Continuous Time Universal Filters using Unity Gain Cells

A new circuit configuration for continuous time universal filters using current and voltage followers is proposed. The new configuration employs small number of passive elements. It provides independent control over all filterdesign aspects mainly the natural frequency, ω_o, quality factor, Q, and gain. It also allows complete MOS non-linearity cancellation, thus is suitable MOS-C continuous-time fully integrated filters. Analysis ofthe non-idealities associated with the active elements is included. HSpice simulations that confirm theoretical analysis are included.     

A Microwave Hybrid with Impedance Transforming Properties (Correspondence)

A 3-port hybrid useful for combining equiphase equiamplitude signals or for dividing an input into two such signals is described. Design equations are presented for matching arbitrary complex loads at the equiphase-equiamplitude ports to a real load at the third port.     

A Review on Scaling Up Perovskite Solar Cells

Power conversion efficiency of perovskite solar cells (PSCs) has been boosted to 25.5% among the highest efficiency for single-junction solar cells, making PSCs extremely promising to realize industrial production and commercialization. Scaling up PSCs to fabricate efficient perovskite solar modules (PSMs) is the fundamental for applications. Here, present progresses on scaling up PSCs are reviewed. The structure design for PSMs is discussed. Various scalable methods and related morphology control strategies for large-area uniform perovskite films are summarized. Potential charge transport materials and electrode materials together with their scalable methods for low-cost, efficient, and stable PSMs are also summarized. Besides, current attempts on encapsulation for improving stability and reducing lead leakage are introduced, and the calculated cost and environment influence of PSMs are also outlined.     

宽阻带阶跃阻抗发夹线带通滤波器设计

提出了新的抑制微带带通滤波器寄生通带的方法。这种方法通过级联阶跃阻抗发夹线谐振器构成的椭圆函数低通滤波器于带通滤波器的输入/输出端,显著改善了后者的阻带抑制特性。本文基于新的等效电路模型,推导出了此类低通滤波器的阻带传输零点位置。设计了L波段宽阻带阶跃阻抗发夹线带通滤波器验证了理论分析和设计过程的正确性。     

通道增益的有源估计方法

在DOA估计中解决通道不一致性问题的关键是设法求得各通道的复增益。本文利用在天线阵列所在平面设置的一个校正源，运用信号空间对信号DOA和通道增益的约束关系对通道增益进行估计，在未知校正信号DOA时可通过迭代的方法获得二者的一致估计。仿真证明了此方法的有效性。     

一种指数增益控制宽范围可变增益放大器

采用中芯国际(SMIC)0.18μm CMOS工艺设计了一种具有指数增益特性的的宽增益调节范围的可变增益放大器,该放大器由Gilbert单元、指数电压转换电路、直流消除电路及超级源级跟随器组成。经过Cadence仿真验证,该放大器可以实现-11.14dB~30.39dB的增益连续变化,其-3dB带宽为250MHz,控制电压与增益成dB线性关系。     

Sallen and Key Filter Networks with Amplifier Gain Larger than or Equal to Unity

Noninverting operational amplifiers cannot readily be used for various Sallen and Key filters because they cannot provide gain less than unity. A simple network modification is suggested that overcomes this limitation and introduces an added degree of freedom with parameters that are determined by passive components only.     

A Unity Gain High Speed Buffer to Improve Signal Integrity in High Frequency Test Interface

The availability of faster electronic components allows the design of more effective and efficient test equipments. However in high-speed applications, the effect of interconnects between the tester and the device under test DUT introduces ringing, overshoot and timing delay problems. In this paper we present an output high speed buffer which helps to cancel the overshoot, undershoot, and ringing. The buffer which has a unity gain, presents a high output current and introduces small delay. It is able to drive the comparator of the tester through the transmission line with minimum distortion of the signal. Compared with other approaches, the use of this output buffer provides good improvement of the signal. This output buffer which is designed for the interface between tester and DUT can be considered for communication between high speed devices in printed circuits boards. The calibration procedure is explained in order to determine the delay introduced by the buffer and to measure low and high voltage levels of the digital output signal of the buffer.     

基于ChirpScaling算法的星载SAR成像处理实现方法

本文提出一种基于ＣｈｉｒｐＳｃａｌｉｎｇ（ＣＳ）算法的星载合成孔径雷达成像处理实现方法，该算法与目前国际上通用的距离－多普勒算法相比，由于避免了插值运算，且能够精确地进行距离徒动校正，使得成像质量优于精的ＲＤ算法。     

一种高增益分形微带阵列天线

采用2阶皮亚诺分形曲线,设计了一种具有高增益端射特性的微带阵列天线。该阵列天线由多段皮亚诺分形曲线组成,通过添加微带相移器,分形曲线构成了一个偶极子天线阵列。文中介绍和分析了该分形阵列天线的工作原理、结构和主要参数对性能的影响。设计并制作了一只工作于5.8 GHz的分形阵列天线,仿真和测试结果表明,该天线具有良好的辐射特性,其端射增益达19 dB,旁瓣＜-12 dB,交叉极化＞30 dB,天线口径效率超过90%。     

一种具有精确增益控制的CMOS可编程增益放大器

采用0.13μm RF CMOS工艺,设计了一款具有精确增益步长控制的宽带可编程增益放大器.在传统电阻网络衰减器的基础上,提出了一种新的增益控制方法.该方法采用两个互相重叠的反馈环路,通过改变环路中跨导的比值以实现精细的增益步长控制.测试结果表明,当电源电压为1.2V时,功耗为24 mW,-3 dB带宽为600MHz....     

A Compact Dual-Band Bandpass Filter Using Meandering Stepped Impedance Resonators

This letter presents a miniaturized dual-band narrow bandpass filter (BPF) using meandering stepped impedance resonators (SIRs) with a new coupling scheme, which exhibited a size reduction of 50% compared with the traditional direct coupling structure at the same frequency, while the new structure can generate three transmission zeros in the insertion loss response. To validate the design and analysis, two dual-band BPFs centered at 2.4-GHz/5.2-GHz and 2.4-GHz/5.7-GHz for WLAN application were fabricated and measured. It is shown that the measured and simulated performances are in good agreement. The BPFs achieved insertion loss of less than 2 dB and return loss of greater than 16-dB in each band.     

Shedding Light on the Operation of Polymer Light‐Emitting Electrochemical Cells Using Impedance Spectroscopy

A combination of impedance spectroscopy, device characterization, and modeling is used to pinpoint key processes in the operation of polymer light‐emitting electrochemical cells (LECs). At low applied voltage, electric double layers with a thickness of ≈2–3 nm are shown to exist at the electrode interfaces. At voltages exceeding the bandgap potential of the conjugated polymer (V ≥ 2.5 V for superyellow), a light‐emitting p–n junction forms in situ, with a steady‐state structure that is found to depend strongly on the applied voltage. This is exemplified by that the effective p–n junction thickness (d_pn) for a device with an interelectrode gap of 90 nm decreases from ≈23 nm at 2.5 V to ≈6 nm at 3.9 V. The current increases with decreasing d_pn in a concerted manner, while the brightness reaches its peak at V = 3.4 V when d_pn ≈ 10 nm. The existence of an optimum d_pn for high brightness in LECs is attributed to an offset between an increase in the exciton formation rate with decreasing d_pn, due to an increasing current, and a simultaneous decrease in the exciton radiative decay rate, when an increasing fraction of excitons diffuses away from the p–n junction into the surrounding non‐radiative doping regions.     

A NEW APPROACH OF LADDER SIMULATION ACTIVE BANDPASS FILTER——USING COMPLEX SCALING AND NIC EMBEDDING

Here we present a new method of constructing ladder simulation filters using the complex scaling and negative immittance converter (NIC) embedding. This method saves the number of operational amplifiers, and thereby lowers the cost and power consumption. It also avoids floating elements, and is easy to adjust. It still acquires the merit of low sensitivity. The problem of error minimization and stability are also discussed.     

一种具有新型增益控制技术的CMOS宽带可变增益LNA

高速超宽带无线通信的多标准融合是未来射频器件的发展趋势,该文提出一种基于CMOS工艺、具有新型增益控制技术的宽带低噪声放大器(LNA),采用并联电阻反馈实现宽带输入匹配,并引入噪声消除技术来减小噪声以提高低噪声性能;输出带有新型6位数字可编程增益控制电路以实现可变增益。采用中芯国际0.13m RF CMOS工艺流片,芯片面积为0.76 mm2。测试结果表明LNA工作频段为1.1-1.8 GHz,最大增益为21.8 dB、最小增益8.2 dB,共7种增益模式。最小噪声系数为2.7 dB,典型的IIP3为-7 dBm。     

一种利用二管EEPROM单元实现四值存储的方法

提出了一种利用常见的二管ＥＥＰＲＯＭ实现四值存储的方法,相对于用四管单元实现四值存储,该方法节省了芯片面积,使ＥＥＰＲＯＭ芯片的存储量增加一倍,由于只是在读写控制电路上加以改进,故适用于几乎所有通常的二管结构的ＥＥＲＰＯＭ单元,且对单元性能影响较小。     

一种高分辨力的可编程阻抗

论述了采用两片乘法数模变换器把输入的数字码变换电阻和电抗的简单而有效的电路，该电路实现的功能等效为对端口处等效电阻抗的数字编程，具有分辨力高的特点，此电路可用于动态皮肤阻抗模拟器、可编程滤波器、信号发生器、数字测量电桥、阻抗标准。     

一种利用衰减器实现的超宽带可变增益放大器

提出了一种基于有源可调衰减器的超宽带可变增益放大器,以有源可调衰减器作为可变增益放大器的核心,并与高增益放大器级联,在3.1～10.6 GHz超宽频带内实现了宽动态增益调节范围.基于Jazz 0.35 μm SiGe HBT工艺,完成了超宽带可变增益放大器的设计,利用安捷伦公司的ADS仿真软件进行仿真验证.结果表明,在3.1～10.6 GHz的超宽频带内,当电压在0.7～2.0V的范围内变化时,该放大器的动态增益变化范围大于60 dB,3dB带宽大于7 GHz,在整个电压变化范围内,S11和S22均低于-10 dB,在最大增益处,噪声系数小于5dB.     

一种指数增益控制型高线性CMOS中频可变增益放大器

采用跨导线性化技术设计了一种具有指数增益特性的高线性中频可变增益放大器.该放大器由电流调节型可变增益单元、宽范围指数电压转换电路及固定增益放大器构成.基于0.25μm CMOS工艺的测试结果表明,放大器实现了8～48dB的增益连续变化,差分输出1V峰峰值下的三阶互调失真小于-60dBc,最大增益处噪声系数为8.7dB,50Ω负载下三阶输出截点为14.2dBm.     

A Differential CMOS Current-Mode Variable Gain Amplifier with Digital dB-Linear Gain Control

A novel CMOS variable gain amplifier operating on current signals with a dB-linear gain control is presented. The gain control is achieved by multiplying a digitally synthesized exponentially varying control current signal by a differential input signal in the current domain. A current amplifier at the output sets the gain to the desired level. Current-mode operation allows for a reduced supply voltage by minimizing the voltage swing at the low impedance nodes of the circuit. Multiple circuit realizations for various blocks are presented allowing for designs meeting different constraints. Experimental realization of the variable gain amplifier shows the validity of the presented approach.