Microwave Characterization of Partially Magnetized Ferrites

In order to assist the microwave engineer in predicting the performance of partially magnetized devices, we have characterized the microwave permeability of partially magnetized materials. The real part of the tensor permeability elements, /spl mu/, /spl kappa/, and /spl mu//sub z/, depends primarily on the parameters /spl gamma/4/spl pi/M//spl omega/ and /spl gamma/4/spl pi/M/sub s/ / /spl omega/. Empirical formulas have been developed which show the dependence. At frequencies sufficiently below /spl omega/ = /spl pi/4/spl pi/M/sub s/, the loss can be characterized by the value of /spl mu/' at 4/spl pi/M = 0./spl mu/, /spl kappa/, and /spl mu//sub z/ depend weakly on composition, whereas /spl mu/' (4/spl pi/M = 0) does depend upon the chemical composition.     

Parallel Component µ /sub z/ of Partially Magnetized Microwave Ferrites

A formula for the parallel component µ /sub z/ of the microwave permeability tensor in the partially magnetized state is derived. The theory is in good agreement with the experimental results.     

高功率低损耗852 nm法布里-珀罗激光器的研制

理论分析了内部损耗、内量子效率对激光器输出功率的影响,并采用PICS3D软件对852 nm法布里-珀罗(FP)激光器进行综合优化设计.设计的器件具有小远场发散角、低内部损耗和高内量子效率等特点,并在大电流下能够实现稳定的高功率输出.实验制备了基横模852 nm FP激光器,内部损耗小于1cm-1,快轴发散角为42.3°...     

低损耗高阻带抑制声表面波滤波器

为了提高雷达信号的接收灵敏度,提出一种低损耗高性能的单相单向换能器,其设计采用了电极宽度控制来实现。发射和接收叉指换能器分别选取适当的加权函数,能得到更低的旁瓣电平。设计制作了中心频率67 MHz,3 dB带宽1 MHz,单向性为21 dB,插损3.8 dB,阻带抑制大于45 dB的低损耗高阻带抑制声表面波滤波器。     

一种大功率宽频带低损耗定向耦合器的设计与实现

根据传输线变压器串并联同时耦合的原理,设计了一种13dB铁氧体定向耦合器,该定向耦合器是用漆包线绕在射频铁氧体磁芯上做成.具有尺寸小、结构简单和频带宽等优点,工作范围在100～400MHz.对其参数进行了理论计算和测量,满足设计要求.经过实际应用,验正了设计方法的可行性.     

一款低功耗高精度A/D变换器

介绍一款低功耗，3V工作电压和0.05%精度的A/D变换器。     

High Power Highly Nonlinear Holey Fiber with Low Confinement Loss for Supercontinuum Light Sources

The high power holey fiber is an efficient supercontinuum light source by using picosecond pulse, which is a less expensive laser source compared with low power and expensive femtosecond laser sources. In this paper, a high power highly nonlinear holey fiber (HN-HF) with a low confinement loss is proposed for supercontinuum light sources. The finite difference method is used to calculate the different properties of the proposed HN-HF. High nonlinear coefficients are obtained at 1.06 μm, 1.31 μm, and 1.55 μm wavelengths with flattened chromatic dispersion and low confinement losses simultaneously. Moreover, numerical simulation results show that high power broad supercontinuum spectra with very short length of the proposed photonic crystal fiber are achieved.     

Ka-Band Rectangular-Waveguide Gysel Power Divider with Low Insertion Loss and High Output Isolation

A Ka-band Gysel power divider based on rectangular waveguide is presented in this paper. The model and equivalent circuit of the presented power divider is introduced. The even- and odd-mode analytical method is applied to analyze the equivalent circuit. A Ka-band waveguide Gysel power divider is designed, optimized, fabricated, and measured. Good agreement between the simulated and measured results is demonstrated. The measured average insertion loss is approximately 0.25 dB from 30 to 34 GHz. The measured output isolation in the same frequency band is greater than 15 dB.     

一种新颖的实现大小功率切换的技术

针对大功率雷达发射组件大小功率切换技术的要求,利用环行器3个端口环行的特点,提出了一种新颖且更易于实现的大小功率切换技术。该技术只需一个PIN二极管单刀单掷的大功率射频开关,便可实现大小功率的切换,且射频开关无需通过大功率,只需对其进行反射,因此大幅降低了实现难度。同时,采用该技术研制了一部S波段发射组件,其大功率输出达到1 500 W以上,成功实现了大小功率的切换,且功率容量和切换速度均满足设计要求,具有较高的实用性。     

基于CMOS工艺的一种低功耗高增益低噪声放大器

采用0.18μm CMOS工艺,两级共源结构实现了低功耗高增益的低噪声放大器设计。共源结构的级联采用电流共享技术,从而达到低功耗的目的。电路的输入端采用源极电感负反馈实现50Ω阻抗匹配,同时两级共源电路之间通过串联谐振相级联。该LNA工作在5.2 GHz,1.8 V电源电压,能提供20 dB的增益(S21为20 dB),而噪声系数为1.9 dB,输入匹配较好,S11为-32 dB。     

一种高速高可靠性低功耗的电平位移电路

为了满足MHz以上频率的GaN半桥栅驱动系统的应用需求,提出了一种高速高可靠性低功耗的低FOM电平位移电路。串联可控正反馈电平位移电路通过仅在转换过程中减弱正反馈力度,实现了低传输延迟和高共模噪声抗扰能力,同时采用最小短脉冲电路设计以降低功耗。该电平位移电路基于0.5μm 80 V高压(HV)CMOS工艺进行设计与仿真验证,结果表明,电路具有960 ps的传输延时、50 V/ns的共模噪声抗扰能力和0.024 ns/(μm·V)的FOM值。     

一种低损耗高抑制的声表面波滤波器

该文采用周期调制及双通道设计的方法实现了一种低损耗高抑制声表面波滤波器的研制。该滤波器以64°Y X LiNbO3为基片材料,其中心频率约475 MHz,插入损耗小于2 dB,阻带抑制优于60 dB及1 dB相对带宽约5%。研制的滤波器具有低插损及高阻带抑制的特性,结果表明该设计方法具有很好的实用性。     

High Power Ferromagnetic Resonance at X-Band in Polycrystalline Garnets and Ferrites

Resonance experiments have been performed at X-band on spherical samples of polycrystalline yttrium garnet, yttrium-gadolinium garnet, yttrium-holmium garnet and nickel-cobalt ferrite. The RF field strength extended up to 60 Oersted. In the case of yttrium garnet the samples differed considerably in density and hence in Iinewidth. At fairly low power levels the susceptibility at resonance varies linearly with the square of the RF magnetic field strength. At high power levels the susceptibility is inversely proportional to the amplitude of the microwave magnetic field. The "spin-wave Iinewidth" Delta H/sub k/ is inferred by extrapolation from the behavior at very high powers. It is found that Delta H/sub k/ is, to a large extent, independent of the Iinewidth Delta H/sub k/ observed by the usual low power experiments. In particular Delta H/sub k/ was found to be essentially the same (approximately 4 Oe) for all yttrium iron garnets (single crystals and polycrystals with linewidth varying between 1.8 Oe and 450 Oe). On the other hand, Delta H/sub k/ increases very rapidly if the yttrium is partially substituted by holmium (Delta H/sub k/~11 Oe for 1 per cent substitution.)     

一种低功耗高稳态电平位移电路

提出了一种新型低功耗、高稳态电平位移电路。该电路能将5 V输入电压转换为10 V输出电压,在电路的初态和电平转换过程中均保持高稳态。采用瞬态增强结构,能加速电平信号之间的转换,有效地减小了传输延迟,提高了电路稳定性。瞬态增强结构在稳定状态时不发挥作用,减小了静态功耗,获得了低功耗。基于标准0.35 μm BCD工艺和多5 V LDMOS耐压器件,对该电平位移电路在5 MHz频率下进行验证。结果表明,动态功耗仅为24.8 μA,上升沿响应速度仅为12.7 ns,下降沿响应速度仅为22.8 ns。该电路具有可靠性高、功耗低的优点。     

一种低插损高隔离度毫米波SPDT开关

基于55 nm CMOS工艺,设计了一种工作于28 GHz的对称型单刀双掷(SPDT)开关.采用串并联拓扑结构实现高隔离度,通过MOS管与电感器构成的开关电感进行LC阻抗匹配,从而实现了低插入损耗和较小芯片面积.开关管采用悬浮衬底设计,减小了插入损耗,提高了线性度.仿真结果表明,该SPDT开关在工作频率下,插入损耗小于...     

高速低功耗传输电路的时钟系统设计

利用锁相环(PLL)为高速低功耗并行传输电路发射机生成时钟信号的系统。设计了一个稳压器(Voltage Regulator),为PLL中对噪声敏感的模块提供低噪声的电压源。在此基础上提出了一种新型的动态改变工作频率的方法,应用于源同步(source-synchronous)模式的高速传输电路。此方法可以在不改变PLL状态的情况下快速改变输入输出(I/O)电路的工作频率,降低功耗。整个芯片采用0.18μm CMOS工艺设计并流片测试成功。     

A BIST TPG for Low Power Dissipation and High Fault Coverage

This paper presents a low hardware overhead test pattern generator (TPG) for scan-based built-in self-test (BIST) that can reduce switching activity in circuits under test (CUTs) during BIST and also achieve very high fault coverage with reasonable lengths of test sequences. The proposed BIST TPG decreases transitions that occur at scan inputs during scan shift operations and hence reduces switching activity in the CUT. The proposed BIST is comprised of two TPGs: LT-RTPG and 3-weight WRBIST. Test patterns generated by the LT-RTPG detect easy-to-detect faults and test patterns generated by the 3-weight WRBIST detect faults that remain undetected after LT-RTPG patterns are applied. The proposed BIST TPG does not require modification of mission logics, which can lead to performance degradation. Experimental results for ISCAS'89 benchmark circuits demonstrate that the proposed BIST can significantly reduce switching activity during BIST while achieving 100% fault coverage for all ISCAS'89 benchmark circuits. Larger reduction in switching activity is achieved in large circuits. Experimental results also show that the proposed BIST can be implemented with low area overhead.     

一种用于电子标签的低功耗高精度时钟电路设计

设计了一种适合射频电子标签的高精度时钟产生电路,在分析影响输出频率稳定性各因素的基础上,针对标签电路低功耗宽工作环境的要求,提出一种全CMOS结构带隙基准做偏置的电流受限型环形振荡器.全MOS自偏置PTAT迁移率和阈值电压互补偿带隙基准源的设计,使时钟电路受电源电压和温度的影响极小.全电路采用TSMC 0.18 μm CMOS工艺实现.HSpice仿真结果表明:电源电压为1.2～2 V,温度从-10～ 70 ℃变化时,带隙基准温度系数和电源电压抑制比分别为12 ppm/℃和59 dB,时钟稳定度在±2.5%以内,电路平均功耗仅为4 μw.     

一种低损耗波导高通滤波器的设计方法

针对Ka频段卫星通信系统中对阻收滤波器的工程应用需求,提出一种低损耗波导高通滤波器的设计方法。利用波导低频截止特性及阶梯阻抗变换法,在软件中进行建模仿真优化后,通过参数扫描得到一个合理的设计方案。实物测试结果表明通带25～28 GHz插入损耗＜0.4 dB;阻带22～23 GHz抑制＞40 dB,是一款可应用于实际工程的高性能滤波器。     

用于高速串行收发器的低功耗静噪检测器

提出了一种基于0.13 μm CMOS工艺实现的低功耗静噪检测器,可应用于通用串行总线(USB)等高速串行数据链路。该静噪检测器包括电平转换器、比较器和输出检测器。电平转换器中,引入了基准电流源和电流镜,电源电压较传统电路降低20％以上。仿真结果表明,在1.35~1.65 V电源电压、0℃~70℃温度范围内,在480 Mbit/s输入数据速率下,静噪检测阈值电压的最大值、最小值分别为140 mV、106 mV。电路面积为0.036 mm²,功耗仅为3.7 mW@1.5 V。