A Cryogenic Broadband Sub-1-dB NF CMOS Low Noise Amplifier for Quantum Applications

A cryogenic broadband low noise amplifier (LNA) for quantum applications based on a standard 40-nm CMOS technology is reported. The LNA specifications are derived from the readout of semiconductor quantum bits at 4.2 K, whose quantum information signals are characterized as phase-modulated signals. To achieve broadband input matching impedance and low noise figure, the gate-to-drain capacitance of the input transistor is exploited. The goal is to involve a resistive and capacitive load into the input impedance match of a common-source stage with source inductive degeneration. The capacitive load is created by an LC parallel tank whose resonant frequency is lower than the operating frequency. The achieved non-constant in-band equivalent capacitance is proven to be beneficial to input impedance matching. The resistive part of the load is provided by the transconductance of the cascode stage implicitly. An inductor is added to the gate of the cascode transistor to suppress its noise, and a transformer-based resonator with two resonant frequencies serves as the load of the first stage, thus extending the operating bandwidth. Design considerations for the cryogenic temperature operation of the LNA are proposed and analyzed. The LNA achieves a measured gain (S₂₁) of 35 ± 0.5 dB, return loss > 12 dB, and NF of 0.75-1.3 dB across the band (4.1-7.9 GHz), with 51.1-mW power consumption at room temperature, while it shows a measured gain of 42 ± 3.3 dB, and NF of 0.23-0.65 dB with 39-mW power consumption at 4.2 K between 4.6 and 8 GHz. To the best of our knowledge, this is the first report of a cryogenic LNA based on a bulk CMOS process working above 4 GHz showing sub-1-dB NF both at room and cryogenic temperatures

Interfacing Qubits via Cryo-CMOS Front Ends

This work describes a basic interface between solid-state quantum bits (qubits) and classical environments. We describe a multiplexer, a circulator, and a low noise amplifier, designed for cryogenic temperature operation in a 40 nm CMOS technology node. The circuits take advantage of traditional design styles, such as transmission gates, passive LC filters and switches, and recent developments, such as differential noise cancelling with six-port transformers, while exploiting new cryogenic CMOS (cryo-CMOS) modeling for design and verification purposes

A 7–13 GHz 10 W High-Efficiency MMIC Power Amplifier in 0.25 µm GaN HEMT Process

With the increase in applications of the millimeter wave spectrum for phased array radar systems, mobile 7–13 communication systems, and satellite systems, the demand for a wideband, high-efficiency, high-power monolithic microwave integrated circuit (MMIC) power amplifier (PA) is increasing. In this paper, a 7–13 GHz 10 W high-efficiency MMIC PA is designed. This amplifier consists of a two-stage circuit structure with two high electron mobility transistor (HEMT) cells for the driver stage and four HEMT cells for the power stage. To ensure high efficiency and a certain output power (Pout), both the driver–stage and power–stage transistors use a deep Class–AB bias. At the same time, in order to further improve the efficiency, low-loss and second–harmonic tuning techniques are used in the output and inter-stage matching networks, respectively. Finally, the electromagnetic simulation results show that within a frequency of 7–13 GHz, the amplifier achieves an average saturated continuous wave (CW) Pout of 40 dBm, a small signal gain of 14.5–15.5 dB, a power-added efficiency (PAE) of 30–46%, and the input and output return loss are better than 5 dB and 8 dB, respectively

A 7–13 GHz 10 W High-Efficiency MMIC Power Amplifier in 0.25 µm GaN HEMT Process

With the increase in applications of the millimeter wave spectrum for phased array radar systems, mobile 7–13 communication systems, and satellite systems, the demand for a wideband, high-efficiency, high-power monolithic microwave integrated circuit (MMIC) power amplifier (PA) is increasing. In this paper, a 7–13 GHz 10 W high-efficiency MMIC PA is designed. This amplifier consists of a two-stage circuit structure with two high electron mobility transistor (HEMT) cells for the driver stage and four HEMT cells for the power stage. To ensure high efficiency and a certain output power (Pout), both the driver–stage and power–stage transistors use a deep Class–AB bias. At the same time, in order to further improve the efficiency, low-loss and second–harmonic tuning techniques are used in the output and inter-stage matching networks, respectively. Finally, the electromagnetic simulation results show that within a frequency of 7–13 GHz, the amplifier achieves an average saturated continuous wave (CW) Pout of 40 dBm, a small signal gain of 14.5–15.5 dB, a power-added efficiency (PAE) of 30–46%, and the input and output return loss are better than 5 dB and 8 dB, respectively

Research on Distribution Model and Detection Spacing of Compaction Degree of Asphalt Pavement Based on the PQI Method

The pavement quality indicator (PQI) is a non-destructive piece of equipment for detecting the compaction degree of asphalt pavement, which can avoid primary damage to the pavement compared with the traditional core-drilling method. In this paper, the PQI method was applied to evaluate the compaction quality of asphalt pavement through data collection, calibration and statistical analysis, and the probability-distribution characteristics of compaction degree were also explored, by fitting the data with probability-distribution models. Furthermore, the optimal detection-spacing was determined by comparing the statistical results of compaction degree measured at different detection-spacings. Test results showed that the calibrated PQI data was close to the actual data of the core sample, and their error rate was within 1%. The compaction degree of the test road was mostly located between 92% and 99%, and the variable coefficient was entirely below 2%, demonstrating that the pavement-compaction quality was satisfactory and uniform. The normal distribution model, lognormal distribution model and extreme-value distribution model had relatively high accuracy in fitting the compaction-degree frequency data, while the sine-wave distribution model was low in fitting accuracy. By comparing the predicted value with the actual value of compaction degree, the normal distribution model was determined as the most appropriate model for describing the frequency distribution of compaction degree. In addition, the detection spacing was selected as 50 m, considering the reliability, accuracy and efficiency. The research results provide technical support for the compaction quality-control of asphalt pavement in a non-destructive, timely, accurate and multi-point manner, ultimately contributing to the excellent service performance and service life of asphalt pavement

EZH2 suppression in glioblastoma shifts microglia toward M1 phenotype in tumor microenvironment

Abstract Background Glioblastoma multiforme (GBM) induces tumor immunosuppression through interacting with tumor-infiltrating microglia or macrophages (TAMs) with an unclear pathogenesis. Enhancer of zeste homolog 2 (EZH2) is abundant in GBM samples and cell lines and is involved in GBM proliferation, cell cycle, and invasion, whereas its association with innate immune response is not yet reported. Herein, the aim of this study was to investigate the role of EZH2 in GBM immune. Methods Co-culturing models of human/murine GBM cells with PBMC-derived macrophages/primary microglia were employed. EZH2 mRNAs and function were suppressed by siEZH2 and DZNep. Real-time PCR and flow cytometry were used to determine levels of microglia/macrophages markers. The fluorescence-labeled latex beads and flow cytometry were utilized to evaluate phagocytic abilities of microglia. CCK8 assay was performed to assess microglia proliferation. Results EZH2 inhibition led to significant reduction of TGFβ1-3 and IL10 and elevation of IL1β and IL6 in human and murine GBM cells. More importantly, EZH2 suppression in GBM cells resulted in significant increase of M1 markers (TNFα and iNOS) and decrease of a pool of M2 markers in murine microglia. The proportion of CD206+ cells was decreased in PBMC-derived macrophages as co-incubated with EZH2-inhibited GBM cells. Functional researches showed that phagocytic capacities of microglia were significantly ameliorated after EZH2 inhibition in co-culturing GBM cells and microglia proliferation was declined after addition of TGFβ2 antibodies to co-incubated GBM cells with EZH2 inhibition. Besides, we found that EZH2 suppression in GBM cells enhanced co-culturing microglia engulfment through activation of iNOS. Conclusions Our data demonstrates that EZH2 participates in GBM-induced immune deficient and EZH2 suppression in GBM can remodel microglia immune functions, which is beneficial for understanding GBM pathogenesis and suggests potential targets for therapeutic approaches

A Novel Method to Synthesize Co/Fe3O4 Nanocomposites with Optimal Magnetic and Microwave Performance

The magnetic interactions between neighboring magnetic nanoparticles make the synthesis of nanocomposites made of two kinds of magnetic nanoparticles extremely difficult. In this paper, to achieve an effective nanocomposite of Co and Fe3O4 nanoparticles, a special urchin-like Co nanomatrix was used to prepare the Co/Fe3O4 nanocomposites. The Fe3O4 nanoparticles are evenly embedded into the branches of the CO clusters, bringing the two types of particles into close contact and ensuring the optimal magnetic and microwave properties. The electromagnetic (EM) parameters at 1–18 GHz and the magnetic loss tangents can be effectively modulated, and the absorption frequency bands of the EM waves are shifted to the X-Ku bands (8–18 GHz) from the S-C bands (2–8 GHz) after the Fe3O4 nanoparticles are compounded