The anatomic complexity of the ear challenges conventional maxillofacial prosthetic rehabilitation. The introduction of specialized scanning hardware integrated into computer-aided design and computer-aided manufacturing (CAD-CAM) workflows has mitigated these challenges. Currently, the scanning hardware required for digital data acquisition is expensive and not readily available for prosthodontists in developing regions.

    PURPOSE: The purpose of this virtual analysis study was to compare the accuracy and precision of 3-dimensional (3D) ear models generated by scanning gypsum casts with a smartphone camera and a desktop laser scanner.

    MATERIAL AND METHODS: Six ear casts were fabricated from green dental gypsum and scanned with a laser scanner. The resultant 3D models were exported as standard tessellation language (STL) files. A stereophotogrammetry system was fabricated by using a motorized turntable and an automated microcontroller photograph capturing interface. A total of 48 images were captured from 2 angles on the arc (20 degrees and 40 degrees from the base of the turntable) with an image overlap of 15 degrees, controlled by a stepper motor. Ear 1 was placed on the turntable and captured 5 times with smartphone 1 and tested for precision. Then, ears 1 to 6 were scanned once with a laser scanner and with smartphones 1 and 2. The images were converted into 3D casts and compared for accuracy against their laser scanned counterparts for surface area, volume, interpoint mismatches, and spatial overlap. Acceptability thresholds were set at <0.5 mm for interpoint mismatches and >0.70 for spatial overlap.

    RESULTS: The test for smartphone precision in comparison with that of the laser scanner showed a difference in surface area of 774.22 ±295.27 mm2 (6.9% less area) and in volume of 4228.60 ±2276.89 mm3 (13.4% more volume). Both acceptability thresholds were also met. The test for accuracy among smartphones 1, 2, and the laser scanner showed no statistically significant differences (P>.05) in all 4 parameters among the groups while also meeting both acceptability thresholds.

    CONCLUSIONS: Smartphone cameras used to capture 48 overlapping gypsum cast ear images in a controlled environment generated 3D models parametrically similar to those produced by standard laser scanners.

    Matched MeSH terms: Computer-Aided Design
  18. Design and fabrication of scaffolds for anatomic bone reconstruction
    Hollister SJ, Lin CY, Lin CY, Schek RD, Taboas JM, Flanagan CL, et al.
    Med J Malaysia, 2004 May;59 Suppl B:131-2.
    PMID: 15468853
    Matched MeSH terms: Computer-Aided Design*
  19. Fulltext An alternate method to springback compensation for sheet metal forming
    Siswanto WA, Anggono AD, Omar B, Jusoff K
    ScientificWorldJournal, 2014;2014:301271.
    PMID: 25165738 DOI: 10.1155/2014/301271
    The aim of this work is to improve the accuracy of cold stamping product by accommodating springback. This is a numerical approach to improve the accuracy of springback analysis and die compensation process combining the displacement adjustment (DA) method and the spring forward (SF) algorithm. This alternate hybrid method (HM) is conducted by firstly employing DA method followed by the SF method instead of either DA or SF method individually. The springback shape and the target part are used to optimize the die surfaces compensating springback. The hybrid method (HM) algorithm has been coded in Fortran and tested in two- and three-dimensional models. By implementing the HM, the springback error can be decreased and the dimensional deviation falls in the predefined tolerance range.
    Matched MeSH terms: Computer-Aided Design*
  20. Fulltext Analysis of glass-reinforced epoxy material for radio frequency resonator
    Zaman MR, Islam MT, Misran N, Yatim B
    ScientificWorldJournal, 2014;2014:831435.
    PMID: 24977230 DOI: 10.1155/2014/831435
    A radio frequency (RF) resonator using glass-reinforced epoxy material for C and X band is proposed in this paper. Microstrip line technology for RF over glass-reinforced epoxy material is analyzed. Coupling mechanism over RF material and parasitic coupling performance is explained utilizing even and odd mode impedance with relevant equivalent circuit. Babinet's principle is deployed to explicate the circular slot ground plane of the proposed resonator. The resonator is designed over four materials from different backgrounds which are glass-reinforced epoxy, polyester, gallium arsenide (GaAs), and rogers RO 4350B. Parametric studies and optimization algorithm are applied over the geometry of the microstrip resonator to achieve dual band response for C and X band. Resonator behaviors for different materials are concluded and compared for the same structure. The final design is fabricated over glass-reinforced epoxy material. The fabricated resonator shows a maximum directivity of 5.65 dBi and 6.62 dBi at 5.84 GHz and 8.16 GHz, respectively. The lowest resonance response is less than -20 dB for C band and -34 dB for X band. The resonator is prototyped using LPKF (S63) drilling machine to study the material behavior.
    Matched MeSH terms: Computer-Aided Design
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