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- ItemStructural and electrical characterization of cadmium phosphate glasses doped with different concentration of sodium chloride(IOP Publishing, 2024-12-01) Assayed, Ghada A.I.; Shaheen, Adel A; Alsoud, Ammar Awadallah Ahmad; Al-Bashaish, Saleh R.; Mousa, Marwan Suleiman; Knápek, Alexandr; Sobola, DinaraThe electrical characteristics of cadmium phosphate glasses doped with varying concentrations of sodium chloride [ Cd-3( PO4)(2)](1-x) [ NaCl](x) , where x = 0, 2, 4 ,6 mol.% NaCl, were investigated with respect to both dopant levels and temperature. Electrical impedance spectroscopy was employed, and impedance measurements were taken across the frequency spectrum from 10(2) Hz to 10(6) Hz. Samples were characterized by scanning electron microscopy-energy dispersive x-ray spectroscopy, x-ray diffraction analysis and Fourier Transform Infrared Spectroscopy. The fi ndings revealed a decrease in bulk resistance with increasing temperature and dopant concentration, indicating a rise in DC- conductivity and suggesting a semiconducting behavior in the material. Moreover, the activation energy values were noted to decrease as dopant concentration increased. Analysis of the AC-conductivity variation with frequency delineated two distinct regions: a low-frequency region where AC-conductivity increased with frequency, indicative of a "pumping force" effect aiding charge carrier movement through various conduction states, and a high-frequency region or frequency-independent zone signifying a transition towards a more ohmic behavior in the material. The study highlighted a decrease in both the dielectric constant and dielectric loss with rising temperature and frequency across all dopant concentrations. Furthermore, the Reaction Coefficient "s" was found to be less than one, suggesting that the conduction mechanism can be elucidated in terms of the Correlated Barrier Hopping ( CBH ) model.
- ItemA 0.3 V Current Differencing Buffered Amplifier and Its Application in Current-Mode Third-Order Low-Pass Filters(MDPI, 2025-05-25) Khateb, Fabian; Kumngern, Montree; Kulej, TomaszThis paper introduces an innovative low-voltage, low-power current differencing buffered amplifier (CDBA). The proposed CDBA utilizes a bulk-driven MOS transistor operating in the subthreshold region, allowing it to function effectively at low supply voltages while minimizing power consumption, making it suitable for sensor and biomedical applications. To demonstrate the performance of the proposed CDBA, it is incorporated into the design of a current-mode, third-order low-pass filter that is specifically tailored for bio-sensing applications. Both the CDBA and the low-pass filter are designed and simulated in Cadence Virtuoso using the TSMC 0.18 mu m CMOS process. The CDBA operates at a supply voltage of 0.3 V, consuming 170 nW of power, while the third-order low-pass filter achieves a dynamic range of 57.2 dB with a total harmonic distortion (THD) of 1%.
- ItemA low-cost picowatt calorimeter using a flexible printed circuit board(Nature Portfolio, 2025-03-27) Zhu, Hanliang; Zhang, Yue; Wang, Lan; Brodský, Jan; Gablech, Imrich; Feng, Jianguo; Yan, Qi-Long; Yang, Shujie; Lee, Luke P.; Neužil, PavelCalorimetry is crucial in biology, chemistry, physics, and pharmaceutical research, enabling the detection of heat changes at nanowatt and picowatt levels. However, traditional calorimetry systems are often limited by high costs and complex fabrication processes. Here, we reduce the cost and fabrication complexity of microcalorimeters by utilizing widely available flexible printed circuit manufacturing processes. This device achieves temperature and power resolutions of 6 K and 654pW in vacuum. Its feasibility is validated across a wide range of measurements, including salt crystallization, protein crystallization, and cellular metabolism. Our concept enhances the accessibility of microcalorimeters for high-resolution thermal analysis, which is challenging for conventional calorimeters.
- Item0.5-V High-Order Universal Filter for Bio-Signal Processing Applications(MDPI, 2025-04-03) Kumngern, Montree; Khateb, Fabian; Kulej, Tomasz; Lerkvaranyu, SomkiatIn this paper, a novel multiple-input operational transconductance amplifier (MI-OTA) is proposed. The MI-OTA can be obtained by using the multiple-input bulk-driven MOS transistor (MIBD MOST) technique. The circuit structure is simple, can operate with a supply voltage of 0.5 V, and consumes 937 pW at a current setting of 625 pA. The proposed MI-OTA was used to implement a high-order multiple-input voltage-mode universal filter. The proposed filter can provide non-inverting and inverting low-pass, high-pass, band-pass, band-stop, and all-pass transfer functions to the same topology. In addition, it has a high input impedance and does not need any inverted input signals, so there is no additional buffering circuit. The proposed filter can be used for biological signal processing. The proposed MI-OTA and the second-order universal filter were simulated in Cadence using CMOS process parameters of 0.18 mu m from TSMC to verify the functionality and performance of the new structures.
- ItemNovel Multiple-Input Single-Output Shadow Filter with Improved Passband Gain Using Multiple-Input Multiple-Output DDTAs(MDPI, 2025-03-31) Kumngern, Montree; Khateb, Fabian; Kulej, TomaszThis paper presents a multiple-input single-output (MISO) shadow filter implemented using multiple-input differential difference transconductance amplifiers (MI-DDTAs). The MI-DDTA's multiple inputs are realized through the multiple-input bulk-driven MOS transistor (MI-BD MOST) technique. Leveraging the multiple-input capability of the DDTA, various filter responses-low-pass filter (LPF), high-pass filter (HPF), band-pass filter (BPF), band-stop filter (BSF), and all-pass filter (APF)-can be efficiently achieved by appropriately configuring the input signals. The natural frequency and quality factor of the shadow filter can be independently tuned using external amplifiers. Unlike conventional shadow filters, where adjusting the quality factor or natural frequency impacts the passband gain, this design ensures a constant unity passband gain. The MI-DDTA operates at a supply voltage of 0.5 V and consumes 385.8 nW of power for setting current Iset = 14 nA. The proposed MI-DDTA and shadow filter are designed and validated through simulations in the Cadence design environment, using a 0.18 mu m CMOS process provided by TSMC (Taiwan Semiconductor Manufacturing Company Limited).