Current Issue : October-December Volume : 2025 Issue Number : 4 Articles : 5 Articles
This paper presents an active phase shifter for phased array system applications, implemented using 0.18 μm SiGe BiCMOS technology. The phase shifter circuit consists of a wideband quadrature signal generator, a vector modulator, an input balun, and an output balun. To enhance the bandwidth, a polyphase filter is employed as the quadrature signal generator, and a two-stage RC-CR filter with a highly symmetrical miniaturized layout is cascaded to create multiple resonant points, thus extending the phase shifter’s bandwidth to cover the required range. The gain of the variable-gain amplifier within the vector modulator is adjustable by varying the tail current, thereby enlarging the range of selectable points, improving phase-shifting accuracy, and reducing gain fluctuations. The measurement results show that the proposed active phase shifter achieves an RMS phase error of less than 2◦ and a gain variation ranging from −1.2 dB to 0.1 dB across a 20 GHz to 30 GHz bandwidth at room temperature. The total chip area is 0.4 mm2, with a core area of 0.165 mm2, and consumes 19.5 mW of power from a 2.5 V supply....
Flexible thin-film capacitors have gained a lot of attention in energy storage applications because of their high energy storage densities and efficient charge–discharge performances. Among these materials, antiferroelectric compounds with low residual polarization and strong saturation polarization have shown great promise. However, their comparatively low breakdown strength continues to be a major issue restricting further developments in their energy storage performance. While La3+ doping has been explored as a means to enhance the energy storage capabilities of antiferroelectric thin films, the specific influence of La3+ on breakdown strength and the underlying mechanism of phase transitions have not been thoroughly investigated in existing research. In this study, Pb1−3x/2LaxZrO3 thin films were successfully synthesized and deposited on mica substrates via the sol–gel process. By varying the concentration of La3+ ions, a detailed examination of the films’ microstructures, electrical properties, and energy storage performances was carried out to better understand how La3+ doping influences both breakdown strength and energy storage characteristics. The results show that doping with La3+ significantly improves the breakdown strength of the films, reduces the critical phase transition electric field (EF-EA), and enhances their energy storage capabilities. Notably, the Pb0.91La0.06ZrO3 thin film achieved an impressive energy storage density of 34.9 J/cm3 with an efficiency of 58.3%, and at the maximum electric field strength of 1541 kV/cm, the recoverable energy density (Wrec) was 385% greater than that of the PbZrO3 film. Additionally, the film still maintains good energy storage performance after 107 cycles and 104 bending cycles. These findings highlight the potential of flexible antiferroelectric Pb0.91La0.06ZrO3 thin films for future energy storage applications....
This article explores the transformative shift from FinFET to RibbonFET (Gate-All-Around) transistor architecture in semiconductor technology, with a specific focus on analog integrated circuit design implications. The article analyzes the fundamental structural advantages of RibbonFET technology, highlighting its enhanced electrostatic control, performance improvements, and scaling benefits compared to traditional FinFET designs. Detailed considerations of layout techniques for analog applications are presented, including device structure adaptations, parasitic management strategies, and matching optimizations essential for precision analog circuits. The article extends to power and signal integrity challenges, examining power delivery networks, noise isolation techniques, thermal considerations, and signal integrity preservation approaches. Implementation case studies in highspeed communication circuits demonstrate the practical applications of these advanced semiconductor technologies, while future directions outline key transition strategies and optimization methodologies critical for the successful integration of RibbonFET technology in next-generation analog circuit designs....
The explosive demand for high-performance secondary power sources in artificial intelligence (AI) has brought significant opportunities for low-voltage GaN devices. This paper focuses on research on high-efficiency and high-reliability low-voltage p-GaN gate HEMTs with a gate–drain distance, LGD, of 1 to 3 μm in our pilot line, manufactured on 6-inch Si using a CMOS-compatible process, with extraordinary wafer-level uniformity. Specifically, these fabricated p-GaN gate HEMTs with an LGD of 1.5 μm demonstrate a blocking voltage of over 180 V and a high VTH of 1.6 V and exhibit a low RON of 2.8 Ω·mm. It is found that device structure optimization can significantly enhance device reliability. That is, through the dedicated optimization of source field plate structure and interlayer dielectric (ILD) thickness, the dynamic ON-resistance, RON, degradation of devices with an LGD of 1.5 μm was successfully suppressed from 60% to 20%, and the VTH shift was significantly reduced from 1.1 to 0.5 V. Further, the devices also passed preliminary gate bias stress and high-voltage OFF-state stress tests, providing guidance for preparing high-performance, low-voltage p-GaN gate HEMTs in the future....
Given the high cost and limited availability of noble-metal-based catalysts in acidic media water electrolysis, developing cost-effective and high-performance non-noble metal catalysts is crucial for realizing large-scale hydrogen production. In this study, Fe-, Co-, and Ni-doped MoSe2 nanomaterials were synthesized via chemical vapor deposition, and their electrocatalytic performance for the hydrogen evolution reaction (HER) was systematically evaluated. Characterization techniques including X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy were used to confirm the incorporation of doping elements and investigate their effects on the crystal structure and morphology of MoSe2. Electrochemical tests, including linear sweep voltammetry and cyclic voltammetry, revealed that the doping of Fe, Co, and Ni significantly enhanced the HER catalytic activity of MoSe2, with the Co-doped sample exhibiting the best performance, showing an overpotential of 0.293 V at 100 mA/cm−2 and a Tafel slope of 47 mV/dec. Furthermore, density functional theory calculations were employed to analyze the adsorption energy of hydrogen atoms on the catalysts, providing deeper insights into the role of doping in tuning the catalytic activity of MoSe2. This study offers new theoretical support and experimental evidence for the application of transition metal-doped MoSe2 in electrocatalysis....
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