Now showing 1 - 4 of 4
  • Publication
    An innovative single development process for integrated optical Mach-Zehnder interferometer pattern transfer
    ( 2017-01-01) ;
    Lau Kuen Yao
    ;
    Kang Nan Khor
    ;
    Abdul Wahid M. H.
    ;
    ;
    Vithyacharan Retnasamy
    ;
    Mukhzeer Mohamad Shahimin
    Integrated optical Mach-Zehnder interferometer (IO-MZI) has been widely researched for various usage including for biosensor application. However, the success rate of IO-MZI pattern transfer has been low using the conventional multidevelopment process. One of the main factors is the particle contamination due to the practice of reused developer bath. In this work, an innovative single development process had been proposed with the utilization of the same conventional set-up but with a different protocol. The concept of this method is the estimation of total development time based on the calculated development rate. By doing so, the development process can be completed with only one immersion of the substrate in the developer bath. Besides, the manipulation of development rate by varying exposure time in this work also had revealed the possibility of manipulation of line-width based on the exposure time. In short, the proposed single development process has increased the success rate of IO-MZI pattern transfer from 30% (multi-development method) to 90%.
  • Publication
    Electromagnetic properties performance of MWCNTs/Polyester composites in X-band
    ( 2018)
    Y. S. Lee
    ;
    F. H. Wee
    ;
    K. Y. You
    ;
    C. Y. Lee
    ;
    Y. Y. Lee
    ;
    L. Zahid
    ;
    ;
    M. S. Shakhirul
    ;
    ;
    E. M. Cheng
    In this paper presents nano-composites based on polyester (PE) matrix with multi-walled carbon nanotubes (MWCNTs) as fillers have been developed for microwave absorbing materials. The MWCNTs/PE composite samples were fabricated with different weight ratio of MWCNTs (3 wt%, 5 wt%, and 10 wt%). The electromagnetic properties of different MWCNTs/PE composite have been determined by using rectangular waveguide technique and Agilent material measurement software. Moreover, the reflection loss (microwave absorption) of MWCNTs/PE composite have been calculated based on the basis of transmission line theory. The performance of electromagnetic properties and microwave absorption of MWCNTs/PE composite were analyzed in X-band frequency. The dielectric loss properties of the composite are increse with increasing in MWCNTs weight ratio. The microwave absorption results show that such 3 wt% MWCNTs/PE composites sample with 4 mm thickness has achieved less than -10 dB values (< 90 % microwave absorption) of reflection loss.
  • Publication
    Electrical Tree Image Segmentation Using Hybrid Multi Scale Line Tracking Algorithm
    Electrical trees are an aging mechanism most associated with partial discharge (PD) activities in crosslinked polyethylene (XLPE) insulation of high-voltage (HV) cables. Characterization of electrical tree structures gained considerable attention from researchers since a deep understanding of the tree morphology is required to develop new insulation material. Two-dimensional (2D) optical microscopy is primarily used to examine tree structures and propagation shapes with image segmentation methods. However, since electrical trees can emerge in different shapes such as bush-type or branch-type, treeing images are complicated to segment due to manifestation of convoluted tree branches, leading to a high misclassification rate during segmentation. Therefore, this study proposed a new method for segmenting 2D electrical tree images based on the multi-scale line tracking algorithm (MSLTA) by integrating batch processing method. The proposed method, h-MSLTA aims to provide accurate segmentation of electrical tree images obtained over a period of tree propagation observation under optical microscopy. The initial phase involves XLPE sample preparation and treeing image acquisition under real-time microscopy observation. The treeing images are then sampled and binarized in pre-processing. In the next phase, segmentation of tree structures is performed using the h-MSLTA by utilizing batch processing in multiple instances of treeing duration. Finally, the comparative investigation has been conducted using standard performance assessment metrics, including accuracy, sensitivity, specificity, Dice coefficient and Matthew’s correlation coefficient (MCC). Based on segmentation performance evaluation against several established segmentation methods, h-MSLTA achieved better results of 95.43% accuracy, 97.28% specificity, 69.43% sensitivity rate with 23.38% and 24.16% average improvement in Dice coefficient and MCC score respectively over the original algorithm. In addition, h-MSLTA produced accurate measurement results of global tree parameters of length and width in comparison with the ground truth image. These results indicated that the proposed method had a solid performance in terms of segmenting electrical tree branches in 2D treeing images compared to other established techniques.
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  • Publication
    Optimization of line pattern transfer of integrated optical Mach-Zender interferometer for optical sensor
    Conventional photolithography usually used in in-house fabrication process to transfer the design of line pattern. This research lays the foundation for the optimization of photo lithography process for line pattern transfer of complex optical circuitry. Integrated Optical Mach-Zehnder Interferometer (IO-MZI) has been widely used for biosensor applications. In order to have a significant advantage in improving the sensitivity of the biosensor, it is crucial to get a good, consistent and conformal line pattern transfer with a fine width; in our case is approximately 4μm and 3cm length. However, the success rate of 10-MZI pattern transfer had been low using the conventional multi-development process. One of the main factors is the particle contamination due to the usage of reused developer bath. In this work, an innovative single development process had been proposed with the utilization of the same conventional set-up. The concept of this method centers around the optimization of the total development time based on the experimental and mathematical model of the development rate. By doing so, the development process can be completed with only one immersion of the substrate in the developer bath. Due to this reason, the aim of this project is to improve the success rate and repeatability of photolithography process without compromising the resolution and vertical profile, which is necessary for the optical waveguide fabrication. Besides, the manipulation of development rate by varying exposure time in this work also revealed the possibility of manipulation of linewidth based on the exposure time. In short, the proposed single development process had increased the success rate of 10-MZI pattern transfer from 300/o (multi-development method) to 90% (single-development method). The characterization of in-house single development fabrication process has improved the current photolithography setup for line pattern transfer and complex design pattern transfer.
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