Small form factor CMOS mmw Wilkinson Combiner with Stacked Coupling
AbstractThis work presents the design and fabrication of a 60-GHz Wilkinson power combiner with stacked coupling and capacitive loading on a 0.18μm CMOS process. Stacked microstrip lines are employed for compact coupling, and capacitive loading is included to enhance impedance matching and achieve broadband performance. Compared to previous works based on mixed edge-stacked coupling or Wilkinson structures based on transformers, the new architecture applies solely stacked coupling to prevent chip area wastage and simplify manufacturing. Capacitive elements are employed to enhance the electrical length without occupying physical area to enable efficient signal combination and reduce transmission loss at millimeter-wave frequencies. With the demonstration in a 0.18μm CMOS technology, the combiner shows operation success at the center frequency of 60 GHz with 1.49 dB insertion loss, 17 dB and 20 dB return losses at input port and output port respectively, and amplitude imbalance of 0.2 db. The chip occupies a small area of 0.5023 mm² with a highly integrate able and CMOS-compatible approach to RF front-end modules for next-generation wireless communication systems based on 60 GHz.
Full Coverage CMOS I/Q-Based Phase Shifter for a 5G application
Abstract
This paper discusses the configuration of an active 3600 continuous phase shifter based on stacked voltage gain amplifier (VGA) architecture with an active combiner fabricated in 180 nm CMOS technology. The design consists of differential paths for the signals: 00 and 1800 that pass-through VGAs whose output is enabled by gate voltages V1 and V2. Full-range phase tuning from -1800 to +1800 is achieved by sweeping V1 from 0 V to 1.8 V, while V2 is swept inversely from 1.8 V to 0 V. The circuit operates within the range of 1.0-1.5 GHz, with S11 being lower than -12.5 dB and S22 being lower than -13 dB. S21 varies in between -6 dB and -12 dB, which corresponds to linear gains from 0.23988 to 0.50118. The output amplitude varies between 0.0 and 0.2613. The verified phase states include 0 ~ -1800 and 0 ~ +1800 in addition to the total phase of 3600 from the active phase shifter. The system also supports phase resolution steps of 220, 450, 900, 1800, and 3600, allowing for fine control in beam steering. The NMOS-only active combiner is free from passive components, allowing it to be integrated into compact, wideband, and power-efficient adaptive RF beamforming systems.
Biocompatible ZIF-8 and MAF-7 Nanoparticles for Enzyme Encapsulation and Catalytic Delivery
Abstract
Metal-organic frameworks (MOFs) have gained much attention and are widely studied for their potential in applications such as drug delivery, biocatalysis, environmental sensing, and gas storage. The adaptability, high surface area, and unique structural properties of MOF nanoparticles, including tunable porosity and biocompatibility, offer novel solutions across industries, particularly in biotechnology and materials science, by enabling controlled and sustained release. In this study, we investigate using ZIF-8 and MAF-7 nanoparticles as protective matrices for enzymes, including bovine serum albumin, urease, and cytochrome P450. The encapsulation process preserves the enzymatic activity of these proteins ensuring their stability and functional retention. These findings demonstrate the potential of MOFs as reliable platforms for enzyme stabilization and delivery, opening doors for further applications in enzyme-based therapies, biocatalysis, and drug delivery. The adaptable properties of these nanoparticles make them ideal for customization across various fields, such as sensing and gas storage, where they are employed for detecting pollutants and storing gases like carbon dioxide and hydrogen. Overall, this research highlights the broad applicability and versatility of MOFs, positioning them as functional materials with promising applications in biotechnology, environmental science, and materials engineering.
Analysis of mortality rate, hematobiochemical effects, and histopathological changes in Goldfish (Carassius auratus) exposed to Nicotine
Abstract
As interest in environmental pollution has increased for decades, research on the effects of various pollutants on ecosystems is rapidly progressing. Tobacco butts are the most waste on the coast of Korea, and contain toxic substances such as benzopyrene, formaldehyde and cyanide. Also, the main substances are known as carbon monoxide, tar, and nicotine. In this study, the toxicity of goldfish exposed to nicotine at concentrations of 0, 2.5, 5.0, 7.5, and 10.0 ppm for 120 h was evaluated. The 50% lethal dose (LD50) of nicotine for goldfish was determined to be 5.0 ppm, and concentrations above 7.5 ppm resulted in 100% mortality within 24 hours of exposure. Hematobiochemical analysis of goldfish exposed to nicotine showed significant increases in GLU, ALT, AST, and BUN, and decreases in ALP compared to the control group, suggest-ing that nicotine exposure caused damage to the liver and kidneys of the fish. In addition, histopatho-logical analysis results showed hyperplasia of the gill primary lamellae epithelium, cloudy swelling of the renal tubular epithelium, hepatic congestion, and hyaline degeneration in liver cells, which were consistent with the results of liver and kidney damage by hematobiochemical analysis. This study provides insight into the potential impacts of nicotine exposure on fish ecosystems and highlights the need for continued research on nicotine contamination in natural aquatic systems.
Could the blazar TXS 0506+056 be gravitationally lensed?
Abstract
Currently, two cases of strong gravitational lensing of blazars are known: B0218+357 and PKS 1830-211. We speculate that the source TXS 0506+056 might also be influenced by lensing. TXS 0506+056 is the first active galactic nucleus identified as a source of extremely-high-energy neutrino event (IceCube-170922A). Starting from 2016, it demonstrates a rather complex jet morphology: radio observations at 8 and 15 GHz reveal a well-defined arc-like structure. Such a morphology is atypical for blazars but naturally appears in case of strong gravitational lensing. Here we discuss a possibility that TXS 0506+056 might be lensed by an intervening black hole. The standard approach to gravitational lens modeling assumes that both the source and the lens are essentially flat surfaces in space. While it’s applicable to a black hole acting as a lens, it might not be the case for a blazar with a jet directed towards observer, i.e. approaching the lens. We developed a model accounting for change in distance between the lens and the jet. When the jet crosses the lens plane, the jet images are continuous but not smooth anymore. This particular feature can be used as an observational diagnostic for such a scenario. We find a set of most probable configurations of the gravitational lens system — the lens mass, the distance between the source and the lens, their relative location on the celestial sphere and the viewing angle of the jet — which reproduce the observed morphology in TXS 0506+056. The solution is not unique due to discovered degeneracies between the lens mass, the distance and the viewing angle. We conclude that, in principle, the blazar TXS 0506+056 could be gravitationally lensed and suggest to use a time delay between jet images (since the blazar is a highly variable source) as an additional constraint to break the degeneracies.
Search for a correlation between solar activity and the power of radiation belts in the Earth's magnetosphere
Abstract
In this paper we investigated the dependence of the power of the radiation belts in the Earth's magnetosphere on solar activity. We used data from the IREM charged particle detector installed on board the INTEGRAL orbital observatory. This device is designed to register particles when the observatory enters the radiation belts of the Earth's magnetosphere and issue a signal that turns off the delicate scientific equipment high voltage to avoid its failure. During the shutdown of the main scientific equipment the IREM device continued to operate and collected data on the number of registered particles. This allowed us to analyze a quasi-continuous row of charged particles in the radiation belts lasting for 21 years (from 2003 to 2023) of the observatory's operation. The average values of the electron registration rate in the selected low-energy channel were calculated, peak values exceeding the average by 400 standard deviations were identified, and their visualization is presented. We plotted the radiation belt positions using the spacecraft coordinates in the inertial geocentric reference frame. We performed a correlation of solar activity and the electron flux density in the radiation belts. The results witness of some correlation between solar activity and the power of the radiation belts.
A High-Resolution CMOS Voltage Reference for Battery Management System Semiconductor Design
Abstract
Analytical Approaches to Improving Power Efficiency in Reversed Doherty Power Amplifiers.
Abstract
This study investigates the performance in output power and efficiency enhancements of Reversed Doherty Power Amplifiers (RDPA) compared to Conventional Doherty Power Amplifiers (CDPA) under varying Quarter-Wave Transformer Losses (QWTL) from 1 dB to 5 dB. The RDPA achieves a comparable maximum output power (Psat) of 47.55 dBm, with a 6 dB back-off point showing consistent performance superiority, maintaining a lead of 0.7–2.9 dB across QWTL conditions. Despite a 1.25 dB decrease in saturation power due to QWTL, RDPA demonstrates a notable improvement in Power Added Efficiency (PAE), achieving 43% at 6 dB back-off, compared to CDPA’s 35%. Efficiency at other load conditions (OBO) for RDPA also consistently outperforms CDPA, with PAE ranging from 3.79% to 25.83% depending on QWTL and Drain efficiencies (DE) of the carrier and peaking amplifiers. These results highlight the RDPA’s resilience to QWT losses and its potential for energy-efficient wireless applications, positioning it as a strong candidate for next-generation high-efficiency amplifier designs.
Keywords: CMOS, Attenuator.
Efficient Neural Implicit representation based Dental 3D reconstruction from single panoramic X-ray radiograph
Abstract