Tidak Diketahui Pusat Pengajian - Tesis

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    High Linearity And High Efficiency Cmos Power Amplifier And Up-conversion Mixer For 5g New Radio Sub-6 Ghz
    (2024-09)
    Gunasegaran, Premmilaah
    Fifth Generation (5G) New Radio (NR) is the latest wireless technology designed to meet the growing demands of modern networks and connected devices, but it imposes stringent requirements on transmitters, leading to potential reductions in efficiency due to high power usage. In this study, a highly efficient and linear CMOS power amplifier (PA) and up-conversion mixer were developed for 5G NR Sub-6GHz applications. A mixer-based linearizer was integrated at the PA's input to enhance performance across a wide frequency range, ensuring the system maintained high efficiency and linearity even with a 3 dB reduction in output power. The integrated CMOS PA and mixer, fabricated using 130 nm CMOS technology, cover a 1 GHz bandwidth from 4 GHz to 5 GHz. Measurement results demonstrated a gain of over 30 dB, with maximum output power ranging from 23.85 to 23.39 dBm, peak power-added efficiency (PAE) from 41.3% to 41.04%, and an output third-order intercept point (OIP3) between 31.38 and 32.53 dBm. The system's ability to maintain linearity was confirmed through testing with a 16 QAM signal, highlighting the innovation of the mixer-based linearizer integrated with the mixer before feeding into the PA.
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    Characterisation Of Pectate Lyase Pelq1 From Saccharobesus Litoralis
    (2024-01)
    Melissa Lian, Qianyue
    The pelQ1 gene from the marine bacterium Saccharobesus litoralis CCB-QB4 encodes a pectate lyase that consists of two domains, which are polysaccharide lyase family 1 (PL1) and carbohydrate-binding module family 13 (CBM13). CBM13 which is involved in substrate binding is often found in pectate lyases (Pels) from marine sources but not terrestrial sources. Moreover, the study of marine Pels is lacking since pectin is not one of the major sources of carbohydrates in the marine environment. Therefore, this study aimed to elucidate the cleaving mechanism of PelQ1 by comparing the activity of the full-length enzyme (PelQ1-Full) and the truncated enzyme with CBM13 removed (PelQ1-PL1). Both enzymes were cloned, purified, characterized, and their cleaving mechanisms were elucidated. PelQ1-Full exolytically cleaved the substrate polygalacturonic acid (PGA) to produce a majority of unsaturated trigalacturonic acid; however, it cleaved the citrus pectin (CP) into a majority of unsaturated digalacturonic acid when high enzyme concentrations were used. PelQ1-Full worked in an optimal condition of pH 9.0, 30°C, and 0.6 mM CaCl2. Comparison between the two enzymes showed that there was a slightly higher catalytic efficiency (kcat/KM) towards PGA than CP, while TLC results showed that the CBM13 domain might help substrate binding. The AlphaFold homology model of the PL1 domain showed that it had a structure of parallel β-helix and a high sequence similarity with PelC of Dickeya dadantii. The CBM13 domain showed a structure of β-trefoil fold similar to other CBM13 domains.
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    Multiband Cmos Power Amplifierwith Integrated High-Q Compact Inductor For Lora Application
    (2023-05)
    Arvind Singh Rawat
    In the wide development of the Internet of Things (IoT), Machine-to-Machine (M2M), and biomedical applications in research and standardization, the spectrum of sub-GHz has received fresh attention. Long-range (LoRa) devices use the sub-GHz frequency bands to operate. The size of the chip becomes bigger when designed to target low frequencies and it is mainly contributed by the inductors. In this research, a high-performance CMOS power amplifier (PA) with a novel custom shape, high Qfactor compact inductor (HQCI) is fabricated in 130 nm, 6-metal layers CMOS process.
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    Development Of Lab On Printed Circuit Board Based Heavy Metal Detection
    (2023-03)
    Beh, Khi Khim
    Heavy metal contamination in water sources is a significant environmental problem that poses a threat to public health. Electrochemical detection is a promising approach to detecting and quantifying heavy metals in water, due to the high sensitivity and selectivity it provides. However, traditional working electrodes, such as glassy carbon and mercury, are not ideal for detecting heavy metals due to limitations such as low sensitivity and toxicity. To address these limitations, this study aimed to improve the design and fabrication complexity of electro-analytical sensors by implementing a conventional Printed Circuit Board (PCB) fabrication technique. The fabricated sensor has achieved miniaturization of 40% compared to existing electrochemical sensors. According to cyclic voltammetry (CV) measurements, the fabricated sensor can produce a reversible peak reaction with different scan rates between 100 mV/s to 10 mV/s achieving a peak current ratio of 1. The modified Graphene Oxide (GO) of 0.2 mg/ml on the working electrode was explored as a sensing material due to its high sensitivity and selectivity in detecting heavy metals such as lead and cadmium, with an improvement of 45% in the detection of these metals. The optimum conditions for the detection of lead and cadmium were determined with a 10-minute accumulation time, -0.4 v reduction potential, 7-minute reduction time, and pH 4.0 of 0.1 M HCL buffer solution.
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    Piezoelectric Micro Ultrasonic Transducer (Pmut) With Fluidic Backing Layer As A Sensing Mechanism For Short Distance Underwater Microphone Application
    (2022-02)
    Ahmad, Khairul Azman
    Piezoelectric micro ultrasonic transducer (PMUT) is vital for underwater microphone (hydrophone) applications. Hydrophone is generally used for listening or receiving any acoustic signal in underwater. Several studies have documented that PMUT served as underwater hydrophone with low receiving sensitivity and narrow operation bandwidth. The received acoustic signals with low receiving sensitivity are not accurate due to interference by unwanted signal. Acoustic transducers with narrow bandwidth were effected low resolution for underwater acoustic imaging. Narrow bandwidth transducers were captured for certain frequency only and it were difficult to catch acoustic signal at a long range frequency. In imaging, it is important the transducers can receive the signal for a long range of frequencies. The objectives of this study to increase the low receiving sensitivity transducer in the range of 300 kHz to 800 kHz and widen the narrow frequency bandwidth underwater ultrasonic transducer. Subsequently objectives are a PMUT designed using d33 mode piezoelectric structure, flexural membrane and fluidic backing layer.