Research and Design of X-band Low Noise Amplifier Based on CMOS Process

Based on CMOS process, a low noise amplifier(LNA) operating at 7.4GHz~11.4GHz was designed. The two-stage differential cascode structure is adopted. Transformer was used to achieve inter-stage matching. Balun was used to achieve input and output matching, which reduces the number of inductors used, effectively reduces the chip size while ensuring good gain and noise figure. The actual measurement results show that the power gain at the center frequency of 9.4GHz is 27dB, the maximum noise figure is less than 3.82dB, the output power 1dB compression point is greater than 8dBm, the chip area is only 0.41mm×0.83mm(excluding PAD).

Analysis and design of diode physical limit bandwidth efficient rectification circuit for maximum flat efficiency, wide impedance, and efficiency bandwidths

Generally, a conventional voltage doubler circuit possesses a large variation of its input impedance over the bandwidth, which results in limited bandwidth and low RF-dc conversion efficiency. A basic aspect for designing wideband voltage doubler rectifiers is the use of complex matching circuits to achieve decade and octave impedance and RF-dc conversion efficiency bandwidths. Still, the reported techniques till now have been accompanied by a large fluctuation of the RF-dc conversion efficiency over the operating bandwidth. In this paper, we propose a novel rectification circuit with minimal inter-stage matching that consists of a single short-circuit stub and a virtual battery, which contributes negligible losses and overcomes these existing problems. Consequently, the proposed rectifier circuit achieves a diode physical-limit-bandwidth efficient rectification. In other words, the rectification bandwidth, as well as the peak efficiency, are controlled by the length of the stub and the physical limitation of the diodes.

Analisis SWOT pada Kantor Jasa Akuntan Yohanes

This research was conducted to find what marketing strategies are appropriate for the Yohanes Accounting Services Office in 2020. This research used data collection techniques by using interviews and observations. The data analysis technique uses the concept of Fred R. David's theory through 3 stages of strategic formulation, namely the input stage, matching stage, and decision stage. The input stage uses the Internal Factor Evaluation (IFE) Matrix and the External Factor Evaluation (EFE) Matrix. The next stage used the SWOT Matrix and Internal-External (IE) Matrix. In the final stage using the Quantitative Strategic Planning Matrix (QSPM). The results showed that the total value for IFE is 2.7081 while the total value for EFE is 3.0850. In the Internal-External (IE) matrix, it is known that Yohanes's Accounting Services Office is in a position of growth and development. Strategies that are suitable for this position are market penetration strategy, market development strategy, and product development strategy. At the decision stage, from the QSPM results, the main strategy alternative to be applied is the market development strategy with a total value of attractiveness (TAS) of 6.7568. This strategy seeks to increase the market share of a product through efforts to make improvements, enhancements, and developments. Penelitian ini dilakukan dengan tujuan untuk mengetahui strategi pemasaran apa yang sesuai diterapkan bagi Kantor Jasa Akuntan Yohanes pada tahun 2020. Pada tahap akhir menggunakan Quantitative Strategic Planning Matrix (QSPM). Berdasarkan hasil dari matriks IFE dan EFE yang dikumpulkan, dapat diketahui total nilai untuk IFE adalah sebesar 2,7081 sedangkan total nilai untuk EFE adalah sebesar 3,0850. Pada matching stage pada matrik SWOT didapatkan beberapa kemungkinan alternatif strategi dengan cara menggunakan kekuatan yang dimiliki untuk memanfaatkan peluang, memanfaatkan peluang untuk mengatasi kelemahan, menggunakan kekuatan yang dimiliki untuk menghindari ancaman dan meminimalisasikan kelemahan dan menghindari ancaman. Pada matrik Internal-Eksternal (IE) diketahui bahwa Kantor Jasa Akuntan Yohanes berada pada posisi tumbuh dan bina, strategi yang cocok pada posisi ini adalah strategi penetrasi penetrasi pasar, startegi pengembangan pasar dan strategi pengembangan produk. Pada decision stage dari hasil QSPM dapat diperoleh alternatif strategi utama yang diterapkan yaitu strategi pengembangan pasar dengan Total Nilai Daya Tarik (TAS) sebesar 6,7568. Strategi ini berusaha untuk meningkatkan pangsa pasar suatu produk melalui usaha melakukan perbaikan, peningkatan dan pengembangan.

Hub clearance effect in the design space of the cantilevered stator embedded in a 4-stage low-speed research compressor

This paper focuses on the effect of hub clearance in the design space of the highly loaded cantilevered stator. The embedded 1.5 stages of a low-speed research compressor (LSRC) were conducted with Unsteady Reynolds Average Navier-Stokes (URANS) numerical investigation, and the cantilevered stator adopts positive bowed and fore-sweep three-dimensional design. The research details that with the hub clearance increasing from 1.1% to 4.5% span, the loss coefficient and the total leakage momentum of the cantilevered stator correspond to the change of the blade loading near the hub. When designing the inlet metal angle of the rotor downstream the cantilevered stator, emphasis should be given to considering the inter-stage matching below 15% span. The mixing of leakage flow in 1.1% span clearance and 2.5% span clearance is basically completed in the S3 passage, but the mixing of leakage flow in 3.5% span clearance and 4.5% span clearance is still relatively strong downstream of S3. When calculating the relative entropy variation based on Denton’s mixing model, attention should be paid to the relationship between the leakage flow velocity affected by the hub gap and the mainstream velocity, as well as whether the mixing has been completed in the blade passage.

Space-Compliant Design of a Millimeter-Wave GaN-on-Si Stacked Power Amplifier Cell through Electro-Magnetic and Thermal Simulations

The stacked power amplifier is a widely adopted solution in CMOS technology to overcome breakdown limits. Its application to compound semiconductor technology is instead rather limited especially at very high frequency, where device parasitic reactances make the design extremely challenging, and in gallium nitride technology, which already offers high breakdown voltages. Indeed, the stacked topology can also be advantageous in such scenarios as it can enhance gain and chip compactness. Moreover, the higher supply voltages and lower supply currents beneficially impact on reliability, thus making the stacked configuration an attractive solution for space applications. This paper details the design of two stacked cells, differing in their inter-stage matching strategy, conceived for space applications at Ka-band in 100 nm GaN-on-Si technology. In particular, the design challenges related to the thermal constraints posed by space reliability and to the electro-magnetic cross-talk issues that may arise at millimeter-wave frequencies are discussed. The best cell achieves at saturation, in simulation, 3 W of output power at 36 GHz with associated gain and efficiency in excess of 7 dB and 35%, respectively.

Diode physical-limit-bandwidth efficient rectification

Generally, a conventional voltage doubler circuit possesses a large variation of its input impedance over the bandwidth, which results in limited bandwidth and low RF-dc conversion efficiency. A basic aspect for designing wideband voltage doubler rectifiers is the use of complex matching circuits to achieve decade and octave impedance and RF-dc conversion efficiency bandwidths. Still, the reported techniques till now have been accompanied by a large fluctuation of the RF-dc conversion efficiency over the operating bandwidth. In this paper, we propose a novel rectification circuit with minimal inter-stage matching that consists of a single short-circuit stub and a virtual battery, which contributes negligible losses and overcomes these existing problems. Consequently, the proposed rectifier circuit achieves a diode physical-limit-bandwidth efficient rectification. In other words, the rectification bandwidth, as well as the peak efficiency, are controlled by the length of the stub and the physical limitation of the diodes.

Integrated Optimization Strategy for Sustainable Shared Designated Driver Ferry Vehicle Scheduling

The focus of this study is on optimizing the schedule adjustment scheme of shared designated driver ferry vehicles to obtain a sustainable and energy-efficient system to pick up and drop off designated drivers to serve drunk customers. A two-stage matching model for driver and customer supply and demand matching and driver ferry vehicle dispatching is designed in order to optimize the total distance travelled and minimize the generalized deviation costs. A maximum residual time adjustment algorithm is designed to reduce the logarithm of new interference demand, and a tabu search algorithm is used to solve the schedule adjustment scheme for ferry vehicles. The validity of the model and the algorithm is verified by a multiperiod example constructed in the Solomon test question bank. The result of numerical experiments shows that the proposed model and algorithm can solve the disruption adjustment scheduling strategy of shared designated driver ferry vehicles. The integrated optimization strategy can effectively improve the utilization rate and the operation efficiency of the shared driver ferry vehicles to reduce operation cost and energy consumption.

An Efficient Method to Quantify Structural Distributions in Heterogeneous cryo-EM Datasets

Cryogenic Electron Microscopy (cryo-EM) preserves the ensemble of protein conformations in solution and thus provide a promising way to characterize conformational changes underlying protein functions. However, it remains challenging for existing software to elucidate distributions of multiple conformations from a heterogeneous cryo-EM dataset. We developed a new algorithm: Linear Combinations of Template Conformations (LCTC) to obtain distributions of multiple conformations from cryo-EM datasets. LCTC assigns 2D images to the template 3D structures obtained by Multi-body Refinement of RELION via a novel two-stage matching algorithm. Specifically, an initial rapid assignment of experimental 2D images to template 2D images was applied based on auto-correlation functions of image contours that can efficiently remove the majority of irrelevant 2D images. This is followed by pixel-pixel matching of images with fewer number of 2D images, which can accurately assign the 2D images to the template images. We validate the LCTC method by demonstrating that it can accurately reproduce the distributions of 3 Thermus aquaticus (Taq) RNA polymerase (RNAP) structures with different degrees of clamp opening from a simulated cryo-EM dataset, in which the correct distributions are known. For this dataset, we also show that LCTC greatly outperforms clustering-based Manifold Embedding and Maximum Likelihood-based Multi-body Refinement algorithms in terms of reproducing the structural distributions. Lastly, we also successfully applied LCTC to reveal the populations of various clamp-opening conformations from an experimental Escherichia coli RNAP cryo-EM dataset. Source code is available at https://github.com/ghl1995/LCTC.

Diode physical-limit-bandwidth efficient rectification

Generally, a conventional voltage doubler circuit possesses a large variation of its input impedance over the bandwidth, which results in limited bandwidth and low RF-dc conversion efficiency. A basic aspect for designing wideband voltage doubler rectifiers is the use of complex matching circuits to achieve decade and octave impedance and RF-dc conversion efficiency bandwidths. Still, the reported techniques till now have been accompanied by a large fluctuation of the RF-dc conversion efficiency over the operating bandwidth. In this paper, we propose a novel rectification circuit with minimal inter-stage matching that consists of a single short-circuit stub and a virtual battery, which contributes negligible losses and overcomes these existing problems. Consequently, the proposed rectifier circuit achieves a diode physical-limit-bandwidth efficient rectification. In other words, the rectification bandwidth, as well as the peak efficiency, are controlled by the length of the stub and the physical limitation of the diodes.