Detailed investigation of active CMOS mixers noise in submicron technology

A unified noise figure expression incorporating the thermal noise and flicker noise has been proposed for active CMOS mixers. Based on the derived conversion functions with output resistance effect, the noise transforming factors for different stages are numerically computed to rigorously describe the noise output. The subthreshold conductance has also been taken into account by utilizing the latest continuous noise model and the simplified MOSFET I-V model. As a result, the frequency-dependent characteristic of noise expression is of competency for explaining the flicker noise mechanism, thus can be directly applied to active CMOS mixers with any IF characteristics. And good agreement is obtained between simulations and measurements.     

C波段pHEMT单片Gilbert混频器

采用0.5μmpHEMT工艺研制了Gilbert式单片混频器,设计采用了电流注入技术及跨导级源端负反馈技术,在C波段测试表明:变频增益大于1.5dB,单边带噪声系数典型值为12.5dB,变频带宽约为DC～1GHz,所需本振功率实测值为1.6dBm。     

A Different Laboratory Tale: Fifty Years of Mössbauer Spectroscopy

I explore the fifty-year development of M?ssbauer spectroscopy by focusing on three episodes in its development at Argonne National Laboratory: work by nuclear physicists using radioactive sources in the early 1960s, work by solid-state physicists using radioactive resources from the mid- 1960s through the 1970s,and work by solid-state physicists using the Advanced Photon Source from the 1980s to 2005. These episodes show how knowledge about the properties of matter was produced in a national-laboratory context and highlights the web of connections that allow nationallaboratory scientists working at a variety of scales to produce both technological and scientific innovations.     

用于2.4GHz无线局域网收发机的CMOS混频器

描述了采用CMOS工艺技术,用于2 .4GHz无线局域网收发机的上变频器/下变频器的实现.由于采用class-AB类工作模式的输入级,该下变频器具有很高的线性度.同时,该输入级也完成了输入阻抗匹配和单端信号到差分信号的转换功能.它们采用0 .18μm CMOS工艺实现.为了说明它们的性能,文中给出了每个模块的测试结果.     

An Efficient Geometric Integrator for Thermostatted Anti-/Ferromagnetic Models

(Anti)-/ferromagnetic Heisenberg spin models arise from discretization of Landau–Lifshitz models in micromagnetic modelling. In many applications it is essential to study the behavior of the system at a fixed temperature. A formulation for thermostatted spin dynamics was given by Bulgac and Kusnetsov, which incorporates a complicated nonlinear dissipation/driving term while preserving spin length. It is essential to properly model this term in simulation, and simplified schemes give poor numerical performance, e.g., requiring an excessively small timestep for stable integration. In this paper we present an efficient, structure-preserving method for thermostatted spin dynamics.     

Dynamic susceptibility of thin films with perpendicular magnetic anisotropy

We investigate the spin dynamics related to the Gilbert damping constant in infinite continuous thin films with perpendicular magnetic anisotropy (PMA), based on numerical and analytic approaches. We obtain the dynamic susceptibility of the infinite continuous thin films with various PMA energies by using micromagnetic simulations with periodic boundary conditions. These results are compared with the analytic solution that we derived from the Landau–Lifshitz–Gilbert equation. Based on our numerical and analytic studies, we support the physical analysis for results in the experimental determination of the Gilbert damping constant for PMA materials.     

BiCMOS工艺的高线性度下变频混频器设计

利用BiCMOS工艺设计了一种高线性度下变频混频器.在此变频混频器的设计中结合了双极型工艺在射频段的高性能以及MOS工艺的高线性度,并利用其对传统的吉尔伯特单元进行了优化.基于JAZZ 0.35μm标准BiCMOS SBC35工艺设计参数对混频器进行了设计和仿真,仿真结果表明该混频器获得了良好的性能指标,转换增益为9.3 dB,输入3阶互调点达到了16 dBm,在5 V单电源下消耗1.9 mA的电流.     

基于0.18μm SiGe BiCMOS工艺的25Gb/s宽带可变增益放大器

介绍了一种基于0.18 μm SiGe BiCMOS工艺的,可应用于高速通信的25 Gb/s可变增益放大器(VGA).该放大器由核心电路、输出缓冲器和偏置电路组成,核心电路采用改进型Gilbert结构,增大了电路的增益动态范围;同时采用电感峰化技术克服大寄生电容来实现宽带特性.后仿真结果表明,该可变增益放大器的最大增益为20.15 dB,-3 dB带宽(BW)为26.8 GHz,可支持高达25 Gb/s的数据速率,在3.3 V电源电压下的功耗为26.4 mW,芯片大小为1 120 μm×1 167 μm.